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 moved to the PECL repository and is no longer bundled with
PHP as of PHP 5.0.0.
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 |
|
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 |
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. |
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 | Changelog |
|---|
| yaz.max_links | "100" | PHP_INI_ALL | Available since PHP 4.3.0. |
| yaz.log_file | NULL | PHP_INI_ALL | Available since PHP 4.3.0. |
For further details and definitions of the
PHP_INI_* constants, see the
Appendix H.
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>';
}
}
?>
|
|
