Question

I’m receiving attachments from postmarkapp (described here: http://developer.postmarkapp.com/developer-inbound-parse.html#attachments).

I want to upload those photos to facebook using fb_graph (https://github.com/nov/fb_graph) using its photo! method (https://github.com/nov/fb_graph/wiki/Photo-and-Album).

This is easy and works fine when testing by specifying a :source like in the examples from an actual file.

However I’m trying to not write out to a file but instead just convert the base64 encoded string to StringIO and pass that as the :source argument. This doesn’t work and I get this error:

ruby
FbGraph::InvalidRequest: OAuthException :: (#324) Requires upload file


The reason I don’t want to write out a file is because I’m using heroku and delayed_job so I’m not sure if a file I write out will still be around when the job is processed. That would be nice however since my current plan is to store the images in the db with delayed job.

Thanks.

Answer 1

I couldn’t find a way to make this work with heroku without first uploading it to mongohq with gridfs. You can’t use the cedar ephemeral file system because those files, written during a controller action, won’t be visible to your delayed_job worker.

So even though it sucks I do this;

1. Receive upload from postmarkapp (blocks one dyno)
2. Write to mongohq using grid fs (this involves one upload which blocks one dyno)
3. Queue job using delayed_job
4. Read back from mongohq (blocks one worker while downloading)
5. Re-upload to FB when posting

So why not just post directly to facebook if I’m going to incur that initial blocking cost of uploading to mongohq anyway? Because that upload is way faster than uploading to FB for reasons unkonwn.

The right answer on heroku is to have a node.js dyno handling these callbacks from postmark so the dyno isn’t blocked during either the read from postmark or the write to mongohq (or facebook) then to do some extra work to have the node app interact with the rails app to stay synced.