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$_SERVER

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

$_SERVERサーバー情報および実行時の環境情報

説明

$_SERVER は、ヘッダ、パス、スクリプトの位置のような 情報を有する配列です。この配列のエントリは、Web サーバーにより 生成されます。全ての Web サーバーがこれら全てを提供する保証はありません。 サーバーは、これらのいくつかを省略したり、この一覧にない他のものを 定義する可能性があります。しかし、これらの変数のほとんどは、 » CGI/1.1 specification で定義されています。したがって、これらのほとんどは定義されていることを 期待することができます。

注意: PHP を コマンドライン から実行している場合、 これらの変数のほとんどは利用できないか、 なんの意味も持ちません。

以下に示された要素に加え、 PHP はリクエストヘッダから追加の要素を生成します。 それらの要素は HTTP_ で始まり、 その後にヘッダの名前が続き、 かつ大文字に変換され、ハイフンがアンダースコアになります。 たとえば、 Accept-Language ヘッダは $_SERVER['HTTP_ACCEPT_LANGUAGE'] として利用可能です。

インデックス

'PHP_SELF'
現在実行しているスクリプトのファイル名です。 ドキュメントルートから取得されます。 例えば、http://example.com/foo/bar.php というアドレス上にあるスクリプトでは $_SERVER['PHP_SELF']/foo/bar.php となります。 __FILE__ 定数 には、カレント(すなわち読み込まれた)ファイルのパスとファイル名が含まれます。 PHP がコマンドラインから実行される場合、 この変数にはスクリプト名が含まれます。
'argv'
スクリプトに渡された引数の配列です。スクリプトがコマンドラインから 実行された場合、C 言語スタイルでコマンドライン引数に アクセスすることができます。GET メソッドを通してコールされた場合には 検索引数が格納されます。
'argc'
スクリプトに渡されたコマンドライン引数の数 (コマンドラインから実行した場合) です。
'GATEWAY_INTERFACE'
サーバーが使用している CGI のバージョンです。 例 'CGI/1.1'
'SERVER_ADDR'
現在のスクリプトが実行されているサーバーの IP アドレスです。
'SERVER_NAME'
現在のスクリプトが実行されているサーバーのホスト名です。 スクリプトがバーチャルホスト上で実行されている場合は そのバーチャルホスト名となります。

注意: Apache 2 では、UseCanonicalName = OnServerName を設定する必要があります。 そうしなければ、この値はクライアントが提供するホスト名を指すようになってしまい、無意味です。 また、セキュリティ的な意味合いでこの値に頼ってはいけません。

'SERVER_SOFTWARE'
レスポンスヘッダ上に書かれている、 サーバーの認識文字列です。
'SERVER_PROTOCOL'
ページがリクエストされた際のプロトコル名とバージョンです。 例. 'HTTP/1.0'
'REQUEST_METHOD'
ページにアクセスする際に使用されたリクエストのメソッド名です。 'GET', 'HEAD', 'POST', 'PUT' など。

注意:

リクエストのメソッドが HEAD だった場合、 PHP スクリプトはヘッダを送信した後(言い換えれば、 出力バッファリングを行わずに全出力を処理した後)に終了します。

'REQUEST_TIME'
リクエストの開始時のタイムスタンプ。
'REQUEST_TIME_FLOAT'
リクエストの開始時のタイムスタンプ (マイクロ秒までの精度)。
'QUERY_STRING'
ページがアクセスされた際にもし検索引数があればそれが格納されます。
'DOCUMENT_ROOT'
現在実行されているスクリプトが存在するドキュメントルート ディレクトリです。サーバーのコンフィグレーションファイルで 定義されています。
'HTTPS'
スクリプトが HTTPS プロトコルを通じて実行されている場合に 空でない値が設定されます。
'REMOTE_ADDR'
現在ページをみているユーザーの IP アドレス。
'REMOTE_HOST'
現在のページにアクセスしているホスト名。DNS の逆引き検索は ユーザーの REMOTE_ADDR に基づいています。

注意: Web サーバーがこの値を生成できるように設定されている必要があります。 例えば Apache の場合 HostnameLookups Onhttpd.conf に設定されていなければこの値は生成されません。 gethostbyaddr() もご覧ください。

'REMOTE_PORT'
ユーザーのマシンから Web サーバーへの通信に使用されているポート番号
'REMOTE_USER'
認証されたユーザー。
'REDIRECT_REMOTE_USER'
リクエストが内部でリダイレクトされた場合の認証されたユーザー。
'SCRIPT_FILENAME'

現在実行されているスクリプトの絶対パス

注意:

file.php あるいは ../file.php のような相対パスを指定して CLI でスクリプトが実行されている場合、 $_SERVER['SCRIPT_FILENAME'] には ユーザーが指定した相対パスが含まれます。

'SERVER_ADMIN'
Web サーバーの設定ファイルの SERVER_ADMIN (Apache の場合)ディレクティブ にセットされている値。スクリプトがバーチャルホスト上で 実行されている場合、バーチャルホストに対して値が定義されます。
'SERVER_PORT'
Web サーバーの通信ポートとして使用されているポート番号。デフォルトでは '80' ですが、例えば SSL を使用している場合は セキュア HTTP ポートとして設定されている値に変わります。

注意: Apache 2 では、UseCanonicalName = On だけでなく UseCanonicalPhysicalPort = On も設定しないと物理ポート (実際のポート) を取得できません。設定しなければ、 この値は詐称できる状態になり、 物理ポートを返さなくなるかもしれません。 セキュリティに依存するコンテキストで、この値に頼るのは安全ではありません。

'SERVER_SIGNATURE'
サーバー上で生成されたページに追加される、 サーバーのバージョン名とバーチャルホスト名の文字列。 Web サーバーの設定で有効になっていることが必要です。
'PATH_TRANSLATED'
バーチャルからリアルへのマッピングがなされた後の、 現在のスクリプトのファイルシステム上(ドキュメントルートではなく) でのパス。

注意: Apache 2 ユーザーは、PATH_INFO を定義するために httpd.conf の中で AcceptPathInfo = On を使用することが可能です。

'SCRIPT_NAME'
現在のスクリプトのパス。 スクリプト自身のページを指定するのに有用です。 __FILE__ 定数には、カレント(すなわち読み込まれた)ファイルのパスとファイル名が 含まれます。
'REQUEST_URI'
ページにアクセスするために指定された URI。例えば、 '/index.html'
'PHP_AUTH_DIGEST'
HTTP ダイジェスト認証を 行っている場合、クライアントから送られた 'Authorization' ヘッダの 内容が設定されます(適切な認証処理を行うために利用します)。
'PHP_AUTH_USER'
HTTP 認証しているときにそのユーザー名がセットされます。
'PHP_AUTH_PW'
HTTP 認証しているときにそのユーザーの パスワードがセットされます。
'AUTH_TYPE'
HTTP 認証しているときにその認証形式がセットされます。
'PATH_INFO'
実際のスクリプトファイル名とクエリ文字列の間にある、クライアントが提供するパス名情報。 たとえば、現在のスクリプトに http://www.example.com/php/path_info.php/some/stuff?foo=bar という URI でアクセスしていた場合の $_SERVER['PATH_INFO']/some/stuff となります。
'ORIG_PATH_INFO'
PHP で処理される前の 'PATH_INFO' の原本。

例1 $_SERVER の例

<?php
echo $_SERVER['SERVER_NAME'];
?>

上の例の出力は、 たとえば以下のようになります。

www.example.com

注意

注意:

これは 'スーパーグローバル' あるいは自動グローバル変数と呼ばれるものです。 スクリプト全体を通してすべてのスコープで使用することができます。 関数やメソッドの内部で使用する場合にも global $variable; とする必要はありません。

add a note

User Contributed Notes 40 notes

up
144
Vladimir Kornea
15 years ago
1. All elements of the $_SERVER array whose keys begin with 'HTTP_' come from HTTP request headers and are not to be trusted.

2. All HTTP headers sent to the script are made available through the $_SERVER array, with names prefixed by 'HTTP_'.

3. $_SERVER['PHP_SELF'] is dangerous if misused. If login.php/nearly_arbitrary_string is requested, $_SERVER['PHP_SELF'] will contain not just login.php, but the entire login.php/nearly_arbitrary_string. If you've printed $_SERVER['PHP_SELF'] as the value of the action attribute of your form tag without performing HTML encoding, an attacker can perform XSS attacks by offering users a link to your site such as this:

<a href='http://www.example.com/login.php/"><script type="text/javascript">...</script><span a="'>Example.com</a>

The javascript block would define an event handler function and bind it to the form's submit event. This event handler would load via an <img> tag an external file, with the submitted username and password as parameters.

Use $_SERVER['SCRIPT_NAME'] instead of $_SERVER['PHP_SELF']. HTML encode every string sent to the browser that should not be interpreted as HTML, unless you are absolutely certain that it cannot contain anything that the browser can interpret as HTML.
up
57
vcoletti at tiscali dot it
4 years ago
To list all the $_SERVER parameters, simply do:

foreach ($_SERVER as $parm => $value) echo "$parm = '$value'\n";

No need to list all possible keys of the array.
up
39
Lord Mac
14 years ago
An even *more* improved version...

<?php
phpinfo
(32);
?>
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34
MarkAgius at markagius dot co dot uk
12 years ago
You have missed 'REDIRECT_STATUS'

Very useful if you point all your error pages to the same file.

File; .htaccess
# .htaccess file.

ErrorDocument 404 /error-msg.php
ErrorDocument 500 /error-msg.php
ErrorDocument 400 /error-msg.php
ErrorDocument 401 /error-msg.php
ErrorDocument 403 /error-msg.php
# End of file.

File; error-msg.php
<?php
$HttpStatus
= $_SERVER["REDIRECT_STATUS"] ;
if(
$HttpStatus==200) {print "Document has been processed and sent to you.";}
if(
$HttpStatus==400) {print "Bad HTTP request ";}
if(
$HttpStatus==401) {print "Unauthorized - Iinvalid password";}
if(
$HttpStatus==403) {print "Forbidden";}
if(
$HttpStatus==500) {print "Internal Server Error";}
if(
$HttpStatus==418) {print "I'm a teapot! - This is a real value, defined in 1998";}

?>
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24
pierstoval at example dot com
6 years ago
As PHP $_SERVER var is populated with a lot of vars, I think it's important to say that it's also populated with environment vars.

For example, with a PHP script, we can have this:

MY_ENV_VAR=Hello php -r 'echo $_SERVER["MY_ENV_VAR"];'

Will show "Hello".

But, internally, PHP makes sure that "internal" keys in $_SERVER are not overriden, so you wouldn't be able to do something like this:

REQUEST_TIME=Hello php -r 'var_dump($_SERVER["REQUEST_TIME"]);'

Will show something like 1492897785

However, a lot of vars are still vulnerable from environment injection.

I created a gist here ( https://gist.github.com/Pierstoval/f287d3e61252e791a943dd73874ab5ee ) with my PHP configuration on windows with PHP7.0.15 on WSL with bash, the results are that the only "safe" vars are the following:

PHP_SELF
SCRIPT_NAME
SCRIPT_FILENAME
PATH_TRANSLATED
DOCUMENT_ROOT
REQUEST_TIME_FLOAT
REQUEST_TIME
argv
argc

All the rest can be overriden with environment vars, which is not very cool actually because it can break PHP applications sometimes...

(and I only tested on CLI, I had no patience to test with Apache mod_php or Nginx + PHP-FPM, but I can imagine that not a lot of $_SERVER properties are "that" secure...)
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22
jonbarnett at gmail dot com
15 years ago
It's worth noting that $_SERVER variables get created for any HTTP request headers, including those you might invent:

If the browser sends an HTTP request header of:
X-Debug-Custom: some string

Then:

<?php
$_SERVER
['HTTP_X_DEBUG_CUSTOM']; // "some string"
?>

There are better ways to identify the HTTP request headers sent by the browser, but this is convenient if you know what to expect from, for example, an AJAX script with custom headers.

Works in PHP5 on Apache with mod_php. Don't know if this is true from other environments.
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13
chris at ocproducts dot com
6 years ago
Guide to absolute paths...

Data: __FILE__
Data type: String
Purpose: The absolute pathname of the running PHP file, including the filename.
Caveat: This is not the file called by the PHP processor, it's what is running. So if you are inside an include, it's the include.
Caveat: Symbolic links are pre-resolved, so don't trust comparison of paths to be accurate.
Caveat: Don't assume all operating systems use '/' for the directory separator.
Works on web mode: Yes
Works on CLI mode: Yes

Data: __DIR__
Data type: String
Purpose: The absolute pathname to the running PHP file, excluding the filename
Caveat: This is not the file called by the PHP processor, it's what is running. So if you are inside an include, it's the include.
Caveat: Symbolic links are pre-resolved, so don't trust comparison of paths to be accurate.
Caveat: Don't assume all operating systems use '/' for the directory separator.
Works on web mode: Yes
Works on CLI mode: Yes

Data: $_SERVER['SCRIPT_FILENAME']
Data type: String
Purpose: The absolute pathname of the origin PHP file, including the filename
Caveat: Not set on all PHP environments, may need setting by copying from __FILE__ before other files are included.
Caveat: Symbolic links are not pre-resolved, use PHP's 'realpath' function if you need it resolved.
Caveat: Don't assume all operating systems use '/' for the directory separator.
Caveat: "Filename" makes you think it is just a filename, but it really is the full absolute pathname. Read the identifier as "Script's filesystem (path)name".
Works on web mode: Yes
Works on CLI mode: Yes

Data: $_SERVER['PATH_TRANSLATED']
Data type: String
Purpose: The absolute pathname of the origin PHP file, including the filename
Caveat: It's probably not set, best to just not use it. Just use realpath($_SERVER['SCRIPT_FILENAME']) (and be aware that itself may need to have been emulated).
Caveat: Symbolic links are pre-resolved, so don't trust comparison of paths to be accurate.
Caveat: Don't assume all operating systems use '/' for the directory separator.
Works on web mode: Yes
Works on CLI mode: No

Data: $_SERVER['DOCUMENT_ROOT']
Data type: String
Purpose: Get the absolute path to the web server's document root. No trailing slash.
Caveat: Don't trust this to be set, or set correctly, unless you control the server environment.
Caveat: May or may not have symbolic links pre-resolved, use PHP's 'realpath' function if you need it resolved.
Caveat: Don't assume all operating systems use '/' for the directory separator.
Works on web mode: Yes
Works on CLI mode: No

Note that if something is not set it may be missing from $_SERVER, or it may be blank, so use PHP's 'empty' function for your test.

Note that if you call "php --info" on the command line then naturally some of these settings are going to be blank, as no PHP file is involved.
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20
Richard York
14 years ago
Not documented here is the fact that $_SERVER is populated with some pretty useful information when accessing PHP via the shell.

["_SERVER"]=>
array(24) {
["MANPATH"]=>
string(48) "/usr/share/man:/usr/local/share/man:/usr/X11/man"
["TERM"]=>
string(11) "xterm-color"
["SHELL"]=>
string(9) "/bin/bash"
["SSH_CLIENT"]=>
string(20) "127.0.0.1 41242 22"
["OLDPWD"]=>
string(60) "/Library/WebServer/Domains/www.example.com/private"
["SSH_TTY"]=>
string(12) "/dev/ttys000"
["USER"]=>
string(5) "username"
["MAIL"]=>
string(15) "/var/mail/username"
["PATH"]=>
string(57) "/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin"
["PWD"]=>
string(56) "/Library/WebServer/Domains/www.example.com/www"
["SHLVL"]=>
string(1) "1"
["HOME"]=>
string(12) "/Users/username"
["LOGNAME"]=>
string(5) "username"
["SSH_CONNECTION"]=>
string(31) "127.0.0.1 41242 10.0.0.1 22"
["_"]=>
string(12) "/usr/bin/php"
["__CF_USER_TEXT_ENCODING"]=>
string(9) "0x1F5:0:0"
["PHP_SELF"]=>
string(10) "Shell.php"
["SCRIPT_NAME"]=>
string(10) "Shell.php"
["SCRIPT_FILENAME"]=>
string(10) "Shell.php"
["PATH_TRANSLATED"]=>
string(10) "Shell.php"
["DOCUMENT_ROOT"]=>
string(0) ""
["REQUEST_TIME"]=>
int(1247162183)
["argv"]=>
array(1) {
[0]=>
string(10) "Shell.php"
}
["argc"]=>
int(1)
}
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10
ywarnier at beeznest dot org
6 years ago
Note that $_SERVER['REQUEST_URI'] might include the scheme and domain in certain cases.

This happens, for example, when calling the page through a call to stream_context_create() with a HTTP header of 'request_fulluri' set to 1.

For example:

$http = ['request_fulluri' => 1, /* other params here */];
$context = stream_context_create(array( 'http' => $http ));
$fp = fopen($some_url, 'rb', false, $context);

When outputting $_SERVER['REQUEST_URI'] on the server at $some_url, you will get
https://some_url/some_script.php

Remove the request_fulluri => 1 option, and $_SERVER['REQUEST_URI'] gets back to its "normal":
/some_script.php

Apparently, request_fulluri is useful when using some proxy servers.

In this case, there is no proper way to "detect" if this option was set or not, and you should probably use a combination of other $_SERVER[] elements (like REQUEST_SCHEME, SERVER_NAME and SERVER_PORT) to determine if this was the case.

One quick (and improvable) way to detect it would be to compare the start of the REQUEST_URI with REQUEST_SCHEME:

$scheme = $_SERVER['REQUEST_SCHEME'] . '://';
if (strcmp(substr($_SERVER['REQUEST_URI'], 0, strlen($scheme)), $scheme) === 0) {
// request_fulluri was set
}
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14
krinklemail at gmail dot com
11 years ago
If requests to your PHP script send a header "Content-Type" or/ "Content-Length" it will, contrary to regular HTTP headers, not appear in $_SERVER as $_SERVER['HTTP_CONTENT_TYPE']. PHP removes these (per CGI/1.1 specification[1]) from the HTTP_ match group.

They are still accessible, but only if the request was a POST request. When it is, it'll be available as:
$_SERVER['CONTENT_LENGTH']
$_SERVER['CONTENT_TYPE']

[1] https://www.ietf.org/rfc/rfc3875
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3
Daniels118
2 years ago
If you need to know the protocol (http or https) used by the client, then the $_SERVER['HTTPS'] variable may not actually report the truth if your server is behind a proxy or a load balancer (In fact the client could connect to the load balancer using https, and then the load balancer forward the request to the server using http).
If the proxy/load balancer is correctly configured it could send the original request protocol in a header, and you will find it in the $_SERVER[HTTP_X_FORWARDED_PROTO] variable.
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10
chris at ocproducts dot com
6 years ago
Guide to URL paths...

Data: $_SERVER['PHP_SELF']
Data type: String
Purpose: The URL path name of the current PHP file, including path-info (see $_SERVER['PATH_INFO']) and excluding URL query string. Includes leading slash.
Caveat: This is after URL rewrites (i.e. it's as seen by PHP, not necessarily the original call URL).
Works on web mode: Yes
Works on CLI mode: Tenuous (emulated to contain just the exact call path of the CLI script, with whatever exotic relative pathname you may call with, not made absolute and not normalised or pre-resolved)

Data: $_SERVER['SCRIPT_NAME']
Data type: String
Purpose: The URL path name of the current PHP file, excluding path-info and excluding URL query string. Includes leading slash.
Caveat: This is after URL rewrites (i.e. it's as seen by PHP, not necessarily the original call URL).
Caveat: Not set on all PHP environments, may need setting via preg_replace('#\.php/.*#', '.php', $_SERVER['PHP_SELF']).
Works on web mode: Yes
Works on CLI mode: Tenuous (emulated to contain just the exact call path of the CLI script, with whatever exotic relative pathname you may call with, not made absolute and not normalised or pre-resolved)

Data: $_SERVER['REDIRECT_URL']
Data type: String
Purpose: The URL path name of the current PHP file, path-info is N/A and excluding URL query string. Includes leading slash.
Caveat: This is before URL rewrites (i.e. it's as per the original call URL).
Caveat: Not set on all PHP environments, and definitely only ones with URL rewrites.
Works on web mode: Yes
Works on CLI mode: No

Data: $_SERVER['REQUEST_URI']
Data type: String
Purpose: The URL path name of the current PHP file, including path-info and including URL query string. Includes leading slash.
Caveat: This is before URL rewrites (i.e. it's as per the original call URL). *
*: I've seen at least one situation where this is not true (there was another $_SERVER variable to use instead supplied by the URL rewriter), but the author of the URL rewriter later fixed it so probably fair to dismiss this particular note.
Caveat: Not set on all PHP environments, may need setting via $_SERVER['REDIRECT_URL'] . '?' . http_build_query($_GET) [if $_SERVER['REDIRECT_URL'] is set, and imperfect as we don't know what GET parameters were originally passed vs which were injected in the URL rewrite] --otherwise-- $_SERVER['PHP_SELF'] . '?' . http_build_query($_GET).
Works on web mode: Yes
Works on CLI mode: No

Data: $_SERVER['PATH_INFO']
Data type: String
Purpose: Find the path-info, which is data after the .php filename in the URL call. It's a strange concept.
Caveat: Some environments may not support it, it is best avoided unless you have complete server control
Works on web mode: Yes
Works on CLI mode: No

Note that if something is not set it may be missing from $_SERVER, or it may be blank, so use PHP's 'empty' function for your test.
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10
Tonin
15 years ago
When using the $_SERVER['SERVER_NAME'] variable in an apache virtual host setup with a ServerAlias directive, be sure to check the UseCanonicalName apache directive. If it is On, this variable will always have the apache ServerName value. If it is Off, it will have the value given by the headers sent by the browser.

Depending on what you want to do the content of this variable, put in On or Off.
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7
Stefano (info at sarchittu dot org)
13 years ago
A way to get the absolute path of your page, independent from the site position (so works both on local machine and on server without setting anything) and from the server OS (works both on Unix systems and Windows systems).

The only parameter it requires is the folder in which you place this script
So, for istance, I'll place this into my SCRIPT folder, and I'll write SCRIPT word length in $conflen

<?php
$conflen
=strlen('SCRIPT');
$B=substr(__FILE__,0,strrpos(__FILE__,'/'));
$A=substr($_SERVER['DOCUMENT_ROOT'], strrpos($_SERVER['DOCUMENT_ROOT'], $_SERVER['PHP_SELF']));
$C=substr($B,strlen($A));
$posconf=strlen($C)-$conflen-1;
$D=substr($C,1,$posconf);
$host='http://'.$_SERVER['SERVER_NAME'].'/'.$D;
?>

$host will finally contain the absolute path.
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12
steve at sc-fa dot com
14 years ago
If you are serving from behind a proxy server, you will almost certainly save time by looking at what these $_SERVER variables do on your machine behind the proxy.

$_SERVER['HTTP_X_FORWARDED_FOR'] in place of $_SERVER['REMOTE_ADDR']

$_SERVER['HTTP_X_FORWARDED_HOST'] and
$_SERVER['HTTP_X_FORWARDED_SERVER'] in place of (at least in our case,) $_SERVER['SERVER_NAME']
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4
Mark Simon
4 years ago
So near, and yet so far …

$_SERVER has nearly everything you need to know about the current web page environment. Something which would have been handy is easy access to the protocol and the actual web root.

For the protocol, you may or may not have $_SERVER['HTTPS'] and it may or may not be empty. For the web root, $_SERVER['DOCUMENT_ROOT'] depends on the server configuration, and doesn’t work for virtual hosts.

For practical purposes, I normally include something like the following in my scripts:

<?php
// Web Root
// Usage: include("$root/includes/something.inc.php");
$root = $_SERVER['WEB_ROOT'] = str_replace($_SERVER['SCRIPT_NAME'],'',$_SERVER['SCRIPT_FILENAME']);

// Host & Protocol
// Usage: $url = "$protocol://$host/images/something.jpg";
$host = $_SERVER['HTTP_HOST'];
$protocol=$_SERVER['PROTOCOL'] = isset($_SERVER['HTTPS']) && !empty($_SERVER['HTTPS']) ? 'https' : 'http';
?>
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3
lemonostif at gmail dot com
4 years ago
PHP_SELF is a disgrace of a programmer's work. One of the most widespread PHP vulnerabilities since version 4 and the manual says nothing about the dangers. At least clarify that ITS VALUE CAN BE PROVIDED BY THE USER with capitals preferably if you want to make the internet a safer place...
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6
info at mtprod dot com
15 years ago
On Windows IIS 7 you must use $_SERVER['LOCAL_ADDR'] rather than $_SERVER['SERVER_ADDR'] to get the server's IP address.
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5
jarrod at squarecrow dot com
14 years ago
$_SERVER['DOCUMENT_ROOT'] is incredibly useful especially when working in your development environment. If you're working on large projects you'll likely be including a large number of files into your pages. For example:

<?php
//Defines constants to use for "include" URLS - helps keep our paths clean

define("REGISTRY_CLASSES", $_SERVER['DOCUMENT_ROOT']."/SOAP/classes/");
define("REGISTRY_CONTROLS", $_SERVER['DOCUMENT_ROOT']."/SOAP/controls/");

define("STRING_BUILDER", REGISTRY_CLASSES. "stringbuilder.php");
define("SESSION_MANAGER", REGISTRY_CLASSES. "sessionmanager.php");
define("STANDARD_CONTROLS", REGISTRY_CONTROLS."standardcontrols.php");
?>

In development environments, you're rarely working with your root folder, especially if you're running PHP locally on your box and using DOCUMENT_ROOT is a great way to maintain URL conformity. This will save you hours of work preparing your application for deployment from your box to a production server (not to mention save you the headache of include path failures).
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5
Tom
11 years ago
Be warned that most contents of the Server-Array (even $_SERVER['SERVER_NAME']) are provided by the client and can be manipulated. They can also be used for injections and thus MUST be checked and treated like any other user input.
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4
php at isnoop dot net
13 years ago
Use the apache SetEnv directive to set arbitrary $_SERVER variables in your vhost or apache config.

SetEnv varname "variable value"
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3
picov at e-link dot it
12 years ago
A simple function to detect if the current page address was rewritten by mod_rewrite:

<?php
public function urlWasRewritten() {
$realScriptName=$_SERVER['SCRIPT_NAME'];
$virtualScriptName=reset(explode("?", $_SERVER['REQUEST_URI']));
return !(
$realScriptName==$virtualScriptName);
}
?>
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1
centurianii at yahoo dot co dot uk
6 years ago
If you apply redirection in ALL your requests using commands at the Apache virtual host file like:
RewriteEngine On
RewriteCond "%{REQUEST_URI}" "!=/index.php"
RewriteRule "^/(.*)$" "index.php?$1" [NC,NE,L,QSA]
you should expect some deviations in your $_SERVER global.

Say, you send a url of: [hostname here]/a/b?x=1&y=2
which makes Apache to modify to: /index.php?/a/b?x=1&y=2

Now your $_SERVER global contains among others:
'REQUEST_URI' => '/a/b?x=1&y=2', it retains the initial url after the host
'QUERY_STRING' => 'a/b&x=1&y=2', notice how php replaces '?' with '&'
'SCRIPT_NAME' => '/index.php', as it was intended to be.

To test your $_SERVER global:
function serverArray(){
$arr = array();
foreach($_SERVER as $key=>$value)
$arr[] = '&nbsp;&nbsp;&nbsp;\'' . $key . '\' => \'' . (isset($value)? $value : '-') . '\'';
return @\sort($arr)? '$_SERVER = array(<br />' . implode($arr, ',<br />') . '<br />);' : false;
}
echo serverArray();
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4
chris
14 years ago
A table of everything in the $_SERVER array can be found near the bottom of the output of phpinfo();
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1
chris at ocproducts dot com
6 years ago
Guide to script parameters...

Data: $_GET
Data type: Array (map)
Purpose: Contains all GET parameters (i.e. a parsed URL query string).
Caveat: GET parameter names have to be compliant with PHP variable naming, e.g. dots are not allowed and get substituted.
Works on web mode: Yes
Works on CLI mode: No

Data: $_SERVER['QUERY_STRING']
Data type: String
Purpose: Gets an unparsed URL query string.
Caveat: Not set on all PHP environments, may need setting via http_build_query($_GET).
Works on web mode: Yes
Works on CLI mode: No

Data: $_SERVER['argv']
Data type: Array (list)
Purpose: Get CLI call parameters.
Works on web mode: Tenuous (just contains a single parameter, the query string)
Works on CLI mode: Yes
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silverquick at gmail dot com
15 years ago
I think the HTTPS element will only be present under Apache 2.x. It's not in the list of "special" variables here:
http://httpd.apache.org/docs/1.3/mod/mod_rewrite.html#RewriteCond
But it is here:
http://httpd.apache.org/docs/2.0/mod/mod_rewrite.html#rewritecond
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mirko dot steiner at slashdevslashnull dot de
14 years ago
<?php

// RFC 2616 compatible Accept Language Parser
// http://www.ietf.org/rfc/rfc2616.txt, 14.4 Accept-Language, Page 104
// Hypertext Transfer Protocol -- HTTP/1.1

foreach (explode(',', $_SERVER['HTTP_ACCEPT_LANGUAGE']) as $lang) {
$pattern = '/^(?P<primarytag>[a-zA-Z]{2,8})'.
'(?:-(?P<subtag>[a-zA-Z]{2,8}))?(?:(?:;q=)'.
'(?P<quantifier>\d\.\d))?$/';

$splits = array();

printf("Lang:,,%s''\n", $lang);
if (
preg_match($pattern, $lang, $splits)) {
print_r($splits);
} else {
echo
"\nno match\n";
}
}

?>

example output:

Google Chrome 3.0.195.27 Windows xp

Lang:,,de-DE''
Array
(
[0] => de-DE
[primarytag] => de
[1] => de
[subtag] => DE
[2] => DE
)
Lang:,,de;q=0.8''
Array
(
[0] => de;q=0.8
[primarytag] => de
[1] => de
[subtag] =>
[2] =>
[quantifier] => 0.8
[3] => 0.8
)
Lang:,,en-US;q=0.6''
Array
(
[0] => en-US;q=0.6
[primarytag] => en
[1] => en
[subtag] => US
[2] => US
[quantifier] => 0.6
[3] => 0.6
)
Lang:,,en;q=0.4''
Array
(
[0] => en;q=0.4
[primarytag] => en
[1] => en
[subtag] =>
[2] =>
[quantifier] => 0.4
[3] => 0.4
)
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pomat at live dot it
10 years ago
$_SERVER['DOCUMENT_ROOT'] may contain backslashes on windows systems, and of course it may or may not have a trailing slash (backslash).
I saw the following as an example of the proper way we're supposed to deal with this issue:

<?php
include(dirname($_SERVER['DOCUMENT_ROOT']) . DIRECTORY_SEPARATOR . 'file.php');
?>

Ok, the latter may be used to access a file inside the parent directory of the document root, but actually does not properly address the issue.
In the end, don't warry about. It should be safe to use forward slashes and append a trailing slash in all cases.
Let's say we have this:

<?php
$path
= 'subdir/file.php';
$result = $_SERVER['DOCUMENT_ROOT'] . '/' . $path;
?>

On linux $result might be something like
1) "/var/www/subdir/file.php"
2) "/var/www//subdir/file.php"
String 2 is parsed the same as string 1 (have a try with command 'cd').

On windows $result might be something like
1) "C:/apache/htdocs/subdir/file.php"
2) "C:/apache/htdocs//subdir/file.php"
3) "C:\apache\htdocs/subdir/file.php"
4) "C:\apache\htdocs\/subdir/file.php"
All those strings are parsed as "C:\apache\htdocs\subdir\file.php" (have a try with 'cd').
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pudding06 at gmail dot com
14 years ago
Here's a simple, quick but effective way to block unwanted external visitors to your local server:

<?php
// only local requests
if ($_SERVER['REMOTE_ADDR'] !== '127.0.0.1') die(header("Location: /"));
?>

This will direct all external traffic to your home page. Of course you could send a 404 or other custom error. Best practice is not to stay on the page with a custom error message as you acknowledge that the page does exist. That's why I redirect unwanted calls to (for example) phpmyadmin.
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sammyhacker at gmail dot com
2 years ago
To put it simply, $_SERVER contains all the environment variables.

CGI works by an HTTP application server filling in all the required environment variables and invoking the PHP process. And these environment variables are stored under $_SERVER.
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2
wbeaumo1 at gmail dot com
13 years ago
Don't forget $_SERVER['HTTP_COOKIE']. It contains the raw value of the 'Cookie' header sent by the user agent.
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lilJoshu
5 years ago
Remember,

Although $_SERVER["REQUEST_METHOD"] is initially built with GET, POST, PUT, HEAD in mind, a server can allow more.

This may be important if you're building a RESTful interfaces that will also use methods such as PATCH and DELETE.

Also important as a security risk as a possible point of injection. In the event of building something acting based on REQUEST_METHOD, it's recommended to put it in a switch statement.

<?php
switch ($_SERVER["REQUEST_METHOD"]){
case
"PUT":
foo_replace_data();
break;
case
"POST":
foo_add_data();
break;
case
"HEAD";
foo_set_that_cookie();
break;
case
"GET":
default:
foo_fetch_stuff()
break;
}

?>
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jit_chavan at yahoo dot com
10 years ago
searched $_SERVER["REDIRECT_URL"] for a while and noted that it is not mentioned in php documentation page itself. look like this is only generated by apache server(not others) and using $_SERVER["REQUEST_URI"] will be useful in some cases as mine.
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plugwash at p10link dot net
8 years ago
Be aware that it's a bad idea to access x-forwarded-for and similar headers through this array. The header names are mangled when populating the array and this mangling can introduce spoofing vulnerabilities.

See http://en.wikipedia.org/wiki/User:Brion_VIBBER/Cool_Cat_incident_report for details of a real world exploit of this.
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2962051004 at qq dot com
6 years ago
<?php
/*
Sometimes you will find that your website will not get the correct user IP after adding CDN, then this function will help you
*/
function real_ip()
{
$ip = $_SERVER['REMOTE_ADDR'];
if (isset(
$_SERVER['HTTP_X_FORWARDED_FOR']) && preg_match_all('#\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}#s', $_SERVER['HTTP_X_FORWARDED_FOR'], $matches)) {
foreach (
$matches[0] AS $xip) {
if (!
preg_match('#^(10|172\.16|192\.168)\.#', $xip)) {
$ip = $xip;
break;
}
}
} elseif (isset(
$_SERVER['HTTP_CLIENT_IP']) && preg_match('/^([0-9]{1,3}\.){3}[0-9]{1,3}$/', $_SERVER['HTTP_CLIENT_IP'])) {
$ip = $_SERVER['HTTP_CLIENT_IP'];
} elseif (isset(
$_SERVER['HTTP_CF_CONNECTING_IP']) && preg_match('/^([0-9]{1,3}\.){3}[0-9]{1,3}$/', $_SERVER['HTTP_CF_CONNECTING_IP'])) {
$ip = $_SERVER['HTTP_CF_CONNECTING_IP'];
} elseif (isset(
$_SERVER['HTTP_X_REAL_IP']) && preg_match('/^([0-9]{1,3}\.){3}[0-9]{1,3}$/', $_SERVER['HTTP_X_REAL_IP'])) {
$ip = $_SERVER['HTTP_X_REAL_IP'];
}
return
$ip;

}
echo
real_ip();

?>
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cupy at email dot cz
14 years ago
Tech note:
$_SERVER['argc'] and $_SERVER['argv'][] has some funny behaviour,
used from linux (bash) commandline, when called like
"php ./script_name.php 0x020B"
there is everything correct, but
"./script_name.php 0x020B"
is not correct - "0" is passed instead of "0x020B" as $_SERVER['argv'][1] - see the script below.
Looks like the parameter is not passed well from bash to PHP.
(but, inspected on the level of bash, 0x020B is understood well as $1)

try this example:

------------->8------------------
cat ./script_name.php
#! /usr/bin/php

if( $_SERVER['argc'] == 2)
{
// funny... we have to do this trick to pass e.g. 0x020B from parameters
// ignore this: "PHP Notice: Undefined offset: 2 in ..."
$EID = $_SERVER['argv'][1] + $_SERVER['argv'][2] + $_SERVER['argv'][3];
}
else
{ // default
$EID = 0x0210; // PPS failure
}
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Johan Winge
3 years ago
It should probably be noted that the value of $_SERVER['SERVER_PROTOCOL'] will never contain the substring "HTTPS". Assuming this is a common source of bugs and confusion. Instead, see $_SERVER['HTTPS'].
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DanielTahar
3 years ago
To expand a bit on the price you could pay for relying on 'HTTP_REFERER': several large news sites I read often have paywalls, with cookies in place so you can only read X articles before you must subscribe; if using Incognito, they count the number of times you accessed via the same IP; everything to get you to subscribe. However, in order to be appealing, any visit where the 'HTTP_REFERER' is Google News will give you the entire article. I'm sure it's a dilemma their webmasters have, but for now any time someone sends you a story on one of them, all you have to do is search for the title and click the result from Google News. Bottom line: never count on it.

PS (1): ofcourse i'm talking about a friend. I pay for content.
PS (2): after some debate, the RFC decided to keep 'HTTP_REFERER', although it's misspelled.
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kamil00110
7 months ago
This code can be used to help find somone that tries to dig throught the server files to find something.

.htaccess

ErrorDocument 404 /your.php
ErrorDocument 403 /your.php

<?php
//get time
$time = date("H:i:s d.m.y");
//get user address
$usr = $_SERVER['REMOTE_ADDR'];
//get entered url of the "visitor"
$url = $_SERVER['REQUEST_URI'];
//get your servers address
$ip = $_SERVER['SERVER_ADDR'];
//put toogether
$sus = "[".$time."] ".$usr." ".$ip.$url.PHP_EOL;
//write an log file
file_put_contents("susip.txt", $sus, FILE_APPEND);
?>
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Florin C
10 months ago
<?php
//Working example tested with success in Debian Linux with Apache 2.4

$protocol=$_SERVER['PROTOCOL'] = isset($_SERVER['HTTPS']) && !empty($_SERVER['HTTPS']) ? 'https' : 'http'; //thanks to Mark Simon @ https://www.php.net/manual/en/reserved.variables.server.php
$doc_root = $_SERVER['DOCUMENT_ROOT']; // e.g. /var/www/webabc/web/
$module_path = dirname(__FILE__); // e.g. /var/www/webabc/web/modules/verstion152/
$host = $_SERVER['HTTP_HOST']; // e.g. 192.168.1.4

$online_path = $protocol .'://'. $host . '/' . str_replace($doc_root, '', $module_path);

echo
"The online path is: " . $online_path;
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