Make it work with Async Hooks

HISTORY.md

@@ -8,6 +8,7 @@ unreleased
     - deps: [email protected]
   * deps: [email protected]
   * deps: type-is@~1.6.18
+  * Make it work with Async Hooks
 
 1.19.0 / 2019-04-25
 ===================

lib/read.js

@@ -17,6 +17,12 @@ var iconv = require('iconv-lite')
 var onFinished = require('on-finished')
 var zlib = require('zlib')
 
+var asyncHooks
+try {
+  asyncHooks = require('async_hooks')
+} catch (ignored) {
+}
+
 /**
  * Module exports.
  */
@@ -74,7 +80,7 @@ function read (req, res, next, parse, debug, options) {
 
   // read body
   debug('read body')
-  getBody(stream, opts, function (error, body) {
+  getBody(stream, opts, preserveAsyncContext('GetBody', function (error, body) {
     if (error) {
       var _error
 
@@ -91,9 +97,9 @@ function read (req, res, next, parse, debug, options) {
 
       // read off entire request
       stream.resume()
-      onFinished(req, function onfinished () {
+      onFinished(req, preserveAsyncContext('OnFinished', function onfinished () {
         next(createError(400, _error))
-      })
+      }))
       return
     }
 
@@ -128,7 +134,7 @@ function read (req, res, next, parse, debug, options) {
     }
 
     next()
-  })
+  }))
 }
 
 /**
@@ -179,3 +185,11 @@ function contentstream (req, debug, inflate) {
 
   return stream
 }
+
+function preserveAsyncContext (asyncResourceType, fn) {
+  if (!asyncHooks) {
+    return fn
+  }
+  var asyncResource = new asyncHooks.AsyncResource(asyncResourceType)
+  return asyncResource.runInAsyncScope.bind(asyncResource, fn, null)
+}

test/body-parser.js

@@ -3,6 +3,13 @@ var http = require('http')
 var methods = require('methods')
 var request = require('supertest')
 
+var describeWhenAsyncHooksAreSupported = describe.skip
+try {
+  var asyncHooks = require('async_hooks')
+  describeWhenAsyncHooksAreSupported = typeof asyncHooks.AsyncLocalStorage === 'function' ? describe : describe.skip
+} catch (ignored) {
+}
+
 var bodyParser = require('..')
 
 describe('bodyParser()', function () {
@@ -51,6 +58,57 @@ describe('bodyParser()', function () {
       .expect(200, '{"user":"tobi"}', done)
   })
 
+  describeWhenAsyncHooksAreSupported('used with async hooks', function () {
+    it('should maintain context when parsing was successful', function (done) {
+      var _bodyParser = bodyParser()
+      var asyncLocalStorage = new asyncHooks.AsyncLocalStorage()
+
+      var server = http.createServer(function (req, res) {
+        const store = {
+          contextMaintained: true
+        }
+        asyncLocalStorage.run(store, function () {
+          _bodyParser(req, res, function (err) {
+            res.statusCode = err ? (err.status || 500) : 200
+            res.end(err ? err.message : JSON.stringify(asyncLocalStorage.getStore()))
+          })
+        })
+      })
+
+      request(server)
+        .post('/')
+        .set('Content-Type', 'application/json')
+        .send('{"user":"tobi"}')
+        .expect(200, '{"contextMaintained":true}', done)
+    })
+
+    it('should maintain context when parsing has failed', function (done) {
+      var _bodyParser = bodyParser.text()
+      var asyncLocalStorage = new asyncHooks.AsyncLocalStorage()
+
+      var server = http.createServer(function (req, res) {
+        const store = {
+          contextMaintained: true
+        }
+        asyncLocalStorage.run(store, function () {
+          _bodyParser(req, res, function (err) {
+            if (!err) {
+              res.statusCode = 500
+              res.end('parsing was expeced to fail, but it succeeded')
+            }
+            res.end(JSON.stringify(asyncLocalStorage.getStore()))
+          })
+        })
+      })
+
+      request(server)
+        .post('/')
+        .set('Content-Type', 'text/plain; charset=x-fake')
+        .send('user is tobi')
+        .expect(200, '{"contextMaintained":true}', done)
+    })
+  })
+
   describe('http methods', function () {
     before(function () {
       var _bodyParser = bodyParser()