Php check if package installed

How to make your PHP application check for its dependencies

The phpinfo() function displays just about everything you want to know about your PHP installation. It includes info on all your PECL and PEAR modules so it is a quick way to check what’s installed. It will also tell you useful web server information including any query strings you pass. To display all this good info just point your browser at a page on your server that contains the following code:

Automatic dependency checking

The phpinfo() function will give us a page that displays a lot of info. You can pass it bitwise constants to narrow down the information displayed but what if we want to check for specific items?

In my humble opinion, when developing software or anything in general, it is a good idea to design things so that the end user will not even need a manual because the user interface is obvious. When something doesn’t work, it should be equally obvious how to fix it.

If you write a PHP application that others will install and use, it is a good idea to check for dependencies when they try to use the application. This way even if they don’t read your documentation they will quickly know why the software is not working.

Using phpversion(), PHP_VERSION, and version_compare() to check the PHP verson

To get the core PHP version you can use either of the following methods:

 echo phpversion(); echo "
or
"; echo PHP_VERSION; ?>

The above code should output something like this:

If you are using Ubunto or some other distribution, you will note that some additional stuff is tack on to the version number (I.e. “-2ubuntu4”). This makes a comparison to your expected version a little tricky but you can use a substr()/strpos() combo to get what you need. There is an easier way to do the comparison though. The version_compare() function is “PHP-standardized” version aware. So we can do something like this:

 if (version_compare(PHP_VERSION, '5.0.0', ')) { echo 'You are using PHP version ' . PHP_VERSION . 'This program requires PHP version 5.0.0 or higher.'; } else { echo 'You are using PHP 5.0.0 or higher. You are all set!'; } ?>

Now you can check the PHP version and notify the user if it is not the minimum required version.

The PHP function documentation for each function at www.php.net include the PHP versions that contain the function in the upper left hand corner:

You can use this to learn what versions of PHP include the functions you are using in your code to help identify your minimum PHP version requirement.

Using get_loaded_extensions() to check for extensions

The get_loaded_extensions() function will return an array of PHP extensions that you can use to check if a specific extension is installed. Use it in combination with with the in_array() function to check if the extension you require is loaded. In this example I check if the PECL_HTTP module is installed:

 if (in_array("http",get_loaded_extensions())){ echo 'The PECL_HTTP module is installed. '. 'You are all set!'; } else { echo 'The PECL_HTTP module is not installed. '. 'Please install it.'; } ?>

You can use the phpversion() function to check if extension is listed and if so, its version. This code example not only checks if the PECL_HTTP module is installed, but also checks it’s version:

 if (!phpversion('http')){ echo 'The PECL_HTTP module is not installed. '. 'Please download it from '. 'here '. ' and install it.'; } else { if (version_compare(phpversion('http'),'1.6.0','>=')){ echo 'The PECL_HTTP extension is installed and '. 'version 1.6.0 or higher. You are all set!'; } else { echo 'Please upgrade your PECL_HTTP extension to '. 'version 1.6.0 or higher. You can download it '. 'here'. '.'; } } ?>

Use function_exists() to check for individual functions

So far the methods for checking dependencies have been somewhat broad. They check that the script has a certain version of PHP or extensions installed and that will likely be good enough in most cases. If you really want to be thorough you can also check if specific functions are available using the function_exists() method. In this example I check that the http_request() module, which is part of the PECL_HTTP extension, is there before I use it. If it is not, I use the less featured, built in, file_get_contents() function.

 if (function_exists("http_get")) { echo 'Using the http_get():
' . http_parse_message(http_get("http://www.example.com"))->body; } else { echo 'Using the file_get_contents():
' . file_get_contents("http://www.example.com"); } ?>

Check for include files

Here is a simple way to check for include files. It doesn’t verify their content but you can at least make sure they are there:

 if (!file_exists('httptest.php')){ die('The httptest.php include file is missing.'); } else { require_once('httptest.php'); } ?>

Wrap up

Checking dependencies is an important part of building robust software and hopefully the above techniques will help accomplish that. Even if your end user is a very technical they will likely appreciate a good dependency checking mechanism that quickly tells them whats missing to save them time. If your software will be used by non-technical users you might want to automatically and gracefully downgrade your software feature set instead of generating errors and asking them for something they won’t know how to do. Usability is king!

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How to Check If a PHP Extension is Installed via Command Line

Learn how to check if a PHP extension is installed or loaded via command line and troubleshoot issues with basic extension management practices.

PHP extensions are essential components for web development. They add functionality to the core PHP language and allow developers to use additional features that are not included in the base PHP installation. It’s important to know how to check if an extension is installed or loaded to troubleshoot issues. In this guide, we will walk through how to check installed PHP extensions via command line, see the loaded extensions and basic PHP extension management best practices.

Checking Installed PHP Extensions via Command Line

To check Installed PHP Extensions via command line, make sure php5-cli is installed and run the following command:

This will return a list of all installed extensions. If the php5-cli package is not installed, you can install it on Ubuntu using

sudo apt-get install php5-cli 

You can also specify a PHP version by adding it to the command:

If you want to check if a specific extension is installed, use

Seeing the Loaded Extensions

To see the loaded extensions, use the phpinfo() function. Create a text file with the following content:

Save it as “version.php” and open it in a web browser. This will display a lot of information about your PHP installation, including a list of all the loaded extensions. You can also use the -m switch with the CLI version of PHP to see the loaded extensions:

PHP Extension Management

PHP extensions can be installed by compiling and installing from source or using a package manager. Best practices for PHP extension management include regularly updating and removing unused extensions.

Compiling and installing from source is a more advanced method and requires knowledge of the build process. Using a package manager, such as apt-get, yum, or Homebrew, simplifies the installation process. To remove an extension, delete the extension file and restart the web server.

Common Issues with PHP Extensions

common issues with php extensions include compatibility problems with different versions of PHP and conflicts with other extensions. Troubleshooting these issues involves checking for conflicting extensions and updating to the latest version of PHP.

Troubleshooting can also involve checking the PHP error log for any related errors. The dl() function can be used to dynamically load a PHP extension at runtime, but it is not recommended due to security risks.

Other PHP code samples that may be helpful for checking if a PHP extension is installed or loaded include the use of the function extension_loaded() and the command php-config —extension-dir

In Php , for instance, php check if extension is installed code sample

Conclusion

Checking if a PHP extension is installed or loaded is an essential skill for web developers. By using the command line and phpinfo() function, you can easily check for installed and loaded extensions. Basic PHP extension management best practices and troubleshooting tips can help avoid common issues and optimize performance.

Frequently Asked Questions — FAQs

What are PHP extensions and why are they important?

PHP extensions are additional features or libraries that can be added to a PHP installation to provide additional functionality for web development. They are important because they can enhance the performance and capabilities of a PHP application.

How do I know if a PHP extension is installed?

You can use the command line and run «php -m» to see a list of all installed extensions. To check if a specific extension is installed, use «php -m | grep «. You can also use the phpinfo() function to see the loaded extensions.

What are the best practices for managing PHP extensions?

Best practices for PHP extension management include regularly updating and removing unused extensions. Extensions can be installed by compiling and installing from source or using a package manager, such as apt-get, yum, or Homebrew.

What are common issues with PHP extensions?

Common issues with PHP extensions include compatibility problems with different versions of PHP and conflicts with other extensions. Troubleshooting these issues involves checking for conflicting extensions and updating to the latest version of PHP.

How can I dynamically load a PHP extension at runtime?

The dl() function can be used to dynamically load a PHP extension at runtime, but it is not recommended due to security risks.

How can I troubleshoot PHP extension issues?

Troubleshooting PHP extension issues involves checking for conflicting extensions, updating to the latest version of PHP, and checking the PHP error log for any related errors.

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Composer/PHP: How to check if composer package is installed?

ref: https://getcomposer.org/doc/03-cli.md#show Solution 4: If you only want to check version for only one, you can do Note that only installed packages are shown by default now, and installed option is now deprecated. I was expecting to find the version installed, inside composer.lock, but it’s not there: I need the version because I want to tie my library to a specific set of versions, eg: If I find the version is 1.3.5, in my composer.json I would like to put something like this: Any ideas?

Composer/PHP: How to check if composer package is installed?

What is the cleanest way to check whether a package (of any version) is installed/present, using PHP within our application?

Basically, inside our application we want to call a function with the following signature:

bool function hasComposerPackage(string $packageName)

What would this function have to contain so that we can do something like:

if (hasComposerPackage('phpunit/phpunit'))

Ideally this needs to happen without any command-line exec calls and it should not autoload any unnecessary files in the process.

Edit: Composer 2 now supports this! https://blog.packagist.com/composer-2-0-is-now-available/

There is a new class, Composer\InstalledVersions, which is autoloaded in every project and is available at runtime. It allows you to check which packages/versions are present at runtime of your own project.

@user1132363 using shell_exec() to run something like composer show is the only way to know for sure, but you seem to refuse to want to go this route. I’m not sure why you refuse, this is the solution to your problem. There is no other reliable means. Using class_exists is also unreliable as class names can change in packages.

That said, I think there’s a bigger question here that you aren’t asking: What problem are you actually trying to solve? As in, why do you need to check to see if a package is installed?

Get the list of outdated Composer packages, Since Composer v1.1 (May 2016) the following commands are available: composer outdated shows you the list of outdated packages. composer show -l returns the complete list of packages. packages in need of update are colored red. the (still) up-2-date ones are colored green. both commands accept …

How to

How to check the composer is installed or not ?

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