howhap-middleware
v4.1.3
Published
Easily integrate howhap errors into your express app.
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Houston, we have a problem - express middleware
A small library for displaying errors from express
npm install --save howhap
app.js
let express = require('express');
let howhap = require('howhap-middleware');
// An *optional* preset list of errors.
let options = {
errors: {
DEFAULT: {
message: 'An unknown error occurred.',
status: 500,
level: 'error' // this property specified what
// level of logging is associated
// with this error.
},
AUTH: {
INVALID_EMAIL: {
message: '{{ email }} is not a valid email.',
status: 400
},
MISSING_PASSWORD: {
message: 'Please enter a password.',
status: 400
}
}
},
defaultFormat: 'json', // If no response format is supplied,
// responses will be in this format.
logging: {
// options for winston loggin go here
}
};
let app = express();
// Pass in the option argument to customize the behavior
// of the middleware. Alternatively you can pass in nothing
// and use the default behavior.
app.use(howhap(options));
example route
let express = require('express');
let router = express.Router();
let validator = require('validator');
router.post('/login', function(req, res, next) {
let minPasswordLength = 8;
// You can call a preset error by using dot notation to
// traverse the predefined object and pass in parameters
// as the second argument. Errors are keyed by any string
// for later use. In this case 'email'.
if(!validator.isEmail(req.body.email)) {
res.error.add('AUTH.INVALID_EMAIL', {email: req.body.email}, 'email');
}
// Parameters are not required. Nor is the error key,
// which will be 'default' if none is specified.
if(!req.body.password) {
res.error.add('AUTH.MISSING_PASSWORD');
}
// You can also add custom error messages on the fly.
// Parameters can be specified in one object or passed
// in as a second argument like in the email example.
else if(req.body.password.length < minPasswordLength) {
res.error.add({
message: 'Your password must be at least {{ num }} chars long.',
status: 400,
params: {
num: minPasswordLength
}
}, 'password');
}
// Other code goes here...
// Send the errors and redirect back to the login page.
// If no argument is passed to the first argument of the
// send method then you will redirect back to the referer.
// The send method will return false if there are no errors
// to send. The send method takes a optional second argument
// specifying the response format you would like ('html' or
// 'json'). The format will be resolved in the following
// order:
//
// 1. The second argument of res.error.send
// 2. If (1) not specified then the responseFormat query
// parameter
// 3. If (2) not specified then the defaultFormat middleware
// option
// 4. If (3) not specified then 'json'
//
// If the resolved format is 'html' the user will be
// redirected to the specified redirect. Otherwise json will
// be returned.
if(!res.error.send('/login', 'html')) {
// There were no errors, redirect.
res.redirect('/dashboard');
}
// Here's an example of sending json
//
// if(!res.error.send(null, 'json')) {
// res.json(user);
// }
});example view
<!DOCTYPE html>
<html>
<head>
<title>Log in</title>
<link rel='stylesheet' href='/styles/main.scss.css' />
</head>
<body>
<h1>Log in</h1>
<form action="/auth/login" method="post">
<div>
<!--
- An `error` object is passed to all views, with a
- display method. The first argument is the key
- of the error that you'd like to display. The
- second (optional) argument is a default value
- that you'd like to display if there is no error
- for the specified key.
-->
<%= error.display('email') %>
<!--
- A `prev` object is also passed to all views,
- which stores the previous data that was posted
- (body, query, and params). This data is only set
- if there was an error. It takes two arguments
- (the type of data and the key) as well as an
- optional third argument if there was no data
- found for that particular key.
-->
<input type="email" placeholder="email" name="email" value="<%= prev.display('body', 'email') %>">
</div>
<div>
<!-- Example of using the optional default (second argument) -->
<%= error.display('email', 'Bad password') %>
<input type="password" placeholder="password" name="password">
</div>
<button>Log in</button>
</form>
</body>
</html>