-<!-- $Id: zoom.xml,v 1.10 2001-11-15 21:58:50 adam Exp $ -->
- <chapter id="zoom"><title>Building clients with ZOOM</title>
-
+<!-- $Id: zoom.xml,v 1.36 2003-11-25 09:55:20 mike Exp $ -->
+ <chapter id="zoom"><title>ZOOM</title>
<para>
&zoom; is an acronym for 'Z39.50 Object-Orientation Model' and is
an initiative started by Mike Taylor (Mike is from the UK, which
provide a common Z39.50 client API not bound to a particular
programming language or toolkit.
</para>
+
+ <note>
+ <para>
+ A recent addition to &yaz; is SRW support. You can now make
+ SRW ZOOM connections by specifying scheme <literal>http://</literal>
+ for the hostname for a connection.
+ </para>
+ </note>
+
<para>
The lack of a simple Z39.50 client API for &yaz; has become more
and more apparent over time. So when the first &zoom; specification
became available,
an implementation for &yaz; was quickly developed. For the first time, it is
now as easy (or easier!) to develop clients than servers with &yaz;. This
- chapter describes the &zoom; C binding. Before going futher, please
+ chapter describes the &zoom; C binding. Before going further, please
reconsider whether C is the right programming language for the job.
There are other language bindings available for &yaz;, and still
more
are in active development. See the
- <ulink url="http://zoom.z3950.org/">ZOOM website</ulink> for
+ <ulink url="http://zoom.z3950.org/">ZOOM web-site</ulink> for
more information.
</para>
-
+
<para>
In order to fully understand this chapter you should read and
try the example programs <literal>zoomtst1.c</literal>,
<literal>zoomtst2.c</literal>, .. in the <literal>zoom</literal>
directory.
</para>
-
+
<para>
- The C language misses many features found in object oriented languages
+ The C language misses features found in object oriented languages
such as C++, Java, etc. For example, you'll have to manually,
destroy all objects you create, even though you may think of them as
temporary. Most objects has a <literal>_create</literal> - and a
</para>
<para>
In each of the sections below you'll find a sub section called
- protocol behavior, that descries how the API maps to the Z39.50
+ protocol behavior, that describes how the API maps to the Z39.50
protocol.
</para>
<sect1 id="zoom.connections"><title>Connections</title>
<para>The Connection object is a session with a target.
</para>
<synopsis>
- #include <yaz/zoom.h>
+ #include <yaz/zoom.h>
- Z3950_connection Z3950_connection_new (const char *host, int portnum);
+ ZOOM_connection ZOOM_connection_new (const char *host, int portnum);
- Z3950_connection Z3950_connection_create (Z3950_options options);
-
- void Z3950_connection_connect(Z3950_connection c, const char *host,
+ ZOOM_connection ZOOM_connection_create (ZOOM_options options);
+
+ void ZOOM_connection_connect(ZOOM_connection c, const char *host,
int portnum);
- void Z3950_connection_destroy (Z3950_connection c);
+ void ZOOM_connection_destroy (ZOOM_connection c);
</synopsis>
<para>
Connection objects are created with either function
- <function>Z3950_connection_new</function> or
- <function>Z3950_connection_create</function>.
+ <function>ZOOM_connection_new</function> or
+ <function>ZOOM_connection_create</function>.
The former creates and automatically attempts to establish a network
connection with the target. The latter doesn't establish
a connection immediately, thus allowing you to specify options
before establishing network connection using the function
- <function>Z3950_connection_connect</function>.
- If the portnumber, <literal>portnum</literal>, is zero, the
+ <function>ZOOM_connection_connect</function>.
+ If the port number, <literal>portnum</literal>, is zero, the
<literal>host</literal> is consulted for a port specification.
If no port is given, 210 is used. A colon denotes the beginning of
a port number in the host string. If the host string includes a
slash, the following part specifies a database for the connection.
</para>
<para>
+ You can prefix the host with a scheme followed by colon. The
+ default scheme is <literal>tcp</literal> (Z39.50 protocol).
+ The scheme <literal>http</literal> selects SRW over HTTP.
+ </para>
+ <para>
Connection objects should be destroyed using the function
- <function>Z3950_connection_destroy</function>.
+ <function>ZOOM_connection_destroy</function>.
</para>
<synopsis>
- void Z3950_connection_option_set (Z3950_connection c,
- const char *key,
- const char *val);
-
- const char *Z3950_connection_option_get (Z3950_connection c,
- const char *key);
+ void ZOOM_connection_option_set (ZOOM_connection c,
+ const char *key,
+ const char *val);
- const char *Z3950_connection_host (Z3950_connection c);
+ const char *ZOOM_connection_option_get (ZOOM_connection c,
+ const char *key);
</synopsis>
<para>
- The <function>Z3950_connection_option_set</function> allows you to
+ The <function>ZOOM_connection_option_set</function> allows you to
set an option given by <parameter>key</parameter> to the value
<parameter>value</parameter> for the connection.
- Function <function>Z3950_connection_option_get</function> returns
+ Function <function>ZOOM_connection_option_get</function> returns
the value for an option given by <parameter>key</parameter>.
</para>
<table frame="top"><title>ZOOM Connection Options</title>
</entry><entry>none</entry></row>
<row><entry>
pass</entry><entry>Authentication password
- </entry><entry>none</entry></row>
+ </entry><entry>none</entry></row>
+ <row><entry>
+ host</entry><entry>Target host. This setting is "read-only".
+ It's automatically set internally when connecting to a target.
+ </entry><entry>none</entry></row>
<row><entry>
proxy</entry><entry>Proxy host
</entry><entry>none</entry></row>
async</entry><entry>If true (1) the connection operates in
asynchronous operation which means that all calls are non-blocking
except
- <link linkend="zoom.events"><function>Z3950_event</function></link>.
+ <link linkend="zoom.events"><function>ZOOM_event</function></link>.
</entry><entry>0</entry></row>
<row><entry>
maximumRecordSize</entry><entry> Maximum size of single record.
<row><entry>
preferredMessageSize</entry><entry> Maximum size of multiple records.
</entry><entry>1 MB</entry></row>
+ <row><entry>
+ lang</entry><entry> Language for negotiation.
+ </entry><entry>none</entry></row>
+ <row><entry>
+ charset</entry><entry> Character set for negotiation.
+ </entry><entry>none</entry></row>
+ <row><entry>
+ serverImplementationId</entry><entry>
+ Implementation ID of server. (The old targetImplementationId
+ option is also supported for the benefit of old applications.)
+ </entry><entry>none</entry></row>
+ <row><entry>
+ targetImplementationName</entry><entry>
+ Implementation Name of server. (The old
+ targetImplementationName option is also supported for the
+ benefit of old applications.)
+ </entry><entry>none</entry></row>
+ <row><entry>
+ serverImplementationVersion</entry><entry>
+ Implementation Version of server. (the old
+ targetImplementationVersion option is also supported for the
+ benefit of old applications.)
+ </entry><entry>none</entry></row>
+ <row><entry>
+ databaseName</entry><entry>One or more database names
+ separated by character plus (<literal>+</literal>), which to
+ be used by subsequent search requests on this Connection.
+ </entry><entry>Default</entry></row>
+ <row><entry>
+ piggyback</entry><entry>True (1) if piggyback should be
+ used in searches; false (0) if not.
+ </entry><entry>1</entry></row>
+ <row><entry>
+ smallSetUpperBound</entry><entry>If hits is less than or equal to this
+ value, then target will return all records using small element set name
+ </entry><entry>0</entry></row>
+ <row><entry>
+ largeSetLowerBound</entry><entry>If hits is greater than this
+ value, the target will return no records.
+ </entry><entry>1</entry></row>
+ <row><entry>
+ mediumSetPresentNumber</entry><entry>This value represents
+ the number of records to be returned as part of a search when when
+ hits is less than or equal to large set lower bound and if hits
+ is greater than small set upper bound.
+ </entry><entry>0</entry></row>
+ <row><entry>
+ smallSetElementSetName</entry><entry>
+ The element set name to be used for small result sets.
+ </entry><entry>none</entry></row>
+ <row><entry>
+ mediumSetElementSetName</entry><entry>
+ The element set name to be for medium-sized result sets.
+ </entry><entry>none</entry></row>
</tbody>
</tgroup>
</table>
<para>
- Function <function>Z3950_connection_host</function> returns
- the host for the connection as specified in a call to
- <function>Z3950_connection_new</function> or
- <function>Z3950_connection_connect</function>.
- This function returns <literal>NULL</literal> if host isn't
- set for the connection.
+ If either option <literal>lang</literal> or <literal>charset</literal>
+ is set, then
+ <ulink url="http://lcweb.loc.gov/z3950/agency/defns/charneg-3.html">
+ Character Set and Language Negotiation</ulink> is in effect.
</para>
<synopsis>
- int Z3950_connection_error (Z3950_connection c, const char **cp,
- const char **addinfo);
+ int ZOOM_connection_error (ZOOM_connection c, const char **cp,
+ const char **addinfo);
+ int ZOOM_connection_error_x (ZOOM_connection c, const char **cp,
+ const char **addinfo, const char **dset);
</synopsis>
<para>
- Use <function>Z3950_connection_error</function> to check for
+ Function <function>ZOOM_connection_error</function> checks for
errors for the last operation(s) performed. The function returns
zero if no errors occurred; non-zero otherwise indicating the error.
Pointers <parameter>cp</parameter> and <parameter>addinfo</parameter>
holds messages for the error and additional-info if passed as
- non-<literal>NULL</literal>.
+ non-<literal>NULL</literal>. Function
+ <function>ZOOM_connection_error_x</function> is an extended version
+ of <function>ZOOM_connection_error</function> that is capable of
+ returning name of diagnostic set in <parameter>dset</parameter>.
</para>
- <sect2><title>Protocol behavior</title>
+ <sect2><title>Z39.50 Protocol behavior</title>
<para>
- The calls <function>Z3950_connection_new</function> and
- <function>Z3950_connection_connect</function> establises a TCP/IP
+ The calls <function>ZOOM_connection_new</function> and
+ <function>ZOOM_connection_connect</function> establishes a TCP/IP
connection and sends an Initialize Request to the target if
possible. In addition, the calls waits for an Initialize Response
from the target and the result is inspected (OK or rejected).
<para>
When option <literal>async</literal> is 1, it really means that
all network operations are postponed (and queued) until the
- function <literal>Z3950_event</literal> is invoked. When doing so
+ function <literal>ZOOM_event</literal> is invoked. When doing so
it doesn't make sense to check for errors after
- <literal>Z3950_connection_new</literal> is called since that
+ <literal>ZOOM_connection_new</literal> is called since that
operation "connecting - and init" is still incomplete and the
API cannot tell the outcome (yet).
</para>
</sect2>
+ <sect2><title>SRW Protocol behavior</title>
+ <para>
+ The SRW protocol doesn't feature an Inititialize Request, so
+ the connection phase merely establishes a TCP/IP connection
+ with the SOAP service.
+ </para>
+ <para>Most of the ZOOM connection options do not
+ affect SRW and they are ignored. However, future versions
+ of &yaz; might honor <literal>implementationName</literal> and
+ put that as part of User-Agent header for HTTP requests.
+ </para>
+ <para>
+ The <literal>charset</literal> is used in the Content-Type header
+ of HTTP requests.
+ </para>
+ </sect2>
</sect1>
<sect1 id="zoom.query"><title>Queries</title>
<para>
Query objects represents queries.
</para>
<synopsis>
- Z3950_query Z3950_query_create(void);
+ ZOOM_query ZOOM_query_create(void);
+
+ void ZOOM_query_destroy(ZOOM_query q);
- void Z3950_query_destroy(Z3950_query q);
+ int ZOOM_query_prefix(ZOOM_query q, const char *str);
- int Z3950_query_prefix(Z3950_query q, const char *str);
+ int ZOOM_query_cql(ZOOM_query s, const char *str);
- int Z3950_query_sortby(Z3950_query q, const char *criteria);
+ int ZOOM_query_sortby(ZOOM_query q, const char *criteria);
</synopsis>
<para>
- Create query objects using <function>Z3950_query_create</function>
- and destroy them by calling <function>Z3950_query_destroy</function>.
+ Create query objects using <function>ZOOM_query_create</function>
+ and destroy them by calling <function>ZOOM_query_destroy</function>.
RPN-queries can be specified in <link linkend="PQF">PQF</link>
notation by using the
- function <function>Z3950_query_prefix</function>. More
- query types will be added later, such as
+ function <function>ZOOM_query_prefix</function>.
+ The <function>ZOOM_query_cql</function> specifies a CQL
+ query to be sent to the server/target.
+ More query types will be added in future versions of &yaz;, such as
<link linkend="CCL">CCL</link> to RPN-mapping, native CCL query,
etc. In addition to a search, a sort criteria may be set. Function
- <function>Z3950_query_sortby</function> specifies a
+ <function>ZOOM_query_sortby</function> specifies a
sort criteria using the same string notation for sort as offered by
the <link linkend="sortspec">YAZ client</link>.
</para>
a target.
</para>
<synopsis>
- Z3950_resultset Z3950_connection_search(Z3950_connection,
- Z3950_query q);
+ ZOOM_resultset ZOOM_connection_search(ZOOM_connection,
+ ZOOM_query q);
- Z3950_resultset Z3950_connection_search_pqf(Z3950_connection c,
- const char *q);
+ ZOOM_resultset ZOOM_connection_search_pqf(ZOOM_connection c,
+ const char *q);
- void Z3950_resultset_destroy(Z3950_resultset r);
+ void ZOOM_resultset_destroy(ZOOM_resultset r);
</synopsis>
<para>
- Function <function>Z3950_connection_search</function> creates
+ Function <function>ZOOM_connection_search</function> creates
a result set given a connection and query.
Destroy a result set by calling
- <function>Z3950_resultset_destroy</function>.
+ <function>ZOOM_resultset_destroy</function>.
Simple clients may using PQF only may use function
- <function>Z3950_connection_search_pqf</function> in which case
+ <function>ZOOM_connection_search_pqf</function> in which case
creating query objects is not necessary.
</para>
<synopsis>
- void Z3950_resultset_option_set (Z3950_resultset r,
+ void ZOOM_resultset_option_set (ZOOM_resultset r,
const char *key,
const char *val);
- const char *Z3950_resultset_option_get (Z3950_resultset r,
+ const char *ZOOM_resultset_option_get (ZOOM_resultset r,
const char *key);
- size_t Z3950_resultset_size (Z3950_resultset r);
+ size_t ZOOM_resultset_size (ZOOM_resultset r);
</synopsis>
<para>
- Functions <function>Z3950_resultset_options_set</function> and
- <function>Z3950_resultset_get</function> sets and gets an option
- for a result set similar to <function>Z3950_connection_option_get</function>
- and <function>Z3950_connection_option_set</function>.
+ Functions <function>ZOOM_resultset_options_set</function> and
+ <function>ZOOM_resultset_get</function> sets and gets an option
+ for a result set similar to <function>ZOOM_connection_option_get</function>
+ and <function>ZOOM_connection_option_set</function>.
</para>
<para>
The number of hits also called result-count is returned by
- function <function>Z3950_resultset_size</function>.
+ function <function>ZOOM_resultset_size</function>.
</para>
<table frame="top"><title>ZOOM Result set Options</title>
<tgroup cols="3">
</thead>
<tbody>
<row><entry>
- piggyback</entry><entry>True (1) if piggyback should be
- used in searches; false (0) if not.
- </entry><entry>1</entry></row>
- <row><entry>
start</entry><entry>Offset of first record to be
retrieved from target. First record has offset 0 unlike the
protocol specifications where first record has position 1.
count</entry><entry>Number of records to be retrieved.
</entry><entry>0</entry></row>
<row><entry>
+ presentChunk</entry><entry>The number of records to be
+ requested from the server in each chunk (present requst). The
+ value 0 means to request all the records in a single chunk.
+ (The old <literal>step</literal>
+ option is also supported for the benefit of old applications.)
+ </entry><entry>0</entry></row>
+ <row><entry>
elementSetName</entry><entry>Element-Set name of records.
Most targets should honor element set name <literal>B</literal>
and <literal>F</literal> for brief and full respectively.
<literal>USMARC</literal>, <literal>SUTRS</literal>, etc.
</entry><entry>none</entry></row>
<row><entry>
- smallSetUpperBound</entry><entry>If hits is less than or equal to this
- value, then target will return all records using small element set name
- </entry><entry>0</entry></row>
- <row><entry>
- largeSetLowerBound</entry><entry>If hits is greator than this
- value, the target will return no records.
- </entry><entry>1</entry></row>
- <row><entry>
- mediumSetPresentNumber</entry><entry>This value represents
- the number of records to be returned as part of a search when when
- hits is less than or equal to large set lower bound and if hits
- is greator than small set upper bound.
- </entry><entry>0</entry></row>
- <row><entry>
- smallSetElementSetName</entry><entry>
- The element set name to be used for small result sets.
- </entry><entry>none</entry></row>
- <row><entry>
- mediumSetElementSetName</entry><entry>
- The element set name to be for medium-sized result sets.
+ schema</entry><entry>Schema for retrieval, such as
+ <literal>Gils-schema</literal>, <literal>Geo-schema</literal>, etc.
</entry><entry>none</entry></row>
<row><entry>
- databaseName</entry><entry>One or more database names
- separated by character plus (<literal>+</literal>).
- </entry><entry>Default</entry></row>
+ setname</entry><entry>Name of Result Set (Result Set ID).
+ If this option isn't set, the ZOOM module will automatically
+ allocate a result set name.
+ </entry><entry>default</entry></row>
</tbody>
</tgroup>
</table>
<sect2>
- <title>Protocol behavior</title>
+ <title>Z39.50 Protocol behavior</title>
<para>
The creation of a result set involves at least a SearchRequest
- SearchResponse protocol handshake. Following that, if a sort
- critieria was specified as part of the query, a sortRequest -
+ criteria was specified as part of the query, a SortRequest -
SortResponse handshake takes place. Note that it is necessary to
perform sorting before any retrieval takes place, so no records will
be returned from the target as part of the SearchResponse because these
- would be unsorted. Hence, piggyback is disabled when sort critieria
- is set. Following Search - and a Possible sort, Retrieval takes
- place - as one or more Present Requests - Present Response being
+ would be unsorted. Hence, piggyback is disabled when sort criteria
+ are set. Following Search - and a possible sort - Retrieval takes
+ place - as one or more Present Requests/Response pairs being
transferred.
</para>
<para>
The API allows for two different modes for retrieval. A high level
mode which is somewhat more powerful and a low level one.
- The low level is "enabled" when the settings
+ The low level is enabled when searching on a Connection object
+ for which the settings
<literal>smallSetUpperBound</literal>,
<literal>mediumSetPresentNumber</literal> and
<literal>largeSetLowerBound</literal> are set. The low level mode
because of a record size limit, etc. the client will repeat sending
present requests. As an example, if option <literal>start</literal>
is 0 (default) and <literal>count</literal> is 4, and
- <literal>piggyback</literal> is 1 (default) and no sorting critieria
+ <literal>piggyback</literal> is 1 (default) and no sorting criteria
is specified, then the client will attempt to retrieve the 4
records as part the search response (using piggyback). On the other
hand, if either <literal>start</literal> is positive or if
to specify one elementSetName option rather than three.
</para>
</sect2>
+ <sect2>
+ <title>SRW Protocol behavior</title>
+ <para>
+ Current version of &yaz; does not take advantage of a result set id
+ returned by the SRW server. Future versions might do, however.
+ Since, the ZOOM driver does not save result set IDs any
+ present (retrieval) is transformed to a SRW SearchRetrieveRequest
+ with same query but, possibly, different offsets.
+ </para>
+ <para>
+ Option <literal>schema</literal> specifies SRW schema
+ for retrieval. However, options <literal>elementSetName</literal> and
+ <literal>preferredRecordSyntax</literal> are ignored.
+ </para>
+ <para>
+ Options <literal>start</literal> and <literal>count</literal>
+ are supported by SRW.
+ The remaining options
+ <literal>piggyback</literal>,
+ <literal>smallSetUpperBound</literal>,
+ <literal>largeSetLowerBound</literal>,
+ <literal>mediumSetPresentNumber</literal>,
+ <literal>mediumSetElementSetName</literal>,
+ <literal>smallSetElementSetName</literal> are
+ unsupported.
+ </para>
+ <para>
+ SRW supports CQL queries, <emphasis>not</emphasis> PQF.
+ If PQF is used, however, the PQF query is transferred anyway
+ using non-standard element <literal>pQuery</literal> in
+ SRW SearchRetrieveRequest.
+ </para>
+ <para>
+ Unfortunately, SRW does not define a database setting. Hence,
+ <literal>databaseName</literal> is unsupported and ignored.
+ However, the path part in host parameter for functions
+ <function>ZOOM_connecton_new</function> and
+ <function>ZOOM_connection_connect</function> acts as a
+ database (at least for the &yaz; SRW server).
+ </para>
+ </sect2>
</sect1>
<sect1 id="zoom.records"><title>Records</title>
<para>
- A record object is a retrival record on the client side -
+ A record object is a retrieval record on the client side -
created from result sets.
</para>
<synopsis>
- void Z3950_resultset_records (Z3950_resultset r,
- Z3950_record *recs,
- size_t start, size_t count);
- Z3950_record Z3950_resultset_record (Z3950_resultset s, size_t pos);
+ void ZOOM_resultset_records (ZOOM_resultset r,
+ ZOOM_record *recs,
+ size_t start, size_t count);
+ ZOOM_record ZOOM_resultset_record (ZOOM_resultset s, size_t pos);
- void *Z3950_record_get (Z3950_record rec, const char *type,
- size_t *len);
+ const char *ZOOM_record_get (ZOOM_record rec, const char *type,
+ size_t *len);
- Z3950_record Z3950_record_dup (Z3950_record rec);
+ ZOOM_record ZOOM_record_clone (ZOOM_record rec);
- void Z3950_record_destroy (Z3950_record rec);
+ void ZOOM_record_destroy (ZOOM_record rec);
</synopsis>
<para>
References to temporary records are returned by functions
- <function>Z3950_resultset_records</function> or
- <function>Z3950_resultset_record</function>.
+ <function>ZOOM_resultset_records</function> or
+ <function>ZOOM_resultset_record</function>.
</para>
<para>
- If a persistent pointer to a record is desired
- <function>Z3950_record_dup</function> should be used.
- It returns a record reference that at any
- later stage should be destroyed by
- <function>Z3950_record_destroy</function>.
+ If a persistent reference to a record is desired
+ <function>ZOOM_record_clone</function> should be used.
+ It returns a record reference that should be destroyed
+ by a call to <function>ZOOM_record_destroy</function>.
</para>
<para>
A single record is returned by function
- <function>Z3950_resultset_record</function> that takes a
+ <function>ZOOM_resultset_record</function> that takes a
position as argument. First record has position zero.
If no record could be obtained <literal>NULL</literal> is returned.
</para>
<para>
- Function <function>Z3950_resultset_records</function> retrieves
+ Function <function>ZOOM_resultset_records</function> retrieves
a number of records from a result set. Parameter <literal>start</literal>
and <literal>count</literal> specifies the range of records to
be returned. Upon completion array
<literal>recs[0], ..recs[count-1]</literal>
holds record objects for the records. The array of records
- <literal>recs</literal> should be allocate prior to calling
- <function>Z3950_resultset_records</function>. Note that for those
+ <literal>recs</literal> should be allocated prior the call
+ <function>ZOOM_resultset_records</function>. Note that for those
records that couldn't be retrieved from the target
<literal>recs[ ..]</literal> is set to <literal>NULL</literal>.
</para>
<para id="zoom.record.get">
In order to extract information about a single record,
- <function>Z3950_record_get</function> is provided. The
+ <function>ZOOM_record_get</function> is provided. The
function returns a pointer to certain record information. The
- nature (type) of the pointer depends on the <function>type</function>
- given. In addition for certain types, the length
+ nature (type) of the pointer depends on the parameter,
+ <parameter>type</parameter>.
+ </para>
+ <para>
+ The <parameter>type</parameter> is a string of the format:
+ </para>
+ <para>
+ <replaceable>form</replaceable>[; charset=<replaceable>from</replaceable>[,<replaceable>to</replaceable>]]
+ </para>
+ <para>
+ where <replaceable>form</replaceable> specifies the format of the
+ returned record, <replaceable>from</replaceable>
+ specifies the character set of the record in its original form
+ (as returned by the server), <replaceable>to</replaceable> specifies
+ the output (returned)
+ character set encoding.
+ If charset is not given, then no character set conversion takes place.
+ If <replaceable>to</replaceable> is omitted UTF-8 is assumed.
+ </para>
+ <para>
+ In addition, for certain types, the length
<literal>len</literal> passed will be set to the size in bytes of
- the returned information.
+ the returned information.
+ </para>
+ <para>
+ The following are the supported values for <replaceable>form</replaceable>.
<variablelist>
<varlistentry><term><literal>database</literal></term>
<listitem><para>Database of record is returned
- as a C null-terminated string. Return type <literal>char *</literal>.
+ as a C null-terminated string. Return type
+ <literal>const char *</literal>.
</para></listitem>
- </varlistentry>
+ </varlistentry>
<varlistentry><term><literal>syntax</literal></term>
- <listitem><para>The transfer syntax (OID) of the record is returned
- as a C null-terminated string. Return type <literal>char *</literal>.
+ <listitem><para>The transfer syntax of the record is returned
+ as a C null-terminated string containing the symbolic name of
+ the record syntax, e.g. <literal>Usmarc</literal>. Return type
+ is
+ <literal>const char *</literal>.
</para></listitem>
- </varlistentry>
+ </varlistentry>
<varlistentry><term><literal>render</literal></term>
<listitem><para>The record is returned in a display friendly
format. Upon completion buffer is returned
- (type <literal>char *</literal>) and length is stored in
+ (type <literal>const char *</literal>) and length is stored in
<literal>*len</literal>.
</para></listitem>
- </varlistentry>
+ </varlistentry>
<varlistentry><term><literal>raw</literal></term>
<listitem><para>The record is returned in the internal
- YAZ specific format. The raw data is returned as type
+ YAZ specific format. For GRS-1, Explain, and others, the
+ raw data is returned as type
<literal>Z_External *</literal> which is just the type for
the member <literal>retrievalRecord</literal> in
type <literal>NamePlusRecord</literal>.
+ For SUTRS and octet aligned record (including all MARCs) the
+ octet buffer is returned and the length of the buffer.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry><term><literal>xml</literal></term>
+ <listitem><para>The record is returned in XML if possible.
+ SRW/SRU and Z39.50 records with transfer syntax XML are
+ returned verbatim. MARC records are returned in
+ <ulink url="http://www.loc.gov/standards/marcxml/">
+ MARCXML
+ </ulink>
+ (converted from ISO2709 to MARCXML by YAZ).
+ GRS-1 and OPAC records are not supported for this form.
+ Upon completion, the XML buffer is returned
+ (type <literal>const char *</literal>) and length is stored in
+ <literal>*len</literal>.
</para></listitem>
- </varlistentry>
+ </varlistentry>
+ <varlistentry><term><literal>opac</literal></term>
+ <listitem><para>OPAC for record is returned in XML.
+ </para></listitem>
+ </varlistentry>
</variablelist>
</para>
- <sect2><title>Protocol behavior</title>
+ <para>
+ Most
+ <ulink url="http://www.loc.gov/marc/">
+ MARC21
+ </ulink>
+ records uses the
+ <ulink url="http://www.loc.gov/marc/specifications/speccharmarc8.html">
+ MARC-8
+ </ulink>
+ character set encoding.
+ An application that wishes to display in Latin-1 would use
+ <screen>
+ render; charset=marc8,iso-8859-1
+ </screen>
+ </para>
+ <sect2><title>Z39.50 Protocol behavior</title>
+ <para>
+ The functions <function>ZOOM_resultset_record</function> and
+ <function>ZOOM_resultset_records</function> inspects the client-side
+ record cache. Records not found in cache are fetched using
+ Present.
+ The functions may block (and perform network I/O) - even though option
+ <literal>async</literal> is 1, because they return records objects.
+ (and there's no way to return records objects without retrieving them!).
+ </para>
<para>
- The functions <function>Z3950_resultset_record</function> and
- <function>Z3950_resultset_records</function> inspects the client-side
- record cache. If the records(s) were not found, i.e. not yet retrieved
- from, they are fetched using Present Requests.
+ There is a trick, however, in the usage of function
+ <function>ZOOM_resultset_records</function> that allows for
+ delayed retrieval (and makes it non-blocking). By using
+ a null pointer for <parameter>recs</parameter> you're indicating
+ you're not interested in getting records objects
+ <emphasis>now</emphasis>.
</para>
</sect2>
+ <sect2><title>SRW Protocol behavior</title>
+ <para>
+ The ZOOM driver for SRW treats records returned by a SRW server
+ as if they where Z39.50 records with transfer syntax XML and
+ no element set name or database name.
+ </para>
+ </sect2>
+ </sect1>
+ <sect1 id="zoom.scan"><title>Scan</title>
+ <para>
+ This section describes an interface for Scan. Scan is not an
+ official part of the ZOOM model yet. The result of a scan operation
+ is the <literal>ZOOM_scanset</literal> which is a set of terms
+ returned by a target.
+ </para>
+
+ <para>
+ The Scan interface is Z39.50 only. SRW version 1.0 does not
+ support this.
+ </para>
+
+ <synopsis>
+ ZOOM_scanset ZOOM_connection_scan (ZOOM_connection c,
+ const char *startterm);
+
+ size_t ZOOM_scanset_size(ZOOM_scanset scan);
+
+ const char * ZOOM_scanset_term(ZOOM_scanset scan, size_t pos,
+ int *occ, size_t *len);
+
+ const char * ZOOM_scanset_display_term(ZOOM_scanset scan, size_t pos,
+ int *occ, size_t *len);
+
+ void ZOOM_scanset_destroy (ZOOM_scanset scan);
+
+ const char *ZOOM_scanset_option_get (ZOOM_scanset scan,
+ const char *key);
+
+ void ZOOM_scanset_option_set (ZOOM_scanset scan, const char *key,
+ const char *val);
+ </synopsis>
+ <para>
+ The scan set is created by function
+ <function>ZOOM_connection_scan</function> which performs a scan
+ operation on the connection using the specified startterm.
+ If the operation was successful, the size of the scan set can be
+ retrieved by a call to <function>ZOOM_scanset_size</function>.
+ Like result sets, the items are numbered 0,..size-1.
+ To obtain information about a particular scan term, call function
+ <function>ZOOM_scanset_term</function>. This function takes
+ a scan set offset <literal>pos</literal> and returns a pointer
+ to a <emphasis>raw term</emphasis> or <literal>NULL</literal> if
+ non-present.
+ If present, the <literal>occ</literal> and <literal>len</literal>
+ are set to the number of occurrences and the length
+ of the actual term respectively.
+ <function>ZOOM_scanset_display_term</function> is similar to
+ <function>ZOOM_scanset_term</function> except that it returns
+ the <emphasis>display term</emphasis> rather than the raw term.
+ In a few cases, the term is different from display term. Always
+ use the display term for display and the raw term for subsequent
+ scan operations (to get more terms, next scan result, etc).
+ </para>
+ <para>
+ A scan set may be freed by a call to function
+ <function>ZOOM_scanset_destroy</function>.
+ Functions <function>ZOOM_scanset_option_get</function> and
+ <function>ZOOM_scanset_option_set</function> retrieves and sets
+ an option respectively.
+ </para>
+
+ <table frame="top"><title>ZOOM Scan Set Options</title>
+ <tgroup cols="3">
+ <colspec colwidth="4*" colname="name"></colspec>
+ <colspec colwidth="7*" colname="description"></colspec>
+ <colspec colwidth="2*" colname="default"></colspec>
+ <thead>
+ <row>
+ <entry>Option</entry>
+ <entry>Description</entry>
+ <entry>Default</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row><entry>
+ number</entry><entry>Number of Scan Terms requested in next scan.
+ After scan it holds the actual number of terms returned.
+ </entry><entry>10</entry></row>
+ <row><entry>
+ position</entry><entry>Preferred Position of term in response
+ in next scan; actual position after completion of scan.
+ </entry><entry>1</entry></row>
+ <row><entry>
+ stepSize</entry><entry>Step Size
+ </entry><entry>0</entry></row>
+ <row><entry>
+ scanStatus</entry><entry>An integer indicating the Scan Status
+ of last scan.
+ </entry><entry>0</entry></row>
+ </tbody>
+ </tgroup>
+ </table>
+
</sect1>
<sect1 id="zoom.options"><title>Options</title>
<para>
- Most &zoom; objects provide a way to specify options to default behavior.
+ Most &zoom; objects provide a way to specify options to change behavior.
From an implementation point of view a set of options is just like
- an associate array / hash array, etc.
+ an associative array / hash array, etc.
</para>
<synopsis>
- Z3950_options Z3950_options_create (void);
+ ZOOM_options ZOOM_options_create (void);
- Z3950_options Z3950_options_create_with_parent (Z3950_options parent);
+ ZOOM_options ZOOM_options_create_with_parent (ZOOM_options parent);
- void Z3950_options_destroy (Z3950_options opt);
+ void ZOOM_options_destroy (ZOOM_options opt);
</synopsis>
<synopsis>
- const char *Z3950_options_get (Z3950_options opt, const char *name);
+ const char *ZOOM_options_get (ZOOM_options opt, const char *name);
- void Z3950_options_set (Z3950_options opt, const char *name,
- const char *v);
+ void ZOOM_options_set (ZOOM_options opt, const char *name,
+ const char *v);
</synopsis>
<synopsis>
- typedef const char *(*Z3950_options_callback)
+ typedef const char *(*ZOOM_options_callback)
(void *handle, const char *name);
- Z3950_options_callback
- Z3950_options_set_callback (Z3950_options opt,
- Z3950_options_callback c,
- void *handle);
+ ZOOM_options_callback
+ ZOOM_options_set_callback (ZOOM_options opt,
+ ZOOM_options_callback c,
+ void *handle);
</synopsis>
</sect1>
<sect1 id="zoom.events"><title>Events</title>
with events.
</para>
<synopsis>
- int Z3950_event (int no, Z3950_connection *cs);
+ int ZOOM_event (int no, ZOOM_connection *cs);
</synopsis>
<para>
- The <function>Z3950_event</function> executes pending events for
+ The <function>ZOOM_event</function> executes pending events for
a number of connections. Supply the number of connections in
<literal>no</literal> and an array of connections in
<literal>cs</literal> (<literal>cs[0] ... cs[no-1]</literal>).
A pending event could be a sending a search, receiving a response,
etc.
- When an event has a occured for one of the connections, this function
+ When an event has occurred for one of the connections, this function
returns a positive integer <literal>n</literal> denoting that an event
occurred for connection <literal>cs[n-1]</literal>.
When no events are pending for the connections, a value of zero is
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