CODEWITHSUNDEEP
javascriptimagehashipfs
Torof
Torof

Reputation: 237

How to create an ipfs hash from an image source?

I have the src (data) of an image, that is not saved yet and doesn't have a path yet. I would like to know the future ipfs hash that will result from it once it is saved and sent to ipfs.

So far I have done this, but the hashes don't match.

import { saveAs } from 'file-saver';
const dagPB = require('ipld-dag-pb')
const UnixFS = require('ipfs-unixfs')

func = async () => {   
    let bgImage = await import(`./images/bg.png`);
    let bodyImage = await import(`./images/body.png`);
    let headImage = await import(`./images/head.png`);
    let eyesImage = await import(`./images/eye.png`);
    let mouthImage = await import(`./images/mouth.png`);
    let levelImage = await import(`./images/level.png`);

    src = await mergeImages([
      bgImage.default,
      bodyImage.default,
      headImage.default,
      eyesImage.default,
      mouthImage.default,
      levelImage.default,
    ]);
    
    image.src = src;
    saveAs(image.src, `photo.png`);
    const fileBuffer = Buffer.from(image.src)
    const file = new UnixFS('file', fileBuffer)

    dagPB.DAGNode.create(file.marshal(), (err, node) => {
     if(err) return console.error(err)
     console.log(node._cid.toBaseEncodedString())
    })
}

What is missing or wrong ?

Upvotes: 2

Views: 1365

Answers (1)

Torof
Torof

Reputation: 237

And here is what I did.

    const Hash = require('ipfs-only-hash')

    func = async () => {   
      let bgImage = await import(`./images/bg${ex}.png`);
      let bodyImage = await import(`./images/body${ex}.png`);
      let headImage = await import(`./images/head${ex}.png`);
      let eyesImage = await import(`./images/eye${ex}.png`);
      let mouthImage = await import(`./images/mouth${ex}.png`);
      let levelImage = await import(`./images/level${ex}.png`);

      src = await mergeImages([
        bgImage.default,
        bodyImage.default,
        headImage.default,
        eyesImage.default,
        mouthImage.default,
        levelImage.default,
      ]);

      const endOfPrefix = src.indexOf(",");
      const cleanStrData = src.slice(endOfPrefix+1);
      const imageData = Buffer.from(cleanStrData, "base64");
      const imageHash = await Hash.of(imageData);
      console.log("fetch data CID: " + imageHash)
      }

Remove the header of the data, to keep only the data and then hash it it with ipfs-hash-only. The image hash is then written in the .json and the same process is used to hash the .json and know before hand the metadata's ipfs address.

Upvotes: 1

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