PHP uses CURL to capture web pages with multiple threads

PHP uses CURL to capture web pages with multiple threads

PHP uses Curl Functions to complete various file transfer operations, such as simulating a browser to send GET and POST requests. Due to the fact that php does not support multithreading, it is inefficient to develop crawler programs, at this time, you often need to use Curl Multi Functions to implement concurrent Multi-threaded access to multiple URLs. Since Curl Multi Function is so powerful, can I use Curl Multi Functions to write concurrent Multi-threaded download files? Of course, the following code is provided:

Code 1: Write the obtained Code directly to a file

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<? Php $ Urls = array ( 'Http: // www.sina.com.cn /', 'Http: // www.sohu.com /', 'Http: // www.163.com /' ); // Set the URL of the page to be crawled   $ Save_to = '/test.txt'; // write the captured code to this file   $ St = fopen ($ save_to, ""); $ Mh = curl_multi_init ();   Foreach ($ urls as $ I =>$ url ){ $ Conn [$ I] = curl_init ($ url ); Curl_setopt ($ conn [$ I], CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0 )"); Curl_setopt ($ conn [$ I], CURLOPT_HEADER, 0 ); Curl_setopt ($ conn [$ I], CURLOPT_CONNECTTIMEOUT, 60 ); Curl_setopt ($ conn [$ I], CURLOPT_FILE, $ st); // you can write the crawled code to a file. Curl_multi_add_handle ($ mh, $ conn [$ I]); } // Initialization   Do { Curl_multi_exec ($ mh, $ active ); } While ($ active); // Execute   Foreach ($ urls as $ I =>$ url ){ Curl_multi_remove_handle ($ mh, $ conn [$ I]); Curl_close ($ conn [$ I]); } // End cleaning   Curl_multi_close ($ mh ); Fclose ($ st ); ?>

Code 2: Put the obtained code into a variable before writing it to a file.

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<? Php $ Urls = array ( 'Http: // www.sina.com.cn /', 'Http: // www.sohu.com /', 'Http: // www.163.com /' );   $ Save_to = '/test.txt'; // write the captured code to this file $ St = fopen ($ save_to, "");   $ Mh = curl_multi_init (); Foreach ($ urls as $ I =>$ url ){ $ Conn [$ I] = curl_init ($ url ); Curl_setopt ($ conn [$ I], CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0 )"); Curl_setopt ($ conn [$ I], CURLOPT_HEADER, 0 ); Curl_setopt ($ conn [$ I], CURLOPT_CONNECTTIMEOUT, 60 ); Curl_setopt ($ conn [$ I], CURLOPT_RETURNTRANSFER, true); // you can convert the crawler code into a string instead of writing it to the browser. Curl_multi_add_handle ($ mh, $ conn [$ I]); }   Do { Curl_multi_exec ($ mh, $ active ); } While ($ active );   Foreach ($ urls as $ I =>$ url ){ $ Data = curl_multi_getcontent ($ conn [$ I]); // obtain the crawled code string Fwrite ($ st, $ data); // write a string to a file. Of course, you can also not write files, such as saving them to the database. } // Get the data variable and write it to the file   Foreach ($ urls as $ I =>$ url ){ Curl_multi_remove_handle ($ mh, $ conn [$ I]); Curl_close ($ conn [$ I]); }   Curl_multi_close ($ mh ); Fclose ($ st ); ?>

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