c - 用 json-c 在 C 中构造 json 对象

Question

我是 json-c 的新手。

我能够以以下格式创建 JSON 对象：

{"loglevel":"INFO", "msg":"Info about car", "timestamp":"actual system time"}

但我需要帮助以以下格式创建 JSON 对象：

{"module":"log","version":1.0, "logs":[{"loglevel":"INFO", "msg":"Info about car", "timestamp":"actual system time"}]}

代码如下：

/*Line is the messge of string which is passed from other module*/
static void json_file(char *line)
{
    FILE* lg;
    lg = fopen(JSON_FILE,"ab+");

    char *json = "{\"key1\":\"data\", \"key2\":1.0, \"Logs\":[";
    fwrite(line, sizeof(char), strlen(line),lg);
    fputs("]}", lg);
    /*replace last ']}' with ',' json string and ]} */
    char stringtofind[4] = "]}";
    char get_line[2000];
    fgets(get_line, sizeof(get_line), lg);
    if (strstr(get_line, stringtofind) != NULL)
    {
        printf("substring found \n");
        /* Help Required here*/
        /* please help */
        // Need to replace the  "]}" into ","
    }
}

Answer 1

据我了解，您想使用 json-c，对吗？那为什么不使用真正的语法呢？

#include <stdio.h>
#include <json-c/json.h>




json_object *generate_log_object(char *log_level, char *msg, char *timestamp){
   // {}
   json_object *child = json_object_new_object();
   //  {"loglevel": ... }
   json_object_object_add(child, "loglevel", json_object_new_string(log_level));
   // {"loglevel":"...", "msg":"..."}
   json_object_object_add(child, "msg", json_object_new_string(msg));
   // {"loglevel":"...", "msg":"...", "timestamp":"..."}
   json_object_object_add(child, "timestamp", json_object_new_string(timestamp));
   return child
}



int main(void)
{
   json_object *root = json_object_new_object();
   if (!root)
      return 1;
   // {"module":"log"}
   json_object_object_add(root, "module", json_object_new_string("log"));

   // {"module":"log","version":1.0 }
   json_object_object_add(root, "version", json_object_new_string("1.0"));


   // {"module":"log","version":1.0, "logs":[]}
   json_object *logs = json_object_new_array();
   json_object_object_add(root, "logs", logs);


   // {"module":"log","version":1.0, "logs":[{"loglevel":"INFO", "msg":"Info about car", "timestamp":"actual system time"}]}
   char *log1 = generate_log_object("INFO", "Info about car", "system time");
   json_object_array_add(children, log1);
}

顺便说一句，在过去的 5 年里我没有使用 C 并且我从未使用过json-c. 我没有编译代码，所以可能有一些拼写错误，或者我让你修复的小错误。