Differences between curl, fopen, and file_get_contents

: This article mainly introduces the differences between curl, fopen, and file_get_contents. For more information about PHP tutorials, see. Curl is mostly used to capture web pages on the Internet, fopen is mostly used to read files, while file_get_contents is mostly used to obtain static page content.

1. fopen/file_get_contents each request will re-query the DNS and will not cache the DNS information. However, CURL automatically caches DNS information. Only one DNS query is required for a webpage or image request under the same domain name. This greatly reduces the number of DNS queries. Therefore, CURL performance is much better than fopen/file_get_contents.

2. when requesting HTTP, fopen/file_get_contents uses http_fopen_wrapper instead of keeplive. But curl does. In this way, curl is more efficient when multiple links are requested.

3. curl can simulate multiple requests, such as POST data and form submission. you can customize the requests as needed. Fopen/file_get_contents can only get data.

After learning, we found that curl supports many protocols, including FTP, FTPS, HTTP, HTTPS, GOPHER, TELNET, DICT, FILE, and LDAP. that is to say, it can do a lot of things that file_get_content cannot do. Curl can remotely obtain and collect content in php; implement FTP upload and download in PHP web version; implement simulated login; implement interface connection (API), data transmission; implement Cookie simulation; resumable Upload of downloaded files.

After learning about the basic usage of curl, we can find that it is not difficult, but it is difficult to remember some parameters, but we can remember several common ones.

Enable curl:

Because PHP does not support the curl function by default, if you want to use curl, you must first. enable this function in ini, that is, remove the semicolon before extension = php_curl.dll, and then save it and restart apache/iis.

The above introduces the differences between curl, fopen and file_get_contents, including the content, and hopes to help friends who are interested in PHP tutorials.