I have this code:
function VisitCookie(const name, value, domain, path: ustring;
secure, httponly, hasExpires: Boolean; const creation, lastAccess,
expires: TdateTime; Count, total: integer; out deleteCookie: Boolean)
: Boolean;
begin
RichEdit1.Lines.Add('cookie ' + inttostr(Count) + '/' + inttostr(total));
RichEdit1.Lines.Add('name ' + name);
RichEdit1.Lines.Add('value ' + value);
RichEdit1.Lines.Add('domain ' + domain);
RichEdit1.Lines.Add('path ' + path);
RichEdit1.Lines.Add('secure ' + BoolToStr(secure));
RichEdit1.Lines.Add('httponly ' + BoolToStr(httponly));
RichEdit1.Lines.Add('hasExpires ' + BoolToStr(hasExpires));
RichEdit1.Lines.Add('creation ' + DateToStr(creation));
RichEdit1.Lines.Add('lastAccess ' + DateToStr(lastAccess));
RichEdit1.Lines.Add('expires ' + DateToStr(expires));
RichEdit1.Lines.Add('------------------------');
Result := true;
end;
function GetCookies: Boolean;
begin
CookieManager := TCefCookieManagerRef.Global(nil);
CookieManager.VisitAllCookiesProc(VisitCookie);
end;
If I set Result := false in my function VisitCookie - I only get the value of the first cookie, that's all. I.e. pass through the cookies does not happen. But if I set Result := true - I got an access violation, but it works fine, until I have not so much cookies records in Chromium, for example 5-10 records. I have no idea why this happens.
The problem is that the visitor callback function of the VisitAllCookies method is executed in the context of a CEF worker thread, not in a context of the main thread hence you cannot access VCL controls from there. The VisitAllCookies method returns immediately and the callback function is then called asynchronously from the CEF worker thread.
There are many ways how to implement such cooperation. But it's not CEF specific. It's about how to pass (or collect) certain data from a worker thread callback and pass it back to the main thread. Optionally also about taking the callback under control in a synchronous way (to interrupt running enumeration).
Here is one untested example (maybe too overcomplicated). The principle remains, how to collect data from an uncontrolled thread callback function for the main thread (or take it under control in a synchronous way):
type
TCookie = record
Name: string;
Value: string;
Expires: TDateTime;
end;
TProcessCookieEvent = procedure(Sender: TObject; const Cookie: TCookie;
const IsLast: Boolean; var Delete: Boolean; var Cancel: Boolean) of object;
TCookieManager = class
private
FWndHandle: HWND;
FOnProcessCookie: TProcessCookieEvent;
protected
procedure WndProc(var Msg: TMessage); virtual;
public
constructor Create;
destructor Destroy; override;
procedure ProcessCookies(Timeout: UINT = 5000);
property OnProcessCookie: TProcessCookieEvent read FOnProcessCookie write FOnProcessCookie;
end;
implementation
const
PA_CANCEL = 1;
PA_DELETE = 2;
CM_PROCESSCOOKIE = WM_USER + 100;
type
PCookie = ^TCookie;
constructor TCookieManager.Create;
begin
inherited;
FWndHandle := AllocateHWnd(WndProc);
end;
destructor TCookieManager.Destroy;
begin
DeallocateHWnd(FWndHandle);
inherited;
end;
procedure TCookieManager.WndProc(var Msg: TMessage);
var
Delete: Boolean;
Cancel: Boolean;
IsLast: Boolean;
begin
if Msg.Msg = CM_PROCESSCOOKIE then
begin
Msg.Result := 0;
if Assigned(FOnProcessCookie) then
try
Delete := False;
Cancel := False;
IsLast := Boolean(Msg.wParam);
FOnProcessCookie(Self, PCookie(Msg.lParam)^, IsLast, Delete, Cancel);
if Delete then
Msg.Result := Msg.Result or PA_DELETE;
if Cancel then
Msg.Result := Msg.Result or PA_CANCEL;
except
Application.HandleException(Self);
end;
end
else
Msg.Result := DefWindowProc(FWndHandle, Msg.Msg, Msg.wParam, Msg.lParam);
end;
procedure TCookieManager.ProcessCookies(Timeout: UINT = 5000);
var
CookieManager: ICefCookieManager;
begin
CookieManager := TCefCookieManagerRef.Global(nil);
CookieManager.VisitAllCookiesProc(
{ this function will be called asynchronously from a CEF worker thread }
function(const Name, Value, Domain, Path: UString; Secure, HTTPOnly,
HasExpires: Boolean; const Creation, LastAccess, Expires: TDateTime;
Count, Total: Integer; out DeleteCookie: Boolean): Boolean
var
MsgRet: DWORD;
Cookie: TCookie;
IsLast: Boolean;
begin
{ initialize cancel of enumeration and no cookie deletion }
Result := False;
DeleteCookie := False;
{ fill the cookie structure }
Cookie.Name := string(Name);
Cookie.Value := string(Value);
Cookie.Expires := Expires;
{ determine if it's the last enumerated cookie }
IsLast := Count = Total-1;
{ yes, I'm doing what many would not do, but let me explain, this is not
SendMessage, that could get stuck forever when the message pump of the
receiver got stucked so I've let this thread responsive (SMTO_NORMAL),
let this call fail when the receiver is "hung" (SMTO_ABORTIFHUNG) and
let the function fail if the receiver is destroyed (SMTO_ERRORONEXIT)
and there is the timeout, in which the receiver needs to process this
message (if the message is not processed for some reason, enumerating
stops) }
if SendMessageTimeout(FWndHandle, CM_PROCESSCOOKIE, WPARAM(IsLast),
LPARAM(@Cookie), SMTO_NORMAL or SMTO_ABORTIFHUNG or SMTO_ERRORONEXIT,
Timeout, MsgRet) <> 0 then
begin
Result := MsgRet and PA_CANCEL <> PA_CANCEL;
DeleteCookie := MsgRet and PA_DELETE = PA_DELETE;
end;
{ else GetLastError and try to signal error by posting another message }
end;
);
end;
And a possible usage:
type
TForm1 = class(TForm)
Button1: TButton;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure Button1Click(Sender: TObject);
private
FCookieList: TList<TCookie>;
FCookieManager: TCookieManager;
procedure DoProcessCookie(Sender: TObject; const Cookie: TCookie;
const IsLast: Boolean; var Delete: Boolean; var Cancel: Boolean);
end;
implementation
procedure TForm1.FormCreate(Sender: TObject);
begin
FCookieList := TList<TCookie>.Create;
FCookieManager := TCookieManager.Create;
FCookieManager.OnProcessCookie := DoProcessCookie;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
FCookieManager.Free;
FCookieList.Free;
end;
procedure TForm1.DoProcessCookie(Sender: TObject; const Cookie: TCookie;
const IsLast: Boolean; var Delete: Boolean; var Cancel: Boolean);
begin
{ IsLast signals last enumerated cookie, Delete output parameter can delete
the currently enumerated cookie, and Cancel output parameter can stop the
enumeration }
FCookieList.Add(Cookie);
if IsLast then
ShowMessage('All cookies has been enumerated!');
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
FCookieList.Clear;
FCookieManager.ProcessCookies;
end;