standard-http-error - npm explorer

StandardHttpError.js
====================
[![NPM version][npm-badge]](https://www.npmjs.com/package/standard-http-error)
[![Build status][travis-badge]](https://travis-ci.org/moll/js-standard-http-error)

StandardHttpError.js is a very simple but useful error class for
JavaScript and Node.js that represents HTTP errors. You can then detect it with
instanceof in error handling middleware and act accordingly. Also works in the
browser through Browserify.

You can use StandardHttpError.js with any error code you like, standardized or
not. They don't have to exist beforehand, so if you're living on the cutting
edge, feel free to use new HttpError(451, "Unavailable For Legal Reasons").

[npm-badge]: https://img.shields.io/npm/v/standard-http-error.svg
[travis-badge]: https://travis-ci.org/moll/js-standard-http-error.png?branch=master

Installing
----------
``sh npm install standard-http-error`

StandardHttpError.js follows semantic versioning, so feel free to depend on its major version with something like>= 1.0.0 < 2(a.k.a ^1.0.0).

Using -----`javascript var HttpError = require("standard-http-error") throw new HttpError(404)`

Your error handler will then receive an instance of HttpErroralong with the following enumerable properties:

Property | Value ---------|------ name |"HttpError"code |404message |"Not Found"

As always for errors, the non-enumerable stack property is there as well.

For compatibility with Express or Koa's default request handler (the one that prints your errors out if you don't handle them), StandardHttpError.js also setsstatus, statusCode and statusMessage to be aliases of codeandmessage. They're non-enumerable to not pollute serialization.

`$3`


StandardHttpError.js also supports passing a constant name instead of the error
code.

`javascript new HttpError("NOT_FOUND") new HttpError("FORBIDDEN")`

See below for a list of error code names.

`$3`

javascript
new HttpError(412, "Bad CSRF Token")


The default "Precondition Failed" message that the error code 412 would've
resulted in will then be replaced by "Bad CSRF Token".
Note that status messages were always meant to be human readable, so it's
perfect fine and even preferable to provide clarification in the status message.
Try to stick to the capitalized form, though, as that will match the default
HTTP status message style.
$3

You can pass custom properties to be attached to the error instance as an
object:

`javascript new HttpError(404, {url: req.url}) new HttpError(412, "Bad CSRF Token", {session: req.session})`

You can access the given session property then as err.session.

`$3`


If you wish to add your own functionality to StandardHttpError, subclass it:

`javascript var HttpError = require("standard-http-error")

function RemoteError(res) { HttpError.call(this, res.statusCode, res.statusMessage) }

RemoteError.prototype = Object.create(HttpError.prototype, { constructor: {value: RemoteError, configurable: true, writeable: true} })`

The StandardError.js library that StandardHttpError.js uses makes sure thename and stackproperties of your new error class are set properly.

If you don't want your new error class to directly inherit fromStandardHttpError, feel free to leave the RemoteError.prototypeline out. Everything will work as before except yourRemoteErrorwill no longer be aninstanceofStandardHttpError.js. You might want to manually grab theHttpError.prototype.toStringfunction then though, as that's useful for niceString(err) output.

`$3`

javascript
switch (err.code) {
  case HttpError.UNAUTHORIZED: return void res.redirect("/signin")
  case HttpError.NOT_FOUND: return void res.render("404")
  case 451: return void res.redirect("/legal")
  default: return void res.render("500")
}


$3

StandardHttpError.js comes very handy when used with Connect/Express's error
handling functionality:

`javascript var HttpError = require("standard-http-error") var app = require("express")()

app.get("/account", function(req, res, next) { if (req.account == null) throw new HttpError(401) if (req.account.budget == 0) throw new HttpError(402) // ... })

app.use(function(err, req, res, next) { if (!(err instanceof HttpError)) return void next(err)

res.statusCode = err.code res.statusMessage = err.message res.render("error", {title: err.message}) })`

Error Codes ----------- StandardHttpError.js comes with a list of status message constants that you can use for comparison and inswitch statements.

`javascript HttpError.NOT_FOUND // => 404`

When running on Node.js, cached status codes and their names get merged with new codes fromHttp.STATUS_CODES. Existing status codes will not be changed without bumping StandardHttpError.js's major version number. That ensures consistent constants in Node and in the browser.

Code | Name ------|-----100 | CONTINUE101 | SWITCHING_PROTOCOLS102 | PROCESSING200 | OK201 | CREATED202 | ACCEPTED203 | NON_AUTHORITATIVE_INFORMATION204 | NO_CONTENT205 | RESET_CONTENT206 | PARTIAL_CONTENT207 | MULTI_STATUS208 | ALREADY_REPORTED226 | IM_USED300 | MULTIPLE_CHOICES301 | MOVED_PERMANENTLY302 | FOUND303 | SEE_OTHER304 | NOT_MODIFIED305 | USE_PROXY307 | TEMPORARY_REDIRECT308 | PERMANENT_REDIRECT400 | BAD_REQUEST401 | UNAUTHORIZED402 | PAYMENT_REQUIRED403 | FORBIDDEN404 | NOT_FOUND405 | METHOD_NOT_ALLOWED406 | NOT_ACCEPTABLE407 | PROXY_AUTHENTICATION_REQUIRED408 | REQUEST_TIMEOUT409 | CONFLICT410 | GONE411 | LENGTH_REQUIRED412 | PRECONDITION_FAILED413 | PAYLOAD_TOO_LARGE414 | URI_TOO_LONG415 | UNSUPPORTED_MEDIA_TYPE416 | RANGE_NOT_SATISFIABLE417 | EXPECTATION_FAILED418 | IM_A_TEAPOT421 | MISDIRECTED_REQUEST422 | UNPROCESSABLE_ENTITY423 | LOCKED424 | FAILED_DEPENDENCY425 | UNORDERED_COLLECTION426 | UPGRADE_REQUIRED428 | PRECONDITION_REQUIRED429 | TOO_MANY_REQUESTS431 | REQUEST_HEADER_FIELDS_TOO_LARGE500 | INTERNAL_SERVER_ERROR501 | NOT_IMPLEMENTED502 | BAD_GATEWAY503 | SERVICE_UNAVAILABLE504 | GATEWAY_TIMEOUT505 | HTTP_VERSION_NOT_SUPPORTED506 | VARIANT_ALSO_NEGOTIATES507 | INSUFFICIENT_STORAGE508 | LOOP_DETECTED509 | BANDWIDTH_LIMIT_EXCEEDED510 | NOT_EXTENDED511 | NETWORK_AUTHENTICATION_REQUIRED

License ------- StandardHttpError.js is released under a *Lesser GNU Affero General Public License*, which in summary means:

- You can use this program for no cost. - You can use this program for both personal and commercial reasons. - You do not have to share your own program's code which uses this program. - You have to share modifications (e.g. bug-fixes) you've made to this program.

For more convoluted language, see the LICENSE` file.

About
-----
[Andri Möll][moll] typed this and the code.
[Monday Calendar][monday] supported the engineering work.

If you find StandardHttpError.js needs improving, please don't hesitate to type
to me now at [andri@dot.ee][email] or [create an issue online][issues].

[email]: mailto:andri@dot.ee
[issues]: https://github.com/moll/js-standard-http-error/issues
[moll]: http://themoll.com
[monday]: https://mondayapp.com

[npm-badge]: https://img.shields.io/npm/v/standard-http-error.svg
[travis-badge]: https://travis-ci.org/moll/js-standard-http-error.png?branch=master

Installing
----------
``sh npm install standard-http-error`

StandardHttpError.js follows semantic versioning, so feel free to depend on its major version with something like>= 1.0.0 < 2(a.k.a ^1.0.0).

Using -----`javascript var HttpError = require("standard-http-error") throw new HttpError(404)`

Your error handler will then receive an instance of HttpErroralong with the following enumerable properties:

Property | Value ---------|------ name |"HttpError"code |404message |"Not Found"

As always for errors, the non-enumerable stack property is there as well.

`$3`


StandardHttpError.js also supports passing a constant name instead of the error
code.

`javascript new HttpError("NOT_FOUND") new HttpError("FORBIDDEN")`

See below for a list of error code names.

`$3`

javascript
new HttpError(412, "Bad CSRF Token")


The default "Precondition Failed" message that the error code 412 would've
resulted in will then be replaced by "Bad CSRF Token".
Note that status messages were always meant to be human readable, so it's
perfect fine and even preferable to provide clarification in the status message.
Try to stick to the capitalized form, though, as that will match the default
HTTP status message style.
$3

You can pass custom properties to be attached to the error instance as an
object:

`javascript new HttpError(404, {url: req.url}) new HttpError(412, "Bad CSRF Token", {session: req.session})`

You can access the given session property then as err.session.

`$3`


If you wish to add your own functionality to StandardHttpError, subclass it:

`javascript var HttpError = require("standard-http-error")

function RemoteError(res) { HttpError.call(this, res.statusCode, res.statusMessage) }

RemoteError.prototype = Object.create(HttpError.prototype, { constructor: {value: RemoteError, configurable: true, writeable: true} })`

The StandardError.js library that StandardHttpError.js uses makes sure thename and stackproperties of your new error class are set properly.

`$3`

javascript
switch (err.code) {
  case HttpError.UNAUTHORIZED: return void res.redirect("/signin")
  case HttpError.NOT_FOUND: return void res.render("404")
  case 451: return void res.redirect("/legal")
  default: return void res.render("500")
}


$3

StandardHttpError.js comes very handy when used with Connect/Express's error
handling functionality:

`javascript var HttpError = require("standard-http-error") var app = require("express")()

app.get("/account", function(req, res, next) { if (req.account == null) throw new HttpError(401) if (req.account.budget == 0) throw new HttpError(402) // ... })

app.use(function(err, req, res, next) { if (!(err instanceof HttpError)) return void next(err)

res.statusCode = err.code res.statusMessage = err.message res.render("error", {title: err.message}) })`

Error Codes ----------- StandardHttpError.js comes with a list of status message constants that you can use for comparison and inswitch statements.

`javascript HttpError.NOT_FOUND // => 404`

License ------- StandardHttpError.js is released under a *Lesser GNU Affero General Public License*, which in summary means:

For more convoluted language, see the LICENSE` file.

About
-----
[Andri Möll][moll] typed this and the code.
[Monday Calendar][monday] supported the engineering work.

If you find StandardHttpError.js needs improving, please don't hesitate to type
to me now at [andri@dot.ee][email] or [create an issue online][issues].

[email]: mailto:andri@dot.ee
[issues]: https://github.com/moll/js-standard-http-error/issues
[moll]: http://themoll.com
[monday]: https://mondayapp.com