Php fopen function cannot obtain remote address content

Fopen functions are mostly used to read and write files in php, but are sometimes used to obtain files from remote servers. However, when using fopen to read remote files, you must enable allow_url_fopen.

Solution Process

First, the DNS problem is ruled out, because everything except these functions works normally. Although it is a URL with a domain name, The gethostbyname () function returns a correct result. Then I thought about the configuration of php. ini -- but I found that allow_url_fopen has been enabled. Later, I asked Google for help. Some people mentioned SELINUX. But I didn't open SELINUX at all. Continue to Google and find StackOverflow

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$ File = fopen ('HTTP: // www.google.com/', 'rb '); Var_dump (stream_get_meta_data ($ file )); /* Output result: Array (10 ){ ["Wrapper_data"] => Array (2 ){ ["Headers"] => Array (0 ){ } ["Readbuf"] => Resource (38) of type (stream) } ["Wrapper_type"] => String (4) "cURL" ["Stream_type"] => String (4) "cURL" ["Mode"] => String (2) "rb" ["Unread_bytes"] => Int (0) ["Seekable"] => Bool (false) ["Uri"] => String (23) "http://www.google.com /" ["Timed_out"] => Bool (false) ["Blocked"] => Bool (true) ["Eof"] => Bool (false) }*/

To use functions such as fopen, getimagesize, or include to open a url, you need. ini settings, usually set allow_url_fopen to on to allow fopen url, set allow_url_include to on to allow include/require url, but it may not work in local test environment.

Allow_url_fopen = on

Whether to allow the treatment of URLs (like http: // or ftp: //) as files.

Allow_url_include = on

Whether to allow include/require to open URLs (like http: // or ftp: //) as files.

In the local wamp test environment, after this setting, fopen can open the remote address normally, but an error will be reported in case of a local address, such

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1 fopen ("http: // localhost/myfile. php", "r ");

An error is reported after the maximum execution time of the script set in php. ini is exceeded, indicating that the file does not exist. This won't happen on the online server, but it works normally if you replace localhost with 127.0.0.1.

According to the situation, the problem lies in DNS resolution. It is said that localhost has been automatically mapped to 127.0.0.1. In fact, accessing http: // localhost and accessing http: // 127.0.0.1 also reach the same address.

The solution is to check the Windows host file, which is usually located in the system32 directory. A system disk is the host path of drive C as follows:

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C:/Windows/System32/drivers/etc/hosts

Open the hosts file and use notepad, notepad ++, and other tools.

Remove the # Above 127.0.0.1.

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# Localhost name resolution is handled within DNS itself. #127.0.0.1 localhost

What is the use of a url as a file?
For example, you can pass a value to an include file.

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<? Php include 'HTTP: // yourdomain.com/example. inc. php? Foo = 1 & bar = 2';?>

In example. inc. php

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<? Php Var_dump ($ _ GET ['foo']); Var_dump ($ _ GET ['bar']); ?>

Running result

String (1) "1" string (1) "2"