SOURCE CODE DOWNLOAD

Click here to download all the example source code, I have released it under the MIT license, so feel free to build on top of it or use it in your own project.

QUICK START

• Download and unzip into a folder.
• Hooray! There is no database involved, so just follow through each of the files contained within.
• But take note that the zip file does not contain a copy of the Mobile Detect library. Please download the Mobile Detect library from their website, or pull it directly into your project folder using Composer with composer require mobiledetect/mobiledetectlib.

WHAT IS THE USER AGENT?

Let me just do a quick quote from Mozilla developer:

The User-Agent request header contains a characteristic string that allows the network protocol peers to identify the application type, operating system, software vendor or software version of the requesting software user agent.

In the more layman terms, the HTTP user-agent is “invisible information” that a web browser sends to the web server when requesting for a web page – We, the web developers can then use this information to determine what kind of technology the user has, and serve our webpages accordingly.

WHAT INFORMATION IS IN THE USER AGENT?

Quoting from good old Mozilla again, here is how a typical user-agent is formatted:

User-Agent: Mozilla/<version> (<system-information>) <platform> (<platform-details>) <extensions>

A more realistic example from my very own computer:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.119 Safari/537.36

If you are interested, you can also check your own user-agent at whatismybrowser.com, and here are the more relevant examples of mobile agents:

• Android user agents
• iOS user agents

Some of you sharp code ninja should have already figured out how we can determine if the user is on a mobile or desktop device now – The hardware type of mobile devices almost always reports as Mobile, Mobile – Phone, or Mobile – Tablet.

DETECTION WITH USER-AGENT

The user-agent can be accessed from the $_SERVER['HTTP_USER_AGENT'] global variable – PHP server variable, and we can use it to detect the platform.

<?php
function isMobile () {
  return is_numeric(strpos(strtolower($_SERVER['HTTP_USER_AGENT']), "mobile"));
}

echo isMobile() ? "You are using a mobile device." : "You are on a desktop or laptop." ;
/* If you are redirecting the user to a mobile page, it is as simple as
if (isMobile()) {
  header("Location: http://mobile.yoursite.com/");
} */
?>

It’s that simple – As long as the user-agent string contains the word “mobile”, we will consider that the user is on a mobile device.

MORE CHECKS

<?php
function checkDevice() {
// checkDevice() : checks if user device is phone, tablet, or desktop
// RETURNS 0 for desktop, 1 for mobile, 2 for tablets

  if (is_numeric(strpos(strtolower($_SERVER['HTTP_USER_AGENT']), "mobile"))) {
    return is_numeric(strpos(strtolower($_SERVER['HTTP_USER_AGENT']), "tablet")) ? 2 : 1 ;
  } else {
    return 0;
  }
}

$deviceType = checkDevice();
if ($deviceType==0) {
  echo "DESKTOP";
} else if ($deviceType==1) {
  echo "PHONE OR MOBILE";
} else {
  echo "TABLET";
}
?>

Yep, we simply add another layer of check to our earlier function, and this will further filter out the tablets.

GETTING THE MOBILE DETECT LIBRARY

You can download the Mobile Detect library from their website, or pull it directly into your project folder using Composer with composer require mobiledetect/mobiledetectlib:

D:\http\test>composer require mobiledetect/mobiledetectlib
Using version ^2.8 for mobiledetect/mobiledetectlib
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 1 install, 0 updates, 0 removals
  - Installing mobiledetect/mobiledetectlib (2.8.33): Downloading (100%)
Writing lock file
Generating autoload files

THE MOBILE DETECT SCRIPT

Once you have downloaded the mobile detect script, all that is left is to use it:

<?php
// INCLUDE MOBILE DETECT LIBRARY
require "mobile-detect/Mobile_Detect.php";
$detect = new Mobile_Detect;

// DETECTION ENGINE
if ($detect->isMobile() || $detect->isTablet()) {
  echo "MOBILE OR TABLET DEVICE";
  if( $detect->isiOS() ){
    echo "IOS";
  }
  if( $detect->isAndroidOS() ){
    echo "ANDROID";
  }
} else {
  echo "DESKTOP";
}

// There are plenty more, and you check it out here -
// http://demo.mobiledetect.net/
?>

WHICH IS THE BEST?

Personally, I prefer the first lightweight solution – Clean, simple, fast, and it is good enough to cover most cases. But if you really have to dig in deep and separate your users down to the brand or browser… Then it is a good time to reconsider how you are approaching your project design.

THE LIMITATIONS

We can only get so much information out of the user agent. Please also take note that the detection is not going to be 100% accurate, as changes will occur over time – We literally have folding smartphones that are in-between a tablet and phone, also tablets that act as laptops… So which is which? You decide.

P.S. The advanced users can also choose to disable the user agent, and this detection feature is going to fail.

ALTERNATIVE – RESPONSIVE DESIGN

Sometimes, all it takes is to just adopt a responsive design and change the HTML/CSS. Yep, if the design is your only concern, then is it really worth the time and money to develop another dedicated mobile site? You decide.

[출처] https://code-boxx.com/detect-mobile-desktop-in-php