nextjs-exception-middleware

This middleware allows you to throw exceptions in your route handlers that are caught and returned as JSON.

For example,

``javascript
// Inside a route handler
if (bad_soups.includes(soup_param)) {
throw new BadRequestException({
type: "cant_make_soup",
message: "Soup was too difficult, please specify a different soup",
data: { soup_param }
})
}
`

will be returned as
`json
{
"error": {
"type": "cant_make_soup",
"message": "Soup was too difficult, please specify a different soup",
"data": {
"soup_param": "tomato"
}
}
}
`

with a status code of 400.

Installation

yarn add nextjs-exception-middleware or npm install nextjs-exception-middleware -s

Usage

Wrap your API handlers like so:

`javascript
import { withExceptionHandling } from "nextjs-exception-middleware"

export default withExceptionHandling({
// all parameters are optional
addOkStatus: false // add top-level "ok" status key to JSON responses
okStatusOptions: {
addIf: (req) => req.method === "GET" // only add "ok" status key if request is GET
},
exceptionHandlingOptions: {
getErrorContext: (req, errorContext) => {
// add any additional context to returned errors
errorContext.request_id = req.requestId
// delete error stack
delete errorContext.stack
return errorContext
}
}
})(async (req, res) => {
// ...
})
`

Exception Types

$3

Use HttpException to throw any HTTP exception providing the appropriate status code.

`javascript
import { HttpException } from "nextjs-exception-middleware"

export default (req, res) => {
/ ... /
throw new HttpException(403, {
type: "access_forbidden",
message: "No rights to access the content",
data: { client_id }
})
}
`

$3

Use BadRequestException to respond with 400 Bad Request status code.

`javascript
import { BadRequestException } from "nextjs-exception-middleware"

export default (req, res) => {
/ ... /
throw new BadRequestException({
type: "bad_request",
message: "Request cannot be processed due to malformed request syntax"
})
}
`

$3

Use UnauthorizedException to respond with 401 Unauthorized status code.

`javascript
import { UnauthorizedException } from "nextjs-exception-middleware"

export default (req, res) => {
/ ... /
throw new UnauthorizedException({
type: "unauthorized",
message: "Authenticate yourself to get the requested response",
data: { client_id }
})
}
`

$3

Use NotFoundException to respond with 404 Not Found status code.

`javascript
import { NotFoundException } from "nextjs-exception-middleware"

export default (req, res) => {
/ ... /
throw new NotFoundException({
type: "not_found",
message: "The requested resource not found",
data: { resource_id }
})
}
`

$3

Use MethodNotAllowedException to respond with 405 Method Not Allowed status code.

`javascript
import { MethodNotAllowedException } from "nextjs-exception-middleware"

export default (req, res) => {
/ ... /
throw new MethodNotAllowedException({
type: "method_not_allowed",
message: "Request method ${req.method} is not allowed"
})
}
`

$3

Use InternalServerErrorException to respond with 500 Internal Server Error status code.

`javascript
import { InternalServerErrorException } from "nextjs-exception-middleware"

export default (req, res) => {
/ ... /
throw new InternalServerErrorException({
type: "server_error",
message: "Internal server error occurred"
})
}
``