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import { ContractWrappers, ExchangeEvents, ExchangeFillEventArgs, ExchangeWrapper } from '@0x/contract-wrappers';
import { Web3ProviderEngine } from '@0x/subproviders';
import { Web3Wrapper } from '@0x/web3-wrapper';
import { LogWithDecodedArgs } from 'ethereum-types';
const BLOCK_FINALITY_THRESHOLD = 10; // When to consider blocks as final. Used to compute default toBlock.
const NUM_BLOCKS_PER_QUERY = 100000; // Number of blocks to query for events at a time.
const EXCHANGE_START_BLOCK = 6271590; // Block number when the Exchange contract was deployed to mainnet.
export class ExchangeEventsSource {
private readonly _exchangeWrapper: ExchangeWrapper;
private readonly _web3Wrapper: Web3Wrapper;
constructor(provider: Web3ProviderEngine, networkId: number) {
this._web3Wrapper = new Web3Wrapper(provider);
const contractWrappers = new ContractWrappers(provider, { networkId });
this._exchangeWrapper = contractWrappers.exchange;
}
// TODO(albrow): Get Cancel and CancelUpTo events.
public async getFillEventsAsync(
fromBlock: number = EXCHANGE_START_BLOCK,
toBlock?: number,
): Promise<Array<LogWithDecodedArgs<ExchangeFillEventArgs>>> {
const calculatedToBlock =
toBlock === undefined
? (await this._web3Wrapper.getBlockNumberAsync()) - BLOCK_FINALITY_THRESHOLD
: toBlock;
let events: Array<LogWithDecodedArgs<ExchangeFillEventArgs>> = [];
for (let currFromBlock = fromBlock; currFromBlock <= calculatedToBlock; currFromBlock += NUM_BLOCKS_PER_QUERY) {
events = events.concat(
await this._getFillEventsForRangeAsync(
currFromBlock,
Math.min(currFromBlock + NUM_BLOCKS_PER_QUERY - 1, calculatedToBlock),
),
);
}
return events;
}
private async _getFillEventsForRangeAsync(
fromBlock: number,
toBlock: number,
): Promise<Array<LogWithDecodedArgs<ExchangeFillEventArgs>>> {
return this._exchangeWrapper.getLogsAsync<ExchangeFillEventArgs>(
ExchangeEvents.Fill,
{
fromBlock,
toBlock,
},
{},
);
}
}
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