(Delphi DLL) Fetch Web Pages from Local Cache

Demonstrates how to keep a local cache to avoid re-fetching web pages.

Note: This example requires Chilkat v9.5.0.91 or later.

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, Http;

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: HCkHttp;
html: PWideChar;

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

http := CkHttp_Create();

// Define a cache directory and set the number of levels based on the anticipated size of the cache.
CkHttp_AddCacheRoot(http,'c:/AAWorkarea/httpCache/');

// up to 256 sub-directories under the cache root will be created as needed to hold cached GET's.
CkHttp_putNumCacheLevels(http,1);

// Tell the http object to fetch from the cache if possible.
CkHttp_putFetchFromCache(http,True);

// Also tell the http object to update the cache with newly fetched pages.
CkHttp_putUpdateCache(http,True);

// This HTTP GET should result in a cache file getting created.
html := CkHttp__quickGetStr(http,'https://www.google.com/');
if (CkHttp_getLastMethodSuccess(http) = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

// The 1st GET was not from cache:
Memo1.Lines.Add('Fetched from cache: ' + IntToStr(Ord(CkHttp_getLastFromCache(http))));

// Fetching again will cause the page to be delivered from our local cache.
html := CkHttp__quickGetStr(http,'https://www.google.com/');
if (CkHttp_getLastMethodSuccess(http) = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

// The 2nd GET is from cache:
Memo1.Lines.Add('Fetched from cache: ' + IntToStr(Ord(CkHttp_getLastFromCache(http))));

CkHttp_Dispose(http);

end;