Detailed explanation of usage examples of PHP curl_exec function

What does the curl_exec function do?

php The curl_exec function is one of the PHP cURL function lists. Its function is to execute a cURL session. Now that you know the function of php curl_exec function, let’s learn about What is CURL

CURL is a very powerful open source library that supports many protocols, including HTTP, FTP, TELNET, etc. We use it to send HTTP requests. The benefit it brings to us is that we can set different HTTP protocol parameters through flexible options, and

and supports HTTPS. CURL can automatically choose whether to encrypt the sent content based on whether the URL prefix is ​​"HTTP" or "HTTPS".

Let’s take a look at the syntax description of php curl_exec function

mixed curl_exec ( resource $ch )

Detailed syntax explanation:

Execute a given cURL session .

This function should be called after a cURL session is initialized and all options are set.

Parameters

ch

The cURL handle returned by curl_init().

The return value of the curl_exec function

returns TRUE on success, or FALSE on failure. However, if The CURLOPT_RETURNTRANSFER option is set, and the execution result will be returned when the function is successfully executed, and FALSE is returned when it fails.

Example

Get a web page

<?php
// 创建一个cURL资源
$ch = curl_init();

// 设置URL和相应的选项
curl_setopt($ch, CURLOPT_URL, "http://www.php.cn/");
curl_setopt($ch, CURLOPT_HEADER, 0);

// 抓取URL并把它传递给浏览器
curl_exec($ch);

// 关闭cURL资源，并且释放系统资源
curl_close($ch);
?>

Code running results:

Four functions are used in the above example code

curl_init() and curl_close() are initialization respectively CURL connection and closing CURL connection are relatively simple.

curl_exec() executes a CURL request. If no error occurs, the function returns the data returned by the corresponding URL, expressing satisfaction as a string; if an error occurs, the function returns FALSE. It should be noted that the equal sign is used to determine whether the output is FALSE. This is to distinguish between returning an empty string and an error.

The most important function in the CURL function library is curl_setopt(), which can customize HTTP requests by setting options defined by the CURL function library. Three important options are used in the above code snippet:

CURLOPT_URL specifies the requested URL;

CURLLOPT_HEADER is set to 0 to indicate that no HTTP header information is returned.

CURL has many options. For details, you can view the reference manual of CURL

[Recommended tutorials]

1. " php.cn Dugu Jiujian (4)-php video tutorial》

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