http

http is a module to provide HTTP client and server implementations.

Server

Server APIs utilizing Deno’s HTTP server APIs.

import { serve } from "https://deno.land/std@0.151.0/http/server.ts";

serve(() => new Response("Hello World\n"));

console.log("http://localhost:8000/");

File Server

A small program for serving local files over HTTP.

deno run --allow-net --allow-read https://deno.land/std/http/file_server.ts
> HTTP server listening on http://localhost:4507/

HTTP Status Code and Status Text

Helper for processing status code and status text.

import {
  Status,
  STATUS_TEXT,
} from "https://deno.land/std@0.151.0/http/http_status.ts";

console.log(Status.NotFound); //=> 404
console.log(STATUS_TEXT[Status.NotFound]); //=> "Not Found"

HTTP errors

Provides error classes for each HTTP error status code as well as utility functions for handling HTTP errors in a structured way.

For example throwing an error and detecting thrown errors as HTTP errors, and setting values in a response.

import {
  errors,
  isHttpError,
} from "https://deno.land/std@0.151.0/http/http_errors.ts";

try {
  throw new errors.NotFound();
} catch (e) {
  if (isHttpError(e)) {
    const response = new Response(e.message, { status: e.status });
  } else {
    throw e;
  }
}

Also the createHttpError() function can be used to create errors:

import { createHttpError } from "https://deno.land/std@0.151.0/http/http_errors.ts";
import { Status } from "https://deno.land/std@0.151.0/http/http_status.ts";

try {
  throw createHttpError(
    Status.BadRequest,
    "The request was bad.",
    { expose: false },
  );
} catch (e) {
  // handle errors
}

`errors`

A namespace that contains each error constructor. Each error extends HTTPError and provides .status and .expose properties, where the .status will be an error Status value and .expose indicates if information, like a stack trace, should be shared in the response.

By default, .expose is set to false in server errors, and true for client errors.

`HttpError`

The base case for all other HTTP errors, which extends Error.

`createHttpError()`

A factory function which provides a way to create errors. It takes up to 3 arguments, the error Status, an message, which defaults to the status text and error options, which incudes the expose property to set the .expose value on the error.

`isHttpError()`

A type guard that checks if a value is an HTTP error.

Negotiation

A set of functions which can be used to negotiate content types, encodings and languages when responding to requests.

Note: some libraries include accept charset functionality by analyzing the Accept-Charset header. This is a legacy header that clients omit and servers should ignore therefore is not provided.

accepts()

Used to determine what content type the requestor supports via analyzing the Accept header. Just passing a request to the accept function will return the clients accepted content in order of preference:

import { accepts } from "https://deno.land/std@0.151.0/http/negotiation.ts";

const req = new Request("https://example.com/", {
  headers: {
    "accept":
      "text/html, application/xhtml+xml, application/xml;q=0.9, image/webp, */*;q=0.8",
  },
});

console.log(accepts(req));
// [
//   "text/html",
//   "application/xhtml+xml",
//   "image/webp",
//   "application/xml",
//   "*/*",
// ]

Providing supported content types will cause the function to return the “best” match:

import { accepts } from "https://deno.land/std@0.151.0/http/negotiation.ts";

const req = new Request("https://example.com/", {
  headers: {
    "accept":
      "text/html, application/xhtml+xml, application/xml;q=0.9, image/webp, */*;q=0.8",
  },
});

accepts(req, "text/html", "image/webp"); // "text/html";

acceptsEncodings()

Used to determine what content encoding the requestor supports via analyzing the Accept-Encoding header. Just passing a request to the function will return the clients accepted content encodings in order of preference:

import { acceptsEncodings } from "https://deno.land/std@0.151.0/http/negotiation.ts";

const req = new Request("https://example.com/", {
  headers: { "accept-encoding": "deflate, gzip;q=1.0, *;q=0.5" },
});

acceptsEncodings(req); // ["deflate", "gzip", "*"]

Providing the supported content encodings will cause the function to return the “best” match. Note that "indentity" should always be included as it is the base encoding:

import { acceptsEncodings } from "https://deno.land/std@0.151.0/http/negotiation.ts";

const req = new Request("https://example.com/", {
  headers: { "accept-encoding": "deflate, gzip;q=1.0, *;q=0.5" },
});

acceptsEncodings(req, "gzip", "identity"); // "gzip"

acceptsLanguages()

Used to determine what content languages the requestor supports via analyzing the Accept-Language header. Just passing a request to the function will return the clients accepted content languages in order of preference:

import { acceptsLanguages } from "https://deno.land/std@0.151.0/http/negotiation.ts";

const req = new Request("https://example.com/", {
  headers: {
    "accept-language": "fr-CH, fr;q=0.9, en;q=0.8, de;q=0.7, *;q=0.5",
  },
});

acceptsLanguages(req); // ["fr-CH", "fr", "en", "de", "*"]

Providing the supported content languages will cause the function to return the “best” match:

import { acceptsLanguages } from "https://deno.land/std@0.151.0/http/negotiation.ts";

const req = new Request("https://example.com/", {
  headers: {
    "accept-language": "fr-CH, fr;q=0.9, en;q=0.8, de;q=0.7, *;q=0.5",
  },
});

acceptsLanguages(req, "en-gb", "en-us", "en"); // "en"

Helpers to manipulate the Cookie header.

getCookies

import { getCookies } from "https://deno.land/std@0.151.0/http/cookie.ts";

const headers = new Headers();
headers.set("Cookie", "full=of; tasty=chocolate");

const cookies = getCookies(headers);
console.log(cookies); // { full: "of", tasty: "chocolate" }

setCookie

import {
  Cookie,
  setCookie,
} from "https://deno.land/std@0.151.0/http/cookie.ts";

const headers = new Headers();
const cookie: Cookie = { name: "Space", value: "Cat" };
setCookie(headers, cookie);

const cookieHeader = headers.get("set-cookie");
console.log(cookieHeader); // Space=Cat

deleteCookie

Note: Deleting a Cookie will set its expiration date before now. Forcing the browser to delete it.

import { deleteCookie } from "https://deno.land/std@0.151.0/http/cookie.ts";

const headers = new Headers();
deleteCookie(headers, "deno");

const cookieHeader = headers.get("set-cookie");
console.log(cookieHeader); // deno=; Expires=Thus, 01 Jan 1970 00:00:00 GMT

Note: It is possible to pass the exact same path and domain attributes that were used to set the cookie.

import { deleteCookie } from "https://deno.land/std@0.151.0/http/cookie.ts";

const headers = new Headers();
deleteCookie(headers, "deno", { path: "/", domain: "deno.land" });

Note: At the moment multiple Set-Cookie in a Response is not handled.