BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  HTTP buffer error Goto page 1, 2  Next          BorlandTalk.com Forum Index -> Delphi Internet Winsock View previous topic :: View next topic   Author Message Paul Guest Posted: Thu Nov 18, 2004 9:02 pm    Post subject: HTTP buffer error Hi all I am tyring to download a stream with idHTTP.get(aurl,St), but Í allways get a 'Buffer error'. The stream size is approx 15k , the receivebuffer size is 32 k. I am trying for 5 days now without success. (newbie) Can anyone give me some hints/ examples? I'm using indy 9 with D7. TIA Paul Back to top Remy Lebeau (TeamB) Guest Posted: Thu Nov 18, 2004 9:10 pm    Post subject: Re: HTTP buffer error "Paul" <paul.blommaerts (AT) telenet (DOT) be> wrote Quote: I am tyring to download a stream with idHTTP.get(aurl,St), but Í allways get a 'Buffer error'. Please show your actual code, and please specific the full error message. Gambit Back to top Paul Guest Posted: Thu Nov 18, 2004 9:39 pm    Post subject: Re: HTTP buffer error Hi Gambit, this is the code connection part HTTP1.Host:='localHost'; HTTP1.Request.Connection:='Keep-Alive'; HTTP1.Connect; download picture picStream:= TMemoryStream.Create; try HTTP1.Get(hUrl,picStream); image1.Picture.Bitmap.LoadFromStream(picStream); finally FreeAndNil(picStream); end; Paul Back to top Remy Lebeau (TeamB) Guest Posted: Thu Nov 18, 2004 9:44 pm    Post subject: Re: HTTP buffer error "Paul" <paul.blommaerts (AT) telenet (DOT) be> wrote Quote: HTTP1.Host:='localHost'; HTTP1.Request.Connection:='Keep-Alive'; HTTP1.Connect; You are not supposed to be using Host or Connect() directly. Only use Get() and Post(). The Host and Connect() are managed internally by Get() and Post(), based on the URL specified. Quote: HTTP1.Get(hUrl,picStream); image1.Picture.Bitmap.LoadFromStream(picStream); You did not reset the stream's Position back to 0 after downloading. HTTP1.Get(hUrl,picStream); picStream->Position = 0; // <-- here image1.Picture.Bitmap.LoadFromStream(picStream); Also, what kind of images are you actually downloading? Are they BMP files? If not, then your code won't work anyway, since the Bitmap property can only load BMP data. Gambit Back to top Paul Guest Posted: Thu Nov 18, 2004 9:55 pm    Post subject: Re: HTTP buffer error I'm trying to keep the connection open. Quote: You are not supposed to be using Host or Connect() directly. Only use Get() and Post(). The Host and Connect() are managed internally by Get() and Post(), based on the URL specified. HTTP1.Get(hUrl,picStream); picStream->Position = 0; // <-- here image1.Picture.Bitmap.LoadFromStream(picStream); You did not reset the stream's Position back to 0 after downloading. I have tried this also, but I got the error this way too. Quote: Also, what kind of images are you actually downloading? Are they BMP files? If not, then your code won't work anyway, since the Bitmap property can only load BMP data. Yes, it;s a bmp Paul Back to top Paul Guest Posted: Thu Nov 18, 2004 10:44 pm    Post subject: Re: HTTP buffer error Hi Gambit The received stream size is 0, so the problem is maybe on the server side. This instruction is used on the server side. The stream size here is approx. 15k AResponseInfo.ContentStream:= picStream; Paul Back to top Robby Tanner Guest Posted: Thu Nov 18, 2004 10:46 pm    Post subject: Re: HTTP buffer error "Paul" <paul.blommaerts (AT) telenet (DOT) be> wrote Quote: I'm trying to keep the connection open. You shouldn't. If you need to keep a connection open, use a different set of components. HTTP is for atomic functions more or less. Back to top Remy Lebeau (TeamB) Guest Posted: Thu Nov 18, 2004 10:48 pm    Post subject: Re: HTTP buffer error "Paul" <paul.blommaerts (AT) telenet (DOT) be> wrote Quote: I'm trying to keep the connection open. I realize that. However, the HTTP server itself has to support that. HTTP clients are not in control of whether the connection remains open. The server is. The client can only request whether the connection *SHOULD* stay open, but it is the server that makes the actual decision. If the server agrees, then it keeps its end of the connection open, and sends a particular header value in the Response to let the client know that it can keep its end of the connection open as well. If the server refuses, however, then it always closes its end of the connection after sending the response data, and there is nothing the client can do about that, it must close its end of the connection as well. Quote: I have tried this also, but I got the error this way too. Which specific line is producing the error? What is the full error message? Gambit Back to top Paul Guest Posted: Thu Nov 18, 2004 10:59 pm    Post subject: Re: HTTP buffer error Hi Gambit I will remove the connection part, it is set 'Keep-alive'on the server also. However, sending/receiving strings works perfect this way. I've just found that the received streamsize = 0 and the error is generated further in the program. It's not an Indy generated exception The streamsize on the server side however is approx 15k just before it is transmitted. I don't have a sniffer, so I don't know if the stream was really transmitted. Maybe the problem is on the server side. This instruction is used on the server side. AResponseInfo.ContentStream:= picStream; Should I send more params and if so, what are these params and how to use them? Paul Back to top Remy Lebeau (TeamB) Guest Posted: Fri Nov 19, 2004 12:40 am    Post subject: Re: HTTP buffer error "Paul" <paul.blommaerts (AT) telenet (DOT) be> wrote Quote: The received stream size is 0, so the problem is maybe on the server side. This instruction is used on the server side. The stream size here is approx. 15k AResponseInfo.ContentStream:= picStream; You did not show how you are setting up picStream. Please show a more complete code snippet. Gambit Back to top Remy Lebeau (TeamB) Guest Posted: Fri Nov 19, 2004 12:41 am    Post subject: Re: HTTP buffer error "Robby Tanner" <robby.tanner-remove-this-part (AT) lightsource (DOT) ca> wrote in message news:419d2652 (AT) newsgroups (DOT) borland.com... Quote: If you need to keep a connection open, use a different set of components. HTTP is for atomic functions more or less. When making repeated requests to the same server, it makes sense to keep the connection open. That is why the HTTP protocol does allow for KeepAlive connections. They have to be negotiated, though. Gambit Back to top Paul Guest Posted: Fri Nov 19, 2004 5:21 pm    Post subject: Re: HTTP buffer error This is the code on the server side try picStream:= TMemoryStream.Create; bmp:= TBitmap.Create; GetPic(bmp); bmp.SaveToStream(picStream); picStream.Position:= 0; AResponseInfo.ContentStream:= picStream; finally picStream.free; bmp.free; end; "Remy Lebeau (TeamB)" <no.spam (AT) no (DOT) spam.com> schreef in bericht news:419d40a6 (AT) newsgroups (DOT) borland.com... Quote: "Paul" <paul.blommaerts (AT) telenet (DOT) be> wrote in message news:419d267c (AT) newsgroups (DOT) borland.com... The received stream size is 0, so the problem is maybe on the server side. This instruction is used on the server side. The stream size here is approx. 15k AResponseInfo.ContentStream:= picStream; You did not show how you are setting up picStream. Please show a more complete code snippet. Gambit Back to top Paul Guest Posted: Fri Nov 19, 2004 5:24 pm    Post subject: Re: HTTP buffer error I dont have a clue how to negotiate this. Where can I find an example of a negotiation between a idHTTPclient and idHTTPserver? It would help me a lot. Paul "Remy Lebeau (TeamB)" <no.spam (AT) no (DOT) spam.com> schreef in bericht news:419d40d7 (AT) newsgroups (DOT) borland.com... Quote: "Robby Tanner" <robby.tanner-remove-this-part (AT) lightsource (DOT) ca> wrote in message news:419d2652 (AT) newsgroups (DOT) borland.com... If you need to keep a connection open, use a different set of components. HTTP is for atomic functions more or less. When making repeated requests to the same server, it makes sense to keep the connection open. That is why the HTTP protocol does allow for KeepAlive connections. They have to be negotiated, though. Gambit Back to top Remy Lebeau (TeamB) Guest Posted: Fri Nov 19, 2004 6:50 pm    Post subject: Re: HTTP buffer error "Paul" <paul.blommaerts (AT) telenet (DOT) be> wrote Quote: AResponseInfo.ContentStream:= picStream; finally picStream.free; You cannot free the stream that you assign to ContentStream. TIdHTTP requires it to remain in memory after the OnCommandGet event handler returns control back to TIdHTTP. Otherwise it won't have the stream available to transmit its data back to the client. You need to change your code to take out the call to picStream.free, ie: picStream := nil; try picStream := TMemoryStream.Create; bmp := TBitmap.Create; try GetPic(bmp); bmp.SaveToStream(picStream); picStream.Position := 0; finally bmp.free; end; AResponseInfo.ContentStream := picStream; except picStream.Free; AResponseInfo.ContentStream := nil; AResponseInfo.ResponseCode := 500; AResponseInfo.ResponseText := 'Unable to Retreive Image. ' + E.Message; end; Gambit Back to top Remy Lebeau (TeamB) Guest Posted: Fri Nov 19, 2004 6:51 pm    Post subject: Re: HTTP buffer error "Paul" <paul.blommaerts (AT) telenet (DOT) be> wrote Quote: I dont have a clue how to negotiate this. You are already doing it. All you have to do is set the Connection property to 'Keep-Alive' and everything else is automatically handled by TIdHTTP internally. 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