Php curl: how to obtain webpage content (timeout in IPV6)

Cause:
If IPv6 is enabled, curl will resolve IPv6 first by default. If the corresponding domain name does not have IPv6, curl will wait until the IPv6 dns resolution fails timeout before looking for IPv4 in the previous normal process. In the program, I set a strict timeout limit on the content obtained by curl, which may cause the problem that the content cannot be obtained.

Solution: Set the default access to ipv4.
The curl setting method for php is as follows:

<? =, CURLOPT_URL, expires, ('curlopt _ ipresolve') & ('curl _ IPRESOLVE_V4 ', expires, curl_setopt (, CURLOPT_CONNECTTIMEOUT, curl_setopt (, CURLOPT_TIMEOUT, * 3 = curl_exec ();

Note: curl_setopt ($ ch, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4) takes effect only when php version 5.3 or later, curl version 7.10.8 or later.