From c46da2844b94a088d6e8c443254710b2e78117cc Mon Sep 17 00:00:00 2001
From: Seulgi Kim <seulgi.kim@codechain.io>
Date: Wed, 26 Jun 2019 14:37:10 +0900
Subject: [PATCH] Implement chain_getTransactionSigner

---
 rpc/src/v1/impls/chain.rs  |  8 ++++++++
 rpc/src/v1/traits/chain.rs |  4 ++++
 spec/JSON-RPC.md           | 31 +++++++++++++++++++++++++++++++
 test/src/e2e/chain.test.ts | 30 ++++++++++++++++++++++++++++++
 4 files changed, 73 insertions(+)

diff --git a/rpc/src/v1/impls/chain.rs b/rpc/src/v1/impls/chain.rs
index 3c17ca423f..155b1c2af5 100644
--- a/rpc/src/v1/impls/chain.rs
+++ b/rpc/src/v1/impls/chain.rs
@@ -77,6 +77,14 @@ where
         Ok(self.client.transaction(&id).map(From::from))
     }
 
+    fn get_transaction_signer(&self, transaction_hash: H256) -> Result<Option<PlatformAddress>> {
+        let id = transaction_hash.into();
+        Ok(self.client.transaction(&id).map(|mut tx| {
+            let address = public_to_address(&tx.signer());
+            PlatformAddress::new_v1(tx.network_id, address)
+        }))
+    }
+
     fn contains_transaction(&self, transaction_hash: H256) -> Result<bool> {
         Ok(self.client.transaction_block(&transaction_hash.into()).is_some())
     }
diff --git a/rpc/src/v1/traits/chain.rs b/rpc/src/v1/traits/chain.rs
index ac39a62c8a..e0ce0e1c06 100644
--- a/rpc/src/v1/traits/chain.rs
+++ b/rpc/src/v1/traits/chain.rs
@@ -29,6 +29,10 @@ build_rpc_trait! {
         # [rpc(name = "chain_getTransaction")]
         fn get_transaction(&self, H256) -> Result<Option<Transaction>>;
 
+        /// Gets the signer of transaction with given hash.
+        # [rpc(name = "chain_getTransactionSigner")]
+        fn get_transaction_signer(&self, H256) -> Result<Option<PlatformAddress>>;
+
         /// Query whether the chain has the transaction with given transaction hash.
         # [rpc(name = "chain_containsTransaction")]
         fn contains_transaction(&self, H256) -> Result<bool>;
diff --git a/spec/JSON-RPC.md b/spec/JSON-RPC.md
index a6d2729477..6e5df7136c 100644
--- a/spec/JSON-RPC.md
+++ b/spec/JSON-RPC.md
@@ -281,6 +281,7 @@ When `Transaction` is included in any response, there will be an additional fiel
  * [chain_getBlockByHash](#chain_getblockbyhash)
  * [chain_getBlockTransactionCountByHash](#chain_getblocktransactioncountbyhash)
  * [chain_getTransaction](#chain_gettransaction)
+ * [chain_getTrnsactionSigner](#chain_gettrnsactionsigner)
  * [chain_containsTransaction](#chain_containstransaction)
  * [chain_getTransactionByTracker](#chain_gettransactionbytracker)
  * [chain_getAssetSchemeByTracker](#chain_getassetschemebytracker)
@@ -721,6 +722,36 @@ Errors: `Invalid Params`
 
 [Back to **List of methods**](#list-of-methods)
 
+## chain_getTrnsactionSigner
+Returns the signer of the given transaction hash.
+
+It returns `null` if the transaction hash doesn't exist in the chain.
+
+### Params
+1. tx hash: `H256`
+
+### Returns
+`null` | `PlatformAddress`
+
+### Request Example
+```
+  curl \
+    -H 'Content-Type: application/json' \
+    -d '{"jsonrpc": "2.0", "method": "chain_getTrnsactionSigner", "params": ["0xdb7c705d02e8961880783b4cb3dc051c41e551ade244bed5521901d8de190fc6"], "id": "who-is-authors"}' \
+    localhost:8080
+```
+
+### Response Example
+```
+{
+  "jsonrpc":"2.0",
+  "result": "tccq94guhkrfndnehnca06dlkxcfuq0gdlamvw9ga4f",
+  "id": "who-is-authors"
+}
+```
+
+[Back to **List of methods**](#list-of-methods)
+
 ## chain_containsTransaction
 Returns true if the transaction with the given hash is in the chain.
 
diff --git a/test/src/e2e/chain.test.ts b/test/src/e2e/chain.test.ts
index 781f0dd98c..97bb3b8635 100644
--- a/test/src/e2e/chain.test.ts
+++ b/test/src/e2e/chain.test.ts
@@ -158,6 +158,36 @@ describe("chain", function() {
         expect(signed!.unsigned).to.deep.equal(tx);
     });
 
+    it("sendPayTx, getTransactionSigner", async function() {
+        const tx = node.sdk.core.createPayTransaction({
+            recipient: "tccqxv9y4cw0jwphhu65tn4605wadyd2sxu5yezqghw",
+            quantity: 0
+        });
+        const seq = await node.sdk.rpc.chain.getSeq(faucetAddress);
+        const hash = await node.sdk.rpc.chain.sendSignedTransaction(
+            tx.sign({
+                secret: faucetSecret,
+                fee: 10,
+                seq
+            })
+        );
+        expect(await node.sdk.rpc.chain.containsTransaction(hash)).be.true;
+        const signer = await node.sdk.rpc.sendRpcRequest(
+            "chain_getTransactionSigner",
+            [hash]
+        );
+        expect(signer).equal(faucetAddress.toString());
+        const signed = await node.sdk.rpc.chain.getTransaction(hash);
+        expect(signed).not.null;
+        expect(signed!.unsigned).to.deep.equal(tx);
+        expect(
+            node.sdk.core.classes.PlatformAddress.fromPublic(
+                signed!.getSignerPublic(),
+                { networkId: "tc" }
+            ).toString()
+        ).equal(signer);
+    });
+
     it("getRegularKey, getRegularKeyOwner", async function() {
         const key = node.sdk.util.getPublicFromPrivate(
             node.sdk.util.generatePrivateKey()