Implement custom update of transfer counter in state diff

packages/erc721-watcher/README.md

@@ -143,7 +143,7 @@
   }
   ```
 
-* Run the following GQL query (`storage`) in generated watcher graphql endpoint http://127.0.0.1:3006/graphql
+* Run the following GQL query (`storage`) in generated watcher GraphQL endpoint http://127.0.0.1:3006/graphql
 
   ```graphql
   query {
@@ -214,6 +214,8 @@
 
   * An auto-generated diff_staged IPLDBlock should be added with parent cid pointing to the initial checkpoint IPLDBlock.
 
+  * Custom property `transferCount` should be 1 initially.
+
 * Run the getState query at the endpoint to get the latest IPLDBlock for NFT_ADDRESS:
 
   ```graphql
@@ -290,6 +292,8 @@
 
     * 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.
+
   * 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.
 
   * Run the getState query again at the endpoint with the event blockHash.
@@ -310,6 +314,8 @@
 
 * Open IPFS WebUI http://127.0.0.1:5001/webui and search for IPLDBlocks using their CIDs.
 
+* The state should have auto indexed data and also custom property `transferCount` according to code in hooks file handleEvent method.
+
 ## Customize
 
 * Indexing on an event:

packages/erc721-watcher/src/database.ts

@@ -3,7 +3,7 @@
 //
 
 import assert from 'assert';
-import { Connection, ConnectionOptions, DeepPartial, FindConditions, QueryRunner, FindManyOptions } from 'typeorm';
+import { Connection, ConnectionOptions, DeepPartial, FindConditions, QueryRunner, FindManyOptions, FindOneOptions } from 'typeorm';
 import path from 'path';
 
 import { IPLDDatabase as BaseDatabase, IPLDDatabaseInterface, QueryOptions, StateKind, Where } from '@vulcanize/util';
@@ -28,6 +28,7 @@ import { _Owners } from './entity/_Owners';
 import { _Balances } from './entity/_Balances';
 import { _TokenApprovals } from './entity/_TokenApprovals';
 import { _OperatorApprovals } from './entity/_OperatorApprovals';
+import { TransferCount } from './entity/TransferCount';
 
 export class Database implements IPLDDatabaseInterface {
   _config: ConnectionOptions;
@@ -128,6 +129,35 @@ export class Database implements IPLDDatabaseInterface {
       });
   }
 
+  async getTransferCount (queryRunner: QueryRunner, { id, blockHash }: DeepPartial<TransferCount>): Promise<TransferCount | undefined> {
+    const repo = queryRunner.manager.getRepository(TransferCount);
+    const whereOptions: FindConditions<TransferCount> = { id };
+
+    if (blockHash) {
+      whereOptions.blockHash = blockHash;
+    }
+
+    const findOptions = {
+      where: whereOptions,
+      order: {
+        blockNumber: 'DESC'
+      }
+    };
+
+    let entity = await repo.findOne(findOptions as FindOneOptions<TransferCount>);
+
+    if (!entity && findOptions.where.blockHash) {
+      entity = await this._baseDatabase.getPrevEntityVersion(queryRunner, repo, findOptions);
+    }
+
+    return entity;
+  }
+
+  async saveTransferCount (queryRunner: QueryRunner, transferCount: TransferCount): Promise<TransferCount> {
+    const repo = queryRunner.manager.getRepository(TransferCount);
+    return repo.save(transferCount);
+  }
+
   async _getName ({ blockHash, contractAddress }: { blockHash: string, contractAddress: string }): Promise<_Name | undefined> {
     return this._conn.getRepository(_Name)
       .findOne({

packages/erc721-watcher/src/entity/TransferCount.ts

@@ -0,0 +1,20 @@
+//
+// Copyright 2022 Vulcanize, Inc.
+//
+
+import { Entity, PrimaryColumn, Column, Index } from 'typeorm';
+
+@Entity()
+export class TransferCount {
+  @PrimaryColumn('varchar')
+  id!: string;
+
+  @PrimaryColumn('varchar', { length: 66 })
+  blockHash!: string;
+
+  @Column('integer')
+  blockNumber!: number;
+
+  @Column('integer')
+  count!: number;
+}

packages/erc721-watcher/src/hooks.ts

@@ -7,6 +7,7 @@ import assert from 'assert';
 import { updateStateForMappingType, updateStateForElementaryType } from '@vulcanize/util';
 
 import { Indexer, ResultEvent } from './indexer';
+import { TransferCount } from './entity/TransferCount';
 
 /**
  * Hook function to store an initial state.
@@ -94,18 +95,25 @@ export async function handleEvent (indexer: Indexer, eventData: ResultEvent): Pr
       // Update owner for the tokenId in database.
       await indexer._owners(eventData.block.hash, eventData.contract, tokenId, true);
 
-      // Update custom state diffs with properties name and symbol.
+      // Update custom state diffs with transferCount.
       // {
-      //   "name": "TestNFT",
-      //   "symbol": "TNFT"
+      //   "transferCount": "1"
       // }
-      const { value: name } = await indexer.name(eventData.block.hash, eventData.contract);
-      const nameUpdate = updateStateForElementaryType({}, 'name', name);
-      await indexer.createDiffStaged(eventData.contract, eventData.block.hash, nameUpdate);
+      let transferCount = await indexer.transferCount(eventData.block.hash, eventData.contract);
+
+      if (!transferCount) {
+        transferCount = new TransferCount();
+        transferCount.blockHash = eventData.block.hash;
+        transferCount.blockNumber = eventData.block.number;
+        transferCount.id = eventData.contract;
+        transferCount.count = 0;
+      }
+
+      transferCount.count++;
 
-      const { value: symbol } = await indexer.symbol(eventData.block.hash, eventData.contract);
-      const symbolUpdate = updateStateForElementaryType({}, 'symbol', symbol);
-      await indexer.createDiffStaged(eventData.contract, eventData.block.hash, symbolUpdate);
+      const stateUpdate = updateStateForElementaryType({}, 'transferCount', String(transferCount.count));
+      await indexer.createDiffStaged(eventData.contract, eventData.block.hash, stateUpdate);
+      await indexer.saveOrUpdateTransferCount(transferCount);
 
       break;
     }

packages/erc721-watcher/src/indexer.ts

@@ -40,6 +40,7 @@ import { SyncStatus } from './entity/SyncStatus';
 import { IpldStatus } from './entity/IpldStatus';
 import { BlockProgress } from './entity/BlockProgress';
 import { IPLDBlock } from './entity/IPLDBlock';
+import { TransferCount } from './entity/TransferCount';
 
 const log = debug('vulcanize:indexer');
 
@@ -430,6 +431,39 @@ export class Indexer implements IPLDIndexerInterface {
     return result;
   }
 
+  async transferCount (blockHash: string, contractAddress: string): Promise<TransferCount | undefined> {
+    const dbTx = await this._db.createTransactionRunner();
+    let res;
+
+    try {
+      res = await this._db.getTransferCount(dbTx, { id: contractAddress, blockHash });
+      await dbTx.commitTransaction();
+    } catch (error) {
+      await dbTx.rollbackTransaction();
+      throw error;
+    } finally {
+      await dbTx.release();
+    }
+
+    return res;
+  }
+
+  async saveOrUpdateTransferCount (transferCount: TransferCount) {
+    const dbTx = await this._db.createTransactionRunner();
+    let res;
+
+    try {
+      await this._db.saveTransferCount(dbTx, transferCount);
+    } catch (error) {
+      await dbTx.rollbackTransaction();
+      throw error;
+    } finally {
+      await dbTx.release();
+    }
+
+    return res;
+  }
+
   async _name (blockHash: string, contractAddress: string, diff = false): Promise<ValueResult> {
     const entity = await this._db._getName({ blockHash, contractAddress });
     if (entity) {