feat: threshold

.github/workflows/test.yaml

@@ -0,0 +1,29 @@
+name: Test
+
+on:
+  - pull_request
+
+jobs:
+  test:
+    name: Node.js v${{ matrix.node }}
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        node: ['20', '22', '23']
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node }}
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run tests
+        run: npm test 

.gitignore

@@ -1,2 +1 @@
 node_modules
-package-lock.json

CHANGELOG.md

@@ -1,3 +1,7 @@
+### 0.1.8 / 2024-11-09
+
+- Add `threshold` option to control when compression is applied
+
 ### 0.1.7 / 2019-06-10
 
 - Use the `Buffer.alloc()` and `Buffer.from()` functions instead of the unsafe

README.md

@@ -8,7 +8,7 @@ WebSocket protocol extension as a plugin for
 ## Installation
 
 ```
-$ npm install permessage-deflate
+$ npm install permessage-deflate2
 ```
 
 ## Usage
@@ -32,7 +32,8 @@ var Extensions = require('websocket-extensions'),
 
 deflate = deflate.configure({
   level: zlib.Z_BEST_COMPRESSION,
-  maxWindowBits: 13
+  maxWindowBits: 13,
+  threshold: 100 // optional, defaults to 0 (always compress)
 });
 
 var exts = new Extensions();
@@ -45,6 +46,7 @@ the peer, and those that are negotiated as part of the protocol. The settings
 only affecting the compressor are described fully in the [zlib
 documentation](http://nodejs.org/api/zlib.html#zlib_options):
 
+- `threshold`: sets the minimum size of messages to be compressed, defaults to 0
 - `level`: sets the compression level, can be an integer from `0` to `9`, or one
   of the constants `zlib.Z_NO_COMPRESSION`, `zlib.Z_BEST_SPEED`,
   `zlib.Z_BEST_COMPRESSION`, or `zlib.Z_DEFAULT_COMPRESSION`

lib/permessage_deflate.js

@@ -12,6 +12,7 @@ var VALID_OPTIONS = [
   'maxWindowBits',
   'requestNoContextTakeover',
   'requestMaxWindowBits',
+  'threshold',
   'zlib'
 ];
 

lib/session.js

@@ -8,6 +8,7 @@ var Session = function(options) {
   this._level    = common.fetch(options, 'level',    zlib.Z_DEFAULT_COMPRESSION);
   this._memLevel = common.fetch(options, 'memLevel', zlib.Z_DEFAULT_MEMLEVEL);
   this._strategy = common.fetch(options, 'strategy', zlib.Z_DEFAULT_STRATEGY);
+  this._threshold = common.fetch(options, 'threshold', 0);
 
   this._acceptNoContextTakeover  = common.fetch(options, 'noContextTakeover', false);
   this._acceptMaxWindowBits      = common.fetch(options, 'maxWindowBits', undefined);
@@ -67,12 +68,18 @@ Session.prototype.processIncomingMessage = function(message, callback) {
 };
 
 Session.prototype.processOutgoingMessage = function(message, callback) {
+  // Skip compression for small messages
+  if (message.data.length < this._threshold) {
+    message.rsv1 = false;
+    return callback(null, message);
+  }
+
   if (this._lockOut) return this._queueOut.push([message, callback]);
 
   var deflate = this._getDeflate(),
-      chunks  = [],
-      length  = 0,
-      self    = this;
+      totalLength = 0,
+      chunks = [],
+      self = this;
 
   if (this._deflate) this._lockOut = true;
 
@@ -92,10 +99,11 @@ Session.prototype.processOutgoingMessage = function(message, callback) {
 
   var onData = function(data) {
     chunks.push(data);
-    length += data.length;
+    totalLength += data.length;
   };
 
   var onError = function(error) {
+    chunks = null; // Help GC
     return_(error, null);
   };
 
@@ -104,8 +112,26 @@ Session.prototype.processOutgoingMessage = function(message, callback) {
   deflate.write(message.data);
 
   var onFlush = function() {
-    var data = Buffer.concat(chunks, length);
-    message.data = data.slice(0, data.length - 4);
+    if (totalLength === 0) {
+      chunks = null;
+      message.data = Buffer.alloc(0);
+    } else {
+      // allocUnsafe is safe here because:
+      // 1. We know the exact size needed (totalLength)
+      // 2. We immediately fill the entire buffer with our compressed data
+      // 3. No uninitialized memory is exposed to users
+      var finalBuffer = Buffer.allocUnsafe(totalLength);
+      var offset = 0;
+
+      for (var i = 0; i < chunks.length; i++) {
+        chunks[i].copy(finalBuffer, offset);
+        offset += chunks[i].length;
+      }
+
+      chunks = null; // Help GC
+      message.data = finalBuffer.slice(0, finalBuffer.length - 4);
+    }
+
     message.rsv1 = true;
     return_(null, message);
   };

package.json

@@ -1,34 +1,34 @@
 {
-          "name": "permessage-deflate",
-          "description": "Per-message DEFLATE compression extension for WebSocket connections",
-          "homepage": "https://github.com/faye/permessage-deflate-node",
-          "author": "James Coglan <[email protected]> (http://jcoglan.com/)",
-          "keywords": [
-                    "websocket",
-                    "compression",
-                    "deflate"
-          ],
-          "license": "Apache-2.0",
-          "version": "0.1.7",
-          "engines": {
-                    "node": ">=0.8.0"
-          },
-          "files": [
-                    "lib"
-          ],
-          "main": "./lib/permessage_deflate",
-          "dependencies": {
-                    "safe-buffer": "*"
-          },
-          "devDependencies": {
-                    "jstest": "*"
-          },
-          "scripts": {
-                    "test": "jstest spec/runner.js"
-          },
-          "repository": {
-                    "type": "git",
-                    "url": "git://github.com/faye/permessage-deflate-node.git"
-          },
-          "bugs": "https://github.com/faye/permessage-deflate-node/issues"
+  "name": "permessage-deflate2",
+  "description": "Per-message DEFLATE compression extension for WebSocket connections, with threshold!",
+  "homepage": "https://github.com/leonardoventurini/permessage-deflate2",
+  "author": "James Coglan <[email protected]> (http://jcoglan.com/), Leonardo Venturini <[email protected]>",
+  "keywords": [
+    "websocket",
+    "compression",
+    "deflate"
+  ],
+  "license": "Apache-2.0",
+  "version": "0.1.8-alpha.1",
+  "engines": {
+    "node": ">=20.0.0"
+  },
+  "files": [
+    "lib"
+  ],
+  "main": "./lib/permessage_deflate",
+  "dependencies": {
+    "safe-buffer": "*"
+  },
+  "devDependencies": {
+    "jstest": "*"
+  },
+  "scripts": {
+    "test": "jstest spec/runner.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/leonardoventurini/permessage-deflate2.git"
+  },
+  "bugs": "https://github.com/leonardoventurini/permessage-deflate2/issues"
 }

spec/client_session_spec.js

@@ -346,4 +346,57 @@ test.describe("ClientSession", function() { with(this) {
       processOutgoingMessage()
     }})
   }})
+
+  describe("with threshold", function() { with(this) {
+    define("options", { threshold: 100 })
+
+    it("does not compress messages smaller than threshold", function() { with(this) {
+      this.message = { data: Buffer.alloc(50).fill("x"), rsv1: true }
+      activate()
+      expect(zlib, "createDeflateRaw").exactly(0)
+      processOutgoingMessage()
+    }})
+
+    it("compresses messages larger than threshold", function() { with(this) {
+      this.message = { data: Buffer.alloc(150).fill("x"), rsv1: true }
+      activate()
+      expect(zlib, "createDeflateRaw").given({ windowBits: 15, level: level, memLevel: memLevel, strategy: strategy }).returns(deflate)
+      processOutgoingMessage()
+    }})
+
+    it("sets rsv1 to false when skipping compression", function() { with(this) {
+      this.message = { data: Buffer.alloc(50).fill("x"), rsv1: true }
+      activate()
+      processOutgoingMessage(function(error, message) {
+        assertEqual(false, message.rsv1)
+      })
+    }})
+
+    it("maintains rsv1 when compressing", function() { with(this) {
+      this.message = { data: Buffer.alloc(150).fill("x"), rsv1: true }
+      activate()
+      stub(zlib, "createDeflateRaw").returns(deflate)
+      processOutgoingMessage(function(error, message) {
+        assertEqual(true, message.rsv1)
+      })
+    }})
+
+    it("handles threshold of 0 (always compress)", function() { with(this) {
+      this.ext = PermessageDeflate.configure({ threshold: 0 })
+      this.session = ext.configure({ zlib: zlib }).createClientSession()
+      this.message = { data: Buffer.alloc(1).fill("x"), rsv1: true }
+      activate()
+      expect(zlib, "createDeflateRaw").given({ windowBits: 15, level: level, memLevel: memLevel, strategy: strategy }).returns(deflate)
+      processOutgoingMessage()
+    }})
+
+    it("handles undefined threshold (always compress)", function() { with(this) {
+      this.ext = PermessageDeflate.configure({})
+      this.session = ext.configure({ zlib: zlib }).createClientSession()
+      this.message = { data: Buffer.alloc(1).fill("x"), rsv1: true }
+      activate()
+      expect(zlib, "createDeflateRaw").given({ windowBits: 15, level: level, memLevel: memLevel, strategy: strategy }).returns(deflate)
+      processOutgoingMessage()
+    }})
+  }})
 }})