Quickly understand the techniques of crawling web content with PHP

How to correctly implement phpto capture web content? This problem is a bit difficult for friends who have not been exposed to PHP language for a long time. KekejieToday I will introduce you to the specific solution.

First, I opened the extension=php_curl.dll function in php.ini in Cwindows, and then restarted apache. The following is the PHP I wrote to capture web content and capture the PHP information in Baidu:

| /setURL Parameters

　curl_setopt($ch,CURLOPT_URL,"http: //http://www.baidu.com/s?wd=php");

　　 //Require CURL to return data

　curl_setopt ($ch,CURLOPT_RETURNTRANSFER,1);

　　 //Execute the request

　 $result = curl_exec($ch) or die (curl_error());

　　 //Get the returned result and display it

　 echo $result;

　 echo curl_error($ch);

　　 //Close CURL

　 curl_close($ch);

　?>

　But why? Why is there no response after PHP grabs the web content? There is no test text. If I put echo "test"; on the first line, it can be output. I guess the curl_init() function has not been run yet!

See if there is CURL extension support in PHP's phpinfo()!

Copy php_curl.dll to c:windows and c:windowssystem32 and restart apache and try again

It is not the file php_curl.dll. Copy libeay32.dll and ssleay32.dll in the php directory to c:windowssystem32 and restart apache. For the sake of server security, allow_url_fopen is turned off.

　 When the server allow_url_fopen = Off, file_get_contents cannot be used. It can only be used when it is set to ON.

　　< ?php /*

　 $getstr=file_get_contents("http://www. 163.com/weatherxml/54511.xml");

　 $qx=explode(""",strstr($getstr,"qx="));

　 $wd=explode(""",strstr($getstr,"wd="));

　 $qximg=explode(""",strstr($getstr,"qximg="));

　 $qximg_=explode(",",$qximg[1]);

echo "Beijing ".$qx[1]."";

　 echo $wd[1];*/

　 //echo "< img src='http://news. 163.com/img/ logo/".$qximg_[0]."'> < img src='http://news.163.com /img/logo/".$qximg_[1]."'>";

　　?>

　 The following example of PHP crawling web content is to obtain the 163 weather forecast through the curl_init function

　 Remove the (;) in front of php.ini ( ;extension=php_curl.dll ) and save

　Copy php_curl.dll, libeay32.dll, ssleay32.dll to c:windowssystem32 and restart IIS. Apache is not installed

　　< ?php

　

　 $ch = curl_init() or die (curl_error());

　　 //Set URL parameters

　 curl_setopt($ch,CURLOPT_URL,"http: //http://www.163.com/ weatherxml/54511.xml");

　　 //Request CURL to return data

　 curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);

　　 //Execute the request

​$result = curl_exec($ ch) or die (curl_error());

　　 //Get the returned result and display

　 //echo $result;

　　 // echo curl_error($ch);

$qx=explode(""",strstr($result,"qx="));

　 $wd=explode(""",strstr($result,"wd="));

$qximg=explode(""",strstr($result,"qximg="));

　 $qximg_=explode(",",$qximg[1]);

echo "Beijing". $qx[1]."< br />";

　 echo $wd[1];

　　 //Close CURL

　 curl_close($ch);

　　?> ;

Through the above study of PHP crawling web content, you can practice it yourself and deepen your understanding of it. More related information: http://www.kokojia.com/s64/