How tornado captures and handles 404 errors

As mentioned in Tornado, only errors in path requests listed in handlers can be captured.

If only one rule (r "/hello", HelloHandler) is defined, only requests with undefined paths such as/hello/other can be captured, the default 404 error page of Tornado is displayed directly, such as/he,/helloworld, And/he/other, without displaying custom error pages.

The solution is simple. You only need to add one (r ". * ", BaseHandler) is used to capture all requests not captured by other rules, overwrite the get method, and call the custom write_error method in the method. Example:

Copy codeThe Code is as follows:
Class BaseHandler (tornado. web. RequestHandler ):
Def get (self ):
Self. write_error (404)

Def write_error (self, status_code, ** kwargs ):
If status_code = 404:
Self. render ('Public/404.html ')
Elif status_code = 500:
Self. render ('Public/500.html ')
Else:
Self. write ('error: '+ str (status_code ))