Add new feat. to support construct a json-rpc request

Author: sfxfs

example/invoke_a_func/invoke_a_func.c

@@ -19,8 +19,8 @@ int main()
     // Add a method
     mjrpc_add_method(handle, hello_world, "hello", NULL);
 
-    // Construct a JSON-RPC request
-    const char* json_request = "{\"jsonrpc\":\"2.0\",\"method\":\"hello\",\"id\":1}";
+    // Construct a JSON-RPC request: {"jsonrpc":"2.0","method":"hello","id":1}
+    char* json_request = mjrpc_request_str("hello", NULL, cJSON_CreateNumber(1));
     char* json_response = NULL;
 
     // Process the request
@@ -33,7 +33,9 @@ int main()
     assert(json_response != NULL);
 
     // show the response
+    printf("Request: %s\n", json_request);
     printf("Response: %s\n", json_response);
+    free(json_request);
     free(json_response);
 
     // Cleanup

src/mjsonrpc.c

@@ -187,6 +187,35 @@ static cJSON* rpc_handle_ary_req(const mjrpc_handle_t* handle, const cJSON* requ
 
 /*--- main functions ----*/
 
+cJSON* mjrpc_request_cjson(const char* method, cJSON* params, cJSON* id)
+{
+    if (method == NULL)
+        return NULL;
+
+    cJSON* json = cJSON_CreateObject();
+    if (json == NULL)
+        return NULL;
+
+    cJSON_AddStringToObject(json, "jsonrpc", "2.0");
+    cJSON_AddStringToObject(json, "method", method);
+    cJSON_AddItemToObject(json, "params", params);
+    cJSON_AddItemToObject(json, "id", id);
+
+    return json;
+}
+
+char* mjrpc_request_str(const char* method, cJSON* params, cJSON* id)
+{
+    cJSON* json = mjrpc_request_cjson(method, params, id);
+    if (json == NULL)
+        return NULL;
+
+    const char* json_str = cJSON_PrintUnformatted(json);
+    cJSON_Delete(json);
+
+    return json_str;
+}
+
 cJSON* mjrpc_response_ok(cJSON* result, cJSON* id)
 {
     if (id == NULL || result == NULL)

src/mjsonrpc.h

@@ -76,6 +76,30 @@ typedef struct mjrpc_handle
     size_t size;
 } mjrpc_handle_t;
 
+
+/* --- For client --- */
+
+/**
+ * @brief build a jsonrpc string request
+ * @param method name of method
+ * @param params parameters for the method
+ * @param id request id, can be NULL for notification
+ * @return string pointer
+ */
+char* mjrpc_request_str(const char* method, cJSON* params, cJSON* id);
+
+/**
+ * @brief build a jsonrpc cjson request
+ * @param method name of method
+ * @param params parameters for the method
+ * @param id request id, can be NULL for notification
+ * @return cjson pointer
+ */
+cJSON* mjrpc_request_cjson(const char* method, cJSON* params, cJSON* id);
+
+
+/* --- For server --- */
+
 /**
  * @brief build a jsonrpc response with result
  * @param result call result