(Delphi ActiveX) Initialize an HTTP Request from a URL

Demonstrates how to initialize an HTTP request object from a URL.

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
req: TChilkatHttpRequest;
i: Integer;
numParams: Integer;

begin
req := TChilkatHttpRequest.Create(Self);

// Loads the HTTP request object from a URL
req.SetFromUrl('https://www.youtube.com/watch?v=fAZdTchQePc&t=45s');

// The verb will be "GET"
Memo1.Lines.Add('verb = ' + req.HttpVerb);
// The path will be "/watch"
Memo1.Lines.Add('path = ' + req.Path);

// The output of this loop will be
// 0) v: fAZdTchQePc
// 1) t: 45s

numParams := req.NumParams;
for i := 0 to numParams - 1 do
  begin
    Memo1.Lines.Add(IntToStr(i) + ') ' + req.GetParamName(i) + ': ' + req.GetParamValue(i));
  end;

// View the request that would be sent if SynchronousRequest is called.
// The HTTP request will be a GET that looks like this:
// 
//     GET /watch?v=fAZdTchQePc&t=45s HTTP/1.1
//     Host: domain
// 
// Note: The HOST header will automatically get filled in with the actual domain when SynchronousRequest is called.

Memo1.Lines.Add(req.GenerateRequestText());

// We can add additional params
req.AddParam('artist','Richard Bona');
req.AddParam('musicType','Jazz');
req.AddParam('festival','Estival Jazz Lugano');
req.AddParam('year','2008');

// Now examine the request that would be sent
// 
//     GET /watch?v=fAZdTchQePc&t=45s&artist=Richard%20Bona&musicType=Jazz&festival=Estival%20Jazz%20Lugano&year=2008 HTTP/1.1
//     Host: domain
// 
Memo1.Lines.Add(req.GenerateRequestText());

// We can remove a parameter:
req.RemoveParam('t');
Memo1.Lines.Add(req.GenerateRequestText());

// What happens if we change the request from a GET to a POST?
req.HttpVerb := 'POST';
// The request will now look like this:
// 
//    POST /watch HTTP/1.1
//    Host: domain
//    Content-Length: 93
//    
//    v=fAZdTchQePc&artist=Richard%20Bona&musicType=Jazz&festival=Estival%20Jazz%20Lugano&year=2008
// 
Memo1.Lines.Add(req.GenerateRequestText());

// What happens if we make it a multipart/form-data?
req.ContentType := 'multipart/form-data';
// Now the POST looks like this:
//    
//    POST /watch HTTP/1.1
//    Content-Type: multipart/form-data; boundary=------------020906020106050705030807
//    Host: domain
//    Content-Length: 545
//    
//    --------------020906020106050705030807
//    Content-Disposition: form-data; name="v"
//    
//    fAZdTchQePc
//    --------------020906020106050705030807
//    Content-Disposition: form-data; name="artist"
//    
//    Richard Bona
//    --------------020906020106050705030807
//    Content-Disposition: form-data; name="musicType"
//    
//    Jazz
//    --------------020906020106050705030807
//    Content-Disposition: form-data; name="festival"
//    
//    Estival Jazz Lugano
//    --------------020906020106050705030807
//    Content-Disposition: form-data; name="year"
//    
//    2008
//    --------------020906020106050705030807--

Memo1.Lines.Add(req.GenerateRequestText());
end;