Setting up URL Rewrite rule

Question

I've a rewrite role in my web.config, and it's redirect to mydomain.com/de.

But now I will replace the action de/{R:1} with the user language, where I can get from {HTTP_ACCEPT_LANGUAGE} . But this is a string of language and looks like fr-CH,**fr**;q=0.8,en;q=0.6,de;q=0.4,de-CH;q=0.2/

So it's there possibility to get the out only the **fr** of this string?

Thanks for any help.

This is my role:

<rule name="mydomain.com" stopProcessing="true" >
    <match url="(.*)" />
        <conditions>
            <add input="{URL}" pattern="/en/|/de/" negate="true" />
        </conditions>
        <action type="Redirect" url="de/{R:1}"  />
</rule>

Answer 1

In the past i have used the following rule to redirect to a language based page

<rewrite>           
        <rules>               
            <rule name="RedirectToLang" enabled="true" stopProcessing="true">
                <match url=".*" />
                <action type="Redirect" url="{R:0}/{HTTP_ACCEPT_LANGUAGE}" appendQueryString="true" />
                <conditions>
                    <add input="{HTTP_ACCEPT_LANGUAGE}" pattern=".+" />
                </conditions>
            </rule>
        </rules> 
    </rewrite>