ladjs/koa-better-error-handler

Name: koa-better-error-handler

Owner: Lad

Description: A better error-handler for Lad and Koa. Makes `ctx.throw` awesome (best used with koa-404-handler)

Created: 2016-07-24 09:42:04.0

Updated: 2018-05-20 15:59:49.0

Pushed: 2018-01-01 02:50:13.0

Homepage: https://lad.js.org

Size: 250

Language: JavaScript

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README

koa-better-error-handler

A better error-handler for Lad and Koa. Makes ctx.throw awesome (best used with koa-404-handler)

Index

• Features
• Install
• Usage
• API
• Web App
• User-Friendly Responses
• HTML Error Lists
• License

Features

• Uses Boom for making error messages beautiful (see User Friendly Responses below)
• Simply a better error handler (doesn't remove all headers like the built-in one does)
• Doesn't make all status codes 500 (like the built-in Koa error handler does)
• Supports Flash messages and preservation of newly set session object
• Fixes annoying redirect issue where flash messages were lost upon an error being thrown
• Supports HTML Error Lists using <ul> for Mongoose validation errors with more than one message
• Makes ctx.throw beautiful messages (e.g. ctx.throw(404) will output a beautiful error object :hibiscus:)
• Supports text/html, application/json, and text response types
• Supports and recommends use of mongoose-beautiful-unique-validation

Install

install --save koa-better-error-handler

Usage

You should probably be using this in combination with koa-404-handler too!

API

No support for sessions, cookies, or flash messaging:

t errorHandler = require('koa-better-error-handler');
t Koa = require('koa');
t Router = require('koa-router');
t koa404Handler = require('koa-404-handler');

nitialize our app
t app = new Koa();

verride koa's undocumented error handler
context.onerror = errorHandler;

pecify that this is our api
context.api = true;

se koa-404-handler
use(koa404Handler);

et up some routes
t router = new Router();

hrow an error anywhere you want!
er.get('/404', ctx => ctx.throw(404));
er.get('/500', ctx => ctx.throw(500));

nitialize routes on the app
use(router.routes());

tart the server
listen(3000);
ole.log('listening on port 3000');

Web App

Built-in support for sessions, cookies, and flash messaging:

t errorHandler = require('koa-better-error-handler');
t Koa = require('koa');
t redis = require('redis');
t RedisStore = require('koa-redis');
t session = require('koa-generic-session');
t flash = require('koa-connect-flash');
t convert = require('koa-convert');
t Router = require('koa-router');
t koa404Handler = require('koa-404-handler');

nitialize our app
t app = new Koa();

efine keys used for signing cookies
keys = ['foo', 'bar'];

nitialize redis store
t redisClient = redis.createClient();
sClient.on('connect', () => app.emit('log', 'info', 'redis connected'));
sClient.on('error', err => app.emit('error', err));

efine our storage
t redisStore = new RedisStore({
ient: redisClient


dd sessions to our app
use(
nvert(
session({
  store: redisStore
})



dd support for flash messages (e.g. `req.flash('error', 'Oops!')`)
use(convert(flash()));

verride koa's undocumented error handler
context.onerror = errorHandler;

se koa-404-handler
use(koa404Handler);

et up some routes
t router = new Router();

hrow an error anywhere you want!
er.get('/404', ctx => ctx.throw(404));
er.get('/500', ctx => ctx.throw(500));

nitialize routes on the app
use(router.routes());

tart the server
listen(3000);
ole.log('listening on port 3000');

User-Friendly Responses

Example Request:

 -H "Accept: application/json" http://localhost/some-page-does-not-exist

Example Response:

tatusCode": 404,
rror": "Not Found",
essage":"Not Found"

HTML Error Lists

If you specify app.context.api = true or set ctx.api = true, and if a Mongoose validation error message occurs that has more than one message (e.g. multiple fields were invalid) ? then err.message will be joined by a comma instead of by <li>.

Therefore if you DO want your API error messages to return HTML formatted error lists for Mongoose validation, then set app.context.api = false, ctx.api = false, or simply make sure to not set them before using this error handler.

With error lists:

tatusCode": 400,
rror": "Bad Request",
essage": "<ul class=\"text-xs-left mb-0\"><li>Path `company_logo` is required.</li><li>Gig description must be 100-300 characters.</li></ul>"

Without error lists:

tatusCode":400,
rror":"Bad Request",
essage":"Path `company_logo` is required., Gig description must be 100-300 characters."

License

MIT © Nick Baugh