Php functions getenv () and putenv () and $ _ SERVER

Getenv obtains the environment variable of the system.
Syntax: string getenv (string varname); ----------- the varname parameter should be $ _ SERVER (SERVER super global variable array) or use putenv ("new = very new") to define new as the environment variable. Therefore, the value of new as the parameter is very new.
Return Value: String
Function types: PHP system functions
Description: if the environment variable varname is obtained correctly, the variable value is returned. Otherwise, false is returned.
Example
In the following example, you can obtain the URL of the machine where your browser is located.

<?
$ Ip = getenv ("REMOTE_ADDR ");
?>

$ _ SERVER is the Super global variable array of the SERVER. You can use $ _ SERVER ['remote _ ADDR '] to obtain the IP address of the client.

The difference between the two is that getenv does not support php running in IIS isapi Mode

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Putenv: configure system environment variables

PHP putenv () Syntax: void putenv (string setting );

Return Value: None

Function types: PHP system functions

Description: This function is used to configure system environment variables.

Example:

The environment variable NLS_LANG to be used to configure the Oracle database. The returned data contains the Chinese BIG5 code.

<?
Putenv ("NLS_LANG = american_taiwan.zht16big5 ");
?>

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Putenv () and getenv () Examples

<? Php

Putenv ("new = very new ");
$ Is_new = getenv ("new ");
$ New = "bu shi ";

Echo $ is_new, "<br/>", $ new;

?>

Output:

Very new

So we can see from the above that we don't have to worry about defining the same name as the environment variable defined by putenv in our code, as in this example putenv ("new = very new "); like $ new = "bu shi"; ----- new, no error occurs.

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Php server variable $ _ SERVER details:

Today, I carefully studied the manual about server variables and wrote a note to help beginners.

I think the red part is more common and important. The blue part is added after debugging, which is easy to understand.

Repost, please respect the fruits of our work.

SERVER variable $ _ SERVER details:

1. $ _ SESSION ['php _ SELF '] -- get the file name of the script being executed

2. $ _ SERVER ['server _ Protocol'] -- name and version of the communication PROTOCOL when requesting the page. For example, "HTTP/1.0 ".

3. $ _ SERVER ['request _ time'] -- the timestamp at the start of the REQUEST. Valid from PHP 5.1.0. The same effect as the time function.

4. $ _ SERVER ['argv'] -- parameters passed to the script. I tried the get method to get $ _ SERVER ['argv'] [0]. The post method cannot assign a value to him.

5. $ _ SERVER ['server _ name'] -- returns the current host NAME.

6. $ _ SERVER ['server _ soft'] -- the string of the SERVER identifier, which is provided in the header information in the Response Request. For example, Microsoft-IIS/6.0

7. $ _ SERVER ['request _ method'] -- the request method used to access the page. For example, "GET", "HEAD", "POST", and "PUT ".

8. $ _ SERVER ['query _ string'] -- query string (the first question mark in the URL? ).

9. $ _ SERVER ['document _ root'] -- the ROOT directory of the DOCUMENT where the script is currently running. Defined in the server configuration file. E: \ server

10. $ _ SERVER ['HTTP _ ACCEPT '] -- Accept of the current request: header information.

11. $ _ SERVER ['HTTP _ ACCEPT_CHARSET '] -- Accept-Charset of the current request: content of the header information. Example: "iso-8859-1, *, UTF-8 ".

12. $ _ SERVER ['HTTP _ ACCEPT_ENCODING '] -- Accept-Encoding of the current request: content of the header information. For example, "gzip ".

13. $ _ SERVER ['HTTP _ ACCEPT_LANGUAGE '] -- Accept-Language of the current request: content of the header information. For example, "en ".

14. $ _ SERVER ['HTTP _ connection'] -- CONNECTION of the current request: content of the header information. For example, "Keep-Alive ".

15. $ _ SERVER ['HTTP _ host'] -- HOST of the current request: header information.

16. $ _ SERVER ['HTTP _ referer'] -- link to the URL of the previous page of the current page.

17. $ _ SERVER ['HTTP _ USER_AGENT '] -- return the browser information used by the user. You can also use get_browser () to obtain this information.

18. $ _ SERVER ['https'] -- If accessed through HTTPS, it is set to a non-null value; otherwise, off is returned.

19. $ _ SERVER ['remote _ ADDR '] -- browsing the IP address of the user on the current page.

20. $ _ SERVER ['remote _ host'] -- the HOST name of the user on the current page is being viewed. Reverse Domain name resolution is based on the user's REMOTE_ADDR. If the local test returns 127.0.0.1

21. $ _ SERVER ['remote _ port'] -- the PORT used by the user to connect to the SERVER. I did not pass the test on the local machine. I don't know why.

22. $ _ SERVER ['script _ filename'] -- the absolute path name of the currently executed SCRIPT. E: \ server \ index. php is returned.

23. $ _ SERVER ['server _ admin'] -- This value specifies the SERVER_ADMIN parameter in the Apache SERVER configuration file. If the script runs on a VM, the value is the value of that VM.

24. $ _ SERVER ['server _ port'] -- the PORT used by the SERVER. The default value is "80 ". If SSL secure connection is used, this value is the HTTP port set by the user.

25. $ _ SERVER ['server _ SIGNATURE '] -- a string containing the SERVER version and virtual host name.

26. $ _ SERVER ['path _ TRANSLATED '] -- the basic PATH of the file system where the current script is located (not the root directory of the document. This is the result of a virtual image to a real path on the server. Apache 2 users can use AcceptPathInfo On in httpd. conf to define PATH_INFO.

27. $ _ SERVER ['script _ name'] -- contains the path of the current SCRIPT. This is useful when the page needs to point to itself. _ FILE _ contains the absolute path and FILE name of the current FILE (for example, including the FILE ).

28. $ _ SERVER ['request _ URI '] -- URI required to access this page. For example, "/index.html ".

29. $ _ SERVER ['php _ AUTH_DIGEST '] -- during HTTP Digest authentication when running as an Apache module, this variable is set to the "Authorization" HTTP header content sent by the client (For further authentication ).

30. $ _ SERVER ['php _ AUTH_USER '] -- when PHP runs in the Apache or IIS (PHP 5 is an ISAPI) module and is using the HTTP authentication function, this variable is the user name entered by the user.

31. $ _ SERVER ['php _ AUTH_PW '] -- when PHP runs in the Apache or IIS (PHP 5 is an ISAPI) module and is using the HTTP authentication function, this variable is the password entered by the user.

32. $ _ SERVER ['auth _ type'] -- when PHP runs in the Apache module mode and uses the HTTP authentication function, this variable is the authentication TYPE.