Implement REST mempool API, add test and documentation.

doc/REST-interface.md

@@ -77,6 +77,20 @@ $ curl localhost:18332/rest/getutxos/checkmempool/b2cdfd7b89def827ff8af7cd9bff76
 }
 ```
 
+####Memory pool
+`GET /rest/mempool/info.json`
+
+Returns various information about the TX mempool.
+Only supports JSON as output format.
+* size : (numeric) the number of transactions in the TX mempool
+* bytes : (numeric) size of the TX mempool in bytes
+* usage : (numeric) total TX mempool memory usage
+
+`GET /rest/mempool/contents.json`
+
+Returns transactions in the TX mempool.
+Only supports JSON as output format.
+
 Risks
 -------------
 Running a web browser on the same node with a REST enabled bitcoind can be a risk. Accessing prepared XSS websites could read out tx/block data of your node by placing links like `<script src="http://127.0.0.1:8332/rest/tx/1234567890.json">` which might break the nodes privacy.

qa/rpc-tests/rest.py

@@ -292,6 +292,19 @@ class RESTTest (BitcoinTestFramework):
         txs.append(self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), 11))
         self.sync_all()
 
+        # check that there are exactly 3 transactions in the TX memory pool before generating the block
+        json_string = http_get_call(url.hostname, url.port, '/rest/mempool/info'+self.FORMAT_SEPARATOR+'json')
+        json_obj = json.loads(json_string)
+        assert_equal(json_obj['size'], 3)
+        # the size of the memory pool should be greater than 3x ~100 bytes
+        assert_greater_than(json_obj['bytes'], 300)
+
+        # check that there are our submitted transactions in the TX memory pool
+        json_string = http_get_call(url.hostname, url.port, '/rest/mempool/contents'+self.FORMAT_SEPARATOR+'json')
+        json_obj = json.loads(json_string)
+        for tx in txs:
+            assert_equal(tx in json_obj, True)
+
         # now mine the transactions
         newblockhash = self.nodes[1].generate(1)
         self.sync_all()

src/rest.cpp

@@ -65,6 +65,8 @@ public:
 
 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);
 
@@ -293,6 +295,58 @@ static bool rest_chaininfo(AcceptedConnection* conn,
     return true; // continue to process further HTTP reqs on this cxn
 }
 
+static bool rest_mempool_info(AcceptedConnection* conn,
+                              const std::string& strURIPart,
+                              const std::string& strRequest,
+                              const std::map<std::string, std::string>& mapHeaders,
+                              bool fRun)
+{
+    vector<string> params;
+    const RetFormat rf = ParseDataFormat(params, strURIPart);
+
+    switch (rf) {
+    case RF_JSON: {
+        UniValue mempoolInfoObject = mempoolInfoToJSON();
+
+        string strJSON = mempoolInfoObject.write() + "\n";
+        conn->stream() << HTTPReply(HTTP_OK, strJSON, fRun) << std::flush;
+        return true;
+    }
+    default: {
+        throw RESTERR(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(AcceptedConnection* conn,
+                                  const std::string& strURIPart,
+                                  const std::string& strRequest,
+                                  const std::map<std::string, std::string>& mapHeaders,
+                                  bool fRun)
+{
+    vector<string> params;
+    const RetFormat rf = ParseDataFormat(params, strURIPart);
+
+    switch (rf) {
+    case RF_JSON: {
+        UniValue mempoolObject = mempoolToJSON(true);
+
+        string strJSON = mempoolObject.write() + "\n";
+        conn->stream() << HTTPReply(HTTP_OK, strJSON, fRun) << std::flush;
+        return true;
+    }
+    default: {
+        throw RESTERR(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(AcceptedConnection* conn,
                     const std::string& strURIPart,
                     const std::string& strRequest,
@@ -553,6 +607,8 @@ static const struct {
       {"/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},
 };

src/rpcblockchain.cpp

@@ -175,45 +175,8 @@ UniValue getdifficulty(const UniValue& params, bool fHelp)
     return GetDifficulty();
 }
 
-
+UniValue mempoolToJSON(bool fVerbose = false)
-UniValue getrawmempool(const UniValue& params, bool fHelp)
 {
-    if (fHelp || params.size() > 1)
-        throw runtime_error(
-            "getrawmempool ( verbose )\n"
-            "\nReturns all transaction ids in memory pool as a json array of string transaction ids.\n"
-            "\nArguments:\n"
-            "1. verbose           (boolean, optional, default=false) true for a json object, false for array of transaction ids\n"
-            "\nResult: (for verbose = false):\n"
-            "[                     (json array of string)\n"
-            "  \"transactionid\"     (string) The transaction id\n"
-            "  ,...\n"
-            "]\n"
-            "\nResult: (for verbose = true):\n"
-            "{                           (json object)\n"
-            "  \"transactionid\" : {       (json object)\n"
-            "    \"size\" : n,             (numeric) transaction size in bytes\n"
-            "    \"fee\" : n,              (numeric) transaction fee in " + CURRENCY_UNIT + "\n"
-            "    \"time\" : n,             (numeric) local time transaction entered pool in seconds since 1 Jan 1970 GMT\n"
-            "    \"height\" : n,           (numeric) block height when transaction entered pool\n"
-            "    \"startingpriority\" : n, (numeric) priority when transaction entered pool\n"
-            "    \"currentpriority\" : n,  (numeric) transaction priority now\n"
-            "    \"depends\" : [           (array) unconfirmed transactions used as inputs for this transaction\n"
-            "        \"transactionid\",    (string) parent transaction id\n"
-            "       ... ]\n"
-            "  }, ...\n"
-            "}\n"
-            "\nExamples\n"
-            + HelpExampleCli("getrawmempool", "true")
-            + HelpExampleRpc("getrawmempool", "true")
-        );
-
-    LOCK(cs_main);
-
-    bool fVerbose = false;
-    if (params.size() > 0)
-        fVerbose = params[0].get_bool();
-
     if (fVerbose)
     {
         LOCK(mempool.cs);
@@ -261,6 +224,47 @@ UniValue getrawmempool(const UniValue& params, bool fHelp)
     }
 }
 
+UniValue getrawmempool(const UniValue& params, bool fHelp)
+{
+    if (fHelp || params.size() > 1)
+        throw runtime_error(
+            "getrawmempool ( verbose )\n"
+            "\nReturns all transaction ids in memory pool as a json array of string transaction ids.\n"
+            "\nArguments:\n"
+            "1. verbose           (boolean, optional, default=false) true for a json object, false for array of transaction ids\n"
+            "\nResult: (for verbose = false):\n"
+            "[                     (json array of string)\n"
+            "  \"transactionid\"     (string) The transaction id\n"
+            "  ,...\n"
+            "]\n"
+            "\nResult: (for verbose = true):\n"
+            "{                           (json object)\n"
+            "  \"transactionid\" : {       (json object)\n"
+            "    \"size\" : n,             (numeric) transaction size in bytes\n"
+            "    \"fee\" : n,              (numeric) transaction fee in " + CURRENCY_UNIT + "\n"
+            "    \"time\" : n,             (numeric) local time transaction entered pool in seconds since 1 Jan 1970 GMT\n"
+            "    \"height\" : n,           (numeric) block height when transaction entered pool\n"
+            "    \"startingpriority\" : n, (numeric) priority when transaction entered pool\n"
+            "    \"currentpriority\" : n,  (numeric) transaction priority now\n"
+            "    \"depends\" : [           (array) unconfirmed transactions used as inputs for this transaction\n"
+            "        \"transactionid\",    (string) parent transaction id\n"
+            "       ... ]\n"
+            "  }, ...\n"
+            "}\n"
+            "\nExamples\n"
+            + HelpExampleCli("getrawmempool", "true")
+            + HelpExampleRpc("getrawmempool", "true")
+        );
+
+    LOCK(cs_main);
+
+    bool fVerbose = false;
+    if (params.size() > 0)
+        fVerbose = params[0].get_bool();
+
+    return mempoolToJSON(fVerbose);
+}
+
 UniValue getblockhash(const UniValue& params, bool fHelp)
 {
     if (fHelp || params.size() != 1)
@@ -757,6 +761,16 @@ UniValue getchaintips(const UniValue& params, bool fHelp)
     return res;
 }
 
+UniValue mempoolInfoToJSON()
+{
+    UniValue ret(UniValue::VOBJ);
+    ret.push_back(Pair("size", (int64_t) mempool.size()));
+    ret.push_back(Pair("bytes", (int64_t) mempool.GetTotalTxSize()));
+    ret.push_back(Pair("usage", (int64_t) mempool.DynamicMemoryUsage()));
+
+    return ret;
+}
+
 UniValue getmempoolinfo(const UniValue& params, bool fHelp)
 {
     if (fHelp || params.size() != 0)
@@ -774,12 +788,7 @@ UniValue getmempoolinfo(const UniValue& params, bool fHelp)
             + HelpExampleRpc("getmempoolinfo", "")
         );
 
-    UniValue ret(UniValue::VOBJ);
+    return mempoolInfoToJSON();
-    ret.push_back(Pair("size", (int64_t) mempool.size()));
-    ret.push_back(Pair("bytes", (int64_t) mempool.GetTotalTxSize()));
-    ret.push_back(Pair("usage", (int64_t) mempool.DynamicMemoryUsage()));
-
-    return ret;
 }
 
 UniValue invalidateblock(const UniValue& params, bool fHelp)