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Along with "Magic Methods", PHP also provides a large number of predefined constants to give us... a little more magic. These "Magic Constants" can provide details about our script and our environment. We'll look at a few "Magic Constants" that help us understand our classes and objects.
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Magic methods can be a lot of fun,
as well as extremely powerful.
0:00
But PHP gives us even more magic
in the form of magic constants.
0:05
PHP provides a large number of predefined
constants to give us a little more magic.
0:10
These special constants both start and
end with double underscores, and
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are not case sensitive.
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But, if we start changing
the case all over the place,
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it makes things very difficult to read.
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You should write all
constants in uppercase.
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Magic constants can provide
a lot of information.
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Let's take a look at a few of the most
useful in relation to objects.
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Let's modify the to string method.
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Instead of only displaying
the recipe title,
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let's give it a bit more information
about the object itself.
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The first magic constant
we'll use is class.
0:50
Written __CLASS__.
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This gives us the name
of the class itself.
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Let's use this in a message.
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Let's also remove our call
to the displayRecipe.
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Now let's run our script.
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Now we see that you are calling a recipe
object with the title, My First Recipe.
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Looks good so far.
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Let's add a little more magic.
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There are two constants that reference
the file where the class is stored.
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The first one is __FILE__.
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This gives us the full
path with the file name.
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We can get just the file name by combining
that with the function, basename.
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We could use the function dir
name with file as well to pull
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only the directory path.
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But we have another constant that
you'll often see the __DIR__ or
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directory constant.
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This constant gives us the full path
to the file without the file name.
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I use __DIR__ often when I
want to link to another file
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within the same directory as this file.
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It works even if this file
is included in another file.
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Let's add both of these
to our message as well.
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Next, let's show specific information
about where in the class we are currently
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looking.
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__LINE__ will tell us the current
line number in the file and
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the __METHOD__ will tell us the name
of the method we are using.
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Let's add these as well.
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Finally, let's show a list of the methods
in case the user is looking for something.
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This is another place where we use
a function in combination with
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a magic constant.
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get_class_methods.
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We then pass it the __CLASS__.
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Now let's add this to our output.
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Let's use the implode.
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When we finish,
we want to return the output.
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Now we're ready to run our script again.
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Wonderful, we have a lot of information
about our object that we can use to update
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the call to our object.
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For example,
I can look through the list of methods and
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see the exact name of my getters and
setters.
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For security purposes,
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you should not display the full
directory path on a production server.
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It can give hackers much more
information than you want.
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Let's add this toString method
to our render class as well.
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Then we'll be able to show
the methods that are available.
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Let's copy this.
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And we'll go in to render.
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We only want to say what
methods are available.
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But let's change this so it tells us
which type of object we're using.
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Now let's go back to our cookbook.
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Since we don't have an object,
we can just echo new Render.
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And now let's run our code.
6:05
Great, we see the results of
the render object as well.
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