/*********************************************************************************
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* Copyright: (C) 2023 LingYun IoT System Studio.
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* All rights reserved.
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*
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* Filename: pack_json.c
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* Description: This file is JSON format string package and parser example
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*
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* Version: 1.0.0(2023年07月10日)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "2023年07月10日 17时57分00秒"
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*
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********************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <cjson/cJSON.h>
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#define DEVSN_LEN 11
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typedef struct data_s
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{
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char devsn[DEVSN_LEN+1];
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char time[32];
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float temp;
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float rh;
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} pack_t;
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int pack_json(char *buf, int size, char *devsn, char *time, float temp, float rh);
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int unpack_json(char *buf, int len, pack_t *pack);
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int main (int argc, char **argv)
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{
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char buf[512];
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char *devsn="ISK1023001";
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char *time="2023-07-10 20:00:00";
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float temp = 20.50;
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float rh = 30.50;
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pack_t data;
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int rv;
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if( (rv=pack_json(buf, sizeof(buf), devsn, time, temp, rh)) < 0 )
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{
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printf("Package sample data message failed, rv=%d\n", rv);
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return rv;
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}
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if( (rv=unpack_json(buf, rv, &data)) < 0 )
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{
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printf("Parser sample data message failed, rv=%d\n", rv);
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return rv;
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}
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return 0;
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}
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int pack_json(char *buf, int size, char *devsn, char *time, float temp, float rh)
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{
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if( !buf || size<=0 || !devsn || !time )
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{
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printf("\033[1;31m%s:%d %s() Invalid input arguments\033[0m\n", __FILE__, __LINE__, __func__);
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return -1;
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}
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memset(buf, 0, size);
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snprintf(buf, size, "{\"devsn\":\"%s\", \"time\":\"%s\", \"temperature\":%.2f, \"humidity\":%.2f}", devsn, time, temp, rh);
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printf("\033[1;32mPacket Message: %s\033[0m\n", buf);
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return strlen(buf);
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}
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int unpack_json(char *buf, int len, pack_t *pack)
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{
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cJSON *root = NULL;
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cJSON *item;
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char *value;
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int bytes;
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int rv = 0;
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if( !buf || len<=0 || !pack )
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{
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printf("\033[1;31m%s:%d %s() Invalid input arguments\033[0m\n", __FILE__, __LINE__, __func__);
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return -1;
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}
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printf("\033[1;33mParser Message: %s\033[0m\n", buf);
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root = cJSON_Parse(buf);
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if( !root )
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{
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printf("cJSON_Parse root failure: %s\n", cJSON_GetErrorPtr());
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return -2;
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}
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memset(pack, 0, sizeof(*pack));
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/*+--------------------------+
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*| Start parser SN segement |
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*+--------------------------+*/
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item = cJSON_GetObjectItem(root, "devsn");
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if( !item )
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{
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printf("cJSON_GetObjectItem() item failure: %s\n", cJSON_GetErrorPtr());
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rv = -3;
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goto cleanup;
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}
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bytes = strlen(item->valuestring);
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bytes = bytes>sizeof(pack->devsn) ? sizeof(pack->devsn) : bytes;
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strncpy(pack->devsn, item->valuestring, bytes);
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printf("Found devsn : %s\n", pack->devsn);
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/*+----------------------------+
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*| Start parser Time segement |
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*+----------------------------+*/
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item = cJSON_GetObjectItem(root, "time");
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if( !item )
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{
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printf("cJSON_GetObjectItem() item failure: %s\n", cJSON_GetErrorPtr());
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rv = -4;
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goto cleanup;
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}
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bytes = strlen(item->valuestring);
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bytes = bytes>sizeof(pack->time) ? sizeof(pack->time) : bytes;
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strncpy(pack->time, item->valuestring, bytes);
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printf("Found time : %s\n", pack->time);
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/*+--------------------------+
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*| Start parser temperature |
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*+--------------------------+*/
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item = cJSON_GetObjectItem(root, "temperature");
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if( !item )
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{
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printf("cJSON_GetObjectItem() item failure: %s\n", cJSON_GetErrorPtr());
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rv = -5;
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goto cleanup;
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}
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pack->temp = item->valuedouble;
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printf("Found temperature: %.2f\n", pack->temp);
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/*+-----------------------+
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*| Start parser humidity |
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*+-----------------------+*/
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item = cJSON_GetObjectItem(root, "humidity");
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if( !item )
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{
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printf("cJSON_GetObjectItem() item failure: %s\n", cJSON_GetErrorPtr());
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rv = -6;
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goto cleanup;
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}
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pack->rh = item->valuedouble;
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printf("Found humidity : %.2f\n", pack->rh);
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cleanup:
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cJSON_Delete(root); /* must delete it, or it will result memory leak */
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return rv;
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}
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