Merge #8811: rpc: Add support for JSON-RPC named arguments

4e7e2e1 Update RPC argument names (John Newbery)
481f289 rpc: Named argument support for bitcoin-cli (Wladimir J. van der Laan)
9adb4e1 rpc: Argument name consistency (Wladimir J. van der Laan)
8d713f7 rpc: Named arguments for rawtransaction calls (Wladimir J. van der Laan)
37a166f rpc: Named arguments for wallet calls (Wladimir J. van der Laan)
78b684f rpc: Named arguments for mining calls (Wladimir J. van der Laan)
b8ebc59 rpc: Named arguments for net calls (Wladimir J. van der Laan)
2ca9dcd test: Add test for RPC named arguments (Wladimir J. van der Laan)
fba1a61 rpc: Named arguments for misc calls (Wladimir J. van der Laan)
286ec08 rpc: Add 'echo' call for testing (Wladimir J. van der Laan)
495eb44 rpc: Named arguments for blockchain calls (Wladimir J. van der Laan)
6f1c76a rpc: Support named arguments (Wladimir J. van der Laan)
5865d41 authproxy: Add support for RPC named arguments (Wladimir J. van der Laan)

1 files changed, 56 insertions, 9 deletions

diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index 8a223d8aa..1b94e1007 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -26,6 +26,7 @@
 #include <boost/algorithm/string/case_conv.hpp> // for to_upper()
 
 #include <memory> // for unique_ptr
+#include <unordered_map>
 
 using namespace RPCServer;
 using namespace std;
@@ -268,11 +269,11 @@ UniValue stop(const JSONRPCRequest& jsonRequest)
  * Call Table
  */
 static const CRPCCommand vRPCCommands[] =
-{ //  category              name                      actor (function)         okSafeMode
-  //  --------------------- ------------------------  -----------------------  ----------
+{ //  category              name                      actor (function)         okSafe argNames
+  //  --------------------- ------------------------  -----------------------  ------ ----------
     /* Overall control/query calls */
-    { "control",            "help",                   &help,                   true  },
-    { "control",            "stop",                   &stop,                   true  },
+    { "control",            "help",                   &help,                   true,  {"command"}  },
+    { "control",            "stop",                   &stop,                   true,  {}  },
 };
 
 CRPCTable::CRPCTable()
@@ -379,12 +380,12 @@ void JSONRPCRequest::parse(const UniValue& valRequest)
 
     // Parse params
     UniValue valParams = find_value(request, "params");
-    if (valParams.isArray())
-        params = valParams.get_array();
+    if (valParams.isArray() || valParams.isObject())
+        params = valParams;
     else if (valParams.isNull())
         params = UniValue(UniValue::VARR);
     else
-        throw JSONRPCError(RPC_INVALID_REQUEST, "Params must be an array");
+        throw JSONRPCError(RPC_INVALID_REQUEST, "Params must be an array or object");
 }
 
 static UniValue JSONRPCExecOne(const UniValue& req)
@@ -420,6 +421,48 @@ std::string JSONRPCExecBatch(const UniValue& vReq)
     return ret.write() + "\n";
 }
 
+/**
+ * Process named arguments into a vector of positional arguments, based on the
+ * passed-in specification for the RPC call's arguments.
+ */
+static inline JSONRPCRequest transformNamedArguments(const JSONRPCRequest& in, const std::vector<std::string>& argNames)
+{
+    JSONRPCRequest out = in;
+    out.params = UniValue(UniValue::VARR);
+    // Build a map of parameters, and remove ones that have been processed, so that we can throw a focused error if
+    // there is an unknown one.
+    const std::vector<std::string>& keys = in.params.getKeys();
+    const std::vector<UniValue>& values = in.params.getValues();
+    std::unordered_map<std::string, const UniValue*> argsIn;
+    for (size_t i=0; i<keys.size(); ++i) {
+        argsIn[keys[i]] = &values[i];
+    }
+    // Process expected parameters.
+    int hole = 0;
+    for (const std::string &argName: argNames) {
+        auto fr = argsIn.find(argName);
+        if (fr != argsIn.end()) {
+            for (int i = 0; i < hole; ++i) {
+                // Fill hole between specified parameters with JSON nulls,
+                // but not at the end (for backwards compatibility with calls
+                // that act based on number of specified parameters).
+                out.params.push_back(UniValue());
+            }
+            hole = 0;
+            out.params.push_back(*fr->second);
+            argsIn.erase(fr);
+        } else {
+            hole += 1;
+        }
+    }
+    // If there are still arguments in the argsIn map, this is an error.
+    if (!argsIn.empty()) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Unknown named parameter " + argsIn.begin()->first);
+    }
+    // Return request with named arguments transformed to positional arguments
+    return out;
+}
+
 UniValue CRPCTable::execute(const JSONRPCRequest &request) const
 {
     // Return immediately if in warmup
@@ -438,8 +481,12 @@ UniValue CRPCTable::execute(const JSONRPCRequest &request) const
 
     try
     {
-        // Execute
-        return pcmd->actor(request);
+        // Execute, convert arguments to array if necessary
+        if (request.params.isObject()) {
+            return pcmd->actor(transformNamedArguments(request, pcmd->argNames));
+        } else {
+            return pcmd->actor(request);
+        }
     }
     catch (const std::exception& e)
     {