How to fetch the Preview Image of a Stream

AlanRynne · 3 September 2021 09:11

Wow this is cool! I’m not the most knowledgeable person to answer this (@cristi or @dimitrie, please correct me if I’m wrong) but here it goes:

The preview service is run as a separate module from the server. You can get the preview image for any stream like this one https://speckle.xyz/streams/81d2f2c135 using the /preview/STREAM_ID url:

https://speckle.xyz/preview/81d2f2c135

I’m fairly certain the route structure is the same as for the stream url. So just replacing streams for preview should do the trick to get the image. See a specific branch preview:

https://speckle.xyz/preview/81d2f2c135/branches/info

As for how this actually works, as far as I’m aware it is configured through Nginx, which sends all /preview request to the server.

github.com

specklesystems/speckle-server/blob/eeadf103cbf9e4243cd4491de571d2cc420b2726/packages/frontend/nginx/nginx.conf#L35-L46

    
      
          location ~* ^/(graphql|explorer|(auth/.*)|(objects/.*)|(preview/.*)|(api/.*)) {
            resolver 127.0.0.11 valid=30s;
            set $upstream_speckle_server speckle-server;
            client_max_body_size 100m;
            proxy_pass http://$upstream_speckle_server:3000;
          
          
  proxy_buffering off;
            proxy_request_buffering off;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";
          }

Then the server interacts with the preview module to return your image:

And that’s as far as my knowledge can take you Looking forward to a demo of that cool app!