text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2014 The Bitcoin developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include "chain.h"
  #include "chainparams.h"
  #include "primitives/block.h"
  #include "primitives/transaction.h"
  #include "validation.h"
  #include "httpserver.h"
  #include "rpc/server.h"
  #include "streams.h"
  #include "sync.h"
  #include "txmempool.h"
  #include "utilstrencodings.h"
  #include "validation.h"
  #include "version.h"
  
  #include <boost/algorithm/string.hpp>
  
  #include <univalue.h>
  
  using namespace std;
  
  static const int MAX_GETUTXOS_OUTPOINTS = 15; //allow a max of 15 outpoints to be queried at once
  
  enum RetFormat {
      RF_UNDEF,
      RF_BINARY,
      RF_HEX,
      RF_JSON,
  };
  
  static const struct {
      enum RetFormat rf;
      const char* name;
  } rf_names[] = {
        {RF_UNDEF, ""},
        {RF_BINARY, "bin"},
        {RF_HEX, "hex"},
        {RF_JSON, "json"},
  };
  
  struct CCoin {
      uint32_t nHeight;
      CTxOut out;
  
      ADD_SERIALIZE_METHODS
  
      CCoin() : nHeight(0) {}
      CCoin(Coin&& in) : nHeight(in.nHeight), out(std::move(in.out)) {}
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action)
      {
          uint32_t nTxVerDummy = 0;
          READWRITE(nTxVerDummy);
          READWRITE(nHeight);
          READWRITE(out);
      }
  };
  
  extern void TxToJSON(const CTransaction& tx, const uint256 hashBlock, UniValue& entry);
  extern UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool txDetails = false);
  extern UniValue mempoolInfoToJSON();
  extern UniValue mempoolToJSON(bool fVerbose = false);
  extern void ScriptPubKeyToJSON(const CScript& scriptPubKey, UniValue& out, bool fIncludeHex);
  extern UniValue blockheaderToJSON(const CBlockIndex* blockindex);
  
  static bool RESTERR(HTTPRequest* req, enum HTTPStatusCode status, string message)
  {
      req->WriteHeader("Content-Type", "text/plain");
      req->WriteReply(status, message + "\r\n");
      return false;
  }
  
  static enum RetFormat ParseDataFormat(vector<string>& params, const string& strReq)
  {
      boost::split(params, strReq, boost::is_any_of("."));
      if (params.size() > 1) {
          for (unsigned int i = 0; i < ARRAYLEN(rf_names); i++)
              if (params[1] == rf_names[i].name)
                  return rf_names[i].rf;
      }
  
      return rf_names[0].rf;
  }
  
  static string AvailableDataFormatsString()
  {
      string formats = "";
      for (unsigned int i = 0; i < ARRAYLEN(rf_names); i++)
          if (strlen(rf_names[i].name) > 0) {
              formats.append(".");
              formats.append(rf_names[i].name);
              formats.append(", ");
          }
  
      if (formats.length() > 0)
          return formats.substr(0, formats.length() - 2);
  
      return formats;
  }
  
  static bool ParseHashStr(const string& strReq, uint256& v)
  {
      if (!IsHex(strReq) || (strReq.size() != 64))
          return false;
  
      v.SetHex(strReq);
      return true;
  }
  
  static bool CheckWarmup(HTTPRequest* req)
  {
      std::string statusmessage;
      if (RPCIsInWarmup(&statusmessage))
           return RESTERR(req, HTTP_SERVICE_UNAVAILABLE, "Service temporarily unavailable: " + statusmessage);
      return true;
  }
  
  static bool rest_headers(HTTPRequest* req,
                           const std::string& strURIPart)
  {
      if (!CheckWarmup(req))
          return false;
      vector<string> params;
      const RetFormat rf = ParseDataFormat(params, strURIPart);
      vector<string> path;
      boost::split(path, params[0], boost::is_any_of("/"));
  
      if (path.size() != 2)
          return RESTERR(req, HTTP_BAD_REQUEST, "No header count specified. Use /rest/headers/<count>/<hash>.<ext>.");
  
      long count = strtol(path[0].c_str(), nullptr, 10);
      if (count < 1 || count > 2000)
          return RESTERR(req, HTTP_BAD_REQUEST, "Header count out of range: " + path[0]);
  
      string hashStr = path[1];
      uint256 hash;
      if (!ParseHashStr(hashStr, hash))
          return RESTERR(req, HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);
  
      std::vector<const CBlockIndex *> headers;
      headers.reserve(count);
      {
          LOCK(cs_main);
          BlockMap::const_iterator it = mapBlockIndex.find(hash);
          const CBlockIndex *pindex = (it != mapBlockIndex.end()) ? it->second : nullptr;
          while (pindex != nullptr && chainActive.Contains(pindex)) {
              headers.push_back(pindex);
              if (headers.size() == (unsigned long)count)
                  break;
              pindex = chainActive.Next(pindex);
          }
      }
  
      CDataStream ssHeader(SER_NETWORK, PROTOCOL_VERSION);
      for (const CBlockIndex *pindex : headers) {
          ssHeader << pindex->GetBlockHeader();
      }
  
      switch (rf) {
      case RF_BINARY: {
          string binaryHeader = ssHeader.str();
          req->WriteHeader("Content-Type", "application/octet-stream");
          req->WriteReply(HTTP_OK, binaryHeader);
          return true;
      }
  
      case RF_HEX: {
          string strHex = HexStr(ssHeader.begin(), ssHeader.end()) + "\n";
          req->WriteHeader("Content-Type", "text/plain");
          req->WriteReply(HTTP_OK, strHex);
          return true;
      }
  
      case RF_JSON: {
          UniValue jsonHeaders(UniValue::VARR);
          for (const CBlockIndex *pindex : headers) {
              jsonHeaders.push_back(blockheaderToJSON(pindex));
          }
          string strJSON = jsonHeaders.write() + "\n";
          req->WriteHeader("Content-Type", "application/json");
          req->WriteReply(HTTP_OK, strJSON);
          return true;
      }
  
      default: {
          return RESTERR(req, HTTP_NOT_FOUND, "output format not found (available: .bin, .hex)");
      }
      }
  
      // not reached
      return true; // continue to process further HTTP reqs on this cxn
  }
  
  static bool rest_block(HTTPRequest* req,
                         const std::string& strURIPart,
                         bool showTxDetails)
  {
      if (!CheckWarmup(req))
          return false;
      vector<string> params;
      const RetFormat rf = ParseDataFormat(params, strURIPart);
  
      string hashStr = params[0];
      uint256 hash;
      if (!ParseHashStr(hashStr, hash))
          return RESTERR(req, HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);
  
      CBlock block;
      CBlockIndex* pblockindex = nullptr;
      {
          LOCK(cs_main);
          if (mapBlockIndex.count(hash) == 0)
              return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not found");
  
          pblockindex = mapBlockIndex[hash];
          if (fHavePruned && !(pblockindex->nStatus & BLOCK_HAVE_DATA) && pblockindex->nTx > 0)
              return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not available (pruned data)");
  
          if (!ReadBlockFromDisk(block, pblockindex, Params().GetConsensus()))
              return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not found");
      }
  
      CDataStream ssBlock(SER_NETWORK, PROTOCOL_VERSION);
      ssBlock << block;
  
      switch (rf) {
      case RF_BINARY: {
          string binaryBlock = ssBlock.str();
          req->WriteHeader("Content-Type", "application/octet-stream");
          req->WriteReply(HTTP_OK, binaryBlock);
          return true;
      }
  
      case RF_HEX: {
          string strHex = HexStr(ssBlock.begin(), ssBlock.end()) + "\n";
          req->WriteHeader("Content-Type", "text/plain");
          req->WriteReply(HTTP_OK, strHex);
          return true;
      }
  
      case RF_JSON: {
          UniValue objBlock = blockToJSON(block, pblockindex, showTxDetails);
          string strJSON = objBlock.write() + "\n";
          req->WriteHeader("Content-Type", "application/json");
          req->WriteReply(HTTP_OK, strJSON);
          return true;
      }
  
      default: {
          return RESTERR(req, HTTP_NOT_FOUND, "output format not found (available: " + AvailableDataFormatsString() + ")");
      }
      }
  
      // not reached
      return true; // continue to process further HTTP reqs on this cxn
  }
  
  static bool rest_block_extended(HTTPRequest* req, const std::string& strURIPart)
  {
      return rest_block(req, strURIPart, true);
  }
  
  static bool rest_block_notxdetails(HTTPRequest* req, const std::string& strURIPart)
  {
      return rest_block(req, strURIPart, false);
  }
  
  // A bit of a hack - dependency on a function defined in rpc/blockchain.cpp
  UniValue getblockchaininfo(const JSONRPCRequest& request);
  
  static bool rest_chaininfo(HTTPRequest* req, const std::string& strURIPart)
  {
      if (!CheckWarmup(req))
          return false;
      vector<string> params;
      const RetFormat rf = ParseDataFormat(params, strURIPart);
  
      switch (rf) {
      case RF_JSON: {
          JSONRPCRequest jsonRequest;
          jsonRequest.params = UniValue(UniValue::VARR);
          UniValue chainInfoObject = getblockchaininfo(jsonRequest);
  
          string strJSON = chainInfoObject.write() + "\n";
          req->WriteHeader("Content-Type", "application/json");
          req->WriteReply(HTTP_OK, strJSON);
          return true;
      }
      default: {
          return RESTERR(req, HTTP_NOT_FOUND, "output format not found (available: json)");
      }
      }
  
      // not reached
      return true; // continue to process further HTTP reqs on this cxn
  }
  
  static bool rest_mempool_info(HTTPRequest* req, const std::string& strURIPart)
  {
      if (!CheckWarmup(req))
          return false;
      vector<string> params;
      const RetFormat rf = ParseDataFormat(params, strURIPart);
  
      switch (rf) {
      case RF_JSON: {
          UniValue mempoolInfoObject = mempoolInfoToJSON();
  
          string strJSON = mempoolInfoObject.write() + "\n";
          req->WriteHeader("Content-Type", "application/json");
          req->WriteReply(HTTP_OK, strJSON);
          return true;
      }
      default: {
          return RESTERR(req, HTTP_NOT_FOUND, "output format not found (available: json)");
      }
      }
  
      // not reached
      return true; // continue to process further HTTP reqs on this cxn
  }
  
  static bool rest_mempool_contents(HTTPRequest* req, const std::string& strURIPart)
  {
      if (!CheckWarmup(req))
          return false;
      vector<string> params;
      const RetFormat rf = ParseDataFormat(params, strURIPart);
  
      switch (rf) {
      case RF_JSON: {
          UniValue mempoolObject = mempoolToJSON(true);
  
          string strJSON = mempoolObject.write() + "\n";
          req->WriteHeader("Content-Type", "application/json");
          req->WriteReply(HTTP_OK, strJSON);
          return true;
      }
      default: {
          return RESTERR(req, HTTP_NOT_FOUND, "output format not found (available: json)");
      }
      }
  
      // not reached
      return true; // continue to process further HTTP reqs on this cxn
  }
  
  static bool rest_tx(HTTPRequest* req, const std::string& strURIPart)
  {
      if (!CheckWarmup(req))
          return false;
      vector<string> params;
      const RetFormat rf = ParseDataFormat(params, strURIPart);
  
      string hashStr = params[0];
      uint256 hash;
      if (!ParseHashStr(hashStr, hash))
          return RESTERR(req, HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);
  
      CTransaction tx;
      uint256 hashBlock = uint256();
      if (!GetTransaction(hash, tx, Params().GetConsensus(), hashBlock, true))
          return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not found");
  
      CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
      ssTx << tx;
  
      switch (rf) {
      case RF_BINARY: {
          string binaryTx = ssTx.str();
          req->WriteHeader("Content-Type", "application/octet-stream");
          req->WriteReply(HTTP_OK, binaryTx);
          return true;
      }
  
      case RF_HEX: {
          string strHex = HexStr(ssTx.begin(), ssTx.end()) + "\n";
          req->WriteHeader("Content-Type", "text/plain");
          req->WriteReply(HTTP_OK, strHex);
          return true;
      }
  
      case RF_JSON: {
          UniValue objTx(UniValue::VOBJ);
          TxToJSON(tx, hashBlock, objTx);
          string strJSON = objTx.write() + "\n";
          req->WriteHeader("Content-Type", "application/json");
          req->WriteReply(HTTP_OK, strJSON);
          return true;
      }
  
      default: {
          return RESTERR(req, HTTP_NOT_FOUND, "output format not found (available: " + AvailableDataFormatsString() + ")");
      }
      }
  
      // not reached
      return true; // continue to process further HTTP reqs on this cxn
  }
  
  static bool rest_getutxos(HTTPRequest* req, const std::string& strURIPart)
  {
      if (!CheckWarmup(req))
          return false;
      vector<string> params;
      enum RetFormat rf = ParseDataFormat(params, strURIPart);
  
      vector<string> uriParts;
      if (params.size() > 0 && params[0].length() > 1)
      {
          std::string strUriParams = params[0].substr(1);
          boost::split(uriParts, strUriParams, boost::is_any_of("/"));
      }
  
      // throw exception in case of a empty request
      std::string strRequestMutable = req->ReadBody();
      if (strRequestMutable.length() == 0 && uriParts.size() == 0)
          return RESTERR(req, HTTP_INTERNAL_SERVER_ERROR, "Error: empty request");
  
      bool fInputParsed = false;
      bool fCheckMemPool = false;
      vector<COutPoint> vOutPoints;
  
      // parse/deserialize input
      // input-format = output-format, rest/getutxos/bin requires binary input, gives binary output, ...
  
      if (uriParts.size() > 0)
      {
  
          //inputs is sent over URI scheme (/rest/getutxos/checkmempool/txid1-n/txid2-n/...)
          if (uriParts.size() > 0 && uriParts[0] == "checkmempool")
              fCheckMemPool = true;
  
          for (size_t i = (fCheckMemPool) ? 1 : 0; i < uriParts.size(); i++)
          {
              uint256 txid;
              int32_t nOutput;
              std::string strTxid = uriParts[i].substr(0, uriParts[i].find("-"));
              std::string strOutput = uriParts[i].substr(uriParts[i].find("-")+1);
  
              if (!ParseInt32(strOutput, &nOutput) || !IsHex(strTxid))
                  return RESTERR(req, HTTP_INTERNAL_SERVER_ERROR, "Parse error");
  
              txid.SetHex(strTxid);
              vOutPoints.push_back(COutPoint(txid, (uint32_t)nOutput));
          }
  
          if (vOutPoints.size() > 0)
              fInputParsed = true;
          else
              return RESTERR(req, HTTP_INTERNAL_SERVER_ERROR, "Error: empty request");
      }
  
      switch (rf) {
      case RF_HEX: {
          // convert hex to bin, continue then with bin part
          std::vector<unsigned char> strRequestV = ParseHex(strRequestMutable);
          strRequestMutable.assign(strRequestV.begin(), strRequestV.end());
      }
      // fall through
      case RF_BINARY: {
          try {
              //deserialize only if user sent a request
              if (strRequestMutable.size() > 0)
              {
                  if (fInputParsed) //don't allow sending input over URI and HTTP RAW DATA
                      return RESTERR(req, HTTP_INTERNAL_SERVER_ERROR, "Combination of URI scheme inputs and raw post data is not allowed");
  
                  CDataStream oss(SER_NETWORK, PROTOCOL_VERSION);
                  oss << strRequestMutable;
                  oss >> fCheckMemPool;
                  oss >> vOutPoints;
              }
          } catch (const std::ios_base::failure& e) {
              // abort in case of unreadable binary data
              return RESTERR(req, HTTP_INTERNAL_SERVER_ERROR, "Parse error");
          }
          break;
      }
  
      case RF_JSON: {
          if (!fInputParsed)
              return RESTERR(req, HTTP_INTERNAL_SERVER_ERROR, "Error: empty request");
          break;
      }
      default: {
          return RESTERR(req, HTTP_NOT_FOUND, "output format not found (available: " + AvailableDataFormatsString() + ")");
      }
      }
  
      // limit max outpoints
      if (vOutPoints.size() > MAX_GETUTXOS_OUTPOINTS)
          return RESTERR(req, HTTP_INTERNAL_SERVER_ERROR, strprintf("Error: max outpoints exceeded (max: %d, tried: %d)", MAX_GETUTXOS_OUTPOINTS, vOutPoints.size()));
  
      // check spentness and form a bitmap (as well as a JSON capable human-readble string representation)
      vector<unsigned char> bitmap;
      vector<CCoin> outs;
      std::string bitmapStringRepresentation;
      std::vector<bool> hits;
      bitmap.resize((vOutPoints.size() + 7) / 8);
      {
          LOCK2(cs_main, mempool.cs);
  
          CCoinsView viewDummy;
          CCoinsViewCache view(&viewDummy);
  
          CCoinsViewCache& viewChain = *pcoinsTip;
          CCoinsViewMemPool viewMempool(&viewChain, mempool);
  
          if (fCheckMemPool)
              view.SetBackend(viewMempool); // switch cache backend to db+mempool in case user likes to query mempool
  
          for (size_t i = 0; i < vOutPoints.size(); i++) {
              bool hit = false;
              Coin coin;
              if (view.GetCoin(vOutPoints[i], coin) && !mempool.isSpent(vOutPoints[i])) {
                  hit = true;
                  outs.emplace_back(std::move(coin));
              }
  
              hits.push_back(hit);
              bitmapStringRepresentation.append(hit ? "1" : "0"); // form a binary string representation (human-readable for json output)
              bitmap[i / 8] |= ((uint8_t)hit) << (i % 8);
          }
      }
  
      switch (rf) {
      case RF_BINARY: {
          // serialize data
          // use exact same output as mentioned in Bip64
          CDataStream ssGetUTXOResponse(SER_NETWORK, PROTOCOL_VERSION);
          ssGetUTXOResponse << chainActive.Height() << chainActive.Tip()->GetBlockHash() << bitmap << outs;
          string ssGetUTXOResponseString = ssGetUTXOResponse.str();
  
          req->WriteHeader("Content-Type", "application/octet-stream");
          req->WriteReply(HTTP_OK, ssGetUTXOResponseString);
          return true;
      }
  
      case RF_HEX: {
          CDataStream ssGetUTXOResponse(SER_NETWORK, PROTOCOL_VERSION);
          ssGetUTXOResponse << chainActive.Height() << chainActive.Tip()->GetBlockHash() << bitmap << outs;
          string strHex = HexStr(ssGetUTXOResponse.begin(), ssGetUTXOResponse.end()) + "\n";
  
          req->WriteHeader("Content-Type", "text/plain");
          req->WriteReply(HTTP_OK, strHex);
          return true;
      }
  
      case RF_JSON: {
          UniValue objGetUTXOResponse(UniValue::VOBJ);
  
          // pack in some essentials
          // use more or less the same output as mentioned in Bip64
          objGetUTXOResponse.pushKV("chainHeight", chainActive.Height());
          objGetUTXOResponse.pushKV("chaintipHash", chainActive.Tip()->GetBlockHash().GetHex());
          objGetUTXOResponse.pushKV("bitmap", bitmapStringRepresentation);
  
          UniValue utxos(UniValue::VARR);
          for (const CCoin& coin : outs) {
              UniValue utxo(UniValue::VOBJ);
              utxo.pushKV("height", (int32_t)coin.nHeight);
              utxo.pushKV("value", ValueFromAmount(coin.out.nValue));
  
              // include the script in a json output
              UniValue o(UniValue::VOBJ);
              ScriptPubKeyToJSON(coin.out.scriptPubKey, o, true);
              utxo.pushKV("scriptPubKey", o);
              utxos.push_back(utxo);
          }
          objGetUTXOResponse.pushKV("utxos", utxos);
  
          // return json string
          string strJSON = objGetUTXOResponse.write() + "\n";
          req->WriteHeader("Content-Type", "application/json");
          req->WriteReply(HTTP_OK, strJSON);
          return true;
      }
      default: {
          return RESTERR(req, HTTP_NOT_FOUND, "output format not found (available: " + AvailableDataFormatsString() + ")");
      }
      }
  
      // not reached
      return true; // continue to process further HTTP reqs on this cxn
  }
  
  static const struct {
      const char* prefix;
      bool (*handler)(HTTPRequest* req, const std::string& strReq);
  } uri_prefixes[] = {
        {"/rest/tx/", rest_tx},
        {"/rest/block/notxdetails/", rest_block_notxdetails},
        {"/rest/block/", rest_block_extended},
        {"/rest/chaininfo", rest_chaininfo},
        {"/rest/mempool/info", rest_mempool_info},
        {"/rest/mempool/contents", rest_mempool_contents},
        {"/rest/headers/", rest_headers},
        {"/rest/getutxos", rest_getutxos},
  };
  
  bool StartREST()
  {
      for (unsigned int i = 0; i < ARRAYLEN(uri_prefixes); i++)
          RegisterHTTPHandler(uri_prefixes[i].prefix, false, uri_prefixes[i].handler);
      return true;
  }
  
  void InterruptREST()
  {
  }
  
  void StopREST()
  {
      for (unsigned int i = 0; i < ARRAYLEN(uri_prefixes); i++)
          UnregisterHTTPHandler(uri_prefixes[i].prefix, false);
  }
  