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Introducing Dependency Management and Composer
7:02The most effective developers are the ones who know what code to write and what code to use. These external "packages" of code are called dependencies, because your application depends on them. Composer is a tool to help you manage which packages, and which package versions, your application depends upon.
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Hi Alena here, the most effective
developers are the ones who know what
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code to write and what code to use.
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When you're able to use code that others
have written, you're able to spend more
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time writing code that you
need to your own application.
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These external packages of
code are called dependencies,
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because your application depends on them.
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Composer is a tool,
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that manages which version of these
dependencies are required to be installed.
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Composer installs those packages
by downloading them into a folder
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within your project.
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You can then use composers
autoload functionality
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to include those dependencies
on an as needed basis.
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Before we get any further
into how composer works.
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Let's jump into work spaces and
see how we can make composer work for us.
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We could just download the code into our
project and include it when we want.
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But let's use composer to
help a stay organized.
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I'm going to set up, a simple
application for sending HTML email.
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The first thing I want to use,
is the third party library or
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package called phpmailer.
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In the console,
we type composer require and then enter.
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Next, you'll be asked to search for
a package.
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In this case, we'll be using phpmailer.
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Next, composer will list
suggested packages.
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Each package listed is
prefixed with the vendor name.
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Some vendors have multiple packages and
this allows for
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grouping and organizing those packages.
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The first one is the one we want,
phpmailer/phpmailer.
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So we type zero and then enter again.
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Composer then asks for
the version constraint.
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We'll go over versioning in
more detail a little later.
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For now, just leave it blank for
the latest version and press enter.
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We could add another
package at this point.
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We just press enter again
to finish the setup.
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Let's clear this screen and
refresh our files.
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We can now see composer.json.
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We can then run composer install, And
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composer will grab the required packages
and place the files in a vendor folder.
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Some dependencies have
their own dependencies.
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For example, phpunit for
unit testing has many dependencies.
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Making it a robust tool with less for
the maintainers to worry about.
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However phpmailer doesn't have
any of its own dependencies, so
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you won't see any here.
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If we Refresh the files.
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You will see an autoload file and
a composer folder.
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We'll jump back to
autoloading in just a minute,
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phpmailer has a suggestion for you.
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If you want to use Google authentication,
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you want to install the package
league/auth2-google.
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The vendor of this package league refers
to The League of Extraordinary Packages.
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This is a group of developers,
who have banded together to build solid
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well tested php packages using
modern coding standards.
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They have a wide range of packages for
such things as Mongodb,
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templating, JSON, markdown and
NGO related tasks.
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The league holds each other accountable
for using standards and best practices, so
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it's a good place to look for packages.
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If we want to follow the suggestion we
can simply type, composer require and
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the full package,
which is league/oauth2-google.
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We can also add a version constraint
as well, if we wanted to or just enter.
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After using the require command, the added
requirements should be installed.
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If this doesn't happen or
if you make additions or updates manually,
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you'll need to run
the composer update command.
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If you don't want to update all your
packages but only a specific package,
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you can specify that package after update.
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This time oauth2 requires
some additional packages.
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So composer installs
those packages as well.
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Great.
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We can already see some of
the benefits composer gives us.
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We didn't have to download all
those packages individually.
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So, now how do we use those packages?
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Let's close the console.
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I told you that we get
back to autoloading.
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Autoloading, allows us
to include a single file
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which will then automatically load
the classes when they're needed.
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We use require the magic constant __DIR,
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Then vendor, Autoload, .php.
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Composer will then load the vendor
files but only when needed.
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Since we're only using
phpmailer in our email file.
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Composer will only load that
package on our email page, and
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the phpmailer classes referenced.
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It will not load the phpmailer
class on any of the other pages or
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we might include the autoloader.
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I've already included the code needed
to make phpmailer work in work spaces.
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So we can preview the site in a browser.
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Choose new email and fill out the form.
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You'll see that the new email
now appears on the home page.
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We can go back to the work spaces
console and verify the email.
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Type mail and
you'll see the email we've just sent.
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Type 1 and
then we can see the details of the email.
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Type exit to close the email.
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And then we can close the console.
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