使用缓存提高性能（Improving Performance with Cache）¶

<?php

use Phalcon\Tag;
use Phalcon\Cache\Backend\File as BackFile;
use Phalcon\Cache\Frontend\Output as FrontOutput;

// Create an Output frontend. Cache the files for 2 days
$frontCache = new FrontOutput(
    array(
        "lifetime" => 172800
    )
);

// Create the component that will cache from the "Output" to a "File" backend
// Set the cache file directory - it's important to keep the "/" at the end of
// the value for the folder
$cache = new BackFile(
    $frontCache,
    array(
        "cacheDir" => "../app/cache/"
    )
);

// Get/Set the cache file to ../app/cache/my-cache.html
$content = $cache->start("my-cache.html");

// If $content is null then the content will be generated for the cache
if ($content === null) {

    // Print date and time
    echo date("r");

    // Generate a link to the sign-up action
    echo Tag::linkTo(
        array(
            "user/signup",
            "Sign Up",
            "class" => "signup-button"
        )
    );

    // Store the output into the cache file
    $cache->save();

} else {

    // Echo the cached output
    echo $content;
}

<?php

// Retrieve products by key "myProducts"
$products = $cache->get("myProducts");

<?php

// Query all keys used in the cache
$keys = $cache->queryKeys();
foreach ($keys as $key) {
    $data = $cache->get($key);
    echo "Key=", $key, " Data=", $data;
}

// Query keys in the cache that begins with "my-prefix"
$keys = $cache->queryKeys("my-prefix");

<?php

// Delete an item with a specific key
$cache->delete("someKey");

// Delete all items from the cache
$keys = $cache->queryKeys();
foreach ($keys as $key) {
    $cache->delete($key);
}

<?php

if ($cache->exists("someKey")) {
    echo $cache->get("someKey");
} else {
    echo "Cache does not exists!";
}

<?php

$cacheKey = 'my.cache';

// Setting the cache when getting a result
$robots = $cache->get($cacheKey, 3600);
if ($robots === null) {

    $robots = "some robots";

    // Store it in the cache
    $cache->save($cacheKey, $robots);
}

<?php

$cacheKey = 'my.cache';

$robots = $cache->get($cacheKey);
if ($robots === null) {

    $robots = "some robots";

    // Setting the cache when saving data
    $cache->save($cacheKey, $robots, 3600);
}

<?php

use Phalcon\Cache\Multiple;
use Phalcon\Cache\Backend\Apc as ApcCache;
use Phalcon\Cache\Backend\File as FileCache;
use Phalcon\Cache\Frontend\Data as DataFrontend;
use Phalcon\Cache\Backend\Memcached as MemcachedCache;

$ultraFastFrontend = new DataFrontend(
    array(
        "lifetime" => 3600
    )
);

$fastFrontend = new DataFrontend(
    array(
        "lifetime" => 86400
    )
);

$slowFrontend = new DataFrontend(
    array(
        "lifetime" => 604800
    )
);

// Backends are registered from the fastest to the slower
$cache = new Multiple(
    array(
        new ApcCache(
            $ultraFastFrontend,
            array(
                "prefix" => 'cache',
            )
        ),
        new MemcachedCache(
            $fastFrontend,
            array(
                "prefix" => 'cache',
                "host"   => "localhost",
                "port"   => "11211"
            )
        ),
        new FileCache(
            $slowFrontend,
            array(
                "prefix"   => 'cache',
                "cacheDir" => "../app/cache/"
            )
        )
    )
);

// Save, saves in every backend
$cache->save('my-key', $data);