Merge pull request #1082 from 0xProject/fixGetBlocks

Fix block fetch error if block not found

3 files changed, 51 insertions, 20 deletions

diff --git a/packages/web3-wrapper/CHANGELOG.json b/packages/web3-wrapper/CHANGELOG.json
index 1653f388c..ce3f5e3be 100644
--- a/packages/web3-wrapper/CHANGELOG.json
+++ b/packages/web3-wrapper/CHANGELOG.json
@@ -1,5 +1,15 @@
 [
     {
+        "version": "3.0.0",
+        "changes": [
+            {
+                "note":
+                    "Rename `getBlockAsync` to `getBlockIfExistsAsync` and rather then throw if the requested block wasn't found, return undefined.",
+                "pr": 1082
+            }
+        ]
+    },
+    {
         "version": "2.0.3",
         "changes": [
             {
diff --git a/packages/web3-wrapper/src/web3_wrapper.ts b/packages/web3-wrapper/src/web3_wrapper.ts
index af0fe3a72..dc634a57f 100644
--- a/packages/web3-wrapper/src/web3_wrapper.ts
+++ b/packages/web3-wrapper/src/web3_wrapper.ts
@@ -329,23 +329,29 @@ export class Web3Wrapper {
     /**
      * Fetch a specific Ethereum block without transaction data
      * @param blockParam The block you wish to fetch (blockHash, blockNumber or blockLiteral)
-     * @returns The requested block without transaction data
+     * @returns The requested block without transaction data, or undefined if block was not found
+     * (e.g the node isn't fully synced, there was a block re-org and the requested block was uncles, etc...)
      */
-    public async getBlockAsync(blockParam: string | BlockParam): Promise<BlockWithoutTransactionData> {
+    public async getBlockIfExistsAsync(
+        blockParam: string | BlockParam,
+    ): Promise<BlockWithoutTransactionData | undefined> {
         Web3Wrapper._assertBlockParamOrString(blockParam);
         const encodedBlockParam = marshaller.marshalBlockParam(blockParam);
         const method = utils.isHexStrict(blockParam) ? 'eth_getBlockByHash' : 'eth_getBlockByNumber';
         const shouldIncludeTransactionData = false;
-        const blockWithoutTransactionDataWithHexValues = await this._sendRawPayloadAsync<
+        const blockWithoutTransactionDataWithHexValuesOrNull = await this._sendRawPayloadAsync<
             BlockWithoutTransactionDataRPC
         >({
             method,
             params: [encodedBlockParam, shouldIncludeTransactionData],
         });
-        const blockWithoutTransactionData = marshaller.unmarshalIntoBlockWithoutTransactionData(
-            blockWithoutTransactionDataWithHexValues,
-        );
-        return blockWithoutTransactionData;
+        let blockWithoutTransactionDataIfExists;
+        if (!_.isNull(blockWithoutTransactionDataWithHexValuesOrNull)) {
+            blockWithoutTransactionDataIfExists = marshaller.unmarshalIntoBlockWithoutTransactionData(
+                blockWithoutTransactionDataWithHexValuesOrNull,
+            );
+        }
+        return blockWithoutTransactionDataIfExists;
     }
     /**
      * Fetch a specific Ethereum block with transaction data
@@ -376,8 +382,11 @@ export class Web3Wrapper {
      */
     public async getBlockTimestampAsync(blockParam: string | BlockParam): Promise<number> {
         Web3Wrapper._assertBlockParamOrString(blockParam);
-        const { timestamp } = await this.getBlockAsync(blockParam);
-        return timestamp;
+        const blockIfExists = await this.getBlockIfExistsAsync(blockParam);
+        if (_.isUndefined(blockIfExists)) {
+            throw new Error(`Failed to fetch block with blockParam: ${JSON.stringify(blockParam)}`);
+        }
+        return blockIfExists.timestamp;
     }
     /**
      * Retrieve the user addresses available through the backing provider
diff --git a/packages/web3-wrapper/test/web3_wrapper_test.ts b/packages/web3-wrapper/test/web3_wrapper_test.ts
index b4fd8bb44..385c469bf 100644
--- a/packages/web3-wrapper/test/web3_wrapper_test.ts
+++ b/packages/web3-wrapper/test/web3_wrapper_test.ts
@@ -85,28 +85,40 @@ describe('Web3Wrapper tests', () => {
             expect(typeof blockNumber).to.be.equal('number');
         });
     });
-    describe('#getBlockAsync', () => {
+    describe('#getBlockIfExistsAsync', () => {
         it('gets block when supplied a valid BlockParamLiteral value', async () => {
             const blockParamLiteral = BlockParamLiteral.Earliest;
-            const block = await web3Wrapper.getBlockAsync(blockParamLiteral);
-            expect(block.number).to.be.equal(0);
-            expect(utils.isBigNumber(block.difficulty)).to.equal(true);
-            expect(_.isNumber(block.gasLimit)).to.equal(true);
+            const blockIfExists = await web3Wrapper.getBlockIfExistsAsync(blockParamLiteral);
+            if (_.isUndefined(blockIfExists)) {
+                throw new Error('Expected block to exist');
+            }
+            expect(blockIfExists.number).to.be.equal(0);
+            expect(utils.isBigNumber(blockIfExists.difficulty)).to.equal(true);
+            expect(_.isNumber(blockIfExists.gasLimit)).to.equal(true);
         });
         it('gets block when supplied a block number', async () => {
             const blockParamLiteral = 0;
-            const block = await web3Wrapper.getBlockAsync(blockParamLiteral);
-            expect(block.number).to.be.equal(0);
+            const blockIfExists = await web3Wrapper.getBlockIfExistsAsync(blockParamLiteral);
+            if (_.isUndefined(blockIfExists)) {
+                throw new Error('Expected block to exist');
+            }
+            expect(blockIfExists.number).to.be.equal(0);
         });
         it('gets block when supplied a block hash', async () => {
             const blockParamLiteral = 0;
-            const block = await web3Wrapper.getBlockAsync(blockParamLiteral);
-            const sameBlock = await web3Wrapper.getBlockAsync(block.hash as string);
-            expect(sameBlock.number).to.be.equal(0);
+            const blockIfExists = await web3Wrapper.getBlockIfExistsAsync(blockParamLiteral);
+            if (_.isUndefined(blockIfExists)) {
+                throw new Error('Expected block to exist');
+            }
+            const sameBlockIfExists = await web3Wrapper.getBlockIfExistsAsync(blockIfExists.hash as string);
+            if (_.isUndefined(sameBlockIfExists)) {
+                throw new Error('Expected block to exist');
+            }
+            expect(sameBlockIfExists.number).to.be.equal(0);
         });
         it('should throw if supplied invalid blockParam value', async () => {
             const invalidBlockParam = 'deadbeef';
-            expect(web3Wrapper.getBlockAsync(invalidBlockParam)).to.eventually.to.be.rejected();
+            expect(web3Wrapper.getBlockIfExistsAsync(invalidBlockParam)).to.eventually.to.be.rejected();
         });
     });
     describe('#getBlockWithTransactionDataAsync', () => {