CSRF tokens for Koa

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npm:

npm install koa-csrf

1. Add middleware in Koa app (default options are shown):

   const Koa = require('koa');
   const bodyParser = require('koa-bodyparser');
   const session = require('koa-generic-session');
   const convert = require('koa-convert');
   const CSRF = require('koa-csrf');
   
   const app = new Koa();
   
   // set the session keys
   app.keys = [ 'a', 'b' ];
   
   // add session support
   app.use(convert(session()));
   
   // add body parsing
   app.use(bodyParser());
   
   // add the CSRF middleware
   app.use(new CSRF({
     invalidTokenMessage: 'Invalid CSRF token',
     invalidTokenStatusCode: 403,
     excludedMethods: [ 'GET', 'HEAD', 'OPTIONS' ],
     disableQuery: false
   }));
   
   // your middleware here (e.g. parse a form submit)
   app.use((ctx, next) => {
     if (![ 'GET', 'POST' ].includes(ctx.method))
       return next();
     if (ctx.method === 'GET') {
       ctx.body = ctx.csrf;
       return;
     }
     ctx.body = 'OK';
   });
   
   app.listen();

2. Add the CSRF token in your template forms:

   Jade Template:

   form(action='/register', method='POST')
     input(type='hidden', name='_csrf', value=csrf)
     input(type='email', name='email', placeholder='Email')
     input(type='password', name='password', placeholder='Password')
     button(type='submit') Register

   EJS Template:

   <form action="/register" method="POST">
     <input type="hidden" name="_csrf" value="<%= csrf %>" />
     <input type="email" name="email" placeholder="Email" />
     <input type="password" name="password" placeholder="Password" />
     <button type="submit">Register</button>
   </form>

• invalidTokenMessage (String or Function) - defaults to Invalid CSRF token, but can also be a function that accepts one argument ctx (useful for i18n translation, e.g. using ctx.request.t('some message') via @ladjs/i18n
• invalidTokenStatusCode (Number) - defaults to 403
• excludedMethods (Array) - defaults to [ 'GET', 'HEAD', 'OPTIONS' ]
• disableQuery (Boolean) - defaults to false

• Existing methods from 1.x package added to 3.x
• Existing tests from 1.x package added to 3.x

MIT © Jonathan Ong