Detecting a mobile browser in ASP.NET

Introduction

A simple function to detect if a user vesting your site is on a mobile device or not.

Background

This is my first CodeProject article. The articles on this site have helped me out so much in learning .NET. I just hope this can help someone out as well.

I needed the ability to detect if a user was browsing from a mobile device or a normal web browser and redirect to the appropriate version of my site. I found very little ASP.NET tutorials that worked. So I decided to take a few different methods and language options I found on the net and put them into one simple ASP.NET method.

Using the Code

It is just a static boolean method that gets called, isMobileBrowser():

public static bool isMobileBrowser()
{
    //GETS THE CURRENT USER CONTEXT
    HttpContext context = HttpContext.Current;

    //FIRST TRY BUILT IN ASP.NT CHECK
    if (context.Request.Browser.IsMobileDevice)
    {
        return true;
    }
    //THEN TRY CHECKING FOR THE HTTP_X_WAP_PROFILE HEADER
    if (context.Request.ServerVariables["HTTP_X_WAP_PROFILE"] != null)
    {
        return true;
    }
    //THEN TRY CHECKING THAT HTTP_ACCEPT EXISTS AND CONTAINS WAP
    if (context.Request.ServerVariables["HTTP_ACCEPT"] != null && 
        context.Request.ServerVariables["HTTP_ACCEPT"].ToLower().Contains("wap"))
    {
        return true;
    }
    //AND FINALLY CHECK THE HTTP_USER_AGENT 
    //HEADER VARIABLE FOR ANY ONE OF THE FOLLOWING
    if (context.Request.ServerVariables["HTTP_USER_AGENT"] != null)
    {
        //Create a list of all mobile types
        string[] mobiles =
            new[]
                {
                    "midp", "j2me", "avant", "docomo", 
                    "novarra", "palmos", "palmsource", 
                    "240x320", "opwv", "chtml",
                    "pda", "windows ce", "mmp/", 
                    "blackberry", "mib/", "symbian", 
                    "wireless", "nokia", "hand", "mobi",
                    "phone", "cdm", "up.b", "audio", 
                    "SIE-", "SEC-", "samsung", "HTC", 
                    "mot-", "mitsu", "sagem", "sony"
                    , "alcatel", "lg", "eric", "vx", 
                    "NEC", "philips", "mmm", "xx", 
                    "panasonic", "sharp", "wap", "sch",
                    "rover", "pocket", "benq", "java", 
                    "pt", "pg", "vox", "amoi", 
                    "bird", "compal", "kg", "voda",
                    "sany", "kdd", "dbt", "sendo", 
                    "sgh", "gradi", "jb", "dddi", 
                    "moto", "iphone"
                };

        //Loop through each item in the list created above 
        //and check if the header contains that text
        foreach (string s in mobiles)
        {
            if (context.Request.ServerVariables["HTTP_USER_AGENT"].
                                                ToLower().Contains(s.ToLower()))
            {
                return true;
            }
        }
    }

    return false;
}

Points of Interest

As you can see, the above code is written in new syntax. But, it can easily be changed to work on any version of .NET. Instead of using the short hand array initializer, use new string[] {} (instead of new[] {}).

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

Vincent Van Zyl

Team Leader
Blueworld Communities

South Africa

Member

I am fairly new to programming as I began programming in asp.net and C# in 2005.

But I have learned a lot in a very short space of time thanks to code project and sitepoint. I work in a very fast past company which also helped speed things up

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My vote of 1

fawad

22:56 13 Mar '12

or less require a comment
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New devices

Boci

9:53 5 Dec '11

These newer devices should be included in the array: `"ipod", "ipad", "android", "rim tablet", "webos"` I suggest, do not use `ToLower()` on the array elements. Instead of it, write it with lower case characters in the array declaration. Also instead of `ToLower()` you can use `ToLowerInvariant()`, to avoid globalization warnings.
Sign In·View Thread·Permalink	5.00/5 (1 vote)

Re: New devices

blagoja

0:50 29 Dec '11

Thanks Boci, I noticed that this was not working on opera mini on my android device so I added "android" and "opera mini" in the array and it works fine now
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thanks

hugorafael

9:58 20 Jun '11

is a good code understandable and short. just one thing i would add is the use of Linq technology insteaad of foreach so I will use this code: return (from br in mobiles where context.Request.ServerVariables["HTTP_USER_AGENT"].Contains(br) select br).Count() > 0; and avoid to exit the loop before it finish(just a guess)
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Thanks

Nikhil_Patel123

4:01 27 Apr '11

thanks , you saved my time. Nikhil Patel Software Developer
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Improved version

Harvo

15:08 23 Nov '10

Hi,

I cleaned up the code a bit, improved its performance, added it as an extension method, and spruced
up the user-agent detection logic based on content found from http://www.detectmobilebrowser.com. The full
code is shown below.

By the way, the optimization that was mentioned previously to treat as non-mobile if the browser
is not "Unknown" is not correct, that should be removed. (From my iPhone, for example,
Request.Browser.IsMobileDevice returns false, and Request.Browser.Browser is something like "AppleMac-XXX".)

Cheers,

Harvo

    public static class HttpRequestBaseExtensions
    {
        #region Private Fields
 
        // These regular expressions retrieved from http://detectmobilebrowser.com/ "Open source mobile phone detection".
        private static Regex MobileBrowsers = new Regex(@"android|avantgo|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\\/|plucker|pocket|psp|symbian|treo|up\\.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino", RegexOptions.IgnoreCase | RegexOptions.Multiline);
        private static Regex MobileApps = new Regex(@"1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\\-(n|u)|c55\\/|capi|ccwa|cdm\\-|cell|chtm|cldc|cmd\\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\\-s|devi|dica|dmob|do(c|p)o|ds(12|\\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\\-|_)|g1 u|g560|gene|gf\\-5|g\\-mo|go(\\.w|od)|gr(ad|un)|haie|hcit|hd\\-(m|p|t)|hei\\-|hi(pt|ta)|hp( i|ip)|hs\\-c|ht(c(\\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\\-(20|go|ma)|i230|iac( |\\-|\\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\\/)|klon|kpt |kwc\\-|kyo(c|k)|le(no|xi)|lg( g|\\/(k|l|u)|50|54|e\\-|e\\/|\\-[a-w])|libw|lynx|m1\\-w|m3ga|m50\\/|ma(te|ui|xo)|mc(01|21|ca)|m\\-cr|me(di|rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\\-2|po(ck|rt|se)|prox|psio|pt\\-g|qa\\-a|qc(07|12|21|32|60|\\-[2-7]|i\\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\\-|oo|p\\-)|sdk\\/|se(c(\\-|0|1)|47|mc|nd|ri)|sgh\\-|shar|sie(\\-|m)|sk\\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\\-|v\\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\\-|tdg\\-|tel(i|m)|tim\\-|t\\-mo|to(pl|sh)|ts(70|m\\-|m3|m5)|tx\\-9|up(\\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|xda(\\-|2|g)|yas\\-|your|zeto|zte\\-", RegexOptions.IgnoreCase | RegexOptions.Multiline);
 
        #endregion
 
        public const string ViewMobileSiteCookieName = "ViewMobile";
 
        /// <summary>
        /// Determines if the request emanated from a mobile-device client; and stores the result in a cookie on the response.
        /// </summary>
        /// <param name="request"></param>
        /// <param name="Response"></param>
        /// <returns></returns>
        public static bool IsMobileClient(this HttpRequestBase request, HttpResponseBase Response)
        {
            bool isMobile = false;
            bool isCookieSet = false;
            var viewMobileCookie = request.Cookies[ViewMobileSiteCookieName];
 
            if (viewMobileCookie != null && bool.TryParse(viewMobileCookie.Value, out isMobile))
            {
                isCookieSet = true;
            }
            else if (request.Browser.IsMobileDevice)
            {
                isMobile = true;
            }
            else if (request.ServerVariables["HTTP_X_WAP_PROFILE"].IsNotEmpty())
            {
                isMobile = true;
            }
            else if
                (
                    request.ServerVariables["HTTP_ACCEPT"].IsNotEmpty()
                    &&
                    (
                        request.ServerVariables["HTTP_ACCEPT"].ToLower().Contains("wap")
                        || request.ServerVariables["HTTP_ACCEPT"].ToLower().Contains("wml+xml")
                    )
                )
            {
                isMobile = true;
            }
            else if (request.ServerVariables["HTTP_USER_AGENT"].IsNotEmpty())
            {
                string userAgent = request.ServerVariables["HTTP_USER_AGENT"];
                isMobile = ((MobileBrowsers.IsMatch(userAgent) || MobileApps.IsMatch(userAgent.Substring(0, 4))));
            }
 
            // Store the result as a cookie.
            if(!isCookieSet)
                Response.Cookies.Add(new HttpCookie(ViewMobileSiteCookieName, isMobile.ToString()));
 
            return isMobile;
        }
    }

Re: Improved version

Daniel Gidman

9:04 5 May '11

Thats nice. Where is the "IsNotEmpty()" extension method defined however? Harvo wrote: .IsNotEmpty()
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Re: Improved version

Harvo

10:02 5 May '11

Ah, one of the many extension methods I carry around: public static bool IsNotEmpty(this string instance) { return instance != null && instance.Length > 0; } Just a handier way of saying "!string.IsNullOrEmpty(value)". Harvo
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Re: Improved version

sanilpnair

4:03 8 Aug '11

Hi , how to call IsMobileClient(?,?); what are the parameters? Please tell me Sanil
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Re: Improved version

Le Cong Thanh

6:19 16 Sep '11

You can make it like this: if (HttpRequestBaseExtensions.IsMobileClient(base.Request.RequestContext.HttpContext.Request, base.Request.RequestContext.HttpContext.Response)) { // do something }
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Great article

ORamses

0:42 5 Sep '10

This helped me greatly! Thank you for your efforts in putting this together.
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some little enhancements

smartcatxxx

7:02 11 Oct '09

You could add the following check after the context.Request.Browser.IsMobileDevice block:

if (!context.Request.Browser.Browser.Equals("Unknown", StringComparison.InvariantCultureIgnoreCase)) return false;

Those 2 blocks of code cover the set of cases when ASP.NET knows what kind of browser is dealing with. The additional checks based on the server variables are needed ONLY if ASP.NET is clueless about the browser. This should cut down the false positives to basically 0. E.g. if you are dealing with IE, the browser capabilities code will know that therefore will return false without going through checking the user agent strings and labeling IE MSN-branded as mobile browser, as reported by EricLaw. Also, the check for HTTP_ACCEPT could check for "wml+xml", not only for "wap".

Since we could be talking about a high traffic website, I would like to suggest some small performance enhancements:

a. move the array containing the user agent strings outside the isMobileBrowser() method e.g.:

private static readonly string[] arrMobilePhones = new string[] {"midp", "j2me", "avant", "docomo", ...etc };

This way it gets created only once upon application startup (rather than with each method call) then it stays in memory until the application shuts down or runs into some memory allocation issues/crashes.

b. foreach is almost twice slower than going through an array index-based, so:

string strUserAgent = context.Request.ServerVariables["HTTP_USER_AGENT"];
for (int i=0 ; i < mobiles.Length ; i++)
{
if (strUserAgent.IndexOf(mobiles[i], StringComparison.InvariantCultureIgnoreCase) >= 0) return true;
}

Detect Mobile Infomation

Amimpat

1:12 31 Jul '09

You can easily detect that a request is coming from which mobile device using http://www.51degrees.mobi/Products/NETMobileAPI

This API gives detailed information of the device making the request and also has the facility to redirect user automatically to mobile specific page when request in coming from mobile device.

I have found this very useful and easy to implement in mobile website developments.

Let me know if you face any issues in usage.

Thanks

Re: Detect Mobile Infomation [modified]

DutchMafia

3:44 13 Aug '09

I downloaded and looked at the solution from the link you provided (http://www.51degrees.mobi[^]). Awesome! Your solution is 10x better than what is provided in this article. I think the article author had the right idea. Anyone that is developing for mobile needs to download your solution to test ther user agents on their mobile devices.

There is also:

http://davidjberman.com/blogs/csharp/archive/2008/04/10/how-to-detect-a-mobile-web-browser-using-asp-net-2-0.aspx[^]

Which says:

"HttpContext.Current.Request.Browser will give you a HttpBrowserCapabilities object, which has a property IsMobileDevice. The value of this property will be true if a mobile browser is detected."

And detects these mobile browsers automatically:

http://www.asp.net/mobile/tested-devices/[^]

modified on Thursday, August 13, 2009 9:50 AM

Re: Detect Mobile Infomation

Amaresh Jois

18:46 5 Aug '10

I have used this and found it useful. The .NET open source API has now moved to Codeplex. Now you can download it from here http://51degrees.codeplex.com/releases[^] Thanks
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Re: Detect Mobile Infomation

Amaresh Jois

2:40 27 Aug '10

There is a 4 minute video on the usage of 51degrees.mobi foundation .NET open source toolkit to Enhance your existing website to contain mobile pages. Video (3:43 minutes): http://www.youtube.com/watch?v=b4io5KB4Qt0
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This code contains false positives!

EricLaw

8:28 14 Jul '09

Anyone who installs the MSN-branded version of IE will find sites that use this code are treated as mobile browsers. "pt" is a substring of "MSNOptimized" which appears in this user agent. Given the list of two-letter strings in this code, I'm sure there are other false-positives as well. :(
Sign In·View Thread·Permalink	2.00/5 (1 vote)

Re: This code contains false positives!

Wendy Youngblood

6:58 30 Mar '10

"NEC" causes IE 8 to be seen as a mobile browser. I just removed this line from my code. Now Chrome, Firefox, Safari and IE versions 6+ (all I tested) are not detected as mobile browsers. I'm not sure what else "NEC" affects, but I'd rather have mobile view the full site than a desktop view the mobile. For safety, my site has a "View Full Site" link that will switch to the full site without having to choose to do so on each page.

Overall the code works great for me. Thanks!!

Bug

thezone123

22:44 7 Apr '09

if (context.Request.ServerVariables["HTTP_USER_AGENT"].ToLower().Contains(s.ToLower())) The last ToLower in the above statement should be removed because it will cause it to incorrectly identify IE desktop as a mobile device.
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Re: Bug

mgbaldwin

1:42 13 Jul '09

you probably want to remove both `ToLower()` parts, or certain matches will never work as the string array has some upper case entries. I'm using it with the comparison as simply: `if (context.Request.ServerVariables["HTTP_USER_AGENT"].Contains(s))` and it works fine.
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