Client browser HTTP header data using Request object in ASP

When ever browser send request for a page to the server, along with the URL some more information also the browser provides to the server. This additional header information can be collected at the server end. Same way while sending back the content of the page requested by the browser the server sends some more header information back to it. All these header information can be collected at different ends and used in our scripts. We can access these HTTP header information's and accordingly modify the content at server end. For example we need to display a different pages for different languages. By reading the header information on HTTP_USER_AGENT we can find out what is the language setting of the client browser and then redirect to that particular language page of the user.

To get the http headers we will be using ServerVariables collection of Request object in ASP. To display the value of a particular header we have to use the header name like this .

<%= Request.ServerVariables("HTTP_USER_AGENT")%>

The above line will display the client browser details, with language settings etc. Here is one sample output for Firefox browser at client side.

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.8) Gecko/20061025 Firefox/1.5.0.8

We can display all the header information in one go without calling one by one by using its name. Here we have to use ALL_RAW

<%= Request.ServerVariables("ALL_RAW")%>

If we need formatted output with the list of headers (name ) then we have to use ALL_HTTP

<%= Request.ServerVariables("ALL_HTTP")%>

We can display all the name value pairs for all the header information like this

Dim var 
For Each var in Request.ServerVariables 
 Response.Write "<B>" & var & "</B>:" 
 Response.Write  Request.ServerVariables(var) 
Response.Write "<br>"

Next

The above code will display all header names and its values one by one. ( This output is on my laptop which runs IIS on WinXP so server address is localhost or 127.0.0.1 )

ALL_HTTP :

HTTP_ACCEPT:*/* 
  
HTTP_ACCEPT_LANGUAGE:en-us 
  
HTTP_CONNECTION:Keep-Alive 
  
HTTP_HOST:127.0.0.1 
  
HTTP_REFERER:https://127.0.0.1/a/request/ 
  
HTTP_USER_AGENT:Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1;
 Trident/4.0; GTB6.6; InfoPath.2; .NET CLR 1.1.4322;
 .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729) 
  
HTTP_COOKIE:__utmc=96992031; ASPSESSIONIDAQSACAQC=FHOPPKJCEMKILAHMPECCIAJJ;
 __utma=96992031.1294834349.1272246700.1286419100.1286425811.117;
 __utmz=96992031.1272246700.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utmb=96992031 
  
HTTP_ACCEPT_ENCODING:gzip, deflate

ALL_RAW :

Accept: */* 
  
Accept-Language: en-us 
  
Connection: Keep-Alive 
  
Host: 127.0.0.1 
  
Referer: https://127.0.0.1/a/request/ 
  
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1;
 Trident/4.0; GTB6.6; InfoPath.2; .NET CLR 1.1.4322;
 .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729) 
  
Cookie: __utmc=96992031; ASPSESSIONIDAQSACAQC=FHOPPKJCEMKILAHMPECCIAJJ;
 __utma=96992031.1294834349.1272246700.1286419100.1286425811.117;
 __utmz=96992031.1272246700.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utmb=96992031 
  
Accept-Encoding: gzip, deflate

APPL_MD_PATH	/LM/W3SVC/1/ROOT
APPL_PHYSICAL_PATH	I:\FL\
AUTH_PASSWORD
AUTH_TYPE
AUTH_USER
CERT_COOKIE
CERT_FLAGS
CERT_ISSUER
CERT_KEYSIZE
CERT_SECRETKEYSIZE
CERT_SERIALNUMBER
CERT_SERVER_ISSUER
CERT_SERVER_SUBJECT
CERT_SUBJECT
CONTENT_LENGTH	0
CONTENT_TYPE
GATEWAY_INTERFACE	CGI/1.1
HTTPS	off
HTTPS_KEYSIZE
HTTPS_SECRETKEYSIZE
HTTPS_SERVER_ISSUER
HTTPS_SERVER_SUBJECT
INSTANCE_ID	1
INSTANCE_META_PATH	/LM/W3SVC/1
LOCAL_ADDR	127.0.0.1
LOGON_USER
PATH_INFO	/a/request/header.asp
PATH_TRANSLATED	I:\FL\a\ request\header.asp
QUERY_STRING
REMOTE_ADDR	127.0.0.1
REMOTE_HOST	127.0.0.1
REMOTE_USER
REQUEST_METHOD	GET
SCRIPT_NAME	/a/request/header.asp
SERVER_NAME	127.0.0.1
SERVER_PORT	80
SERVER_PORT_SECURE	0
SERVER_PROTOCOL	HTTP/1.1
SERVER_SOFTWARE	Microsoft-IIS/5.1
URL	/a/request/header.asp
HTTP_ACCEPT	/
HTTP_ACCEPT_LANGUAGE	en-us
HTTP_CONNECTION	Keep-Alive
HTTP_HOST	127.0.0.1
HTTP_REFERER	https://127.0.0.1/a/ request/
HTTP_ACCEPT_ENCODING	gzip, deflate

HTTP_USER_AGENT:

Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; 
Trident/4.0; GTB6.6; InfoPath.2; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152;
 .NET CLR 3.5.30729)

HTTP_COOKIE

__utmc=96992031;
 ASPSESSIONIDAQSACAQC=FHOPPKJCEMKILAHMPECCIAJJ; 
__utma=96992031.1294834349.1272246700.1286419100.1286425811.117;
 __utmz=96992031.1272246700.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none);
 __utmb=96992031

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Getting all the header data of browser by using Request object ServerVariable in ASP