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Restored from previous forum. Originally posted by Justin.

I want to make a program that downloads some files from internet, i use the wininet.api, sometimes the server stops sending data and the program will hang in the Internetreadfile waiting forever for a response.

Wich would be the best approach to set a timeout and have the ability to retry or skip the file?, has anyone tried something similar?

maybe using 2 threads, one that downloads and another to check if the data is being recieved?

or using a callback function?, the wininet has this feature:
http://msdn.microsoft.com/library/en-us ... LLBACK.asp

i don't understand some parameters of that function, maybe monitoring the INTERNET_STATUS_RESPONSE_RECEIVED message?

thanks for any help.

Restored from previous forum. Originally posted by PB.

> I want to make a program that downloads some files from internet, i use the
> wininet.api, sometimes the server stops sending data and the program will
> hang in the Internetreadfile waiting forever for a response.

Try the following tip and see if the files being downloaded still hang... if they
don't, then your current download routine could just be a bit buggy or something.

viewtopic.php?t=628

PB - Registered PureBasic Coder

Restored from previous forum. Originally posted by Justin.

Thanks, maybe i can get some ideas from that thread.

But the problem is that i need to do a POST request, sending some special data and a refer to get the file, i don't think that function can do post requests.

Any ideas using the wininet functions?

Restored from previous forum. Originally posted by Justin.

Maybe a more direct question..

Does anybody know what the parameter dwContext means in this callback function?

INTERNET_STATUS_CALLBACK
This function is a prototype for an application-defined status callback function.

typedef void (CALLBACK *INTERNET_STATUS_CALLBACK) (
HINTERNET hInternet,
DWORD_PTR dwContext,
DWORD dwInternetStatus,
LPVOID lpvStatusInformation,
DWORD dwStatusInformationLength
);

Parameters
hInternet
[in] Handle for which the callback function is being called.

dwContext
[in] Address of an unsigned long integer value that contains the application-defined context value associated with the hInternet parameter.

dwInternetStatus
[in] Unsigned long integer value that contains the status code that indicates why the callback function is being called. The following table shows the values for the dwInternetStatus parameter.

Restored from previous forum. Originally posted by Justin.

Thanks to the thread PB suggested i figured out how to do it using 2 threads.

I think it is better than the example in that thread because if i undesrtanded well the timeout there is the maximun time that the whole download process can take (wich timeout do you use for a 50MB file?)

Here the timeout is the max time without recieving data, a timeout of 60 sec means that if no data is recieved during 60 sec the process will stop.

The example downloads a web page to a string, it can be easily modificated to download a binary file to disk.

There is a 5 sec timeout, if you don't click Ok during that time the download stops.

#INTERNET_OPEN_TYPE_DIRECT = 1
#INTERNET_DEFAULT_HTTP_PORT = 80
#INTERNET_SERVICE_HTTP = 3
#INTERNET_FLAG_NO_CACHE_WRITE = 67108864

#TimeOut = 5000

Global GotData, TimedOut, strread$

;Downloads the file(1Kb each time)
Procedure I_ReadFile(openreqhandle)
buf$=Space(1024)
Repeat
InternetReadFile_(openreqhandle,@buf$,1024,@bread)
strread$=strread$+Left(buf$,bread)
MessageRequester(Str(bread),buf$,0)
Until bread=0
GotData = #TRUE
EndProcedure

;Checks every milliseconds if the data recieved has changed
Procedure Timeout(millisecs)
Repeat
oldstrread$=strread$
Delay(millisecs)
Until oldstrread$=strread$
TimedOut = #TRUE
EndProcedure

host.s="yahoo.com" ;host
geturl.s="/" ;rest of url to download

;initialize internet functions (no error checking)
tophandle = InternetOpen_("PB",#INTERNET_OPEN_TYPE_DIRECT,"","",0)
connecthandle = InternetConnect_(tophandle,host,#INTERNET_DEFAULT_HTTP_PORT,"","",#INTERNET_SERVICE_HTTP,0,0)
openreqhandle = HttpOpenRequest_(connecthandle,"GET",geturl,"","",0,#INTERNET_FLAG_NO_CACHE_WRITE,0)
sendreq = HttpSendRequest_(openreqhandle,"",0,"",0)

TimedOut = #FALSE
GotData = #FALSE

TimThreadID = CreateThread(@Timeout(), #TimeOut)
DownThreadID = CreateThread(@I_ReadFile(), openreqhandle)

Repeat
Until TimedOut Or GotData

;close internet handles
InternetCloseHandle_(openreqhandle)
InternetCloseHandle_(connecthandle)
InternetCloseHandle_(tophandle)

If TimedOut
MessageRequester("","Timeout",0)
EndIf

If GotData
MessageRequester("","All data recieved.",0)
EndIf

If TimedOut = #FALSE : KillThread(TimThreadID) : EndIf
If GotData = #FALSE : KillThread(DownThreadID) : EndIf