What are the functions of php curl? Application of php curl library (with code)

WeChat Weibo official account, QQ official account, maps and many third-party functions are provided to developers in the form of HTTP API (application). So, how to request third-party APIs such as WeChat and Maps? At this time, you need to use cURL. This article will introduce to you the application of the php curl library.

cURL is translated into Chinese as a URL-based function library. Its main function is: use related functions to simulate protocol requests.

For example:

1. Simulate the form to send data to an address

2. Without verification code Simulate the form to complete the user login

3. Upload a file to the remote server

4. Request certain functions provided by the remote server
   ... ...

curl supports dict, file, ftp, ftps, gopher, http, https, imap, imaps, ldap, ldaps, pop3, pop3s, rtmp, rtsp, smtp, smtps, telnet and tftp protocols.
curl also supports HTTPS authentication, HTTP POST, HTTP PPUT, FTP upload (this can also be completed through PHP's FTP extension), HTTP form-based upload, proxy, cookies and username and password authentication.

1. Initial use of curl resources

There is only one sentence, that is, the curl_init function is used. This parameter method requires any parameters to be passed in. Returns curl's operating resources.

Because, we later push data into curl's operating resource variables through curl_setopt.

Example:

$ch = curl_init();

2. Parameter setting request protocol address

The detailed usage of the curl_setopt function is as follows:

type	illustrate
Function	curl_setopt
Parameter 1	curl resource variables
Parameter 2	curl parameter options
Parameter 3	curl parameter value

CURLOPT_URL This parameter option specifies the requested url address.

curl_setopt($ch, CURLOPT_URL, "http://www.php.cn");

3. Whether the parameter setting returns the request result

We hope that the curl request will return the corresponding result. If we want to get the corresponding result, we also need to set a parameter. This parameter is called: CURLOPT_RETURNTRANSFER.

If required, the return value is 1. The result returned after no request can be set to 0.

curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

4. Set the sending data

If it is a get request, we do not need to set the sending parameters. When posting and waiting for requests, we need to set the sending method to the post method. and set the data to be sent.

*CURLOPT_POST *Set the value to 1 to use the POST method, and 0 to not use the POST method

CURLOPT_POSTFIELDSSet the passed data

//声明使用POST方式来进行发送
    curl_setopt($ch, CURLOPT_POST, 1);
//发送什么数据呢
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

5. Other parameter information settings

If it is https, sometimes we need to ignore the security certificate of https.

CURLOPT_SSL_VERIFYPEER and CURLOPT_SSL_VERIFYHOST are changed to false to ignore the certificate.

curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);

CURLOPT_HEADER This parameter also determines whether to process http header information. If we do not want to receive processing, we can set this value to 0.

curl_setopt($ch, CURLOPT_HEADER, 0);

In addition, we can also set the timeout of the request, the parameter is: CURLOPT_TIMEOUT.

curl_setopt($ch, CURLOPT_TIMEOUT, 10);

There are many other parameters. If necessary, you can visit www.php.cn

6. Execute or execute php curl to get the return result

We In the third step, set the value of the CURLOPT_RETURNTRANSFER parameter to 1. If the execution result has data. After execution using curl_exec, the result will be returned to the $output variable.

$output = curl_exec($ch);

7. Close curl resources

Close curl resources. Because of the resource type, we have repeatedly emphasized that if it is opened, it will be closed.

If you don’t need to use it, use curl_close to close it and release the memory immediately.

curl_close($ch);

8. Put the above together

Recommended related articles:

curl introduction and curl in php

The solution to error reporting using CURL in PHP rip curl php curl Open curl under curl

A brief introduction to CURL in PHP

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