/*
* JsonRpc-Cpp - JSON-RPC implementation.
* Copyright (C) 2008 Sebastien Vincent <sebastien.vincent@cppextrem.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* \file jsonrpc_handler.h
* \brief JSON-RPC processor engine.
* \author Sebastien Vincent
*/
#ifndef JSONRPC_HANDLER_H
#define JSONRPC_HANDLER_H
#include <string>
#include <list>
#include <json/json.h>
/**
* \namespace Json
* \brief JSON (JavaScript Object Notation).
*/
namespace Json
{
/**
* \namespace Json::Rpc
* \brief JSON-RPC (remote procedure call using JSON as encoding format).
*/
namespace Rpc
{
/**
* \enum ErrorCode
* \brief JSON-RPC error codes.
* \note Value from -32099 to -32000 are reserved for implementation-defined server-errors.
*/
enum ErrorCode
{
PARSING_ERROR = -32700, /**< Invalid JSON. An error occurred on the server while parsing the JSON text. */
INVALID_REQUEST = -32600, /**< The received JSON not a valid JSON-RPC Request. */
METHOD_NOT_FOUND = -32601, /**< The requested remote-procedure does not exist / is not available. */
INVALID_PARAMS = -32602, /**< Invalid method parameters. */
INTERNAL_ERROR = -32603, /**< Internal JSON-RPC error. */
};
/**
* \class CallbackMethod
* \brief Callback-style method.
*/
class CallbackMethod
{
public:
/**
* \brief Destructor.
*/
virtual ~CallbackMethod();
/**
* \brief Call the method.
* \param msg JSON-RPC request or notification
* \param response response produced (may be Json::Value::null)
* \return true if message has been correctly processed, false otherwise
* \note Have to be implemented by subclasses
*/
virtual bool Call(const Json::Value& msg, Json::Value& response) = 0;
/**
* \brief Get the name of the methods (optional).
* \return name of the method as std::string
* \note Have to be implemented by subclasses
*/
virtual std::string GetName() const = 0;
/**
* \brief Get the description of the methods (optional).
* \return description
*/
virtual Json::Value GetDescription() const = 0;
};
/**
* \brief Template class that represent the RPC method.
*/
template<class T> class RpcMethod : public CallbackMethod
{
public:
/**
* \brief the T method signature.
*/
typedef bool (T::*Method)(const Json::Value& msg, Json::Value& response);
/**
* \brief Constructor.
* \param obj Object
* \param method the class
* \param name symbolic name (i.e. system.describe)
* \param description method description (in JSON format)
*/
RpcMethod(T& obj, Method method, const std::string& name, const Json::Value description = Json::Value::null)
{
m_obj = &obj;
m_name = name;
m_method = method;
m_description = description;
}
/**
* \brief Call the method.
* \param msg JSON-RPC request or notification
* \param response response produced (may be Json::Value::null)
* \return true if message has been correctly processed, false otherwise
*/
virtual bool Call(const Json::Value& msg, Json::Value& response)
{
(m_obj->*m_method)(msg, response);
}
/**
* \brief Get the name of the methods (optional).
* \return name of the method as std::string
* \note Have to be implemented by subclasses
*/
virtual std::string GetName() const
{
return m_name;
}
/**
* \brief Get the description of the methods (optional).
* \return description
*/
virtual Json::Value GetDescription() const
{
return m_description;
}
private:
/**
* \brief Object pointer.
*/
T* m_obj;
/**
* \brief Method of T class.
*/
Method m_method;
/**
* \brief Symbolic name.
*/
std::string m_name;
/**
* \brief JSON-formated description of the RPC method.
*/
Json::Value m_description;
};
/**
* \class Handler
* \brief Container of methods which can be called remotly.
*/
class Handler
{
public:
/**
* \brief Constructor.
*/
Handler();
/**
* \brief Copy constructor.
* \param handler Handler object to copy
*/
Handler(const Handler& handler);
/**
* \brief Destructor.
*/
~Handler();
/**
* \brief Add a new RPC method.
* \param method the method
*/
void AddMethod(CallbackMethod* method);
/**
* \brief Remote a RPC method.
* \param name name of the RPC method
*/
void DeleteMethod(const std::string& name);
/**
* \brief Process a JSON-RPC message.
* \param msg JSON-RPC message as std::string
* \param response JSON-RPC response (could be Json::Value::null)
* \return true if the request has been correctly processed, false otherwise (may be
* caused by parsed error, ...)
* \note in case msg is a notification, response is equal to Json::Value::null
* and the return value is true.
*/
bool Process(const std::string& msg, Json::Value& response);
/**
* \brief Process a JSON-RPC message.
* \param msg JSON-RPC message as C-String
* \param response JSON-RPC response (could be Json::Value::null)
* \return true if the request has been correctly processed, false otherwise (may be
* caused by parsed error, ...)
* \note in case msg is a notification, response is equal to Json::Value::null
* and the return value is true.
*/
bool Process(const char* msg, Json::Value& response);
/**
* \brief RPC method that get all the RPC methods and their description.
* \param msg request
* \param response response
* \return true if processed correctly, false otherwise
*/
bool SystemDescribe(const Json::Value& msg, Json::Value& response);
/**
* \brief Get a std::string representation of Json::Value.
* \param value JSON message
* \return string representation
*/
std::string GetString(Json::Value value);
private:
/**
* \brief JSON reader.
*/
Json::Reader m_reader;
/**
* \brief JSON write.
*/
Json::FastWriter m_writer;
/**
* \brief List of RPC methods.
*/
std::list<CallbackMethod*> m_methods;
/**
* \brief Find CallbackMethod by name.
* \param name name of the CallbackMethod
* \return a CallbackMethod pointer if found, 0 otherwise
*/
CallbackMethod* Lookup(const std::string& name) const;
/**
* \brief Check if the message is a valid JSON one.
* \param msg the message to check
* \param root message parsed (only valid if method returns true)
* \return true if the message is a JSON one, false otherwise
*/
bool Check(const std::string& msg, Json::Value& root);
};
} /* namespace Rpc */
} /* namespace Json */
#endif /* JSONRPC_HANDLER_H */
