Delphi ActiveX

Building a multipart/form-data Request for HTTP Upload

See more HTTP Examples

Uploading files to a web server typically requires building a multipart/form-data request where the files are contained in the sub-parts of the MIME request.

Note: HTTP uploads require code on the server-side to receive the upload. For example, see Complete C# ASP.NET HTTP Upload Example

This example produces the following HTTP multipart/form-data request:

POST /something HTTP/1.1
Content-Type: multipart/form-data; boundary=------------070002080409050901090203
Host: domain
Content-Length: 546

--------------070002080409050901090203
Content-Disposition: form-data; name="fileA"; filename="fileA.txt"
Content-Type: text/plain

This is the contents of file A
--------------070002080409050901090203
Content-Disposition: form-data; name="fileB"; filename="fileB.txt"
Content-Type: text/plain

This is the contents of file B
--------------070002080409050901090203
Content-Disposition: form-data; name="fileC"; filename="fileC.txt"
Content-Type: text/plain

This is the contents of file C
--------------070002080409050901090203--

Delphi ActiveX

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
req: TChilkatHttpRequest;
requestMime: WideString;

begin
// This example demonstrates building a multipart/form-data request.

req := TChilkatHttpRequest.Create(Self);

// The ContentType, HttpVerb, and Path properties should
// always be explicitly set.
req.HttpVerb := 'POST';
req.Path := '/something';
req.ContentType := 'multipart/form-data';

// The contents and name of each file to be uploaded is provided
// by calling any of the following methods:
// AddBytesForUpload
// AddBytesForUpload2
// AddFileForUpload
// AddFileForUpload2
// AddStringForUpload
// AddStringForUpload2

// For this example, we'll provide the contents of the files to be uploaded
// directly as in-memory strings.
req.AddStringForUpload('fileA','fileA.txt','This is the contents of file A','utf-8');
req.AddStringForUpload('fileB','fileB.txt','This is the contents of file B','utf-8');
req.AddStringForUpload('fileC','fileC.txt','This is the contents of file C','utf-8');

// View the request that would be sent if HttpSReq was called:
requestMime := req.GenerateRequestText();
Memo1.Lines.Add(requestMime);

// A few important comments about the HTTP request that is generated:
// 
// 1) Chilkat automatically generates a random boundary string.   In 99.999% of cases, this should 
//    be sufficient.
// 2) The Content-Length header is automatically generated based on the actual length of the MIME message
//    that follows the intial (topmost) MIME header.
// 3) The HOST header will automatically get filled in with the actual domain when HttpSReq
//    is called
end;