description

# HttpHeaders class abstract interface

Headers for HTTP requests and responses.

In some situations, headers are immutable:

- HttpRequest and HttpClientResponse always have immutable headers.

- HttpResponse and HttpClientRequest have immutable headers from the moment the body is written to.

In these situations, the mutating methods throw exceptions.

For all operations on HTTP headers the header name is case-insensitive.

To set the value of a header use the `set()` method:

    request.headers.set(HttpHeaders.cacheControlHeader,
                        'max-age=3600, must-revalidate');

To retrieve the value of a header use the `value()` method:

    print(request.headers.value(HttpHeaders.userAgentHeader));

An `HttpHeaders` object holds a list of values for each name as the standard allows. In most cases a name holds only a single value, The most common mode of operation is to use `set()` for setting a value, and `value()` for retrieving a value.

## Properties

chunkedTransferEncoding ↔ bool
  Whether the connection uses chunked transfer encoding.
  getter/setter pair
contentLength ↔ int
  The value of the contentLengthHeader header, if any.
  getter/setter pair
contentType ↔ ContentType?
  The ContentType of the contentTypeHeader header, if any.
  getter/setter pair
date ↔ DateTime?
  The date specified by the dateHeader header, if any.
  getter/setter pair
expires ↔ DateTime?
  The date and time specified by the expiresHeader header, if any.
  getter/setter pair
hashCode → int
  The hash code for this object.
  no setter inherited
host ↔ String?
  The value of the hostHeader header, if any.
  getter/setter pair
ifModifiedSince ↔ DateTime?
  The date and time specified by the ifModifiedSinceHeader header, if any.
  getter/setter pair
persistentConnection ↔ bool
  Whether the connection is persistent (keep-alive).
  getter/setter pair
port ↔ int?
  The value of the port part of the hostHeader header, if any.
  getter/setter pair
runtimeType → Type
  A representation of the runtime type of the object.
  no setter inherited

## Methods

add(String name, Object value, {bool preserveHeaderCase = false}) → void
  Adds a header value.
clear() → void
  Removes all headers.
forEach(void action(String name, List<String> values)) → void
  Performs the `action` on each header.
noFolding(String name) → void
  Disables folding for the header named `name` when sending the HTTP header.
noSuchMethod(Invocation invocation) → dynamic
  Invoked when a nonexistent method or property is accessed.
  inherited
remove(String name, Object value) → void
  Removes a specific value for a header name.
removeAll(String name) → void
  Removes all values for the specified header name.
set(String name, Object value, {bool preserveHeaderCase = false}) → void
  Sets the header `name` to `value`.
toString() → String
  A string representation of this object.
  inherited
value(String name) → String?
  Convenience method for the value for a single valued header.

## Operators

operator ==(Object other) → bool
  The equality operator.
  inherited
operator [](String name) → List<String>?
  The values for the header named `name`.

## Constants

acceptCharsetHeader → const String
acceptEncodingHeader → const String
acceptHeader → const String
acceptLanguageHeader → const String
acceptRangesHeader → const String
accessControlAllowCredentialsHeader → const String
accessControlAllowHeadersHeader → const String
accessControlAllowMethodsHeader → const String
accessControlAllowOriginHeader → const String
accessControlExposeHeadersHeader → const String
accessControlMaxAgeHeader → const String
accessControlRequestHeadersHeader → const String
accessControlRequestMethodHeader → const String
ageHeader → const String
allowHeader → const String
authorizationHeader → const String
cacheControlHeader → const String
connectionHeader → const String
contentDisposition → const String
contentEncodingHeader → const String
contentLanguageHeader → const String
contentLengthHeader → const String
contentLocationHeader → const String
contentMD5Header → const String
contentRangeHeader → const String
contentTypeHeader → const String
cookieHeader → const String
dateHeader → const String
entityHeaders → const List<String>
etagHeader → const String
expectHeader → const String
expiresHeader → const String
fromHeader → const String
generalHeaders → const List<String>
hostHeader → const String
ifMatchHeader → const String
ifModifiedSinceHeader → const String
ifNoneMatchHeader → const String
ifRangeHeader → const String
ifUnmodifiedSinceHeader → const String
lastModifiedHeader → const String
locationHeader → const String
maxForwardsHeader → const String
pragmaHeader → const String
proxyAuthenticateHeader → const String
proxyAuthorizationHeader → const String
rangeHeader → const String
refererHeader → const String
requestHeaders → const List<String>
responseHeaders → const List<String>
retryAfterHeader → const String
serverHeader → const String
setCookieHeader → const String
teHeader → const String
trailerHeader → const String
transferEncodingHeader → const String
upgradeHeader → const String
userAgentHeader → const String
varyHeader → const String
viaHeader → const String
warningHeader → const String
wwwAuthenticateHeader → const String