How to send a file AND other POST data with Synapse

Question

Delphi used: 2007.

Hello,

I have a simple web page with two text input and one file input. Now, for the form to be sent, both the text inputs and the file input have to be filled. With Synapse, I know how to upload a file (HttpPostFile) and how to post data (HttpMethod). However, I don't know how to do both.

After looking at the source code of Synapse, I guess I have to "format" my data with boundaries or something like that. I guess I should have one boundary for my input file and another boundary for my text inputs. I found an article on the subject, but it's about sending email attachments. I tried to reproduce what they said with Synapse, with no results.

Code for HttpPostFile:

function HttpPostFile(const URL, FieldName, FileName: string;
  const Data: TStream; const ResultData: TStrings): Boolean;
var
  HTTP: THTTPSend;
  Bound, s: string;
begin
  Bound := IntToHex(Random(MaxInt), 8) + '_Synapse_boundary';
  HTTP := THTTPSend.Create;
  try
    s := '--' + Bound + CRLF;
    s := s + 'content-disposition: form-data; name="' + FieldName + '";';
    s := s + ' filename="' + FileName +'"' + CRLF;
    s := s + 'Content-Type: Application/octet-string' + CRLF + CRLF;
    WriteStrToStream(HTTP.Document, s);
    HTTP.Document.CopyFrom(Data, 0);
    s := CRLF + '--' + Bound + '--' + CRLF;
    WriteStrToStream(HTTP.Document, s);
    HTTP.MimeType := 'multipart/form-data; boundary=' + Bound;
    Result := HTTP.HTTPMethod('POST', URL);
    if Result then
      ResultData.LoadFromStream(HTTP.Document);
  finally
    HTTP.Free;
  end;
end;

Thank you.

Answer 1

Your code is close. You are only sending your file field but not your text fields. To do all three, try this instead:

function HttpPostFile(const URL, InputText1FieldName, InputText1, InputText2FieldName, InputText2, InputFileFieldName, InputFileName: string; InputFileData: TStream; ResultData: TStrings): Boolean; 
var 
  HTTP: THTTPSend; 
  Bound: string; 
begin 
  Bound := IntToHex(Random(MaxInt), 8) + '_Synapse_boundary'; 
  HTTP := THTTPSend.Create; 
  try 
    WriteStrToStream(HTTP.Document,
      '--' + Bound + CRLF +
      'Content-Disposition: form-data; name=' + AnsiQuotedStr(InputText1FieldName, '"') + CRLF +
      'Content-Type: text/plain' + CRLF +
      CRLF); 
    WriteStrToStream(HTTP.Document, InputText1); 
    WriteStrToStream(HTTP.Document,
      CRLF +
      '--' + Bound + CRLF +
      'Content-Disposition: form-data; name=' + AnsiQuotedStr(InputText2FieldName, '"') + CRLF +
      'Content-Type: text/plain' + CRLF +
      CRLF); 
    WriteStrToStream(HTTP.Document, InputText2); 
    WriteStrToStream(HTTP.Document,
      CRLF +
      '--' + Bound + CRLF +
      'Content-Disposition: form-data; name=' + AnsiQuotedStr(InputFileFieldName, '"') + ';' + CRLF + 
      #9'filename=' + AnsiQuotedStr(InputFileName, '"') + CRLF +
      'Content-Type: application/octet-string' + CRLF +
      CRLF); 
    HTTP.Document.CopyFrom(InputFileData, 0); 
    WriteStrToStream(HTTP.Document,
      CRLF +
      '--' + Bound + '--' + CRLF); 
    HTTP.MimeType := 'multipart/form-data; boundary=' + Bound; 
    Result := HTTP.HTTPMethod('POST', URL); 
    if Result then 
      ResultData.LoadFromStream(HTTP.Document); 
  finally 
    HTTP.Free; 
  end; 
end; 

If you switch to Indy, you can use its TIdMultipartFormDataStream class:

function HttpPostFile(const URL, InputText1FieldName, InputText1, InputText2FieldName, InputText2, InputFileFieldName, InputFileName: string; InputFileData: TStream; ResultData: TStrings): Boolean; 
var 
  HTTP: TIdHTTP; 
  Input: TIdMultipartFormDataStream;
  Output: TMemoryStream;
begin 
  Result := False;
  try
    Output := TMemoryStream.Create;
    try
      HTTP := TIdHTTP.Create; 
      try 
        Input := TIdMultipartFormDataStream.Create;
        try
          Input.AddFormField(InputText1FieldName, InputText1);
          Input.AddFormField(InputText2FieldName, InputText2);
          Input.AddFormField(InputFileFieldName, 'application/octet-stream', '', InputFileData, InputFileName);
          HTTP.Post(URL, Input, Output);
        finally
          Input.Free;
        end;
      finally
        HTTP.Free;
      end;
      Output.Position := 0;
      ResultData.LoadFromStream(Output);
      Result := True; 
    finally
      Output.Free;
    end;
  except
  end; 
end; 

Answer 2

I also use synapse in my projects. To be make my work simple and faster with Synapse, I wrote THTTPSendEx class, that gives fast speed of using and minimum of code and more features. Currently it's a beta version.

It's views like Indy.

Create THTTPSendEx class. Create methods OnBeginWork, OnWork, OnWorkEnd from it prototypes(see pas file), and assign it to created class. Thats all what you need, and just call GET, POST functions of the class.

I also implement multipart-fomdata for fast file posting in this format as TMultipartFormDataStream class. With it you can easy write files and fields.

Example of using:

var
 HTTP:THTTPSendEx;
 Data:TMultipartFormDataStream;
 sHTML:string; //Recived HTML code from web
begin
 HTTP:=THTTPSEndEx.Create;
 Data:=TMultipartFormDataStream.Create;
 try
  Data.AddFile('myFile','Path to the local file(No UNC paths)');
  Data.DataEnd;
  if HTTP.Post('URL HERE',Data,sHTML) then
  begin
  //Connection established
  //Check HTTP response
  if HTTP.IsSuccessfull then  //HTTP returns "200 OK" code.
  begin
    ShowMessage('File successfully posted to the server.');
  end;
  end else
  begin
   ShowMessage('Can not establish a connection to the server...'+#13+'Network is not avaliable or server socket does not exist.');
  end;
 finally
   FreeAndNil(HTTP);
   FreeAndNil(Data);
 end;
end;

You can see it at my web-site.

If you have any ideas for this, please write it's as a comment to project page.

Sorry for mistakes in english.

Answer 3

Good reading: http://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.2

Problem solved. I keep the question public in case anyone has the same question one day.