Universal JSON API library. More...

#include <assert.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <unistd.h>
#include "japi.h"
#include "creadline.h"
#include "japi_intern.h"
#include "japi_pushsrv.h"
#include "japi_pushsrv_intern.h"
#include "japi_utils.h"
#include "networking.h"
#include "prntdbg.h"
#include "rw_n.h"

Include dependency graph for japi.c:

Functions
int	japi_process_message (japi_context ctx, const char request, char **response, int socket)
	Process the JSON request. More...

int	japi_shutdown (japi_context *ctx)
	Shutdown the JAPI server. More...

int	japi_destroy (japi_context *ctx)
	Destroy a JAPI context. More...

int	japi_register_request (japi_context ctx, const char req_name, japi_req_handler req_handler)
	Register a JAPI request handler. More...

japi_context *	japi_init (void *userptr)
	Create and initialize a new JAPI context. More...

int	japi_set_max_allowed_clients (japi_context *ctx, uint16_t num)
	Set the number of allowed clients. More...

int	japi_include_args_in_response (japi_context *ctx, bool include_args)
	Configure context to include request arguments in response. More...

int	japi_add_client (japi_context *ctx, int socket)
	Add client. More...

int	japi_remove_client (japi_context *ctx, int socket)
	Remove client. More...

int	japi_remove_all_clients (japi_context *ctx)
	Remove all clients. More...

int	japi_start_server (japi_context ctx, const char port)
	Start a JAPI server. More...

void	japi_cmd_list (japi_context ctx, json_object request, json_object *response)
	Provide the names of all registered commands as a JAPI response. More...

void	japi_request_not_found_handler (japi_context ctx, json_object request, json_object *response)
	Default handler for reacting to unknown requests. More...

Detailed Description

Universal JSON API library.

Author: Christopher Stender

Date: 2018-02-15

Version: 0.1

libjapi is a universal JSON API library.

Copyright: Copyright (c) 2023 Fraunhofer IIS

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Function Documentation

int japi_add_client	(	japi_context *	ctx,
		int	socket
	)

Add client.

Add client to JAPI context client list.

Parameters

ctx	JAPI context
socket	The socket to be added

Returns: On success, 0 is returned. On error, -1 if memory allocation failed, is returned.

References japi_context::clients, japi_client::crl_buffer, japi_context::lock, creadline_buf_t::nbytes, japi_client::next, japi_context::num_clients, and japi_client::socket.

Referenced by japi_start_server().

void japi_cmd_list	(	japi_context *	ctx,
		json_object *	request,
		json_object *	response
	)

Provide the names of all registered commands as a JAPI response.

Provides the names of all registered commands as a JAPI response.

Parameters

ctx	JAPI context
request	Pointer to JAPI JSON request
response	Pointer to JAPI JSON response

Note: Parameter 'request' declared, although not used in function. Function declaration needs to be identical to respective handler.

References japi_request::name, japi_request::next, and japi_context::requests.

Referenced by japi_init().

int japi_destroy ( japi_context * ctx )

Destroy a JAPI context.

Destroy the JAPI context pointed to by ctx and release allocated memory.

Parameters

ctx	JAPI context

Returns: On succes, zero is returned. On error, -1 is returned.

References japi_pushsrv_destroy(), japi_context::lock, japi_pushsrv_context::next, japi_request::next, japi_context::push_services, and japi_context::requests.

int japi_include_args_in_response	(	japi_context *	ctx,
		bool	include_args
	)

Configure context to include request arguments in response.

Configure context to include request arguments in response

Parameters

ctx	JAPI context
include_args	Include request arguments in response.

Returns: On success, zero is returned. On error, -1 for empty JAPI context, is returned.

References japi_context::include_args_in_response.

japi_context* japi_init ( void * userptr )

Create and initialize a new JAPI context.

Create, initialize and return a new japi_context object.

Parameters

userptr Pointer to user data or NULL. If a valid pointer is provided a request handler can access that data later.

Returns: On success, a japi_context object is returned. On error, NULL is returned.

References japi_context::clients, japi_context::include_args_in_response, japi_context::init, japi_cmd_list(), japi_pushsrv_list(), japi_pushsrv_subscribe(), japi_pushsrv_unsubscribe(), japi_register_request(), japi_request_not_found_handler(), japi_context::lock, japi_context::max_clients, japi_context::num_clients, japi_context::push_services, japi_context::requests, japi_context::shutdown, and japi_context::userptr.

int japi_process_message	(	japi_context *	ctx,
		const char *	request,
		char **	response,
		int	socket
	)

Process the JSON request.

Steps performed while processing a JSON request:

Convert the received message into a JSON object
Extract the request name
Search a suitable request handler
Call the request handler
Prepare the JSON response
Free memory

Parameters

ctx	Japi context
request	Request to process
response	From request build response
socket	Network socket

Returns: On success, 0 returned. On error, -1 is returned.

References japi_context::include_args_in_response, japi_get_jobj_as_ndstr(), and japi_get_value_as_str().

Referenced by japi_start_server().

int japi_register_request	(	japi_context *	ctx,
		const char *	req_name,
		japi_req_handler	req_handler
	)

Register a JAPI request handler.

Register a JAPI request handler provided as a function pointer req_handler for the request specified by req_name.

Parameters

ctx	JAPI context
req_name	Request name
req_handler	Function pointer

Returns: On success, zero is returned. On error, -1 for empty JAPI context, -2 for empty request name, -3 for empty request handler, -4 for duplicate naming, -5 for failed memory allocation, -6 for bad request name (starting with "japi_") is returned.

References japi_request::func, japi_context::init, japi_request::name, japi_request::next, and japi_context::requests.

Referenced by japi_init().

int japi_remove_all_clients ( japi_context * ctx )

Remove all clients.

Remove all clients from JAPI context and pushs service context.

Parameters

ctx	JAPI context

Returns: On success, 0 is returned. On error, -1 is returned if a client cannot be removed.

References japi_context::clients, japi_remove_client(), japi_client::next, and japi_client::socket.

Referenced by japi_start_server().

int japi_remove_client	(	japi_context *	ctx,
		int	socket
	)

Remove client.

Remove client from JAPI context and pushs service context.

Parameters

ctx	JAPI context
socket	The socket to be removed

Returns: On success, 0 is returned. On error, -1 if client is not removed, is returned.

References japi_context::clients, japi_pushsrv_remove_client_from_all_pushsrv(), japi_context::lock, japi_client::next, japi_context::num_clients, and japi_client::socket.

Referenced by japi_remove_all_clients(), and japi_start_server().

void japi_request_not_found_handler	(	japi_context *	ctx,
		json_object *	request,
		json_object *	response
	)

Default handler for reacting to unknown requests.

Can be overwritten by the user by registering a command called request_not_found_handler. Is called if no suitable registered request is found for the received command. Adds a field named "error" to the response which contains a string describing the issue.

Parameters

ctx	JAPI context
request	Pointer to JAPI JSON request
response	Pointer to JAPI JSON response

Note: Parameter 'ctx' and request' declared, although not used in function. Function declaration needs to be identical to respective handler.

Referenced by japi_init().

int japi_set_max_allowed_clients	(	japi_context *	ctx,
		uint16_t	num
	)

Set the number of allowed clients.

Set the maximal number of allowed clients.

Parameters

ctx	JAPI context
num	Number of clients to be allowed. 0 stands for unlimited.

Returns: On success, zero is returned. On error, -1 for empty JAPI context, is returned.

References japi_context::max_clients.

int japi_shutdown ( japi_context * ctx )

Shutdown the JAPI server.

Parameters

ctx	JAPI context

Returns: On success, zero is returned. On error, -1 for empty JAPI context, is returned.

References japi_context::shutdown.

int japi_start_server	(	japi_context *	ctx,
		const char *	port
	)

Start a JAPI server.

Start a JAPI server on the given port.

Parameters

ctx	JAPI context
port	Port to be used by the JAPI server

Returns: Only returns in case of an error.

References japi_context::clients, creadline_r(), japi_add_client(), japi_process_message(), japi_remove_all_clients(), japi_remove_client(), japi_context::max_clients, japi_context::num_clients, japi_context::shutdown, tcp_start_server(), and write_n().

Functions

Detailed Description

Function Documentation