cidsum bin?

[kallisti5]

Given you need an IPFS server to generate checksums of files currently, it seems like a cidsum or ipldsum binary to quickly generate the CID hash for files would be a handy tool to provide from rust-cid.

[kallisti5]

Hm. While rust-cid looks to work as expected for something like this, it's missing the "Protobuf UnixFS" content. I'm assuming this is the "Codec"?

[kallisti5]

use cid::Cid;
use multihash::{Code, MultihashDigest};
use std::env;

fn main() {
        let args: Vec<String> = env::args().collect();
        if args.len() != 2 {
                println!("usage: cidsum <file>");
                std::process::exit(1);
        }

        let data = match std::fs::read(&args[1]) {
                Ok(d) => d,
                Err(x) => {
                        println!("error: {:?}", x);
                        std::process::exit(1);
                }
        };

        let h = Code::Sha2_256.digest(&data);
        let cid = Cid::new_v0(h).unwrap();

        let cid_string = cid.to_string();
        println!("{}", cid_string);
}

This obviously wouldn't work well with large files, it needs some chunking for the sha256 checksum.

[dvc94ch]

Size of blocks is limited. You should check if the file size doesn't exceed 1mb. In addition you should use the raw codec 0x55 as this isn't protobuf.

[vmx]

@kallisti5 Do I understand correctly that you would want to have a tool that gets the same CID as IPFS would produce?

If yes, that's out of scope for rust-cid. You would need a full UnixFSv1 implementation to determine the CID. Such a tool is closer related to IPFS implementations.

[kallisti5]

Correct, that's the end goal. If protocol buffers are required, it indeed sounds like an external project would be more ideal.

[eighthave]

It seems that https://gitlab.com/NukeManDan/rust_cid_npm aims to provide something like cidsum