Delphi中如何直接读取http://xxx/xxx.xx上的文件？可能是图片或其他文件？

Question

见标题。

Answer 1

unit HTTPGet;interfaceuses
  Windows, Messages, SysUtils, Classes, WinInet;type
  TOnProgressEvent = procedure(Sender: TObject; TotalSize, Readed: Integer) of object;
  TOnDoneFileEvent = procedure(Sender: TObject; FileName: String; FileSize: Integer) of object;
  TOnDoneStringEvent = procedure(Sender: TObject; Result: String) of object;  THTTPGetThread = class(TThread)
  private
    FTAcceptTypes,
    FTAgent,
    FTURL,
    FTFileName,
    FTStringResult,
    FTUserName,
    FTPassword,
    FTPostQuery,
    FTReferer: String;
    FTBinaryData,
    FTUseCache: Boolean;    FTResult: Boolean;
    FTFileSize: Integer;
    FTToFile: Boolean;    BytesToRead, BytesReaded: DWord;    FTProgress: TOnProgressEvent;    procedure UpdateProgress;
  protected
    procedure Execute; override;
  public
    constructor Create(aAcceptTypes, aAgent, aURL, aFileName, aUserName, aPassword, aPostQuery, aReferer: String;
                       aBinaryData, aUseCache: Boolean; aProgress: TOnProgressEvent; aToFile: Boolean);
  end;  THTTPGet = class(TComponent)
  private
    FAcceptTypes: String;
    FAgent: String;
    FBinaryData: Boolean;
    FURL: String;
    FUseCache: Boolean;
    FFileName: String;
    FUserName: String;
    FPassword: String;
    FPostQuery: String;
    FReferer: String;
    FWaitThread: Boolean;    FThread: THTTPGetThread;
    FError: TNotifyEvent;
    FResult: Boolean;    FProgress: TOnProgressEvent;
    FDoneFile: TOnDoneFileEvent;
    FDoneString: TOnDoneStringEvent;    procedure ThreadDone(Sender: TObject);
  public
    constructor Create(aOwner: TComponent); override;
    destructor Destroy; override;    procedure GetFile;
    procedure GetString;
    procedure Abort;
  published
    property AcceptTypes: String read FAcceptTypes write FAcceptTypes;
    property Agent: String read FAgent write FAgent;
    property BinaryData: Boolean read FBinaryData write FBinaryData;
    property URL: String read FURL write FURL;
    property UseCache: Boolean read FUseCache write FUseCache;
    property FileName: String read FFileName write FFileName;
    property UserName: String read FUserName write FUserName;
    property Password: String read FPassword write FPassword;
    property PostQuery: String read FPostQuery write FPostQuery;
    property Referer: String read FReferer write FReferer;
    property WaitThread: Boolean read FWaitThread write FWaitThread;    property OnProgress: TOnProgressEvent read FProgress write FProgress;
    property OnDoneFile: TOnDoneFileEvent read FDoneFile write FDoneFile;
    property OnDoneString: TOnDoneStringEvent read FDoneString write FDoneString;
    property OnError: TNotifyEvent read FError write FError;
  end;procedure Register;implementation

Answer 2

//  THTTPGetThreadconstructor THTTPGetThread.Create(aAcceptTypes, aAgent, aURL, aFileName, aUserName, aPassword, aPostQuery, aReferer: String;
                                  aBinaryData, aUseCache: Boolean; aProgress: TOnProgressEvent; aToFile: Boolean);
begin
  FreeOnTerminate := True;
  inherited Create(True);  FTAcceptTypes := aAcceptTypes;
  FTAgent := aAgent;
  FTURL := aURL;
  FTFileName := aFileName;
  FTUserName := aUserName;
  FTPassword := aPassword;
  FTPostQuery := aPostQuery;
  FTReferer := aReferer;
  FTProgress := aProgress;
  FTBinaryData := aBinaryData;
  FTUseCache := aUseCache;  FTToFile := aToFile;
  Resume;
end;procedure THTTPGetThread.UpdateProgress;
begin
  FTProgress(Self, FTFileSize, BytesReaded);
end;procedure THTTPGetThread.Execute;
var
  hSession, hConnect, hRequest: hInternet;
  HostName, FileName: String;
  f: File;
  Buf: Pointer;
  dwBufLen, dwIndex: DWord;
  Data: Array[0..$400] of Char;
  TempStr: String;
  RequestMethod: PChar;
  InternetFlag: DWord;
  AcceptType: LPStr;  procedure ParseURL(URL: String; var HostName, FileName: String);    procedure ReplaceChar(c1, c2: Char; var St: String);
    var
      p: Integer;
    begin
      while True do
       begin
        p := Pos(c1, St);
        if p = 0 then Break
        else St[p] := c2;
       end;
    end;  var
    i: Integer;
  begin
    if Pos('http://', LowerCase(URL)) <> 0 then
      System.Delete(URL, 1, 7);    i := Pos('/', URL);
    HostName := Copy(URL, 1, i);
    FileName := Copy(URL, i, Length(URL) - i + 1);    if (Length(HostName) > 0) and (HostName[Length(HostName)] = '/') then
      SetLength(HostName, Length(HostName) - 1);
  end; procedure CloseHandles;
 begin
   InternetCloseHandle(hRequest);
   InternetCloseHandle(hConnect);
   InternetCloseHandle(hSession);
 end;begin
  try
    ParseURL(FTURL, HostName, FileName);    if Terminated then
     begin
      FTResult := False;
      Exit;
     end;    if FTAgent <> '' then
     hSession := InternetOpen(PChar(FTAgent),
       INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0)
    else
     hSession := InternetOpen(nil,
       INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0);    hConnect := InternetConnect(hSession, PChar(HostName),
      INTERNET_DEFAULT_HTTP_PORT, PChar(FTUserName), PChar(FTPassword), INTERNET_SERVICE_HTTP, 0, 0);    if FTPostQuery = '' then RequestMethod := 'GET'
    else RequestMethod := 'POST';    if FTUseCache then InternetFlag := 0
    else InternetFlag := INTERNET_FLAG_RELOAD;    AcceptType := PChar('Accept: ' + FTAcceptTypes);
    hRequest := HttpOpenRequest(hConnect, RequestMethod, PChar(FileName), 'HTTP/1.0',
                PChar(FTReferer), @AcceptType, InternetFlag, 0);    if FTPostQuery = '' then
     HttpSendRequest(hRequest, nil, 0, nil, 0)
    else
     HttpSendRequest(hRequest, 'Content-Type: application/x-www-form-urlencoded', 47,
                     PChar(FTPostQuery), Length(FTPostQuery));    if Terminated then
     begin
      CloseHandles;
      FTResult := False;
      Exit;
     end;    dwIndex  := 0;
    dwBufLen := 1024;
    GetMem(Buf, dwBufLen);    FTResult := HttpQueryInfo(hRequest, HTTP_QUERY_CONTENT_LENGTH,
                              Buf, dwBufLen, dwIndex);    if Terminated then
     begin
      FreeMem(Buf);
      CloseHandles;     
      FTResult := False;
      Exit;
     end;    if FTResult or not FTBinaryData then
     begin
      if FTResult then
        FTFileSize := StrToInt(StrPas(Buf));      BytesReaded := 0;      if FTToFile then
       begin
        AssignFile(f, FTFileName);
        Rewrite(f, 1);
       end
      else FTStringResult := '';      while True do
       begin
        if Terminated then
         begin
          if FTToFile then CloseFile(f);
          FreeMem(Buf);
          CloseHandles;          FTResult := False;
          Exit;
         end;        if not InternetReadFile(hRequest, @Data, SizeOf(Data), BytesToRead) then Break
        else
         if BytesToRead = 0 then Break
         else
          begin
           if FTToFile then
            BlockWrite(f, Data, BytesToRead)
           else
            begin
             TempStr := Data;
             SetLength(TempStr, BytesToRead);
             FTStringResult := FTStringResult + TempStr;
            end;           inc(BytesReaded, BytesToRead);
           if Assigned(FTProgress) then
            Synchronize(UpdateProgress);
          end;
       end;      if FTToFile then
        FTResult := FTFileSize = Integer(BytesReaded)
      else
       begin
        SetLength(FTStringResult, BytesReaded);
        FTResult := BytesReaded <> 0;
       end;      if FTToFile then CloseFile(f);       
     end;    FreeMem(Buf);    CloseHandles;
  except
  end;
end;// HTTPGetconstructor THTTPGet.Create(aOwner: TComponent);
begin
  inherited Create(aOwner);
  FAcceptTypes := '*/*';
  FAgent := 'UtilMind HTTPGet';
end;destructor THTTPGet.Destroy;
begin
  Abort;
  inherited Destroy;
end;procedure THTTPGet.GetFile;
var
  Msg: TMsg;
begin
  if not Assigned(FThread) then
   begin
    FThread := THTTPGetThread.Create(FAcceptTypes, FAgent, FURL, FFileName, FUserName, FPassword, FPostQuery, FReferer,
                                     FBinaryData, FUseCache, FProgress, True);
    FThread.OnTerminate := ThreadDone;
    if FWaitThread then
    while Assigned(FThread) do
     while PeekMessage(Msg, 0, 0, 0, PM_REMOVE) do
      begin
        TranslateMessage(Msg);
        DispatchMessage(Msg);
      end;
   end
end;

Answer 3

procedure THTTPGet.GetString;
var
  Msg: TMsg;
begin
  if not Assigned(FThread) then
   begin
    FThread := THTTPGetThread.Create(FAcceptTypes, FAgent, FURL, FFileName, FUserName, FPassword, FPostQuery, FReferer,
                                     FBinaryData, FUseCache, FProgress, False);
    FThread.OnTerminate := ThreadDone;
    if FWaitThread then
     while PeekMessage(Msg, 0, 0, 0, PM_REMOVE) do
      begin
        TranslateMessage(Msg);
        DispatchMessage(Msg);
      end;
   end
end;procedure THTTPGet.Abort;
begin
  if Assigned(FThread) then
   begin
    FThread.Terminate;
    FThread.FTResult := False;
   end;
end;procedure THTTPGet.ThreadDone(Sender: TObject);
begin
  FResult := FThread.FTResult;
  if FResult then
   if FThread.FTToFile then
    if Assigned(FDoneFile) then FDoneFile(Self, FThread.FTFileName, FThread.FTFileSize) else
   else
    if Assigned(FDoneString) then FDoneString(Self, FThread.FTStringResult) else   
  else
   if Assigned(FError) then FError(Self);
  FThread := nil;
end;procedure Register;
begin
  RegisterComponents('UtilMind', [THTTPGet]);
end;end.

Answer 4

方法一：用TNMHTTP.Get('http://xxxx.xom')
方法二：TWebBrowser.OnDocumentComplete
方法三：写HTML脚本就可实现，只是听说，没试过。
给点分吧。：）
我爱Delphi！