Summary of methods for requesting url in php

This article mainly introduces you to the five methods of requesting URLs in PHP, namely using the fopen() function, file() function, file_get_contents() function, curl() to request remote URL data and exec() to execute the command line. Command, let’s take a look at it below, I hope it can help everyone.

Five methods:

• The first three are PHP’s basic file operation functions

• curl( ) is the PHP extension that needs to be enabled and installed under Linux

• exec() executes the command wget under the Linux command line to download remote files

The wget command failed when testing the local virtual machine to request http://www.php.cn/, but it worked on the remote server. Considering the problem of DNS resolution, I directly requested the IP and successfully downloaded index.html. document.

Only methods are provided here. The advantages and disadvantages require a detailed understanding of the functions and defects of each method.

1. fopen() function

$file = fopen("http://www.php.cn/", "r") or die("打开远程文件失败!");
while (!feof($file)) {
 $line = fgets($file, 1024);
 //使用正则匹配标题标记
 if (preg_match("/<title>(.*)<\/title>/i", $line, $out)) { 
 $title = $out[1]; //将标题标记中的标题字符取出
 break; //退出循环，结束远程文件读取
 }
}
fclose($file);

2. file() function

$lines = file("http://www.php.cn/php-weizijiaocheng-386441.html");
readfile(http://www.php.cn/php-weizijiaocheng-386441.html);

3. file_get_contents() function

$content = file_get_contents(http://www.php.cn/php-weizijiaocheng-386441.html);

4. curl() Request remote url data

$url = "http://www.php.cn/";
$ch = curl_init();
$timeout = 5;
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
$contents = curl_exec($ch);
curl_close($ch);

5. exec() execute command line command

//exec("wget 220.181.111.188");
shell_exec("wget 220.181.111.188");

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