CODEWITHSUNDEEP
windowsterminal-services
Ian Boyd
Ian Boyd

Reputation: 256901

How to detect, from browser, if user is running in Remote Desktop session?

Is there a ways to check inside a browser (e.g. javascript) if the user is running inside a Remote Desktop session?

If the user is running their browser inside a Remote Desktop (i.e. Terminal Services), i want to disable animations on the web-site.

If this were a native application, as opposed to a web-site, i could perform this checking using:

//Native code
isRemoteSession = GetSystemMetrics( SM_REMOTESESSION );

or

//Managed Code:
isRemoteSession = System.Windows.Forms.SystemInformation.TerminalServerSession;

Is there a similar check that can be done inside the browser?

Note: Assume for the purposes of this discussion that the browser we're talking about is Internet Explorer 8.

Update One: Perhaps something in How can you get the terminal service client machine name from javascript?

Upvotes: 15

Views: 16638

Answers (6)

Ercksen
Ercksen

Reputation: 669

You can use the following media query:

@media screen and (prefers-reduced-motion: reduce) { . . . }

This condition can also hold for non-RDP sessions, but as your intention is to disable all animations, this type of query is probably exactly what you're looking for.

Upvotes: 6

user186188
user186188

Reputation: 5

This should not be done or decided by your application. On RDP client (like MS RDC), user can choose to disable animations etc. User can also disable these on server side (Terminal server or RDP host)

Upvotes: -2

Maxy-B
Maxy-B

Reputation: 2832

My solution is to use CSS @media queries for minimum and maximum values of the color media feature. Based on experiment, RDP only seems to have 5 bits per color, rather than the full 8 bits per color of your typical desktop.

This solution is, of course, not perfect, because you'll get lots of false positives from people who aren't on RDP, but just happen to have low color-depth displays. However:

  • If you are in a relatively controlled environment like a corporate intranet, you might feel more confident that "low color depth" = "RDP".
  • Many of the visual elements that need adjusting for RDP on a web-page, need adjusting precisely because of the low color depth (gradients, fade outs, animation, etc.), and so it actually makes sense to test for color depth rather than RDP per se.

Here is an example that works for me in recent version of Firefox and Chrome. See the screenshot below.

<!DOCTYPE html>
<html>
    <head>
        <title>Test RDP detection</title>
        <style type="text/css">
            @media all { li.color { display: none; } }
            @media all and (min-color: 1) { li.color.color-depth-1 { display: block; } }
            @media all and (min-color: 2) { li.color.color-depth-2 { display: block; } }
            @media all and (min-color: 3) { li.color.color-depth-3 { display: block; } }
            @media all and (min-color: 4) { li.color.color-depth-4 { display: block; } }
            @media all and (min-color: 5) { li.color.color-depth-5 { display: block; } }
            @media all and (min-color: 6) { li.color.color-depth-6 { display: block; } }
            @media all and (min-color: 7) { li.color.color-depth-7 { display: block; } }
            @media all and (min-color: 8) { li.color.color-depth-8 { display: block; } }

            /* 5 bits per color seems to be the max for RDP */
            @media all and (max-color: 5) {
                .not-rdp { display: none; }
            }
            @media all and (min-color: 6) {
                .rdp-only { display: none; }
            }
        </style>
    </head>
    <body>
        <p>This page uses CSS <tt>@media</tt> queries to detect whether you
            are viewing it over RDP&mdash;heuristically, by looking at the
            color depth of your display.</p>

        <ul>
            <li class="color color-depth-1">Your display is not monochrome!</li>
            <li class="color color-depth-2">Your display has at least 2 bits per color.</li>
            <li class="color color-depth-3">Your display has at least 3 bits per color.</li>
            <li class="color color-depth-4">Your display has at least 4 bits per color.</li>
            <li class="color color-depth-5">Your display has at least 5 bits per color.</li>
            <li class="color color-depth-6">Your display has at least 6 bits per color.</li>
            <li class="color color-depth-7">Your display has at least 7 bits per color.</li>
            <li class="color color-depth-8">Your display has at least 8 bits per color.</li>
        </ul>

        <p>You are <span class="not-rdp">not</span> using RDP.</p>
        <p class="rdp-only">This is only visible over RDP.</p>
    </body>
</html>

screenshot showing test page with and without RDP

Yet another approach along these lines is to use javascript to examine the value of the screen.colorDepth variable.

Upvotes: 13

Sheng Jiang 蒋晟
Sheng Jiang 蒋晟

Reputation: 15281

You can probably expose the detection code via an ActiveX or BHO (e.g. assign a property to the window object in BHO) if you use IE.

Otherwise if you are using an ActiveX player to play animation, check the player's documentation to see if it automatically adjust frame rate under remote desktop.

You can always offer a low bandwidth version of your web site and instruct the user choose the web site instead of the regular web site if the video playback is not satisfactory.

For tips in writing a terminal service-aware graphics app, check graphic effects consideration, and the general performance guidelines

Upvotes: 1

Trevor Ian Peacock
Trevor Ian Peacock

Reputation: 824

I'm assuming you are talking about a specific company terminal server, not any terminal server. You could not serve animations to the specific IP address of the TS.

Upvotes: 0

Remko
Remko

Reputation: 7340

Perhaps you can read the SESSIONNAME environment variable? For a console session it should be CONSOLE and for an RDP session it should be RDP-TCP followed by a number.

Upvotes: 0

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