(Delphi ActiveX) How to Access Parts of a multipart/related HTTP Response

Demonstrates how to access the parts of a multipart/related response. This example sends a ficticious multipart/related request, and handles a ficticious multipart/related response.

We send the following multipart/related request:

Content-Type: multipart/related; start-info="text/xml"; type="application/xop+xml"; boundary="----=_Part_0_1744155.1118953559416"
Content-Length: 3453
SOAPAction: "some-SOAP-action"

------=_Part_1_4558657.1118953559446
Content-Type: application/xop+xml; type="text/xml"; charset=utf-8

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <Detail xmlns="http://example.org/mtom/data">
      <image>
        <xop:Include xmlns:xop="http://www.w3.org/2004/08/xop/include" href="cid:5aeaa450-17f0-4484-b845-a8480c363444@example.org" />
      </image>
    </Detail>
  </soap:Body>
</soap:Envelope>

------=_Part_1_4558657.1118953559446
Content-Type: image/jpeg
Content-ID: <5aeaa450-17f0-4484-b845-a8480c363444@example.org>


... binary data ...

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

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
http: TChilkatHttp;
soapXml: TChilkatXml;
xmlBody: WideString;
req: TChilkatHttpRequest;
useTls: Integer;
resp: IChilkatHttpResponse;
mime: TChilkatMime;
part0: IChilkatMime;
subPartXmlBody: WideString;

begin
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

http := TChilkatHttp.Create(Self);

soapXml := TChilkatXml.Create(Self);

// Build the following SOAP XML

// <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
//   <soap:Body>
//     <Detail xmlns="http://example.org/mtom/data">
//       <image>
//         <xop:Include xmlns:xop="http://www.w3.org/2004/08/xop/include" href="cid:5aeaa450-17f0-4484-b845-a8480c363444@example.org" />
//       </image>
//     </Detail>
//   </soap:Body>
// </soap:Envelope>

soapXml.Tag := 'soap:Envelope';
soapXml.AddAttribute('xmlns:soap','http://schemas.xmlsoap.org/soap/envelope/');
soapXml.UpdateAttrAt('soap:Body|Detail',1,'xmlns','http://example.org/mtom/data');
soapXml.UpdateAttrAt('soap:Body|Detail|image|xop:Include',1,'xmlns:xop','http://www.w3.org/2004/08/xop/include');
soapXml.UpdateAttrAt('soap:Body|Detail|image|xop:Include',1,'href','cid:5aeaa450-17f0-4484-b845-a8480c363444@example.org');

soapXml.EmitXmlDecl := 0;
xmlBody := soapXml.GetXml();
Memo1.Lines.Add(xmlBody);

req := TChilkatHttpRequest.Create(Self);
req.HttpVerb := 'POST';
req.Path := '/something/someTarget';

req.ContentType := 'multipart/related; start-info="text/xml"; type="application/xop+xml"';
req.AddHeader('SOAPAction','some-SOAP-action');

success := req.AddStringForUpload2('','',xmlBody,'utf-8','application/xop+xml; type="text/xml"; charset=utf-8');

// The bytes will be sent as binary (not base64 encoded).
success := req.AddFileForUpload2('','qa_data/jpg/starfish.jpg','image/jpeg');

// The JPEG data is the 2nd sub-part, and therefore is at index 1 (the first sub-part is at index 0)
success := req.AddSubHeader(1,'Content-ID','<5aeaa450-17f0-4484-b845-a8480c363444@example.org>');

http.FollowRedirects := 1;

useTls := 1;
resp := http.SynchronousRequest('www.example.org',443,useTls,req.ControlInterface);
if (http.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

// Imagine the HTTP response is multipart related and is something like this:

// HTTP/1.1 200 OK
// Cache-Control: no-cache, no-store
// Pragma: no-cache
// Transfer-Encoding: chunked
// Content-Type: multipart/related; boundary=------------080001080500020607080905
// Expires: -1
// Server: Microsoft-IIS/10.0
// X-AspNet-Version: 4.0.30319
// X-Powered-By: ASP.NET
// Date: Wed, 19 Feb 2020 15:27:06 GMT
// 
// --------------080001080500020607080905
// Content-Type: application/xop+xml; charset=iso-8859-1
// Content-Id: RootPart
// Content-Transfer-Encoding: binary
// 
// <?xml version="1.0" encoding="iso-8859-1"?>
// <soapenv:Envelope xmlns:xcpt="...">
//   <soapenv:Header />
//   <soapenv:Body>
//     <xres:Transport profile="http://something.example.com/..." version="1.4">
//       <xres:TransportHeader>
// 	...
// 	...
//       </xres:TransportHeader>
//       <xres:TransportBody />
//     </xres:Transport>
//   </soapenv:Body>
// </soapenv:Envelope>
// --------------080001080500020607080905--

// To get the XML, load the full MIME of the response into a Chilkat MIME object.  Then get the body of the 1st sub-part.
mime := TChilkatMime.Create(Self);
mime.LoadMime(resp.FullMime);

// Your code might verify that the Content-Type is indeed multipart/related.
Memo1.Lines.Add(mime.ContentType);
Memo1.Lines.Add('num parts = ' + IntToStr(mime.NumParts));

// Assuming it is, and the number of sub-parts is > 0
if (mime.NumParts > 0) then
  begin
    part0 := mime.GetPart(0);
    // The Content-Type (in this ficticious example) should be "application/xop+xml"
    Memo1.Lines.Add('sub-part Content-Type: ' + part0.ContentType);
    // Now get the XML 
    subPartXmlBody := part0.GetBodyDecoded();
    Memo1.Lines.Add(subPartXmlBody);

  end;
end;