In the js-ipfs examples repository I found this piece of code showing how to assemble a merkle-tree or so called ‘dag’. const myData = { name: 'David', likes: ['js-ipfs', 'icecream', 'steak'] } ipfs.dag.put(myData, { format: 'dag-cbor', hashAlg: 'sha2-256' }, (err, cid) => { if (er…

If you’ve files, you’d normally would use the Files API . You can’t really put files into the DAG. You would read the file into a Buffer and store that. Please be aware that there is size limitations when you want to transfer the data to another peer (one DAG block can only be about 4MB).

Thank you for the reply. I tried to read through the specs, if I understand it correctly I have to upload the files to IPFS with the Files API and then construct a DAGnode with Object API… With this code I should be able to simply add an existing file to a DAGnode. The files that are used have firs…

I’m not sure why you want to operate on the DAG level. Why not using the File API to add the new file?

The structure of the Merkle DAG should enable me to access files by there name (just after the most up to date hash of the root), like: QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn/just-an-image (note: I understand this well, the root hash in my example is going to have another ‘updated’ hash: n…

[image] RenaPero: If I understand the files API correctly, it enables me to add a file to IPFS on itself, so not in a file structure (addressable by name, and within a directory) right? It’s kind of the other way round. The point of IPFS is to have a file/directory structures. If you look at …

So this file directory structure (with File API) is possible, but only with a single file right? So I can’t add multiple files to the same folder. Or don’t I understand this correctly?

You can add multiple files, see the Files API documentation for more information: https://github.com/ipfs/interface-ipfs-core/blob/8483084c89117d0f416e10761102f33ef1c948f9/SPEC/FILES.md#filesadd

Nice! I see add-readable-stream with an example , I wonder though how to get the hash of the root directory back. And is it possible in this code to put a file to the directory, by it’s hash (so when the file is already available on IPFS)? it('should add readable stream of valid files and dirs', fu…

I don’t know if there’s some direct way to get the root hash. But you could do a files.ls() in the root once the file is added.

an easy way to get the root hash : ipfs files stat /

How to create a hash linked Merkle tree_ IPLD dag in jsIPFS

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RenaPero February 15, 2021, 3:49pm 12

This is the answer I found working for this issue:

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How to create a hash linked Merkle tree_ IPLD dag in jsIPFS

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