本文实例讲述了PHP自定义函数获取搜索引擎来源关键字的方法。分享给大家供大家参考，具体如下：

获取搜索引擎来源关键字的函数：

function getKeywords() {

  // 搜索引擎关键字映射

  static $host_keyword_map = array(

      'www.baidu.com' => 'wd',

      'v.baidu.com' => 'word',

      'image.baidu.com' => 'word',

      'news.baidu.com' => 'word',

      'www.so.com' => 'q',

      'video.so.com' => 'q',

      'image.so.com' => 'q',

      'news.so.com' => 'q',

      'www.sogou.com' => 'query',

      'pic.sogou.com' => 'query',

      'v.sogou.com' => 'query',

  );

  // 检查来源是否搜索引擎

  if (!isset($_SERVER['HTTP_REFERER'])) {

    return '';

  }

  $urls = parse_url($_SERVER['HTTP_REFERER']);

  if (!array_key_exists($urls['host'], $host_keyword_map)) {

    return '';

  }

  $key = $host_keyword_map[$urls['host']];

  // 检查关键字参数是否存在

  if (!isset($urls['query'])) {

    return '';

  }

  $params = array();

  parse_str($urls['query'], $params);

  if (!isset($params[$key])) {

    return '';

  }

  $keywords = $params[$key];

  // 检查编码

  $encoding = mb_detect_encoding($keywords, 'utf-8,gbk');

  if ($encoding != 'utf-8') {

    $keywords = iconv($encoding, 'utf-8', $keywords);

  }

  return $keywords;

}

函数测试：

<?php

header("Content-Type: text/html; charset=utf-8");

$referers = array(

    'http://www.baidu.com/s?cl=3&wd=%B9%E9%C0%B4&fr=vid1000',

    'http://www.baidu.com/s?tn=92506501_hao_pg&rtt=1&bsst=1&wd=%B9%E9%C0%B4',

    'http://www.baidu.com/link?url=ctBhF7AAau6LwE61pJOEH-ZhgUM7D3YHYMrm6xIXJlDQtMXCiea7gg49s90Q-Qh8wHD8Ano-dPNhUawBBNEEwEbtu8toMF5k1V7Xy850EtlpZyMcS0e_y-SCJp86iM6e&wd=%E5%BD%92%E6%9D%A5&tn=baidu&ie=utf-8&inputT=2980',

    'http://www.baidu.com/link?url=TIn9NR6fwiy6IwwkCcVF8HhHoxVUpHQsyj1YdlQPy2roXKTnSQS_3UxwvyjZ2JPkpxF8-diSoRCSpODUM_jq2K&wd=%E5%BD%92%E6%9D%A5&tn=baidu&ie=utf-8&input', 

    'http://news.baidu.com/ns?cl=2&rn=20&tn=news&word=%E5%BD%92%E6%9D%A5&ie=utf-8',

    'http://image.baidu.com/i?ct=503316480&z=&tn=baiduimagedetail&ipn=d&word=%E5%BD%92%E6%9D%A5&step_word=&ie=utf-8&in=17668&cl=2&lm=-1&st=&pn=6&rn=1&di=70447907090&ln=1994&fr=news&&fmq=1402285886106_R&ic=&s=&se=&sme=0&tab=&width=&height=&face=&is=&istype=&ist=&jit=&objurl=http%3A%2F%2Fpic31.nipic.com%2F20130713%2F1287761_225159187345_2.jpg',

    'http://v.baidu.com/v?ct=301989888&s=25&ie=utf-8&word=%E5%BD%92%E6%9D%A5',

    'http://www.so.com/s?ie=utf-8&shb=1&src=360sou_newhome&q=%E5%BD%92%E6%9D%A5',

    'http://video.so.com/v?q=%E5%BD%92%E6%9D%A5&src=tab_www',

    'http://image.so.com/v?q=%E5%BD%92%E6%9D%A5&src=tab_video&fromurl=http%3A%2F%2Fndent.oeeee.com%2Fhtml%2F201309%2F16%2F258899.html',

    'http://news.so.com/ns?q=%E5%BD%92%E6%9D%A5&src=tab_video',

    'http://www.sogou.com/web?query=%E5%BD%92%E6%9D%A5&_asf=www.sogou.com&_ast=1402284372&w=01019900&p=40040100&ie=utf8&sut=6558&sst0=1402284372272&lkt=0%2C0%2C0',

    'http://www.sogou.com/web?query=%E5%BD%92%E6%9D%A5&_asf=www.sogou.com&_ast=1402284372&w=01019900&p=40040100&ie=utf8&sut=6558&sst0=1402284372272&lkt=0%2C0%2C0',

    'http://pic.sogou.com/d?query=%B9%E9%C0%B4&mood=0&picformat=0&mode=1&di=0&w=03021800&dr=1&did=1',

    'http://v.sogou.com/v?query=%B9%E9%C0%B4&p=&w=',

    'http://www.baidu.com/s?aaa=bbb',

    'http://www.baidu.com/',

    'http://www.jb51.net/',

);

foreach ($referers as $r) {

  $_SERVER['HTTP_REFERER'] = $r;

  echo getKeywords(), "\n";

}

希望本文所述对大家PHP程序设计有所帮助。