pascal-Pascal fpCEF3：在Free Pascal中嵌入Chromium的强大框架

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摘要： Pascal fpCEF3：在Free Pascal中嵌入Chromium的强大框架项目概述 fpCEF3是一个基于Free Pascal的Chromium Embedded F...

Pascal fpCEF3：在Free Pascal中嵌入Chromium的强大框架

项目概述

fpCEF3是一个基于Free Pascal的Chromium Embedded Framework（CEF）封装库，它允许Pascal开发者在自己的应用程序中嵌入完整的Chromium浏览器引擎。该项目由开发者dliw创建并维护，为Pascal社区提供了一个强大而现代的Web集成解决方案。

核心特性

1. 完整的CEF功能封装

fpCEF3封装了CEF3的主要功能，包括： - 完整的浏览器控件支持 - JavaScript与Pascal代码双向通信 - Cookie管理 - 开发者工具集成 - 多进程架构支持

2. 跨平台兼容性

支持Windows、Linux和macOS
与Lazarus IDE完美集成
兼容多种Free Pascal编译器版本

3. 简化的API设计

提供直观的Pascal接口
减少CEF原生API的复杂性
包含丰富的示例代码

安装与配置

系统要求

Free Pascal 3.0.0或更高版本
Lazarus IDE（推荐）
CEF3二进制文件

安装步骤

克隆项目仓库：

text

git clone https://github.com/dliw/fpCEF3.git

下载CEF二进制文件：

从CEF官方网站下载对应平台的CEF二进制包
将文件解压到项目目录中

配置Lazarus：

将fpCEF3目录添加到Lazarus的库路径
在项目选项中包含必要的单元文件

基础使用示例

示例1：创建简单浏览器窗口

text

program SimpleBrowser;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Interfaces,
  Forms,
  uSimpleBrowser;

{$R *.res}

begin
  RequireDerivedFormResource := True;
  Application.Initialize;
  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.

text

unit uSimpleBrowser;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, Forms, Controls, Graphics, Dialogs,
  cef3types, cef3api, cef3lib, cef3intf, cef3own;

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    FBrowser: ICefBrowser;
    FClient: TCefClientOwn;
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

procedure TForm1.FormCreate(Sender: TObject);
var
  WindowInfo: TCefWindowInfo;
  Settings: TCefSettings;
  BrowserSettings: TCefBrowserSettings;
  Url: ustring;
begin
  // 初始化CEF
  CefLoadLibrary;
  CefInitialize(@Settings, nil, nil);

  // 创建浏览器窗口
  FillChar(WindowInfo, SizeOf(WindowInfo), 0);
  WindowInfo.style := WS_VISIBLE or WS_CHILD or WS_CLIPCHILDREN or WS_CLIPSIBLINGS or WS_TABSTOP;
  WindowInfo.parent_window := Handle;
  WindowInfo.x := 0;
  WindowInfo.y := 0;
  WindowInfo.width := ClientWidth;
  WindowInfo.height := ClientHeight;

  FillChar(BrowserSettings, SizeOf(BrowserSettings), 0);
  BrowserSettings.size := SizeOf(BrowserSettings);

  Url := 'https://www.example.com';

  // 创建浏览器实例
  FBrowser := CefBrowserHostCreateBrowserSync(@WindowInfo, FClient, @Url, @BrowserSettings, nil);
end;

end.

示例2：JavaScript与Pascal交互

text

unit uJSInteraction;

interface

uses
  Classes, SysUtils, cef3intf, cef3types, cef3api;

type
  TCustomRenderProcessHandler = class(TCefRenderProcessHandlerOwn)
  protected
    function OnProcessMessageReceived(const browser: ICefBrowser;
      sourceProcess: TCefProcessId; const message: ICefProcessMessage): Boolean; override;
  end;

  TCustomBrowser = class
  private
    FBrowser: ICefBrowser;
    // 处理来自JavaScript的消息
    procedure HandleJSMessage(const message: ICefProcessMessage);
  public
    procedure ExecuteJavaScript(const code: ustring);
    procedure SendMessageToJS(const name: ustring; const args: array of const);
  end;

implementation

procedure TCustomBrowser.ExecuteJavaScript(const code: ustring);
var
  Frame: ICefFrame;
begin
  if Assigned(FBrowser) then
  begin
    Frame := FBrowser.MainFrame;
    if Assigned(Frame) then
      Frame.ExecuteJavaScript(code, 'about:blank', 0);
  end;
end;

procedure TCustomBrowser.SendMessageToJS(const name: ustring; const args: array of const);
var
  Message: ICefProcessMessage;
  List: ICefListValue;
  i: Integer;
begin
  Message := TCefProcessMessageRef.New(name);
  List := Message.ArgumentList;

  for i := Low(args) to High(args) do
  begin
    case args[i].VType of
      vtInteger: List.SetInt(i - Low(args), args[i].VInteger);
      vtBoolean: List.SetBool(i - Low(args), args[i].VBoolean);
      vtString: List.SetString(i - Low(args), ustring(args[i].VString^));
      vtAnsiString: List.SetString(i - Low(args), ustring(AnsiString(args[i].VAnsiString)));
      vtUnicodeString: List.SetString(i - Low(args), ustring(UnicodeString(args[i].VUnicodeString)));
    end;
  end;

  FBrowser.SendProcessMessage(PID_RENDERER, Message);
end;

procedure TCustomBrowser.HandleJSMessage(const message: ICefProcessMessage);
var
  MessageName: ustring;
begin
  MessageName := message.Name;

  if MessageName = 'buttonClicked' then
  begin
    // 处理按钮点击事件
    ShowMessage('按钮被点击了！');
  end
  else if MessageName = 'formSubmitted' then
  begin
    // 处理表单提交
    // 可以从message.ArgumentList中获取数据
  end;
end;

示例3：自定义资源处理

text

unit uResourceHandler;

interface

uses
  Classes, SysUtils, cef3intf, cef3types, cef3api;

type
  TCustomResourceHandler = class(TCefResourceHandlerOwn)
  private
    FStream: TMemoryStream;
    FStatus: Integer;
    FStatusText: ustring;
    FMimeType: ustring;
  protected
    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

constructor TCustomResourceHandler.Create(const browser: ICefBrowser;
  const frame: ICefFrame; const schemeName: ustring; const request: ICefRequest);
begin
  inherited;
  FStream := TMemoryStream.Create;
end;

destructor TCustomResourceHandler.Destroy;
begin
  FStream.Free;
  inherited;
end;

function TCustomResourceHandler.ProcessRequest(const request: ICefRequest;
  const callback: ICefCallback): Boolean;
var
  Url: ustring;
  HtmlContent: string;
begin
  Result := True;
  Url := request.Url;

  // 根据URL生成自定义内容
  if Pos('custom://app/dashboard', Url) > 0 then
  begin
    HtmlContent := '<html><head><title>仪表板</title></head>' +
                   '<body><h1>欢迎使用自定义应用</h1>' +
                   '<p>这是通过fpCEF3提供的自定义内容</p></body></html>';

    FStream.WriteBuffer(Pointer(HtmlContent)^, Length(HtmlContent));
    FStream.Position := 0;

    FStatus := 200;
    FStatusText := 'OK';
    FMimeType := 'text/html';
  end
  else
  begin
    FStatus := 404;
    FStatusText := 'Not Found';
    FMimeType := 'text/plain';
  end;

  callback.Cont;
end;

procedure TCustomResourceHandler.GetResponseHeaders(const response: ICefResponse;
  out responseLength: Int64; out redirectUrl: ustring);
begin
  response.Status := FStatus;
  response.StatusText := FStatusText;
  response.MimeType := FMimeType;
  responseLength := FStream.Size;
end;

function TCustomResourceHandler.ReadResponse(const dataOut: Pointer;
  bytesToRead: Integer; var bytesRead: Integer; const callback: ICefCallback): Boolean;
begin
  bytesRead := FStream.Read(dataOut^, bytesToRead);
  Result := bytesRead > 0;
end;