126 lines
2.8 KiB
Markdown
126 lines
2.8 KiB
Markdown
-----
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Documentation: [html](https://docs-beta.ethers.io/)
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-----
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Events
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======
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Solidity Topics
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---------------
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Logs and Filtering
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------------------
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### Filters
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Example Log Matching
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```javascript
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// <hide>
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const tokenAddress = ethers.constants.AddressZero;
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const myAddress = ethers.constants.AddressZero;
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const myOtherAddress = ethers.constants.AddressZero;
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const id = ethers.utils.id;
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const hexZeroPad = ethers.utils.hexZeroPad;
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// </hide>
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// Short example of manually creating filters for an ERC-20
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// Transfer event.
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//
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// Most users should generally use the Contract API to
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// compute filters, as it is much simpler, but this is
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// provided as an illustration for those curious. See
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// below for examples of the equivalent Contract API.
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// ERC-20:
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// Transfer(address indexed src, address indexed dst, uint val)
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//
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// -------------------^
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// ----------------------------------------^
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//
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// Notice that only *src* and *dst* are *indexed*, so ONLY they
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// qualify for filtering.
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//
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// Also, note that in Solidity an Event uses the first topic to
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// identify the Event name; for Transfer this will be:
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// id("Transfer(address,address,uint256)")
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//
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// Other Notes:
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// - A topic must be 32 bytes; so shorter types must be padded
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// List all token transfers *from* myAddress
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filter = {
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address: tokenAddress,
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topics: [
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id("Transfer(address,address,uint256)"),
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hexZeroPad(myAddress, 32)
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]
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}
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// List all token transfers *to* myAddress:
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filter = {
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address: tokenAddress,
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topics: [
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id("Transfer(address,address,uint256)"),
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null,
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hexZeroPad(myAddress, 32)
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]
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}
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// List all token transfers *to* myAddress or myOtherAddress:
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filter = {
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address: tokenAddress,
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topics: [
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id("Transfer(address,address,uint256)"),
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null,
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[
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hexZeroPad(myAddress, 32),
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hexZeroPad(myOtherAddress, 32),
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]
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]
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}
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```
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To simplify life, ..., explain here, the contract API
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```javascript
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// <hide>
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const tokenAddress = "0x6B175474E89094C44Da98b954EedeAC495271d0F"; // DAI
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const myAddress = "0x8ba1f109551bD432803012645Ac136ddd64DBA72";
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const otherAddress = "0xEA517D5a070e6705Cc5467858681Ed953d285Eb9";
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const provider = ethers.getDefaultProvider();
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const Contract = ethers.Contract;
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// </hide>
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const abi = [
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"event Transfer(address indexed src, address indexed dst, uint val)"
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];
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const contract = new Contract(tokenAddress, abi, provider);
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// List all token transfers *from* myAddress
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contract.filters.Transfer(myAddress)
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//!
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// List all token transfers *to* myAddress:
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contract.filters.Transfer(null, myAddress)
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//!
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// List all token transfers *from* myAddress *to* otherAddress:
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contract.filters.Transfer(myAddress, otherAddress)
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//!
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// List all token transfers *to* myAddress OR otherAddress:
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contract.filters.Transfer(null, [ myAddress, otherAddress ])
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//!
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```
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### Other Things? TODO
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