This extension offers a PHP interface to the YAZ toolkit that implements the Z39.50 Protocol for
Information Retrieval. With this extension you can easily implement a Z39.50 origin (client) that searches or scans Z39.50 targets (servers) in parallel.
The module hides most of the complexity of Z39.50 so it should be fairly easy to use. It supports persistent stateless connections very similar to those offered by the various RDB APIs that are
available for PHP. This means that sessions are stateless but shared among users, thus saving the connect and initialize phase steps in most cases.
YAZ is available at http://www.indexdata.dk/yaz/. You can find news information, example scripts, etc. for
this extension at http://www.indexdata.dk/phpyaz/.
Note: This extension has been removed as of PHP 5 and moved to the PECL repository.
Compile YAZ (ANSI/NISO Z39.50 support) and install it. Build PHP with your favourite modules and add option --with-yaz[=DIR]. Your task is roughly the following:
Example 1. YAZ compilation
gunzip -c php-4.3.X.tar.gz|tar xf -
gunzip -c yaz-2.0.tar.gz|tar xf -
cd yaz-2.0
./configure --prefix=/usr
make
make install
cd ../php-4.3.X.
./configure --with-yaz=/usr/bin
make
make install
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If you are using YAZ as a shared extension, add (or uncomment) the following line in php.ini on Unix:
And for Windows:
On Windows, php_yaz.dll depend on yaz.dll. You'll find yaz.dll in sub directory dlls in the
Win32 zip archive. Copy yaz.dll to a directory in your PATH environment (c:\winnt\system32 or c:\windows\system32).
| Warning |
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The IMAP extension cannot be used in conjuction with the recode, YAZ or Cyrus
extensions. This is due to the fact that they both share the same internal symbol.
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Note: The above problem is solved in version 2.0 of YAZ.
The behaviour of these functions is affected by settings in php.ini.
Table 1. YAZ configuration options
| Name |
Default |
Changeable |
| yaz.max_links |
"100" |
PHP_INI_ALL |
| yaz.log_file |
"" |
PHP_INI_ALL |
For further details and definition of the PHP_INI_* constants see
ini_set().
This extension has no resource types defined.
This extension has no constants defined.
PHP/YAZ keeps track of connections with targets (Z-Associations). A resource represents a connection to a target.
The script below demonstrates the parallel searching feature of the API. When invoked with no arguments it prints a query form; else (arguments are supplied) it searches the targets as given in
array host.
Example 2. Parallel searching using Yaz
<?php
$num_hosts = count($host);
if (empty($term) || count($host) == 0) {
echo '<form method="get">
<input type="checkbox"
name="host[]" value="bagel.indexdata.dk/gils" />
GILS test
<input type="checkbox"
name="host[]" value="localhost:9999/Default" />
local test
<input type="checkbox" checked="checked"
name="host[]" value="z3950.loc.gov:7090/voyager" />
Library of Congress
<br />
RPN Query:
<input type="text" size="30" name="term" />
<input type="submit" name="action" value="Search" />
</form>
';
} else {
echo 'You searched for ' . htmlspecialchars($term) . '<br />';
for ($i = 0; $i <
$num_hosts; $i++) {
$id[] = yaz_connect($host[$i]);
yaz_range($id[$i], 1, 10);
yaz_search($id[$i], "rpn", $term);
}
yaz_wait();
for ($i = 0; $i <
$num_hosts; $i++) {
echo '<hr />' . $host[$i] . ':';
$error = yaz_error($id[$i]);
if (!empty($error)) {
echo "Error: $error";
} else {
$hits = yaz_hits($id[$i]);
echo "Result Count $hits";
}
echo '<dl>';
for ($p = 1; $p
<= 10; $p++) {
$rec = yaz_record($id[$i], $p, "string");
if (empty($rec)) continue;
echo "<dt><b>$p</b></dt><dd>";
echo nl2br($rec);
echo "</dd>";
}
echo '</dl>';
}
}
?> |
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