Delphi ActiveX

Fetch Web Pages from Local Cache

See more HTTP Examples

Demonstrates how to keep a local cache to avoid re-fetching web pages. 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
http: TChilkatHttp;
html: WideString;

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

http := TChilkatHttp.Create(Self);

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

// up to 256 sub-directories under the cache root will be created as needed to hold cached GET's.
http.NumCacheLevels := 1;

// Tell the http object to fetch from the cache if possible.
http.FetchFromCache := 1;

// Also tell the http object to update the cache with newly fetched pages.
http.UpdateCache := 1;

// This HTTP GET should result in a cache file getting created.
html := http.QuickGetStr('https://www.google.com/');
if (http.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

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

// Fetching again will cause the page to be delivered from our local cache.
html := http.QuickGetStr('https://www.google.com/');
if (http.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

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