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From Steve Loughran <ste...@apache.org>
Subject Re: Disconnected Development
Date Fri, 22 Dec 2006 22:29:18 GMT
Gilles Scokart wrote:
> Unfortunately, I think that detecting that you are offline or online is
> something quiet difficult.  So the user will have to pass some information
> in his ant command line.
> 

the big problem is deciding if a system is offline. I've lots of low 
level win32 stuff related to network state and while you can be 100% 
sure you are offline when there is no lan or modem, the presence of any 
of those things (or a WLAN, or an ipaddr outside the 169.* range) does 
not mean that you are online. If you cannot reliably tell WTF is going 
on in C++, you don't stand a chance in java. Hitting remote sites is the 
only way to be sure.


Ant1.7 has an IsReachable condition that does a ping, which wont go 
through firewalls. If you want to check a remote http server, then GET 
is all you have

How Ant does it:

   <target name="probe-offline">
     <condition property="offline">
       <or>
         <isset property="offline"/>
         <not>
           <http url="http://www.apache.org/"/>
         </not>
       </or>
     </condition>
     <echo level="verbose"> offline=${offline}</echo>
   </target>


-steve

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