> (1) What happens if I use ContnetRangeBegin and the server doesn't > support ranges (ex: if I'm downloading the results of a script)? Will I > end up with the whole document append to the already downloaded portion > of the document?
You'll get an error. > (2) I noticed there's a AcceptRanges property that's set up by THttpCli > from the headers it receives while processing a request. I supose this > is server-dependent. Can I make use of this to determine if ranges are > supported? I think so. > (3) In the code running after a failed download I'm removing the last > portion of the received data, just in case it's corrupted. I noticed > this behavior in a freeware download manager I used to use some time > ago. But now I'm asking: is this really necessary? HTTP traffic travels > over TCP and TCP is supposed to be an checksummed, reliable protocol. Is > the probability of receiving corrupt data high enough to make such > radical surgery useful? If so, is tail-trimming the best solution, or > should I implement some other kind of checksumming to make sure no > portion of the code is actually corrupt (after all, corruption might > occur anywhere in the document, not just in the last received portion). You are right, I don't see any reason to throw away part of the received data. By TCP protocol specification, only valid data is delivered to the application. If you get it, it is correct data. -- Contribute to the SSL Effort. Visit http://www.overbyte.be/eng/ssl.html -- [EMAIL PROTECTED] http://www.overbyte.be ----- Original Message ----- From: "Cosmin Prund" <[EMAIL PROTECTED]> To: "ICS support mailing" <twsocket@elists.org> Sent: Thursday, November 16, 2006 10:47 AM Subject: [twsocket] HttpCli & ContentRangeBegin > Hello. > > I've build a "download manager" module for my application arround > THttpCli and I'm making use of ContentRangeBegin to resume failed > downloads. It all works very nice and smooth, and all my downloads > resume fine. Unfortunately my downloads only fail when I unplug the > network cable from my computer OR when I disable my network adapter... > and I don't think those are the most common causes of disconnections for > the average user! So I'll have to ask about "abnormal" situations, just > to make sure I'm getting things right: > > (1) What happens if I use ContnetRangeBegin and the server doesn't > support ranges (ex: if I'm downloading the results of a script)? Will I > end up with the whole document append to the already downloaded portion > of the document? > (2) I noticed there's a AcceptRanges property that's set up by THttpCli > from the headers it receives while processing a request. I supose this > is server-dependent. Can I make use of this to determine if ranges are > supported? > (3) In the code running after a failed download I'm removing the last > portion of the received data, just in case it's corrupted. I noticed > this behavior in a freeware download manager I used to use some time > ago. But now I'm asking: is this really necessary? HTTP traffic travels > over TCP and TCP is supposed to be an checksummed, reliable protocol. Is > the probability of receiving corrupt data high enough to make such > radical surgery useful? If so, is tail-trimming the best solution, or > should I implement some other kind of checksumming to make sure no > portion of the code is actually corrupt (after all, corruption might > occur anywhere in the document, not just in the last received portion). > > Thanks, > Cosmin Prund > -- > To unsubscribe or change your settings for TWSocket mailing list > please goto http://www.elists.org/mailman/listinfo/twsocket > Visit our website at http://www.overbyte.be -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
