实现软件自动升级

  原理简单，在FTP上维护一个Update.ini文件，里面记录着要更新文件的版本号，本地也有一个Update.ini文件，每次启动更新程序时，先从FTP上下载Update.ini文件到本地名字为Update_new.ini，然后比较这两个文件，如果新的版本号大于旧的，或者新的文件在就ini中没有，这些就表示要更新的文件，然后逐一下载。

    本程序名字为AutoUpdate，你生成这个exe，然后和主程序一起打包，创建桌面快捷方式时，指向AutoUpdate，而不是主程序。

    在本地还有一个ini文件，比如叫ftp.ini吧，里面内容是

[coninfo]
main=Project1.exe
param={app}sayyes.pj2 -y bde.txt

main=Project1.exe：是主程序名称，和升级程序在同一目录

param={app}sayyes.pj2 -y bde.txt：这是命令行参数，app为当前路径，在程序中替换掉，传递给主程序（如果需要的话）

update.ini的内容格式如下

[root]
办事处查询.txt=20100519
[dbcard]
sayyes.pj2=20100519
FTP用户密码.txt=20100519

[root]代表根目录，后面的[dbcard]代表子目录，依次类推

unit Main;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, IdHTTP, IdBaseComponent, IdComponent, IdTCPConnection,
  IdTCPClient, IdFTP, ComCtrls, ExtCtrls,IniFiles,ShellAPI, jpeg;

type
  TfrmMain = class(TForm)
    IdFTP1: TIdFTP;
    IdHTTP1: TIdHTTP;
    ProgressBar1: TProgressBar;
    GroupBox1: TGroupBox;
    ld_host: TLabeledEdit;
    ld_username: TLabeledEdit;
    ld_psw: TLabeledEdit;
    ld_port: TLabeledEdit;
    Label1: TLabel;
    cb_mode: TComboBox;
    ProgressBar2: TProgressBar;
    Label3: TLabel;
    list_file: TListView;
    Label4: TLabel;
    procedure IdFTP1Work(Sender: TObject; AWorkMode: TWorkMode;
      const AWorkCount: Integer);
    procedure IdFTP1WorkEnd(Sender: TObject; AWorkMode: TWorkMode);
    procedure FormCreate(Sender: TObject);  private
    { Private declarations }
    FSize:Integer;
    FPath: string;
    FExePath: string;
    FInitPath: string;
    FIniFile:TIniFile;
    FHandle:HWND;
    FMainExe:string;
    FParam: string;

    procedure CheckUpdateList;
    function ConnectFTP:Boolean;
    procedure DownLoadFile;
    procedure LoadIni;
    procedure SaveIni;
  public
    { Public declarations }
  end;

var
  frmMain: TfrmMain;

implementation
uses
  Flash;
{$R *.dfm}
//下载进度
procedure TfrmMain.IdFTP1Work(Sender: TObject; AWorkMode: TWorkMode;
  const AWorkCount: Integer);
begin
  ProgressBar1.Position := AWorkCount;
  Application.ProcessMessages;
end;

procedure TfrmMain.IdFTP1WorkEnd(Sender: TObject; AWorkMode: TWorkMode);
begin
  ProgressBar1.Position := 0;
  ProgressBar2.StepBy(1);
end;

procedure TfrmMain.FormCreate(Sender: TObject);
var
  frm: TfrmFlash;
begin
  Self.Visible := False;
  //闪屏，可以不加
  frm := TfrmFlash.Create(nil);
  frm.Show;
  Application.ProcessMessages;
  FExePath := ExtractFilePath(Application.ExeName);
  FIniFile := TIniFile.Create(FExePath+'ftp.ini');
  //加载ini信息，就是主机和端口之类的信息
  LoadIni;
  try
    ConnectFTP;
    CheckUpdateList;
    Self.Visible := True;
    Application.ProcessMessages;
    DownLoadFile;
  finally
    
    FreeAndNil(frm);
    IdFTP1.Quit;
    FParam := StringReplace(FParam,'{app}',FExePath,[rfReplaceAll]);
//更新完毕后，启动主程序，并传入命令行参数
    ShellExecute(Handle,'open',PChar(FExePath+FMainExe),PChar(FParam),nil,SW_NORMAL);
    Application.Terminate;
  end;
end;

//检查更新列表
procedure TfrmMain.CheckUpdateList;
var
  oldFile,newFile:TStringList;
  i,ver,index:Integer;
  itemstr,itempath: string;
  item:TListItem;
begin
  oldFile := TStringList.Create;
  newFile := TStringList.Create;
  try
    list_file.Clear;
    //先下载服务器上的update.ini文件，存到本地update_new.ini
    IdFTP1.Get('update.ini',FExePath+'update_new.ini',True);
    if FileExists(FExePath + 'update.ini') = False then Exit;
    oldFile.LoadFromFile(FExePath + 'update.ini');
    newFile.LoadFromFile(FExePath + 'update_new.ini');
    itempath := '';
    //下面开始比较两个list，如果newFile的版本号大于oldFile的版本号或者oldFile中没有的都表示要更新的
    for i := 0 to newFile.Count - 1 do
    begin
      itemstr := newFile.Strings[i];
      if itemstr = '' then Continue;
      if itemstr[1] = '[' then
      begin
        itempath := Copy(itemstr,2,Length(itemstr)-2);
        //如果是根目录
        if itempath = 'root' then
          itempath := '/';
        Continue;
      end;
      itemstr := newFile.Names[i];
      index := oldFile.IndexOfName(itemstr);
      if index = - 1 then
      begin
        item := list_file.Items.Add;
        item.Caption := itemstr;
        item.SubItems.Add(itempath)
      end
      else
      begin
        ver := StrToIntDef(newFile.Values[itemstr],0);
        if ver > StrToIntDef(oldFile.Values[itemstr],0) then
        begin
          item := list_file.Items.Add;
          item.Caption := itemstr;
          item.SubItems.Add(itempath);
        end;
      end;
    end;
    if list_file.Items.Count = 0 then Application.Terminate;
  finally
    oldFile.Free;
    newFile.Free;
  end;
end;

function TfrmMain.ConnectFTP: Boolean;
begin
  Result := False;
  try
  IdFTP1.Host := ld_host.Text;
  IdFTP1.Port := StrToIntDef(ld_port.Text,21);
  IdFTP1.Username := ld_username.Text;
  IdFTP1.Password := ld_psw.Text;
  IdFTP1.Connect;
  IdFTP1.Passive := cb_mode.ItemIndex = 1;
  FInitPath := IdFTP1.RetrieveCurrentDir;
  Result := IdFTP1.Connected;
  except
    Result := False;
  end;
end;

//下载文件更新
procedure TfrmMain.DownLoadFile;
var
  i:Integer;
  path:string;
  s1,s2:String;
begin
  ProgressBar2.Max := list_file.Items.Count;
  ProgressBar2.Position := 0;
  FIniFile.EraseSection('error');
  for i := 0 to list_file.Items.Count - 1 do
  begin
    Label4.Caption := '正在下载 '+list_file.Items[i].Caption;
    Application.ProcessMessages;
    IdFTP1.ChangeDir(FInitPath);
    path := list_file.Items[i].SubItems.Strings[0];
    if path <>'/' then
    begin
      IdFTP1.ChangeDir(path);
      ForceDirectories(FExePath+path);
      s1 := list_file.Items[i].Caption;
      s2 := FExePath+path+'/'+list_file.Items[i].Caption;
      IdFTP1.Get(s1,s2,True);
    end
    else
    begin
      s1 := list_file.Items[i].Caption;
      s2 := FExePath+'/'+list_file.Items[i].Caption;
      IdFTP1.Get(s1,s2,True);
      //记录失败项
      FIniFile.WriteString('error',list_file.Items[i].Caption,'成功');
    end;
    except
      //记录失败项
      FIniFile.WriteString('error',list_file.Items[i].Caption,'失败');
    end;
  end;
  Label4.Caption := '所有文件更新完毕！';
  DeleteFile(FExePath+'update.ini');
  CopyFile(PChar(FExePath+'update_new.ini'),PChar(FExePath+'update.ini'),False);
end;

procedure TfrmMain.LoadIni;
begin
  ld_host.Text := FIniFile.ReadString('coninfo','host','******');
  ld_username.Text := FIniFile.ReadString('coninfo','user','******');
  ld_psw.Text := FIniFile.ReadString('coninfo','psw','******');
  ld_port.Text := FIniFile.ReadString('coninfo','port','21');
  cb_mode.ItemIndex := FIniFile.ReadInteger('coninfo','mode',1);
  FMainExe := FIniFile.ReadString('coninfo','main','Main.exe');
  FParam := FIniFile.ReadString('coninfo','param','');
end;

procedure TfrmMain.SaveIni;
begin
  FIniFile.WriteString('coninfo','host',ld_host.Text);
  FIniFile.WriteString('coninfo','user',ld_username.Text);
  FIniFile.WriteString('coninfo','psw',ld_psw.Text);
  FIniFile.WriteString('coninfo','port',ld_port.Text);
  FIniFile.WriteInteger('coninfo','mode',cb_mode.ItemIndex);
end;

end.