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.
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:
If you are using YAZ as a shared extension, add (or uncomment) the following line in php.ini on Unix:
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).
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
|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.|
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