curl Setting Timeout Instance of php

In this paper, the timeout setting method of curl in php is described as an example. Share it for your reference. The specific implementation method is as follows:

There are many ways to access HTTP, such as curl, socket, file_get_contents (), etc.
When accessing http, you need to consider the problem of timeout.

CURL Access HTTP:

CURL is a commonly used lib library for accessing HTTP protocol interface, with high performance and some concurrent support functions.
curl_setopt ($ch, opt) can set some timeout settings, mainly including:
① (Important) CURLOPT_TIMEOUT Sets the maximum number of seconds cURL is allowed to execute.
② (Important) CURLOPT_TIMEOUT_MS Sets the maximum number of milliseconds that cURL is allowed to execute.
(Added in cURL 7.16. 2. Available from PHP 5.2. 3)
③ The waiting time of CURLOPT_CONNECTTIMEOUT before initiating the connection. If it is set to 0, it will wait indefinitely.
CURLOPT_CONNECTTIMEOUT_MS wait time, in milliseconds, for connection attempts. If set to 0, it waits indefinitely. (Added in cURL 7.16. 2. Available from PHP 5.2. 3)
⑤ CURLOPT_DNS_CACHE_TIMEOUT sets the time to save DNS information in memory, and the default is 120 seconds.

1. curl normal second timeout:

 $ch = curl_init();      

 curl_setopt($ch, CURLOPT_URL,$url);       

 curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);       

 curl_setopt($ch, CURLOPT_TIMEOUT,60);   // You only need to set 1 The number of seconds will be fine   

 curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);       

 curl_setopt($ch, CURLOPT_USERAGENT, $defined_vars['HTTP_USER_AGENT']); 

2. curl normal second timeout use:

 curl_setopt($ch, CURLOPT_TIMEOUT,60);

3. If the millisecond timeout is required for curl, it needs to be added:

 curl_easy_setopt(curl, CURLOPT_NOSIGNAL,1L);      

 // Or       

 curl_setopt ( $ch,  CURLOPT_NOSIGNAL,true);// Support millisecond timeout setting 

I hope this article is helpful to everyone's PHP programming.