Express

Express

Middleware

• A function that has a (request, response, next) signature
• No return value, just calls next()
• Can make an anonymous function as middleware
• Middleware is executed in order
• Middleware processes until next() isn’t called, or an error is generated
• If you call next(error) with an argument, it will look for error handling middleware
• Error handling middleware has 4 arguments (error, request, response, next)
• If you need to pass values in, your middleware will be a factory that returns a function with the middleware signature

Express Middleware

• Used with app.use();
• app.use() will match all methods for all routes.
• Express methods are all chainable.

Useful Express middleware

• body-parser
• serve-static
• compression
• cookie-parser
• cookie-session
• express-session
• errorhandler
• passport
• morgan
• winston
• csurf
• serve-favicon
• method-override
• vhost

Using a templating engine

app.set(“views”, “templates”) // Template Folder
app.set(“view engine”, “jade”) // Engine you want to use

response.render(“template-name”, dataObject);