wwa::json_rpc Namespace Reference

Library namespace. More...

Namespaces
namespace	details
	Contains the implementation details of the JSON RPC library.

Classes
class	dispatcher
	A class that manages JSON RPC method handlers and processes JSON RPC requests. More...
class	dispatcher_private
	Private implementation of the JSON RPC dispatcher class. More...
class	exception
	JSON RPC Exception class. More...
struct	jsonrpc_request
	Represents a JSON RPC request. More...
class	method_not_found_exception
	Exception thrown when the method is not found. More...

Functions
static void	from_json (const nlohmann::json &j, jsonrpc_request &r)
	Deserializes a JSON object into a jsonrpc_request structure.
WWA_JSONRPC_EXPORT nlohmann::json	generate_error_response (const exception &e, const nlohmann::json &id=nlohmann::json::value_t::null)
	Generates an error response.
WWA_JSONRPC_EXPORT int	get_error_code (const nlohmann::json &response)
	Gets the error code from an error response.
WWA_JSONRPC_EXPORT std::string	get_error_message (const nlohmann::json &response)
	Gets the error message from an error response.
WWA_JSONRPC_EXPORT nlohmann::json	get_request_id (const nlohmann::json &request)
	Get the request id object.
WWA_JSONRPC_EXPORT bool	is_error_response (const nlohmann::json &response)
	Checks whether response is an error response.
WWA_JSONRPC_EXPORT bool	is_valid_request_id (const nlohmann::json &id)
	Checks if the provided JSON value is a valid JSON RPC request ID.
WWA_JSONRPC_EXPORT std::string	serialize_repsonse (const nlohmann::json &response)
	Serializes the JSON RPC response to a string.

Variables
static constexpr std::string_view	err_bad_id_type = "ID must be either a number, a string, or null"
	Error message for when the ID is not a number, a string, or null.
static constexpr std::string_view	err_bad_params_type = "Parameters must be either an array or an object or omitted"
	Error message for when the parameters are not an array or an object.
static constexpr std::string_view	err_bad_request = "Bad request"
	Error request for when the request is not valid.
static constexpr std::string_view	err_empty_batch = "Empty batch request"
	Error message for when the batch request is empty.
static constexpr std::string_view	err_empty_method = "Method cannot be empty"
	Error message for when the method is empty.
static constexpr std::string_view	err_invalid_params_passed_to_method = "Invalid parameters passed to method"
	Error message for when the parameters passed to the method are not correct.
static constexpr std::string_view	err_method_not_found = "Method not found"
	Error message for when the method is not found.
static constexpr std::string_view	err_not_jsonrpc_2_0_request = "Not a JSON-RPC 2.0 request"
	Error message for when the request is not a JSON-RPC 2.0 request.

Detailed Description

Library namespace.

Function Documentation

from_json()

static void wwa::json_rpc::from_json ( const nlohmann::json & j, jsonrpc_request & r )

static

Deserializes a JSON object into a jsonrpc_request structure.

Parameters

j	The JSON object to deserialize.
r	The jsonrpc_request structure to populate.

This function deserializes a JSON object into a jsonrpc_request structure.

• It extracts the jsonrpc version, method name, params, and id from the JSON object.
• If the params field is not present, it defaults to an empty array.
• If the params field is an object, it is wrapped in an array.

Note

This function cannot be moved to an anonymous namespace because of Argument-Dependent Lookup (ADL).

See also

https://www.jsonrpc.org/specification#request_object

https://github.com/nlohmann/json?tab=readme-ov-file#arbitrary-types-conversions

Definition at line 38 of file request.cpp.

{
    r.params = nlohmann::json(nlohmann::json::value_t::discarded);
    r.id     = nlohmann::json(nlohmann::json::value_t::discarded);
 
    j.at("jsonrpc").get_to(r.jsonrpc);
    j.at("method").get_to(r.method);
 
    if (j.contains("params")) {
        r.params = j["params"];
    }
 
    if (j.contains("id")) {
        r.id = j["id"];
    }
 
    if (r.params.is_discarded()) {
        r.params = nlohmann::json::array();
    }
    else if (r.params.is_object()) {
        r.params = nlohmann::json::array({r.params});
    }
}

generate_error_response()

nlohmann::json wwa::json_rpc::generate_error_response	(	const exception &	e,
		const nlohmann::json &	id = nlohmann::json::value_t::null )

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 43 of file utils.cpp.

{
    // clang-format off
    return {
        {"jsonrpc", "2.0"},
        {"error", e.to_json()},
        {"id", id}
    };
    // clang-format on
}

get_error_code()

int wwa::json_rpc::get_error_code

(

const nlohmann::json &

response

)

Gets the error code from an error response.

Parameters

response

JSON RPC error response.

Returns

The error code.

Definition at line 33 of file utils.cpp.

{
    return response.at("error").value("code", 0);
}

get_error_message()

std::string wwa::json_rpc::get_error_message

(

const nlohmann::json &

response

)

Gets the error message from an error response.

Parameters

response

JSON RPC error response.

Returns

The error message.

Definition at line 38 of file utils.cpp.

{
    return response.at("error").value("message", "");
}

get_request_id()

nlohmann::json wwa::json_rpc::get_request_id

(

const nlohmann::json &

request

)

Get the request id object.

Parameters

request

JSON RPC request

Returns

Request ID

This function extracts the ID field from a JSON RPC request object. If the id field is not present or is not valid (see is_valid_request_id()), it returns a null JSON value.

Definition at line 17 of file utils.cpp.

{
    auto id = request.contains("id") ? request["id"] : nlohmann::json(nullptr);
    return is_valid_request_id(id) ? id : nlohmann::json(nullptr);
}

is_error_response()

bool wwa::json_rpc::is_error_response

(

const nlohmann::json &

response

)

Checks whether response is an error response.

Parameters

response

JSON RPC response.

Returns

Whether the response is an error response.

Definition at line 28 of file utils.cpp.

{
    return response.is_object() && response.contains("error") && response["error"].is_object();
}

is_valid_request_id()

bool wwa::json_rpc::is_valid_request_id

(

const nlohmann::json &

id

)

Checks if the provided JSON value is a valid JSON RPC request ID.

Parameters

id	The JSON value to check.

Returns

true if the JSON value is a valid request ID, false otherwise.

This function checks if the provided JSON value is a valid JSON RPC request ID. According to the JSON RPC specification, a valid request ID can be a string, a number, or null. Additionally, this function also considers a discarded JSON value as valid.

See also

https://www.jsonrpc.org/specification#request_object

Definition at line 12 of file utils.cpp.

{
    return id.is_string() || id.is_number() || id.is_null() || id.is_discarded();
}

serialize_repsonse()

std::string wwa::json_rpc::serialize_repsonse

(

const nlohmann::json &

response

)

Serializes the JSON RPC response to a string.

Parameters

response

Response to serialize.

Returns

Response serialized to a string' empty string if response.is_discarded() is true.

Definition at line 23 of file utils.cpp.

{
    return response.is_discarded() ? std::string{} : response.dump();
}