Score:2

Server

NGINX Redirect to Cached File in Subfolder

Timothy R. Butler

11/5/22, 5:11 PM

I have a program that creates optimized versions of pictures that are uploaded to the /images/ folder on the web server. It traverses subfolders and in each one, creates a .optimized folder that holds the optimized version, if it is at least a certain size smaller than the original. My goal is to check if such an optimized version exists, serve it if it does, and serve the original otherwise (in some sense like how gzip_static serves a .gz version of a file if it exists).

I'm running NGINX as a proxy in front of Apache, so while I'm accustomed to handling issues like this using htaccess, I am trying to do it natively in NGINX to avoid the server having to hand the request over to Apache. In .htaccess, I could do something like this:

RewriteCond %{REQUEST_FILENAME} ^(/images/(?:.*/)?)(.*?)$ [OR]
RewriteCond $1.optimized/$2 -f
RewriteRule .* $1/.optimized/$2 [L]

Is there a good way to handle this directly in NGINX? Most similar use cases I've found kept all the cached/optimized files in a single cached folder, as opposed to the structure I'm describing.

139

1 + 4

mod-rewrite

optimization

nginx

djdomi

11/5/22, 5:15 PM

`if ($request_filename ~ "^/(.*/)+(.*?)$"){ set $rule_0 1; } if (-f /${fref_0_0}/.optimized/${fref_0_1}){ set $rule_0 1; } if ($rule_0 = "1"){ rewrite /.* /$1/.optimized/$2 last; }` can you test this, if I read your request correctly it may work, else we have to use try files

Richard Smith

11/5/22, 5:17 PM

The files are below the `/images/` folder. Does the URI begin with `/images/` also?

Timothy R. Butler

11/5/22, 5:20 PM

@djdomi Thank you! I'll have access to my server in just a bit and will give that a try.

Timothy R. Butler

11/5/22, 5:20 PM

@RichardSmith Yes. I erroneously had left that out of the htaccess example. I corrected that now. Thanks!

Score:3

Server

Richard Smith

11/5/22, 5:27 PM

You can use a regular expression location to extract the first and second parts of the URI. Use a try_files statement to search the file system for each file in order.

For example:

location ~ ^(/images/.*?)([^/]+)$ {
    try_files $1.optimized/$2 $1$2 =404;
}

0 + 4

Tero Kilkanen

11/5/22, 7:22 PM

I think the order should be `try_files $1.optimized/$2 $1$2 =404`, so that the optimized version is used if it exists.

Richard Smith

11/5/22, 7:28 PM

Oops. Fixed. Thanks @TeroKilkanen

Timothy R. Butler

11/6/22, 4:44 AM

Thank you so much! There was a bug in my regex (it assumed there would be at least one subdirectory involved, which can't be assumed), although even when I switch to `^(/images/(?:.*/)?)(.*)$` it doesn't seem to be "activating." I'm trying to figure out why....

Timothy R. Butler

11/6/22, 7:51 AM

Oh! I realized that my proxy_pass was getting in the way of serving static content... I'll have to work on that, but that at least explains why it didn't apply. Thanks again!

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: NGINX Redirect to Cached File in Subfolder

TH: NGINX เปลี่ยนเส้นทางไปยังไฟล์แคชในโฟลเดอร์ย่อย

RO: Redirecționează NGINX către fișierul cache din subdosar

RU: Перенаправление NGINX на кэшированный файл в подпапке

VI: NGINX chuyển hướng đến tệp được lưu trong bộ nhớ cache trong thư mục con

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