Support API versioning

Builds/CMake/RippledCore.cmake

@@ -989,6 +989,7 @@ else ()
     src/test/rpc/TransactionEntry_test.cpp
     src/test/rpc/TransactionHistory_test.cpp
     src/test/rpc/ValidatorRPC_test.cpp
+    src/test/rpc/Version_test.cpp
     #[===============================[
        nounity, test sources:
          subdir: server

src/ripple/app/main/Application.cpp

@@ -61,6 +61,7 @@
 #include <ripple/protocol/STParsedJSON.h>
 #include <ripple/protocol/Protocol.h>
 #include <ripple/resource/Fees.h>
+#include <ripple/rpc/impl/RPCHelpers.h>
 #include <ripple/beast/asio/io_latency_probe.h>
 #include <ripple/beast/core/LexicalCast.h>
 
@@ -1583,7 +1584,8 @@ bool ApplicationImp::setup()
         Resource::Charge loadType = Resource::feeReferenceRPC;
         Resource::Consumer c;
         RPC::Context context { journal ("RPCHandler"), jvCommand, *this,
-            loadType, getOPs (), getLedgerMaster (), c, Role::ADMIN};
+            loadType, getOPs (), getLedgerMaster(), c, Role::ADMIN,
+            RPC::ApiMaximumSupportedVersion};
 
         Json::Value jvResult;
         RPC::doCommand (context, jvResult);

src/ripple/net/impl/RPCCall.cpp

@@ -36,6 +36,7 @@
 #include <ripple/protocol/SystemParameters.h>
 #include <ripple/protocol/UintTypes.h>
 #include <ripple/rpc/ServerHandler.h>
+#include <ripple/rpc/impl/RPCHelpers.h>
 #include <ripple/beast/core/LexicalCast.h>
 
 #include <boost/algorithm/string/predicate.hpp>
@@ -1360,6 +1361,20 @@ rpcCmdLineToJson (std::vector<std::string> const& args,
 
     jvRequest   = rpParser.parseCommand (args[0], jvRpcParams, true);
 
+    auto insert_api_version = [](Json::Value & jr){
+        if( jr.isObject() &&
+            !jr.isMember(jss::error) &&
+            !jr.isMember(jss::api_version))
+        {
+            jr[jss::api_version] = RPC::ApiMaximumSupportedVersion;
+        }
+    };
+
+    if(jvRequest.isObject())
+        insert_api_version(jvRequest);
+    else if(jvRequest.isArray())
+        std::for_each(jvRequest.begin(), jvRequest.end(), insert_api_version);
+
     JLOG (j.trace()) << "RPC Request: " << jvRequest << std::endl;
     return jvRequest;
 }

src/ripple/protocol/jss.h

@@ -123,6 +123,8 @@ JSS ( alternatives );               // out: PathRequest, RipplePathFind
 JSS ( amendment_blocked );          // out: NetworkOPs
 JSS ( amendments );                 // in: AccountObjects, out: NetworkOPs
 JSS ( amount );                     // out: AccountChannels
+JSS ( api_version);                 // in: many, out: Version
+JSS ( api_version_low);             // out: Version
 JSS ( applied );                    // out: SubmitTransaction
 JSS ( asks );                       // out: Subscribe
 JSS ( assets );                     // out: GatewayBalances
@@ -265,6 +267,8 @@ JSS ( index );                      // in: LedgerEntry, DownloadShard
                                     // field
 JSS ( info );                       // out: ServerInfo, ConsensusInfo, FetchInfo
 JSS ( internal_command );           // in: Internal
+JSS ( invalid_API_version );        // out: Many, when a request has an invalid
+                                    //      version
 JSS ( io_latency_ms );              // out: NetworkOPs
 JSS ( ip );                         // in: Connect, out: OverlayImpl
 JSS ( issuer );                     // in: RipplePathFind, Subscribe,

src/ripple/rpc/Context.h

@@ -55,6 +55,7 @@ struct Context
     LedgerMaster& ledgerMaster;
     Resource::Consumer& consumer;
     Role role;
+    unsigned int apiVersion;
     std::shared_ptr<JobQueue::Coro> coro {};
     InfoSub::pointer infoSub {};
     Headers headers {};

src/ripple/rpc/RPCHandler.h

@@ -33,7 +33,7 @@ struct Context;
 /** Execute an RPC command and store the results in a Json::Value. */
 Status doCommand (RPC::Context&, Json::Value&);
 
-Role roleRequired (std::string const& method );
+Role roleRequired (unsigned int version, std::string const& method );
 
 } // RPC
 } // ripple

src/ripple/rpc/impl/Handler.cpp

@@ -20,6 +20,7 @@
 #include <ripple/rpc/impl/Handler.h>
 #include <ripple/rpc/handlers/Handlers.h>
 #include <ripple/rpc/handlers/Version.h>
+#include <ripple/rpc/impl/RPCHelpers.h>
 
 namespace ripple {
 namespace RPC {
@@ -129,16 +130,21 @@ class HandlerTable {
     explicit
     HandlerTable (const Handler(&entries)[N])
     {
-        for (std::size_t i = 0; i < N; ++i)
+        for(auto v = RPC::ApiMinimumSupportedVersion; v <= RPC::ApiMaximumSupportedVersion; ++v)
         {
-            auto const& entry = entries[i];
-            assert (table_.find(entry.name_) == table_.end());
-            table_[entry.name_] = entry;
+            for (std::size_t i = 0; i < N; ++i)
+            {
+                auto & innerTable = table_[versionToIndex(v)];
+                auto const& entry = entries[i];
+                assert (innerTable.find(entry.name_) == innerTable.end());
+                innerTable[entry.name_] = entry;
+            }
+
+            // This is where the new-style handlers are added.
+            // This is also where different versions of handlers are added.
+            addHandler<LedgerHandler>(v);
+            addHandler<VersionHandler>(v);
         }
-
-        // This is where the new-style handlers are added.
-        addHandler<LedgerHandler>();
-        addHandler<VersionHandler>();
     }
 
   public:
@@ -148,45 +154,59 @@ class HandlerTable {
         return handlerTable;
     }
 
-    Handler const* getHandler(std::string name) const
+    Handler const* getHandler(unsigned version, std::string name) const
     {
-        auto i = table_.find(name);
-        return i == table_.end() ? nullptr : &i->second;
+        if(version > RPC::ApiMaximumSupportedVersion || version < RPC::ApiMinimumSupportedVersion)
+            return nullptr;
+        auto & innerTable = table_[versionToIndex(version)];
+        auto i = innerTable.find(name);
+        return i == innerTable.end() ? nullptr : &i->second;
     }
 
     std::vector<char const*>
     getHandlerNames() const
     {
-        std::vector<char const*> ret;
-        ret.reserve(table_.size());
-        for (auto const& i : table_)
-            ret.push_back(i.second.name_);
-        return ret;
+        std::unordered_set<char const*> name_set;
+        for ( int index = 0; index < table_.size(); ++index)
+        {
+            for(auto const& h : table_[index])
+            {
+                name_set.insert(h.second.name_);
+            }
+        }
+        return std::vector<char const*>(name_set.begin(), name_set.end());
     }
 
   private:
-    std::map<std::string, Handler> table_;
+    std::array<std::map<std::string, Handler>, APINumberVersionSupported> table_;
 
     template <class HandlerImpl>
-    void addHandler()
+    void addHandler(unsigned version)
     {
-        assert (table_.find(HandlerImpl::name()) == table_.end());
+        assert (version >= RPC::ApiMinimumSupportedVersion && version <= RPC::ApiMaximumSupportedVersion);
+        auto & innerTable = table_[versionToIndex(version)];
+        assert (innerTable.find(HandlerImpl::name()) == innerTable.end());
 
         Handler h;
         h.name_ = HandlerImpl::name();
         h.valueMethod_ = &handle<Json::Value, HandlerImpl>;
         h.role_ = HandlerImpl::role();
         h.condition_ = HandlerImpl::condition();
 
-        table_[HandlerImpl::name()] = h;
+        innerTable[HandlerImpl::name()] = h;
+    }
+
+    inline unsigned versionToIndex(unsigned version) const
+    {
+        return version - RPC::ApiMinimumSupportedVersion;
     }
 };
 
 } // namespace
 
-Handler const* getHandler(std::string const& name)
+Handler const* getHandler(unsigned version, std::string const& name)
 {
-    return HandlerTable::instance().getHandler(name);
+    return HandlerTable::instance().getHandler(version, name);
 }
 
 std::vector<char const*>

src/ripple/rpc/impl/Handler.h

@@ -51,7 +51,7 @@ struct Handler
     RPC::Condition condition_;
 };
 
-Handler const* getHandler (std::string const&);
+Handler const* getHandler (unsigned int version, std::string const&);
 
 /** Return a Json::objectValue with a single entry. */
 template <class Value>

src/ripple/rpc/impl/RPCHandler.cpp

@@ -141,7 +141,7 @@ error_code_i fillHandler (Context& context,
 
     JLOG (context.j.trace()) << "COMMAND:" << strCommand;
     JLOG (context.j.trace()) << "REQUEST:" << context.params;
-    auto handler = getHandler(strCommand);
+    auto handler = getHandler(context.apiVersion, strCommand);
 
     if (!handler)
         return rpcUNKNOWN_COMMAND;
@@ -296,9 +296,9 @@ Status doCommand (
     return rpcUNKNOWN_COMMAND;
 }
 
-Role roleRequired (std::string const& method)
+Role roleRequired (unsigned int version, std::string const& method)
 {
-    auto handler = RPC::getHandler(method);
+    auto handler = RPC::getHandler(version, method);
 
     if (!handler)
         return Role::FORBID;

src/ripple/rpc/impl/RPCHelpers.cpp

@@ -716,5 +716,24 @@ beast::SemanticVersion const firstVersion("1.0.0");
 beast::SemanticVersion const goodVersion("1.0.0");
 beast::SemanticVersion const lastVersion("1.0.0");
 
+unsigned int getAPIVersionNumber(Json::Value const& jv)
+{
+    static Json::Value const minVersion (RPC::ApiMinimumSupportedVersion);
+    static Json::Value const maxVersion (RPC::ApiMaximumSupportedVersion);
+    static Json::Value const invalidVersion (RPC::APIInvalidVersion);
+
+    Json::Value requestedVersion(RPC::APIVersionIfUnspecified);
+    if(jv.isObject())
+    {
+        requestedVersion = jv.get (jss::api_version, requestedVersion);
+    }
+    if( !(requestedVersion.isInt() || requestedVersion.isUInt()) ||
+        requestedVersion < minVersion || requestedVersion > maxVersion)
+    {
+        requestedVersion = invalidVersion;
+    }
+    return requestedVersion.asUInt();
+}
+
 } // RPC
 } // ripple

src/ripple/rpc/impl/RPCHelpers.h

@@ -114,10 +114,42 @@ parseRippleLibSeed(Json::Value const& params);
 std::pair<PublicKey, SecretKey>
 keypairForSignature(Json::Value const& params, Json::Value& error);
 
+/**
+ * API version numbers used in API version 1
+ */
 extern beast::SemanticVersion const firstVersion;
 extern beast::SemanticVersion const goodVersion;
 extern beast::SemanticVersion const lastVersion;
 
+/**
+ * API version numbers used in later API versions
+ *
+ * Requests with a version number in the range
+ * [ApiMinimumSupportedVersion, ApiMaximumSupportedVersion]
+ * are supported.
+ *
+ * Network Requests without explicit version numbers use
+ * APIVersionIfUnspecified. APIVersionIfUnspecified is 1,
+ * because all the RPC requests with a version >= 2 must
+ * explicitly specify the version in the requests.
+ * Note that APIVersionIfUnspecified will be lower than
+ * ApiMinimumSupportedVersion when we stop supporting API
+ * version 1.
+ *
+ * Command line Requests use ApiMaximumSupportedVersion.
+ */
+
+constexpr unsigned int APIInvalidVersion = 0;
+constexpr unsigned int APIVersionIfUnspecified = 1;
+constexpr unsigned int ApiMinimumSupportedVersion = 1;
+constexpr unsigned int ApiMaximumSupportedVersion = 1;
+constexpr unsigned int APINumberVersionSupported = ApiMaximumSupportedVersion -
+                                                   ApiMinimumSupportedVersion + 1;
+
+static_assert (ApiMinimumSupportedVersion >= APIVersionIfUnspecified);
+static_assert (ApiMaximumSupportedVersion >= ApiMinimumSupportedVersion);
+
+
 template <class Object>
 void
 setVersion(Object& parent)
@@ -131,6 +163,20 @@ setVersion(Object& parent)
 std::pair<RPC::Status, LedgerEntryType>
     chooseLedgerEntryType(Json::Value const& params);
 
+/**
+ * Retrieve the api version number from the json value
+ *
+ * Note that APIInvalidVersion will be returned if
+ * 1) the version number field has a wrong format
+ * 2) the version number retrieved is out of the supported range
+ * 3) the version number is unspecified and
+ *    APIVersionIfUnspecified is out of the supported range
+ *
+ * @param value a Json value that may or may not specifies
+ *        the api version number
+ * @return the api version number
+ */
+unsigned int getAPIVersionNumber(const Json::Value & value);
 } // RPC
 } // ripple