1 <chapter id="tools"><title>Supporting Tools</title>
4 In support of the service API - primarily the ASN module, which
5 provides the pro-grammatic interface to the Z39.50 APDUs, &yaz; contains
6 a collection of tools that support the development of applications.
9 <sect1 id="tools.query"><title>Query Syntax Parsers</title>
12 Since the type-1 (RPN) query structure has no direct, useful string
13 representation, every origin application needs to provide some form of
14 mapping from a local query notation or representation to a
15 <token>Z_RPNQuery</token> structure. Some programmers will prefer to
16 construct the query manually, perhaps using
17 <function>odr_malloc()</function> to simplify memory management.
18 The &yaz; distribution includes three separate, query-generating tools
19 that may be of use to you.
22 <sect2 id="PQF"><title>Prefix Query Format</title>
25 Since RPN or reverse polish notation is really just a fancy way of
26 describing a suffix notation format (operator follows operands), it
27 would seem that the confusion is total when we now introduce a prefix
28 notation for RPN. The reason is one of simple laziness - it's somewhat
29 simpler to interpret a prefix format, and this utility was designed
30 for maximum simplicity, to provide a baseline representation for use
31 in simple test applications and scripting environments (like Tcl). The
32 demonstration client included with YAZ uses the PQF.
37 The PQF have been adopted by other parties developing Z39.50
38 software. It is often referred to as Prefix Query Notation
43 The PQF is defined by the pquery module in the YAZ library.
44 There are two sets of function that have similar behavior. First
45 set operates on a PQF parser handle, second set doesn't. First set
46 set of functions are more flexible than the second set. Second set
47 is obsolete and is only provided to ensure backwards compatibility.
50 First set of functions all operate on a PQF parser handle:
53 #include <yaz/pquery.h>
55 YAZ_PQF_Parser yaz_pqf_create (void);
57 void yaz_pqf_destroy (YAZ_PQF_Parser p);
59 Z_RPNQuery *yaz_pqf_parse (YAZ_PQF_Parser p, ODR o, const char *qbuf);
61 Z_AttributesPlusTerm *yaz_pqf_scan (YAZ_PQF_Parser p, ODR o,
62 Odr_oid **attributeSetId, const char *qbuf);
65 int yaz_pqf_error (YAZ_PQF_Parser p, const char **msg, size_t *off);
68 A PQF parser is created and destructed by functions
69 <function>yaz_pqf_create</function> and
70 <function>yaz_pqf_destroy</function> respectively.
71 Function <function>yaz_pqf_parse</function> parses query given
72 by string <literal>qbuf</literal>. If parsing was successful,
73 a Z39.50 RPN Query is returned which is created using ODR stream
74 <literal>o</literal>. If parsing failed, a NULL pointer is
76 Function <function>yaz_pqf_scan</function> takes a scan query in
77 <literal>qbuf</literal>. If parsing was successful, the function
78 returns attributes plus term pointer and modifies
79 <literal>attributeSetId</literal> to hold attribute set for the
80 scan request - both allocated using ODR stream <literal>o</literal>.
81 If parsing failed, yaz_pqf_scan returns a NULL pointer.
82 Error information for bad queries can be obtained by a call to
83 <function>yaz_pqf_error</function> which returns an error code and
84 modifies <literal>*msg</literal> to point to an error description,
85 and modifies <literal>*off</literal> to the offset within last
86 query were parsing failed.
89 The second set of functions are declared as follows:
92 #include <yaz/pquery.h>
94 Z_RPNQuery *p_query_rpn (ODR o, oid_proto proto, const char *qbuf);
96 Z_AttributesPlusTerm *p_query_scan (ODR o, oid_proto proto,
97 Odr_oid **attributeSetP, const char *qbuf);
99 int p_query_attset (const char *arg);
102 The function <function>p_query_rpn()</function> takes as arguments an
103 &odr; stream (see section <link linkend="odr">The ODR Module</link>)
104 to provide a memory source (the structure created is released on
105 the next call to <function>odr_reset()</function> on the stream), a
106 protocol identifier (one of the constants <token>PROTO_Z3950</token> and
107 <token>PROTO_SR</token>), an attribute set reference, and
108 finally a null-terminated string holding the query string.
111 If the parse went well, <function>p_query_rpn()</function> returns a
112 pointer to a <literal>Z_RPNQuery</literal> structure which can be
113 placed directly into a <literal>Z_SearchRequest</literal>.
114 If parsing failed, due to syntax error, a NULL pointer is returned.
117 The <literal>p_query_attset</literal> specifies which attribute set
118 to use if the query doesn't specify one by the
119 <literal>@attrset</literal> operator.
120 The <literal>p_query_attset</literal> returns 0 if the argument is a
121 valid attribute set specifier; otherwise the function returns -1.
125 The grammar of the PQF is as follows:
129 query ::= top-set query-struct.
131 top-set ::= [ '@attrset' string ]
133 query-struct ::= attr-spec | simple | complex | '@term' term-type query
135 attr-spec ::= '@attr' [ string ] string query-struct
137 complex ::= operator query-struct query-struct.
139 operator ::= '@and' | '@or' | '@not' | '@prox' proximity.
141 simple ::= result-set | term.
143 result-set ::= '@set' string.
147 proximity ::= exclusion distance ordered relation which-code unit-code.
149 exclusion ::= '1' | '0' | 'void'.
151 distance ::= integer.
153 ordered ::= '1' | '0'.
155 relation ::= integer.
157 which-code ::= 'known' | 'private' | integer.
159 unit-code ::= integer.
161 term-type ::= 'general' | 'numeric' | 'string' | 'oid' | 'datetime' | 'null'.
165 You will note that the syntax above is a fairly faithful
166 representation of RPN, except for the Attribute, which has been
167 moved a step away from the term, allowing you to associate one or more
168 attributes with an entire query structure. The parser will
169 automatically apply the given attributes to each term as required.
173 The @attr operator is followed by an attribute specification
174 (<literal>attr-spec</literal> above). The specification consists
175 of an optional attribute set, an attribute type-value pair and
176 a sub-query. The attribute type-value pair is packed in one string:
177 an attribute type, an equals sign, and an attribute value, like this:
178 <literal>@attr 1=1003</literal>.
179 The type is always an integer but the value may be either an
180 integer or a string (if it doesn't start with a digit character).
181 A string attribute-value is encoded as a Type-1 ``complex''
182 attribute with the list of values containing the single string
183 specified, and including no semantic indicators.
187 Version 3 of the Z39.50 specification defines various encoding of terms.
188 Use <literal>@term </literal> <replaceable>type</replaceable>
189 <replaceable>string</replaceable>,
190 where type is one of: <literal>general</literal>,
191 <literal>numeric</literal> or <literal>string</literal>
192 (for InternationalString).
193 If no term type has been given, the <literal>general</literal> form
194 is used. This is the only encoding allowed in both versions 2 and 3
195 of the Z39.50 standard.
198 <sect3 id="PQF-prox">
199 <title>Using Proximity Operators with PQF</title>
202 This is an advanced topic, describing how to construct
203 queries that make very specific requirements on the
204 relative location of their operands.
205 You may wish to skip this section and go straight to
206 <link linkend="pqf-examples">the example PQF queries</link>.
211 Most Z39.50 servers do not support proximity searching, or
212 support only a small subset of the full functionality that
213 can be expressed using the PQF proximity operator. Be
214 aware that the ability to <emphasis>express</emphasis> a
215 query in PQF is no guarantee that any given server will
216 be able to <emphasis>execute</emphasis> it.
222 The proximity operator <literal>@prox</literal> is a special
223 and more restrictive version of the conjunction operator
224 <literal>@and</literal>. Its semantics are described in
225 section 3.7.2 (Proximity) of Z39.50 the standard itself, which
226 can be read on-line at
227 <ulink url="&url.z39.50.proximity;"/>
230 In PQF, the proximity operation is represented by a sequence
233 @prox <replaceable>exclusion</replaceable> <replaceable>distance</replaceable> <replaceable>ordered</replaceable> <replaceable>relation</replaceable> <replaceable>which-code</replaceable> <replaceable>unit-code</replaceable>
235 in which the meanings of the parameters are as described in in
236 the standard, and they can take the following values:
238 <listitem><formalpara><title>exclusion</title><para>
239 0 = false (i.e. the proximity condition specified by the
240 remaining parameters must be satisfied) or
241 1 = true (the proximity condition specified by the
242 remaining parameters must <emphasis>not</emphasis> be
244 </para></formalpara></listitem>
245 <listitem><formalpara><title>distance</title><para>
246 An integer specifying the difference between the locations
247 of the operands: e.g. two adjacent words would have
248 distance=1 since their locations differ by one unit.
249 </para></formalpara></listitem>
250 <listitem><formalpara><title>ordered</title><para>
251 1 = ordered (the operands must occur in the order the
252 query specifies them) or
253 0 = unordered (they may appear in either order).
254 </para></formalpara></listitem>
255 <listitem><formalpara><title>relation</title><para>
256 Recognised values are
260 4 (greaterThanOrEqual),
263 </para></formalpara></listitem>
264 <listitem><formalpara><title>which-code</title><para>
265 <literal>known</literal>
268 (the unit-code parameter is taken from the well-known list
269 of alternatives described in below) or
270 <literal>private</literal>
273 (the unit-code paramater has semantics specific to an
274 out-of-band agreement such as a profile).
275 </para></formalpara></listitem>
276 <listitem><formalpara><title>unit-code</title><para>
277 If the which-code parameter is <literal>known</literal>
278 then the recognised values are
290 If which-code is <literal>private</literal> then the
291 acceptable values are determined by the profile.
292 </para></formalpara></listitem>
294 (The numeric values of the relation and well-known unit-code
295 parameters are taken straight from
296 <ulink url="&url.z39.50.proximity.asn1;"
297 >the ASN.1</ulink> of the proximity structure in the standard.)
301 <sect3 id="pqf-examples"><title>PQF queries</title>
303 <example id="example.pqf.simple.terms">
304 <title>PQF queries using simple terms</title>
313 <example id="pqf.example.pqf.boolean.operators">
314 <title>PQF boolean operators</title>
317 @or "dylan" "zimmerman"
319 @and @or dylan zimmerman when
321 @and when @or dylan zimmerman
325 <example id="example.pqf.result.sets">
326 <title>PQF references to result sets</title>
331 @and @set seta @set setb
335 <example id="example.pqf.attributes">
336 <title>Attributes for terms</title>
341 @attr 1=4 @attr 4=1 "self portrait"
343 @attrset exp1 @attr 1=1 CategoryList
345 @attr gils 1=2008 Copenhagen
347 @attr 1=/book/title computer
351 <example id="example.pqf.proximity">
352 <title>PQF Proximity queries</title>
355 @prox 0 3 1 2 k 2 dylan zimmerman
358 Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
359 distance, ordered, relation, which-code and unit-code, in that
363 exclusion = 0: the proximity condition must hold
366 distance = 3: the terms must be three units apart
369 ordered = 1: they must occur in the order they are specified
372 relation = 2: lessThanOrEqual (to the distance of 3 units)
375 which-code is ``known'', so the standard unit-codes are used
381 So the whole proximity query means that the words
382 <literal>dylan</literal> and <literal>zimmerman</literal> must
383 both occur in the record, in that order, differing in position
384 by three or fewer words (i.e. with two or fewer words between
385 them.) The query would find ``Bob Dylan, aka. Robert
386 Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
387 since the distance in this case is four.
391 <example id="example.pqf.search.term.type">
392 <title>PQF specification of search term type</title>
395 @term string "a UTF-8 string, maybe?"
399 <example id="example.pqf.mixed.queries">
400 <title>PQF mixed queries</title>
403 @or @and bob dylan @set Result-1
405 @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
407 @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
411 The last of these examples is a spatial search: in
412 <ulink url="http://www.gils.net/prof_v2.html#sec_7_4"
413 >the GILS attribute set</ulink>,
415 2038 indicates West Bounding Coordinate and
416 2030 indicates East Bounding Coordinate,
417 so the query is for areas extending from -114 degrees
418 to no more than -109 degrees.
425 <sect2 id="CCL"><title>CCL</title>
428 Not all users enjoy typing in prefix query structures and numerical
429 attribute values, even in a minimalistic test client. In the library
430 world, the more intuitive Common Command Language - CCL (ISO 8777)
431 has enjoyed some popularity - especially before the widespread
432 availability of graphical interfaces. It is still useful in
433 applications where you for some reason or other need to provide a
434 symbolic language for expressing boolean query structures.
437 <sect3 id="ccl.syntax">
438 <title>CCL Syntax</title>
441 The CCL parser obeys the following grammar for the FIND argument.
442 The syntax is annotated by in the lines prefixed by
443 <literal>--</literal>.
447 CCL-Find ::= CCL-Find Op Elements
450 Op ::= "and" | "or" | "not"
451 -- The above means that Elements are separated by boolean operators.
453 Elements ::= '(' CCL-Find ')'
456 | Qualifiers Relation Terms
457 | Qualifiers Relation '(' CCL-Find ')'
458 | Qualifiers '=' string '-' string
459 -- Elements is either a recursive definition, a result set reference, a
460 -- list of terms, qualifiers followed by terms, qualifiers followed
461 -- by a recursive definition or qualifiers in a range (lower - upper).
463 Set ::= 'set' = string
464 -- Reference to a result set
466 Terms ::= Terms Prox Term
468 -- Proximity of terms.
472 -- This basically means that a term may include a blank
474 Qualifiers ::= Qualifiers ',' string
476 -- Qualifiers is a list of strings separated by comma
478 Relation ::= '=' | '>=' | '<=' | '<>' | '>' | '<'
479 -- Relational operators. This really doesn't follow the ISO8777
483 -- Proximity operator
487 <example id="example.ccl.queries">
488 <title>CCL queries</title>
490 The following queries are all valid:
502 (dylan and bob) or set=1
512 Assuming that the qualifiers <literal>ti</literal>,
513 <literal>au</literal>
514 and <literal>date</literal> are defined we may use:
520 au=(bob dylan and slow train coming)
522 date>1980 and (ti=((self portrait)))
528 <sect3 id="ccl.qualifiers">
529 <title>CCL Qualifiers</title>
532 Qualifiers are used to direct the search to a particular searchable
533 index, such as title (ti) and author indexes (au). The CCL standard
534 itself doesn't specify a particular set of qualifiers, but it does
535 suggest a few short-hand notations. You can customize the CCL parser
536 to support a particular set of qualifiers to reflect the current target
537 profile. Traditionally, a qualifier would map to a particular
538 use-attribute within the BIB-1 attribute set. It is also
539 possible to set other attributes, such as the structure
544 A CCL profile is a set of predefined CCL qualifiers that may be
545 read from a file or set in the CCL API.
546 The YAZ client reads its CCL qualifiers from a file named
547 <filename>default.bib</filename>. There are four types of
548 lines in a CCL profile: qualifier specification,
549 qualifier alias, comments and directives.
551 <sect4 id="ccl.qualifier.specification">
552 <title>Qualifier specification</title>
554 A qualifier specification is of the form:
558 <replaceable>qualifier-name</replaceable>
559 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable>
560 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable> ...
564 where <replaceable>qualifier-name</replaceable> is the name of the
565 qualifier to be used (eg. <literal>ti</literal>),
566 <replaceable>type</replaceable> is attribute type in the attribute
567 set (Bib-1 is used if no attribute set is given) and
568 <replaceable>val</replaceable> is attribute value.
569 The <replaceable>type</replaceable> can be specified as an
570 integer or as it be specified either as a single-letter:
571 <literal>u</literal> for use,
572 <literal>r</literal> for relation,<literal>p</literal> for position,
573 <literal>s</literal> for structure,<literal>t</literal> for truncation
574 or <literal>c</literal> for completeness.
575 The attributes for the special qualifier name <literal>term</literal>
576 are used when no CCL qualifier is given in a query.
577 <table id="ccl.common.bib1.attributes">
578 <title>Common Bib-1 attributes</title>
580 <colspec colwidth="2*" colname="type"></colspec>
581 <colspec colwidth="9*" colname="description"></colspec>
585 <entry>Description</entry>
590 <entry><literal>u=</literal><replaceable>value</replaceable></entry>
592 Use attribute (1). Common use attributes are
593 1 Personal-name, 4 Title, 7 ISBN, 8 ISSN, 30 Date,
594 62 Subject, 1003 Author), 1016 Any. Specify value
600 <entry><literal>r=</literal><replaceable>value</replaceable></entry>
602 Relation attribute (2). Common values are
603 1 <, 2 <=, 3 =, 4 >=, 5 >, 6 <>,
604 100 phonetic, 101 stem, 102 relevance, 103 always matches.
609 <entry><literal>p=</literal><replaceable>value</replaceable></entry>
611 Position attribute (3). Values: 1 first in field, 2
612 first in any subfield, 3 any position in field.
617 <entry><literal>s=</literal><replaceable>value</replaceable></entry>
619 Structure attribute (4). Values: 1 phrase, 2 word,
620 3 key, 4 year, 5 date, 6 word list, 100 date (un),
621 101 name (norm), 102 name (un), 103 structure, 104 urx,
622 105 free-form-text, 106 document-text, 107 local-number,
623 108 string, 109 numeric string.
628 <entry><literal>t=</literal><replaceable>value</replaceable></entry>
630 Truncation attribute (5). Values: 1 right, 2 left,
631 3 left& right, 100 none, 101 process #, 102 regular-1,
632 103 regular-2, 104 CCL.
637 <entry><literal>c=</literal><replaceable>value</replaceable></entry>
639 Completeness attribute (6). Values: 1 incomplete subfield,
640 2 complete subfield, 3 complete field.
649 Refer to <xref linkend="bib1"/> or the complete
650 <ulink url="&url.z39.50.attset.bib1;">list of Bib-1 attributes</ulink>
653 It is also possible to specify non-numeric attribute values,
654 which are used in combination with certain types.
655 The special combinations are:
657 <table id="ccl.special.attribute.combos">
658 <title>Special attribute combos</title>
660 <colspec colwidth="2*" colname="name"></colspec>
661 <colspec colwidth="9*" colname="description"></colspec>
665 <entry>Description</entry>
670 <entry><literal>s=pw</literal></entry><entry>
671 The structure is set to either word or phrase depending
672 on the number of tokens in a term (phrase-word).
676 <entry><literal>s=al</literal></entry><entry>
677 Each token in the term is ANDed. (and-list).
678 This does not set the structure at all.
682 <row><entry><literal>s=ol</literal></entry><entry>
683 Each token in the term is ORed. (or-list).
684 This does not set the structure at all.
688 <row><entry><literal>s=ag</literal></entry><entry>
689 Tokens that appears as phrases (with blank in them) gets
690 structure phrase attached. Tokens that appers as words
691 gets structure phrase attached. Phrases and words are
692 ANDed. This is a variant of s=al and s=pw, with the main
693 difference that words are not split (with operator AND)
694 but instead kept in one RPN token. This facility appeared
699 <row><entry><literal>r=o</literal></entry><entry>
700 Allows ranges and the operators greather-than, less-than, ...
702 This sets Bib-1 relation attribute accordingly (relation
703 ordered). A query construct is only treated as a range if
704 dash is used and that is surrounded by white-space. So
705 <literal>-1980</literal> is treated as term
706 <literal>"-1980"</literal> not <literal><= 1980</literal>.
707 If <literal>- 1980</literal> is used, however, that is
712 <row><entry><literal>r=r</literal></entry><entry>
713 Similar to <literal>r=o</literal> but assumes that terms
714 are non-negative (not prefixed with <literal>-</literal>).
715 Thus, a dash will always be treated as a range.
716 The construct <literal>1980-1990</literal> is
717 treated as a range with <literal>r=r</literal> but as a
718 single term <literal>"1980-1990"</literal> with
719 <literal>r=o</literal>. The special attribute
720 <literal>r=r</literal> is available in YAZ 2.0.24 or later.
724 <row><entry><literal>t=l</literal></entry><entry>
725 Allows term to be left-truncated.
726 If term is of the form <literal>?x</literal>, the resulting
727 Type-1 term is <literal>x</literal> and truncation is left.
731 <row><entry><literal>t=r</literal></entry><entry>
732 Allows term to be right-truncated.
733 If term is of the form <literal>x?</literal>, the resulting
734 Type-1 term is <literal>x</literal> and truncation is right.
738 <row><entry><literal>t=n</literal></entry><entry>
739 If term is does not include <literal>?</literal>, the
740 truncation attribute is set to none (100).
744 <row><entry><literal>t=b</literal></entry><entry>
745 Allows term to be both left&right truncated.
746 If term is of the form <literal>?x?</literal>, the
747 resulting term is <literal>x</literal> and trunctation is
748 set to both left&right.
752 <row><entry><literal>t=x</literal></entry><entry>
753 Allows masking anywhere in a term, thus fully supporting
754 # (mask one character) and ? (zero or more of any).
755 If masking is used, trunction is set to 102 (regexp-1 in term)
756 and the term is converted accordingly to a regular expression.
760 <row><entry><literal>t=z</literal></entry><entry>
761 Allows masking anywhere in a term, thus fully supporting
762 # (mask one character) and ? (zero or more of any).
763 If masking is used, trunction is set to 104 (Z39.58 in term)
764 and the term is converted accordingly to Z39.58 masking term -
765 actually the same truncation as CCL itself.
773 <example id="example.ccl.profile"><title>CCL profile</title>
775 Consider the following definition:
786 <literal>ti</literal> and <literal>au</literal> both set
787 structure attribute to phrase (s=1).
788 <literal>ti</literal>
789 sets the use-attribute to 4. <literal>au</literal> sets the
791 When no qualifiers are used in the query the structure-attribute is
792 set to free-form-text (105) (rule for <literal>term</literal>).
793 The <literal>date</literal> sets the relation attribute to
794 the relation used in the CCL query and sets the use attribute
798 You can combine attributes. To Search for "ranked title" you
801 ti,ranked=knuth computer
803 which will set relation=ranked, use=title, structure=phrase.
810 is a valid query. But
818 <sect4 id="ccl.qualifier.alias">
819 <title>Qualifier alias</title>
821 A qualifier alias is of the form:
824 <replaceable>q</replaceable>
825 <replaceable>q1</replaceable> <replaceable>q2</replaceable> ..
828 which declares <replaceable>q</replaceable> to
829 be an alias for <replaceable>q1</replaceable>,
830 <replaceable>q2</replaceable>... such that the CCL
831 query <replaceable>q=x</replaceable> is equivalent to
832 <replaceable>q1=x or q2=x or ...</replaceable>.
836 <sect4 id="ccl.comments">
837 <title>Comments</title>
839 Lines with white space or lines that begin with
840 character <literal>#</literal> are treated as comments.
844 <sect4 id="ccl.directives">
845 <title>Directives</title>
847 Directive specifications takes the form
849 <para><literal>@</literal><replaceable>directive</replaceable> <replaceable>value</replaceable>
851 <table id="ccl.directives.table">
852 <title>CCL directives</title>
854 <colspec colwidth="2*" colname="name"></colspec>
855 <colspec colwidth="8*" colname="description"></colspec>
856 <colspec colwidth="1*" colname="default"></colspec>
860 <entry>Description</entry>
861 <entry>Default</entry>
866 <entry>truncation</entry>
867 <entry>Truncation character</entry>
868 <entry><literal>?</literal></entry>
872 <entry>Specifies how multiple fields are to be
873 combined. There are two modes: <literal>or</literal>:
874 multiple qualifier fields are ORed,
875 <literal>merge</literal>: attributes for the qualifier
876 fields are merged and assigned to one term.
878 <entry><literal>merge</literal></entry>
882 <entry>Specifies if CCL operators and qualifiers should be
883 compared with case sensitivity or not. Specify 1 for
884 case sensitive; 0 for case insensitive.</entry>
885 <entry><literal>1</literal></entry>
890 <entry>Specifies token for CCL operator AND.</entry>
891 <entry><literal>and</literal></entry>
896 <entry>Specifies token for CCL operator OR.</entry>
897 <entry><literal>or</literal></entry>
902 <entry>Specifies token for CCL operator NOT.</entry>
903 <entry><literal>not</literal></entry>
908 <entry>Specifies token for CCL operator SET.</entry>
909 <entry><literal>set</literal></entry>
917 <title>CCL API</title>
919 All public definitions can be found in the header file
920 <filename>ccl.h</filename>. A profile identifier is of type
921 <literal>CCL_bibset</literal>. A profile must be created with the call
922 to the function <function>ccl_qual_mk</function> which returns a profile
923 handle of type <literal>CCL_bibset</literal>.
927 To read a file containing qualifier definitions the function
928 <function>ccl_qual_file</function> may be convenient. This function
929 takes an already opened <literal>FILE</literal> handle pointer as
930 argument along with a <literal>CCL_bibset</literal> handle.
934 To parse a simple string with a FIND query use the function
937 struct ccl_rpn_node *ccl_find_str (CCL_bibset bibset, const char *str,
938 int *error, int *pos);
941 which takes the CCL profile (<literal>bibset</literal>) and query
942 (<literal>str</literal>) as input. Upon successful completion the RPN
943 tree is returned. If an error occur, such as a syntax error, the integer
944 pointed to by <literal>error</literal> holds the error code and
945 <literal>pos</literal> holds the offset inside query string in which
950 An English representation of the error may be obtained by calling
951 the <literal>ccl_err_msg</literal> function. The error codes are
952 listed in <filename>ccl.h</filename>.
956 To convert the CCL RPN tree (type
957 <literal>struct ccl_rpn_node *</literal>)
958 to the Z_RPNQuery of YAZ the function <function>ccl_rpn_query</function>
959 must be used. This function which is part of YAZ is implemented in
960 <filename>yaz-ccl.c</filename>.
961 After calling this function the CCL RPN tree is probably no longer
962 needed. The <literal>ccl_rpn_delete</literal> destroys the CCL RPN tree.
966 A CCL profile may be destroyed by calling the
967 <function>ccl_qual_rm</function> function.
971 The token names for the CCL operators may be changed by setting the
972 globals (all type <literal>char *</literal>)
973 <literal>ccl_token_and</literal>, <literal>ccl_token_or</literal>,
974 <literal>ccl_token_not</literal> and <literal>ccl_token_set</literal>.
975 An operator may have aliases, i.e. there may be more than one name for
976 the operator. To do this, separate each alias with a space character.
980 <sect2 id="cql"><title>CQL</title>
982 <ulink url="&url.cql;">CQL</ulink>
983 - Common Query Language - was defined for the
984 <ulink url="&url.sru;">SRU</ulink> protocol.
985 In many ways CQL has a similar syntax to CCL.
986 The objective of CQL is different. Where CCL aims to be
987 an end-user language, CQL is <emphasis>the</emphasis> protocol
988 query language for SRU.
992 If you are new to CQL, read the
993 <ulink url="&url.cql.intro;">Gentle Introduction</ulink>.
997 The CQL parser in &yaz; provides the following:
1001 It parses and validates a CQL query.
1006 It generates a C structure that allows you to convert
1007 a CQL query to some other query language, such as SQL.
1012 The parser converts a valid CQL query to PQF, thus providing a
1013 way to use CQL for both SRU servers and Z39.50 targets at the
1019 The parser converts CQL to
1020 <ulink url="&url.xcql;">XCQL</ulink>.
1021 XCQL is an XML representation of CQL.
1022 XCQL is part of the SRU specification. However, since SRU
1023 supports CQL only, we don't expect XCQL to be widely used.
1024 Furthermore, CQL has the advantage over XCQL that it is
1030 <sect3 id="cql.parsing"><title>CQL parsing</title>
1032 A CQL parser is represented by the <literal>CQL_parser</literal>
1033 handle. Its contents should be considered &yaz; internal (private).
1035 #include <yaz/cql.h>
1037 typedef struct cql_parser *CQL_parser;
1039 CQL_parser cql_parser_create(void);
1040 void cql_parser_destroy(CQL_parser cp);
1042 A parser is created by <function>cql_parser_create</function> and
1043 is destroyed by <function>cql_parser_destroy</function>.
1046 To parse a CQL query string, the following function
1049 int cql_parser_string(CQL_parser cp, const char *str);
1051 A CQL query is parsed by the <function>cql_parser_string</function>
1052 which takes a query <parameter>str</parameter>.
1053 If the query was valid (no syntax errors), then zero is returned;
1054 otherwise -1 is returned to indicate a syntax error.
1058 int cql_parser_stream(CQL_parser cp,
1059 int (*getbyte)(void *client_data),
1060 void (*ungetbyte)(int b, void *client_data),
1063 int cql_parser_stdio(CQL_parser cp, FILE *f);
1065 The functions <function>cql_parser_stream</function> and
1066 <function>cql_parser_stdio</function> parses a CQL query
1067 - just like <function>cql_parser_string</function>.
1068 The only difference is that the CQL query can be
1069 fed to the parser in different ways.
1070 The <function>cql_parser_stream</function> uses a generic
1071 byte stream as input. The <function>cql_parser_stdio</function>
1072 uses a <literal>FILE</literal> handle which is opened for reading.
1076 <sect3 id="cql.tree"><title>CQL tree</title>
1078 The the query string is valid, the CQL parser
1079 generates a tree representing the structure of the
1084 struct cql_node *cql_parser_result(CQL_parser cp);
1086 <function>cql_parser_result</function> returns the
1087 a pointer to the root node of the resulting tree.
1090 Each node in a CQL tree is represented by a
1091 <literal>struct cql_node</literal>.
1092 It is defined as follows:
1094 #define CQL_NODE_ST 1
1095 #define CQL_NODE_BOOL 2
1105 struct cql_node *modifiers;
1109 struct cql_node *left;
1110 struct cql_node *right;
1111 struct cql_node *modifiers;
1116 There are two node types: search term (ST) and boolean (BOOL).
1117 A modifier is treated as a search term too.
1120 The search term node has five members:
1124 <literal>index</literal>: index for search term.
1125 If an index is unspecified for a search term,
1126 <literal>index</literal> will be NULL.
1131 <literal>index_uri</literal>: index URi for search term
1132 or NULL if none could be resolved for the index.
1137 <literal>term</literal>: the search term itself.
1142 <literal>relation</literal>: relation for search term.
1147 <literal>relation_uri</literal>: relation URI for search term.
1152 <literal>modifiers</literal>: relation modifiers for search
1153 term. The <literal>modifiers</literal> list itself of cql_nodes
1154 each of type <literal>ST</literal>.
1161 The boolean node represents both <literal>and</literal>,
1162 <literal>or</literal>, not as well as
1167 <literal>left</literal> and <literal>right</literal>: left
1168 - and right operand respectively.
1173 <literal>modifiers</literal>: proximity arguments.
1180 <sect3 id="cql.to.pqf"><title>CQL to PQF conversion</title>
1182 Conversion to PQF (and Z39.50 RPN) is tricky by the fact
1183 that the resulting RPN depends on the Z39.50 target
1184 capabilities (combinations of supported attributes).
1185 In addition, the CQL and SRU operates on index prefixes
1186 (URI or strings), whereas the RPN uses Object Identifiers
1190 The CQL library of &yaz; defines a <literal>cql_transform_t</literal>
1191 type. It represents a particular mapping between CQL and RPN.
1192 This handle is created and destroyed by the functions:
1194 cql_transform_t cql_transform_open_FILE (FILE *f);
1195 cql_transform_t cql_transform_open_fname(const char *fname);
1196 void cql_transform_close(cql_transform_t ct);
1198 The first two functions create a tranformation handle from
1199 either an already open FILE or from a filename respectively.
1202 The handle is destroyed by <function>cql_transform_close</function>
1203 in which case no further reference of the handle is allowed.
1206 When a <literal>cql_transform_t</literal> handle has been created
1207 you can convert to RPN.
1209 int cql_transform_buf(cql_transform_t ct,
1210 struct cql_node *cn, char *out, int max);
1212 This function converts the CQL tree <literal>cn</literal>
1213 using handle <literal>ct</literal>.
1214 For the resulting PQF, you supply a buffer <literal>out</literal>
1215 which must be able to hold at at least <literal>max</literal>
1219 If conversion failed, <function>cql_transform_buf</function>
1220 returns a non-zero SRU error code; otherwise zero is returned
1221 (conversion successful). The meanings of the numeric error
1222 codes are listed in the SRU specifications at
1223 <ulink url="&url.sru.diagnostics.list;"/>
1226 If conversion fails, more information can be obtained by calling
1228 int cql_transform_error(cql_transform_t ct, char **addinfop);
1230 This function returns the most recently returned numeric
1231 error-code and sets the string-pointer at
1232 <literal>*addinfop</literal> to point to a string containing
1233 additional information about the error that occurred: for
1234 example, if the error code is 15 (``Illegal or unsupported context
1235 set''), the additional information is the name of the requested
1236 context set that was not recognised.
1239 The SRU error-codes may be translated into brief human-readable
1240 error messages using
1242 const char *cql_strerror(int code);
1246 If you wish to be able to produce a PQF result in a different
1247 way, there are two alternatives.
1249 void cql_transform_pr(cql_transform_t ct,
1250 struct cql_node *cn,
1251 void (*pr)(const char *buf, void *client_data),
1254 int cql_transform_FILE(cql_transform_t ct,
1255 struct cql_node *cn, FILE *f);
1257 The former function produces output to a user-defined
1258 output stream. The latter writes the result to an already
1259 open <literal>FILE</literal>.
1262 <sect3 id="cql.to.rpn">
1263 <title>Specification of CQL to RPN mappings</title>
1265 The file supplied to functions
1266 <function>cql_transform_open_FILE</function>,
1267 <function>cql_transform_open_fname</function> follows
1268 a structure found in many Unix utilities.
1269 It consists of mapping specifications - one per line.
1270 Lines starting with <literal>#</literal> are ignored (comments).
1273 Each line is of the form
1275 <replaceable>CQL pattern</replaceable><literal> = </literal> <replaceable> RPN equivalent</replaceable>
1279 An RPN pattern is a simple attribute list. Each attribute pair
1282 [<replaceable>set</replaceable>] <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>
1284 The attribute <replaceable>set</replaceable> is optional.
1285 The <replaceable>type</replaceable> is the attribute type,
1286 <replaceable>value</replaceable> the attribute value.
1289 The character <literal>*</literal> (asterisk) has special meaning
1290 when used in the RPN pattern.
1291 Each occurrence of <literal>*</literal> is substituted with the
1292 CQL matching name (index, relation, qualifier etc).
1293 This facility can be used to copy a CQL name verbatim to the RPN result.
1296 The following CQL patterns are recognized:
1298 <varlistentry><term>
1299 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
1303 This pattern is invoked when a CQL index, such as
1304 dc.title is converted. <replaceable>set</replaceable>
1305 and <replaceable>name</replaceable> are the context set and index
1307 Typically, the RPN specifies an equivalent use attribute.
1310 For terms not bound by an index the pattern
1311 <literal>index.cql.serverChoice</literal> is used.
1312 Here, the prefix <literal>cql</literal> is defined as
1313 <literal>http://www.loc.gov/zing/cql/cql-indexes/v1.0/</literal>.
1314 If this pattern is not defined, the mapping will fail.
1318 <literal>index.</literal><replaceable>set</replaceable><literal>.*</literal>
1319 is used when no other index pattern is matched.
1323 <varlistentry><term>
1324 <literal>qualifier.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
1329 For backwards compatibility, this is recognised as a synonym of
1330 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
1334 <varlistentry><term>
1335 <literal>relation.</literal><replaceable>relation</replaceable>
1339 This pattern specifies how a CQL relation is mapped to RPN.
1340 <replaceable>pattern</replaceable> is name of relation
1341 operator. Since <literal>=</literal> is used as
1342 separator between CQL pattern and RPN, CQL relations
1343 including <literal>=</literal> cannot be
1344 used directly. To avoid a conflict, the names
1345 <literal>ge</literal>,
1346 <literal>eq</literal>,
1347 <literal>le</literal>,
1348 must be used for CQL operators, greater-than-or-equal,
1349 equal, less-than-or-equal respectively.
1350 The RPN pattern is supposed to include a relation attribute.
1353 For terms not bound by a relation, the pattern
1354 <literal>relation.scr</literal> is used. If the pattern
1355 is not defined, the mapping will fail.
1358 The special pattern, <literal>relation.*</literal> is used
1359 when no other relation pattern is matched.
1364 <varlistentry><term>
1365 <literal>relationModifier.</literal><replaceable>mod</replaceable>
1369 This pattern specifies how a CQL relation modifier is mapped to RPN.
1370 The RPN pattern is usually a relation attribute.
1375 <varlistentry><term>
1376 <literal>structure.</literal><replaceable>type</replaceable>
1380 This pattern specifies how a CQL structure is mapped to RPN.
1381 Note that this CQL pattern is somewhat to similar to
1382 CQL pattern <literal>relation</literal>.
1383 The <replaceable>type</replaceable> is a CQL relation.
1386 The pattern, <literal>structure.*</literal> is used
1387 when no other structure pattern is matched.
1388 Usually, the RPN equivalent specifies a structure attribute.
1393 <varlistentry><term>
1394 <literal>position.</literal><replaceable>type</replaceable>
1398 This pattern specifies how the anchor (position) of
1399 CQL is mapped to RPN.
1400 The <replaceable>type</replaceable> is one
1401 of <literal>first</literal>, <literal>any</literal>,
1402 <literal>last</literal>, <literal>firstAndLast</literal>.
1405 The pattern, <literal>position.*</literal> is used
1406 when no other position pattern is matched.
1411 <varlistentry><term>
1412 <literal>set.</literal><replaceable>prefix</replaceable>
1416 This specification defines a CQL context set for a given prefix.
1417 The value on the right hand side is the URI for the set -
1418 <emphasis>not</emphasis> RPN. All prefixes used in
1419 index patterns must be defined this way.
1424 <varlistentry><term>
1425 <literal>set</literal>
1429 This specification defines a default CQL context set for index names.
1430 The value on the right hand side is the URI for the set.
1437 <example id="example.cql.to.rpn.mapping">
1438 <title>CQL to RPN mapping file</title>
1440 This simple file defines two context sets, three indexes and three
1441 relations, a position pattern and a default structure.
1443 <programlisting><![CDATA[
1444 set.cql = http://www.loc.gov/zing/cql/context-sets/cql/v1.1/
1445 set.dc = http://www.loc.gov/zing/cql/dc-indexes/v1.0/
1447 index.cql.serverChoice = 1=1016
1448 index.dc.title = 1=4
1449 index.dc.subject = 1=21
1455 position.any = 3=3 6=1
1461 With the mappings above, the CQL query
1465 is converted to the PQF:
1467 @attr 1=1016 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "computer"
1469 by rules <literal>index.cql.serverChoice</literal>,
1470 <literal>relation.scr</literal>, <literal>structure.*</literal>,
1471 <literal>position.any</literal>.
1478 is rejected, since <literal>position.right</literal> is
1484 >my = "http://www.loc.gov/zing/cql/dc-indexes/v1.0/" my.title = x
1488 @attr 1=4 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "x"
1492 <example id="example.cql.to.rpn.string">
1493 <title>CQL to RPN string attributes</title>
1495 In this example we allow any index to be passed to RPN as
1498 <programlisting><![CDATA[
1499 # Identifiers for prefixes used in this file. (index.*)
1500 set.cql = info:srw/cql-context-set/1/cql-v1.1
1501 set.rpn = http://bogus/rpn
1502 set = http://bogus/rpn
1504 # The default index when none is specified by the query
1505 index.cql.serverChoice = 1=any
1514 The <literal>http://bogus/rpn</literal> context set is also the default
1515 so we can make queries such as
1519 which is converted to
1521 @attr 2=3 @attr 4=1 @attr 3=3 @attr 1=title "a"
1525 <example id="example.cql.to.rpn.bathprofile">
1526 <title>CQL to RPN using Bath Profile</title>
1528 The file <filename>etc/pqf.properties</filename> has mappings from
1529 the Bath Profile and Dublin Core to RPN.
1530 If YAZ is installed as a package it's usually located
1531 in <filename>/usr/share/yaz/etc</filename> and part of the
1532 development package, such as <literal>libyaz-dev</literal>.
1536 <sect3 id="cql.xcql"><title>CQL to XCQL conversion</title>
1538 Conversion from CQL to XCQL is trivial and does not
1539 require a mapping to be defined.
1540 There three functions to choose from depending on the
1541 way you wish to store the resulting output (XML buffer
1544 int cql_to_xml_buf(struct cql_node *cn, char *out, int max);
1545 void cql_to_xml(struct cql_node *cn,
1546 void (*pr)(const char *buf, void *client_data),
1548 void cql_to_xml_stdio(struct cql_node *cn, FILE *f);
1550 Function <function>cql_to_xml_buf</function> converts
1551 to XCQL and stores result in a user supplied buffer of a given
1555 <function>cql_to_xml</function> writes the result in
1556 a user defined output stream.
1557 <function>cql_to_xml_stdio</function> writes to a
1563 <sect1 id="tools.oid"><title>Object Identifiers</title>
1566 The basic YAZ representation of an OID is an array of integers,
1567 terminated with the value -1. This integer is of type
1568 <literal>Odr_oid</literal>.
1571 Fundamental OID operations and the type <literal>Odr_oid</literal>
1572 are defined in <filename>yaz/oid_util.h</filename>.
1575 An OID can either be declared as a automatic variable or it can
1576 allocated using the memory utilities or ODR/NMEM. It's
1577 guaranteed that an OID can fit in <literal>OID_SIZE</literal> integers.
1579 <example id="tools.oid.bib1.1"><title>Create OID on stack</title>
1581 We can create an OID for the Bib-1 attribute set with:
1583 Odr_oid bib1[OID_SIZE];
1595 And OID may also be filled from a string-based representation using
1596 dots (.). This is achieved by function
1598 int oid_dotstring_to_oid(const char *name, Odr_oid *oid);
1600 This functions returns 0 if name could be converted; -1 otherwise.
1602 <example id="tools.oid.bib1.2"><title>Using oid_oiddotstring_to_oid</title>
1604 We can fill the Bib-1 attribute set OID easier with:
1606 Odr_oid bib1[OID_SIZE];
1607 oid_oiddotstring_to_oid("1.2.840.10003.3.1", bib1);
1612 We can also allocate an OID dynamically on a ODR stream with:
1614 Odr_oid *odr_getoidbystr(ODR o, const char *str);
1616 This creates an OID from string-based representation using dots.
1617 This function take an &odr; stream as parameter. This stream is used to
1618 allocate memory for the data elements, which is released on a
1619 subsequent call to <function>odr_reset()</function> on that stream.
1622 <example id="tools.oid.bib1.3"><title>Using odr_getoidbystr</title>
1624 We can create a OID for the Bib-1 attribute set with:
1626 Odr_oid *bib1 = odr_getoidbystr(odr, "1.2.840.10003.3.1");
1634 char *oid_oid_to_dotstring(const Odr_oid *oid, char *oidbuf)
1636 does the reverse of <function>oid_oiddotstring_to_oid</function>. It
1637 converts an OID to the string-based representation using dots.
1638 The supplied char buffer <literal>oidbuf</literal> holds the resulting
1639 string and must be at least <literal>OID_STR_MAX</literal> in size.
1643 OIDs can be copied with <function>oid_oidcpy</function> which takes
1644 two OID lists as arguments. Alternativly, an OID copy can be allocated
1645 on a ODR stream with:
1647 Odr_oid *odr_oiddup(ODR odr, const Odr_oid *o);
1652 OIDs can be compared with <function>oid_oidcmp</function> which returns
1653 zero if the two OIDs provided are identical; non-zero otherwise.
1656 <sect2 id="tools.oid.database"><title>OID database</title>
1658 From YAZ version 3 and later, the oident system has been replaced
1659 by an OID database. OID database is a misnomer .. the old odient
1660 system was also a database.
1663 The OID database is really just a map between named Object Identifiers
1664 (string) and their OID raw equivalents. Most operations either
1665 convert from string to OID or other way around.
1668 Unfortunately, whenever we supply a string we must also specify the
1669 <emphasis>OID class</emphasis>. The class is necessary because some
1670 strings correspond to multiple OIDs. An example of such a string is
1671 <literal>Bib-1</literal> which may either be an attribute-set
1672 or a diagnostic-set.
1675 Applications using the YAZ database should include
1676 <filename>yaz/oid_db.h</filename>.
1679 A YAZ database handle is of type <literal>yaz_oid_db_t</literal>.
1680 Actually that's a pointer. You need not think deal with that.
1681 YAZ has a built-in database which can be considered "constant" for
1683 We can get hold that by using function <function>yaz_oid_std</function>.
1686 All functions with prefix <function>yaz_string_to_oid</function>
1687 converts from class + string to OID. We have variants of this
1688 operation due to different memory allocation strategies.
1691 All functions with prefix
1692 <function>yaz_oid_to_string</function> converts from OID to string
1696 <example id="tools.oid.bib1.4"><title>Create OID with YAZ DB</title>
1698 We can create an OID for the Bib-1 attribute set on the ODR stream
1702 yaz_string_to_oid_odr(yaz_oid_std(), CLASS_ATTSET, "Bib-1", odr);
1704 This is more complex than using <function>odr_getoidbystr</function>.
1705 You would only use <function>yaz_string_to_oid_odr</function> when the
1706 string (here Bib-1) is supplied by a user or configuration.
1711 <sect2 id="tools.oid.std"><title>Standard OIDs</title>
1714 All the object identifers in the standard OID database as returned
1715 by <function>yaz_oid_std</function> can referenced directly in a
1716 program as a constant OID.
1717 Each constant OID is prefixed with <literal>yaz_oid_</literal> -
1718 followed by OID class (lowercase) - then by OID name (normalized and
1722 See <xref linkend="list-oids"/> for list of all object identifiers
1724 These are declared in <filename>yaz/oid_std.h</filename> but are
1725 included by <filename>yaz/oid_db.h</filename> as well.
1728 <example id="tools.oid.bib1.5"><title>Use a built-in OID</title>
1730 We can allocate our own OID filled with the constant OID for
1733 Odr_oid *bib1 = odr_oiddup(o, yaz_oid_attset_bib1);
1739 <sect1 id="tools.nmem"><title>Nibble Memory</title>
1742 Sometimes when you need to allocate and construct a large,
1743 interconnected complex of structures, it can be a bit of a pain to
1744 release the associated memory again. For the structures describing the
1745 Z39.50 PDUs and related structures, it is convenient to use the
1746 memory-management system of the &odr; subsystem (see
1747 <xref linkend="odr.use"/>). However, in some circumstances
1748 where you might otherwise benefit from using a simple nibble memory
1749 management system, it may be impractical to use
1750 <function>odr_malloc()</function> and <function>odr_reset()</function>.
1751 For this purpose, the memory manager which also supports the &odr;
1752 streams is made available in the NMEM module. The external interface
1753 to this module is given in the <filename>nmem.h</filename> file.
1757 The following prototypes are given:
1761 NMEM nmem_create(void);
1762 void nmem_destroy(NMEM n);
1763 void *nmem_malloc(NMEM n, size_t size);
1764 void nmem_reset(NMEM n);
1765 size_t nmem_total(NMEM n);
1766 void nmem_init(void);
1767 void nmem_exit(void);
1771 The <function>nmem_create()</function> function returns a pointer to a
1772 memory control handle, which can be released again by
1773 <function>nmem_destroy()</function> when no longer needed.
1774 The function <function>nmem_malloc()</function> allocates a block of
1775 memory of the requested size. A call to <function>nmem_reset()</function>
1776 or <function>nmem_destroy()</function> will release all memory allocated
1777 on the handle since it was created (or since the last call to
1778 <function>nmem_reset()</function>. The function
1779 <function>nmem_total()</function> returns the number of bytes currently
1780 allocated on the handle.
1784 The nibble memory pool is shared amongst threads. POSIX
1785 mutex'es and WIN32 Critical sections are introduced to keep the
1786 module thread safe. Function <function>nmem_init()</function>
1787 initializes the nibble memory library and it is called automatically
1788 the first time the <literal>YAZ.DLL</literal> is loaded. &yaz; uses
1789 function <function>DllMain</function> to achieve this. You should
1790 <emphasis>not</emphasis> call <function>nmem_init</function> or
1791 <function>nmem_exit</function> unless you're absolute sure what
1792 you're doing. Note that in previous &yaz; versions you'd have to call
1793 <function>nmem_init</function> yourself.
1798 <sect1 id="tools.log"><title>Log</title>
1800 &yaz; has evolved a fairly complex log system which should be useful both
1801 for debugging &yaz; itself, debugging applications that use &yaz;, and for
1802 production use of those applications.
1805 The log functions are declared in header <filename>yaz/log.h</filename>
1806 and implemented in <filename>src/log.c</filename>.
1807 Due to name clash with syslog and some math utilities the logging
1808 interface has been modified as of YAZ 2.0.29. The obsolete interface
1809 is still available if in header file <filename>yaz/log.h</filename>.
1810 The key points of the interface are:
1813 void yaz_log(int level, const char *fmt, ...)
1815 void yaz_log_init(int level, const char *prefix, const char *name);
1816 void yaz_log_init_file(const char *fname);
1817 void yaz_log_init_level(int level);
1818 void yaz_log_init_prefix(const char *prefix);
1819 void yaz_log_time_format(const char *fmt);
1820 void yaz_log_init_max_size(int mx);
1822 int yaz_log_mask_str(const char *str);
1823 int yaz_log_module_level(const char *name);
1827 The reason for the whole log module is the <function>yaz_log</function>
1828 function. It takes a bitmask indicating the log levels, a
1829 <literal>printf</literal>-like format string, and a variable number of
1834 The <literal>log level</literal> is a bit mask, that says on which level(s)
1835 the log entry should be made, and optionally set some behaviour of the
1836 logging. In the most simple cases, it can be one of <literal>YLOG_FATAL,
1837 YLOG_DEBUG, YLOG_WARN, YLOG_LOG</literal>. Those can be combined with bits
1838 that modify the way the log entry is written:<literal>YLOG_ERRNO,
1839 YLOG_NOTIME, YLOG_FLUSH</literal>.
1840 Most of the rest of the bits are deprecated, and should not be used. Use
1841 the dynamic log levels instead.
1845 Applications that use &yaz;, should not use the LOG_LOG for ordinary
1846 messages, but should make use of the dynamic loglevel system. This consists
1847 of two parts, defining the loglevel and checking it.
1851 To define the log levels, the (main) program should pass a string to
1852 <function>yaz_log_mask_str</function> to define which log levels are to be
1853 logged. This string should be a comma-separated list of log level names,
1854 and can contain both hard-coded names and dynamic ones. The log level
1855 calculation starts with <literal>YLOG_DEFAULT_LEVEL</literal> and adds a bit
1856 for each word it meets, unless the word starts with a '-', in which case it
1857 clears the bit. If the string <literal>'none'</literal> is found,
1858 all bits are cleared. Typically this string comes from the command-line,
1859 often identified by <literal>-v</literal>. The
1860 <function>yaz_log_mask_str</function> returns a log level that should be
1861 passed to <function>yaz_log_init_level</function> for it to take effect.
1865 Each module should check what log bits it should be used, by calling
1866 <function>yaz_log_module_level</function> with a suitable name for the
1867 module. The name is cleared from a preceding path and an extension, if any,
1868 so it is quite possible to use <literal>__FILE__</literal> for it. If the
1869 name has been passed to <function>yaz_log_mask_str</function>, the routine
1870 returns a non-zero bitmask, which should then be used in consequent calls
1871 to yaz_log. (It can also be tested, so as to avoid unnecessary calls to
1872 yaz_log, in time-critical places, or when the log entry would take time
1877 Yaz uses the following dynamic log levels:
1878 <literal>server, session, request, requestdetail</literal> for the server
1880 <literal>zoom</literal> for the zoom client api.
1881 <literal>ztest</literal> for the simple test server.
1882 <literal>malloc, nmem, odr, eventl</literal> for internal debugging of yaz itself.
1883 Of course, any program using yaz is welcome to define as many new ones, as
1888 By default the log is written to stderr, but this can be changed by a call
1889 to <function>yaz_log_init_file</function> or
1890 <function>yaz_log_init</function>. If the log is directed to a file, the
1891 file size is checked at every write, and if it exceeds the limit given in
1892 <function>yaz_log_init_max_size</function>, the log is rotated. The
1893 rotation keeps one old version (with a <literal>.1</literal> appended to
1894 the name). The size defaults to 1GB. Setting it to zero will disable the
1899 A typical yaz-log looks like this
1900 13:23:14-23/11 yaz-ztest(1) [session] Starting session from tcp:127.0.0.1 (pid=30968)
1901 13:23:14-23/11 yaz-ztest(1) [request] Init from 'YAZ' (81) (ver 2.0.28) OK
1902 13:23:17-23/11 yaz-ztest(1) [request] Search Z: @attrset Bib-1 foo OK:7 hits
1903 13:23:22-23/11 yaz-ztest(1) [request] Present: [1] 2+2 OK 2 records returned
1904 13:24:13-23/11 yaz-ztest(1) [request] Close OK
1908 The log entries start with a time stamp. This can be omitted by setting the
1909 <literal>YLOG_NOTIME</literal> bit in the loglevel. This way automatic tests
1910 can be hoped to produce identical log files, that are easy to diff. The
1911 format of the time stamp can be set with
1912 <function>yaz_log_time_format</function>, which takes a format string just
1913 like <function>strftime</function>.
1917 Next in a log line comes the prefix, often the name of the program. For
1918 yaz-based servers, it can also contain the session number. Then
1919 comes one or more logbits in square brackets, depending on the logging
1920 level set by <function>yaz_log_init_level</function> and the loglevel
1921 passed to <function>yaz_log_init_level</function>. Finally comes the format
1922 string and additional values passed to <function>yaz_log</function>
1926 The log level <literal>YLOG_LOGLVL</literal>, enabled by the string
1927 <literal>loglevel</literal>, will log all the log-level affecting
1928 operations. This can come in handy if you need to know what other log
1929 levels would be useful. Grep the logfile for <literal>[loglevel]</literal>.
1933 The log system is almost independent of the rest of &yaz;, the only
1934 important dependence is of <filename>nmem</filename>, and that only for
1935 using the semaphore definition there.
1939 The dynamic log levels and log rotation were introduced in &yaz; 2.0.28. At
1940 the same time, the log bit names were changed from
1941 <literal>LOG_something</literal> to <literal>YLOG_something</literal>,
1942 to avoid collision with <filename>syslog.h</filename>.
1947 <sect1 id="marc"><title>MARC</title>
1950 YAZ provides a fast utility for working with MARC records.
1951 Early versions of the MARC utility only allowed decoding of ISO2709.
1952 Today the utility may both encode - and decode to a varity of formats.
1955 #include <yaz/marcdisp.h>
1957 /* create handler */
1958 yaz_marc_t yaz_marc_create(void);
1960 void yaz_marc_destroy(yaz_marc_t mt);
1962 /* set XML mode YAZ_MARC_LINE, YAZ_MARC_SIMPLEXML, ... */
1963 void yaz_marc_xml(yaz_marc_t mt, int xmlmode);
1964 #define YAZ_MARC_LINE 0
1965 #define YAZ_MARC_SIMPLEXML 1
1966 #define YAZ_MARC_OAIMARC 2
1967 #define YAZ_MARC_MARCXML 3
1968 #define YAZ_MARC_ISO2709 4
1969 #define YAZ_MARC_XCHANGE 5
1970 #define YAZ_MARC_CHECK 6
1971 #define YAZ_MARC_TURBOMARC 7
1973 /* supply iconv handle for character set conversion .. */
1974 void yaz_marc_iconv(yaz_marc_t mt, yaz_iconv_t cd);
1976 /* set debug level, 0=none, 1=more, 2=even more, .. */
1977 void yaz_marc_debug(yaz_marc_t mt, int level);
1979 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
1980 On success, result in *result with size *rsize. */
1981 int yaz_marc_decode_buf(yaz_marc_t mt, const char *buf, int bsize,
1982 const char **result, size_t *rsize);
1984 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
1985 On success, result in WRBUF */
1986 int yaz_marc_decode_wrbuf(yaz_marc_t mt, const char *buf,
1987 int bsize, WRBUF wrbuf);
1992 The synopsis is just a basic subset of all functionality. Refer
1993 to the actual header file <filename>marcdisp.h</filename> for
1998 A MARC conversion handle must be created by using
1999 <function>yaz_marc_create</function> and destroyed
2000 by calling <function>yaz_marc_destroy</function>.
2003 All other function operate on a <literal>yaz_marc_t</literal> handle.
2004 The output is specified by a call to <function>yaz_marc_xml</function>.
2005 The <literal>xmlmode</literal> must be one of
2008 <term>YAZ_MARC_LINE</term>
2011 A simple line-by-line format suitable for display but not
2012 recommend for further (machine) processing.
2018 <term>YAZ_MARC_MARCXML</term>
2021 <ulink url="&url.marcxml;">MARCXML</ulink>.
2027 <term>YAZ_MARC_ISO2709</term>
2030 ISO2709 (sometimes just referred to as "MARC").
2036 <term>YAZ_MARC_XCHANGE</term>
2039 <ulink url="&url.marcxchange;">MarcXchange</ulink>.
2045 <term>YAZ_MARC_CHECK</term>
2048 Pseudo format for validation only. Does not generate
2049 any real output except diagnostics.
2055 <term>YAZ_MARC_TURBOMARC</term>
2058 XML format with same semantics as MARCXML but more compact
2059 and geared towards fast processing with XSLT. Refer to
2060 <xref linkend="tools.turbomarc"/> for more information.
2068 The actual conversion functions are
2069 <function>yaz_marc_decode_buf</function> and
2070 <function>yaz_marc_decode_wrbuf</function> which decodes and encodes
2071 a MARC record. The former function operates on simple buffers, the
2072 stores the resulting record in a WRBUF handle (WRBUF is a simple string
2075 <example id="example.marc.display">
2076 <title>Display of MARC record</title>
2078 The following program snippet illustrates how the MARC API may
2079 be used to convert a MARC record to the line-by-line format:
2080 <programlisting><![CDATA[
2081 void print_marc(const char *marc_buf, int marc_buf_size)
2083 char *result; /* for result buf */
2084 size_t result_len; /* for size of result */
2085 yaz_marc_t mt = yaz_marc_create();
2086 yaz_marc_xml(mt, YAZ_MARC_LINE);
2087 yaz_marc_decode_buf(mt, marc_buf, marc_buf_size,
2088 &result, &result_len);
2089 fwrite(result, result_len, 1, stdout);
2090 yaz_marc_destroy(mt); /* note that result is now freed... */
2096 <sect2 id="tools.turbomarc">
2097 <title>TurboMARC</title>
2099 TurboMARC is yet another XML encoding of a MARC record. The format
2100 was designed for fast processing with XSLT.
2104 Pazpar2 uses XSLT to convert an XML encoded MARC record to an internal
2105 representation. This conversion mostly check the tag of a MARC field
2106 to determine the basic rules in the conversion. This check is
2107 costly when that is tag is encoded as an attribute in MARCXML.
2108 By having the tag value as the element instead, makes processing
2109 many times faster (at least for Libxslt).
2112 TurboMARC is encoded as follows:
2115 Record elements is part of namespace
2116 "<literal>http://www.indexdata.com/turbomarc</literal>".
2119 A record is enclosed in element <literal>r</literal>.
2122 A collection of records is enclosed in element
2123 <literal>collection</literal>.
2126 The leader is encoded as element <literal>l</literal> with the
2127 leader content as its (text) value.
2130 A control field is encoded as element <literal>c</literal> concatenated
2131 with the tag value of the control field if the tag value
2132 matches the regular expression <literal>[a-zA-Z0-9]*</literal>.
2133 If the tag value do not match the regular expression
2134 <literal>[a-zA-Z0-9]*</literal> the control field is encoded
2135 as element <literal>c</literal> and attribute <literal>code</literal>
2136 will hold the tag value.
2137 This rule ensure that in the rare cases where a tag value might
2138 result in a non-wellformed XML YAZ encode it as a coded attribute
2142 The control field content is the the text value of this element.
2143 Indicators are encoded as attribute names
2144 <literal>i1</literal>, <literal>i2</literal>, etc.. and
2145 corresponding values for each indicator.
2148 A data field is encoded as element <literal>d</literal> concatenated
2149 with the tag value of the data field or using the attribute
2150 <literal>code</literal> as described in the rules for control fields.
2151 The children of the data field element is subfield elements.
2152 Each subfield element is encoded as <literal>s</literal>
2153 concatenated with the sub field code.
2154 The text of the subfield element is the contents of the subfield.
2155 Indicators are encoded as attributes for the data field element similar
2156 to the encoding for control fields.
2163 <sect1 id="tools.retrieval">
2164 <title>Retrieval Facility</title>
2166 YAZ version 2.1.20 or later includes a Retrieval facility tool
2167 which allows a SRU/Z39.50 to describe itself and perform record
2168 conversions. The idea is the following:
2173 An SRU/Z39.50 client sends a retrieval request which includes
2174 a combination of the following parameters: syntax (format),
2175 schema (or element set name).
2181 The retrieval facility is invoked with parameters in a
2182 server/proxy. The retrieval facility matches the parameters a set of
2183 "supported" retrieval types.
2184 If there is no match, the retrieval signals an error
2185 (syntax and / or schema not supported).
2191 For a successful match, the backend is invoked with the same
2192 or altered retrieval parameters (syntax, schema). If
2193 a record is received from the backend, it is converted to the
2194 frontend name / syntax.
2200 The resulting record is sent back the client and tagged with
2201 the frontend syntax / schema.
2208 The Retrieval facility is driven by an XML configuration. The
2209 configuration is neither Z39.50 ZeeRex or SRU ZeeRex. But it
2210 should be easy to generate both of them from the XML configuration.
2211 (unfortunately the two versions
2212 of ZeeRex differ substantially in this regard).
2214 <sect2 id="tools.retrieval.format">
2215 <title>Retrieval XML format</title>
2217 All elements should be covered by namespace
2218 <literal>http://indexdata.com/yaz</literal> .
2219 The root element node must be <literal>retrievalinfo</literal>.
2222 The <literal>retrievalinfo</literal> must include one or
2223 more <literal>retrieval</literal> elements. Each
2224 <literal>retrieval</literal> defines specific combination of
2225 syntax, name and identifier supported by this retrieval service.
2228 The <literal>retrieval</literal> element may include any of the
2229 following attributes:
2231 <varlistentry><term><literal>syntax</literal> (REQUIRED)</term>
2234 Defines the record syntax. Possible values is any
2235 of the names defined in YAZ' OID database or a raw
2240 <varlistentry><term><literal>name</literal> (OPTIONAL)</term>
2243 Defines the name of the retrieval format. This can be
2244 any string. For SRU, the value, is equivalent to schema (short-hand);
2245 for Z39.50 it's equivalent to simple element set name.
2246 For YAZ 3.0.24 and later this name may be specified as a glob
2247 expression with operators
2248 <literal>*</literal> and <literal>?</literal>.
2252 <varlistentry><term><literal>identifier</literal> (OPTIONAL)</term>
2255 Defines the URI schema name of the retrieval format. This can be
2256 any string. For SRU, the value, is equivalent to URI schema.
2257 For Z39.50, there is no equivalent.
2264 The <literal>retrieval</literal> may include one
2265 <literal>backend</literal> element. If a <literal>backend</literal>
2266 element is given, it specifies how the records are retrieved by
2267 some backend and how the records are converted from the backend to
2271 The attributes, <literal>name</literal> and <literal>syntax</literal>
2272 may be specified for the <literal>backend</literal> element. These
2273 semantics of these attributes is equivalent to those for the
2274 <literal>retrieval</literal>. However, these values are passed to
2278 The <literal>backend</literal> element may includes one or more
2279 conversion instructions (as children elements). The supported
2282 <varlistentry><term><literal>marc</literal></term>
2285 The <literal>marc</literal> element specifies a conversion
2286 to - and from ISO2709 encoded MARC and
2287 <ulink url="&url.marcxml;">&acro.marcxml;</ulink>/MarcXchange.
2288 The following attributes may be specified:
2291 <varlistentry><term><literal>inputformat</literal> (REQUIRED)</term>
2294 Format of input. Supported values are
2295 <literal>marc</literal> (for ISO2709); and <literal>xml</literal>
2296 for MARCXML/MarcXchange.
2301 <varlistentry><term><literal>outputformat</literal> (REQUIRED)</term>
2304 Format of output. Supported values are
2305 <literal>line</literal> (MARC line format);
2306 <literal>marcxml</literal> (for MARCXML),
2307 <literal>marc</literal> (ISO2709),
2308 <literal>marcxhcange</literal> (for MarcXchange).
2313 <varlistentry><term><literal>inputcharset</literal> (OPTIONAL)</term>
2316 Encoding of input. For XML input formats, this need not
2317 be given, but for ISO2709 based inputformats, this should
2318 be set to the encoding used. For MARC21 records, a common
2319 inputcharset value would be <literal>marc-8</literal>.
2324 <varlistentry><term><literal>outputcharset</literal> (OPTIONAL)</term>
2327 Encoding of output. If outputformat is XML based, it is
2328 strongly recommened to use <literal>utf-8</literal>.
2337 <varlistentry><term><literal>xslt</literal></term>
2340 The <literal>xslt</literal> element specifies a conversion
2341 via &acro.xslt;. The following attributes may be specified:
2344 <varlistentry><term><literal>stylesheet</literal> (REQUIRED)</term>
2359 <sect2 id="tools.retrieval.examples">
2360 <title>Retrieval Facility Examples</title>
2361 <example id="tools.retrieval.marc21">
2362 <title>MARC21 backend</title>
2364 A typical way to use the retrieval facility is to enable XML
2365 for servers that only supports ISO2709 encoded MARC21 records.
2367 <programlisting><![CDATA[
2369 <retrieval syntax="usmarc" name="F"/>
2370 <retrieval syntax="usmarc" name="B"/>
2371 <retrieval syntax="xml" name="marcxml"
2372 identifier="info:srw/schema/1/marcxml-v1.1">
2373 <backend syntax="usmarc" name="F">
2374 <marc inputformat="marc" outputformat="marcxml"
2375 inputcharset="marc-8"/>
2378 <retrieval syntax="xml" name="dc">
2379 <backend syntax="usmarc" name="F">
2380 <marc inputformat="marc" outputformat="marcxml"
2381 inputcharset="marc-8"/>
2382 <xslt stylesheet="MARC21slim2DC.xsl"/>
2389 This means that our frontend supports:
2393 MARC21 F(ull) records.
2398 MARC21 B(rief) records.
2410 Dublin core records.
2417 <sect2 id="tools.retrieval.api">
2420 It should be easy to use the retrieval systems from applications. Refer
2422 <filename>yaz/retrieval.h</filename> and
2423 <filename>yaz/record_conv.h</filename>.
2429 <!-- Keep this comment at the end of the file
2434 sgml-minimize-attributes:nil
2435 sgml-always-quote-attributes:t
2438 sgml-parent-document: "yaz.xml"
2439 sgml-local-catalogs: nil
2440 sgml-namecase-general:t