feat: new rpc getrawtransactionmulti (#5839)

## Issue being fixed or feature implemented
For platform needs `getrawtransactionmulti` will help to reduce amount
of rpc calls for sake of performance improvement.

## What was done?
Implemented new RPC, basic functional test, release note.

## How Has This Been Tested?
On testnet:
```
> getrawtransactionmulti '{"000000abbe61a4d9b9356cb1d7deb1132d0b444a62869e71c2f3aa8ce2361359":["6e3ef19a3f955ac75a1f84dae60d42bbe11548ef54e37033ff2d91b3c4a09e9c", "415d5fafd5ee24ada8b99c36df339785a3066170c0dca6bb1aa6a5b96cf51e35"], "0":["ec7090f01c0e9b6e29d3be8810b12c780d2fb34372a53b231ce18bb7d2f1e8b0"]}'
> getrawtransactionmulti '{"000000abbe61a4d9b9356cb1d7deb1132d0b444a62869e71c2f3aa8ce2361359":["6e3ef19a3f955ac75a1f84dae60d42bbe11548ef54e37033ff2d91b3c4a09e9c", "415d5fafd5ee24ada8b99c36df339785a3066170c0dca6bb1aa6a5b96cf51e35"], "0":["ec7090f01c0e9b6e29d3be8810b12c780d2fb34372a53b231ce18bb7d2f1e8b0"]}'  true
```

## Breaking Changes
N/A

## Checklist:
- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have added or updated relevant unit/integration/functional/e2e
tests
- [x] I have made corresponding changes to the documentation
- [x] I have assigned this pull request to a milestone

---------

Co-authored-by: pasta <pasta@dashboost.org>

doc/release-notes-5839.md

@@ -0,0 +1,4 @@
+RPC changes
+-----------
+
+New RPC getrawtransactionmulti that can return batch up to 100 rawtransaction at one request.

src/rpc/client.cpp

@@ -107,6 +107,8 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "gettransaction", 1, "include_watchonly" },
     { "gettransaction", 2, "verbose" },
     { "getrawtransaction", 1, "verbose" },
+    { "getrawtransactionmulti", 0, "txid_map" },
+    { "getrawtransactionmulti", 1, "verbose" },
     { "gettxchainlocks", 0, "txids" },
     { "createrawtransaction", 0, "inputs" },
     { "createrawtransaction", 1, "outputs" },

src/rpc/rawtransaction.cpp

@@ -265,6 +265,91 @@ static UniValue getrawtransaction(const JSONRPCRequest& request)
     return result;
 }
 
+static UniValue getrawtransactionmulti(const JSONRPCRequest& request) {
+    RPCHelpMan{
+            "getrawtransactionmulti",
+            "\nReturns the raw transaction data for multiple transactions.\n"
+            "\nThis call is an extension of getrawtransaction that supports multiple transactions.\n"
+            "It accepts a map of block hashes to a list of transaction hashes.\n"
+            "A block hash of 0 indicates transactions not yet mined or in the mempool.\n",
+            {
+                    {"transactions", RPCArg::Type::OBJ, RPCArg::Optional::NO,
+                     "A JSON object with block hashes as keys and lists of transaction hashes as values (no more than 100 in total)",
+                     {
+                             {"blockhash", RPCArg::Type::ARR, RPCArg::Optional::OMITTED,
+                              "The block hash and the list of transaction ids to fetch",
+                              {
+                                      {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "The transaction id"},
+                              }},
+                     }},
+                    {"verbose", RPCArg::Type::BOOL, /* default */ "false",
+                     "If false, return a string, otherwise return a json object"},
+            },
+            RPCResults{},
+            RPCExamples{
+                    HelpExampleCli("getrawtransactionmulti",
+                                   R"('{"blockhash1":["txid1","txid2"], "0":["txid3"]}')")
+                    + HelpExampleRpc("getrawtransactionmulti",
+                                     R"('{"blockhash1":["txid1","txid2"], "0":["txid3"]})")
+            },
+    }.Check(request);
+
+    // Parse arguments
+    UniValue transactions{request.params[0].get_obj()};
+    // Accept either a bool (true) or a num (>=1) to indicate verbose output.
+    bool fVerbose{false};
+    if (!request.params[1].isNull()) {
+        fVerbose = request.params[1].isNum() ? (request.params[1].get_int() != 0) : request.params[1].get_bool();
+    }
+
+    const NodeContext& node{EnsureAnyNodeContext(request.context)};
+    const ChainstateManager& chainman{EnsureChainman(node)};
+    const LLMQContext& llmq_ctx{EnsureLLMQContext(node)};
+    CTxMemPool& mempool{EnsureMemPool(node)};
+
+    if (transactions.size() > 100) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Up to 100 blocks and txids only");
+    }
+
+    size_t count{0};
+    UniValue result(UniValue::VOBJ);
+    for (const std::string& blockhash_str : transactions.getKeys()) {
+        const uint256 blockhash{uint256S(blockhash_str)};
+        const UniValue txids = transactions[blockhash_str].get_array();
+
+        CBlockIndex* blockindex{blockhash.IsNull() ? nullptr : WITH_LOCK(::cs_main, return chainman.m_blockman.LookupBlockIndex(blockhash))};
+        if (blockindex == nullptr && !blockhash.IsNull()) {
+            for (const auto idx : irange::range(txids.size())) {
+                result.pushKV(txids[idx].get_str(), "None");
+            }
+            continue;
+        }
+
+        count += txids.size();
+        if (count > 100) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Up to 100 txids in total");
+        }
+        for (const auto idx : irange::range(txids.size())) {
+            const std::string txid_str = txids[idx].get_str();
+            const uint256 txid = ParseHashV(txid_str, "transaction id");
+
+            uint256 hash_block;
+            const CTransactionRef tx = GetTransaction(blockindex, &mempool, txid, Params().GetConsensus(), hash_block);
+            if (!tx) {
+                result.pushKV(txid_str, "None");
+            } else if (fVerbose) {
+                UniValue tx_data{UniValue::VOBJ};
+                TxToJSON(*tx, hash_block, mempool, chainman.ActiveChainstate(), *llmq_ctx.clhandler, *llmq_ctx.isman, tx_data);
+                result.pushKV(txid_str, tx_data);
+            } else {
+                result.pushKV(txid_str, EncodeHexTx(*tx));
+            }
+        }
+    }
+
+    return result;
+}
+
 static UniValue gettxchainlocks(const JSONRPCRequest& request)
 {
     RPCHelpMan{
@@ -1885,6 +1970,7 @@ static const CRPCCommand commands[] =
   //  --------------------- ------------------------        -----------------------     ----------
     { "rawtransactions",    "getassetunlockstatuses",       &getassetunlockstatuses,    {"indexes"} },
     { "rawtransactions",    "getrawtransaction",            &getrawtransaction,         {"txid","verbose","blockhash"} },
+    { "rawtransactions",    "getrawtransactionmulti",       &getrawtransactionmulti,    {"txid_map","verbose"} },
     { "rawtransactions",    "gettxchainlocks",              &gettxchainlocks,           {"txids"} },
     { "rawtransactions",    "createrawtransaction",         &createrawtransaction,      {"inputs","outputs","locktime"} },
     { "rawtransactions",    "decoderawtransaction",         &decoderawtransaction,      {"hexstring"} },

test/functional/rpc_rawtransaction.py

@@ -306,19 +306,24 @@ class RawTransactionsTest(BitcoinTestFramework):
         # 1. valid parameters - only supply txid
         txId = rawTx["txid"]
         assert_equal(self.nodes[0].getrawtransaction(txId), rawTxSigned['hex'])
+        assert_equal(self.nodes[0].getrawtransactionmulti({"0":[txId]})[txId], rawTxSigned['hex'])
 
         # 2. valid parameters - supply txid and 0 for non-verbose
         assert_equal(self.nodes[0].getrawtransaction(txId, 0), rawTxSigned['hex'])
+        assert_equal(self.nodes[0].getrawtransactionmulti({"0":[txId]}, 0)[txId], rawTxSigned['hex'])
 
         # 3. valid parameters - supply txid and False for non-verbose
         assert_equal(self.nodes[0].getrawtransaction(txId, False), rawTxSigned['hex'])
+        assert_equal(self.nodes[0].getrawtransactionmulti({"0":[txId]}, False)[txId], rawTxSigned['hex'])
 
         # 4. valid parameters - supply txid and 1 for verbose.
         # We only check the "hex" field of the output so we don't need to update this test every time the output format changes.
         assert_equal(self.nodes[0].getrawtransaction(txId, 1)["hex"], rawTxSigned['hex'])
+        assert_equal(self.nodes[0].getrawtransactionmulti({"0":[txId]}, 1)[txId]['hex'], rawTxSigned['hex'])
 
         # 5. valid parameters - supply txid and True for non-verbose
         assert_equal(self.nodes[0].getrawtransaction(txId, True)["hex"], rawTxSigned['hex'])
+        assert_equal(self.nodes[0].getrawtransactionmulti({"0":[txId]}, True)[txId]['hex'], rawTxSigned['hex'])
 
         # 6. invalid parameters - supply txid and string "Flase"
         assert_raises_rpc_error(-1, "not a boolean", self.nodes[0].getrawtransaction, txId, "Flase")