JacobWay/express.md

## express.md

      
    Raw
  

              express.md
            
          
    Guide

Routing

Routing resfers to the definition of application end points (URIs) and how they response to client requests.
Routing methods


express class -> routing methods -> http methods

Routing paths


route path based on strings
route path based on string patterns
route path based on regular expressions

Route parameters

Route handlers

Response methods


response.download()
response.end()
response.json()
response.jsonp()
response.redirect()
response.render()
response.send()
response.sendFile()
response.sendStatus()

app.route()

express.Router

Use the express.Router class to create modular, mountable route handlers.
Writing middleware for use in Express apps

Overview

Middleware -> request, response, next
Middleware function can perform the following tasks:

Excute any code.
Make changes to the request and the response objects.
End the request-response cycle.
Call the next middleware in the stack.

Example

Configurable middleware

Refer to cookie-session and compression for examples of configurable middleware.
Using middleware

An Express web application is essentially a series of middleware function calls.
An Express application can use the following types of middleware.

Application level middleware
Router level middleware
Error handling level middleware
Building middleware
Third party middleware

Application level middleware


app.use([mounted path], <middleware function handler>)
app.httpMethod([mounted path], <middleware function handler>)

Router level middleware

Router level middleware is bound to an instance of express.Router().
Error handling middleware

Build in middleware

Third party middleware

Using template engines with Express

A template engine enables you to use static template files in your application.

app.set("views", "the directory of template files")
app.set("view engine", "the name of the view engine")

Error handling

Debugging Express

DEBUG=smaple-app,html,mail,express:* node index.js
Express behind proxies

Database integration