(Delphi DLL) HTTP Request Boundary Property

Explains and demonstrates the HTTP request Boundary property. For multipart HTTP requests, Chilkat auto-generates a boundary string when the Boundary property is left unset (or empty). For example:

POST /something HTTP/1.1
Content-Type: multipart/form-data; boundary=------------090207000006060206010508
Host: domain
Content-Length: 378

--------------090207000006060206010508
Content-Disposition: form-data; name="fileA"; filename="fileA.txt"
Content-Type: text/plain

This is the contents of file A
--------------090207000006060206010508
Content-Disposition: form-data; name="fileB"; filename="fileB.txt"
Content-Type: text/plain

This is the contents of file B
--------------090207000006060206010508--

POST /something HTTP/1.1
Content-Type: multipart/form-data; boundary=ABC123HELLOWORLD
Host: domain
Content-Length: 318

--ABC123HELLOWORLD
Content-Disposition: form-data; name="fileA"; filename="fileA.txt"
Content-Type: text/plain

This is the contents of file A
--ABC123HELLOWORLD
Content-Disposition: form-data; name="fileB"; filename="fileB.txt"
Content-Type: text/plain

This is the contents of file B
--ABC123HELLOWORLD--

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, HttpRequest;

...

procedure TForm1.Button1Click(Sender: TObject);
var
req: HCkHttpRequest;

begin
req := CkHttpRequest_Create();

CkHttpRequest_putHttpVerb(req,'POST');
CkHttpRequest_putPath(req,'/something');
CkHttpRequest_putContentType(req,'multipart/form-data');

CkHttpRequest_AddStringForUpload(req,'fileA','fileA.txt','This is the contents of file A','utf-8');
CkHttpRequest_AddStringForUpload(req,'fileB','fileB.txt','This is the contents of file B','utf-8');

// When the Boundary property is empty (has not yet been set)
// Chilkat auto-generates a random boundary for the request.
// This should almost always be sufficient.
// For example, one can see the generated boundary here:
Memo1.Lines.Add(CkHttpRequest__generateRequestText(req));

// If the Boundary property is set to a specific string, then the
// request will use it:
CkHttpRequest_putBoundary(req,'ABC123HELLOWORLD');
Memo1.Lines.Add(CkHttpRequest__generateRequestText(req));

CkHttpRequest_Dispose(req);

end;