Add GQL API for transferCount entity (#129)

packages/erc721-watcher/demo.md

@@ -161,7 +161,7 @@
 
   * Custom property `transferCount` should be 1 initially.
 
-* Run the getState query at the endpoint to get the latest IPLDBlock for NFT_ADDRESS:
+* Run the `getState` query at the endpoint to get the latest IPLDBlock for NFT_ADDRESS:
 
   ```graphql
   query {
@@ -190,7 +190,25 @@
 
   * `data` contains the default state and also the custom state property `transferCount` that is indexed in [hooks.ts](./src/hooks.ts) file.
 
-* Get the latest blockHash and run the following query for `balanceOf` and `ownerOf` (`eth_call`):
+* Get the latest blockHash and run the following query for `transferCount` entity:
+
+  ```graphql
+  query {
+    transferCount(
+      block: {
+        hash: "LATEST_BLOCK_HASH"
+      }
+      id: "NFT_ADDRESS"
+    ) {
+      id
+      count
+    }
+  }
+  ```
+
+  *Note: Contract address is assigned to the Entity ID.*
+
+* With the latest blockHash, run the following query for `balanceOf` and `ownerOf` (`eth_call`):
 
   ```graphql
   query {
@@ -239,11 +257,13 @@
 
   * An auto-generated `diff_staged` IPLDBlock should be added with parent CID pointing to the previous IPLDBlock.
 
-  * Custom property `transferCount` should be incremented after transfer. This can be checked in the getState query and in IPFS webUI mentioned in the later steps.
+  * Custom property `transferCount` should be incremented after transfer. This can be checked in the `getState` query and in IPFS webUI mentioned in the later steps.
 
-* Get the latest blockHash and replace the blockHash in the above query. The result should be different and the token should be transferred to the recipient.
+* Get the latest blockHash and replace the blockHash in the above `eth_call` query. The result should be different and the token should be transferred to the recipient.
 
-* Run the getState query again at the endpoint with the event blockHash.
+* Run the `getState` query again at the endpoint with the event blockHash.
+
+* Run the `transferCount` entity query again with the latest blockHash. The updated count should be returned.
 
 * After the `diff` block has been created (can check if event block number pruned in yarn server log), create a checkpoint using CLI in `packages/erc721-watcher`:
 
@@ -251,7 +271,7 @@
   yarn checkpoint --address $NFT_ADDRESS
   ```
 
-  * Run the getState query again with the output blockHash and kind checkpoint at the endpoint.
+  * Run the `getState` query again with the output blockHash and kind checkpoint at the endpoint.
 
   * The latest checkpoint should have the aggregate of state diffs since the last checkpoint.
 

packages/erc721-watcher/src/database.ts

@@ -3,7 +3,7 @@
 //
 
 import assert from 'assert';
-import { Connection, ConnectionOptions, DeepPartial, FindConditions, QueryRunner, FindManyOptions, FindOneOptions } from 'typeorm';
+import { Connection, ConnectionOptions, DeepPartial, FindConditions, QueryRunner, FindManyOptions, FindOneOptions, LessThanOrEqual } from 'typeorm';
 import path from 'path';
 
 import { IPLDDatabase as BaseDatabase, IPLDDatabaseInterface, QueryOptions, StateKind, Where } from '@vulcanize/util';
@@ -129,7 +129,7 @@ export class Database implements IPLDDatabaseInterface {
       });
   }
 
-  async getTransferCount (queryRunner: QueryRunner, { id, blockHash }: DeepPartial<TransferCount>): Promise<TransferCount | undefined> {
+  async getTransferCount (queryRunner: QueryRunner, { id, blockHash, blockNumber }: DeepPartial<TransferCount>): Promise<TransferCount | undefined> {
     const repo = queryRunner.manager.getRepository(TransferCount);
     const whereOptions: FindConditions<TransferCount> = { id };
 
@@ -137,6 +137,10 @@ export class Database implements IPLDDatabaseInterface {
       whereOptions.blockHash = blockHash;
     }
 
+    if (blockNumber) {
+      whereOptions.blockNumber = LessThanOrEqual(blockNumber);
+    }
+
     const findOptions = {
       where: whereOptions,
       order: {

packages/erc721-watcher/src/hooks.ts

@@ -100,16 +100,17 @@ export async function handleEvent (indexer: Indexer, eventData: ResultEvent): Pr
       //   "transferCount": "1"
       // }
       // Fetch transferCount entity from database.
-      let transferCount = await indexer.transferCount(eventData.block.hash, eventData.contract);
+      let transferCount = await indexer.getTransferCount(eventData.contract, eventData.block);
 
       if (!transferCount) {
         transferCount = new TransferCount();
-        transferCount.blockHash = eventData.block.hash;
-        transferCount.blockNumber = eventData.block.number;
         transferCount.id = eventData.contract;
         transferCount.count = 0;
       }
 
+      transferCount.blockHash = eventData.block.hash;
+      transferCount.blockNumber = eventData.block.number;
+
       // Increment count on transfer event.
       transferCount.count++;
 

packages/erc721-watcher/src/indexer.ts

@@ -431,12 +431,12 @@ export class Indexer implements IPLDIndexerInterface {
     return result;
   }
 
-  async transferCount (blockHash: string, contractAddress: string): Promise<TransferCount | undefined> {
+  async getTransferCount (id: string, block: BlockHeight): Promise<TransferCount | undefined> {
     const dbTx = await this._db.createTransactionRunner();
     let res;
 
     try {
-      res = await this._db.getTransferCount(dbTx, { id: contractAddress, blockHash });
+      res = await this._db.getTransferCount(dbTx, { id, blockHash: block.hash, blockNumber: block.number });
       await dbTx.commitTransaction();
     } catch (error) {
       await dbTx.rollbackTransaction();

packages/erc721-watcher/src/resolvers.ts

@@ -12,6 +12,7 @@ import { ValueResult, BlockHeight, StateKind } from '@vulcanize/util';
 
 import { Indexer } from './indexer';
 import { EventWatcher } from './events';
+import { TransferCount } from './entity/TransferCount';
 
 const log = debug('vulcanize:resolver');
 
@@ -128,6 +129,12 @@ export const createResolvers = async (indexer: Indexer, eventWatcher: EventWatch
         return indexer._operatorApprovals(blockHash, contractAddress, key0, key1);
       },
 
+      transferCount: async (_: any, { id, block = {} }: { id: string, block: BlockHeight }) => {
+        log('transferCount', id, block);
+
+        return indexer.getTransferCount(id, block);
+      },
+
       events: async (_: any, { blockHash, contractAddress, name }: { blockHash: string, contractAddress: string, name?: string }) => {
         log('events', blockHash, contractAddress, name);
 

packages/erc721-watcher/src/schema.gql

@@ -4,6 +4,11 @@ scalar BigDecimal
 
 scalar Bytes
 
+input Block_height {
+  hash: Bytes
+  number: Int
+}
+
 type Proof {
   data: String!
 }
@@ -99,6 +104,12 @@ type Query {
   _operatorApprovals(blockHash: String!, contractAddress: String!, key0: String!, key1: String!): ResultBoolean!
   getStateByCID(cid: String!): ResultIPLDBlock
   getState(blockHash: String!, contractAddress: String!, kind: String): ResultIPLDBlock
+  transferCount(id: String!, block: Block_height): TransferCount!
+}
+
+type TransferCount {
+  id: ID!
+  count: Int!
 }
 
 type Mutation {