Refactor IPFS hash handling

This now uses the multihashes dependency (which is an ipfs dependency)
to decode/encode the ipfs hashes.

app/lib/kredits/contracts/base.js

@@ -1,5 +1,5 @@
 import Kredits from '../kredits';
-import { fromBytes32 } from '../utils/multihash';
+import multihashes from 'npm:multihashes';
 
 export default class Base {
   constructor(contract) {
@@ -12,11 +12,11 @@ export default class Base {
 
   // TODO: move into utils
   fetchAndMergeIpfsData(data, Serializer) {
-    let ipfsHash = data.ipfsHash;
-
-    if (!ipfsHash) {
+    if (!data.hashSize || data.hashSize === 0) {
       return data;
     }
+    let digest = Kredits.ipfs.Buffer.from(data.ipfsHash.slice(2), 'hex');
+    let ipfsHash = multihashes.encode(digest, data.hashFunction, data.hashSize);
 
     return Kredits.ipfs
       .cat(ipfsHash)
@@ -26,12 +26,12 @@ export default class Base {
       });
   }
 
-  reassembleIpfsHash(data) {
-    let { ipfsHash: digest, hashFunction, hashSize } = data;
-    data.ipfsHash = fromBytes32({ digest, hashFunction, hashSize });
-    delete data.hashFunction;
-    delete data.hashSize;
-
-    return data;
+  decodeIpfsHash(ipfsHash) {
+    let multihash = multihashes.decode(multihashes.fromB58String(ipfsHash));
+    return {
+      ipfsHash: '0x' + multihashes.toHexString(multihash.digest),
+      hashSize: multihash.length,
+      hashFunction: multihash.code
+    };
   }
 }

app/lib/kredits/contracts/contributor.js

@@ -26,7 +26,6 @@ export default class Contributor extends Base {
     id = ethers.utils.bigNumberify(id);
 
     return this.contract.functions.getContributorById(id)
-      .then(this.reassembleIpfsHash)
       .then((data) => {
         // TODO: remove as soon as the contract provides the id
         data.id = id;
@@ -51,7 +50,7 @@ export default class Contributor extends Base {
       .add(new Kredits.ipfs.Buffer(json))
       .then((res) => res[0].hash)
       .then((ipfsHash) => {
-        Object.assign(attributes, toBytes32(ipfsHash));
+        Object.assign(attributes, this.decodeIpfsHash(ipfsHash));
         return attributes;
       })
       .then((attributes) => {

app/lib/kredits/contracts/operator.js

@@ -1,5 +1,6 @@
 import ethers from 'npm:ethers';
 import RSVP from 'rsvp';
+import multihashes from 'npm:multihashes';
 
 import Kredits from '../kredits';
 import ContributionSerializer from '../serializers/contribution';
@@ -26,7 +27,6 @@ export default class Operator extends Base {
     id = ethers.utils.bigNumberify(id);
 
     return this.contract.functions.proposals(id)
-      .then(this.reassembleIpfsHash)
       .then((data) => {
         // TODO: remove as soon as the contract provides the id
         data.id = id;
@@ -51,20 +51,17 @@ export default class Operator extends Base {
       .add(new Kredits.ipfs.Buffer(json))
       .then((res) => res[0].hash)
       .then((ipfsHash) => {
-        Object.assign(attributes, toBytes32(ipfsHash));
+        Object.assign(attributes, this.decodeIpfsHash(ipfsHash));
         return attributes;
       })
-      .then((attributes) => {
-        let { recipientId, amount, digest, hashFunction, hashSize } = attributes;
-
+      .then((attr) => {
         let proposal = [
-          recipientId,
-          amount,
-          digest,
-          hashFunction,
-          hashSize,
+          parseInt(attr.recipientId),
+          parseInt(attr.amount),
+          attr.ipfsHash,
+          attr.hashFunction,
+          attr.hashSize,
         ];
-
         console.log('[kredits] addProposal', ...proposal);
         return this.contract.functions.addProposal(...proposal);
       });