https post

---

---

요즘 c언어가 별로 없다 보니 생각보다 자료나 연동에 있어서 고생을 많이 한다...

이번에 프로젝트에서 아두이노 라즈베리파이 plc.. 등등 연동하다가 https 웹소켓을 함께 연동하는 일이 생겨서

겸사겸사 올려본다.

/*==============================================================================================/
 *
 *  Copyright (C) 2021 Qsentech Software Corp Reaserch Institute
 *  All rights reserved.
 *
 *  Author : Lee Kyu Nam (nasanx2001@naver.com)
 *
 *==============================================================================================*/
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <curl/curl.h>
#include <time.h>
#include <unistd.h>
#include <sys/shm.h>

#include "cJSON.h"


#undef FALSE
#define FALSE 0
#undef TRUE
#define TRUE 1

#ifdef _WIN32
#undef snprintf
#define snprintf _snprintf
#endif

#define _status_item	28

typedef struct tm 	tm;

int old_min = 0;

struct _dev *dev_shm;
void *dev_shared_memory = (void *)0;
#define DEV_SHM_KEY		3131

struct _dev
{
	char polling_data[2000];
	int polling_flag;
	char ack_data[2000];
	int ack_flag;
};

struct _timer *timer_shm;
void *timer_shared_memory = (void *)0;
#define TIMER_SHM_KEY	2121

struct _timer
{
	int yyyy;
	int mm;
	int md;
	int hour;
	int min;
	int sec;
};

struct _set_Value *set_shm;
void *set_shared_memory = (void *)0;
#define SET_SHM_KEY	1111

struct _set_Value
{
	int sensor1;
    int sensor2;
    int sensor3;
    int sensor4;
    int sensor5;
};


/* Post JSON data to a server.
name and value must be UTF-8 strings.
Returns TRUE on success, FALSE on failure.
*/


// test용
//========================================================================
char *key_name[] = {"systemDate", "systemId", "sensor1", "sensor2", "sensor3", "sensor4", "sensor5"};


struct MemoryStruct
{
	char *memory;
	size_t size;
};

static size_t WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp)
{
	size_t realsize = size = nmemb;
	struct MemoryStruct *mem = (struct MemoryStruct *)userp;
	
	mem->memory = realloc(mem->memory, mem->size + realsize + 1);
	if(mem->memory == NULL)
	{
		printf("memory error\n");
		return 0;
	}
	
	memcpy(&(mem->memory[mem->size]), contents, realsize);
	mem->size += realsize;
	mem->memory[mem->size] = 0;
	
	return realsize;
}



int PostJSON(int item)
{
	int retcode = FALSE;
	cJSON *root = NULL;
	char *json = NULL;
	CURL *curl = NULL;
	CURLcode res = CURLE_FAILED_INIT;
	char errbuf[CURL_ERROR_SIZE] = { 0, };
	struct curl_slist *headers = NULL;
	char agent[1024] = { 0, };
	int i = 0;
	char timer[18];
	char *p;
	char buff[400];
	long statLong ;
	
	FILE *fp;
	fp = fopen("/home/ubuntu/log/post.txt", "a+");
	
	sprintf(timer, "%04d%02d%02d %02d:%02d:%02d", timer_shm->yyyy, timer_shm->mm, timer_shm->md, timer_shm->hour, timer_shm->min, timer_shm->sec);
	printf("%s\n", timer);

	root = cJSON_CreateObject();
	if(!root) {
		fprintf(fp, "[%04d-%02d-%02d %02d:%02d:%02d] Error: cJSON_CreateObject failed.\n", timer_shm->yyyy, timer_shm->mm, timer_shm->md, timer_shm->hour,timer_shm->min, timer_shm->sec);
		goto cleanup;
	}
	
	cJSON_AddStringToObject(root, key_name[i++], timer);
	
	memset(buff, 0x00, sizeof(buff));
	memcpy(buff, dev_shm->polling_data, strlen(dev_shm->polling_data));
	
	p = strtok(buff, ", ");
	while(p != NULL)
	{
		if(i < 7)
		{
			if((strcmp(p, "ex") != 0)) // ETX 테스트용
			{
				cJSON_AddStringToObject(root, key_name[i++], p);
			}
		}
		p = strtok(NULL, ", ");
	}
	
	json = cJSON_PrintUnformatted(root);
	if(!json) {
		fprintf(fp, "[%04d-%02d-%02d %02d:%02d:%02d] Error: cJSON_PrintUnformatted failed.\n", timer_shm->yyyy, timer_shm->mm, timer_shm->md, timer_shm->hour,timer_shm->min, timer_shm->sec);
		goto cleanup;
	}

	curl = curl_easy_init();
	if(!curl) {
		fprintf(fp, "[%04d-%02d-%02d %02d:%02d:%02d] Error: curl_easy_init failed.\n", timer_shm->yyyy, timer_shm->mm, timer_shm->md, timer_shm->hour,timer_shm->min, timer_shm->sec);
		goto cleanup;
	}
  
	// debug
	// printf("json = %s\n", json);

	curl_easy_setopt(curl, CURLOPT_CAINFO, "tset.crt");

	snprintf(agent, sizeof(agent), "libcurl/%s",
           curl_version_info(CURLVERSION_NOW)->version);
	agent[sizeof(agent) - 1] = 0;
	curl_easy_setopt(curl, CURLOPT_USERAGENT, agent);
	
	headers = curl_slist_append(headers, "Expect:");
	headers = curl_slist_append(headers, "Content-Type: application/json");
	curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
	
	curl_easy_setopt(curl, CURLOPT_POSTFIELDS, json);
	curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, -1L);
	
	
	
	/* This is a test server, it fakes a reply as if the json object were
		created */
	curl_easy_setopt(curl, CURLOPT_URL,
					"https://xxx-xxxxxx/xxx.com/xx/xxxxxx");
	
	
	curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, errbuf);
	curl_easy_setopt (curl, CURLOPT_FORBID_REUSE, 1L);
	
	res = curl_easy_perform(curl);
	if(res != CURLE_OK) {
		size_t len = strlen(errbuf);
		fprintf(fp, "\nlibcurl: (%d)\n ", res);
		if(len)
		fprintf(fp, "[%04d-%02d-%02d %02d:%02d:%02d]%s%s\n", timer_shm->yyyy, timer_shm->mm, timer_shm->md, timer_shm->hour,timer_shm->min, timer_shm->sec, errbuf, ((errbuf[len - 1] != '\n') ? "\n" : ""));
		fprintf(fp, "[%04d-%02d-%02d %02d:%02d:%02d]%s\n\n", timer_shm->yyyy, timer_shm->mm, timer_shm->md, timer_shm->hour,timer_shm->min, timer_shm->sec, curl_easy_strerror(res));
		//goto cleanup;
	}
	else{
		if( CURLE_OK == curl_easy_getinfo( curl , CURLINFO_HTTP_CODE , &statLong ) ){
			// printf("[%04d-%02d-%02d %02d:%02d:%02d] RCV_HTTP_CODE : %ld\n", timer_shm->yyyy, timer_shm->mm, timer_shm->md, timer_shm->hour,
			// timer_shm->min, timer_shm->sec, statLong);
			fprintf(fp, "[%04d-%02d-%02d %02d:%02d:%02d] RCV_HTTP_CODE : %ld\n", timer_shm->yyyy, timer_shm->mm, timer_shm->md, timer_shm->hour,timer_shm->min, timer_shm->sec, statLong);
			
			dev_shm->polling_flag = 0;
		}
	}
	
	retcode = TRUE;
	cleanup:
	fclose(fp);
	curl_slist_free_all(headers);
	curl_easy_cleanup(curl);
	cJSON_Delete(root);
	free(json);
	return retcode;
}


void timer_count()
{
	time_t t = time(NULL);
	struct tm tm = *localtime(&t);
	
	timer_shm->yyyy = tm.tm_year+1900;
	timer_shm->mm = tm.tm_mon+1;
	timer_shm->md = tm.tm_mday;
	timer_shm->hour = tm.tm_hour;
	timer_shm->min = tm.tm_min;
	timer_shm->sec = tm.tm_sec;
}


int main(int argc, char *argv[])
{
	int dev_shmid;
	int timer_shmid;
	int set_shmid;

//=========================================================================================	
	dev_shmid = shmget((key_t)DEV_SHM_KEY, sizeof(char), 0666 | IPC_CREAT);
	if(dev_shmid == -1)
	{
		perror("dev shmget fail");
		exit(0);
	}
	dev_shared_memory = shmat(dev_shmid, (void *)0, 0);
	if(dev_shared_memory == (void *)-1)
	{
		perror("dev shmat fail");
		exit(0);
	}
	dev_shm = (struct _dev *)dev_shared_memory;	
//=========================================================================================

//=========================================================================================	
	timer_shmid = shmget((key_t)TIMER_SHM_KEY, sizeof(char), 0666 | IPC_CREAT);
	if(timer_shmid == -1)
	{
		perror("timer shmget fail");
		exit(0);
	}
	timer_shared_memory = shmat(timer_shmid, (void *)0, 0);
	if(timer_shared_memory == (void *)-1)
	{
		perror("timer shmat fail");
		exit(0);
	}
	timer_shm = (struct _timer *)timer_shared_memory;	
//=========================================================================================

//=========================================================================================
	set_shmid = shmget((key_t)SET_SHM_KEY, sizeof(char), 0666 | IPC_CREAT);
	if(set_shmid == -1)
	{
		perror("set shmget fail");
		exit(0);
	}
	set_shared_memory = shmat(set_shmid, (void *)0, 0);
	if(set_shared_memory == (void *)-1)
	{
		perror("set shmat fail");
		exit(0);
	}
	set_shm = (struct _set_Value *)set_shared_memory;
//=========================================================================================
	
	while(1)
	{
		sleep(1);
		timer_count();
		
		if(timer_shm->min != old_min)
		{
			old_min = timer_shm->min;
			
			if(curl_global_init(CURL_GLOBAL_ALL)) {
				fprintf(stderr, "Fatal: The initialization of libcurl has failed.\n");
				return EXIT_FAILURE;
			}
	
			if(atexit(curl_global_cleanup)) {
				fprintf(stderr, "Fatal: atexit failed to register curl_global_cleanup.\n");
				curl_global_cleanup();
				return EXIT_FAILURE;
			}
			
			if(dev_shm->polling_flag == 1)
			{
				if(!PostJSON(_status_item)) {
					fprintf(stderr, "Fatal: PostJSON failed.\n");
					return EXIT_FAILURE;
				}
			}			
		}
	}
	
	
	 return EXIT_SUCCESS;
}

참고로 crt 인증서의 경우 해당 인증서 경로에 접속해야하는 서버의 인증서를 직접 받는 방법과

리눅스에서 해당 서버인증서를 확인하여 긁어오는 방법도 있다.

나 같은 경우는 직접 인증서를 해당사이트에 가서 긁어오는 방식을 택해서 작업을 하였다.

git에 cJson을 활용한 부분이고 json의 경우 여러가지 lib과 또는 직접 구현해도 별로 어렵지 않으니 ..

위 소스의 경우 공유메모리를 사용하는 부분이 포함되어 있으니 이부분은 제외하면 될꺼같다. 

프로세스가 3개이상 동작중에 데이터를 서로 공유해야하는 상황때문에 이렇게 코딩을 하였으니 참고바람.

이상