Re: [twsocket] Found a bug and made a fix in function UrlDecode
Arno, ... try the following code and let me know how it works for you, The code works for me. But should not the first overload directive be inside the conditional define? Regards Bjørnar -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] Found a bug and made a fix in function UrlDecode
Bjørnar Nielsen wrote: Arno, ... try the following code and let me know how it works for you, The code works for me. But should not the first overload directive be inside the conditional define? Yes, it's better inside, corrected. Just updated the svn repository. -- Arno Garrels -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
[twsocket] Detecting POP3 protocol state and disconnecting
A few POP3 related questions... 1. How am I supposed to detect when POP3 component has disconnected or what state is it in? OnSessionClosed appears to trigger BEFORE it disconnects but after QUIT is sent (not logical for me, should be the last one to trigger) and what seems to trigger at the disconnection time is OnRequestDone when TPop3Request is pop3Quit which appears to be the last one to happen. But if I immediately during this event start new batch of POP3 commands (by setting new server, new port etc.) it may sometimes trigger pop3 already connected and sometimes won't. So obviously it is still connected. Also, is it good to fill pop3 component with new server name while in event handler or how to implement a small time-delay (to fill it right after the event is handled)? Next I tried OnStateChange event. It is supposed to update SyncPop3Cli1-State or perhaps ProtocolState right? Well... it does trigger but SyncPop3Cli1-State always returns pop3Ready (defined as 0). Same goes for SyncPop3Cli1-ProtocolState - whenever I read it it always says pop3Disconnected. So why these are not updated or how to read them? Finally, I tried SyncPop3Cli1-Connected - which always returns true. I could start 2-3 pop3 components for 2-3 servers rather than waiting for first one to finish, but that is rather dumb idea if protocol state can be detected. 2. What good is TimeOut property for? It is obviously not for timeout like for example waiting for server response because you have to use TTimer for that. I also tried to see if it will be used for DNS lookup or something like that but it doesn't seem to have any effect... -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] DNS Problem
Arno Garrels wrote: So multiple calls to DnsLookup from the same thread context are serialized. In other words, DnsLookup always returns immediately, however Win32 API WSAAsyncGetHostByName serializes multiple requests from the same thread context internally. This may trigger OnDnsLookupDone delayed but does not block a thread. A workaround was to write your own name resolution that uses multiple threads. Thank you Arno Now I understand the structure better But, in any case, the thread should not block in my software right? Eric -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] Detecting POP3 protocol state and disconnecting
Zvone wrote: A few POP3 related questions... 1. How am I supposed to detect when POP3 component has disconnected or what state is it in? OnSessionClosed is the event to initiate a reconnect delayed (see below). OnSessionClosed appears to trigger BEFORE it disconnects but after QUIT is sent (not logical for me, should be the last one to trigger) and what seems to trigger at the disconnection time is OnRequestDone when TPop3Request is pop3Quit which appears to be the last one to happen. But if I immediately during this event start new batch of POP3 commands (by setting new server, new port etc.) it may sometimes trigger pop3 already connected and sometimes won't. So obviously it is still connected. Yes, one cannot rely on these events always trigger in the same order. Also it might happen that you get a response to the QUIT request but the server doesn't close the connection. In this case after some timeout exceeded you have to close the connection yourself. In latest ICS V7 there's an basic timeout feature implemented in TWSocket that you could use for this purpose, this feature has to be explicitly enabled by setting conditional define EXPERIMENTAL_TIMEOUT in OverbyteIcsDefs.inc. When built with EXPERIMENTAL_TIMEOUT TPop3Cli.CtrlSocket will get three new properties and one new event: property TimeoutSampleInterval: LongWord property ConnectTimeout: LongWord property IdleTimeout: LongWord property OnTimeout: TTimeoutEvent Also, is it good to fill pop3 component with new server name while in event handler or how to implement a small time-delay (to fill it right after the event is handled)? The correct way to reconnect (delayed) is: In the OnSessionClosed event handler post a custom Windows message to some Window or to the form handle and from the message handler populate properties and start the next session. [schnip] I could start 2-3 pop3 components for 2-3 servers rather than waiting for first one to finish, but that is rather dumb idea if protocol state can be detected. No problem to have multiple instances, you can use the same event handlers for all instances, just use the Sender argument and cast it to, for instance, TPop3Cli. 2. What good is TimeOut property for? It is obviously not for timeout like for example waiting for server response because you have to use TTimer for that. I also tried to see if it will be used for DNS lookup or something like that but it doesn't seem to have any effect... This timeout only works (if at all) with the synchronous methods or TSyncPop3Cli. -- Arno Garrels -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] DNS Problem
Eric Fleming Bonilha wrote: Arno Garrels wrote: So multiple calls to DnsLookup from the same thread context are serialized. In other words, DnsLookup always returns immediately, however Win32 API WSAAsyncGetHostByName serializes multiple requests from the same thread context internally. This may trigger OnDnsLookupDone delayed but does not block a thread. A workaround was to write your own name resolution that uses multiple threads. Thank you Arno Now I understand the structure better But, in any case, the thread should not block in my software right? Correct, the calling thread won't be blocked. -- Arno Garrels -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] DNS Problem
Correct, the calling thread won't be blocked. Arno, I´m having a problem with a customer, and I sucessfully reproduced the same problem here. I really believe that it is related to DNS Lookup. Here is what is happening: - I have a communication thread that spawns all TCP client sockets, so, all communication messages are carried by this thread, not by the main thread - I can have several instaces of TCP clients spawned by the communication thread The test that I did: - I have some TCP sockets connected to fixed IP addresses and receiving realtime video data (MPEG-4 video stream) - When I try to connect to a DNS address from dnsalias.com, all the data that was receiving from all TCP sockets stops for 2 seconds. I believe that this time is the DNS lookup because if I try to ping the address it takes about 2 seconds to resolve the address You told me that the thread would not blobk, but it stops receiving all TCP data during the DNS lookup? Any idea on why does it happens? If I make my own DNS lookup using threads, would it solve? Thanks! Eric -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] DNS Problem
Correct, the calling thread won't be blocked.
Arno,
I have checked the ICS code, and I found this:
OverbyteIcsWSocket.pas on line 7290 (TCustomWSocket.Connect)
if not FAddrResolved then begin
{ The next line will trigger an exception in case of failure }
sin.sin_addr.s_addr :=
WSocket_Synchronized_ResolveHost(AnsiString(FAddrStr)).s_addr;
FAddrResolved := TRUE;
end;
So, when I first call connect, it will try to resolve the host by using
WSocket_Synchronized_ResolveHost
This is a sync routine, it just quits when it resolves, and in that case,
the thread will be blocked until the address is resolved.
That is the problem that I´m having, because on my customer site it takes 2
seconds to resolve the ip address, and during this time, all TCP
communications are dead, because the .Connect method is called from the
communication thread context
Am I using an old version of ICS? I´m using version 7 with D2010.
If this is the right way of ICS working, then I think I have to make a DNS
lookup thread
Thanks
Eric
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Re: [twsocket] DNS Problem
Eric,
Correct, the calling thread won't be blocked.
Arno,
I have checked the ICS code, and I found this:
OverbyteIcsWSocket.pas on line 7290 (TCustomWSocket.Connect)
if not FAddrResolved then begin
{ The next line will trigger an exception in case of
failure } sin.sin_addr.s_addr :=
WSocket_Synchronized_ResolveHost(AnsiString(FAddrStr)).s_addr;
FAddrResolved := TRUE;
end;
So, when I first call connect, it will try to resolve the host by
using WSocket_Synchronized_ResolveHost
Sorry I misunderstood. I thought you used method DnsLookup.
So in this case it is simple to fix, call method DnsLookup and connect
with a dotted IP address from the OnDnsLookupDone event handler.
--
Arno Garrels
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Re: [twsocket] DNS Problem
Sorry I misunderstood. I thought you used method DnsLookup. So in this case it is simple to fix, call method DnsLookup and connect with a dotted IP address from the OnDnsLookupDone event handler. Hi Arno Thanks for the clarification So, if I use the method DnsLookup all the requests will be serialized correct? If I try to connect to several different DNS that takes several seconds to resolve (I tested in my customer site and it actually takes 5 to 6 seconds to resolve), it means that if it is serialized, the last request will take very long to respond Instead, if I spaw a thread (and release after use) for each lookup and use the routine WSocketResolveHost from the new thread context, I can response many addresses all at once, correct? Is it safe to use WSocketResolveHost routine? I can translate the result to dotted IP address easily Thanks Eric -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] DNS Problem
Eric, Sorry I misunderstood. I thought you used method DnsLookup. So in this case it is simple to fix, call method DnsLookup and connect with a dotted IP address from the OnDnsLookupDone event handler. Hi Arno Thanks for the clarification So, if I use the method DnsLookup all the requests will be serialized correct? Correct, and it won't block the calling thread. If I try to connect to several different DNS that takes several seconds to resolve (I tested in my customer site and it actually takes 5 to 6 seconds to resolve), it means that if it is serialized, the last request will take very long to respond That's true as well. Instead, if I spaw a thread (and release after use) for each lookup and use the routine WSocketResolveHost from the new thread context, I can response many addresses all at once, correct? In parallel yes, the more CPUs or cores the better. Is it safe to use WSocketResolveHost routine? I can translate the result to dotted IP address easily Yes, it is safe, however I would consider to use WSocket_gethostbyname as well (more work). -- Arno Garrels -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] DNS Problem
Yes, it is safe, however I would consider to use WSocket_gethostbyname as well (more work). What is the differenc? I See that wsocket_gethostbyname returns more information, but is there a reason to use it instead of the other method? Thanks Eric -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] DNS Problem
Eric Fleming Bonilha wrote: Yes, it is safe, however I would consider to use WSocket_gethostbyname as well (more work). What is the differenc? I See that wsocket_gethostbyname returns more information, but is there a reason to use it instead of the other method? WSocket_Synchronized_ResolveHost includes checks like WSocketIsDottedIP() etc. which doesn't require to run in a worker thread. I would start a worker thread only in case wsocket_gethostbyname must be called. If you want to optimize this a bit more you could use a thread pool, since creating threads takes time as well. Perhaps something like TIcsAsyncDnsLookup that I wrote for async name resolution with IPv6 recently, it has a thread pool, however uses the GetAddrInfo() API which was easy to change: http://svn.overbyte.be:8443/svn/ics/branches/icsipv6/Delphi/Vc32/OverbyteIcsWSocket.pas User and password both ics. -- Arno Garrels -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
