HTTP.post versus downloadURL using Delphi XE2 - delphi

Question

I am trying to use the same procedure for two types of downloads. both are working.
I would like to use TDownloadURL or HTTP.Post on both, but cannot determine how. Which method and how to do this? Thank you.
First operation --
procedure TfrmMain.get1Click(Sender: TObject);
var
json: string;
lHTTP: TIdHTTP;
lParamList: TStringList;
result:string;
begin
json := CRLF +
'{' + CRLF +
' "resource_id": "391792b5-9c0a-48a1-918f-2ee63caa1c54",' + CRLF +
' "filters": {' + CRLF +
' "provider_id": 393303' + CRLF +
' }' + CRLF +
'}';
lParamList := TStringList.Create;
try
lParamList.Add('somename='+json);
lHTTP := TIdHTTP.Create(nil);
try
Result := lHTTP.Post('http://hub.Healthdata.gov/api/action/datastore_search', lParamList);
finally
lHTTP.Free;
end;
finally
lParamList.Free;
end;
end;
Second operation --
procedure TfrmMain.get2Click(Sender: TObject);
var
dl: TDownloadURL;
url:string;
begin
url:='http://api.census.gov/data/2010/sf1?key=KEY&get=P0010001,NAME&for=state:*';
dl := TDownloadURL.Create(self);
try
dl.URL := url;
dl.FileName := execpath+'api1.txt'; dl.ExecuteTarget(nil); dl.Free;
except
dl.Free;
end;
end;

Answer 1

TDownloadURL uses the GET HTTP method. TIdHTTP.Post obviously uses the POST method. In general, neither is appropriate for use in place of the other. That's why both methods exist in the first place.
A POST request can include all the information that a GET request does, plus more, which makes it seem like it should be able to do everything GET can do, plus more. However, servers are not required to (and should not be expected to) handle POST requests the same way they do GET.
As the one writing the HTTP client, you're not really in control of the situation. The server dictates which methods it will honor. Clients need to either do what's expected of them or be denied access.
The Indy components support both methods, so if you just want to make your POST code and your GET code look similar, then you can replace TDownloadURL with TIdHTTP.Get.