Merge pull request #9 from jkyberneees/improve-error-handling

Improve error handling

Author: jkyberneees

README.md

@@ -68,9 +68,26 @@ server.listen(3000)
   }
   ```
 - **cacheSize**: Router matching LRU cache size. Default value: `1000`
+- **errorHandler**: Global error handler function. Default value: 
+  ```js 
+  (err, req, res) => {
+    res.statusCode = 500
+    res.end(err.message)
+  }
+  ```
+
+Example passing configuration options:
+```js
+const sequential = require('0http/lib/router/sequential')
+const { router, server } = cero({
+  router: sequential({
+    cacheSize: 2000
+  })
+})
+```
 
 #### Async middlewares
-You can user async middlewares to await the remaining chain execution. Let's describe with a custom error handler middleware:
+You can use async middlewares to await the remaining chain execution. Let's describe with a custom error handler middleware:
 ```js
 router.use('/', async (req, res, next) => {
   try {

demos/error-handling.js

@@ -1,16 +1,20 @@
 const sequential = require('../lib/router/sequential')
 const cero = require('../index')
 
+const errorHandler = (err, req, res) => {
+  res.statusCode = 500
+  res.end(err.message)
+}
 const { router, server } = cero({
-  router: sequential()
+  router: sequential(),
+  errorHandler
 })
 
 router.use('/', async (req, res, next) => {
   try {
     await next()
   } catch (err) {
-    res.statusCode = 500
-    res.end('Error Handler: ' + err.message)
+    errorHandler(err, req, res)
   }
 })
 
@@ -22,6 +26,12 @@ router.get('/err2', (req, res, next) => {
   next(new Error('Uuuups!'))
 })
 
+router.get('/err3', async (req, res, next) => {
+  setTimeout(() => {
+    next(new Error('Uuuups!'))
+  }, 50)
+})
+
 router.get('/async-err', async (req, res, next) => {
   throw new Error('Uuuups!')
 })

lib/next.js

@@ -1,4 +1,4 @@
-function next (middlewares, req, res, index, routerPatterns = {}, defaultRoute) {
+function next (middlewares, req, res, index, routerPatterns = {}, defaultRoute, errorHandler) {
   const middleware = middlewares[index]
   if (!middleware) {
     if (!res.finished) {
@@ -9,20 +9,24 @@ function next (middlewares, req, res, index, routerPatterns = {}, defaultRoute)
   }
 
   function step (err) {
-    if (err) throw err
-    return next(middlewares, req, res, ++index, routerPatterns, defaultRoute)
+    if (err) errorHandler(err, req, res)
+    return next(middlewares, req, res, ++index, routerPatterns, defaultRoute, errorHandler)
   }
 
-  if (middleware.id) {
+  try {
+    if (middleware.id) {
     // nested routes support
-    const pattern = routerPatterns[middleware.id]
-    if (pattern) {
-      req.preRouterUrl = req.url
-      req.url = req.url.replace(pattern, '')
+      const pattern = routerPatterns[middleware.id]
+      if (pattern) {
+        req.preRouterUrl = req.url
+        req.url = req.url.replace(pattern, '')
+      }
+      middleware.lookup(req, res, step)
+    } else {
+      return middleware(req, res, step)
     }
-    middleware.lookup(req, res, step)
-  } else {
-    return middleware(req, res, step)
+  } catch (err) {
+    errorHandler(err, req, res)
   }
 }
 

lib/router/sequential.js

@@ -7,6 +7,10 @@ module.exports = (config = {}) => {
     res.statusCode = 404
     res.end()
   })
+  config.errorHandler = config.errorHandler || ((err, req, res) => {
+    res.statusCode = 500
+    res.end(err.message)
+  })
   config.cacheSize = config.cacheSize || 1000
   config.id = config.id || (Date.now().toString(36) + Math.random().toString(36).substr(2, 5)).toUpperCase()
 
@@ -63,7 +67,7 @@ module.exports = (config = {}) => {
 
       // middlewares invocation
       req.params = Object.assign(req.params || {}, match.params)
-      next(middlewares, req, res, 0, routersPattern, config.defaultRoute)
+      next(middlewares, req, res, 0, routersPattern, config.defaultRoute, config.errorHandler)
     } else {
       config.defaultRoute(req, res)
     }

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "0http",
-  "version": "2.1.0",
+  "version": "2.2.0",
   "description": "Cero friction HTTP request router. The need for speed!",
   "main": "index.js",
   "scripts": {