Receive JSON string via Socket

Question

I’m getting a stream with JSON strings and I’m showing on a Tmemo. It happens that I am not able to process the JSON correctly because not always comes the same amount of characters from the server. I would need to process the JSON and display the results in another TMEMO. I’ve heard of buffer, streams etc but I’m not familiar with them.

Note: Use Tclientsocket

procedure TForm1.csClienteRead(Sender: TObject; Socket:  TCustomWinSocket);
var
 data: String;
begin
 data := Socket.ReceiveText;
 memoResults.Lines.Add(data);     
end;

As soon as I connect the Customer’s connection I receive this data:

{ "age" : "0", "camera" : "0", "direction" : "===", "id" : "12", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1508328838" }
{ "age" : "0", "camera" : "0", "direction" : "===", "id" : "11", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1508328838" }
{ "age" : "1", "camera" : "0", "direction" : "===", "id" : "10", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1508328837" }
{ "age" : "1", "camera" : "0", "direction" : "===", "id" : "9", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1508328837" }
{ "age" : "2", "camera" : "0", "direction" : "===", "id" : "8", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1508328836" }
{ "age" : "2", "camera" : "0", "direction" : "===", "id" : "7", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1508328836" }
{ "age" : "3", "camera" : "0", "direction" : "===", "id" : "6", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1508328835" }
{ "age" : "3", "camera" : "0", "direction" : "===", "id" : "5", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1508328835" }
{ "age" : "4", "camera" : "0", "direction" : "===", "id" : "4", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1508328834" }
{ "age" : "4", "camera" : "0", "direction" : "===", "id" : "3", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1508328834" }
{ "age" : "16402735", "camera" : "0", "direction" : ">>>", "id" : "0", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1491926103" }
{ "age" : "16402735", "camera" : "0", "direction" : "===", "id" : "2", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1491926103" }
{ "age" : "16402736", "camera" : "0", "direction" : "===", "id" : "1", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1491926102" }
{ "age" : "16402736", "camera" : "0", "direction" : "===", "id" : "0", "plate" : "DEMOPLATE", "strength" : "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" : "AUTOPARKING", "timestamp" : "1491926102" }

After this starts coming line by line but sometimes everything comes together without line breaks. I need 1 JSON at a time otherwise the system does not process.

Answer 1

With the following code will organize JSON this way, example:

age:0
camera:0
Direction:===
id:12
Plate:DEMOPLATE
Strength:0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00
systemName:AUTOPARKING
timestamp:1508328838

I used two memos and a button for the code to work, in memo1 pasted the JSON response later in the onclick event of the button I created the code to handle the text, and write in memo2.

Code:

var APos: Integer;
    AText, AWord, AResult: String;
begin
  AResult := '';

  AText := Memo1.Text;
  While (Trim(AText) <> '') do
    Begin
      APos := Pos('"', AText);
      if (APos > 0) then
        begin
          AWord := Trim(AnsiMidStr(AText, 1, APos - 1));
          Delete(AText, 1, APos);
        end
      else
        Begin
          AWord := Trim(AText);
          AText := '';
        End;

      if (AWord <> ',') and (AWord <> '{') and (AWord <> '}') and (AWord <> '} {') then
        Begin
          AResult := AResult + AWord;
          AWord := '';
        End;

      if (AWord <> '') then
        Begin
          Memo2.Lines.Add(AResult);
          AResult := '';
        End;
    End;
End;

If you need the answers only separately, so:

{ "age" "0", "camera" "0", "Direction" "===", "id" "12", "Plate" "DEMOPLATE", "Strength" "0.66 - 1.00 0.90 1.00 0.66 1.00 0.90 1.00", "systemName" "AUTOPARKING", "timestamp" "1508328838" }

Use the following code:

var APosB, APosE: Integer;
    AText, AResult: String;
begin
  AResult := '';
  AText := Memo1.Text;
  While (Trim(AText) <> '') do
    Begin
      APosB := Pos('{', AText);
      APosE := Pos('}', AText);
      if (APosB > 0) and (APosE > 0) then
        begin
          AResult := Trim(AnsiMidStr(AText, APosB, APosE - 1));
          Delete(AText, 1, APosE);
        end
      else
        Begin
          AResult := Trim(AText);
          AText := '';
        End;

      Memo2.Lines.Add(AResult);
    End;
end;

Any questions in the code let me know.