Introduction to the functions of PHP's cURL library: crawling web pages, POST data and others

Introduction to the functions of PHP's cURL library: crawling web pages, POST data and others_PHP tutorial

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Release： 2016-07-21 15:30:34

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Whether you want to retrieve partial data from a link, take an XML file and import it into a database, or even simply retrieve the content of a web page, cURL is a powerful PHP library. This article mainly describes how to use this PHP library.
Enable cURL settings
First, we must first determine whether our PHP has this library enabled. You can get this information by using the php_info() function.

Copy code The code is as follows:

 
phpinfo(); 
?> 

If you can see the following output on the web page, it means that the cURL library has been enabled.
If you see this, then you need to set up your PHP and enable this library. If you are on the Windows platform, it is very simple. You need to change the settings of your php.ini file, find php_curl.dll, and cancel the previous semicolon comment. As shown below:
//Uncomment the following
extension=php_curl.dll

If you are under Linux, then you need to recompile your PHP when editing. , you need to turn on the compilation parameters - add the "-with-curl" parameter to the configure command.
　A small example
If everything is ready, here is a small routine:

Copy the code The code is as follows:

 
// Initialize a cURL object 
$curl = curl_init(); 
// Set the URL you need to crawl 
curl_setopt($curl, CURLOPT_URL, 'http: //jb51.net'); 
// Set header 
curl_setopt($curl, CURLOPT_HEADER, 1); 
// Set cURL parameters to require the result to be saved in a string or output to the screen. 
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1); 
// Run cURL and request the web page
$data = curl_exec($curl); 
// Close URL request
curl_close($curl ; POST data. Suppose we have a form processing URL http://www.example.com/sendSMS.php, which can accept two form fields, one is a phone number and the other is text message content. 

Copy code

The code is as follows:

$phoneNumber　='13912345678'; $ message = 'This message was generated by curl and php'; $curlPost = 'pNUMBER=' . urlencode($phoneNumber) . '&MESSAGE=' . urlencode($message) . $ch = curl_init();chain link fencing

curl_setopt($ch, CURLOPT_URL, 'http://www.example.com/sendSMS.php');

curl_setopt($ch, CURLOPT_HEADER, 1); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch, CURLOPT_POST, 1); 
curl_setopt($ch, CURLOPT_POSTFIELDS, $curlPost); 
$data = curl_exec(); 
curl_close($ch); 
?> 

 
 From the above program we can see that use CURLOPT_POST to set the POST method of the HTTP protocol instead of the GET method, and then use CURLOPT_POSTFIELDS Set POST data. 
　About proxy server 
　The following is an example of how to use a proxy server. Please pay attention to the highlighted code. The code is very simple, so I don’t need to say more. 

Copy code

The code is as follows:

$ch　= curl_init(); curl_setopt ($ch, CURLOPT_URL, 'http://www.example.com'); curl_setopt($ch, CURLOPT_HEADER, 1); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); $ch, CURLOPT_HTTPPROXYTUNNEL, 1);

curl_setopt($ch, CURLOPT_PROXY, 'fakeproxy.com:1080'); curl_exec();

curl_close($ch); 
?> 

　 
 About SSL and Cookies 
 About SSL, which is the HTTPS protocol, for gas generators, you only need to put CURLOPT_URL Just change the http:// in the connection to https://. Of course, there is also a parameter called CURLOPT_SSL_VERIFYHOST that can be set to verify the site. 
 About Cookies, you need to know the following three parameters: 
 CURLOPT_COOKIE, set a cookie in the face-to-face session 
 CURLOPT_COOKIEJAR, save a Cookie when the session ends 
 CURLOPT_COOKIEFILE, Cookie file. 
 HTTP server authentication 
 Finally, let’s take a look at HTTP server authentication. 

Copy code

The code is as follows:

 
$ch = curl_init(); 
curl_setopt($ch, CURLOPT_URL, 'http://www.example.com'); 
curl_setopt($ch , CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC); 
curl_setopt(CURLOPT_USERPWD, '[username]:[password]') 
$data = curl_exec(); 
curl_close ($ch); 
?> 

For more information, please refer to the relevant cURL manual.