ipfs.dag.get error

[longren610]

Regarding the BUG in ipfs.dag.get, the sample code in the ipfs.dag.get part of https://github.com/ipfs/js-ipfs/blob/master/docs/core-api/DAG.md cannot be run normally.

The following code can run normally and get the hash value: bafyreicyer3d34cutdzlsbe2nqu5ye62mesuhwkcnl2ypdwpccrsecfmjq

const { create } = require('ipfs-http-client')
const CID = require('cids');

const ipfs = create({ host: '127.0.0.1', port: '5001', protocol: 'http' })

var cid = async function(obj) {
    return await ipfs.dag.put(obj, { format: 'dag-cbor', hashAlg: 'sha2-256' });
}

const obj = {
  a: 1,
  b: [1, 2, 3],
  c: {
    ca: [5, 6, 7],
    cb: 'foo'
  }
}

cid(obj).then((ret) => {
  console.log(ret.toString())
});

Then use the hash value obtained and use the code in the example to get the data, and an error will be reported: No codec found for "undefined".code show as below:

const { create } = require('ipfs-http-client')
const CID = require('cids');

const ipfs = create({ host: '127.0.0.1', port: '5001', protocol: 'http' })

async function getAndLog(cid, path) {
  const result = await ipfs.dag.get(cid, { path:path })
}

getAndLog('bafyreicyer3d34cutdzlsbe2nqu5ye62mesuhwkcnl2ypdwpccrsecfmjq', '/a').then((ret) => {
  console.log(ret)
});

I tried several times and found that it was a cid problem. After modifying the code, I tried to run again, no more errors were reported, but the output value is always: undefined.code show as below:

const { create } = require('ipfs-http-client')
const CID = require('cids');

const ipfs = create({ host: '127.0.0.1', port: '5001', protocol: 'http' })

async function getAndLog(cid, path) {
  const result = await ipfs.dag.get(new CID(cid), { path:path })
}

getAndLog('bafyreicyer3d34cutdzlsbe2nqu5ye62mesuhwkcnl2ypdwpccrsecfmjq', 'a').then((ret) => {
  console.log(ret)
});

Use the cli command directly to obtain the data, and the data can be obtained normally.

Why is this so?

[welcome]

Thank you for submitting your first issue to this repository! A maintainer will be here shortly to triage and review.
In the meantime, please double-check that you have provided all the necessary information to make this process easy! Any information that can help save additional round trips is useful! We currently aim to give initial feedback within two business days. If this does not happen, feel free to leave a comment.
Please keep an eye on how this issue will be labeled, as labels give an overview of priorities, assignments and additional actions requested by the maintainers:

• "Priority" labels will show how urgent this is for the team.
• "Status" labels will show if this is ready to be worked on, blocked, or in progress.
• "Need" labels will indicate if additional input or analysis is required.

Finally, remember to use https://discuss.ipfs.io if you just need general support.

[achingbrain]

The cids module is deprecated, please use the CID class exported by the multiformats module:

const { create } = require('ipfs-http-client')
const { CID } = require('multiformats/cid');

const ipfs = create({ host: '127.0.0.1', port: '5001', protocol: 'http' })

async function getAndLog(cid, path) {
  const result = await ipfs.dag.get(CID.parse(cid), { path })
}

getAndLog('bafyreicyer3d34cutdzlsbe2nqu5ye62mesuhwkcnl2ypdwpccrsecfmjq', 'a').then((ret) => {
  console.log(ret)
});

[longren610]

The cids module is deprecated, please use the CID class exported by the multiformats module:

const { create } = require('ipfs-http-client')
const { CID } = require('multiformats/cid');

const ipfs = create({ host: '127.0.0.1', port: '5001', protocol: 'http' })

async function getAndLog(cid, path) {
  const result = await ipfs.dag.get(CID.parse(cid), { path })
}

getAndLog('bafyreicyer3d34cutdzlsbe2nqu5ye62mesuhwkcnl2ypdwpccrsecfmjq', 'a').then((ret) => {
  console.log(ret)
});

Thanks for the answer, the reason is found, there is no return value in the getAndLog function, so "undefined" is always printed. Sorry to bother you.

[longren610]

The reason is found, there is no return value in the getAndLog function, so "undefined" is always printed.