Express Static Stream

A simple middleware to serve static files via compressed streams.

The feature can be toggled and customized.

Prerequisites

The middleware requires Express to be installed

Usage

import http from "http";
import express from "express";
import expressStaticStream from "express-static-stream";

// ...

const app = express();

// other middleware here ...

// should be last because it does not provide a NextHandler for GET requests
app.use(expressStaticStream(<options>));

const server = http.createServer(app);
server.listen(<port>, () => { console.log("Http server listening on port <port>"); });

Options

The middleware requires an option object as parameter.
Available options are listed below:

• clientRoot: string, required
  Defines the root folder from which to get the files.
• streamFiles: boolean, optional default: true
  Enables file streaming.
• preferredEncoding: StreamEncoding (import type StreamEncoding), optional default: gzip
  Specifies the preferred encoding when it could not be assumed from previous routes and accepted encoding is ambigous.
• compressionSizeThreshold: number, optional default: 0
  Specifies the threshold for the file size that is required for compression to take effect in bytes.
• setOriginalContentLength: boolean, optional default: true
  Specifies whether to include the original content length as a response header (X-Original-Content-Length).

NOTE: You can also set up the middleware using only a clientRoot. Simply replace the options object with the clientRoot as string: app.use(expressStaticStream(<clientRoot>)). This will set default values for the options.
NOTE: Alternatively you can also append options without clientRoot like app.use(expressStaticStream(<clientRoot>, <options-without-clientRoot>))

Additional Information

The middleware can detect the compression from the request or response.
For this to work either the request header Accept-Encondig or the response header Content-Encoding needs to be set in a previous route.
When transmitting the request header Accept-Encoding and it contains only one enconding it will be applied if possible. If it contains more than one encoding the specified Content-Encoding response header or if that is not specified the preferred encoding will be used if it is included in the Accept-Encondig request header. Otherwise the first accepted compression will be tried and if that is not possible no compression will be applied.

License

Copyright 2024 Benedikt Warmesbach

Licensed under the Apache license, version 2.0 (the "license"); You may not use this file except in compliance with the license. You may obtain a copy of the license at:

http://www.apache.org/licenses/LICENSE-2.0.html

Unless required by applicable law or agreed to in writing, software distributed under the license is distributed on an "as is" basis, without warranties or conditions of any kind, either express or implied. See the license for the specific language governing permissions and limitations under the license.