Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. JSON parsing with QtJson...
Forum Update on Monday, May 27th 2025

JSON parsing with QtJson...

Scheduled Pinned Locked Moved Solved General and Desktop
22 Posts 7 Posters 3.6k Views
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • Christian EhrlicherC Christian Ehrlicher

    @filipdns said in JSON parsing with QtJson...:

    what I have to do to extract the data what I need?...

    Extract the array I would guess... http://doc.qt.io/qt-5/qjsonarray.html

    F Offline
    F Offline
    filipdns
    wrote on last edited by
    #10

    @Christian-Ehrlicher I try to work with it like array:

    var obj =JSON.parse(res)
    console.log(obj.aircraft[0].geography)

    but the return message is [object Object]...

    kshegunovK 1 Reply Last reply
    0
    • Christian EhrlicherC Offline
      Christian EhrlicherC Offline
      Christian Ehrlicher
      Lifetime Qt Champion
      wrote on last edited by Christian Ehrlicher
      #11

      Sorry but I don't understand python that much to help you.

      Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
      Visit the Qt Academy at https://academy.qt.io/catalog

      1 Reply Last reply
      0
      • mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by
        #12

        Hi

        {
          "aircraft":[
            {
              "geography":{
                "latitude":42.6581,
                "longitude":5.51009,
                "altitude":11585.4,
                "direction":16
              },
              "speed":{
                "horizontal":861.641,
                "isGround":0,
                "vertical":0
              },
              "departure":{
                "iataCode":"DJE",
                "icaoCode":"DTTJ"
              },
              "arrival":{
                "iataCode":"ORY",
                "icaoCode":"LFPO"
              },
              "aircraft":{
                "regNumber":"FGZHS",
                "icaoCode":"B738",
                "icao24":"3964F2",
                "iataCode":"B738"
              },
              "airline":{
                "iataCode":"TO",
                "icaoCode":"TVF"
              },
              "flight":{
                "iataNumber":"TO3875",
                "icaoNumber":"TVF3875",
                "number":"3875"
              },
              "system":{
                "updated":"1543087861",
                "squawk":"7376"
              },
              "status":"started"
            }
          ]
        }
        

        Would obj.aircraft[0].geography
        not be an object ? with keys latitude,longitude etc ?

        1 Reply Last reply
        0
        • F filipdns

          @Christian-Ehrlicher I try to work with it like array:

          var obj =JSON.parse(res)
          console.log(obj.aircraft[0].geography)

          but the return message is [object Object]...

          kshegunovK Offline
          kshegunovK Offline
          kshegunov
          Moderators
          wrote on last edited by
          #13

          Firstly, what is this language? JS?
          Secondly, what is JSON in your code and where does it come from?

          Read and abide by the Qt Code of Conduct

          F 1 Reply Last reply
          0
          • kshegunovK kshegunov

            Firstly, what is this language? JS?
            Secondly, what is JSON in your code and where does it come from?

            F Offline
            F Offline
            filipdns
            wrote on last edited by
            #14

            @kshegunov Hello,

            Yes, it's JS language to get the network response.

            the JSON response is come from http://aviation-edge.com

            with request like http://aviation-edge.com/v2/public/flights?key=2a8619-db5a5c&regNum=ECMJT

            kshegunovK 1 Reply Last reply
            0
            • F filipdns

              @kshegunov Hello,

              Yes, it's JS language to get the network response.

              the JSON response is come from http://aviation-edge.com

              with request like http://aviation-edge.com/v2/public/flights?key=2a8619-db5a5c&regNum=ECMJT

              kshegunovK Offline
              kshegunovK Offline
              kshegunov
              Moderators
              wrote on last edited by
              #15

              I am now completely confused. How and why is this JS executed and what relation does it bear to Qt? Is this a QML function?

              Read and abide by the Qt Code of Conduct

              F 1 Reply Last reply
              0
              • kshegunovK kshegunov

                I am now completely confused. How and why is this JS executed and what relation does it bear to Qt? Is this a QML function?

                F Offline
                F Offline
                filipdns
                wrote on last edited by
                #16

                @kshegunov Hi, it has no link with qt, it's just in case some one can help me to parse JSON with keys.

                But did what I need parsing in JS but it's not very beautiful code like it is example:

                                res=doc.responseText//JS.data(doc.responseText)
                                //console.log(res)
                                //var obj =JSON.parse(res)
                                var error="{\"error\": \"No Record Found or Flight not currently detected by receivers. \" }"
                                if(res!==error)
                                {
                                    var res1=res.replace("[","")
                                    var res2=res1.replace("{","")
                                    var res3=res2.split("{")
                                    var res4=res3[1]
                                    var res5= res4.split(",")
                                    var res6=res5[0]+res5[1]+res5[2]+res5[3]
                                    var res7=res6
                                    var res8=res7.replace("\n","")
                                    var res9=res8.replace("            ","")
                                    var res10=res9.replace("\"","")
                                    var res11=res10.split(":")
                                    var res12=res11[0].replace("\"","") //text: latitude
                                    var res13=res11[1].split("\n")
                                    var res14=parseFloat(res13[0])      //valeur latitude
                                    var res15=res13[1].replace("            \"","")
                                    var res16=res15.replace("\"","")    //text longitude
                                    var res17=parseFloat(res11[2].split("\n")[0])// valeur longitude
                                    var res18=parseInt(parseFloat(res11[3].split("\n")[0])*3.28084/100) // valeur altitude
                                    var res19 = parseInt(res11[4].split("\n")[0]) // valeur cap
                
                1 Reply Last reply
                0
                • F filipdns

                  Hello,

                  I'm trying to parse value from JSON file:

                  [ { "geography": { "latitude": 51.1392, "longitude": 11.1481, "altitude": 11280.5, "direction": 68.9 }, "speed": { "horizontal": 805.37, "isGround": 0, "vertical": -3.90144 }, "departure": { "iataCode": "BVA", "icaoCode": "LFOB" }, "arrival": { "iataCode": "CIA", "icaoCode": "LIRA" }, "aircraft": { "regNumber": "EIGDT", "icaoCode": "B738", "icao24": "", "iataCode": "B738" }, "airline": { "iataCode": "FR", "icaoCode": "RYR" }, "flight": { "iataNumber": "FR92QB", "icaoNumber": "RYR92QB", "number": "92QB" }, "system": { "updated": "1543065538", "squawk": "1127" }, "status": "en-route" }, { "geography": { "latitude": 43.4357, "longitude": 18.9397, "altitude": 11280.5, "direction": 136 }, "speed": { "horizontal": 914.949, "isGround": 0, "vertical": -5.20192 }, "departure": { "iataCode": "BVA", "icaoCode": "LFOB" }, "arrival": { "iataCode": "SKG", "icaoCode": "LGTS" }, "aircraft": { "regNumber": "EIEKI", "icaoCode": "B738", "icao24": "4CA808", "iataCode": "B738" }, "airline": { "iataCode": "FR", "icaoCode": "RYR" }, "flight": { "iataNumber": "FR3094", "icaoNumber": "RYR3094", "number": "3094" }, "system": { "updated": "1543065479", "squawk": "664" }, "status": "en-route" } ]
                  

                  with

                  
                     QByteArray data= reply->readAll();
                     QString datastring = QString::fromStdString(data.toStdString());
                      //qDebug()<<data;
                  
                      bool ok;
                      // datastring is a QString containing the JSON data
                      QtJson::JsonObject result = QtJson::parse(datastring, ok).toMap();
                  
                      if(!ok) {
                        qFatal("An error occurred during parsing");
                      }
                  
                      qDebug() << "latitude:" << result["latitude"].toString();
                  

                  but the result say only:

                  latitude: ""

                  What I did wrong?

                  [Moved to General and Desktop ~kshegunov]

                  Taz742T Offline
                  Taz742T Offline
                  Taz742
                  wrote on last edited by
                  #17

                  @filipdns
                  It is not a valid json file. https://forum.qt.io/topic/64314/json-access-data-in-multidimensional-arrays/8

                  Do what you want.

                  F 1 Reply Last reply
                  3
                  • Taz742T Taz742

                    @filipdns
                    It is not a valid json file. https://forum.qt.io/topic/64314/json-access-data-in-multidimensional-arrays/8

                    F Offline
                    F Offline
                    filipdns
                    wrote on last edited by
                    #18

                    @Taz742 thank you, I will stay with my poor code then lol

                    aha_1980A 1 Reply Last reply
                    0
                    • F filipdns

                      @Taz742 thank you, I will stay with my poor code then lol

                      aha_1980A Offline
                      aha_1980A Offline
                      aha_1980
                      Lifetime Qt Champion
                      wrote on last edited by
                      #19

                      @filipdns

                      Did you read the post @Taz742 linked?

                      Your top-level structure is a JSON array, so you must convert the document to a QJsonArray, not a QJsonObject.

                      Using a QJsonArray should work for you, too.

                      Qt has to stay free or it will die.

                      F 1 Reply Last reply
                      1
                      • aha_1980A aha_1980

                        @filipdns

                        Did you read the post @Taz742 linked?

                        Your top-level structure is a JSON array, so you must convert the document to a QJsonArray, not a QJsonObject.

                        Using a QJsonArray should work for you, too.

                        F Offline
                        F Offline
                        filipdns
                        wrote on last edited by filipdns
                        #20

                        @aha_1980 Hello, I start to read yes, I'm trying to understand how do that in js, I found documentation on QJsonArray only for c++ at the moment

                        kshegunovK 1 Reply Last reply
                        0
                        • F filipdns

                          @aha_1980 Hello, I start to read yes, I'm trying to understand how do that in js, I found documentation on QJsonArray only for c++ at the moment

                          kshegunovK Offline
                          kshegunovK Offline
                          kshegunov
                          Moderators
                          wrote on last edited by kshegunov
                          #21

                          In JS you just parse it, as it's a natively supported.

                          var myJson = JSON.eval(jsonText);
                          

                          If it's a valid json, then properties are available directly as any other java script object, or in your case:

                          var obj =JSON.parse(res);
                          console.log("Latitude: " + obj.aircraft[0].geography.latitude);
                          

                          I still don't get the relevance, though.

                          Read and abide by the Qt Code of Conduct

                          1 Reply Last reply
                          2
                          • M Offline
                            M Offline
                            makcorps
                            Banned
                            wrote on last edited by
                            #22
                            This post is deleted!
                            1 Reply Last reply
                            0

                            • Login

                            • Login or register to search.
                            • First post
                              Last post
                            0
                            • Categories
                            • Recent
                            • Tags
                            • Popular
                            • Users
                            • Groups
                            • Search
                            • Get Qt Extensions
                            • Unsolved