Support for block_results RPC method from Client

[devashishdxt]

Tendermint RPC Client does not have support for calling block_results RPC method.

Here's a list of all the supported methods.

[tarcieri]

I took a look at this. The JSON returned from the RPC endpoint differs significantly from what is documented.

From https://tendermint.com/rpc/#blockresults

{


    "height": "10",
    "results": [
     {
      "code": "0",
      "data": "CAFE00F00D"
     },
     {
      "code": "102",
      "data": ""
     }
    ]
}

This curiously seems to be missing the standard JSONRPC fields like jsonrpc, id, and result.

Here is the response I get from gaiad:

{
  "jsonrpc": "2.0",
  "id": "",
  "result": {
    "height": "20",
    "results": {
      "DeliverTx": [
        {
          "log": "[{\"msg_index\":\"0\",\"success\":true,\"log\":\"\"}]",
          "gasWanted": "200000",
          "gasUsed": "35433",
          "tags": [
            {
              "key": "YWN0aW9u",
              "value": "ZWRpdF92YWxpZGF0b3I="
            },
            {
              "key": "ZGVzdGluYXRpb24tdmFsaWRhdG9y",
              "value": "Y29zbW9zdmFsb3BlcjFyd2gwY3hhNzJkM3lsZTNyNGw4Z2Q3dnlwaHJtankya3BlNHg3Mg=="
            },
            {
              "key": "bW9uaWtlcg==",
              "value": "U3BhcmtQb29s"
            },
            {
              "key": "aWRlbnRpdHk=",
              "value": "REU4RTM3MjQwMDYxQjA0RQ=="
            }
          ]
        },
        {
          "log": "[{\"msg_index\":\"0\",\"success\":true,\"log\":\"\"}]",
          "gasWanted": "200000",
          "gasUsed": "81404",
          "tags": [
            {
              "key": "YWN0aW9u",
              "value": "ZGVsZWdhdGU="
            },
            {
              "key": "ZGVsZWdhdG9y",
              "value": "Y29zbW9zMThtY3E0bnA0MG5zYXE4eHozMHR0eWR3a240dXA2Z3JkdHh3eGNq"
            },
            {
              "key": "ZGVzdGluYXRpb24tdmFsaWRhdG9y",
              "value": "Y29zbW9zdmFsb3BlcjE0a24wa2szM3N6cHd1czluaDhuODdmamVsOGRqeDB5MDcweW1tag=="
            }
          ]
        }
      ],
      "EndBlock": {
        "validator_updates": [
          {
            "pub_key": {
              "type": "ed25519",
              "data": "2k346W3w8NFAQh21j1hBp+Mvur+ZhHFuEQk8DEOlN+c="
            },
            "power": "5010"
          }
        ]
      },
      "BeginBlock": {}
    }
  }
}

Looking at this:

https://github.com/tendermint/tendermint/blob/4253e67c07c69be6d7f7263ab03944ce30a9fc90/rpc/core/types/responses.go#L39

// ABCI results from a block
type ResultBlockResults struct {
	Height  int64                `json:"height"`
	Results *state.ABCIResponses `json:"results"`
}

and this:

https://github.com/tendermint/tendermint/blob/4253e67c07c69be6d7f7263ab03944ce30a9fc90/state/store.go#L114

// ABCIResponses retains the responses
// of the various ABCI calls during block processing.
// It is persisted to disk for each height before calling Commit.
type ABCIResponses struct {
	DeliverTx  []*abci.ResponseDeliverTx
	EndBlock   *abci.ResponseEndBlock
	BeginBlock *abci.ResponseBeginBlock
}

I can go ahead and implement it based on that. However what is presently documented appears to be wrong.

[tarcieri]

FWIW, I see there's already an open issue about the documentation:

tendermint/tendermint#3616

and a PR to fix it:

tendermint/tendermint#3708

...however it seems that PR also renamed the fields to be "snake case" (e.g. deliver_tx) instead of CamelCase (e.g. DeliverTx).

I think I can go ahead and impl it with the old names, and update it to the new ones later.

cc @melekes

[tarcieri]

Added in #267. Will be released shortly as tendermint crate v0.8.0.