YAZ Functions

简介

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: 本扩展已被移动到 » PECL 库中且自以下版本起不再被绑定到 PHP 中:5.0.0.

安装

Obtain YAZ (ANSI/NISO Z39.50 support) and install it. YAZ can be fetched in source or in various prebuilt packages from the » YAZ archive. Systems such as Debian GNU/Linux, Suse Linux, FreeBSD also has YAZ as part of their distribution.

For the PHP 4 series, the YAZ extension is bundled (but not YAZ itself) Build PHP with your favorite modules and add option --with-yaz[=DIR].

Example#1 YAZ compilation for PHP 4 on Unix


gunzip -c php-4.4.X.tar.gz|tar xf -

gunzip -c yaz-2.1.8.tar.gz|tar xf -

cd yaz-2.1.8

./configure --prefix=/usr

make

sudo make install

cd ../php-4.4.X.

./configure --with-yaz=/usr/bin

make

sudo make install

For PHP 5, the YAZ extension is in » PECL and is installed as a shared object/dll. If you have pear installed the easiest way to download, configure and install the YAZ extension is by using the pecl command.

Installation of YAZ on Linux

安装此 PECL 扩展库的信息可在手册中标题为 PECL 扩展库安装的一章中找到。 更多信息如新版本,下载,源文件,维护者信息以及更新日志等可以在这里找到: » http://pecl.php.net/package/yaz

Installation on Windows systems

可以从 » PHP 下载页面或者 » http://snaps.php.net/ 下载此 PECL 扩展的 DLL 文件。 php_yaz.dll depends on yaz.dll. The yaz.dll is part of the Win32 ZIP from the PHP site. It is also part of the Windows YAZ install available from the » YAZ WIN32 area.

Warning

The PHP 5.0.5 Win32 zip includes a too old version of yaz.dll (version 1.9.1 < required version 2.0.13). If that's the case use the yaz.dll from a newer » YAZ WIN32 install.

On windows, don't forget to add the PHP directory to the PATH, so that the yaz.dll file can be found by the system.

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


   extension=yaz.so

  
And for Windows:

   extension=php_yaz.dll

  

Warning

IMAPrecodeYAZCyrus 扩展模块不能同时使用,因为它们共享了相同的内部符号。

Note: The above problem is solved in version 2.0 of YAZ.

运行时配置

这些函数的行为受 php.ini 的影响。

YAZ configuration options
Name Default Changeable Changelog
yaz.max_links "100" PHP_INI_ALL Available since PHP 4.3.0. Removed in PHP 5.0.0.
yaz.log_file NULL PHP_INI_ALL Available since PHP 4.3.0. Removed in PHP 5.0.0.
有关 PHP_INI_* 常量进一步的细节与定义参见php.ini 配置选项

资源类型

本扩展模块未定义任何资源类型。

预定义常量

本扩展模块未定义任何常量。

范例

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
$host
=$_REQUEST[host];
$query=$_REQUEST[query];
$num_hosts count($host);
if (empty(
$query) || count($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="query" />
    <input type="submit" name="action" value="Search" />
    </form>
    '
;        
} else {
    echo 
'You searched for ' htmlspecialchars($query) . '<br />';
    for (
$i 0$i $num_hosts$i++) {
        
$id[] = yaz_connect($host[$i]);
        
yaz_syntax($id[$i], "usmarc");
        
yaz_range($id[$i], 110);
        
yaz_search($id[$i], "rpn"$query);
    }
    
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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