Filtering for eth_getLogs

[dutterbutter]

Changes made in this PR:

• Added PublicFilterAPI
• Added Logs query in querier.go
• Added filterLogs, UnmarshalJSON funcs from go-ethereum
• Added helper funcs

To Test:

make install 
rm -rf ~/.emint*
emintd init moniker --chain-id 3
emintcli config chain-id 3
emintcli config output json
emintcli config indent true
emintcli config trust-node true
emintcli keys add dustin
testpass
testpass
emintcli emintkeys add dustineth
testpass
testpass
emintd add-genesis-account $(emintcli keys show dustin -a) 1000photon,100000000stake
emintd add-genesis-account $(emintcli emintkeys show dustineth -a) 100000000photon,100000000stake
emintd gentx --name dustin
testpass
emintd collect-gentxs
emintd validate-genesis
emintd start --pruning=nothing --rpc.unsafe --log_level "main:info,state:info,mempool:i

Start server with unlocked key to send tx:

emintcli rest-server --laddr "tcp://localhost:8545" --unlock-key dustineth

Deploy Contract and Emit Events:

While ethermint node is running:

git clone git@github.com:ChainSafe/ethermint-scripts.git
cd web3
node test_contract.js

Get logs with a range of blocks

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getLogs","params":[{"fromBlock":"0x7", "toBlock: "0x9"}],"id":6}' -H "Content-Type: application/json" http://localhost:8545/rpc

Get logs with address criteria (this can also take an array of addresses)

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getLogs","params":[{"address":"<contract_address"}],"id":6}' -H "Content-Type: application/json" http://localhost:8545/rpc

Remaining todos for logs:

• Need to set blockHash in Prepare func prior to log entry (will also then enable filtering by blockHash
• Subscribing to event logs
• Using the bloom filter to optimize log querying
• additional filter rpc calls

[austinabell]

Would it not be beneficial to include the range filter on the type you created to abstract this logic so you aren't doing it duplicate times?

[dutterbutter]

can you elaborate on what you mean from the above?

[austinabell]

Just replicating the e.getLogs and filterLogs calls, can't the filter just be generated in this if/ else then call these equivalently outside of it for consistency?

[dutterbutter]

still need some clarity here.... e.getLogs is the actual call to retrieve the logs whereas filterLogs does the filtering. We want to keep this functionality separate when we introduce bloom filters so that we only call filterLogs on the logs that may meet the filter criteria which will be indicated by the bloom filter.

[austinabell]

to be more specific, I just mean having the functionality to create a range filter like you do with NewBlockFilter() then get logs and filter them below this conditional (let me know what you think of this

[austinabell]

The only problem I have is that you are handling block filters and range filters asymmetrically, which is somewhat hard to follow. Also small thing with this is that it adds a linting issue with returning both in the coniditonal (that doesn't matter as much)

[austinabell]

:D