我在Delphi 2007中使用最新的Delphi Chromium Embedded包装器（使用libcef 3.1750.1738，我相信由DCEF3创建者编译）实现了GetResourceHandler调用。我将我的处理程序基于magpcss网站上发布的一些python代码（有一些更改）。
一切都运作良好，除了一些事情。首先，“blob：”网址不起作用，我正在摸索如何让他们去。我一般都不了解它们，所以这是问题的一部分。
其次，使用我的资源处理程序时会弹出一些跨源的东西，否则就会弹出。这是我对https://maps.google.com/的测试。我明白了：
GET blob:https%3A//map.google.com/93e08d0a-b8b3-4c60-8a82-71d424b0893c 404 (Not Found) rs=ACT90oHHUBc59MzTbg1AU48l7w-F8f1yuA:1107
GET blob:https%3A//map.google.com/4c89a387-5958-4c19-ae9c-0640007db009 404 (Not Found) rs=ACT90oHHUBc59MzTbg1AU48l7w-F8f1yuA:1107
GET blob:https%3A//map.google.com/bd839949-a77b-43a1-9f47-1cb841f858a9 404 (Not Found) /maps/_/js/k=maps.m.en.oD0-LnUwxmc.O/m=sy437,sy444,sy446,sy486,sy494,wrc,sy438,sy436,vw,sy139,sy220…:134
XMLHttpRequest cannot load https://mt0.google.com/vt?pb=!1m8!4m7!2u15!5m2!1x450831026!2x3361961734!6m2!1x451029165!2x3362284457!2m1!1e0!3m1!5e1105!4e5!18m1!1b1. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'https://map.google.com' is therefore not allowed access. /maps/@45.0930104,-93.28442,15z:1
XMLHttpRequest cannot load https://mt0.google.com/vt/pb=!1m8!3m7!1m2!1u2020096!2u3014144!2m2!1u1024!2u768!3i15!2m3!1e0!2sm!3i290!3m2!2sen!5e1105!4e4!11m2!1e2!2b1!20m1!1b1. No 'Access-Control-Allow- Origin' header is present on the requested resource. Origin 'https://map.google.com' is therefore not allowed access. /maps/@45.0930104,-93.28442,15z:1
然而，当省略我的资源处理程序并在没有它的情况下使用CEF时，这些问题都不会发生。我发现我可以通过禁用Web安全来解决CORS问题。这似乎不太理想，而且在没有我的资源处理程序的情况下使用CEF时也不需要。
这是我的资源处理程序代码：
unit WebInterceptHandler;
interface
uses
ceflib, Classes;
type
TWebInterceptHandler = class(TCefResourceHandlerOwn)
protected
FDataStream: TMemoryStream;
FResponseHeadersReadyCallback: ICefCallback;
FOffsetRead: NativeUInt;
FResponse: ICefResponse;
function ProcessRequest(const Request: ICefRequest;
const Callback: ICefCallback): Boolean; override;
procedure GetResponseHeaders(const Response: ICefResponse;
out ResponseLength: Int64; out RedirectUrl: ustring); override;
function ReadResponse(const DataOut: Pointer; BytesToRead: Integer;
var BytesRead: Integer; const Callback: ICefCallback): Boolean; override;
public
constructor Create(const Browser: ICefBrowser; const Frame: ICefFrame;
const SchemeName: ustring; const Request: ICefRequest); override;
destructor Destroy; override;
end;
implementation
uses windows, sysutils;
type
TWebInterceptHandlerClient = class(TCefUrlRequestClientOwn)
private
FResourceHandler: TWebInterceptHandler;
protected
procedure OnDownloadData(const Request: ICefUrlRequest; Data: Pointer;
DataLength: NativeUInt); override;
procedure OnRequestComplete(const Request: ICefUrlRequest); override;
end;
{ TWebInterceptHandlerClient }
procedure TWebInterceptHandlerClient.OnDownloadData(const Request: ICefUrlRequest;
Data: Pointer; DataLength: NativeUInt);
begin
inherited;
FResourceHandler.FDataStream.Write(Data^, DataLength);
//OutputDebugStringW(PWideChar(Request.GetRequest.Url));
end;
procedure TWebInterceptHandlerClient.OnRequestComplete(const Request: ICefUrlRequest);
begin
inherited;
FResourceHandler.FResponse := Request.GetResponse;
if FResourceHandler.FResponseHeadersReadyCallback <> nil then
FResourceHandler.FResponseHeadersReadyCallback.Cont;
end;
{ TWebInterceptHandler }
constructor TWebInterceptHandler.Create(const Browser: ICefBrowser;
const Frame: ICefFrame; const SchemeName: ustring;
const Request: ICefRequest);
begin
inherited;
FDataStream := TMemoryStream.Create;
end;
//function HTTPDecode(const AStr: ustring): rbstring;
//var
// Sp, Rp, Cp: PAnsiChar;
// src: rbstring;
//begin
// src := rbstring(AStr);
// SetLength(Result, Length(src));
// Sp := PAnsiChar(src);
// Rp := PAnsiChar(Result);
// while Sp^ <> #0 do
// begin
// case Sp^ of
// '+': Rp^ := ' ';
// '%': begin
// Inc(Sp);
// if Sp^ = '%' then
// Rp^ := '%'
// else
// begin
// Cp := Sp;
// Inc(Sp);
// if (Cp^ <> #0) and (Sp^ <> #0) then
// Rp^ := AnsiChar(StrToInt('$' + Char(Cp^) + Char(Sp^)))
// else
// begin
// Result := '';
// Exit;
// end;
// end;
// end;
// else
// Rp^ := Sp^;
// end;
// Inc(Rp);
// Inc(Sp);
// end;
// SetLength(Result, Rp - PAnsiChar(Result));
//end;
destructor TWebInterceptHandler.Destroy;
begin
FDataStream.Free;
inherited;
end;
function TWebInterceptHandler.ProcessRequest(const Request: ICefRequest;
const Callback: ICefCallback): Boolean;
var
wrc: TWebInterceptHandlerClient;
// url: ustring;
// i: Integer;
// headerMap: ICefStringMultimap;
begin
//headerMap := TCefStringMultimapOwn.Create;
//OutputDebugStringW(PWideChar(Request.Url));
//Request.GetHeaderMap(headerMap);
//if headerMap.Size <> 0 then
// for i := 0 to headerMap.Size - 1 do
// OutputDebugStringW(PWideChar(headerMap.Key[i] + ': ' + headerMap.Value[i]));
//if Pos('blob:', WideLowerCase(Request.Url)) = 1 then
// request.Url := HTTPDecode(Copy(Request.Url, 1, Length(Request.Url) - Length('blob:')));
FOffsetRead := 0;
FResponseHeadersReadyCallback := Callback;
wrc := TWebInterceptHandlerClient.Create;
wrc.FResourceHandler := Self;
TCefUrlRequestRef.New(request, wrc);
Result := True;
end;
procedure TWebInterceptHandler.GetResponseHeaders(const Response: ICefResponse;
out ResponseLength: Int64; out RedirectUrl: ustring);
var
headerMap: ICefStringMultimap;
begin
headerMap := TCefStringMultimapOwn.Create;
Response.Status := FResponse.Status;
Response.StatusText := FResponse.StatusText;
Response.MimeType := FResponse.MimeType;
FResponse.GetHeaderMap(headerMap);
if headerMap.Size <> 0 then
FResponse.SetHeaderMap(headerMap);
ResponseLength := FDataStream.Size;
end;
function TWebInterceptHandler.ReadResponse(const DataOut: Pointer; BytesToRead:
Integer; var BytesRead: Integer; const Callback: ICefCallback): Boolean;
begin
if FOffsetRead < FDataStream.Size then
begin
BytesRead := BytesToRead;
Move(Pointer(NativeUInt(FDataStream.Memory) + FOffsetRead)^, DataOut^,
BytesRead);
Inc(FOffsetRead, BytesRead);
Result := True;
end
else
Result := False;
end;
end.
我从测试应用中调用的是：
object MainForm: TMainForm
Left = 0
Top = 0
Caption = 'MainForm'
ClientHeight = 716
ClientWidth = 752
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
OnCreate = FormCreate
PixelsPerInch = 96
TextHeight = 13
object URLBox: TEdit
Left = 0
Top = 0
Width = 752
Height = 21
Align = alTop
TabOrder = 0
Text = 'https://map.google.com/'
OnKeyPress = URLBoxKeyPress
end
object Panel1: TPanel
Left = 0
Top = 21
Width = 752
Height = 41
Align = alTop
BevelOuter = bvNone
TabOrder = 1
ExplicitLeft = 296
ExplicitTop = 360
ExplicitWidth = 185
object Button1: TButton
Left = 8
Top = 8
Width = 120
Height = 25
Caption = 'Show Dev Tools'
TabOrder = 0
OnClick = Button1Click
end
object UseResourceHandlerBox: TCheckBox
Left = 152
Top = 12
Width = 233
Height = 17
Caption = 'Use Resource Handler'
TabOrder = 1
end
end
end
unit MainUnit;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, cefgui, ceflib, cefvcl, StdCtrls, ExtCtrls;
type
TMainForm = class(TForm)
URLBox: TEdit;
Panel1: TPanel;
Button1: TButton;
UseResourceHandlerBox: TCheckBox;
procedure FormCreate(Sender: TObject);
procedure URLBoxKeyPress(Sender: TObject; var Key: Char);
procedure Button1Click(Sender: TObject);
private
browser: TChromium;
procedure BrowserGetResourceHandler(Sender: TObject;
const Browser: ICefBrowser; const Frame: ICefFrame;
const Request: ICefRequest; out Result: ICefResourceHandler);
end;
var
MainForm: TMainForm;
implementation
{$R *.dfm}
uses
WebInterceptHandler;
procedure TMainForm.URLBoxKeyPress(Sender: TObject; var Key: Char);
begin
if Key = #13 then
begin
if UseResourceHandlerBox.Checked then
browser.OnGetResourceHandler := BrowserGetResourceHandler
else
browser.OnGetResourceHandler := nil;
browser.Load(URLBox.Text);
end;
end;
procedure TMainForm.Button1Click(Sender: TObject);
begin
browser.ShowDevTools;
end;
procedure TMainForm.FormCreate(Sender: TObject);
begin
browser := TChromium.Create(Self);
browser.Align := alClient;
browser.Parent := Self;
//browser.Options.WebSecurity := STATE_DISABLED;
end;
procedure TMainForm.BrowserGetResourceHandler(Sender: TObject; const Browser:
ICefBrowser; const Frame: ICefFrame; const Request: ICefRequest;
out Result: ICefResourceHandler);
begin
Result := TWebInterceptHandler.Create(Browser, Frame, 'webintercept', Request);
end;
end.
program DCEF3WebIntercept;
uses
ceflib,
Forms,
MainUnit in 'MainUnit.pas' {MainForm},
WebInterceptHandler in 'WebInterceptHandler.pas';
{$R *.res}
begin
CefCache := 'cache';
CefSingleProcess := False;
if not CefLoadLibDefault then
Exit;
Application.Initialize;
Application.MainFormOnTaskbar := True;
Application.CreateForm(TMainForm, MainForm);
Application.Run;
end.
除了对这些问题的任何帮助外，欢迎任何改进此代码的建议。
此外，如果有人想知道，我打算稍后修改此代码，以便我可以更改响应。现在它只是GetResourceHandler的概念验证。
答案 0 :(得分：2)
blob网址是一个特殊的网址，指的是您的浏览器当前在内存中为当前网页提供的数据。在我看来，在BrowserGetResourceHandler（）中你应该检测url是否以＆＃34; blob开头：＆＃34;并在这种情况下返回NULL并让Chromium处理内部提取该URL。如果仍然不起作用，可能是CEF的限制，应报告错误。
CORS安全问题似乎是由请求/响应中缺少标头引起的。做一些调试：