multiblob-http

serve content-addressed blobs over http. see use with multiblob

example

var MultiBlob = require('multiblob')
var MultiBlobHttp = require('multiblob-http')
var http = require('http')

var dir = where_files_go //set this.

var blobs = MultiBlob(dir)

http.createServer(MultiBlobHttp(blobs, '/blobs')).listen(8000)

this will return an http handler (compatible with express middleware) that will handle requests

• GET /blobs/get/{id}
• POST /blobs/add (which will respond with the hash)

you can also set a different prefix, but I use /blobs

http api

GET /get/{id}

retrive blob with hash {id}

POST /add

posts to add do not require to have a hash, but will respond with the hash. (TODO: take a POST to /add/{id} and error if received content did not have that hash)

caching && headers

multiblobs-http provides the correct headers to make serving content-addressed files as efficient as possible.

First the the etag header is set to the hash and the expires header is set to a year in the future. Ideally, the browser shouldn't request this resource again for a whole year. Probably it might revalidate it when someone uses ctrl-R to reload the page. When it does, it will request with if-none-modified set to the hash. Since content-addressed files are never modified, the server immediately responds with 304 (not modified)

the content-length header is always used. This way, if a connection fails somehow, or there is an error later, the browser should detect it.

Of course, it would be way better if browsers just understood content-hashes. But, we have to play the hand we where delt, and multiblob-http makes the most of the broken web we live in.

License

MIT