From 864656eae0e8b9cb795ad3f4f8d13924ace8a002 Mon Sep 17 00:00:00 2001
From: Ferran Borreguero <ferranbt@protonmail.com>
Date: Mon, 19 Feb 2024 17:45:14 +0000
Subject: [PATCH] Add JsonRPC protocol contract (#43)

* Add JsonRPC protocol contract

* Rename JsonRPC to EthJsonRPC

* Update forge

* Fix README

* Update README

* Update README
---
 README.md                       | 19 +++++++++--
 lib/forge-std                   |  2 +-
 src/protocols/EthJsonRPC.sol    | 57 +++++++++++++++++++++++++++++++++
 test/protocols/EthJsonRPC.t.sol | 24 ++++++++++++++
 4 files changed, 99 insertions(+), 3 deletions(-)
 create mode 100644 src/protocols/EthJsonRPC.sol
 create mode 100644 test/protocols/EthJsonRPC.t.sol

diff --git a/README.md b/README.md
index b7092d8..e3d9f07 100644
--- a/README.md
+++ b/README.md
@@ -84,12 +84,27 @@ contract Example {
 }
 ```
 
-### protocols/ChatGPT.sol
+### protocols/EthJsonRPC.sol
 
-Helper library to send completion requests to ChatGPT.
+Helper library to interact with the Ethereum JsonRPC protocol.
 
 #### Example usage
 
+```solidity
+import "suave-std/protocols/EthJsonRPC.sol";
+
+contract Example {
+    function example() {
+        EthJsonRPC jsonrpc = new EthJsonRPC("http://...");
+        jsonrpc.nonce(address(this));
+    }
+}
+```
+
+### protocols/ChatGPT.sol
+
+Helper library to send completion requests to ChatGPT.
+
 ```solidity
 import "suave-std/protocols/ChatGPT.sol";
 
diff --git a/lib/forge-std b/lib/forge-std
index 4513bc2..3725a22 160000
--- a/lib/forge-std
+++ b/lib/forge-std
@@ -1 +1 @@
-Subproject commit 4513bc2063f23c57bee6558799584b518d387a39
+Subproject commit 3725a22ae52065de9966beaf32de69aee46fb530
diff --git a/src/protocols/EthJsonRPC.sol b/src/protocols/EthJsonRPC.sol
new file mode 100644
index 0000000..03b70ed
--- /dev/null
+++ b/src/protocols/EthJsonRPC.sol
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: Unlicense
+pragma solidity ^0.8.13;
+
+import "src/suavelib/Suave.sol";
+import "solady/src/utils/JSONParserLib.sol";
+import "solady/src/utils/LibString.sol";
+
+contract EthJsonRPC {
+    using JSONParserLib for *;
+
+    string endpoint;
+
+    constructor(string memory _endpoint) {
+        endpoint = _endpoint;
+    }
+
+    function nonce(address addr) public returns (uint256) {
+        bytes memory body = abi.encodePacked(
+            '{"jsonrpc":"2.0","method":"eth_getTransactionCount","params":["',
+            LibString.toHexStringChecksummed(addr),
+            '","latest"],"id":1}'
+        );
+
+        JSONParserLib.Item memory item = doRequest(string(body));
+        uint256 val = JSONParserLib.parseUintFromHex(trimQuotes(item.value()));
+        return val;
+    }
+
+    function doRequest(string memory body) public returns (JSONParserLib.Item memory) {
+        Suave.HttpRequest memory request;
+        request.method = "POST";
+        request.url = endpoint;
+        request.headers = new string[](1);
+        request.headers[0] = "Content-Type: application/json";
+        request.body = bytes(body);
+
+        bytes memory output = Suave.doHTTPRequest(request);
+
+        JSONParserLib.Item memory item = string(output).parse();
+        return item.at('"result"');
+    }
+
+    function trimQuotes(string memory input) private pure returns (string memory) {
+        bytes memory inputBytes = bytes(input);
+        require(
+            inputBytes.length >= 2 && inputBytes[0] == '"' && inputBytes[inputBytes.length - 1] == '"', "Invalid input"
+        );
+
+        bytes memory result = new bytes(inputBytes.length - 2);
+
+        for (uint256 i = 1; i < inputBytes.length - 1; i++) {
+            result[i - 1] = inputBytes[i];
+        }
+
+        return string(result);
+    }
+}
diff --git a/test/protocols/EthJsonRPC.t.sol b/test/protocols/EthJsonRPC.t.sol
new file mode 100644
index 0000000..47ff4a8
--- /dev/null
+++ b/test/protocols/EthJsonRPC.t.sol
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+import "forge-std/Test.sol";
+import "src/Test.sol";
+import "solady/src/utils/LibString.sol";
+import "src/protocols/EthJsonRPC.sol";
+
+contract EthJsonRPCTest is Test, SuaveEnabled {
+    function testEthJsonRPCGetNonce() public {
+        EthJsonRPC ethjsonrpc = getEthJsonRPC();
+
+        uint256 nonce = ethjsonrpc.nonce(address(this));
+        assertEq(nonce, 0);
+    }
+
+    function getEthJsonRPC() public returns (EthJsonRPC ethjsonrpc) {
+        try vm.envString("JSONRPC_ENDPOINT") returns (string memory endpoint) {
+            ethjsonrpc = new EthJsonRPC(endpoint);
+        } catch {
+            vm.skip(true);
+        }
+    }
+}