Merge #14298: [REST] improve performance for JSON calls

30973e9 [REST] improve performance for JSON calls (Antoine Le Calvez)

Pull request description:

  JSON calls do not use the raw data generated for the .bin and .hex calls.

  By moving the raw data creation into the .bin and .hex switch branches, JSON calls' performance is improved.

  Light benchmarking indicates that fetching 2000 JSON headers is ~25% faster, fetching large JSON blocks is ~4% faster.

Tree-SHA512: 433552c89bac2469d041b48a4a991d5443e4026a3ad7dc5621685386029f22826484218642fa5130c268349a55524ecbc4e30d64c867bd6632e0edd24370cf11

Author: MarcoFalke

src/rest.cpp

@@ -157,20 +157,25 @@ static bool rest_headers(HTTPRequest* req,
         }
     }
 
-    CDataStream ssHeader(SER_NETWORK, PROTOCOL_VERSION);
-    for (const CBlockIndex *pindex : headers) {
-        ssHeader << pindex->GetBlockHeader();
-    }
-
     switch (rf) {
     case RetFormat::BINARY: {
+        CDataStream ssHeader(SER_NETWORK, PROTOCOL_VERSION);
+        for (const CBlockIndex *pindex : headers) {
+            ssHeader << pindex->GetBlockHeader();
+        }
+
         std::string binaryHeader = ssHeader.str();
         req->WriteHeader("Content-Type", "application/octet-stream");
         req->WriteReply(HTTP_OK, binaryHeader);
         return true;
     }
 
     case RetFormat::HEX: {
+        CDataStream ssHeader(SER_NETWORK, PROTOCOL_VERSION);
+        for (const CBlockIndex *pindex : headers) {
+            ssHeader << pindex->GetBlockHeader();
+        }
+
         std::string strHex = HexStr(ssHeader.begin(), ssHeader.end()) + "\n";
         req->WriteHeader("Content-Type", "text/plain");
         req->WriteReply(HTTP_OK, strHex);
@@ -224,18 +229,19 @@ static bool rest_block(HTTPRequest* req,
             return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not found");
     }
 
-    CDataStream ssBlock(SER_NETWORK, PROTOCOL_VERSION | RPCSerializationFlags());
-    ssBlock << block;
-
     switch (rf) {
     case RetFormat::BINARY: {
+        CDataStream ssBlock(SER_NETWORK, PROTOCOL_VERSION | RPCSerializationFlags());
+        ssBlock << block;
         std::string binaryBlock = ssBlock.str();
         req->WriteHeader("Content-Type", "application/octet-stream");
         req->WriteReply(HTTP_OK, binaryBlock);
         return true;
     }
 
     case RetFormat::HEX: {
+        CDataStream ssBlock(SER_NETWORK, PROTOCOL_VERSION | RPCSerializationFlags());
+        ssBlock << block;
         std::string strHex = HexStr(ssBlock.begin(), ssBlock.end()) + "\n";
         req->WriteHeader("Content-Type", "text/plain");
         req->WriteReply(HTTP_OK, strHex);
@@ -360,18 +366,21 @@ static bool rest_tx(HTTPRequest* req, const std::string& strURIPart)
     if (!GetTransaction(hash, tx, Params().GetConsensus(), hashBlock, true))
         return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not found");
 
-    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION | RPCSerializationFlags());
-    ssTx << tx;
-
     switch (rf) {
     case RetFormat::BINARY: {
+        CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION | RPCSerializationFlags());
+        ssTx << tx;
+
         std::string binaryTx = ssTx.str();
         req->WriteHeader("Content-Type", "application/octet-stream");
         req->WriteReply(HTTP_OK, binaryTx);
         return true;
     }
 
     case RetFormat::HEX: {
+        CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION | RPCSerializationFlags());
+        ssTx << tx;
+
         std::string strHex = HexStr(ssTx.begin(), ssTx.end()) + "\n";
         req->WriteHeader("Content-Type", "text/plain");
         req->WriteReply(HTTP_OK, strHex);