An Express error handler/router than directs errors to the proper error page
An Express handler for handling errors and determining the view to show to the user.
- NodeJS 6 LTS
The general error handler will either send a message via JSON for AJAX calls or it will render an error page.
Errors can have a custom field, status, which defines which HTTP status code to use for that error.
If the status is not defined, a 500 status is assumed.
Suggest using Http-Errors to preset status.
Alternatively, when using Error, status may be set along with showView to define the specific template.
When the generic error handler is rendering a page, it may use fallback pages if the specified page does not exist.
The order the error handler will try is defined by:
- The template set in showView if set on the Error object
- Templates within any subdirectories up to the root views directory for:
- A template based on the status code
- A template based on the status code class (ex all 400-499 fall back to 4xx and 500-599 fall back to 5xx)
- A generic template used to catch all
- Just rendering the string out
Example code: 503 with showView set to "errors/oops" with the URL "blog/this-is-a-post"
- errors/oops.dust
- blog/errors/503.dust
- blog/errors/5xx.dust
- blog/errors/error.dust
- errors/503.dust
- errors/5xx.dust
- errors/error.dust
- No template, just send the string
For non-GET routes, the client will be redirected for non-XHR requests.
The clients by default will be redirected back to the previous page.
XHR clients will receive the error over JSON and will not be redirected.
401 redirects are special in that they can be redirected to a specific page by setting redirectOn401 in the options when initializing the error-router.
The redirect location can also be changed by setting either redirectTo on the error object being thrown or by settings errorRedirectTo on the Express req object for the specific request.