add erc725 key/value store (#533)

schema.graphql

@@ -113,6 +113,16 @@ type Nft @entity{
 
     "has metadata"
     hasMetadata: Boolean!                                            
+
+    nftData: [NftData!] @derivedFrom(field: "nft")
+}
+
+type NftData @entity{
+    "nft address+key"
+    id: ID!
+    nft: Nft!
+    key: Bytes
+    value: Bytes
   }
 
 type OrderReuse @entity {

src/mappings/nftUpdate.ts

@@ -1,4 +1,4 @@
-import { Nft, NftUpdate } from '../@types/schema'
+import { Nft, NftUpdate, NftData } from '../@types/schema'
 import {
   MetadataCreated,
   MetadataState,
@@ -13,7 +13,8 @@ import {
   RemovedFromMetadataList,
   RemovedManager,
   CleanedPermissions,
-  Transfer
+  Transfer,
+  DataChanged
 } from '../@types/templates/ERC721Template/ERC721Template'
 import { NftUpdateType } from './utils/constants'
 import { getNftToken, getNftTokenWithID } from './utils/tokenUtils'
@@ -257,6 +258,18 @@ export function handleNftTransferred(event: Transfer): void {
   const nft = getNftTokenWithID(id)
   const newOwner = getUser(event.params.to.toHexString())
   nft.owner = newOwner.id
-
   nft.save()
 }
+
+export function handleNftData(event: DataChanged): void {
+  const id = event.address.toHexString() + '-' + event.params.key.toHexString()
+  const nft = getNftToken(event.address)
+  let data = NftData.load(id)
+  if (data == null) {
+    data = new NftData(id)
+  }
+  data.key = event.params.key
+  data.value = event.params.value
+  data.nft = nft.id
+  data.save()
+}

subgraph.template.yaml

@@ -97,6 +97,8 @@ templates:
           handler: handleCleanedPermissions
         - event: Transfer(indexed address,indexed address,indexed uint256)
           handler: handleNftTransferred
+        - event: DataChanged(indexed bytes32,bytes)
+          handler: handleNftData
 
   - name: Dispenser
     kind: ethereum/contract

test/integration/Nft.test.ts

@@ -285,4 +285,26 @@ describe('NFT tests', async () => {
     assert(updatedNft.block < blockNumber + 50, 'incorrect value for: block')
     assert(updatedNft.orderCount === '0', 'incorrect value for: orderCount')
   })
+
+  it('Set a key/value in erc725 store', async () => {
+    await nft.setData(nftAddress, publisher, 'test_key', 'test_value')
+    await sleep(2000)
+    const query = {
+      query: `query {
+                nft(id:"${nftAddress}"){
+                  nftData{
+                    id
+                    key
+                    value
+                  }
+                }
+              }`
+    }
+    const response = await fetch(subgraphUrl, {
+      method: 'POST',
+      body: JSON.stringify(query)
+    })
+    const updatedNft = (await response.json()).data.nft
+    assert(updatedNft.nftData.key !== null, 'incorrect value for key')
+  })
 })