84 lines
2.4 KiB
Markdown
84 lines
2.4 KiB
Markdown
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---
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id: index
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title: Getting Started
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---
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express-validator is a set of [express.js](http://expressjs.com/) middlewares that wraps
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[validator.js](https://github.com/chriso/validator.js) validator and sanitizer functions.
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## Installation
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Install it using npm (make sure that you have Node.js 6 or newer):
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```
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npm install --save express-validator
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```
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## Basic guide
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> It's recommended that you have basic knowledge of the express.js module before you go on with
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this guide.
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Let's get started by writing a basic route to create a user in the database:
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```js
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const express = require('express');
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const app = express();
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app.use(express.json());
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app.post('/user', (req, res) => {
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User.create({
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username: req.body.username,
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password: req.body.password
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}).then(user => res.json(user));
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});
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```
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Then, you'll want to make sure that you validate the input and report any errors before creating the user:
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```js
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// ...rest of the initial code omitted for simplicity.
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const { body, validationResult } = require('express-validator');
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app.post('/user', [
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// username must be an email
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body('username').isEmail(),
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// password must be at least 5 chars long
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body('password').isLength({ min: 5 })
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], (req, res) => {
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// Finds the validation errors in this request and wraps them in an object with handy functions
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const errors = validationResult(req);
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if (!errors.isEmpty()) {
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return res.status(400).json({ errors: errors.array() });
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}
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User.create({
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username: req.body.username,
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password: req.body.password
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}).then(user => res.json(user));
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});
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```
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*Voila!* Now, whenever a request that includes invalid `username` or `password` fields
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is submitted, your server will respond like this:
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```json
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{
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"errors": [{
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"location": "body",
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"msg": "Invalid value",
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"param": "username"
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}]
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}
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```
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For all the available validators in express-validator (just like its options),
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take a look at validator.js docs [here](https://github.com/chriso/validator.js#validators).
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## What's next
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This completes the basic guide on getting started with express-validator.
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You might want to continue reading about some of the more advanced features available:
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- [Sanitization](feature-sanitization.md)
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- [Custom validators/sanitizers](feature-custom-validators-sanitizers.md)
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- [Custom error messages](feature-error-messages.md)
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- [Wildcards](feature-wildcards.md)
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- [Schema validation](feature-schema-validation.md)
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