Delphi - idHTTP upload file using TIdMultipartFormDataStream - delphi

Question

I'm trying to upload a file using TIdHTTP. The problem is the access token gets changed when the request is sent to the server.
The access token that I'm using is fJNhDM6TlcpeVmD8h3jFuPJS71sxwZB8bZBXajTRB5TNAcRa6PNXfv4J7mPxIvMdMhjy7oKdTLbsRYthpBCCqGVkj4vlojJ4BRBkLAVIBJ1DZAnMZD
The API returns
HTTP/1.1 400 Bad Request
OAuth "invalid_token" "Malformed access token fJNhDM6TlcpeVmD8h3jFu=\r\nPJS71sxwZB8bZBXajTRB5TNAcRa6PNXfv4J7mPxIvMdMhjy7oKdTLbsRYthpBCCqGVkj4v=\r\nlojJ4BRBkLAVIBJ1DZAnMZD"
There is =\r\n added to my token twice.
My code is:
function TFoo.Post(const AToken, guID, AMessage, AImageFileName: string): Boolean;
var
lParam : TIdMultipartFormDataStream;
begin
Result := False;
if not FileExists(AImageFileName) then begin
LastError := 'File not found ' + AImageFileName;
Exit;
end;
ProxyCheck;
lParam := TIdMultipartFormDataStream.Create;
try
lParam.AddFormField('message', AMessage);
lParam.AddFormField('access_token', AToken);
lParam.AddFile('source', AImageFileName);
idHTTP.Request.ContentType := 'application/x-www-form-urlencoded';
try
idHTTP.Post( UrlAPI + guID + '/photos', lParam);
Result := True;
except;
LastError := idHTTP.ResponseText + sLineBreak + idHTTP.Response.WWWAuthenticate.Text;
end;
finally
lParam.Free;
end;
end;
What am I missing here ?

Answer 1

By default, AddFormField() sets the TIdFormDataField.ContentTransfer property to MIME's quoted-printable format. That is where the extra =\r\n is coming from. It is a "soft" line break being inserted by quoted-printable every 76 characters. Any server that supports quoted-printable would remove "soft" line breaks during decoding. But maybe your server does not.
If you want to disable the quoted-printable behavior, you can set the ContentTransfer property to either:
a blank string:
lParam.AddFormField('access_token', AToken).ContentTransfer := '';
'7bit' (since it does not contain any non-ASCII characters):
lParam.AddFormField('access_token', AToken).ContentTransfer := '7bit';
'8bit' or binary:
lParam.AddFormField('access_token', AToken).ContentTransfer := '8bit';
lParam.AddFormField('access_token', AToken).ContentTransfer := 'binary';
In this case, I would suggest #1.
On a side note, do not set the HTTP content type when posting a TIdMultipartFormDataStream. Not only are you using the wrong media type to begin with (it should be multipart/form-data instead), but the TIdMultipartFormDataStream version of Post() will simply overwrite it anyway.
function TFoo.Post(const AToken, guID, AMessage, AImageFileName: string): Boolean;
var
lParam : TIdMultipartFormDataStream;
begin
Result := False;
if not FileExists(AImageFileName) then begin
LastError := 'File not found ' + AImageFileName;
Exit;
end;
ProxyCheck;
lParam := TIdMultipartFormDataStream.Create;
try
lParam.AddFormField('message', AMessage);
lParam.AddFormField('access_token', AToken).ContentTransfer := '';
lParam.AddFile('source', AImageFileName);
try
idHTTP.Post(UrlAPI + guID + '/photos', lParam);
Result := True;
except;
LastError := idHTTP.ResponseText + sLineBreak + idHTTP.Response.WWWAuthenticate.Text;
end;
finally
lParam.Free;
end;
end;