HTTP and the Web

In building a web application with the Pop PHP Framework, there are a few concepts and components with which you’ll need to be familiar. Along with the core components, one would commonly leverage the popphp/pop-http and popphp/pop-web components to get started on building a web application with Pop PHP.

HTTP

The popphp/pop-http component contains a request object and a response object that can assist in capturing and managing the incoming requests to your application and handle assembling the appropriate response back to the user.

Requests

The main request class is Pop\Http\Request. It has a robust API to allow you to interact with the incoming request and extract data from it. If you pass nothing to the constructor a new request object, it will attempt to parse the value contained in $_SERVER['REQUEST_URI']. You can, however, pass it a $uri to force a specific request, and also a $basePath to let the request object know that the base of the application is contained in a sub-folder under the document root.

Creating a new request object with a base path

In the following example, let’s assume our application is in a sub-folder under the main document root:

  • /httpdocs
  • /httpdocs/system
  • /httpdocs/system/index.php

We create a request object and pass it the base path /system so that application knows to parse incoming request after the /system base path.

$request = new Pop\Http\Request(null, '/system');

For example, if a request of /system/users came in, the application would know to use /users as the request and route it accordingly. If you need to reference the request URI, there are a couple of different methods to do so:

  • $request->getBasePath(); - returns only the base path (‘/system’)
  • $request->getRequestUri(); - returns only the request URI (‘/users’)
  • $request->getFullRequestUri(); - returns the full request URI string (‘/system/users’)

Getting path segments

If you need to break apart a URI into its segments access them for your application, you can do it with the getPath() method. Consider the URI /users/edit/1001:

  • $request->getPath(0); - returns ‘users’
  • $request->getPath(1); - returns ‘edit’
  • $request->getPath(2); - returns ‘1001’
  • $request->getPath(); - returns an array containing all of the path segments

Test the HTTP Method

  • $request->isGet();
  • $request->isHead();
  • $request->isPost();
  • $request->isPut();
  • $request->isPatch();
  • $request->isDelete();
  • $request->isTrace();
  • $request->isHead();
  • $request->isOptions();
  • $request->isConnect();

Retrieve Data from the Request

  • $request->getQuery($key = null);
  • $request->getPost($key = null);
  • $request->getFiles($key = null);
  • $request->getPut($key = null);
  • $request->getPatch($key = null);
  • $request->getDelete($key = null);
  • $request->getServer($key = null);
  • $request->getEnv($key = null);

If you do not pass the $key parameter in the above methods, the full array of values will be returned. The results from the getQuery(), getPost() and getFiles() methods mirror what is contained in the $_GET, $_POST and $_FILES global arrays, respectively. The getServer() and getEnv() methods mirror the $_SERVER and $_ENV global arrays, respectively.

If the request method passed is PUT, PATCH or DELETE, the request object will attempt to parse the raw request data to provide the data from that. The request object will also attempt to be content-aware and parse JSON or XML from the data if it successfully detects a content type from the request.

If you need to access the raw request data or the parsed request data, you can do so with these methods:

  • $request->getRawData();
  • $request->getParsedData();

Retrieve Request Headers

  • $request->getHeader($key); - return a single request header value
  • $request->getHeaders(); - return all header values in an array

Responses

The Pop\Http\Response class has a full-featured API that allows you to create a outbound response to send back to the user or parse an inbound response from a request. The main constructor of the response object accepts a configuration array with the basic data to get the response object started:

$response = new Pop\Http\Response([
    'code'    => 200,
    'message' => 'OK',
    'version' => '1.1',
    'body'    => 'Some body content',
    'headers' => [
        'Content-Type' => 'text/plain'
    ]
]);

All of that basic response data can also be set as needed through the API:

  • $response->setCode($code); - set the response code
  • $response->setMessage($message); - set the response message
  • $response->setVersion($version); - set the response version
  • $response->setBody($body); - set the response body
  • $response->setHeader($name, $value); - set a response header
  • $response->setHeaders($headers); - set response headers from an array

And retrieved as well:

  • $response->getCode(); - get the response code
  • $response->getMessage(); - get the response message
  • $response->getVersion(); - get the response version
  • $response->getBody(); - get the response body
  • $response->getHeader($name); - get a response header
  • $response->getHeaders($headers); - get response headers as an array
  • $response->getHeadersAsString(); - get response headers as a string

Check the Response

  • $response->isSuccess(); - 100, 200 or 300 level response code
  • $response->isRedirect(); - 300 level response code
  • $response->isError(); - 400 or 500 level response code
  • $response->isClientError(); - 400 level response code
  • $response->isServerError(); - 500 level response code

And you can get the appropriate response message from the code like this:

use Pop\Http\Response;

$response = new Response();
$response->setCode(403);
$response->setMessage(Response::getMessageFromCode(403)); // Sets 'Forbidden'

Sending the Response

$response = new Pop\Http\Response([
    'code'    => 200,
    'message' => 'OK',
    'version' => '1.1',
    'body'    => 'Some body content',
    'headers' => [
        'Content-Type'   => 'text/plain'
    ]
]);

$response->setHeader('Content-Length', strlen($response->getBody()));
$response->send();

The above example would produce something like:

HTTP/1.1 200 OK
Content-Type: text/plain
Content-Length: 19

Some body content

Redirecting a Response

Pop\Http\Response::redirect('http://www.domain.com/some-new-page');
exit();

Parsing a Response

In parsing a response from a request, you pass either the URL or a response string that already exists. A new response object with all of its data parsed from that response will be created:

$response = Pop\Http\Response::parse('http://www.domain.com/some-page');

if ($response->getCode() == 200) {
    // Do something with the response
} else if ($response->isError()) {
    // Uh oh. Something went wrong
}

Web Components

The popphp/pop-web component has a few useful sub-components that come with it. The two most commonly used would be the session and cookie sub-components.

Sessions

The session sub-component gives you multiple ways to interact with the $_SESSION variable and store and retrieve data to it. The following are supported:

  • Managing basic sessions and session values
  • Creating namespaced sessions
  • Setting session value expirations
  • Setting request-based session values

Basic Sessions

$sess = Pop\Web\Session::getInstance();
$sess->user_id    = 1001;
$sess['username'] = 'admin';

The above snippet saves values to the user’s session. To recall it later, you can access the session like this:

$sess = Pop\Web\Session::getInstance();
echo $sess->user_id;    // echos out 1001
echo $sess['username']; // echos out 'admin'

And to destroy the session and its values, you can call the kill() method:

$sess = Pop\Web\Session::getInstance();
$sess->kill();

Namespaced Sessions

Namespaced sessions allow you to store session under a namespace to protect and preserve that data away from the normal session data.

$sessFoo = new Pop\Web\SessionNamespace('foo');
$sessFoo->bar = 'baz'

What’s happening “under the hood” is that an array is being created with the key foo in the main $_SESSION variable and any data that is saved or recalled by the foo namespaced session object will be stored in that array.

$sessFoo = new Pop\Web\SessionNamespace('foo');
echo $sessFoo->bar; // echos out 'baz'

$sess = Pop\Web\Session::getInstance();
echo $sess->bar; // echos out null, because it was only stored in the namespaced session

And you can unset a value under a session namespace like this:

$sessFoo = new Pop\Web\SessionNamespace('foo');
unset($sessFoo->bar);

Session Value Expirations

Both basic sessions and namespaced sessions support timed values used to “expire” a value stored in session.

$sess = Pop\Web\Session::getInstance();
$sess->setTimedValue('foo', 'bar', 60);

The above example will set the value for foo with an expiration of 60 seconds. That means that if another request is made after 60 seconds, foo will no longer be available in session.

Request-Based Session Values

Request-based session values can be stored as well, which sets a number of time, or “hops”, that a value is available in session. This is useful for flash messaging. Both basic sessions and namespaced sessions support request-based session values.

$sess = Pop\Web\Session::getInstance();
$sess->setRequestValue('foo', 'bar', 3);

The above example will allow the value for foo to be available to the user for 3 requests. After the 3rd request, foo will no longer be available in session. The default value of “hops” is 1.

Cookies

The cookie sub-component allows you to interact with and manage cookies within the user’s session. When you create a new instance of a cookie object, you can pass it some optional parameters for more control:

$cookie = Pop\Web\Cookie::getInstance([
    'expire'   => 300,
    'path'     => '/system',
    'domain'   => 'www.domain.com',
    'secure'   => true,
    'httponly' => true
]);

These are all options that give you further control over when a cookie value expires and where and how it is available to the user. From there, you can store and retrieve cookie values like this:

$cookie->foo   = 'bar';
$cookie['baz'] = 123;

echo $cookie->foo;   // echos 'bar'
echo $cookie['baz']; // echos 123

And then you can delete a cookie value like this:

$cookie->delete('foo');
unset($cookie['baz']);