File Attachments

[NfNitLoop]

Users should be able to attach files to a post. This would make sharing images, PDFs, etc. possible.

Rough plans are:

• Implement a content-addressable store.
• Re-use whatever hash-algorithm NaCL signatures currently use, since we're already using it.
• File names, hashes & sizes are stored within the protobuf.
• Standard URL sub-directory where files live.
• File uploads to the file names can be performed by anyone.
• File attachment quotas may disallow attaching large files.

Additional work:

• Update the client to know how to sync file attachments along with their Items.

[NfNitLoop]

Do I need to allow for future hash algorithms? Hmm, I guess Protobuf does this for me. I could have a

message File {
    bytes foo_hash = 1
    // ...
}

which just gets deprecated for a new one later.

[NfNitLoop]

File attachments are now available in v0.3.0. 🎉