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http-transform

0.0.14 • Public • Published

http-transform

An extension of the Node.js Transform stream that additionally supports the HTTP header interface.

  • RequestPair: creates a pair of related streams, one writable, one readable; anything written to the clientWritableSide is readable on the serverReadableSide.
  • ResponsePair: creates a pair of related streams, one writable, one readable; anything written to the serverWritableSide is readable on the clientReadableSide.
  • ResponsePassThrough: creates a Duplex stream that also stores HTTP headers; anything written to it becomes readable. Headers are passed through as exactly as possible. It should typically possible to pipe a response through a ResponsePassThrough instance with no change in behavior. This is typically used to programmatically create a response that's readable the same way a Node.js req object is, and can be piped to a res server response object.

TODO

  • RequestPassThrough — Request variation of ResponsePassThrough
  • RequestThroughOrigin — subclass of RequestPair that applies header normalizations, as if the request is actually going through the network.
  • ResponseThroughOrigin — subclass of ResponsePair that applies header normalizations, as if the response is actually going through the network.

Features

Mock a readable response object:

function makeResponse(){
    const res = new ResponsePassThrough;
    res.setHeader('Content-Type', 'text/plain')
    res.write('Line\r\n');
    return res.readableClientSide;
}

Add a Content-Type to a ReadableStream:

const http = require('http');
const { createReadStream } = require('fs');
const { inherits } = require('util');
const { ResponseTransform } = require('.');
const { markdown } = require( "markdown" );
 
class MarkdownTransform extends ResponseTransform {
    constructor() {
        super();
        const [ input, output ] = this.makeStreams();
        output.setHeader('Content-Type', 'application/xhtml+xml');
        output.write('<!DOCTYPE html>');
        output.write('<html xmlns="http://www.w3.org/1999/xhtml" lang="en" dir="ltr">');
        output.write('	<head>');
        output.write('		<meta charset="UTF-8" />');
        output.write('		<title></title>');
        output.write('		<meta name="description" content="" />');
        output.write('	</head>');
        output.write('	<body>');
        output.write('		<main id="main-content">');
        input.once('readable', async function(){
            var source = '';
            for await(var chunk of input) source += chunk.toString();
            output.write(markdown.toHTML(this.sourceContents));
            output.write('		</main>');
            output.write('	</body>');
            output.write('</html>');
            output.end();
        });
    }
};
 
const server = http.createServer(function(req, res) {
    if(req.url!=='/'){
        res.statusCode = 404;
        res.end('404 Not Found\n');
        return;
    }
    if(req.method!=='GET'){
        res.statusCode = 501;
        res.setHeader('Allow', 'GET');
        res.end('501 Not Implemented\n');
        return;
    }
    createReadStream('README.md').pipe(new MarkdownTransform).pipe(res);
});
server.listen(8080);

API

ResponseTransform

A subclass of the Node.js Transform that also transforms HTTP headers and status code.

Properties/methods:

  • headersReady - A promise that resolves when headers have been committed and are ready to be read

PassThrough

Accepts input and passes it to the write target(s).

This can be used to convert a typical ReadableStream into one that produces HTTP headers.

Headers

Headers is a simple container for HTTP headers. Its methods and properties are imported into ServerResponseTransform.

Properties/methods, as implemented in Node.js:

  • statusCode
  • statusMessage
  • getHeader(name)
  • setHeader(name, value)
  • removeHeader(name)
  • getHeaderNames()
  • getHeaders()
  • hasHeader(name)
  • pipe(dst)

Additional methods:

  • addHeader(name, value)
  • pipeHeaders(dst) - copy status/message fields to dst
  • pipeMessage(dst) - copy status, message fields, and pipe the stream to dst

Readme

Keywords

Package Sidebar

Install

npm i http-transform

Repository

github.com/awwright/node-http-transform

Homepage

github.com/awwright/node-http-transform#readme

Weekly Downloads

0

Version

0.0.14

License

Unlicense

Unpacked Size

87.4 kB

Total Files

24

Last publish

Collaborators

  • acubed
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