wwa::json_rpc::dispatcher_private Class Reference

Private implementation of the JSON RPC dispatcher class. More...

#include <dispatcher_p.h>

Collaboration diagram for wwa::json_rpc::dispatcher_private:

Public Member Functions
	dispatcher_private (dispatcher *q)
	Constructs a new dispatcher_private object.
void	add_handler (std::string &&method, dispatcher::handler_t &&handler)
	Adds a method handler.
nlohmann::json	process_request (const nlohmann::json &request, const nlohmann::json &extra)
	Processes a JSON RPC request.

Static Public Member Functions
static nlohmann::json	generate_error_response (const exception &e, const nlohmann::json &id)
	Generates an error response.

Private Member Functions
nlohmann::json	invoke (const std::string &method, const nlohmann::json &params, const nlohmann::json &extra)
	Invokes a method handler.
nlohmann::json	process_batch_request (const nlohmann::json &request, const nlohmann::json &extra)
	Processes a batch request.

Static Private Member Functions
static jsonrpc_request	parse_request (const nlohmann::json &request, nlohmann::json &extra)
	Parses a JSON RPC request.
static void	validate_request (const jsonrpc_request &r)
	Validates a JSON RPC request.

Private Attributes
std::unordered_map< std::string, dispatcher::handler_t, hasher, std::equal_to<> >	m_methods
	Map of method names to handler functions.
dispatcher *	q_ptr
	Pointer to the public dispatcher object.

Detailed Description

Private implementation of the JSON RPC dispatcher class.

This class contains the private members and methods used by the dispatcher class to manage method handlers and process requests.

Definition at line 63 of file dispatcher_p.h.

Constructor & Destructor Documentation

dispatcher_private()

wwa::json_rpc::dispatcher_private::dispatcher_private ( dispatcher * q )

inlineexplicit

Constructs a new dispatcher_private object.

Parameters

q	Pointer to the public dispatcher object.

Definition at line 70 of file dispatcher_p.h.

: q_ptr(q) {}

Member Function Documentation

add_handler()

void wwa::json_rpc::dispatcher_private::add_handler	(	std::string &&	method,
		dispatcher::handler_t &&	handler )

Adds a method handler.

Parameters

method	The name of the method.
handler	The handler function.

This method registers a handler function for a given method name. The handler function will be invoked when a request for the specified method is received.

Definition at line 80 of file dispatcher_p.cpp.

{
    this->m_methods.try_emplace(std::move(method), std::move(handler));
}

generate_error_response()

nlohmann::json wwa::json_rpc::dispatcher_private::generate_error_response ( const exception & e, const nlohmann::json & id )

static

Generates an error response.

Parameters

e	The exception containing the error details.
id	The ID of the request.

Returns

The error response serialized into a JSON object.

This method creates a JSON RPC error response based on the provided exception and request ID.

See also

exception::to_json()

Definition at line 198 of file dispatcher_p.cpp.

{
    return nlohmann::json({{"jsonrpc", "2.0"}, {"error", e.to_json()}, {"id", id}});
}

invoke()

nlohmann::json wwa::json_rpc::dispatcher_private::invoke ( const std::string & method, const nlohmann::json & params, const nlohmann::json & extra )

private

Invokes a method handler.

Parameters

method	The name of the method to invoke.
params	The parameters for the method.
extra	The extra parameter to pass to the method handlers.

Returns

The result of the method invocation serialized into a JSON object.

This method finds the handler for the specified method and invokes it with the provided parameters.

Exceptions

exception

If the method is not found or the invocation fails.

See also

exception::METHOD_NOT_FOUND

Definition at line 204 of file dispatcher_p.cpp.

{
    if (const auto it = this->m_methods.find(method); it != this->m_methods.end()) {
        this->q_ptr->on_method(method, extra);
        const auto response = it->second(extra, params);
        this->q_ptr->on_request_processed(method, 0, extra);
        return response;
    }
 
    throw exception(exception::METHOD_NOT_FOUND, err_method_not_found);
}

parse_request()

jsonrpc_request wwa::json_rpc::dispatcher_private::parse_request ( const nlohmann::json & request, nlohmann::json & extra )

staticprivate

Parses a JSON RPC request.

Parameters

request	The JSON RPC request as a nlohmann::json object.
extra	Extra fields extracted from request

Returns

The parsed JSON RPC request.

This method extracts the components of a JSON RPC request from the provided JSON object.

Definition at line 85 of file dispatcher_p.cpp.

{
    try {
        auto req = request.get<jsonrpc_request>();
        extra    = request;
        extra.erase("jsonrpc");
        extra.erase("method");
        extra.erase("params");
        extra.erase("id");
        return req;
    }
    catch (const nlohmann::json::exception& e) {
        throw exception(exception::INVALID_REQUEST, e.what());
    }
}

process_batch_request()

nlohmann::json wwa::json_rpc::dispatcher_private::process_batch_request ( const nlohmann::json & request, const nlohmann::json & extra )

private

Processes a batch request.

Parameters

request	The batch request as a nlohmann::json array.
extra	The extra parameter to pass to the method handlers.

Returns

The response serialized into a JSON array.

This method processes a batch request by invoking the method handlers for each request in the batch.

See also

dispatcher::process_request()

Definition at line 102 of file dispatcher_p.cpp.

{
    if (request.empty()) {
        this->q_ptr->on_request(extra);
        this->q_ptr->on_request_processed({}, exception::INVALID_REQUEST, extra);
        return dispatcher_private::generate_error_response(
            exception(exception::INVALID_REQUEST, err_empty_batch), nlohmann::json(nullptr)
        );
    }
 
    auto response = nlohmann::json::array();
    for (const auto& req : request) {
        if (!req.is_object()) {
            this->q_ptr->on_request(extra);
            const auto r = dispatcher_private::generate_error_response(
                exception(exception::INVALID_REQUEST, err_not_jsonrpc_2_0_request), nlohmann::json(nullptr)
            );
 
            response.push_back(r);
            this->q_ptr->on_request_processed({}, exception::INVALID_REQUEST, extra);
        }
        else if (const auto res = this->process_request(req, extra); !res.is_discarded()) {
            response.push_back(res);
        }
    }
 
    return response.empty() ? nlohmann::json(nlohmann::json::value_t::discarded) : response;
}

process_request()

nlohmann::json wwa::json_rpc::dispatcher_private::process_request	(	const nlohmann::json &	request,
		const nlohmann::json &	extra )

Processes a JSON RPC request.

Parameters

request	The JSON RPC request as a nlohmann::json object.
extra	The extra parameter to pass to the method handlers.

Returns

The response serialized into a JSON object.

This method parses the JSON RPC request, validates it, and invokes the appropriate method handler.

See also

dispatcher::process_request()

Definition at line 132 of file dispatcher_p.cpp.

{
    if (request.is_array()) {
        return this->process_batch_request(request, extra);
    }
 
    this->q_ptr->on_request(extra);
    auto request_id = request.contains("id") ? request["id"] : nlohmann::json(nullptr);
    if (!is_valid_request_id(request_id)) {
        request_id = nlohmann::json(nullptr);
    }
 
    std::string method;
    nlohmann::json extra_data = extra;
    try {
        nlohmann::json extra_fields;
        auto req = dispatcher_private::parse_request(request, extra_fields);
        dispatcher_private::validate_request(req);
        method     = req.method;
        request_id = req.id;
 
        if (extra.is_object() && !extra_fields.empty()) {
            extra_data["extra"] = extra_fields;
        }
 
        const auto res = this->invoke(method, req.params, extra_data);
        if (!req.id.is_discarded()) {
            return nlohmann::json({{"jsonrpc", "2.0"}, {"result", res}, {"id", req.id}});
        }
 
        // NOLINTNEXTLINE(modernize-return-braced-init-list) -- braced init will create a JSON array
        return nlohmann::json(nlohmann::json::value_t::discarded);
    }
    catch (const exception& e) {
        this->q_ptr->on_request_processed(method, e.code(), extra_data);
        return request_id.is_discarded() ? nlohmann::json(nlohmann::json::value_t::discarded)
                                         : dispatcher_private::generate_error_response(e, request_id);
    }
    catch (const std::exception& e) {
        this->q_ptr->on_request_processed(method, exception::INTERNAL_ERROR, extra_data);
        return request_id.is_discarded() ? nlohmann::json(nlohmann::json::value_t::discarded)
                                         : dispatcher_private::generate_error_response(
                                               exception(exception::INTERNAL_ERROR, e.what()), request_id
                                           );
    }
}

validate_request()

void wwa::json_rpc::dispatcher_private::validate_request ( const jsonrpc_request & r )

staticprivate

Validates a JSON RPC request.

Parameters

r	The JSON RPC request to validate.

This method checks the validity of the JSON RPC request, ensuring that all required fields are present and correctly formatted.

Exceptions

exception

If the request is invalid.

See also

exception::INVALID_REQUEST, exception::INVALID_PARAMS

Definition at line 179 of file dispatcher_p.cpp.

{
    if (r.jsonrpc != "2.0") {
        throw json_rpc::exception(json_rpc::exception::INVALID_REQUEST, json_rpc::err_not_jsonrpc_2_0_request);
    }
 
    if (!r.params.is_array()) {
        throw json_rpc::exception(json_rpc::exception::INVALID_PARAMS, json_rpc::err_bad_params_type);
    }
 
    if (r.method.empty()) {
        throw json_rpc::exception(json_rpc::exception::INVALID_REQUEST, json_rpc::err_empty_method);
    }
 
    if (!is_valid_request_id(r.id)) {
        throw json_rpc::exception(json_rpc::exception::INVALID_REQUEST, json_rpc::err_bad_id_type);
    }
}

Member Data Documentation

m_methods

std::unordered_map<std::string, dispatcher::handler_t, hasher, std::equal_to<> > wwa::json_rpc::dispatcher_private::m_methods

private

Map of method names to handler functions.

Definition at line 111 of file dispatcher_p.h.

q_ptr

dispatcher* wwa::json_rpc::dispatcher_private::q_ptr

private

Pointer to the public dispatcher object.

Definition at line 109 of file dispatcher_p.h.

---

The documentation for this class was generated from the following files:

• dispatcher_p.h
• dispatcher_p.cpp