Sections

Response Component


Returning Responses

Part of the HTTP cycle is returning responses to clients. Phalcon\Http\Response is the Phalcon component designed to achieve this task. HTTP responses are usually composed by headers and body. The following is an example of basic usage:

<?php

use Phalcon\Http\Response;

// Responseインスタンスの取得
$response = new Response();

// ステータスコードの設定
$response->setStatusCode(404, 'Not Found');

// レスポンスの内容の設定
$response->setContent("Sorry, the page doesn't exist");

// クライアントにレスポンスを送信
$response->send();

If you are using the full MVC stack there is no need to create responses manually. However, if you need to return a response directly from a controller’s action follow this example:

<?php

use Phalcon\Http\Response;
use Phalcon\Mvc\Controller;

class FeedController extends Controller
{
    public function getAction()
    {
        // Responseインスタンスの取得
        $response = new Response();

        $feed = // ... ここでfeedをロード

        // レスポンスの内容をセット
        $response->setContent(
            $feed->asString()
        );

        // レスポンスを返す
        return $response;
    }
}

Working with Headers

Headers are an important part of the HTTP response. It contains useful information about the response state like the HTTP status, type of response and much more.

You can set headers in the following way:

<?php

// 名前でヘッダーを指定
$response->setHeader('Content-Type', 'application/pdf');
$response->setHeader('Content-Disposition', "attachment; filename='downloaded.pdf'");

// 直接ヘッダーを指定
$response->setRawHeader('HTTP/1.1 200 OK');

A Phalcon\Http\Response\Headers bag internally manages headers. This class retrieves the headers before sending it to client:

<?php

// ヘッダーバッグの取得
$headers = $response->getHeaders();

// 名前でヘッダーを取得
$contentType = $headers->get('Content-Type');

Making Redirections

With Phalcon\Http\Response you can also execute HTTP redirections:

<?php

// Redirect to the default URI
$response->redirect();

// Redirect to the local base URI
$response->redirect('posts/index');

// Redirect to an external URL
$response->redirect('https://en.wikipedia.org', true);

// Redirect specifying the HTTP status code
$response->redirect('https://www.example.com/new-location', true, 301);

All internal URIs are generated using the service (by default [Phalcon\Url](api/Phalcon_Url)). This example demonstrates how you can redirect using a route you have defined in your application:

<?php

// 名前付きルートでリダイレクト
return $response->redirect(
    [
        'for'        => 'index-lang',
        'lang'       => 'jp',
        'controller' => 'index',
    ]
);

Even if there is a view associated with the current action, it will not be rendered since redirect disables the view.

HTTP Cache

One of the easiest ways to improve the performance in your applications and reduce the traffic is using HTTP Cache. Most modern browsers support HTTP caching and is one of the reasons why many websites are currently fast.

HTTP Cache can be altered in the following header values sent by the application when serving a page for the first time:

  • Expires:このヘッダーを使用すると、アプリケーションは将来の日付を設定したり、ページが期限切れになったときにブラウザに通知したりすることができます。
  • Cache-Control:このヘッダーは、ページをブラウザーが新しいと判断する時間を指定できます。
  • Last-Modified:このヘッダーはブラウザへ、サイトの最終更新時を伝えて、ページの再読み込みを回避させます。
  • ETag:Etag はユニークなIDです。その中には現在のページの変更のタイムスタンプを含んでいます。

Setting an Expiration Time

The expiration date is one of the easiest and most effective ways to cache a page in the client (browser). Starting from the current date we add the amount of time the page will be stored in the browser cache. Until this date expires no new content will be requested from the server:

<?php

$expiryDate = new DateTime();
$expiryDate->modify('+2 months');

$response->setExpires($expiryDate);

The Response component automatically shows the date in GMT timezone as expected in an Expires header.

If we set this value to a date in the past the browser will always refresh the requested page:

<?php

$expiryDate = new DateTime();
$expiryDate->modify('-10 minutes');

$response->setExpires($expiryDate);

Browsers rely on the client’s clock to assess if this date has passed or not. The client clock can be modified to make pages expire and this may represent a limitation for this cache mechanism.

Cache-Control

This header provides a safer way to cache the pages served. We simply must specify a time in seconds telling the browser how long it must keep the page in its cache:

<?php

// 今から1日間ページをキャシュ
$response->setHeader('Cache-Control', 'max-age=86400');

The opposite effect (avoid page caching) is achieved in this way:

<?php

// 提供したページをキャッシュさせない
$response->setHeader('Cache-Control', 'private, max-age=0, must-revalidate');

E-Tag

An entity-tag or E-tag is a unique identifier that helps the browser realize if the page has changed or not between two requests. The identifier must be calculated taking into account that this must change if the previously served content has changed:

<?php

// 最新Newsの修正時間を元にE-Tagを計算する。
$mostRecentDate = News::maximum(
    [
        'column' => 'created_at'
    ]
);

$eTag = md5($mostRecentDate);

// E-Tag ヘッダを送信
$response->setHeader('E-Tag', $eTag);