RPC API update

[JackyWYX]

Problem

From our recent investigation to the RPC service degradation, we found the issue is mostly caused by the following two RPCs:

• getBlocks
• getLogs

The two RPCs will query block information with the given range. The range is unlimited, which means if a user call these RPC methods from genesis to latest, the server will loop through 10 million blocks to give the result, which will take a large portion of server endpoints.

Solution

We are planning an upcoming release which contains the fix #3830 to be deployed to RPC server. This fix will add a limitation to the two RPC methods, which is currently set as 1024 blocks for each request. If a user request a batch larger than 1024, the RPC will return an error:

> curl -s --request POST 'http://localhost:9500/' --header 'Content-Type: application/json' --data-raw '{
    "jsonrpc": "2.0",
    "method": "hmyv2_getBlocks", 
    "params": [
        1, 
        1026, 
        {
            "withSigners": false, 
            "fullTx": false,
            "inclStaking": false
        }
    ], 
    "id": 1
}'
{
    "jsonrpc":"2.0",
    "id":1,
    "error":{
        "code":-32000,
        "message":"GetBlocks query must be smaller than size 1024"
    }
} 

Impact and execution

The two RPCs are not backward-compatible, thus will potentially incur service interruption in DAPPs. We encourage all DAPP developers to check the usage of this RPC method, and update the code to avoid any service interruption.

We are planning to release this version to our RPC server at Aug 9th, 2021.

Please leave a comment below if you have any concerns or questions regarding the change.

[gupadhyaya]

In terms of the impact on sdks:

• harmony-js sdk has two apis that call getLog rpc hmy_test_ws.blockchain.logs(options) and hmy_test_ws.messenger.send as shown below:

const { Harmony } = require("@harmony-js/core");
const { ChainID, ChainType } = require("@harmony-js/utils");
const hmy_test_ws = new Harmony("wss://ws.s0.b.hmny.io", {
    chainType: ChainType.Harmony,
    chainId: ChainID.HmyTestnet,
  });
  let options = {
    fromBlock: "0xC849ED",
    toBlock: "0xC85D75",
    address: "0x87e91c87196de58f6dc413d81c699da8ef39e4b9",
  };

  const logs = await hmy_test_ws.messenger.send(
    "hmy_getLogs",
    [options],
    hmy_ws.chainType,
    hmy_ws.chainId
  );
  console.log(logs.error);

and

let options = {
  fromBlock: '0xC849ED',
  toBlock: '0xC85D75',
  address: "0x87e91c87196de58f6dc413d81c699da8ef39e4b9",
};
let logs = hmy_test_ws.blockchain.logs(options);
logs.on("data", function (res, err) {
  if (err) {
    console.log(err);
  }
  console.log(res);
}).on("error", (err) => {
  console.log(err);
});

• web3js filter api and getPastEvents contract api are also effected

const filter = web3.eth.filter({
  fromBlock: 0,
  toBlock: 'latest',
  address: contractAddress,
  topics: [web3.sha3('newtest(string,uint256,string,string,uint256)')]
})

filter.watch((error, result) => {
   //
})

and

await contract.getPastEvents('MyEvent', {
      filter: {},
      fromBlock: fromBlockNum,
      toBlock: toBlockNum,
    });