aboutsummaryrefslogtreecommitdiff
path: root/src/rest.cpp
blob: 55756ecfdf312ed88fb1c1cfd918b283ff8d9f3b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2018 The Bitcoin Core 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 <core_io.h>
#include <httpserver.h>
#include <index/txindex.h>
#include <node/context.h>
#include <primitives/block.h>
#include <primitives/transaction.h>
#include <rpc/blockchain.h>
#include <rpc/protocol.h>
#include <rpc/server.h>
#include <streams.h>
#include <sync.h>
#include <txmempool.h>
#include <util/check.h>
#include <util/strencodings.h>
#include <validation.h>
#include <version.h>

#include <boost/algorithm/string.hpp>

#include <univalue.h>

static const size_t MAX_GETUTXOS_OUTPOINTS = 15; //allow a max of 15 outpoints to be queried at once

enum class RetFormat {
    UNDEF,
    BINARY,
    HEX,
    JSON,
};

static const struct {
    RetFormat rf;
    const char* name;
} rf_names[] = {
      {RetFormat::UNDEF, ""},
      {RetFormat::BINARY, "bin"},
      {RetFormat::HEX, "hex"},
      {RetFormat::JSON, "json"},
};

struct CCoin {
    uint32_t nHeight;
    CTxOut out;

    ADD_SERIALIZE_METHODS;

    CCoin() : nHeight(0) {}
    explicit 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);
    }
};

static bool RESTERR(HTTPRequest* req, enum HTTPStatusCode status, std::string message)
{
    req->WriteHeader("Content-Type", "text/plain");
    req->WriteReply(status, message + "\r\n");
    return false;
}

/**
 * Get the node context mempool.
 *
 * Set the HTTP error and return nullptr if node context
 * mempool is not found.
 *
 * @param[in]  req the HTTP request
 * return pointer to the mempool or nullptr if no mempool found
 */
static CTxMemPool* GetMemPool(HTTPRequest* req)
{
    if (!g_rpc_node || !g_rpc_node->mempool) {
        RESTERR(req, HTTP_NOT_FOUND, "Mempool disabled or instance not found");
        return nullptr;
    }
    return g_rpc_node->mempool;
}

static RetFormat ParseDataFormat(std::string& param, const std::string& strReq)
{
    const std::string::size_type pos = strReq.rfind('.');
    if (pos == std::string::npos)
    {
        param = strReq;
        return rf_names[0].rf;
    }

    param = strReq.substr(0, pos);
    const std::string suff(strReq, pos + 1);

    for (unsigned int i = 0; i < ARRAYLEN(rf_names); i++)
        if (suff == rf_names[i].name)
            return rf_names[i].rf;

    /* If no suffix is found, return original string.  */
    param = strReq;
    return rf_names[0].rf;
}

static std::string AvailableDataFormatsString()
{
    std::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 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;
    std::string param;
    const RetFormat rf = ParseDataFormat(param, strURIPart);
    std::vector<std::string> path;
    boost::split(path, param, 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]);

    std::string hashStr = path[1];
    uint256 hash;
    if (!ParseHashStr(hashStr, hash))
        return RESTERR(req, HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);

    const CBlockIndex* tip = nullptr;
    std::vector<const CBlockIndex *> headers;
    headers.reserve(count);
    {
        LOCK(cs_main);
        tip = ::ChainActive().Tip();
        const CBlockIndex* pindex = LookupBlockIndex(hash);
        while (pindex != nullptr && ::ChainActive().Contains(pindex)) {
            headers.push_back(pindex);
            if (headers.size() == (unsigned long)count)
                break;
            pindex = ::ChainActive().Next(pindex);
        }
    }

    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);
        return true;
    }
    case RetFormat::JSON: {
        UniValue jsonHeaders(UniValue::VARR);
        for (const CBlockIndex *pindex : headers) {
            jsonHeaders.push_back(blockheaderToJSON(tip, pindex));
        }
        std::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)");
    }
    }
}

static bool rest_block(HTTPRequest* req,
                       const std::string& strURIPart,
                       bool showTxDetails)
{
    if (!CheckWarmup(req))
        return false;
    std::string hashStr;
    const RetFormat rf = ParseDataFormat(hashStr, strURIPart);

    uint256 hash;
    if (!ParseHashStr(hashStr, hash))
        return RESTERR(req, HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);

    CBlock block;
    CBlockIndex* pblockindex = nullptr;
    CBlockIndex* tip = nullptr;
    {
        LOCK(cs_main);
        tip = ::ChainActive().Tip();
        pblockindex = LookupBlockIndex(hash);
        if (!pblockindex) {
            return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not found");
        }

        if (IsBlockPruned(pblockindex))
            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");
    }

    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);
        return true;
    }

    case RetFormat::JSON: {
        UniValue objBlock = blockToJSON(block, tip, pblockindex, showTxDetails);
        std::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() + ")");
    }
    }
}

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;
    std::string param;
    const RetFormat rf = ParseDataFormat(param, strURIPart);

    switch (rf) {
    case RetFormat::JSON: {
        JSONRPCRequest jsonRequest;
        jsonRequest.params = UniValue(UniValue::VARR);
        UniValue chainInfoObject = getblockchaininfo(jsonRequest);
        std::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)");
    }
    }
}

static bool rest_mempool_info(HTTPRequest* req, const std::string& strURIPart)
{
    if (!CheckWarmup(req))
        return false;
    const CTxMemPool* mempool = GetMemPool(req);
    if (!mempool) return false;
    std::string param;
    const RetFormat rf = ParseDataFormat(param, strURIPart);

    switch (rf) {
    case RetFormat::JSON: {
        UniValue mempoolInfoObject = MempoolInfoToJSON(*mempool);

        std::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)");
    }
    }
}

static bool rest_mempool_contents(HTTPRequest* req, const std::string& strURIPart)
{
    if (!CheckWarmup(req)) return false;
    const CTxMemPool* mempool = GetMemPool(req);
    if (!mempool) return false;
    std::string param;
    const RetFormat rf = ParseDataFormat(param, strURIPart);

    switch (rf) {
    case RetFormat::JSON: {
        UniValue mempoolObject = MempoolToJSON(*mempool, true);

        std::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)");
    }
    }
}

static bool rest_tx(HTTPRequest* req, const std::string& strURIPart)
{
    if (!CheckWarmup(req))
        return false;
    std::string hashStr;
    const RetFormat rf = ParseDataFormat(hashStr, strURIPart);

    uint256 hash;
    if (!ParseHashStr(hashStr, hash))
        return RESTERR(req, HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);

    if (g_txindex) {
        g_txindex->BlockUntilSyncedToCurrentChain();
    }

    CTransactionRef tx;
    uint256 hashBlock = uint256();
    if (!GetTransaction(hash, tx, Params().GetConsensus(), hashBlock))
        return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not found");

    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);
        return true;
    }

    case RetFormat::JSON: {
        UniValue objTx(UniValue::VOBJ);
        TxToUniv(*tx, hashBlock, objTx);
        std::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() + ")");
    }
    }
}

static bool rest_getutxos(HTTPRequest* req, const std::string& strURIPart)
{
    if (!CheckWarmup(req))
        return false;
    std::string param;
    const RetFormat rf = ParseDataFormat(param, strURIPart);

    std::vector<std::string> uriParts;
    if (param.length() > 1)
    {
        std::string strUriParams = param.substr(1);
        boost::split(uriParts, strUriParams, boost::is_any_of("/"));
    }

    // throw exception in case of an empty request
    std::string strRequestMutable = req->ReadBody();
    if (strRequestMutable.length() == 0 && uriParts.size() == 0)
        return RESTERR(req, HTTP_BAD_REQUEST, "Error: empty request");

    bool fInputParsed = false;
    bool fCheckMemPool = false;
    std::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[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_BAD_REQUEST, "Parse error");

            txid.SetHex(strTxid);
            vOutPoints.push_back(COutPoint(txid, (uint32_t)nOutput));
        }

        if (vOutPoints.size() > 0)
            fInputParsed = true;
        else
            return RESTERR(req, HTTP_BAD_REQUEST, "Error: empty request");
    }

    switch (rf) {
    case RetFormat::HEX: {
        // convert hex to bin, continue then with bin part
        std::vector<unsigned char> strRequestV = ParseHex(strRequestMutable);
        strRequestMutable.assign(strRequestV.begin(), strRequestV.end());
    }

    case RetFormat::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_BAD_REQUEST, "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&) {
            // abort in case of unreadable binary data
            return RESTERR(req, HTTP_BAD_REQUEST, "Parse error");
        }
        break;
    }

    case RetFormat::JSON: {
        if (!fInputParsed)
            return RESTERR(req, HTTP_BAD_REQUEST, "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_BAD_REQUEST, 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-readable string representation)
    std::vector<unsigned char> bitmap;
    std::vector<CCoin> outs;
    std::string bitmapStringRepresentation;
    std::vector<bool> hits;
    bitmap.resize((vOutPoints.size() + 7) / 8);
    {
        auto process_utxos = [&vOutPoints, &outs, &hits](const CCoinsView& view, const CTxMemPool& mempool) {
            for (const COutPoint& vOutPoint : vOutPoints) {
                Coin coin;
                bool hit = !mempool.isSpent(vOutPoint) && view.GetCoin(vOutPoint, coin);
                hits.push_back(hit);
                if (hit) outs.emplace_back(std::move(coin));
            }
        };

        if (fCheckMemPool) {
            const CTxMemPool* mempool = GetMemPool(req);
            if (!mempool) return false;
            // use db+mempool as cache backend in case user likes to query mempool
            LOCK2(cs_main, mempool->cs);
            CCoinsViewCache& viewChain = ::ChainstateActive().CoinsTip();
            CCoinsViewMemPool viewMempool(&viewChain, *mempool);
            process_utxos(viewMempool, *mempool);
        } else {
            LOCK(cs_main);  // no need to lock mempool!
            process_utxos(::ChainstateActive().CoinsTip(), CTxMemPool());
        }

        for (size_t i = 0; i < hits.size(); ++i) {
            const bool hit = hits[i];
            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 RetFormat::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;
        std::string ssGetUTXOResponseString = ssGetUTXOResponse.str();

        req->WriteHeader("Content-Type", "application/octet-stream");
        req->WriteReply(HTTP_OK, ssGetUTXOResponseString);
        return true;
    }

    case RetFormat::HEX: {
        CDataStream ssGetUTXOResponse(SER_NETWORK, PROTOCOL_VERSION);
        ssGetUTXOResponse << ::ChainActive().Height() << ::ChainActive().Tip()->GetBlockHash() << bitmap << outs;
        std::string strHex = HexStr(ssGetUTXOResponse.begin(), ssGetUTXOResponse.end()) + "\n";

        req->WriteHeader("Content-Type", "text/plain");
        req->WriteReply(HTTP_OK, strHex);
        return true;
    }

    case RetFormat::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);
            ScriptPubKeyToUniv(coin.out.scriptPubKey, o, true);
            utxo.pushKV("scriptPubKey", o);
            utxos.push_back(utxo);
        }
        objGetUTXOResponse.pushKV("utxos", utxos);

        // return json string
        std::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() + ")");
    }
    }
}

static bool rest_blockhash_by_height(HTTPRequest* req,
                       const std::string& str_uri_part)
{
    if (!CheckWarmup(req)) return false;
    std::string height_str;
    const RetFormat rf = ParseDataFormat(height_str, str_uri_part);

    int32_t blockheight;
    if (!ParseInt32(height_str, &blockheight) || blockheight < 0) {
        return RESTERR(req, HTTP_BAD_REQUEST, "Invalid height: " + SanitizeString(height_str));
    }

    CBlockIndex* pblockindex = nullptr;
    {
        LOCK(cs_main);
        if (blockheight > ::ChainActive().Height()) {
            return RESTERR(req, HTTP_NOT_FOUND, "Block height out of range");
        }
        pblockindex = ::ChainActive()[blockheight];
    }
    switch (rf) {
    case RetFormat::BINARY: {
        CDataStream ss_blockhash(SER_NETWORK, PROTOCOL_VERSION);
        ss_blockhash << pblockindex->GetBlockHash();
        req->WriteHeader("Content-Type", "application/octet-stream");
        req->WriteReply(HTTP_OK, ss_blockhash.str());
        return true;
    }
    case RetFormat::HEX: {
        req->WriteHeader("Content-Type", "text/plain");
        req->WriteReply(HTTP_OK, pblockindex->GetBlockHash().GetHex() + "\n");
        return true;
    }
    case RetFormat::JSON: {
        req->WriteHeader("Content-Type", "application/json");
        UniValue resp = UniValue(UniValue::VOBJ);
        resp.pushKV("blockhash", pblockindex->GetBlockHash().GetHex());
        req->WriteReply(HTTP_OK, resp.write() + "\n");
        return true;
    }
    default: {
        return RESTERR(req, HTTP_NOT_FOUND, "output format not found (available: " + AvailableDataFormatsString() + ")");
    }
    }
}

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},
      {"/rest/blockhashbyheight/", rest_blockhash_by_height},
};

void StartREST()
{
    for (unsigned int i = 0; i < ARRAYLEN(uri_prefixes); i++)
        RegisterHTTPHandler(uri_prefixes[i].prefix, false, uri_prefixes[i].handler);
}

void InterruptREST()
{
}

void StopREST()
{
    for (unsigned int i = 0; i < ARRAYLEN(uri_prefixes); i++)
        UnregisterHTTPHandler(uri_prefixes[i].prefix, false);
}