From ff0facf21e7b36f963089316e2ed427770ce08aa Mon Sep 17 00:00:00 2001
From: Colin GILLE <colin.gille@blgcloud.com>
Date: Fri, 2 Feb 2024 15:38:17 +0100
Subject: [PATCH] Don't store request specific data into the Layer object,
 should be immutable

---
 index.js           | 41 ++++++++++++-----------------------------
 lib/layer.js       | 29 +++++++++++++----------------
 test/req.params.js | 22 ++++++++++++++++++++++
 3 files changed, 47 insertions(+), 45 deletions(-)

diff --git a/index.js b/index.js
index 362bccd..cb3a93b 100644
--- a/index.js
+++ b/index.js
@@ -233,20 +233,19 @@ Router.prototype.handle = function handle(req, res, callback) {
 
     // find next matching layer
     var layer
-    var match
+    var match = false
     var route
 
-    while (match !== true && idx < stack.length) {
+    while (match === false && idx < stack.length) {
       layer = stack[idx++]
-      match = matchLayer(layer, path)
-      route = layer.route
-
-      if (typeof match !== 'boolean') {
-        // hold on to layerError
-        layerError = layerError || match
+      try {
+        match = layer.match(path)
+      } catch (err) {
+        layerError = layerError || err
       }
+      route = layer.route
 
-      if (match !== true) {
+      if (match === false) {
         continue
       }
 
@@ -277,7 +276,7 @@ Router.prototype.handle = function handle(req, res, callback) {
     }
 
     // no match
-    if (match !== true) {
+    if (match === false) {
       return done(layerError)
     }
 
@@ -288,9 +287,9 @@ Router.prototype.handle = function handle(req, res, callback) {
 
     // Capture one-time layer values
     req.params = self.mergeParams
-      ? mergeParams(layer.params, parentParams)
-      : layer.params
-    var layerPath = layer.path
+      ? mergeParams(match.params, parentParams)
+      : match.params
+    var layerPath = match.path
 
     // this should be done for the layer
     self.process_params(layer, paramcalled, req, res, function (err) {
@@ -603,22 +602,6 @@ function getProtohost(url) {
     : undefined
 }
 
-/**
- * Match path to a layer.
- *
- * @param {Layer} layer
- * @param {string} path
- * @private
- */
-
-function matchLayer(layer, path) {
-  try {
-    return layer.match(path)
-  } catch (err) {
-    return err
-  }
-}
-
 /**
  * Merge params with parent params
  *
diff --git a/lib/layer.js b/lib/layer.js
index 430f595..9f53df5 100644
--- a/lib/layer.js
+++ b/lib/layer.js
@@ -38,8 +38,6 @@ function Layer(path, options, fn) {
 
   this.handle = fn
   this.name = fn.name || '<anonymous>'
-  this.params = undefined
-  this.path = undefined
   this.regexp = pathRegexp(path, this.keys = [], opts)
 
   // set fast path flags
@@ -111,16 +109,18 @@ Layer.prototype.match = function match(path) {
   if (path != null) {
     // fast path non-ending match for / (any path matches)
     if (this.regexp.fast_slash) {
-      this.params = {}
-      this.path = ''
-      return true
+      return {
+        path: '',
+        params: {}
+      }
     }
 
     // fast path for * (everything matched in a param)
     if (this.regexp.fast_star) {
-      this.params = {'0': decode_param(path)}
-      this.path = path
-      return true
+      return {
+        path: path,
+        params: {'0': decode_param(path)}
+      }
     }
 
     // match the path
@@ -128,18 +128,12 @@ Layer.prototype.match = function match(path) {
   }
 
   if (!match) {
-    this.params = undefined
-    this.path = undefined
     return false
   }
 
-  // store values
-  this.params = {}
-  this.path = match[0]
-
   // iterate matches
   var keys = this.keys
-  var params = this.params
+  var params = {}
 
   for (var i = 1; i < match.length; i++) {
     var key = keys[i - 1]
@@ -151,7 +145,10 @@ Layer.prototype.match = function match(path) {
     }
   }
 
-  return true
+  return {
+    path: match[0],
+    params: params
+  }
 }
 
 /**
diff --git a/test/req.params.js b/test/req.params.js
index fc0e16c..70882a0 100644
--- a/test/req.params.js
+++ b/test/req.params.js
@@ -3,6 +3,7 @@ var Router = require('..')
 var utils = require('./support/utils')
 
 var createServer = utils.createServer
+var assert = utils.assert
 var request = utils.request
 
 describe('req.params', function () {
@@ -67,6 +68,27 @@ describe('req.params', function () {
       .expect(200, '{"foo":"bar"}', done)
   })
 
+  it('should not keep parameters in memory', function (done) {
+    var router = Router()
+    var server = createServer(function (req, res, next) {
+      router(req, res, function (err) {
+        if (err) return next(err)
+        sawParams(req, res)
+      })
+    })
+
+    router.get('/:fizz', hitParams(1))
+
+    request(server)
+      .get('/buzz')
+      .end(function(err) {
+        if (err) return done(err)
+
+        assert.strictEqual(router.stack[0].params, undefined)
+        done()
+      })
+  })
+
   describe('when "mergeParams: true"', function () {
     it('should merge outside object with params', function (done) {
       var router = Router({ mergeParams: true })