[英]Delphi 10.1 and CEF3 troubles with cookies
I have this code: 我有以下代码:
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. 如果我在函数VisitCookie
中将Result := false
设置为-我仅获得第一个cookie的值,仅此而已。 Ie pass through the cookies does not happen. 即通过cookie不会发生。 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. 但是,如果我将Result := true
设置Result := true
-我遇到了访问冲突,但工作正常,直到Chromium中没有那么多cookie记录,例如5-10条记录。 I have no idea why this happens. 我不知道为什么会这样。
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. 问题在于, VisitAllCookies方法的访客回调函数是在CEF 工作线程的上下文中执行的,而不是在主线程的上下文中执行的,因此您不能从那里访问VCL控件。 The VisitAllCookies method returns immediately and the callback function is then called asynchronously from the CEF worker thread. VisitAllCookies方法立即返回,然后从CEF 工作线程异步调用回调函数。
There are many ways how to implement such cooperation. 如何进行这种合作有很多方法。 But it's not CEF specific. 但这不是CEF特有的。 It's about how to pass (or collect) certain data from a worker thread callback and pass it back to the main thread. 它是关于如何从工作线程回调中传递(或收集)某些数据并将其传递回主线程的。 Optionally also about taking the callback under control in a synchronous way (to interrupt running enumeration). 也可以选择以同步方式控制回调(以中断正在运行的枚举)。
Here is one untested example (maybe too overcomplicated). 这是一个未经测试的示例(可能过于复杂)。 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): 原理仍然是,如何从主线程的不受控制的线程回调函数中收集数据(或以同步方式在控制之下):
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: 以及可能的用法:
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;
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