A function that returns the IPFS addresses of files without uploading them

[yxliang01]

This would be useful for many applications, especially for experiments.

[jbenet]

should be able to be done with ipfs add --only-hash (so ipfs.add({"only-hash": true}, ...) i think? cc @diasdavid @dignifiedquire

[daviddias]

Exactly, you can do that with the only-hash option.

[yxliang01]

Thanks. But, when I pass opts with the key only-hash to ipfs.util.addFromFs, this function never calls the callback.. Help needed.

[yxliang01]

By try and error and some analysis, I think has nothing deal with ipfs.util.addFromFs. If the file was uploaded before or run with ipfs add --only-hash before, ipfs.util.addFromFs calls the cb almost immediately. But, if the file was brand new to the IPFS, it just hanged without error. I tried to understand the source code, but I haven't really understood it yet...

[aakilfernandes]

@yxliang01 you can take a look at this for inspiration

https://github.com/SafeMarket/ux/blob/master/lib/utils/getUnixMultihash.js

I agree, this should be added as a utility function somewhere. Most devs (including myself) don't understand the difference between a multihash and an ipfs multihash

http://0kalmi.blogspot.com/2015/12/what-goes-into-ipfs-multihash.html

[yxliang01]

Thanks @aakilfernandes . While this is handy, I still think only-hash should work and do the job perfectly because it can guarantee that no matter how IPFS changes its way calculating the hash, the result is still accurate...

[yxliang01]

So... I think this is a bug instead of a question. Anyone has idea?

[yxliang01]

Okay, I think I know why. After dipping into the code, I found that add.js doesn't have options support which contradicts the documentation ipfs.files.add(data, [options], [callback]) at https://github.com/ipfs/interface-ipfs-core/tree/master/API/files#add .

[santiagorp]

What happens with this? I saw a branch containing a fix to this issue which was deleted today without merging...