Check an IP address against an online list in Inno Setup

Question

I am getting the user IP address using the below code

function GetIp: string;
var
  WinHttpReq: Variant;
begin
    try
      WinHttpReq := CreateOleObject('WinHttp.WinHttpRequest.5.1');
      WinHttpReq.Open('GET', 'http://ipinfo.io/ip', False);
      WinHttpReq.Send;
      Result := Trim(WinHttpReq.ResponseText);
    except
      Log(GetExceptionMessage);
      Result := '8.8.8.8';
    end;
end;

After getting the users IP address I need to check if that IP address already exists in my online JSON list.

Thanks

Answer 1

The simplest solution is to download your JSON text file and search your IP address.

Reuse your code to retrieve a document using HTTP (or better HTTPS):

function HttpGet(Url: string): string;
var
  WinHttpReq: Variant;
begin
  WinHttpReq := CreateOleObject('WinHttp.WinHttpRequest.5.1');
  WinHttpReq.Open('GET', Url, False);
  WinHttpReq.Send;
  Result := Trim(WinHttpReq.ResponseText);
end;

And then you can use it like:

var
  Ip: string;
  List: string;
begin
  try
    Ip := HttpGet('https://ipinfo.io/ip');
    List := HttpGet('https://www.example.com/publicly/available/list.json');

    if Pos('["' + Ip + '"]', List) > 0 then
    begin
      Log(Format('IP %s is in the list', [Ip]));
    end
      else
    begin
      Log(Format('IP %s is not in the list', [Ip]));
    end;
  except
    Log(Format('Error testing if IP is in the list - %s', [GetExceptionMessage]));
  end;
end;

Though you will have to make your list publicly available. Currently your URL cannot be accessed, without logging to Google first.

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If you want to process your JSON properly, see
How to parse a JSON string in Inno Setup?