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2007-09-14 10:16:40 PM
delphi23
Environment
Delphi 7 with update 1 (Indy 9)
Vista Business
IIS 7
ISAPI dlls
I am trying to write a web service that calls another web service both of
which are written with the environment listed. I have a client that can
call each web service respectively. This works indicating that the web
services are functional. Each web service only returns a string as I am
only trying to get this to work, and there is no other functionality built
in at this point. I then modify web service 1 so it will call web service
2. Everything compiles just fine. Now the client calls web service 1 which
calls web service 2, which should return a string to web service 1 which is
then returned to the client. When the client calls web service 1, which
then attempts to call web service 2, I am getting the following error
'Project WebServiceClient.exe raised exception ERemotableException with
message 'Access violation at address 037F1D0D in module 'WebService1.dll'.
Read of address 000000AC'. If I convert the two web service to WAD
executables, this process works like a champ. I have looked thoroughly on
the internet for examples but have come up short. It would appear in my
research that this is entirely possible. I was wondering if anyone has
knowledge on this or if anyone has a working example of how to do this. I
tried to attached my sample code but the newsgroup did not all this.
Thanks.
John White
 

Hello John,
This issue has come up before. I suspect that the AV in WebService1 is
actually related to the fact that WebService1 could not do an HTTP POST to
WebService2 but failed to catch/handle some error/exception. I don't recall
how the issue was resolved (maybe google has cached the interaction) but (if
I remember correctly) it was something about the fact that WebService1 or
IIS has to be configured in some particular way to allow one ISAPI DLL to
POST to another. Again, if I recall correctly, the issue is not WebService
specific: it is a generic "how to have one ISAPI dll POST to another". It
could have been related to the fact that ISAPI DLLs run under another user
account and that account does not have right to do a POST... or something
along these lines.
I'll try to do a search to see if I can find the thread.
Cheers,
Bruneau.
 

Does anyone have an example of one delphi web service consuming another
delphi web service? Thanks.
John White
"Jean-Marie Babet" <XXXX@XXXXX.COM>writes