HTTP Basic Authentication

Note

This example Worker makes use of the Node.js Buffer API, which is available as part of the Worker's runtime Node.js compatibility mode. To run this Worker, you will need to enable the nodejs_compat compatibility flag.

Caution when using in production

This code is provided as a sample, and is not suitable for production use. Basic Authentication sends credentials unencrypted, and must be used with an HTTPS connection to be considered secure. For a production-ready authentication system, consider using Cloudflare Access ↗.

JavaScript

/**
 * Shows how to restrict access using the HTTP Basic schema.
 * @see https://developer.mozilla.org/en-US/docs/Web/HTTP/Authentication
 * @see https://tools.ietf.org/html/rfc7617
 *
 */

import { Buffer } from "node:buffer";

const encoder = new TextEncoder();

/**
 * Protect against timing attacks by safely comparing values using `timingSafeEqual`.
 * Refer to https://developers.cloudflare.com/workers/runtime-apis/web-crypto/#timingsafeequal for more details
 * @param {string} a
 * @param {string} b
 * @returns {boolean}
 */
function timingSafeEqual(a, b) {
  const aBytes = encoder.encode(a);
  const bBytes = encoder.encode(b);

  if (aBytes.byteLength !== bBytes.byteLength) {
    // Strings must be the same length in order to compare
    // with crypto.subtle.timingSafeEqual
    return false;
  }

  return crypto.subtle.timingSafeEqual(aBytes, bBytes);
}

export default {
  /**
   *
   * @param {Request} request
   * @param {{PASSWORD: string}} env
   * @returns
   */
  async fetch(request, env) {
    const BASIC_USER = "admin";

    // You will need an admin password. This should be
    // attached to your Worker as an encrypted secret.
    // Refer to https://developers.cloudflare.com/workers/configuration/secrets/
    const BASIC_PASS = env.PASSWORD ?? "password";

    const url = new URL(request.url);

    switch (url.pathname) {
      case "/":
        return new Response("Anyone can access the homepage.");

      case "/logout":
        // Invalidate the "Authorization" header by returning a HTTP 401.
        // We do not send a "WWW-Authenticate" header, as this would trigger
        // a popup in the browser, immediately asking for credentials again.
        return new Response("Logged out.", { status: 401 });

      case "/admin": {
        // The "Authorization" header is sent when authenticated.
        const authorization = request.headers.get("Authorization");
        if (!authorization) {
          return new Response("You need to login.", {
            status: 401,
            headers: {
              // Prompts the user for credentials.
              "WWW-Authenticate": 'Basic realm="my scope", charset="UTF-8"',
            },
          });
        }
        const [scheme, encoded] = authorization.split(" ");

        // The Authorization header must start with Basic, followed by a space.
        if (!encoded || scheme !== "Basic") {
          return new Response("Malformed authorization header.", {
            status: 400,
          });
        }

        const credentials = Buffer.from(encoded, "base64").toString();

        // The username & password are split by the first colon.
        //=> example: "username:password"
        const index = credentials.indexOf(":");
        const user = credentials.substring(0, index);
        const pass = credentials.substring(index + 1);

        if (
          !timingSafeEqual(BASIC_USER, user) ||
          !timingSafeEqual(BASIC_PASS, pass)
        ) {
          return new Response("You need to login.", {
            status: 401,
            headers: {
              // Prompts the user for credentials.
              "WWW-Authenticate": 'Basic realm="my scope", charset="UTF-8"',
            },
          });
        }

        return new Response("🎉 You have private access!", {
          status: 200,
          headers: {
            "Cache-Control": "no-store",
          },
        });
      }
    }

    return new Response("Not Found.", { status: 404 });
  },
};

TypeScript

/**
 * Shows how to restrict access using the HTTP Basic schema.
 * @see https://developer.mozilla.org/en-US/docs/Web/HTTP/Authentication
 * @see https://tools.ietf.org/html/rfc7617
 *
 */

import { Buffer } from "node:buffer";

const encoder = new TextEncoder();

/**
 * Protect against timing attacks by safely comparing values using `timingSafeEqual`.
 * Refer to https://developers.cloudflare.com/workers/runtime-apis/web-crypto/#timingsafeequal for more details
 */
function timingSafeEqual(a: string, b: string) {
  const aBytes = encoder.encode(a);
  const bBytes = encoder.encode(b);

  if (aBytes.byteLength !== bBytes.byteLength) {
    // Strings must be the same length in order to compare
    // with crypto.subtle.timingSafeEqual
    return false;
  }

  return crypto.subtle.timingSafeEqual(aBytes, bBytes);
}

interface Env {
  PASSWORD: string;
}
export default {
  async fetch(request, env): Promise<Response> {
    const BASIC_USER = "admin";

    // You will need an admin password. This should be
    // attached to your Worker as an encrypted secret.
    // Refer to https://developers.cloudflare.com/workers/configuration/secrets/
    const BASIC_PASS = env.PASSWORD ?? "password";

    const url = new URL(request.url);

    switch (url.pathname) {
      case "/":
        return new Response("Anyone can access the homepage.");

      case "/logout":
        // Invalidate the "Authorization" header by returning a HTTP 401.
        // We do not send a "WWW-Authenticate" header, as this would trigger
        // a popup in the browser, immediately asking for credentials again.
        return new Response("Logged out.", { status: 401 });

      case "/admin": {
        // The "Authorization" header is sent when authenticated.
        const authorization = request.headers.get("Authorization");
        if (!authorization) {
          return new Response("You need to login.", {
            status: 401,
            headers: {
              // Prompts the user for credentials.
              "WWW-Authenticate": 'Basic realm="my scope", charset="UTF-8"',
            },
          });
        }
        const [scheme, encoded] = authorization.split(" ");

        // The Authorization header must start with Basic, followed by a space.
        if (!encoded || scheme !== "Basic") {
          return new Response("Malformed authorization header.", {
            status: 400,
          });
        }

        const credentials = Buffer.from(encoded, "base64").toString();

        // The username and password are split by the first colon.
        //=> example: "username:password"
        const index = credentials.indexOf(":");
        const user = credentials.substring(0, index);
        const pass = credentials.substring(index + 1);

        if (
          !timingSafeEqual(BASIC_USER, user) ||
          !timingSafeEqual(BASIC_PASS, pass)
        ) {
          return new Response("You need to login.", {
            status: 401,
            headers: {
              // Prompts the user for credentials.
              "WWW-Authenticate": 'Basic realm="my scope", charset="UTF-8"',
            },
          });
        }

        return new Response("🎉 You have private access!", {
          status: 200,
          headers: {
            "Cache-Control": "no-store",
          },
        });
      }
    }

    return new Response("Not Found.", { status: 404 });
  },
} satisfies ExportedHandler<Env>;

Rust

use base64::prelude::*;
use worker::*;

#[event(fetch)]
async fn fetch(req: Request, env: Env, _ctx: Context) -> Result<Response> {
    let basic_user = "admin";
    // You will need an admin password. This should be
    // attached to your Worker as an encrypted secret.
    // Refer to https://developers.cloudflare.com/workers/configuration/secrets/
    let basic_pass = match env.secret("PASSWORD") {
        Ok(s) => s.to_string(),
        Err(_) => "password".to_string(),
    };
    let url = req.url()?;

    match url.path() {
        "/" => Response::ok("Anyone can access the homepage."),
        // Invalidate the "Authorization" header by returning a HTTP 401.
        // We do not send a "WWW-Authenticate" header, as this would trigger
        // a popup in the browser, immediately asking for credentials again.
        "/logout" => Response::error("Logged out.", 401),
        "/admin" => {
            // The "Authorization" header is sent when authenticated.
            let authorization = req.headers().get("Authorization")?;
            if authorization == None {
                let mut headers = Headers::new();
                // Prompts the user for credentials.
                headers.set(
                    "WWW-Authenticate",
                    "Basic realm='my scope', charset='UTF-8'",
                )?;
                return Ok(Response::error("You need to login.", 401)?.with_headers(headers));
            }
            let authorization = authorization.unwrap();
            let auth: Vec<&str> = authorization.split(" ").collect();
            let scheme = auth[0];
            let encoded = auth[1];

            // The Authorization header must start with Basic, followed by a space.
            if encoded == "" || scheme != "Basic" {
                return Response::error("Malformed authorization header.", 400);
            }

            let buff = BASE64_STANDARD.decode(encoded).unwrap();
            let credentials = String::from_utf8_lossy(&buff);
            // The username & password are split by the first colon.
            //=> example: "username:password"
            let credentials: Vec<&str> = credentials.split(':').collect();
            let user = credentials[0];
            let pass = credentials[1];

            if user != basic_user || pass != basic_pass {
                let mut headers = Headers::new();
                // Prompts the user for credentials.
                headers.set(
                    "WWW-Authenticate",
                    "Basic realm='my scope', charset='UTF-8'",
                )?;
                return Ok(Response::error("You need to login.", 401)?.with_headers(headers));
            }

            let mut headers = Headers::new();
            headers.set("Cache-Control", "no-store")?;
            Ok(Response::ok("🎉 You have private access!")?.with_headers(headers))
        }
        _ => Response::error("Not Found.", 404),
    }
}