c++jsonmql4mt4

Remove carriage return from json text


I get json text returned from an api call and I run it trough a script JSON Serialization and Deserialization from here https://www.mql5.com/en/code/13663.

My issue is that it only process the first few parts of the json because of what I believe to a linebreak/carriage inside the json structure. I dont get any error message, just an array containing everything before that line break.

I dont want to remove the line breaks inside the text fields in the json, only the returns inside the json structure. It is in the place each time just after {"ok":true,"result":[{"update_id":568022212,

Here is a full section

{"ok":true,"result":[{"update_id":568022212,
"channel_post":{"message_id":436,"chat":{"id":-1001436032340,"title":"FORTUNA","type":"channel"},"date":1588899840,"reply_to_message":{"message_id":372,"chat":{"id":-1001436032340,"title":"FORTUNA","type":"channel"},"date":1588838583,"text":"A\nGbpusd buy now 1.2360\nSl 1.2280 \nTp open\n","entities":[{"offset":52,"length":11,"type":"mention"}]},"text":"A\n42 pips bookd close\ud83d\udfe2\ud83d\udfe2"}},{"update_id":568022213,
"channel_post":{"message_id":437,"chat":{"id":-1001436032340,"title":"FORTUNA","type":"channel"},"date":1588900321,"reply_to_message":{"message_id":435,"chat":{"id":-1001436032340,"title":"FORTUNA","type":"channel"},"date":1588893671,"text":"A\nGold buy 1713.3\nSl 1702 \nTp open\nSwing trade"},"text":"Amazon\n60 pips bookd close\ud83d\udfe2\ud83d\udfe2"}},{"update_id":568022214,
"channel_post":{"message_id":438,"chat":{"id":-1001436032340,"title":"FORTUNA","type":"channel"},

MQL4 code:

 int   GetUpdates()
     {
      if(m_token==NULL)
         return(ERR_TOKEN_ISEMPTY);

      string out;
      string url=StringFormat("%s/bot%s/getUpdates",TELEGRAM_BASE_URL,m_token);
      string params=StringFormat("offset=%d",m_update_id);
      //---
      int res=PostRequest(out,url,params,WEB_TIMEOUT);
      if(res==0)
        {

         Print(StringDecode(out));
         //--- parse result
         CJAVal js(NULL,jtUNDEF);
         bool done=js.Deserialize(out);
         if(!done)
            return(ERR_JSON_PARSING);

         bool ok=js["ok"].ToBool();
         if(!ok)
            return(ERR_JSON_NOT_OK);

         CCustomMessage msg;

         int total=ArraySize(js["result"].m_e);
         for(int i=0; i<total; i++)
           {
            CJAVal item=js["result"].m_e[i];
            //---
            msg.update_id=item["update_id"].ToInt();

            //---
            msg.message_id=item["message"]["message_id"].ToInt();
            msg.message_date=(datetime)item["message"]["date"].ToInt();
            //---
            msg.message_text=item["message"]["text"].ToStr();
            printf((datetime)item["message"]["date"].ToInt());
            msg.message_text=StringDecode(msg.message_text);
            //---
            msg.from_id=item["message"]["from"]["id"].ToInt();

            msg.from_first_name=item["message"]["from"]["first_name"].ToStr();
            msg.from_first_name=StringDecode(msg.from_first_name);

            msg.from_last_name=item["message"]["from"]["last_name"].ToStr();
            msg.from_last_name=StringDecode(msg.from_last_name);

            msg.from_username=item["message"]["from"]["username"].ToStr();
            msg.from_username=StringDecode(msg.from_username);
            //---
            msg.chat_id=item["message"]["chat"]["id"].ToInt();

            msg.chat_first_name=item["message"]["chat"]["first_name"].ToStr();
            msg.chat_first_name=StringDecode(msg.chat_first_name);

            msg.chat_last_name=item["message"]["chat"]["last_name"].ToStr();
            msg.chat_last_name=StringDecode(msg.chat_last_name);

            msg.chat_username=item["message"]["chat"]["username"].ToStr();
            msg.chat_username=StringDecode(msg.chat_username);

Solution

  • I tried to use the same library, it seems to have a bug with parsing arrays. That is why I used https://www.mql5.com/en/code/11134. It has a disadvantage: you need to delete all the objects, unfortunately; as a result there's plenty of code. But at least it works.

    Seems your json has incorrect format, I used to cut it a little.

      #include <json1.mqh> //modified version, https://www.mql5.com/en/forum/28928/page5#comment_15766620
    
      //const string post_result=
      //{"ok":true,"result":[
      //{"update_id":568022212,"channel_post":{"message_id":436,"chat":{"id":-1001436032340,"title":"FORTUNA","type":"channel"},
      //"date":1588899840,"reply_to_message":{"message_id":372,"chat":{"id":-1001436032340,"title":"FORTUNA","type":"channel"},
      //"date":1588838583,"text":"A\nGbpusd buy now 1.2360\nSl 1.2280 \nTp open\n","entities":[{"offset":52,"length":11,"type":"mention"}]},"text":"A\n42 pips bookd close\ud83d\udfe2\ud83d\udfe2"}},
      //{"update_id":568022213,"channel_post":{"message_id":437,"chat":{"id":-1001436032340,"title":"FORTUNA","type":"channel"},
      //"date":1588900321,"reply_to_message":{"message_id":435,"chat":{"id":-1001436032340,"title":"FORTUNA","type":"channel"},
      //"date":1588893671,"text":"A\nGold buy 1713.3\nSl 1702 \nTp open\nSwing trade"},"text":"Amazon\n60 pips bookd close\ud83d\udfe2\ud83d\udfe2" }}]}
      //;
    
    
    void function()
      {
    //---
      const string post_result=getContent();//ok, you managed to get some string here
    
      JSONParser *parser=new JSONParser();
      JSONValue *value=parser.parse(post_result);
      delete(parser);
      if(CheckPointer(value)==POINTER_INVALID)
        {
         printf("%i %s: error!",__LINE__,__FILE__);
         delete(value);
         return;
        }
      JSONObject *obj=(JSONObject*)value;
      const bool isSuccess=obj.getBool("ok");
      printf("%i %s: isSuccess=%d",__LINE__,__FILE__,isSuccess);
      if(!isSuccess)return;
    
      JSONValue *resultValue=obj.getValue("result");
      if(CheckPointer(resultValue)!=POINTER_INVALID)
        {
         JSONArray *resultValueArray=resultValue;
         for(int i=0;i<resultValueArray.size();i++)
           {
            printf("%i %s: #%d=%s",__LINE__,__FILE__,i,resultValueArray.getObject(i).toString());
            //you can work with JSONObject or with string, whatever is more convenient
            parseResultLine(resultValueArray.getObject(i));
           }
         delete(resultValueArray);
        }
      delete(resultValue);
      delete(obj);
    }   
      bool parseResultLine(JSONObject *object)
        {
         const long update_id=object.getLong("update_id");
         JSONObject *channel_post=object.getObject("channel_post");
    
         const long message_id=channel_post.getLong("message_id");
         const datetime date=(datetime)channel_post.getInt("date");
         const string text=channel_post.getString("text");
      printf("%i %s: id=%s, dt=%d/%s, text=%s",__LINE__,__FILE__,IntegerToString(message_id),(int)date,TimeToString(date),text);
         JSONObject *chat=channel_post.getObject("chat");
         const long chat_id=chat.getLong("id");
         const string chat_title=chat.getString("title");
      printf("%i %s: chat-> id=%I64d title=%s type=%s",__LINE__,__FILE__,chat_id,chat_title,chat.getString("type"));
         JSONObject *reply=channel_post.getObject("reply_to_message");
      printf("%i %s: replied: id=%s, date=%s",__LINE__,__FILE__,string(reply.getLong("message_id")),TimeToString(reply.getInt("date")));
    
         return true;
        }