Node.js: a shim for overriding "http" and "websocket" modules.

Also added stubs for Server.address()
This was done to prevent crashes in some popular frameworks like express

Supports both CommonJS and the new ES Modules system syntax e.g:

app.js:
const http = require('http')

app.mjs:
import http from "http"

Usage on Node 14.16.x and higher:
{
    "type": "external",
    "processes": {"spare": 0},
    "working_directory": '/project',
    "executable": "/usr/bin/env",
    "arguments": [
        "node",
        "--loader",
        "unit-http/require_shim.mjs"
        "--require",
        "unit-http/require_shim",
        "app.js"
    ]
}

Usage on Node 14.15.x and lower:
{
    "type": "external",
    "processes": {"spare": 0},
    "working_directory": '/project',
    "executable": "/usr/bin/env",
    "arguments": [
        "node",
        "--require",
        "unit-http/require_shim",
        "app.js"
    ]
}

docs/changes.xml

@@ -31,6 +31,12 @@ NGINX Unit updated to 1.24.0.
          date="" time=""
          packager="Andrei Belov <defan@nginx.com>">
 
+<change type="feature">
+<para>
+a shim for automatic overriding "http" and "websocket" modules in Node.js.
+</para>
+</change>
+
 <change type="feature">
 <para>
 ability to limit serving of static files by MIME types.

src/nodejs/unit-http/http.js

@@ -5,19 +5,22 @@
 
 'use strict';
 
-const server = require('unit-http/http_server');
-
-const { Server } = server;
+const {
+    Server,
+    ServerRequest,
+    ServerResponse,
+} = require('./http_server');
 
 function createServer (requestHandler) {
     return new Server(requestHandler);
 }
 
+const http = require("http")
 
 module.exports = {
+    ...http,
     Server,
-    STATUS_CODES: server.STATUS_CODES,
     createServer,
-    IncomingMessage: server.ServerRequest,
-    ServerResponse: server.ServerResponse
+    IncomingMessage: ServerRequest,
+    ServerResponse,
 };

src/nodejs/unit-http/http_server.js

@@ -444,17 +444,30 @@ Server.prototype.setTimeout = function setTimeout(msecs, callback) {
 Server.prototype.listen = function (...args) {
     this.unit.listen();
 
-    const cb = args.pop();
-
-    if (typeof cb === 'function') {
-        this.once('listening', cb);
+    if (typeof args[args.length - 1] === 'function') {
+        this.once('listening', args[args.length - 1]);
     }
 
-    this.emit('listening');
+    /*
+     * Some express.js apps use the returned server object inside the listening
+     * callback, so we timeout the listening event to occur after this function
+     * returns.
+     */
+    setImmediate(function() {
+        this.emit('listening')
+    }.bind(this))
 
     return this;
 };
 
+Server.prototype.address = function () {
+    return  {
+        family: "IPv4",
+        address: "127.0.0.1",
+        port: 80
+    }
+}
+
 Server.prototype.emit_request = function (req, res) {
     if (req._websocket_handshake && this._upgradeListenerCount > 0) {
         this.emit('upgrade', req, req.socket);
@@ -530,7 +543,6 @@ function connectionListener(socket) {
 }
 
 module.exports = {
-    STATUS_CODES: http.STATUS_CODES,
     Server,
     ServerResponse,
     ServerRequest,

src/nodejs/unit-http/require_shim.js

@@ -0,0 +1,27 @@
+// can only be ran as part of a --require param on the node process
+if (module.parent && module.parent.id === "internal/preload") {
+    const { Module } = require("module")
+
+    if (!Module.prototype.require.__unit_shim) {
+        const http = require("./http")
+        const websocket = require("./websocket")
+
+        const original = Module.prototype.require;
+
+        Module.prototype.require = function (id) {
+            switch(id) {
+                case "http":
+                case "unit-http":
+                    return http
+
+                case "websocket":
+                case "unit-http/websocket":
+                    return websocket
+            }
+
+            return original.apply(this, arguments);
+        }
+
+        Module.prototype.require.__unit_shim = true;
+    }
+}

src/nodejs/unit-http/require_shim.mjs

@@ -0,0 +1,18 @@
+// must be ran as part of a --loader or --experimental-loader param
+export async function resolve(specifier, context, defaultResolver) {
+    switch (specifier) {
+        case "websocket":
+            return {
+                url: new URL("./websocket.js", import.meta.url).href,
+                format: "cjs"
+            }
+
+        case "http":
+            return {
+                url: new URL("./http.js", import.meta.url).href,
+                format: "cjs"
+            }
+    }
+
+    return defaultResolver(specifier, context, defaultResolver)
+}

test/node/404/app.js

@@ -1,7 +1,6 @@
-#!/usr/bin/env node
 
 var fs = require('fs');
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.writeHead(404, {}).end(fs.readFileSync('404.html'));
 }).listen(7080);

test/node/basic/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.writeHead(200, {'Content-Length': 12, 'Content-Type': 'text/plain'})
        .end('Hello World\n');
 }).listen(7080);

test/node/double_end/app.js

@@ -1,5 +1,4 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.end().end();
 }).listen(7080);

test/node/get_header_names/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.setHeader('DATE', ['date1', 'date2']);
     res.setHeader('X-Header', 'blah');
     res.setHeader('X-Names', res.getHeaderNames());

test/node/get_header_type/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.setHeader('X-Number', 100);
     res.setHeader('X-Type', typeof(res.getHeader('X-Number')));
     res.end();

test/node/get_variables/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     let query = require('url').parse(req.url, true).query;
     res.setHeader('X-Var-1', query.var1);
     res.setHeader('X-Var-2', query.var2);

test/node/has_header/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.setHeader('X-Has-Header', res.hasHeader(req.headers['x-header']) + '');
     res.end();
 }).listen(7080);

test/node/header_name_case/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.setHeader('X-Header', '1');
     res.setHeader('X-header', '2');
     res.setHeader('X-HEADER', '3');

test/node/header_name_valid/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.writeHead(200, {});
     res.setHeader('@$', 'test');
     res.end();

test/node/header_value_object/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.setHeader('X-Header', {});
     res.end();
 }).listen(7080);

test/node/mirror/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     let body = '';
     req.on('data', chunk => {
         body += chunk.toString();

test/node/post_variables/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     let body = '';
     req.on('data', chunk => {
         body += chunk.toString();

test/node/promise_end/app.js

@@ -1,8 +1,7 @@
-#!/usr/bin/env node
 
 var fs = require('fs');
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.write('blah');
 
     Promise.resolve().then(() => {

test/node/promise_handler/app.js

@@ -1,8 +1,7 @@
-#!/usr/bin/env node
 
 var fs = require('fs');
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.end();
 
     if (req.headers['x-write-call']) {

test/node/remove_header/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.setHeader('X-Header', 'test');
     res.setHeader('Was-Header', res.hasHeader('X-Header').toString());
 

test/node/require_shim/es_modules_http/app.mjs

@@ -0,0 +1,6 @@
+import http from "http"
+
+http.createServer(function (req, res) {
+    res.writeHead(200, {'Content-Length': 12, 'Content-Type': 'text/plain'})
+       .end('Hello World\n');
+}).listen(7080);

test/node/require_shim/es_modules_http_indirect/app.js

@@ -0,0 +1 @@
+import("./module.mjs")

test/node/require_shim/es_modules_http_indirect/module.mjs

@@ -0,0 +1,6 @@
+import http from "http"
+
+http.createServer(function (req, res) {
+    res.writeHead(200, {'Content-Length': 12, 'Content-Type': 'text/plain'})
+       .end('Hello World\n');
+}).listen(7080);

test/node/require_shim/es_modules_websocket/app.mjs

@@ -0,0 +1,30 @@
+import http from "http"
+import websocket from "websocket"
+
+let server = http.createServer(function() {});
+let webSocketServer = websocket.server;
+
+server.listen(7080, function() {});
+
+var wsServer = new webSocketServer({
+    maxReceivedMessageSize: 0x1000000000,
+    maxReceivedFrameSize: 0x1000000000,
+    fragmentOutgoingMessages: false,
+    fragmentationThreshold: 0x1000000000,
+    httpServer: server,
+});
+
+wsServer.on('request', function(request) {
+    var connection = request.accept(null);
+
+    connection.on('message', function(message) {
+        if (message.type === 'utf8') {
+            connection.send(message.utf8Data);
+        } else if (message.type === 'binary') {
+            connection.send(message.binaryData);
+        }
+
+  });
+
+  connection.on('close', function(r) {});
+});

test/node/require_shim/es_modules_websocket_indirect/app.js

@@ -0,0 +1 @@
+import("./module.mjs")

test/node/require_shim/es_modules_websocket_indirect/module.mjs

@@ -0,0 +1,30 @@
+import http from "http"
+import websocket from "websocket"
+
+let server = http.createServer(function() {});
+let webSocketServer = websocket.server;
+
+server.listen(7080, function() {});
+
+var wsServer = new webSocketServer({
+    maxReceivedMessageSize: 0x1000000000,
+    maxReceivedFrameSize: 0x1000000000,
+    fragmentOutgoingMessages: false,
+    fragmentationThreshold: 0x1000000000,
+    httpServer: server,
+});
+
+wsServer.on('request', function(request) {
+    var connection = request.accept(null);
+
+    connection.on('message', function(message) {
+        if (message.type === 'utf8') {
+            connection.send(message.utf8Data);
+        } else if (message.type === 'binary') {
+            connection.send(message.binaryData);
+        }
+
+  });
+
+  connection.on('close', function(r) {});
+});

test/node/require_shim/transitive_dependency/app.js

@@ -0,0 +1 @@
+require("./transitive_http")

test/node/require_shim/transitive_dependency/transitive_http.js

@@ -0,0 +1,8 @@
+const http = require("http");
+
+http.createServer(function (req, res) {
+    res.writeHead(200, {'Content-Length': 12, 'Content-Type': 'text/plain'})
+       .end('Hello World\n');
+}).listen(7080);
+
+module.exports = http;

test/node/require_shim/unit_http/app.js

@@ -0,0 +1,4 @@
+require("unit-http").createServer(function (req, res) {
+    res.writeHead(200, {'Content-Length': 12, 'Content-Type': 'text/plain'})
+       .end('Hello World\n');
+}).listen(7080);

test/node/set_header_array/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.setHeader('Set-Cookie', ['tc=one,two,three', 'tc=four,five,six']);
     res.end();
 }).listen(7080);

test/node/status_message/app.js

@@ -1,5 +1,4 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.writeHead(200, 'blah', {'Content-Type': 'text/plain'}).end();
 }).listen(7080);

test/node/update_header/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.setHeader('X-Header', 'test');
     res.setHeader('X-Header', 'new');
     res.end();

test/node/variables/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     let body = '';
     req.on('data', chunk => {
         body += chunk.toString();

test/node/websockets/mirror/app.js

@@ -1,9 +1,6 @@
-#!/usr/bin/env node
 
-server = require('unit-http').createServer(function() {});
-webSocketServer = require('unit-http/websocket').server;
-//server = require('http').createServer(function() {});
-//webSocketServer = require('websocket').server;
+server = require('http').createServer(function() {});
+webSocketServer = require('websocket').server;
 
 server.listen(7080, function() {});
 

test/node/websockets/mirror_fragmentation/app.js

@@ -1,9 +1,6 @@
-#!/usr/bin/env node
 
-server = require('unit-http').createServer(function() {});
-webSocketServer = require('unit-http/websocket').server;
-//server = require('http').createServer(function() {});
-//webSocketServer = require('websocket').server;
+server = require('http').createServer(function() {});
+webSocketServer = require('websocket').server;
 
 server.listen(7080, function() {});
 

test/node/write_before_write_head/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.write('blah');
     res.writeHead(200, {'Content-Type': 'text/plain'}).end();
 }).listen(7080);

test/node/write_buffer/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.writeHead(200, {'Content-Type': 'text/plain'})
        .end(new Buffer([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]));
 }).listen(7080);

test/node/write_callback/app.js

@@ -1,8 +1,7 @@
-#!/usr/bin/env node
 
 var fs = require('fs');
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.writeHead(200, {'Content-Type': 'text/plain'});
     var a = 'world';
     res.write('hello', 'utf8', function() {

test/node/write_multiple/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.writeHead(200, {'Content-Type': 'text/plain', 'Content-Length': 14});
     res.write('write');
     res.write('write2');

test/node/write_return/app.js

@@ -1,6 +1,5 @@
-#!/usr/bin/env node
 
-require('unit-http').createServer(function (req, res) {
+require('http').createServer(function (req, res) {
     res.writeHead(200, {'Content-Type': 'text/plain'})
        .end(res.write('body').toString());
 }).listen(7080);

test/test_node_application.py

@@ -9,13 +9,26 @@ from unit.utils import waitforfiles
 class TestNodeApplication(TestApplicationNode):
     prerequisites = {'modules': {'node': 'all'}}
 
-    def test_node_application_basic(self):
-        self.load('basic')
-
+    def assert_basic_application(self):
         resp = self.get()
         assert resp['headers']['Content-Type'] == 'text/plain', 'basic header'
         assert resp['body'] == 'Hello World\n', 'basic body'
 
+    def test_node_application_basic(self):
+        self.load('basic')
+
+        self.assert_basic_application()
+
+    def test_node_application_require_shim_unit_http(self):
+        self.load('require_shim/unit_http')
+
+        self.assert_basic_application()
+
+    def test_node_application_require_shim_transitive_dependency(self):
+        self.load('require_shim/transitive_dependency')
+
+        self.assert_basic_application()
+
     def test_node_application_seq(self):
         self.load('basic')
 

test/test_node_es_modules.py

@@ -0,0 +1,50 @@
+import pytest
+
+from distutils.version import LooseVersion
+from unit.applications.lang.node import TestApplicationNode
+from unit.applications.websockets import TestApplicationWebsocket
+
+
+class TestNodeESModules(TestApplicationNode):
+    prerequisites = {
+        'modules': {
+            'node': lambda v:  LooseVersion(v) >= LooseVersion("14.16.0")
+        }
+    }
+
+    es_modules = True
+    ws = TestApplicationWebsocket()
+
+    def assert_basic_application(self):
+        resp = self.get()
+        assert resp['headers']['Content-Type'] == 'text/plain', 'basic header'
+        assert resp['body'] == 'Hello World\n', 'basic body'
+
+    def test_node_es_modules_require_shim_http(self):
+        self.load('require_shim/es_modules_http', name="app.mjs")
+
+        self.assert_basic_application()
+
+    def test_node_es_modules_require_shim_http_indirect(self):
+        self.load('require_shim/es_modules_http_indirect', name="app.js")
+
+        self.assert_basic_application()
+
+    def test_node_es_modules_require_shim_websockets(self):
+        self.load('require_shim/es_modules_websocket', name="app.mjs")
+
+        message = 'blah'
+
+        _, sock, _ = self.ws.upgrade()
+
+        self.ws.frame_write(sock, self.ws.OP_TEXT, message)
+        frame = self.ws.frame_read(sock)
+
+        assert message == frame['data'].decode('utf-8'), 'mirror'
+
+        self.ws.frame_write(sock, self.ws.OP_TEXT, message)
+        frame = self.ws.frame_read(sock)
+
+        assert message == frame['data'].decode('utf-8'), 'mirror 2'
+
+        sock.close()

test/unit/applications/lang/node.py

@@ -7,15 +7,16 @@ from unit.utils import public_dir
 
 
 class TestApplicationNode(TestApplicationProto):
+    application_type = "node"
+    es_modules = False
+
     def prepare_env(self, script):
         # copy application
-
         shutil.copytree(
             option.test_dir + '/node/' + script, option.temp_dir + '/node'
         )
 
         # copy modules
-
         shutil.copytree(
             option.current_dir + '/node/node_modules',
             option.temp_dir + '/node/node_modules',
@@ -26,6 +27,19 @@ class TestApplicationNode(TestApplicationProto):
     def load(self, script, name='app.js', **kwargs):
         self.prepare_env(script)
 
+        if self.es_modules:
+            arguments = [
+                "node",
+                "--loader",
+                "unit-http/require_shim.mjs",
+                "--require",
+                "unit-http/require_shim",
+                name,
+            ]
+
+        else:
+            arguments = ["node", "--require", "unit-http/require_shim", name]
+
         self._load_conf(
             {
                 "listeners": {
@@ -36,7 +50,8 @@ class TestApplicationNode(TestApplicationProto):
                         "type": "external",
                         "processes": {"spare": 0},
                         "working_directory": option.temp_dir + '/node',
-                        "executable": name,
+                        "executable": '/usr/bin/env',
+                        "arguments": arguments,
                     }
                 },
             },

test/unit/check/node.py

@@ -1,6 +1,15 @@
 import os
+import subprocess
 
 
 def check_node(current_dir):
-    if os.path.exists(current_dir + '/node/node_modules'):
-        return True
+    if not os.path.exists(current_dir + '/node/node_modules'):
+        return None
+
+    try:
+        v_bytes = subprocess.check_output(['/usr/bin/env', 'node', '-v'])
+
+        return [str(v_bytes, 'utf-8').lstrip('v').rstrip()]
+
+    except subprocess.CalledProcessError:
+        return None