Introduction
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 SQL APIs that are available
for PHP. This means that sessions are stateless but shared amongst
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/.
Installation
Compile YAZ and install it. Build PHP with your favourite
modules and add option
--with-yaz.
Your task is roughly the following:
Runtime Configuration
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().
Resource Types
This extension has no resource types defined.
Predefined Constants
This extension has no constants defined.
Examples
PHP/YAZ keeps track of connections with targets
(Z-Associations). A positive integer represents the ID of a
particular association.
Example 1. Parallel searching using YAZ()
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 in array
host.
$num_hosts = count ($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="1"
name="host[]" value="z3950.bell-labs.com/books">
BELL Labs Library
<br>
RPN Query:
<input type="text" size="30" name="term">
<input type="submit" name="action" value="Search">
';
} else {
echo 'You searced for ' . htmlspecialchars($term) . '<br>';
for ($i = 0; $i < $num_hosts; $i++) {
$id[] = yaz_connect($host[$i]);
yaz_syntax($id[$i],"sutrs");
yaz_search($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 ereg_replace("\n", "<br>\n",$rec);
echo "</dd>";
}
echo '</dl>';
}
} |
|