return custom error pages in nginx, flask

Question

I tried other answers in SO, like :

Return custom 403 error page with nginx

nginx + uwsgi + flask - disabling custom error pages

nginx not serving my error_page

and

references:

http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_intercept_errors

http://nginx.org/en/docs/http/ngx_http_core_module.html#error_page

but still not able to return custom error pages - nginx keeps to return its own pages.

Working in local env, flask returns custom html pages.

When published in nginx, no more.

This is what I want to have:

if user hit /js/, route will return 403, while allowing to internal files /js/myJS.js
If file /js/myJS.js does not exist, return 404
If something goes awry, say an API in flask that break (it shouldn't :) ) > return 500

My flask configuration is like:

@application.errorhandler(404)
def error_404(e):
    application.logger.error('Page Not Found: %s', (request.path))
    #return render_template('404.html'), 404
    return render_template("404.html", error = str(e)), 404

// other errors are handled similarly

and the 404.html template, is within var/www/mysite/templates folder.

The error page are static files, there are no assets served from flask but the html template.

Now, in my nginx configuration I am handling errors like this:

root var/www/mysite;
# update: tried to handle custom errors with proxy_intercept_errors on; 
# still no success
proxy_intercept_errors on;


# static is the directory that serve the subdirectory /js
# HOW COULD I RETURN 403 if /js is hit directly, but not /js/myfile.js ? 
# I tried to add deny all and allow only my server up, but did not worked out

location /static {
        expires 1M;
        alias /var/www/mysite/static;
        access_log off;
        add_header Cache-Control "public";
        allow #myserverip;
        deny all;
    }

    error_page 403 /403.html;
    location = /403.html {
        root /var/www/mysite/templates/;
        internal;
    }


    error_page 404 /404.html;
    location = /404.html {
        root /var/www/mysite/templates/;
        # internal;
        allow all;  
    }

    # also with the following no success: nginx white internal page is still displayed 
    error_page 404 http://example.com/404.html;

That I try to set internal or comment it out; that I try to set allow all (as in answer in above SO answer) , no matter what, nginx will return its custom page 404 - not from my templates folder.

I also tried to set up a folder for fallback, like:

## Fallback Directory
location @error {
    root /var/www/error;
}

but still no success - always the white 404 page from nginx.

What is wrong in my configuration ?

I would like to better understand how flask and nginx dialogue for errors.

I understood that once published, nginx will handle the error - but did not understood how the raised error are handled between flask and nginx: what happen when user hit route of a "wrong" resource ? is it nginx that intercept it? is it flask? is it uwsgi ? how do they pass the ball?

Also, please share a tip: how could I query error pages in nginx, e.g. for testing bad requests 403 and 500 ?

return custom error pages in nginx, flask

0 Answers0