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HTTP_HEADER_ID enumeration (http.h)

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The HTTP_HEADER_ID enumeration type lists known headers for HTTP requests and responses, and associates an array index with each such header. It is used to size and access the KnownHeaders array members of the HTTP_REQUEST_HEADERS and HTTP_RESPONSE_HEADERS structures.

Syntax

typedef enum _HTTP_HEADER_ID {
  HttpHeaderCacheControl = 0,
  HttpHeaderConnection = 1,
  HttpHeaderDate = 2,
  HttpHeaderKeepAlive = 3,
  HttpHeaderPragma = 4,
  HttpHeaderTrailer = 5,
  HttpHeaderTransferEncoding = 6,
  HttpHeaderUpgrade = 7,
  HttpHeaderVia = 8,
  HttpHeaderWarning = 9,
  HttpHeaderAllow = 10,
  HttpHeaderContentLength = 11,
  HttpHeaderContentType = 12,
  HttpHeaderContentEncoding = 13,
  HttpHeaderContentLanguage = 14,
  HttpHeaderContentLocation = 15,
  HttpHeaderContentMd5 = 16,
  HttpHeaderContentRange = 17,
  HttpHeaderExpires = 18,
  HttpHeaderLastModified = 19,
  HttpHeaderAccept = 20,
  HttpHeaderAcceptCharset = 21,
  HttpHeaderAcceptEncoding = 22,
  HttpHeaderAcceptLanguage = 23,
  HttpHeaderAuthorization = 24,
  HttpHeaderCookie = 25,
  HttpHeaderExpect = 26,
  HttpHeaderFrom = 27,
  HttpHeaderHost = 28,
  HttpHeaderIfMatch = 29,
  HttpHeaderIfModifiedSince = 30,
  HttpHeaderIfNoneMatch = 31,
  HttpHeaderIfRange = 32,
  HttpHeaderIfUnmodifiedSince = 33,
  HttpHeaderMaxForwards = 34,
  HttpHeaderProxyAuthorization = 35,
  HttpHeaderReferer = 36,
  HttpHeaderRange = 37,
  HttpHeaderTe = 38,
  HttpHeaderTranslate = 39,
  HttpHeaderUserAgent = 40,
  HttpHeaderRequestMaximum = 41,
  HttpHeaderAcceptRanges = 20,
  HttpHeaderAge = 21,
  HttpHeaderEtag = 22,
  HttpHeaderLocation = 23,
  HttpHeaderProxyAuthenticate = 24,
  HttpHeaderRetryAfter = 25,
  HttpHeaderServer = 26,
  HttpHeaderSetCookie = 27,
  HttpHeaderVary = 28,
  HttpHeaderWwwAuthenticate = 29,
  HttpHeaderResponseMaximum = 30,
  HttpHeaderMaximum = 41
} HTTP_HEADER_ID, *PHTTP_HEADER_ID;

Constants

 
HttpHeaderCacheControl
Value: 0
Used to specify caching behavior along the request or response chain, overriding the default caching algorithm.
HttpHeaderConnection
Value: 1
Allows the sender to specify options that are desired for that particular connection. These are used for a single connection only and must not be communicated by proxies over further connections.
HttpHeaderDate
Value: 2
The Date is a general header field that indicates the time that the request or response was sent.
HttpHeaderKeepAlive
Value: 3
Based on the keepalive XML element (see RFC 2518, section 12.12.1, page 66); a list of URIs included in the KeepAlive
header must be "live" after they are copied
(moved) to the destination.
HttpHeaderPragma
Value: 4
Used to include optional, implementation-specific directives that might apply to any recipient along the request/response chain.
HttpHeaderTrailer
Value: 5
Indicates that specified header fields are present in the trailer of a message encoded with chunked transfer-coding.
HttpHeaderTransferEncoding
Value: 6
Indicates what, if any, transformations have been applied to the message body in transit.
HttpHeaderUpgrade
Value: 7
Allows the client to specify one or more other communication protocols it would prefer to use if the server can comply.
HttpHeaderVia
Value: 8
The Via header field indicates the path taken by the request.
HttpHeaderWarning
Value: 9
This is a response header that contains the 3-digit warn code along with the reason phrase.
HttpHeaderAllow
Value: 10
Lists the set of methods supported by the resource identified by the Request-URI.
HttpHeaderContentLength
Value: 11
The size of the message body in decimal bytes.
HttpHeaderContentType
Value: 12
The media type of the message body.
HttpHeaderContentEncoding
Value: 13
The encoding scheme for the message body.
HttpHeaderContentLanguage
Value: 14
Provides the natural language of the intended audience.
HttpHeaderContentLocation
Value: 15
Location of the resource for the entity enclosed in the message when that entity is accessible from a location separate from the requested resource's URI.
HttpHeaderContentMd5
Value: 16
An MD5 digest of the entity-body used to provide end-to-end message integrity check (MIC) of the entity-body.
HttpHeaderContentRange
Value: 17
The content range header is sent with a partial entity body to specify where in the full entity body the partial body should be applied.
HttpHeaderExpires
Value: 18
The date and time after which the message content expires.
HttpHeaderLastModified
Value: 19
Indicates the date and time at which the origin server believes the variant was last modified.
HttpHeaderAccept
Value: 20
Used with the INVITE, OPTIONS, and REGISTER methods to indicate what media types are acceptable in the response.
HttpHeaderAcceptCharset
Value: 21
Indicates the character sets that are acceptable for the response.
HttpHeaderAcceptEncoding
Value: 22
The content encodings that are acceptable in the response.
HttpHeaderAcceptLanguage
Value: 23
Used by the client to indicate to the server which language it would prefer to receive reason phrases, session descriptions, or status responses.
HttpHeaderAuthorization
Value: 24
The user-agent can authenticate itself with a server by sending the Authorization request header field with the request. The field contains the credentials for the domain that the user is requesting.
HttpHeaderCookie
Value: 25
The cookie request header contains data used to maintain client state with the server. Cookie data is obtained from a response sent with HttpHeaderSetCookie.
HttpHeaderExpect
Value: 26
Indicates the specific server behaviors that are required by the client.
HttpHeaderFrom
Value: 27
The From header field specifies the initiator of the SIP request or response message.
HttpHeaderHost
Value: 28
Specifies the Internet host and port number of the requested resource. This is obtained from the original URI given by the user or referring resource.
HttpHeaderIfMatch
Value: 29
The If-Match request header field is used with a method to make it conditional. A client that has one or more entities previously obtained from the resource can verify that one of those entities is current by including a list of their associated entity tags in the If-Match header field.
HttpHeaderIfModifiedSince
Value: 30
The If-Modified-Since request header field is used with a method to make it conditional. If the requested variant has not been modified since the time specified in this field, an entity is not returned from the server; instead, a 304 (not modified) response is returned without any message-body.
HttpHeaderIfNoneMatch
Value: 31
The If-None-Match request-header field is used with a method to make
it conditional. When a client has obtained one or more entities from a resource, it can verify that none of those entities is
current by including a list of their associated entity tags in the
If-None-Match header field. The purpose of this feature is to allow
efficient updates of cached information with a minimum amount of
transaction overhead, and to prevent a method such as PUT
from inadvertently modifying an existing resource when the client
believes that the resource does not exist.
HttpHeaderIfRange
Value: 32
If a client has a partial copy of an entity in its cache, and wishes
to obtain an up-to-date copy of the entire entity, it
can use the If-Range header. Informally, its meaning is, "if the entity is unchanged, send
me the part(s) I am missing; otherwise, send me the entire new
entity."
HttpHeaderIfUnmodifiedSince
Value: 33
The If-Unmodified-Since request-header field is used with a method to
make it conditional. If the requested resource has not been modified
since the time specified in this field, the server performs the
requested operation as if the If-Unmodified-Since header were not
present, but

if the requested resource has been modified,
the server returns
a 412 error (Precondition Failed).
HttpHeaderMaxForwards
Value: 34
The maximum number of proxies or gateways that can forward the request.
HttpHeaderProxyAuthorization
Value: 35
This header field is used by the client to identify itself with a proxy.
HttpHeaderReferer
Value: 36
Allows the client to specify, for the server's benefit, the address (URI) of the resource from which the Request-URI was obtained.
HttpHeaderRange
Value: 37
Allows a client to request a part of an entity instead of the whole.
HttpHeaderTe
Value: 38
This header field contains the recipient of the SIP request or response message.
HttpHeaderTranslate
Value: 39
Allows the client to specify whether it wants the source representation or programmatic interpretation of the requested content.
HttpHeaderUserAgent
Value: 40
Indicates what extension transfer-codings the client accepts in the response and whether or not the client accepts trailer fields in a chunked transfer-coding.
HttpHeaderRequestMaximum
Value: 41
Not a value that actually designates a header; instead, it is used to count the enumerated Request headers.
HttpHeaderAcceptRanges
Value: 20
Allows the server to indicate its acceptance of range requests for a resource.
HttpHeaderAge
Value: 21
Conveys the sender's estimate of the amount of time since the response (or its revalidation) was generated at the origin server.
HttpHeaderEtag
Value: 22
Provides the current value of the entity tag for the requested variant.
HttpHeaderLocation
Value: 23
Used to redirect the recipient to a location other than the Request-URI for completion of the request or identification of a new resource.
HttpHeaderProxyAuthenticate
Value: 24
The response field that must be included as a part of the 407 response. The field includes the authentication scheme and parameters that apply to the proxy for this Request-URI.
HttpHeaderRetryAfter
Value: 25
The length of time that the service is expected to be unavailable to the requesting client.
HttpHeaderServer
Value: 26
This is a response header field that contains information about the server that is handling the request.
HttpHeaderSetCookie
Value: 27
The set-cookie response header contains data used to maintain client state in future requests sent with HttpHeaderCookie.
HttpHeaderVary
Value: 28
Indicates the set of request header fields that fully determines, while the response is fresh, whether a cache is permitted to use the response to reply to a subsequent request without revalidation.
HttpHeaderWwwAuthenticate
Value: 29
The WWW_Authenticate header field contains the authentication schemes and parameters applicable to the Request-URI.
HttpHeaderResponseMaximum
Value: 30
Not a value that actually designates a header; instead, it is used to count the enumerated Response headers.
HttpHeaderMaximum
Value: 41
Not a value that actually designates a header; instead, it is used to count all the enumerated headers.

Requirements

Requirement Value
Minimum supported client Windows Vista, Windows XP with SP2 [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Header http.h

See also

HTTP_REQUEST_HEADERS

HTTP_RESPONSE_HEADERS