Question

I am creating a PHP API for an Android application and want to make it so the API only proceses requests from Android devices. Is there some sort of logic I could use to make this happen?

Answer 1

you can use Mobile_Detect which is a lightweight PHP class for detecting mobile devices. It uses the User-Agent string combined with specific HTTP headers to detect the mobile environment. by using this PHP lib you can dectect following devices:

Phones
* isiPhone()
* isBlackBerry()
* isHTC()
* isNexus()
* isDellStreak()
* isMotorola()
* isSamsung()
* isSony()
* isAsus()
* isPalm()
* isGenericPhone()

Tablets
* isBlackBerryTablet()
* isiPad()
* isKindle()
* isSamsungTablet()
* isHTCtablet()
* isMotorolaTablet()
* isAsusTablet()
* isNookTablet()
* isAcerTablet()
* isYarvikTablet()
* isGenericTablet()

Operating systems
* isAndroidOS()
* isBlackBerryOS()
* isPalmOS()
* isSymbianOS()
* isWindowsMobileOS()
* isiOS()
* isFlashLiteOS()
* isJavaOS()
* isNokiaOS()
* iswebOS()
* isbadaOS()
* isBREWOS()

Mobile browsers
* isChrome()
* isDolfin()
* isOpera()
* isSkyfire()
* isIE()
* isFirefox()
* isBolt()
* isTeaShark()
* isBlazer()
* isSafari()
* isMidori()
* isGenericBrowser()

or see this tutorial for Detecting Mobile Devices Using PHP:
http://www.hand-interactive.com/resources/detect-mobile-php.htm