How to upload image on hyperledger composer playground?

问题

I am trying to build a Block chain application for distributed image sharing and copyright protection. I am using image as an asset.

So now I want to upload an image on Hyper ledger Composer playground. How can I do that?

回答1:

You can store your file data into the IPFS. IPFS is a protocol and network designed to create a content-addressable, peer-to-peer method of storing and sharing hypermedia in a distributed file system.

For IPFS I recommend you to follow the link

In your application, In js file where you need to store Image. There you have to just write ipfs connectivity code. When you run the application at that time just make sure ipfs daemon started.

IPFS will give you a Hash link after successfully upload a file. You can store that hash into an asset or participate of hyperledger composer.

for example

function toIPFS(file) {
    return new Promise(resolve => {
        const reader = new FileReader();
        reader.onloadend = function() {
        const ipfs = window.IpfsApi('ipfs', 5001,{protocol : "https"}) // Connect to IPFS
        const buf = buffer.Buffer(reader.result) // Convert data into buffer
        ipfs.files.add(buf, (err, result) => { // Upload buffer to IPFS
            if(err) {
              return
            }
             let url = `https://ipfs.io/ipfs/${result[0].hash}`
              resolve('resolved url');
          })
        }
        reader.readAsArrayBuffer(file); // Read Provided File
   });
  }

I hope it will help you. :)

来源：https://stackoverflow.com/questions/54872377/how-to-upload-image-on-hyperledger-composer-playground