-<!-- $Id: zoom.xml,v 1.12 2001-11-18 21:14:22 adam Exp $ -->
+<!-- $Id: zoom.xml,v 1.21 2002-12-09 23:32:29 adam Exp $ -->
<chapter id="zoom"><title>Building clients with 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
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>
- ZOOM_connection ZOOM_connection_new (const char *host, int portnum);
+ ZOOM_connection ZOOM_connection_new (const char *host, int portnum);
- ZOOM_connection ZOOM_connection_create (ZOOM_options options);
-
- void ZOOM_connection_connect(ZOOM_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 ZOOM_connection_destroy (ZOOM_connection c);
+ void ZOOM_connection_destroy (ZOOM_connection c);
</synopsis>
<para>
Connection objects are created with either function
a connection immediately, thus allowing you to specify options
before establishing network connection using the function
<function>ZOOM_connection_connect</function>.
- If the portnumber, <literal>portnum</literal>, is zero, the
+ 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
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>ZOOM_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="sides" colsep="1"><title>ZOOM Connection Options</title>
+ <table frame="top"><title>ZOOM Connection Options</title>
<tgroup cols="3">
<colspec colwidth="4*" colname="name"></colspec>
<colspec colwidth="7*" colname="description"></colspec>
</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.
<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>
+ targetImplementationId</entry><entry> Implementation ID of target.
+ </entry><entry>none</entry></row>
+ <row><entry>
+ targetImplementationName</entry><entry> Implementation Name of target.
+ </entry><entry>none</entry></row>
+ <row><entry>
+ targetImplementationVersion</entry><entry> Implementation Version
+ of target.
+ </entry><entry>none</entry></row>
</tbody>
</tgroup>
</table>
+ <para>
+ 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 ZOOM_connection_error (ZOOM_connection c, const char **cp,
- const char **addinfo);
+ const char **addinfo);
+ int ZOOM_connection_error_x (ZOOM_connection c, const char **cp,
+ const char **addinfo, const char **dset);
</synopsis>
<para>
- Use <function>ZOOM_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>
<para>
The calls <function>ZOOM_connection_new</function> and
- <function>ZOOM_connection_connect</function> establises a TCP/IP
+ <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).
<literal>USMARC</literal>, <literal>SUTRS</literal>, etc.
</entry><entry>none</entry></row>
<row><entry>
+ schema</entry><entry>Schema for retrieval, such as
+ <literal>Gils-schema</literal>, <literal>Geo-schema</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
+ 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 greator than small set upper bound.
+ is greater than small set upper bound.
</entry><entry>0</entry></row>
<row><entry>
smallSetElementSetName</entry><entry>
databaseName</entry><entry>One or more database names
separated by character plus (<literal>+</literal>).
</entry><entry>Default</entry></row>
+ <row><entry>
+ 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>
<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
+ would be unsorted. Hence, piggyback is disabled when sort criteria
is set. Following Search - and a Possible sort, Retrieval takes
place - as one or more Present Requests - Present Response being
transferred.
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
</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>
size_t start, size_t count);
ZOOM_record ZOOM_resultset_record (ZOOM_resultset s, size_t pos);
- void *ZOOM_record_get (ZOOM_record rec, const char *type,
- size_t *len);
+ const char *ZOOM_record_get (ZOOM_record rec, const char *type,
+ size_t *len);
ZOOM_record ZOOM_record_clone (ZOOM_record rec);
<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><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>.
+ as a C null-terminated string. Return type is
+ <literal>const char *</literal>.
</para></listitem>
</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><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>
</variablelist>
</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>
+ <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);
+
+
+ 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 and start term given.
+ 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 an actual term 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.
+ 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 change behavior.
<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 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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