1 files changed, 75 insertions, 0 deletions
diff --git a/packages/pipeline/src/events.ts b/packages/pipeline/src/events.ts
new file mode 100644
index 000000000..a6e1e4ad3
--- /dev/null
+++ b/packages/pipeline/src/events.ts
@@ -0,0 +1,75 @@
+import { AbiDecoder } from '@0xproject/utils';
+import { default as axios } from 'axios';
+import { BlockParam, BlockParamLiteral, DecodedLogArgs, LogEntry, LogWithDecodedArgs } from 'ethereum-types';
+import * as R from 'ramda';
+
+import { artifacts } from './artifacts';
+
+// const EXCHANGE_ADDRESS = '0x4f833a24e1f95d70f028921e27040ca56e09ab0b';
+const ETHERSCAN_URL = 'https://api.etherscan.io/api';
+// TOOD(albrow): Pass this in as a constructor argument instead of an env var.
+const ETHERSCAN_API_KEY = process.env.ETHERSCAN_API_KEY;
+
+// Raw response from etherescan.io
+interface EventsResponse {
+    status: string;
+    message: string;
+    result: EventsResponseResult[];
+}
+
+// Events as represented in the response from etherscan.io
+interface EventsResponseResult {
+    address: string;
+    topics: string[];
+    data: string;
+    blockNumber: string;
+    timeStamp: string;
+    gasPrice: string;
+    gasUsed: string;
+    logIndex: string;
+    transactionHash: string;
+    transactionIndex: string;
+}
+
+// Parses and abi-decodes the fill events response from etherscan.io.
+const parseFillEventsResponse = R.pipe(R.map(convertResponseToLogEntry), R.map(tryToDecodeLogOrNoop));
+
+function convertResponseToLogEntry(result: EventsResponseResult): LogEntry {
+    const radix = 10;
+    return {
+        logIndex: parseInt(result.logIndex, radix),
+        transactionIndex: parseInt(result.logIndex, radix),
+        transactionHash: result.transactionHash,
+        blockHash: '',
+        blockNumber: parseInt(result.blockNumber, radix),
+        address: result.address,
+        data: result.data,
+        topics: result.topics,
+    };
+}
+
+function tryToDecodeLogOrNoop(log: LogEntry): LogWithDecodedArgs<DecodedLogArgs> {
+    const abiDecoder = new AbiDecoder([artifacts.Exchange.compilerOutput.abi]);
+    const logWithDecodedArgs = abiDecoder.tryToDecodeLogOrNoop(log);
+    // tslint:disable-next-line:no-unnecessary-type-assertion
+    return logWithDecodedArgs as LogWithDecodedArgs<DecodedLogArgs>;
+}
+
+/**
+ * Gets the decoded events for a specific contract and block range.
+ * @param contractAddress  The address of the contract to get the events for.
+ * @param fromBlock The start of the block range to get events for (inclusive).
+ * @param toBlock The end of the block range to get events for (inclusive).
+ * @returns A list of decoded events.
+ */
+export async function getContractEventsAsync(
+    contractAddress: string,
+    fromBlock: BlockParam = BlockParamLiteral.Earliest,
+    toBlock: BlockParam = BlockParamLiteral.Latest,
+): Promise<Array<LogWithDecodedArgs<DecodedLogArgs>>> {
+    const fullURL = `${ETHERSCAN_URL}?module=logs&action=getLogs&address=${contractAddress}&fromBlock=${fromBlock}&toBlock=${toBlock}&apikey=${ETHERSCAN_API_KEY}`;
+    const resp = await axios.get<EventsResponse>(fullURL);
+    // TODO(albrow): Check response code.
+    const decodedEvents = parseFillEventsResponse(resp.data.result);
+    return decodedEvents;
+}