[Mono-dev] Environment.GetEnvironmentVariable() not working in Linux ASP.NET app

Wed Nov 9 11:17:04 EST 2011

Hi Oscar,

thanks for your detailed explanation.

To further clear things up, I have always used the button "Apply System-Wide" in all of my tests. The necessary environment variables should therefore be available system wide.

Best regards,
Martin

> From: oskar.berggren at gmail.com
> Date: Wed, 9 Nov 2011 12:38:20 +0100
> Subject: Re: [Mono-dev] Environment.GetEnvironmentVariable() not working in Linux ASP.NET app
> To: test051102 at hotmail.com
> CC: mono-devel-list at lists.ximian.com
> 
> 2011/11/9 H . <test051102 at hotmail.com>:
> > Hi Robert,
> >
> > I didn't know that Linux hides certain environment variables from a process
> > depending on the identity it is running in. I guess that the only choice for
> 
> It doesn't, not as such. Environment variables are inherently per
> process, and this is the same in Windows. When a process is launched
> it generally inherits the environment variables from its parent, with
> any requested modifications.
> 
> Then it boils down to how are environment variables configured
> administratively for a particular system? The concept of system-wide
> and per-user environment variables is an abstraction built on the
> above facility, and there is no fundamental requirement for that (e.g.
> it would be possibly to build a system where they are set and applied
> per executable name, or something entirely different).
> 
> In Windows there is a control panel app to set them per user or
> system-wide. In Linux each distro may have different methods, but
> basically any "system-wide" environment settings will be stored in
> e.g. /etc/environment, and it then becomes the responsibility of a few
> "core" processes to read and apply these settings to themselves during
> e.g. login. "Regular" applications launched by the user will then
> inherit them.
> 
> Concerning proxy settings with Ubuntu 10.04 as example: These are in
> System->Preferences->Network Proxy. These are by default per user
> (since it's under Preferences, not Administration). However, the
> button "Apply System-Wide" is provided. Clicking that then gives me:
> 
> oskar$ cat /etc/environment
> PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"
> LANG="en_US.UTF-8"
> http_proxy="http://ff:8080/"
> 
> 
> oskar$ sudo su - www-data
> www-data$ printenv|grep -i prox
> http_proxy=http://ff:8080/
> 
> 
> Notice how the proxy is applied also for the www-data user. However,
> to make the web server see the change it would have to be restarted.
> Possibly a reboot is the easiest way to ensure they are re-read.
> 
> 
> /Oskar
> 
> 
> 
> > platform indepent ASP.NET apps is then to configure proxy settings via
> > web.config. Alternatively, it is possible to set the WebClient object's
> > Proxy property to null in case no proxies should be used. This is most
> > likely valid in intranet environments. The current Mono/master supports both
> > of these methods.
> >
> >
> > Best regards,
> > Martin
> >
> >
> >
> >> To: mono-devel-list at lists.ximian.com
> >> From: robertj at gmx.net
> >> Date: Sat, 5 Nov 2011 11:47:51 +0100
> >> Subject: Re: [Mono-dev] Environment.GetEnvironmentVariable() not working
> >> in Linux ASP.NET app
> >>
> >> Hi Martin,
> >>
> >> On 05.11.2011 09:48, H . wrote:
> >> >
> >> > Hi Robert,
> >> >
> >> > I am using XSP2& MonoDevelop to debug.
> >>
> >> You have to restart your user session if you've changed
> >> the proxy settings. Being environment-based, these settings
> >> won't propagate to running processes.
> >>
> >> >
> >> > Based on the answers I think that it might be a Linux related issue.
> >> >
> >> > I have implemented extensive proxy support for WebClient and it's
> >> > underlying classes in Mono/master. This code is based on the no_proxy
> >> > environment variable in Linux. The question is, how can we obtain the
> >> > list of proxies to bypass in Linux? Is there a consistend way to do
> >> > this for standard Linux apps AND Linux ASP.NET apps?
> >>
> >> There is no standard regarding proxy configuration besides
> >> those two environment variables "http_proxy" and "no_proxy".
> >>
> >> Tools that make use of proxies (wget, curl, browsers) may
> >> have other proprietary configurations, but at the and they
> >> all support these environment variables.
> >>
> >> Robert
> >>
> >> >
> >> >
> >> > Best regards, Martin
> >> >
> >> >
> >> >
> >> >> To: mono-devel-list at lists.ximian.com From: robertj at gmx.net Date:
> >> >> Thu, 3 Nov 2011 15:47:37 +0100 Subject: Re: [Mono-dev]
> >> >> Environment.GetEnvironmentVariable() not working in Linux ASP.NET
> >> >> app
> >> >>
> >> >> On 03.11.2011 14:12, H . wrote:
> >> >>>
> >> >>> Hi Robert,
> >> >>
> >> >>> thanks for your hints.
> >> >>>
> >> >>> The link sent describes how environment variables can be set up
> >> >>> in Ubuntu. Of course, nobody would try to manually set up
> >> >>> environment variables when trying to configure proxies. This is
> >> >>> done by using System>Settings>Network Proxy. After that, Ubuntu
> >> >>> sets up the necessary environment variables. In case of the
> >> >>> no_proxy environment variable this can be tested by issuing "echo
> >> >>> $no_proxy" on the command line.
> >> >>
> >> >> Yes, you may see it on *your* own command line, as a normal user,
> >> >> but the web server (you didn't specify which one, so we can't
> >> >> help) may have its own environment default settings.
> >> >>
> >> >> A common way to solve that (if Ubuntu's config tools don't provide
> >> >> a facility to set either global or web server specific vars) is to
> >> >> set this env var globally and manually.
> >> >>
> >> >> Robert
> >> >>
> >> >> _______________________________________________ Mono-devel-list
> >> >> mailing list Mono-devel-list at lists.ximian.com
> >> >> http://lists.ximian.com/mailman/listinfo/mono-devel-list
> >> >
> >> >
> >> >
> >> >
> >> > _______________________________________________ Mono-devel-list
> >> > mailing list Mono-devel-list at lists.ximian.com
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> >>
> >>
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