Request

The Request interface of Azion Runtime: the incoming request a function receives, its constructor, its read-only properties, and its methods.

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The Request interface represents an HTTP request in the Fetch API of Azion Runtime. A function receives each incoming request as a Request: the request argument of a fetch(request, env, ctx) handler, or event.request in a listener that receives a FetchEvent. You also construct a Request to pass to fetch(). For more information, refer to Request on MDN Web Docs.

Under azion dev, an assignment to a property of the incoming request is ignored without an error, and request.metadata is undefined.

Constructor

new Request(input, init)
ParameterTypeRequiredDescription
inputString or RequestYesResource to request, as a URL or as a Request object.
initObjectNoOptions that set the method, the headers, the body, and the redirect mode of the request.

The init object takes these options:

OptionTypeDescription
methodStringRequest method, such as GET or POST.
headersHeaders object or a plain objectHeaders of the request.
bodyString, or the body of another requestContent of the request body.
redirectStringRedirect mode: follow, error, or manual.

The constructor normalizes the URL: new Request('https://example.com') has the url https://example.com/.

Properties

PropertyTypeDescription
bodyReadableStream or nullBody content, read as a stream. null when the request has no body, such as an incoming GET request. For more information, refer to ReadableStream.
bodyUsedBooleanfalse until the body is read, then true.
headersHeadersHeaders of the request.
metadataObjectMetadata of the incoming request, available in a deployed function. For more information, refer to Metadata.
methodStringRequest method, such as GET or POST.
redirectStringRedirect mode: follow, error, or manual. An incoming request has follow.
urlStringFull URL of the request, including the query string, such as https://example.com/a?b=1.

Every property of the incoming request is read-only. In a deployed function, an assignment such as request.url = 'https://example.com/' throws TypeError: Cannot set property url of [object Request] which has only a getter. To change a request, construct a Request and pass the values you keep in init, as the example below does.

Methods

MethodDescription
request.text()Reads the body as a string. Returns a promise. After the call, bodyUsed is true.

A deployed request also carries arrayBuffer(), blob(), bytes(), clone(), formData(), and json(). For their behavior, refer to Request on MDN Web Docs.

Example

This listener builds a Request for https://example.com from the method, headers, body, and redirect mode of the incoming request, then returns three properties of the request it built with Response.json():

JavaScript
01addEventListener("fetch", (event) => {
02 const request = event.request;
03 const url = "https://example.com";
04
05 const myRequest = new Request(url, {
06 body: request.body,
07 headers: request.headers,
08 method: request.method,
09 redirect: request.redirect,
10 });
11
12 event.respondWith(
13 Response.json({
14 method: myRequest.method,
15 url: myRequest.url,
16 redirect: myRequest.redirect,
17 })
18 );
19});

For an incoming GET request, the function returns these values from the request it builds:

JSON
01{
02 "method": "GET",
03 "url": "https://example.com/",
04 "redirect": "follow"
05}
fetch

How a function sends a Request and receives a response.

FetchEvent

The event that carries the incoming request as event.request.

Response

How to build the response a function returns.

Web APIs

The other Web APIs that Azion Runtime supports.