Home > Articles > Programming > ASP .NET

  • Print
  • + Share This
This chapter is from the book

This chapter is from the book

ServerVariables

Another collection provided by the Request object is ServerVariables. Any HTTP header that is sent by a client browser is available in this collection with code such as the following:

Dim strValueData as String
strValueData = Request.ServerVariable( "HeaderType" )

The standard HTTP headers are automatically defined as members of the ServerVariables collection. For example, when form data is sent to the server, the method by which it was sent can be determined from

Dim strRequestMethod as String
strRequestMethod = Request.ServerVariables( "REQUEST_METHOD" )
' Either GET or POST

You can also use the QUERY_STRING header to obtain the original unadulterated query string that was passed to the server from the browser. A great many headers are available in this collection; and some have been processed and presented in collections such a QueryString and others have not. Table 3.3 has a list of the HTTP header types that are available.

Table 3.3 The HTTP Header Types

Type

Description

ALL_HTTP

All HTTP headers sent by the client.

ALL_RAW

Retrieves all headers in their raw form. The difference between ALL_RAW and ALL_HTTP is that ALL_HTTP places an HTTP_ prefix before the header name and the header name is always capitalized. In ALL_RAW the header name and values appear as they were sent by the client.

APPL_MD_PATH

Retrieves the metabase path for the (WAM) Application for the ISAPI DLL.

APPL_PHYSICAL_PATH

Retrieves the physical path corresponding to the metabase path. IIS converts the APPL_MD_PATH to the physical (directory) path to return this value.

AUTH_PASSWORD

The value entered in the client's authentication dialog box. This variable is available only if Basic authentication is used.

AUTH_TYPE

The authentication method that the server uses to validate users when they attempt to access a protected script.

AUTH_USER

Raw authenticated username.

CERT_COOKIE

Unique ID for client certificate. Returned as a string. Can be used as a signature for the whole client certificate.

CERT_FLAGS

If the client certificate is present, bit0 is set to 1. If the Certifying Authority of the client certificate is invalid (not in the list of recognized CA on the server), bit1 is set to 1.

CERT_ISSUER

Issuer field of the client certificate (O=MS, OU=IAS, CN=user name, C=USA).

CERT_KEYSIZE

Number of bits in Secure Sockets Layer connection key size. For example, 128.

CERT_SECRETKEYSIZE

Number of bits in server certificate private key. For example, 1024.

CERT_SERIALNUMBER

Serial number field of the client certificate.

CERT_SERVER_ISSUER

Issuer field of the server certificate.

CERT_SERVER_SUBJECT

Subject field of the server certificate.

CERT_SUBJECT

Subject field of the client certificate.

CONTENT_LENGTH

The length of the content as given by the client.

CONTENT_TYPE

The data type of the content. Used with queries that have attached information, such as the HTTP queries GET, POST, and PUT.

GATEWAY_INTERFACE

The revision of the CGI specification used by the server. The format is CGI/revision.

HTTP_<HeaderName>

The value stored in the header HeaderName. Any header other than those listed in this table must be prefixed by HTTP_ for the ServerVariables collection to retrieve its value.

HTTP_ACCEPT

Returns the value of the Accept header.

HTTP_ACCEPT_LANGUAGE

Returns a string describing the language to use for displaying content.

HTTP_USER_AGENT

Returns a string describing the browser that sent the request.

HTTP_COOKIE

Returns the cookie string that was included with the request.

HTTP_REFERER

Returns a string containing the URL of the page that referred the request to the current page, but does not include redirect requests.

HTTPS

Returns ON if the request came in through a secure channel (SSL) or it returns OFF if the request is for a non-secure channel.

HTTPS_KEYSIZE

Number of bits in Secure Sockets Layer connection key size. For example, 128.

HTTPS_SECRETKEYSIZE

Number of bits in server certificate private key. For example, 1024.

HTTPS_SERVER_ISSUER

Issuer field of the server certificate.

HTTPS_SERVER_SUBJECT

Subject field of the server certificate.

INSTANCE_ID

The ID for the IIS instance in textual format. If the instance ID is 1, it appears as a string. You can use this variable to retrieve the ID of the Web server instance (in the metabase) to which the request belongs.

INSTANCE_META_PATH

The metabase path for the instance of IIS that responds to the request.

LOCAL_ADDR

Returns the server address on which the request came in. This is important on multi-homed machines where multiple IP addresses can be bound to a machine and you want to find out which address the request used.

LOGON_USER

The Windows NT account that the user is logged into.

PATH_INFO

Extra path information as given by the client. You can access a script by using its virtual path and the PATH_INFO server variable. If this information comes from a URL, the server decodes it before passing it to the CGI script.

PATH_TRANSLATED

A translated version of PATH_INFO that takes the path and performs any necessary virtual-to-physical mapping.

QUERY_STRING

Query information stored in the string following the question mark (?) in the HTTP request.

REMOTE_ADDR

The IP address of the remote host making the request.

REMOTE_HOST

The name of the host making the request. If the server does not have this information, it sets REMOTE_ADDR and leaves this header empty.

REMOTE_USER

Unmapped username string sent in by the user. This is the name that is really sent by the user as opposed to the ones that are modified by any authentication filter installed on the server.

REQUEST_METHOD

The method used to make the request. For HTTP, this is GET, HEAD, POST, and so on.

SCRIPT_NAME

A virtual path to the script being executed. This is used for self-referencing URLs.

SERVER_NAME

The server's host name, DNS alias, or IP address as it would appear in self-referencing URLs.

SERVER_PORT

The port number to which the request was sent.

SERVER_PORT_SECURE

A string that contains either 0 or 1. If the request is being handled on the secure port, then this is 1. Otherwise, it is 0.

SERVER_PROTOCOL

The name and revision of the request information protocol. The format is protocol/revision.

SERVER_SOFTWARE

The name and version of the server software that answers the request and runs the gateway. The format is name/version.

URL

Gives the base portion of the URL.


It's easy to use the Request.ServerVariables() method to find out some interesting information. The following code retrieves a list of helpful items and displays them in the HTML document:

REMOTE_ADDR: <%=Request.ServerVariables("REMOTE_ADDR")%><br>
REMOTE_HOST: <%=Request.ServerVariables("REMOTE_HOST")%><br>
REMOTE_USER: <%=Request.ServerVariables("REMOTE_USER")%><br>
REQUEST_METHOD: <%=Request.ServerVariables("REQUEST_METHOD")%><br>
SERVER_NAME: <%=Request.ServerVariables("SERVER_NAME")%><br>
SERVER_PORT: <%=Request.ServerVariables("SERVER_PORT")%><br>
SERVER_PROTOCOL: <%=Request.ServerVariables("SERVER_PROTOCOL")%><br>
SERVER_SOFTWARE: <%=Request.ServerVariables("SERVER_SOFTWARE")%><br>
URL: <%=Request.ServerVariables("URL")%><br>

NOTE

This code is part of the page that you can find at http://www.UsingASP.net, selecting Chapter Examples, Chapter 3, then ServerVariables. You can see the rendered page in Figure 3.15.

Figure 3.15 Some server variables are shown here in the browser window.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020