Lightweight Device-Detection in ASP

ASP.NET determines the capabilities of every browser which sends requests to the server independant of if the request originates from a mobile device or a desktop computer. If browsers are detected correctly and mobile devices are identified depends on the configuration of the server.

Thanks for the news ;-) There are of course still many sites stilling using classic asp - it is these we are catering for here rather than ASP.NET developers.

i'm using below function
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Function isMobile (ua,accept)

If(_

instr(accept,"text/vnd.wap.wml")>0 _
or instr(Lcase(ua),"symbian")>0 _
or instr(Lcase(ua),"series")>0 _
or instr(Lcase(ua),"nokia")>0 _
or instr(Lcase(ua),"mot-")>0 _
or instr(Lcase(ua),"motorola")>0 _
or instr(Lcase(ua),"lg-")>0 _
or instr(Lcase(ua),"lge")>0 _
or instr(Lcase(ua),"nec-")>0 _
or instr(Lcase(ua),"lg/")>0 _
or instr(Lcase(ua),"samsung")>0 _
or instr(Lcase(ua),"sie-")>0 _
or instr(Lcase(ua),"sec-")>0 _
or instr(Lcase(ua),"sgh-")>0 _
or instr(Lcase(ua),"sonyericsson")>0 _
or instr(Lcase(ua),"sharp")>0 _
or instr(Lcase(ua),"windows ce")>0 _
or instr(Lcase(ua),"portalmmm")>0 _
or instr(Lcase(ua),"o2-")>0 _
or instr(Lcase(ua),"docomo")>0 _
or instr(Lcase(ua),"philips")>0 _
or instr(Lcase(ua),"panasonic")>0 _
or instr(Lcase(ua),"sagem")>0 _
or instr(Lcase(ua),"smartphone")>0 _
or instr(Lcase(ua),"up.browser")>0 _
or instr(Lcase(ua),"up.link")>0 _
or instr(Lcase(ua),"googlebot-mobile")>0 _
or instr(Lcase(ua),"googlebot")>0 _
or instr(Lcase(ua),"slurp")>0 _
or instr(Lcase(ua),"spring")>0 _
or instr(Lcase(ua),"alcatel")>0 _
or instr(Lcase(ua),"sendo")>0 _
or instr(Lcase(ua),"blackberry")>0 _
or instr(Lcase(ua),"opera mini")>0 _
or instr(Lcase(ua),"opera 2")>0 _
or instr(Lcase(ua),"netfront")>0 _
or instr(Lcase(ua),"mobilephone mm")>0 _
or instr(Lcase(ua),"vodafone")>0 _
or instr(Lcase(ua),"avantgo")>0 _
or instr(Lcase(ua),"palmsource")>0 _
or instr(Lcase(ua),"siemens")>0 _
or instr(Lcase(ua),"toshiba")>0 _
or instr(Lcase(ua),"i-mobile")>0 _
or instr(Lcase(ua),"asus")>0 _
or instr(Lcase(ua),"ice")>0 _
or instr(Lcase(ua),"kwc")>0 _
or instr(Lcase(ua),"htc")>0 _
or instr(Lcase(ua),"softbank")>0 _
or instr(Lcase(ua),"mozilla/5.0 (x11; u; linux i686; en-us; rv:1.8.0.7) gecko/20060909 firefox/1.5.0.7")>0 _
or instr(Lcase(ua),"playstation")>0 _
or instr(Lcase(ua),"nitro")>0 _
or instr(Lcase(ua),"iphone")>0 _
or instr(Lcase(ua),"ipod")>0 _
or instr(Lcase(ua),"google wireless transcoder")>0 _
or instr(Lcase(ua),"t-mobile")>0 _
or instr(Lcase(ua),"obigo")>0 _
or instr(Lcase(ua),"brew")>0 _
or instr(Lcase(ua),"yahooseeker")>0 _
or instr(Lcase(ua),"msmobot")>0 _
or instr(Lcase(ua),"novarra")>0 _
or instr(Lcase(ua),"skp")>0 _
or instr(Lcase(ua),"openweb")>0 _

) _
Then

isMobile=True
else
isMobile=False
end if

End function

You might want to optimize that a bit. ASP does not short-circuit any logical tests in an IF statement. All the tests will be done even if a match is found on the first. You should do the lcase() before the statement and maybe have a separate IF statement for the most common browsers first.

Can I use this code so that when a mobile user is detected that it redirects them to my more mobile friendly website?

You sure can!

Doesn't work with opera, detects it as mobile even when it is a desktop.

mobile_agents = Array("w3c ", "acs-", "alav", "alca", "amoi", "audi", "avan", "benq", "bird", "blac", "blaz", "brew", "cell", "cldc", "cmd-", "dang", "doco", "eric", "hipt", "inno", "ipaq", "java", "jigs", "kddi", "keji", "leno", "lg-c", "lg-d", "lg-g", "lge-", "maui", "maxo", "midp", "mits", "mmef", "mobi", "mot-", "moto", "mwbp", "nec-", "newt", "noki", "oper", "palm", "pana", "pant", "phil", "play", "port", "prox", "qwap", "sage", "sams", "sany", "sch-", "sec-", "send", "seri", "sgh-", "shar", "sie-", "siem", "smal", "smar", "sony", "sph-", "symb", "t-mo", "teli", "tim-", "tosh", "tsm-", "upg1", "upsi", "vk-v", "voda", "wap-", "wapa", "wapi", "wapp", "wapr", "webc", "winw", "winw", "xda", "xda-")

look for the one "oper" i changed mine to "operamini"

How could you allow mobile users to visit the full site if they wanted without being automatically redirected back to the mobile site?

Nice article!

As admin stated earlier, many sites are still using ASP. Mine is one of them.

In reply to shaunjbutler's question, even if it was posted long ago, I can tell you that I simply changed the very last part of the code:

If mobile_browser>0 Then
   Response.Write("Mobile!")
Else
   Response.Write("Not mobile!")
End If

To

If mobile_browser>0 Then
   Response.Redirect("*/looksmobile.asp")
Else
   Response.Redirect("www.ourstandardwebsite.com")
End If

The looksmobile.asp site presents the user with a choice whether or not they want to view the mobile version of the site. Then saves their choice in a cookie, and sends them to their preferred site in the future.

Can I use this with an existing desktop browser website? The problem is, the website is in ASP.Net.

The script also doesn't work with my phone. It's a Sony Ericsson C902 with NetFront browser (a lot of new phones have similar technology). Problem is, this mobile browser returns a value for mobile_ua as "mozi" and therefore thinks it's a desktop Mozilla variant.

I know that mobile redirects work on my phone since pages like Google and bbc.co.uk implement it successfully. Any ideas? I only have the one phone on which to test my proposed mobile site so it's annoying that I can't get it to work!!

If it helps, the HTTP_USER_AGENT for my phone is:
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.7) Gecko/20060909 Firefox/1.5.0.7 MG(Novarra-Vision/7.3)

Hmmm, it looks like there is a transcoder messing up your UA string:

The (Novarra-Vision/7.3) bit gives it away...

The usual UA strings for that device can be seen at the bottom of this page .

Fair point, but the first two strings (at the bottom of that reference page) would surely also return a value for mobile_ua of "mozi" and therefore if my UA string was one of them, I'd have the same problem. Or am I reading that wrong?

BTW, I have checked with 3 of my friends who all have the same model of phone and all 3 display the same UA string as mine! Which, as you pointed out, isn't listed on the page you referenced. So either the UA strings on that page are out of date, or C902 phones are now displaying something different! Very annoying....

It's likely that you are all connecting to the Internet via the same transcoding proxy. What operator are you with?

In this case, I would edit the line

.Pattern = "(up.browser|up.link|mmp|symbian|smartphone|midp|wap|phone|windows ce|pda|mobile|mini|palm)"

to include the string Netfront:

.Pattern = "(up.browser|up.link|mmp|symbian|smartphone|midp|wap|phone|windows ce|pda|mobile|mini|palm|netfront)"

Although it won't work where your UA has been mangled by a transcoder.

We're all with Vodafone. At the moment I'm using a workaround by inserting the line:
If InStr(Request.ServerVariables("HTTP_USER_AGENT"), "Novarra") > 0 Then mobile_browser = mobile_browser+1

after the for...next loop. This will detect all Novarra devices (which are mobile or handheld anyway). Not the best solution but it works for now. Just wondered if there was a neater way of doing this, especially since there might be other mangled UA strings out there!

Vodafone uses the novarra transcoder...

Welcome to the world of transcoders - unsolicited transcoding is the bane of mobile web developers, and the mere mention of them is enough to cause blood vessels to burst in some developer circles.

Usually you can change the APN setting of your phone so that you don't go via the Vodafone transcoder. However, the average user won't know how to do this, or even what an APN is, or even what a transcoder is, or that something unintended by the content provider is happening... In Ireland, the APN: live.vodafone.ie goes via the transcoder, whereas isp.vodafone.ie does not transcode.

Same applies in the UK as far as I know, but I'm not sure of the details of the Vodafone UK APNs.

If you felt compelled, you might visit http://ta-da.mobi to test your phone after you update your APN setting.

in the above code

> mobile_agents = Array

I don't see the iphone listed as an agent?? however it detects the iphone as a mobile device.

What agent defines an Iphone?

I don't want to treat the Iphone as a mobile device

Agent of my Blackberry 8310 Curve:
HTTP_USER_AGENT - Mozilla/4.0 (compatible; MSIE6.0; Windows NT 5.1; SV1)
Help...

How would I amend the original script so that if the source was an iPHONE it would not include it as a mobile device, as all this shows is XML !!

You could try adding the string "ipho" to the list of strings above to check for - I've no idea if this will conflict with any desktop browser UAs though

Hiya,

Just a quick note, if you are using the script posted in the 3rd comment you need to make sure that you do not use this line:
or instr(Lcase(ua),"ice")>0

Reason is that this may cause issues with IE:

Request.UserAgent dump for ie7:
+++++Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; OfficeLiveConnector.1.3; OfficeLivePatch.0.0)

Alex

i am having problems with this script when it tries to load the site in the IE7 browser. it seems like it takes forever to load. i thought maybe it was having a conflict with some other scripts on the page, so i commented out the first two lines as suggested. however, i get the same result. is there a hack to make IE ignore the script?

Hello Guys

For above sample code

- It may not catch all mobile browsers as there are a lot of them.
- You need to keep updating user agents when new devices are introduced.
- Not easy to parse user agents to get detailed information about the mobile device such as the manufacturer, model, screen height & width, and image formats supported. This type of information is necessary to customize page layout for specific mobile device.

Please take a look at http://51degrees.codeplex.com/
it provides auto redirection to mobile optimized pages when request is coming from mobile device. It makes use of WURFL mobile device database. For redirection there is no need to modify existing ASP/ASP.NET web application pages as above.

Apart from this it also gives upto date mobile capability information like manufacturer, model, screen height & width, image formats supported etc., which helps you to customize your pages for best mobile output.

I have found this very useful for my mobile web development.

Please give a try it will help you a lot.

Thanks
Amit Patel

The latest release of http://51degrees.codeplex.com/ supports Multiple Mobile Redirect Locations.
Below is sample web.config settings to show how easy it is to implement mobile detection and rediection without modifying any of your existing asp.net web pages.

In this example MobileDeviceManufacturer is used as the property. This properties are exposed through the HttpRequest classes Browser property. Both WURFL capabilities and ASP.NET Browser properties can be used with the property attribute. If none of the match and the requesting device is a mobile device then the mobileHomePageUrl will be used.

<redirect firstRequestOnly="true"
mobileHomePageUrl="~/Mobile/Default.aspx"
timeout="20"
devicesFile="~/App_Data/Devices.dat"
mobilePagesRegex="/[Apple|RIM|Nokia|Mobile]/">
<locations>
<!--Send iphone to their own home page.-->
<location url="~/Apple/Default.aspx">
<add property="MobileDeviceManufacturer" matchExpression="Apple"/>
</location>
<!--Send blackberry to their own home page.-->
<location url="~/RIM/Default.aspx">
<add property="MobileDeviceManufacturer" matchExpression="RIM"/>
</location>
<!--Send nokia to their own home page.-->
<location url="~/Nokia/Default.aspx">
<add property="MobileDeviceManufacturer" matchExpression="Nokia"/>
</location>
</locations>
</redirect>

Great script. I've been using it for a few years.

My Question: How would I exclude a device? Like the iPad.

I appreciate your efforts and time.

Hi Ive just added webos to the Regex for the latest Palm Pre and generation of webOS devices and this seems now to recognise Palm Pre with webos

added webos

ith Regex
.Pattern = "(up.browser|up.link|mmp|symbian|smartphone|midp|wap|phone|windows ce|pda|mobile|mini|palm|webos)"

What is the difference b/w regex list and mobile_agents list in the code?
Is regex list name of browser and mobile_agents name of cell phone providers?

Regards