ContentType abstract interface

abstract interface class ContentType implements HeaderValue

A MIME/IANA media type used as the value of the HttpHeaders.contentTypeHeader header.

A ContentType is immutable.

Implemented types

• HeaderValue

Constructors

ContentType() factory

factory ContentType(
  String primaryType,
  String subType, {
  String? charset,
  Map<String, String?> parameters = const {},
})

Creates a new content type object setting the primary type and sub type. The charset and additional parameters can also be set using charset and parameters. If charset is passed and parameters contains charset as well the passed charset will override the value in parameters. Keys passed in parameters will be converted to lower case. The charset entry, whether passed as charset or in parameters, will have its value converted to lower-case.

Implementation

factory ContentType(
  String primaryType,
  String subType, {
  String? charset,
  Map<String, String?> parameters = const {},
}) {
  return _ContentType(primaryType, subType, charset, parameters);
}

Properties

charset no setter

String? get charset

Gets the character set, if any.

For the full content type text/html;charset=utf-8, the charset value is the string utf-8.

Implementation

String? get charset;

hashCode no setter inherited

int get hashCode

The hash code for this object.

A hash code is a single integer which represents the state of the object that affects operator == comparisons.

All objects have hash codes. The default hash code implemented by Object represents only the identity of the object, the same way as the default operator == implementation only considers objects equal if they are identical (see identityHashCode).

If operator == is overridden to use the object state instead, the hash code must also be changed to represent that state, otherwise the object cannot be used in hash based data structures like the default Set and Map implementations.

Hash codes must be the same for objects that are equal to each other according to operator ==. The hash code of an object should only change if the object changes in a way that affects equality. There are no further requirements for the hash codes. They need not be consistent between executions of the same program and there are no distribution guarantees.

Objects that are not equal are allowed to have the same hash code. It is even technically allowed that all instances have the same hash code, but if clashes happen too often, it may reduce the efficiency of hash-based data structures like HashSet or HashMap.

If a subclass overrides hashCode, it should override the operator == operator as well to maintain consistency.

Inherited from Object.

Implementation

external int get hashCode;

mimeType no setter

String get mimeType

Gets the MIME type and subtype, without any parameters.

For the full content type text/html;charset=utf-8, the mimeType value is the string text/html.

Implementation

String get mimeType;

parameters no setter inherited

Map<String, String?> get parameters

A map of parameters.

This map cannot be modified.

Inherited from HeaderValue.

Implementation

Map<String, String?> get parameters;

primaryType no setter

String get primaryType

Gets the primary type.

For the full content type text/html;charset=utf-8, the primaryType value is the string text.

Implementation

String get primaryType;

runtimeType no setter inherited

Type get runtimeType

A representation of the runtime type of the object.

Inherited from Object.

Implementation

external Type get runtimeType;

subType no setter

String get subType

Gets the subtype.

For the full content type text/html;charset=utf-8, the subType value is the string html. May be the empty string.

Implementation

String get subType;

value no setter inherited

String get value

The value of the header.

Inherited from HeaderValue.

Implementation

String get value;

Methods

noSuchMethod() inherited

dynamic noSuchMethod(Invocation invocation)

Invoked when a nonexistent method or property is accessed.

A dynamic member invocation can attempt to call a member which doesn't exist on the receiving object. Example:

dynamic object = 1;
object.add(42); // Statically allowed, run-time error

This invalid code will invoke the noSuchMethod method of the integer 1 with an Invocation representing the .add(42) call and arguments (which then throws).

Classes can override noSuchMethod to provide custom behavior for such invalid dynamic invocations.

A class with a non-default noSuchMethod invocation can also omit implementations for members of its interface. Example:

class MockList<T> implements List<T> {
  noSuchMethod(Invocation invocation) {
    log(invocation);
    super.noSuchMethod(invocation); // Will throw.
  }
}
void main() {
  MockList().add(42);
}

This code has no compile-time warnings or errors even though the MockList class has no concrete implementation of any of the List interface methods. Calls to List methods are forwarded to noSuchMethod, so this code will log an invocation similar to Invocation.method(#add, [42]) and then throw.

If a value is returned from noSuchMethod, it becomes the result of the original invocation. If the value is not of a type that can be returned by the original invocation, a type error occurs at the invocation.

The default behavior is to throw a NoSuchMethodError.

Inherited from Object.

Implementation

@pragma("vm:entry-point")
@pragma("wasm:entry-point")
external dynamic noSuchMethod(Invocation invocation);

toString() inherited

String toString()

A string representation of this object.

Some classes have a default textual representation, often paired with a static parse function (like int.parse). These classes will provide the textual representation as their string representation.

Other classes have no meaningful textual representation that a program will care about. Such classes will typically override toString to provide useful information when inspecting the object, mainly for debugging or logging.

Inherited from Object.

Implementation

external String toString();

Operators

operator ==() inherited

bool operator ==(Object other)

The equality operator.

The default behavior for all Objects is to return true if and only if this object and other are the same object.

Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:

• Total: It must return a boolean for all arguments. It should never throw.

• Reflexive: For all objects o, o == o must be true.

• Symmetric: For all objects o1 and o2, o1 == o2 and o2 == o1 must either both be true, or both be false.

• Transitive: For all objects o1, o2, and o3, if o1 == o2 and o2 == o3 are true, then o1 == o3 must be true.

The method should also be consistent over time, so whether two objects are equal should only change if at least one of the objects was modified.

If a subclass overrides the equality operator, it should override the hashCode method as well to maintain consistency.

Inherited from Object.

Implementation

external bool operator ==(Object other);

Static Properties

binary final

final ContentType binary

Content type for binary data.

application/octet-stream

Implementation

static final binary = ContentType("application", "octet-stream");

html final

final ContentType html

Content type for HTML using UTF-8 encoding.

text/html; charset=utf-8

Implementation

static final html = ContentType("text", "html", charset: "utf-8");

json final

final ContentType json

Content type for JSON using UTF-8 encoding.

application/json; charset=utf-8

Implementation

static final json = ContentType("application", "json", charset: "utf-8");

text final

final ContentType text

Content type for plain text using UTF-8 encoding.

text/plain; charset=utf-8

Implementation

static final text = ContentType("text", "plain", charset: "utf-8");

Static Methods

parse() override

ContentType parse(String value)

Creates a new content type object from parsing a Content-Type header value. As primary type, sub type and parameter names and values are not case sensitive all these values will be converted to lower case. Parsing this string

text/html; charset=utf-8

will create a content type object with primary type "text", subtype "html" and parameter "charset" with value "utf-8". There may be more parameters supplied, but they are not recognized by this class.

Implementation

static ContentType parse(String value) {
  return _ContentType.parse(value);
}