Redirect .php extension to WordPress if not exists

[jessuppi]

We should consider doing this, in case of websites that have a history of using various CMS and such, to avoid tons of 404 errors which are bad for SEO and usability.

Some reading:

https://stackoverflow.com/questions/38911354/nginx-php-file-extension-does-not-work-with-try-files

Side note, we should also organize our server blocks better per answers here.

[jessuppi]

I had thought this wasn't working correctly, but seems that it is working fine actually:

location ~* \.php$ {
    include /etc/nginx/fastcgi.conf;
    try_files $uri $uri/ /index.php?$args; ## send .php requests to WordPress if not found
...
}

Ref: https://serverfault.com/questions/901761/nginx-redirect-to-a-php-file-with-try-files-if-required-php-file-not-found

Ref: https://github.com/littlebizzy/slickstack/blob/master/modules/nginx/sites/production.txt

So I'm closing this for now.

[jessuppi]

It's still not working consistently. I discovered it's a conflict with FastCGI Cache rules, this snippet:

## blank session and strip cookie header if cached page ##
if ($skip_cache = 0 ) {
        set $ss_session "";
        more_clear_headers "Set-Cookie*";
}

...under the location ~* \.php$ { block. Disabling FastCGI Cache on a SlickStack server fixes it immediately...

[jessuppi]

I see GridPane skips FastCGI cache on .php files:

https://gridpane.com/kb/gridpane-default-cache-exclusions/

Thus, their similar redirect of non-existent .php files probably works more consistently:

https://gridpane.com/kb/redirects-with-non-existent-php-files/

[jessuppi]

It's a conflict between the if conditions and try_files ... not very well documented. I found these:

https://stackoverflow.com/questions/39548301/if-conditions-break-try-files-in-nginx-configuration

https://stackoverflow.com/questions/50318014/try-files-directive-being-ignored-when-used-with-fastcgi

https://serverfault.com/questions/579613/nginx-config-if-and-try-files