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使用Indy 10中TIdHTTP的例子:
代码
uses
IdHttp; . . . function HttpGet(const Url: string; var Html: string): Boolean; var HttpClient: TIdHTTP; begin Result := False; HttpClient := TIdHTTP.Create(nil); try Html := HttpClient.Get(Url); Result := True; except on e: Exception do begin end; end; HttpClient.Free; end; Indy采用的是同步I/O的方式,而且在连接超时控制方面存在bug,因此TIdHttp.Get()有时会发生陷入死锁无法返回的问题。
使用ICS中THttpCli的例子: 代码
uses
HttpProt; . . . function HttpGet(const Url: string; var Html: string): Boolean; var HttpClient: THttpCli; DataLen: Int64; FailMsg: string; begin Result := False; HttpClient := THttpCli.Create(nil); HttpClient.URL := Url; HttpClient.NoCache := True; HttpClient.RcvdStream := TMemoryStream.Create; try try HttpClient.Get; DataLen := HttpClient.RcvdStream.Size; SetLength(Html, DataLen); HttpClient.RcvdStream.Position := 0; HttpClient.RcvdStream.Read(PChar(Html)^, DataLen); Result := True; except on E: EHttpException do begin FailMsg := Format('Failed : %d %s', [HttpClient.StatusCode, HttpClient.ReasonPhrase]); end else raise; end; finally HttpClient.RcvdStream.Free; HttpClient.RcvdStream := nil; HttpClient.Free; end; end; ICS使用的是异步I/O,其TFtpClient组件有Timout属性可以对连接超时进行控制,而THttpCli组件没有。但可以采用在定时器中调用THttpCli.Abort()取消连接的方式控制超时,也可以显式调用异步方法:
var HttpClient: THttpCli; DataLen: Int64; FailMsg: string; Tick: Cardinal; begin . . . Tick := GetTickCount; try try HttpClient.GetASync; while HttpClient.State <> httpReady do begin if GetTickCount - Tick > 30*1000 then begin HttpClient.Abort; Exit; end; Application.ProcessMessages; end; . . .
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