Mumbling about computers

Patching over Backblaze's B2 lack of CORS

I've been trying to move our video content from youtube to our own server, but keeping in mind that we add about ~40GB / Month to our collection (and it never goes away..) and that DigitalOcean's disks are not very cheap, I decided to serve our videos directly from Backblaze.

Currently there's no CORS support on B2 ( https://help.backblaze.com/hc/en-us/articles/114094192774-Does-B2-have-CORS-headers-support- )

Backblaze recommends using Cloudflare as an SSL termination endpoint ( https://help.backblaze.com/hc/en-us/articles/217666928-Creating-a-Vanity-URL-with-B2 ) and using them as DNS to host stuff on your own domain. We'd rather not use Cloudflare.

So I ended up setting up a reverse caching proxy between B2 and my service:

nginx.conf:

proxy_cache_path /var/nginx-cache levels=1:2 keys_zone=my_cache:10m max_size=15g inactive=48h max_size=10g use_temp_path=off;

...

    location /cdn/ {
        proxy_set_header X-Real-IP  $remote_addr;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_buffers 16 4k; 
        proxy_buffer_size 2k; 

        proxy_cache my_cache;
        proxy_cache_revalidate on; 
        proxy_cache_min_uses 1;
        proxy_cache_lock on; 
        proxy_ignore_headers Cache-Control;
        add_header X-Cache-Status $upstream_cache_status;
        proxy_cache_valid any 48h;

        proxy_pass https://f001.backblazeb2.com/my-endpoint/;
    } 

Which works pretty nicely and even reduces part of the latency from B2. Considering this is hosted on a $5 DigitalOcean VPS and I get 1TB of traffic per month for free (which is below our current traffic) I end up saving money from B2.