These DocBlocks are ignored by the PHP engine, but they are very useful for us, and many tools and IDEs will read them. -The code inside the docblock is written in the PHPDoc language.

Running the code

Run php Planet.php. You should see no output - a class by itself doesn't do anything. We will write code to use this class on the next page.

What's in the class

Planet is a final class. This prevents any other classes being written as subclasses of Planet. Subclassing is beyond the scope of this tutorial, but for now we can say that it adds significant complexity, and if we don't need it we should probably avoid it. It's therefore a good practice to make classes final by default - we can always delete the -word final if we ever find we do need to make a subclasses of Planet.

@@ -94,7 +95,7 @@

Why did I write it?

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

diff --git a/02-getting-php.html b/02-getting-php.html index 2b3b997..5fc5cd3 100644 --- a/02-getting-php.html +++ b/02-getting-php.html @@ -45,6 +45,7 @@

PHP as a Second Language

@@ -92,7 +93,7 @@

Windows

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

diff --git a/03-hello-world.html b/03-hello-world.html index 29b3760..6c774a8 100644 --- a/03-hello-world.html +++ b/03-hello-world.html @@ -45,6 +45,7 @@

PHP as a Second Language

@@ -84,7 +85,7 @@

Hello, world.

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

diff --git a/04-http.html b/04-http.html index 8619fa7..03bf4f8 100644 --- a/04-http.html +++ b/04-http.html @@ -45,6 +45,7 @@

PHP as a Second Language

@@ -75,7 +76,7 @@

HTTP

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

diff --git a/05-variables.html b/05-variables.html index d25cee8..3556e4e 100644 --- a/05-variables.html +++ b/05-variables.html @@ -45,6 +45,7 @@

PHP as a Second Language

@@ -138,7 +139,7 @@

Associative arrays

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

diff --git a/06-functions.html b/06-functions.html index 2646a06..232e011 100644 --- a/06-functions.html +++ b/06-functions.html @@ -45,6 +45,7 @@

PHP as a Second Language

@@ -95,7 +96,7 @@

Functions

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

diff --git a/07-classes-1.html b/07-classes-1.html index 70db1c0..3495d30 100644 --- a/07-classes-1.html +++ b/07-classes-1.html @@ -45,6 +45,7 @@

PHP as a Second Language

@@ -162,7 +163,7 @@

What's in the class

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

diff --git a/08-classes-2.html b/08-classes-2.html index cc5ac23..536f823 100644 --- a/08-classes-2.html +++ b/08-classes-2.html @@ -45,6 +45,7 @@

PHP as a Second Language

@@ -152,7 +153,7 @@

Composer

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

diff --git a/09-classes-3.html b/09-classes-3.html index 4616dae..13ae525 100644 --- a/09-classes-3.html +++ b/09-classes-3.html @@ -45,6 +45,7 @@

PHP as a Second Language

@@ -162,7 +163,7 @@

Object Identity

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

diff --git a/10-testing.html b/10-testing.html index 9c029b5..e10b95b 100644 --- a/10-testing.html +++ b/10-testing.html @@ -45,6 +45,7 @@

PHP as a Second Language

@@ -169,7 +170,7 @@

Writing a test

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

diff --git a/11-databases.html b/11-databases.html new file mode 100644 index 0000000..57ce192 --- /dev/null +++ b/11-databases.html @@ -0,0 +1,246 @@ + + + + + + + PHP as a Second Language + + + + + + + + + + + + +

DRAFT

PHP as a Second Language

Databases

PHP applications often connect to databases. This is even harder to avoid in PHP than it would be in other languages +you can run on a web server like JS, Java, or C#, because PHP has a share-nothing architecture. That means that the +code dealing with each request runs in isolation, and does not share any objects or variables with other requests. At +the end of the request-response cycle all stack frames are unwound and all objects are garbage.

So if your program needs to persist anything from one page to the next, a database is a natural choice.

For simplicity, we will use SQLite. This is not a database server that you connect to, +but a full featured SQL database engine supplied as a C library, and available as an add-on module for PHP. An SQLite +database is just a file.

The details of SQL (structured query language), the programming language for defining and querying databases, are beyond +the scope of this tutorial. We will see some SQL code, but as far as PHP is concerned they are just strings to send to +the database engine.

Install the SQLite PHP Module

We will use our SQLite database via PHP's PHP Data Objects (PDO) extension, which provides a consistent interface for +accessing many different DB types.

First check if the necessary PHP modules are installed. Run php -i | grep sqlite. If you have the module set up, +you should see a line like "PDO drivers => sqlite". There may be other drivers listed alongside sqlite.

If you don't have the PDO SQLite module, how to install it will depend on your OS and how you installed PHP.

Linux

If you installed PHP through your package manager, there should be an SQLite module available in the same place. Make +sure you get the module that matches your PHP version number. For instance, on Debian or Ubuntu search your repository +with apt-cache search php | grep sqlite. Once you've found the package name, e.g. php7.4-sqlite3 install it with +a command such as sudo apt install php7.4-sqlite3.

Mac

If you installed PHP via homebrew, I think should automatically have come with SQLite built in and enabled.

Windows

If you installed PHP as part of XAMPP this should have SQLite enabled by default.

Creating a database

First, let's write a PHP script src/create-database.php to create a new database with one table:

<?php declare(strict_types=1);
+
+namespace PhpAsASecondLanguage;
+use PDO;
+
+$filename =__DIR__ . "/database.sqlite";
+
+file_put_contents($filename, '');
+
+$connection = new PDO("sqlite:".$filename);
+
+$connection->query('
+    CREATE TABLE planets (
+        id INTEGER PRIMARY KEY,
+        name text,
+        population_size INTEGER
+    );
+'
+);

Run the script with php create-database.php. It should create a new binary file database.sqlite.

file_put_contents writes a string to a file, creating the file if it already exist. We're using here simply to create +a completely empty file.

The PDO class is supplied by the PDO extension. A PDO object represents a connection to a database, and allows us to +send it queries and get back results. When we call the PDO constructor +we pass it a string holding details of the database we want to connect to, known as a DSN. For SQLITE the DSN +consists of sqlite: followed by the absolute file path of our database.

Querying the database

Let's write a very small program to put the planets in the database, and let us view info about any planet. First we +will need a class that can insert all the planets. Make a file src/PlanetStore.php

<?php declare(strict_types=1);
+
+namespace PhpAsASecondLanguage;
+
+use PDO;
+
+final class PlanetStore
+{
+    private PDO $connection;
+
+    public function __construct(PDO $connection) {
+        $this->connection = $connection;
+    }
+
+    public function storePlanets(): void
+    {
+        $statement = $this->connection->prepare('INSERT INTO planets (name, population_size) values (?, ?);');
+        foreach ($this->generatePlanets() as $planet) {
+            $statement->execute([$planet->getName(), $planet->getPopulationSize()]);        
+        }
+    }
+
+    /** @return Planet[] */
+    private function generatePlanets(): array
+    {
+        return [
+            new Planet('Mercury', 0),
+            new Planet('Venus', 0),
+            new Planet('Earth', 7.7 * 10**9),
+            new Planet('Mars', 0),
+            new Planet('Jupiter', 0),
+            new Planet('Saturn', 0),
+            new Planet('Uranus', 0),
+            new Planet('Neptune', 0),
+        ];
+    } 
+}

And write a script to invoke this class: storePlanets.php:

<?php declare(strict_types=1);
+
+namespace PhpAsASecondLanguage;
+
+require_once __DIR__ . '/vendor/autoload.php';
+
+use PDO;
+
+$planetStore = new PlanetStore(
+    new PDO("sqlite:". __DIR__ . '/database.sqlite')
+);
+
+$planetStore->storePlanets();

Run php storePlanets.php. This should add the eight planets to the database. If it works it won't produce any visible +output.

The most important thing to notice about our code so far is that we didn't concatenate any strings to create queries to +send to the database. Instead we prepared a query, using question marks as placeholders for our data, and then supplied +the values of those parameters separately each time we executed the query. This practice makes our database use much +less error prone and more secure. The database engine knows what exactly what's code that it should interpret and what's +data that it should simply store.

Now let's write the code to show a planet. First let's add a function to the PlanetStore class to pull a Planet out of +the database:

    public function getPlanet(string $planetName): ?Planet
+    {
+        $statement = $this->connection->prepare(
+            'SELECT name, population_size FROM planets where name = :name;'
+        );
+        $statement->bindValue(':name', $planetName);
+        $statement->execute();
+
+        $row = $statement->fetch(PDO::FETCH_ASSOC);
+
+        if (! $row) {
+            return null;
+        }
+
+        return new Planet($row['name'], (float) $row['population_size']);
+    }

Notice the return type: ?Planet means that the function may either return an instance of Planet, or the value null. +We can add ? to the beginning of any type name to make it nullable.

We use (float) to cast or convert the population size data from a string, as it comes back from the sqlite DB, to +a floating point number.

In this case we have used a named parameter in the database query, instead of a question mark.

Finally we need to make a PHP script to go between this function and the browser. Call it viewPlanet.php:

<?php declare(strict_types=1);
+
+namespace PhpAsASecondLanguage;
+
+require_once __DIR__ . '/vendor/autoload.php';
+
+use PDO;
+
+$planetStore = new PlanetStore(
+    new PDO("sqlite:". __DIR__ . '/database.sqlite')
+);
+
+$planet = $planetStore->getPlanet($_GET['name']);
+
+header('Content-Type: text/plain');
+if ($planet === null) {
+    http_response_code(404);
+    echo ('Planet not found');
+    exit();
+}
+
+echo "**********   {$planet->getName()}   **********\n\n";
+echo "Population: {$planet->getPopulationSize()}\n";

Notice the $_GET array - PHP automatically fills this so-called superglobals array with any query parameters sent by +the browser. It is available to us anywhere in our program, but it's best to limit where we use it - code that directly +pulls data from superglobals can be hard to test and re-use.

Run the PHP server:

php -S localhost:8080

Open http://localhost:8080/viewPlanet.php?name=Earth in your browser.

Other Database Engines.

PDO has drivers for eleven other database engines that you can use +use instead of SQLite. Connecting, sending queries, and receiving rows should work in the same way, but of course the +details of connection strings and SQL code will vary from DB to DB.

+ +

+ Copyright Barney Laurance 2020 +

+ + + +

+ + \ No newline at end of file diff --git a/index.html b/index.html index 01de24b..33f7ad9 100644 --- a/index.html +++ b/index.html @@ -45,6 +45,7 @@

PHP as a Second Language

@@ -94,7 +95,7 @@

Why did I write it?

Site built Thu, 27 Feb 2020 22:28.

Site built Sat, 29 Feb 2020 15:37.

From c45dddd07fd8cbf091663d05c6c7099c0254c71e Mon Sep 17 00:00:00 2001 From: Circle CI Date: Sat, 29 Feb 2020 15:56:27 +0000 Subject: [PATCH 12/40] Update GH Pages based on CircleCI Build 94 [ci skip] --- 01-introduction.html | 2 +- 02-getting-php.html | 2 +- 03-hello-world.html | 2 +- 04-http.html | 2 +- 05-variables.html | 2 +- 06-functions.html | 2 +- 07-classes-1.html | 2 +- 08-classes-2.html | 2 +- 09-classes-3.html | 2 +- 10-testing.html | 2 +- 11-databases.html | 50 ++++++++++++++++++++++++-------------------- index.html | 2 +- 12 files changed, 38 insertions(+), 34 deletions(-) diff --git a/01-introduction.html b/01-introduction.html index 33f7ad9..9e9b4a6 100644 --- a/01-introduction.html +++ b/01-introduction.html @@ -95,7 +95,7 @@

Why did I write it?

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/02-getting-php.html b/02-getting-php.html index 5fc5cd3..f95accb 100644 --- a/02-getting-php.html +++ b/02-getting-php.html @@ -93,7 +93,7 @@

Windows

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/03-hello-world.html b/03-hello-world.html index 6c774a8..b3d1dc6 100644 --- a/03-hello-world.html +++ b/03-hello-world.html @@ -85,7 +85,7 @@

Hello, world.

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/04-http.html b/04-http.html index 03bf4f8..1b3e9bb 100644 --- a/04-http.html +++ b/04-http.html @@ -76,7 +76,7 @@

HTTP

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/05-variables.html b/05-variables.html index 3556e4e..f46fdc1 100644 --- a/05-variables.html +++ b/05-variables.html @@ -139,7 +139,7 @@

Associative arrays

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/06-functions.html b/06-functions.html index 232e011..b6d1d23 100644 --- a/06-functions.html +++ b/06-functions.html @@ -96,7 +96,7 @@

Functions

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/07-classes-1.html b/07-classes-1.html index 3495d30..a67a1ae 100644 --- a/07-classes-1.html +++ b/07-classes-1.html @@ -163,7 +163,7 @@

What's in the class

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/08-classes-2.html b/08-classes-2.html index 536f823..4f806c4 100644 --- a/08-classes-2.html +++ b/08-classes-2.html @@ -153,7 +153,7 @@

Composer

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/09-classes-3.html b/09-classes-3.html index 13ae525..19173ca 100644 --- a/09-classes-3.html +++ b/09-classes-3.html @@ -163,7 +163,7 @@

Object Identity

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/10-testing.html b/10-testing.html index e10b95b..6b91e67 100644 --- a/10-testing.html +++ b/10-testing.html @@ -170,7 +170,7 @@

Writing a test

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/11-databases.html b/11-databases.html index 57ce192..fa4fa50 100644 --- a/11-databases.html +++ b/11-databases.html @@ -51,14 +51,14 @@

PHP as a Second Language

Databases

PHP applications often connect to databases. This is even harder to avoid in PHP than it would be in other languages -you can run on a web server like JS, Java, or C#, because PHP has a share-nothing architecture. That means that the +you can run on a web server like JS, Java, or C#, because PHP has a shared-nothing architecture. That means that the code dealing with each request runs in isolation, and does not share any objects or variables with other requests. At -the end of the request-response cycle all stack frames are unwound and all objects are garbage.

+the end of the request-response cycle all stack frames are unwound and all objects become garbage.

So if your program needs to persist anything from one page to the next, a database is a natural choice.

For simplicity, we will use SQLite. This is not a database server that you connect to, -but a full featured SQL database engine supplied as a C library, and available as an add-on module for PHP. An SQLite -database is just a file.

The details of SQL (structured query language), the programming language for defining and querying databases, are beyond +but a full featured SQL database engine supplied as a C library, and available as an add-on module for PHP, and the +world's most widely deployed DB engine. An SQLite database is just a file.

The details of SQL, the programming language for defining and querying databases, are beyond the scope of this tutorial. We will see some SQL code, but as far as PHP is concerned they are just strings to send to the database engine.

Install the SQLite PHP Module

@@ -70,10 +70,12 @@

Install the SQLite PHP Module

Linux

If you installed PHP through your package manager, there should be an SQLite module available in the same place. Make sure you get the module that matches your PHP version number. For instance, on Debian or Ubuntu search your repository -with apt-cache search php | grep sqlite. Once you've found the package name, e.g. php7.4-sqlite3 install it with -a command such as sudo apt install php7.4-sqlite3.

+with:

apt-cache search php | grep sqlite

Once you've found the package name, e.g. php7.4-sqlite3 install it with a command such as

sudo apt install php7.4-sqlite3.

Mac

If you installed PHP via homebrew, I think should automatically have come with SQLite built in and enabled.

If you installed PHP via homebrew, I think will automatically have come with SQLite built in and enabled.

Windows

If you installed PHP as part of XAMPP this should have SQLite enabled by default.

Creating a database

@@ -81,13 +83,14 @@

Creating a database

<?php declare(strict_types=1);
 
 namespace PhpAsASecondLanguage;
+
 use PDO;
 
 $filename =__DIR__ . "/database.sqlite";
 
 file_put_contents($filename, '');
 
-$connection = new PDO("sqlite:".$filename);
+$connection = new PDO("sqlite:" . $filename);
 
 $connection->query('
     CREATE TABLE planets (
@@ -98,12 +101,13 @@ Creating a database
 '
 );

Run the script with php create-database.php. It should create a new binary file database.sqlite.

file_put_contents writes a string to a file, creating the file if it already exist. We're using here simply to create +

file_put_contents writes a string to a file, overwriting the file if it already exists. We're using here to create a completely empty file.

The PDO class is supplied by the PDO extension. A PDO object represents a connection to a database, and allows us to -send it queries and get back results. When we call the PDO constructor -we pass it a string holding details of the database we want to connect to, known as a DSN. For SQLITE the DSN -consists of sqlite: followed by the absolute file path of our database.

The PDO class is supplied by the PDO extension. A PDO object represents +a connection to a database, and allows us to send it queries and get back results. When we call the +PDO constructor we pass it a string holding details of the database +we want to connect to, known as a Data Source Name or DSN. For SQLite the DSN consists of 'sqlite:' followed by an +absolute file path.

Querying the database

Let's write a very small program to put the planets in the database, and let us view info about any planet. First we will need a class that can insert all the planets. Make a file src/PlanetStore.php

@@ -144,7 +148,8 @@

Querying the database

]; } } -

And write a script to invoke this class: storePlanets.php:

Once again if you don't have PHP 7.4 you will need to remove the PDO property type on the $connection property.

Now write a script storePlanets.php to use this class:

<?php declare(strict_types=1);
 
 namespace PhpAsASecondLanguage;
@@ -158,13 +163,12 @@ Querying the database
 );
 
 $planetStore->storePlanets();

Run php storePlanets.php. This should add the eight planets to the database. If it works it won't produce any visible -output.

Run php storePlanets.php. This should add the eight planets to the database. It shouldn't produce any visible output.

The most important thing to notice about our code so far is that we didn't concatenate any strings to create queries to send to the database. Instead we prepared a query, using question marks as placeholders for our data, and then supplied -the values of those parameters separately each time we executed the query. This practice makes our database use much -less error prone and more secure. The database engine knows what exactly what's code that it should interpret and what's -data that it should simply store.

+the values of those parameters separately each time we executed the query.

This practice makes our database use much less error prone and more secure. The database engine knows what exactly +what's code that it should interpret and what's data that it should simply store.

Now let's write the code to show a planet. First let's add a function to the PlanetStore class to pull a Planet out of the database:

    public function getPlanet(string $planetName): ?Planet
@@ -212,9 +216,9 @@ Querying the database
 
 echo "**********   {$planet->getName()}   **********\n\n";
 echo "Population: {$planet->getPopulationSize()}\n";

Notice the $_GET array - PHP automatically fills this so-called superglobals array with any query parameters sent by +

Notice the $_GET array - PHP automatically fills this so-called superglobal array with any query parameters sent by the browser. It is available to us anywhere in our program, but it's best to limit where we use it - code that directly -pulls data from superglobals can be hard to test and re-use.

+pulls data from superglobals can be very hard to test and re-use and understand.

Run the PHP server:

php -S localhost:8080

Open http://localhost:8080/viewPlanet.php?name=Earth in your browser.

@@ -237,7 +241,7 @@

Other Database Engines.

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

diff --git a/index.html b/index.html index 33f7ad9..9e9b4a6 100644 --- a/index.html +++ b/index.html @@ -95,7 +95,7 @@

Why did I write it?

Site built Sat, 29 Feb 2020 15:37.

Site built Sat, 29 Feb 2020 15:55.

From 3414744a9a0e9b28d12cfb2d2747ce0addbf8df0 Mon Sep 17 00:00:00 2001 From: Circle CI Date: Sat, 29 Feb 2020 17:35:14 +0000 Subject: [PATCH 13/40] Update GH Pages based on CircleCI Build 98 [ci skip] --- 01-introduction.html | 3 +- 02-getting-php.html | 3 +- 03-hello-world.html | 3 +- 04-http.html | 3 +- 05-variables.html | 3 +- 06-functions.html | 3 +- 07-classes-1.html | 3 +- 08-classes-2.html | 3 +- 09-classes-3.html | 3 +- 10-testing.html | 3 +- 11-databases.html | 3 +- 12-templating.html | 143 +++++++++++++++++++++++++++++++++++++++++++ index.html | 3 +- 13 files changed, 167 insertions(+), 12 deletions(-) create mode 100644 12-templating.html diff --git a/01-introduction.html b/01-introduction.html index 9e9b4a6..4028a7d 100644 --- a/01-introduction.html +++ b/01-introduction.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -95,7 +96,7 @@

Why did I write it?

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/02-getting-php.html b/02-getting-php.html index f95accb..2f5875c 100644 --- a/02-getting-php.html +++ b/02-getting-php.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -93,7 +94,7 @@

Windows

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/03-hello-world.html b/03-hello-world.html index b3d1dc6..5362df0 100644 --- a/03-hello-world.html +++ b/03-hello-world.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -85,7 +86,7 @@

Hello, world.

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/04-http.html b/04-http.html index 1b3e9bb..38d8199 100644 --- a/04-http.html +++ b/04-http.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -76,7 +77,7 @@

HTTP

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/05-variables.html b/05-variables.html index f46fdc1..30c2af9 100644 --- a/05-variables.html +++ b/05-variables.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -139,7 +140,7 @@

Associative arrays

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/06-functions.html b/06-functions.html index b6d1d23..744036c 100644 --- a/06-functions.html +++ b/06-functions.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -96,7 +97,7 @@

Functions

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/07-classes-1.html b/07-classes-1.html index a67a1ae..bb86f31 100644 --- a/07-classes-1.html +++ b/07-classes-1.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -163,7 +164,7 @@

What's in the class

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/08-classes-2.html b/08-classes-2.html index 4f806c4..d5d817c 100644 --- a/08-classes-2.html +++ b/08-classes-2.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -153,7 +154,7 @@

Composer

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/09-classes-3.html b/09-classes-3.html index 19173ca..3bbb9b5 100644 --- a/09-classes-3.html +++ b/09-classes-3.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -163,7 +164,7 @@

Object Identity

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/10-testing.html b/10-testing.html index 6b91e67..abbb90b 100644 --- a/10-testing.html +++ b/10-testing.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -170,7 +171,7 @@

Writing a test

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/11-databases.html b/11-databases.html index fa4fa50..f8743fa 100644 --- a/11-databases.html +++ b/11-databases.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -241,7 +242,7 @@

Other Database Engines.

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

diff --git a/12-templating.html b/12-templating.html new file mode 100644 index 0000000..6ec769e --- /dev/null +++ b/12-templating.html @@ -0,0 +1,143 @@ + + + + + + + PHP as a Second Language + + + + + + + + + + + + +

DRAFT

PHP as a Second Language

Templating

Our planet viewer works, but it isn't pretty. Let's use some HTML to make it look a little better.

It has been a common practice to use PHP as a templating language, and even mix PHP and HTML code together in the same +file. While PHP can still be used as a templating language, it isn't a good one, so we won't do that.

Instead, we will use PHP to prepare whatever data we want to show, and then pass that to a template written in a +different language.

There are dozens of template engines available as libraries to use in PHP programs, and another good option +is to make a single page application, with all templating done in the browser, and data sent from the server as JSON.

Twig

For this tutorial we will write a template in the Twig language, which works with PHP.

First install Twig in your project by running:

composer require "twig/twig:^3.0"

Now let's make our template. Start by writing a page in HTML. For now we'll hard code everything. Make a +'templates' directory, and save the following as 'templates/planet.html.twig':

<!doctype html>
+<html>
+    <head>
+        <title>Some Planet</title>
+    </head>
+    <body>
+        <h1>Some Planet</h1>
+        <p>Population: 34601</p>
+    </body>
+</html>

Edit our viewPlanet.php file to make it use this template:

<?php declare(strict_types=1);
+
+namespace PhpAsASecondLanguage;
+
+require_once __DIR__ . '/vendor/autoload.php';
+
+use PDO;
+use Twig\Loader\FilesystemLoader;
+
+$planetStore = new PlanetStore(
+    new PDO("sqlite:". __DIR__ . '/database.sqlite')
+);
+
+$templateLoader = new FilesystemLoader(__DIR__ . '/templates/');
+$twig = new \Twig\Environment($templateLoader);
+
+$planet = $planetStore->getPlanet($_GET['name']);
+
+header('Content-Type: text/html');
+if ($planet === null) {
+    http_response_code(404);
+    echo ('Planet not found');
+    exit();
+}
+
+$template = $twig->load('planet.html.twig');
+
+echo $template->render();

If you run the PHP server again and view your site you should see the content of the template. Of course at this point +all we're doing is serving static HTML with extra steps.

Behind the scenes the Twig engine compiles the template to a PHP class. We don't need to read the class, but this is +useful because it means we can pass PHP objects to it and use their properties and functions. Let's pass our planet +object to the template. Change the last line of 'viewPlanet.php' to:

echo $template->render(['planet' => $planet]);

Finally we need to edit 'planet.html.twig'. Since we won't always be reading the template at the same time as the PHP file +that uses it, and neither will any tools and IDEs we might be using, we should add a comment to make it clear that we +expect to have a planet variable, and it will be of type Planet. Add the following to the top of the file:

{#  @var planet PhpAsASecondLanguage\Planet #}

In Twig we use double curly brackets to output dynamic data: Replace Some Planet with +{{planet.name}}, and replace 34601 with {{planet.populationSize}}. Twig knows that we mean getName and +getPopulationSize, so we don't have to write those function names out in full.

If you reload the page you should now see the planet details in their proper places.

Twig is a full featured special purpose programming language, with features like loops, conditionals, filters, +inheritance, etc, but this is a PHP tutorial, not a Twig tutorial.

+ +

+ Copyright Barney Laurance 2020 +

+ + + +

+ + \ No newline at end of file diff --git a/index.html b/index.html index 9e9b4a6..4028a7d 100644 --- a/index.html +++ b/index.html @@ -46,6 +46,7 @@

PHP as a Second Language

@@ -95,7 +96,7 @@

Why did I write it?

Site built Sat, 29 Feb 2020 15:55.

Site built Sat, 29 Feb 2020 17:35.

From 55490402eb613266cb099aecbef7eb67e2eeea87 Mon Sep 17 00:00:00 2001 From: Circle CI Date: Sat, 29 Feb 2020 17:47:31 +0000 Subject: [PATCH 14/40] Update GH Pages based on CircleCI Build 101 [ci skip] --- 01-introduction.html | 2 +- 02-getting-php.html | 2 +- 03-hello-world.html | 2 +- 04-http.html | 2 +- 05-variables.html | 2 +- 06-functions.html | 2 +- 07-classes-1.html | 2 +- 08-classes-2.html | 2 +- 09-classes-3.html | 2 +- 10-testing.html | 2 +- 11-databases.html | 2 +- 12-templating.html | 2 +- index.html | 2 +- 13 files changed, 13 insertions(+), 13 deletions(-) diff --git a/01-introduction.html b/01-introduction.html index 4028a7d..b1507ea 100644 --- a/01-introduction.html +++ b/01-introduction.html @@ -96,7 +96,7 @@