Request

{{APIRef("Fetch API")}}{{AvailableInWorkers}}

The Request interface of the Fetch API represents a resource request.

You can create a new Request object using the {{domxref("Request.Request","Request()")}} constructor, but you are more likely to encounter a Request object being returned as the result of another API operation, such as a service worker {{domxref("FetchEvent.request")}}.

Constructor

• {{domxref("Request.Request","Request()")}}
  • : Creates a new Request object.

Instance properties

• {{domxref("Request.body")}} {{ReadOnlyInline}}
  • : A {{domxref("ReadableStream")}} of the body contents.
• {{domxref("Request.bodyUsed")}} {{ReadOnlyInline}}
  • : Stores true or false to indicate whether or not the body has been used in a request yet.
• {{domxref("Request.cache")}} {{ReadOnlyInline}}
  • : Contains the cache mode of the request (e.g., default, reload, no-cache).
• {{domxref("Request.credentials")}} {{ReadOnlyInline}}
  • : Contains a value controlling whether credentials should be included with the request (e.g., omit, same-origin, include). The default is same-origin.
• {{domxref("Request.destination")}} {{ReadOnlyInline}}
  • : A string describing the type of content being requested.
• {{domxref("Request.duplex")}} {{ReadOnlyInline}} {{experimental_inline}}
  • : The duplex mode of the request, which determines whether the browser must send the entire request before processing the response.
• {{domxref("Request.headers")}} {{ReadOnlyInline}}
  • : Contains the associated {{domxref("Headers")}} object of the request.
• {{domxref("Request.integrity")}} {{ReadOnlyInline}}
  • : Contains the subresource integrity value of the request (e.g., sha256-BpfBw7ivV8q2jLiT13fxDYAe2tJllusRSZ273h2nFSE=).
• {{domxref("Request.isHistoryNavigation")}} {{ReadOnlyInline}}
  • : A boolean indicating whether the request is a history navigation.
• {{domxref("Request.keepalive")}} {{ReadOnlyInline}}
  • : Contains the request's keepalive setting (true or false), which indicates whether the browser will keep the associated request alive if the page that initiated it is unloaded before the request is complete.
• {{domxref("Request.method")}} {{ReadOnlyInline}}
  • : Contains the request's method (GET, POST, etc.)
• {{domxref("Request.mode")}} {{ReadOnlyInline}}
  • : Contains the mode of the request (e.g., cors, no-cors, same-origin, navigate.)
• {{domxref("Request.redirect")}} {{ReadOnlyInline}}
  • : Contains the mode for how redirects are handled. It may be one of follow, error, or manual.
• {{domxref("Request.referrer")}} {{ReadOnlyInline}}
  • : Contains the referrer of the request (e.g., client).
• {{domxref("Request.referrerPolicy")}} {{ReadOnlyInline}}
  • : Contains the referrer policy of the request (e.g., no-referrer).
• {{domxref("Request.signal")}} {{ReadOnlyInline}}
  • : Returns the {{domxref("AbortSignal")}} associated with the request
• {{domxref("Request.url")}} {{ReadOnlyInline}}
  • : Contains the URL of the request.

Instance methods

• {{domxref("Request.arrayBuffer()")}}
  • : Returns a promise that resolves with an {{jsxref("ArrayBuffer")}} representation of the request body.
• {{domxref("Request.blob()")}}
  • : Returns a promise that resolves with a {{domxref("Blob")}} representation of the request body.
• {{domxref("Request.bytes()")}}
  • : Returns a promise that resolves with a {{jsxref("Uint8Array")}} representation of the request body.
• {{domxref("Request.clone()")}}
  • : Creates a copy of the current Request object.
• {{domxref("Request.formData()")}}
  • : Returns a promise that resolves with a {{domxref("FormData")}} representation of the request body.
• {{domxref("Request.json()")}}
  • : Returns a promise that resolves with the result of parsing the request body as {{JSxRef("JSON")}}.
• {{domxref("Request.text()")}}
  • : Returns a promise that resolves with a text representation of the request body.

[!NOTE] The request body functions can be run only once; subsequent calls will reject with TypeError showing that the body stream has already used.

Examples

In the following snippet, we create a new request using the Request() constructor (for an image file in the same directory as the script), then return some property values of the request:

const request = new Request("https://www.mozilla.org/favicon.ico");

const url = request.url;
const method = request.method;
const credentials = request.credentials;

You could then fetch this request by passing the Request object in as a parameter to a {{domxref("Window/fetch", "fetch()")}} call, for example:

fetch(request)
  .then((response) => response.blob())
  .then((blob) => {
    image.src = URL.createObjectURL(blob);
  });

In the following snippet, we create a new request using the Request() constructor with some initial data and body content for an API request which needs a body payload:

const request = new Request("https://example.com", {
  method: "POST",
  body: '{"foo": "bar"}',
});

const url = request.url;
const method = request.method;
const credentials = request.credentials;
const bodyUsed = request.bodyUsed;

[!NOTE] The body can only be a {{domxref("Blob")}}, an {{jsxref("ArrayBuffer")}}, a {{jsxref("TypedArray")}}, a {{jsxref("DataView")}}, a {{domxref("FormData")}}, a {{domxref("URLSearchParams")}}, a {{domxref("ReadableStream")}}, or a {{jsxref("String")}} object, as well as a string literal, so for adding a JSON object to the payload you need to stringify that object.

You could then fetch this API request by passing the Request object in as a parameter to a {{domxref("Window/fetch", "fetch()")}} call, for example and get the response:

fetch(request)
  .then((response) => {
    if (response.status !== 200) {
      throw new Error("Something went wrong on API server!");
    }
    return response.json();
  })
  .then((response) => {
    console.debug(response);
    // …
  })
  .catch((error) => {
    console.error(error);
  });

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• ServiceWorker API
• HTTP access control (CORS)
• HTTP