mirror of
https://github.com/namibia/awesome-cheatsheets.git
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226 lines
7.4 KiB
JavaScript
226 lines
7.4 KiB
JavaScript
/* *******************************************************************************************
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* API
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* http://expressjs.com/en/api.html
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* ******************************************************************************************* */
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`npm i express --save` or`yarn add -D express``(-D saves it as a dev dependency)`
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`yarn add -D @types/express``(Installing for TS)`
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const express = require("express"); // Importing the express library.
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const app = express(); // Intializing the imported express application
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/* *******************************************************************************************
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* GLOBAL OBJECTS
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* http://expressjs.com/en/api.html#express.json
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* ******************************************************************************************* */
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```Methods```;
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`express.json([options]);`
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options: `
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inflate // to manage the deflated bodies like enabling and disabling
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limit // Controls the maximum request body size.
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reviver // It is passed directly to JSON.parse as an second argument
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type // This is used to determine the type of middleware will parse
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verify // It is an undefined function which used to verify the middleware parsing.
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`;
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`express.raw([options]);`
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options: `
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inflate // to manage the deflated bodies like enabling and disabling
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limit // Controls the maximum request body size.
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type // This is used to determine the type of middleware will parse
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verify // It is an undefined function which used to verify the middleware parsing.
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`;
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`express.Router([options]);`
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options: `
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caseSensitive //Enables case sensitivity
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mergeParams //if param names of child and parent are conflicted then the child takes the precedence
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strict // Enables Strict routing
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`;
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`express.static(root, [options]);`
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options: `
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dotfiles // determines how dotfiles are used
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etag // Operates etag generation
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extensions // Operates file extension fallback
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fallthrough // Enable or disable the immutable directive in the Cache-Control response header
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index // sends the specified directory index file
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LastModified // sets the Last-Modified header to the last modified date
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setHeaders // Function for setting HTTP headers to serve with the file
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`;
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`express.text([options]);`
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options: `
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defaultCharset // Sets the default charset for the text context.
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inflate // to manage the deflated bodies like enabling and disabling
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limit // Controls the maximum request body size.
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type // This is used to determine the type of middleware will parse
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verify // It is an undefined function which used to verify the middleware parsing.
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`;
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`express.urlencoded([options]);`
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options: `
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extended // it allows to choose between parsing the URL-encoded data or the qs library
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parameterLimit // It controls the no of params.
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inflate // to manage the deflated bodies like enabling and disabling
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limit // Controls the maximum request body size.
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type // This is used to determine the type of middleware will parse
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verify // It is an undefined function which used to verify the middleware parsing.
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`;
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```Application`````;
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Properties```app.local`;
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`app.locals.title = "My Cheatsheet";
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console.dir(app.locals.title)`; `// Creating objects with local variables`
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app.mountpath`
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``app.mountpath``const admin = express()
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admin.get('/', function(req,res){
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console.log(admin.mountpath)
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res.send('Admin Homepage')
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})
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app.use('<admin dir>', admin)`; `// Mounting a sub - app`
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``Event``
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`admin.on('mount', (parent){
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console.log('Admin Mounted')
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})` `// Mounting on a parent app`
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``Methods``
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`app.get('/', function(req, res){
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res.send('GET request to message')
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})` `// get requests to the specified path`
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`app.post('/', function(req,res){
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res.send('POST request to a webpage')
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})` `// post request to the specified path`
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`app.put('/', function(req,res){
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res.send('PUT request to a webpage')
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})` `// post request to the specified path`
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`app.delete('/', function(req,res){
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res.send('DELETE request to a webpage')
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})` `// delete request to the specified path`
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`app.all('/', function(req,res,next){
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console.log('Accessing the secret section....')
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next()
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})` `// Routing all types of HTTP request`
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`app.param('user', function(req,res,next){
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User.find(id, function(err, user){
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if(err){
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next(err)
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} else if (user){
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req.user = user
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next()
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} else {
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next(new Error('Failed to load user'))
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}
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})
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})` `// Adding callback trigger to route parameters`
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`app.use(function(req,res,next){
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res.send('Hey There!')
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})` `// To Invoke the middleware layer that you want to add`
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```Request```
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``Methods``
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`req.get('content-type')` `// Returns the specified HTTP req header`
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`req.accepts('html')` `// Checks if the specified content types are available or not`
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`req.is('json')` `// Requests the matching content-type`
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`var range = req.range(1000)
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if (range.type === 'bytes'){
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range.forEach(function(r){
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// Your code
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})
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}` `// Range header parser`
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``Properties``
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`req.param('name')` `// Requests the param name when present`
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`app.post('/', function (req, res, next) {
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console.log(req.body)
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res.json(req.body)
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})` `// Data submitted in the request body`
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`console.dir(req.cookies.name)` `// Contains cookies sent by the request`
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`console.dir(req.query.q)` `// Query string parameter in the route`
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`console.log(req.route)
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res.send('GET')` `// Outputs all the layer, methods, path`
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`console.dir(req.signedCookies.user)` `// Logs all the signed cookies sent by the request`
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```Response```
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``Methods``
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`res.redirect('https://google.com')` `// Redirects to the intended page`
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`res.send({message: 'Awesome Stuffs'})` `// Response to the webpage`
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`res.json({alert: 'awesomecheatsheets'})` `// Response in JSON type`
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`const file = req.params.name;
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res.sendFile(file, options, function(err){
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if(err){
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next(err)
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}else{
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console.log('Sent:', file)
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}
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})` `// Sends file to the intended path`
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`res.render('index')` `// Rendering the intended file`
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```BodyParser```
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`const BodyParser = require('body-parser')
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app.use(BodyParser.json())
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app.use(BodyParser.urlencoded({
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extended: true
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}))` `// Parses incoming request bodies` |