diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7579f74
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+vendor
+composer.lock
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..cfbeff0
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,19 @@
+# How to Contribute
+
+## Pull Requests
+
+1. Fork this repository
+2. Create a new branch for each feature or improvement
+3. Send a pull request from each feature branch
+
+It is very important to separate new features or improvements into separate feature branches, and to send a pull request for each branch. This allows me to review and pull in new features or improvements individually.
+
+## Style Guide
+
+All pull requests must adhere to the [PSR-2 standard](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-2-coding-style-guide.md).
+
+## Unit Testing
+
+All pull requests must be accompanied by passing unit tests and complete code coverage. The Slim Framework uses phpunit for testing.
+
+[Learn about PHPUnit](https://github.com/sebastianbergmann/phpunit/)
diff --git a/LICENSE.md b/LICENSE.md
new file mode 100644
index 0000000..130902a
--- /dev/null
+++ b/LICENSE.md
@@ -0,0 +1,19 @@
+Copyright (c) 2012-2015 Josh Lockhart
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..353778a
--- /dev/null
+++ b/README.md
@@ -0,0 +1,57 @@
+# Slim Framework HTTP Cache
+
+This repository contains a Slim Framework HTTP cache middleware and service provider.
+
+## Install
+
+Via Composer
+
+``` bash
+$ composer require slim/httpcache
+```
+
+Requires Slim 3.0.0 or newer.
+
+## Usage
+
+```php
+$app = new \Slim\App();
+
+// Register middleware
+$app->add(new \Slim\HttpCache\Cache('public', 86400));
+
+// Register service provider
+$app->register(new \Slim\HttpCache\CacheProvider);
+
+// Example route with ETag header
+$app->get('/foo', function ($req, $res, $args) {
+    $resWithEtag = $this['cache']->withEtag($res, 'abc');
+
+    return $resWithEtag;
+});
+
+$app->run();
+```
+
+## Testing
+
+``` bash
+$ phpunit
+```
+
+## Contributing
+
+Please see [CONTRIBUTING](CONTRIBUTING.md) for details.
+
+## Security
+
+If you discover any security related issues, please email security@slimframework.com instead of using the issue tracker.
+
+## Credits
+
+- [Josh Lockhart](https://github.com/codeguy)
+- [All Contributors](../../contributors)
+
+## License
+
+The MIT License (MIT). Please see [License File](LICENSE.md) for more information.
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..bc18ce9
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,33 @@
+{
+    "name": "slim/http-cache",
+    "type": "library",
+    "description": "Slim Framework HTTP cache middleware and service provider",
+    "keywords": ["slim","framework","middleware","cache"],
+    "homepage": "http://slimframework.com",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Josh Lockhart",
+            "email": "hello@joshlockhart.com",
+            "homepage": "http://joshlockhart.com"
+        }
+    ],
+    "require": {
+        "php": ">=5.4.0",
+        "pimple/pimple": "~3.0",
+        "psr/http-message": "~0.9"
+    },
+    "require-dev": {
+        "slim/slim": "dev-develop"
+    },
+    "autoload": {
+        "psr-4": {
+            "Slim\\HttpCache\\": "src"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "Slim\\HttpCache\\Tests\\": "tests"
+        }
+    }
+}
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
new file mode 100644
index 0000000..8259dc4
--- /dev/null
+++ b/phpunit.xml.dist
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<phpunit backupGlobals="false"
+         backupStaticAttributes="false"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         processIsolation="false"
+         stopOnFailure="false"
+         syntaxCheck="false"
+         bootstrap="tests/bootstrap.php"
+>
+    <testsuites>
+        <testsuite name="Slim Test Suite">
+            <directory>tests/</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist>
+            <directory>src/</directory>
+        </whitelist>
+    </filter>
+</phpunit>
diff --git a/src/Cache.php b/src/Cache.php
new file mode 100644
index 0000000..9fb223b
--- /dev/null
+++ b/src/Cache.php
@@ -0,0 +1,83 @@
+<?php
+namespace Slim\HttpCache;
+
+use Pimple\Container;
+use Pimple\ServiceProviderInterface;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+class Cache
+{
+    /**
+     * Cache-Control type (public or private)
+     *
+     * @var string
+     */
+    protected $type;
+
+    /**
+     * Cache-Control max age in seconds
+     *
+     * @var int
+     */
+    protected $maxAge;
+
+    /**
+     * Create new HTTP cache
+     *
+     * @param string $type   The cache type: "public" or "private"
+     * @param int    $maxAge The maximum age of client-side cache
+     */
+    public function __construct($type = 'private', $maxAge = 86400)
+    {
+        $this->type = $type;
+        $this->maxAge = $maxAge;
+    }
+
+    /**
+     * Invoke cache middleware
+     *
+     * @param  RequestInterface  $request  A PSR7 request object
+     * @param  ResponseInterface $response A PSR7 response object
+     * @param  callable          $next     The next middleware callable
+     *
+     * @return ResponseInterface           A PSR7 response object
+     */
+    public function __invoke(RequestInterface $request, ResponseInterface $response, callable $next)
+    {
+        $response = $next($request, $response);
+
+        // Cache-Control header
+        $response = $response->withHeader('Cache-Control', sprintf(
+            '%s, max-age=%s',
+            $this->type,
+            $this->maxAge
+        ));
+
+        // Last-Modified header and conditional GET check
+        $lastModified = $response->getHeader('Last-Modified');
+        if ($lastModified) {
+            if (!is_integer($lastModified)) {
+                $lastModified = strtotime($lastModified);
+            }
+            $ifModifiedSince = $request->getHeader('If-Modified-Since');
+            if ($ifModifiedSince && $lastModified === strtotime($ifModifiedSince)) {
+                return $response->withStatus(304);
+            }
+        }
+
+        // ETag header and conditional GET check
+        $etag = $response->getHeader('ETag');
+        if ($etag) {
+            $ifNoneMatch = $request->getHeader('If-None-Match');
+            if ($ifNoneMatch) {
+                $etagList = preg_split('@\s*,\s*@', $ifNoneMatch);
+                if (in_array($etag, $etagList) || in_array('*', $etagList)) {
+                    return $response->withStatus(304);
+                }
+            }
+        }
+
+        return $response;
+    }
+}
diff --git a/src/CacheProvider.php b/src/CacheProvider.php
new file mode 100644
index 0000000..693d7bc
--- /dev/null
+++ b/src/CacheProvider.php
@@ -0,0 +1,81 @@
+<?php
+namespace Slim\HttpCache;
+
+use Pimple\Container;
+use Pimple\ServiceProviderInterface;
+use Psr\Http\Message\ResponseInterface;
+
+class CacheProvider implements ServiceProviderInterface
+{
+    /**
+     * Register this cache provider with a Pimple container
+     *
+     * @param  Container $container
+     */
+    public function register(Container $container)
+    {
+        $container['cache'] = $this;
+    }
+
+    /**
+     * Add `Expires` header to PSR7 response object
+     *
+     * @param  ResponseInterface $response A PSR7 response object
+     * @param  int|string        $time     A UNIX timestamp or a valid `strtotime()` string
+     *
+     * @return ResponseInterface A new PSR7 response object with `Expires` header
+     */
+    public function withExpires(ResponseInterface $response, $time)
+    {
+        if (!is_integer($time)) {
+            $time = strtotime($time);
+            if ($time === false) {
+                throw new \InvalidArgumentException('Expiration value could not be parsed with `strtotime()`.');
+            }
+        }
+
+        return $response->withHeader('Expires', gmdate('D, d M Y H:i:s T', $time));
+    }
+
+    /**
+     * Add `ETag` header to PSR7 response object
+     *
+     * @param  ResponseInterface $response A PSR7 response object
+     * @param  string            $value    The ETag value
+     * @param  string            $type     ETag type: "strong" or "weak"
+     *
+     * @return ResponseInterface           A new PSR7 response object with `ETag` header
+     */
+    public function withEtag(ResponseInterface $response, $value, $type = 'strong')
+    {
+        if (!in_array($type, ['strong', 'weak'])) {
+            throw new \InvalidArgumentException('Invalid etag type. Must be "strong" or "weak".');
+        }
+        $value = '"' . $value . '"';
+        if ($type === 'weak') {
+            $value = 'W/' . $value;
+        }
+
+        return $response->withHeader('ETag', $value);
+    }
+
+    /**
+     * Add `Last-Modified` header to PSR7 response object
+     *
+     * @param  ResponseInterface $response A PSR7 response object
+     * @param  int|string        $time     A UNIX timestamp or a valid `strtotime()` string
+     *
+     * @return ResponseInterface           A new PSR7 response object with `Last-Modified` header
+     */
+    public function withLastModified(ResponseInterface $response, $time)
+    {
+        if (!is_integer($time)) {
+            $time = strtotime($time);
+            if ($time === false) {
+                throw new \InvalidArgumentException('Last Modified value could not be parsed with `strtotime()`.');
+            }
+        }
+
+        return $response->withHeader('Last-Modified', gmdate('D, d M Y H:i:s T', $time));
+    }
+}
diff --git a/tests/CacheProviderTest.php b/tests/CacheProviderTest.php
new file mode 100644
index 0000000..d2112d9
--- /dev/null
+++ b/tests/CacheProviderTest.php
@@ -0,0 +1,54 @@
+<?php
+namespace Slim\HttpCache\Tests;
+
+use Slim\HttpCache\CacheProvider;
+use Slim\Http\Response;
+
+class CacheProviderTest extends \PHPUnit_Framework_TestCase
+{
+    public function testWithExpires()
+    {
+        $now = time();
+        $cacheProvider = new CacheProvider();
+        $res = $cacheProvider->withExpires(new Response(), $now);
+
+        $this->assertEquals(gmdate('D, d M Y H:i:s T', $now), $res->getHeader('Expires'));
+    }
+
+    public function testWithETag()
+    {
+        $etag = 'abc';
+        $cacheProvider = new CacheProvider();
+        $res = $cacheProvider->withEtag(new Response(), $etag);
+
+        $this->assertEquals('"' . $etag . '"', $res->getHeader('ETag'));
+    }
+
+    public function testWithETagWeak()
+    {
+        $etag = 'abc';
+        $cacheProvider = new CacheProvider();
+        $res = $cacheProvider->withEtag(new Response(), $etag, 'weak');
+
+        $this->assertEquals('W/"' . $etag . '"', $res->getHeader('ETag'));
+    }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     */
+    public function testWithETagInvalidType()
+    {
+        $etag = 'abc';
+        $cacheProvider = new CacheProvider();
+        $cacheProvider->withEtag(new Response(), $etag, 'bork');
+    }
+
+    public function testWithLastModified()
+    {
+        $now = time();
+        $cacheProvider = new CacheProvider();
+        $res = $cacheProvider->withLastModified(new Response(), $now);
+
+        $this->assertEquals(gmdate('D, d M Y H:i:s T', $now), $res->getHeader('Last-Modified'));
+    }
+}
diff --git a/tests/CacheTest.php b/tests/CacheTest.php
new file mode 100644
index 0000000..2cdd207
--- /dev/null
+++ b/tests/CacheTest.php
@@ -0,0 +1,99 @@
+<?php
+namespace Slim\HttpCache\Tests;
+
+use Slim\HttpCache\Cache;
+use Slim\Http\Request;
+use Slim\Http\Response;
+use Slim\Http\Uri;
+use Slim\Http\Headers;
+use Slim\Http\Body;
+use Slim\Collection;
+
+class CacheTest extends \PHPUnit_Framework_TestCase
+{
+    public function requestFactory()
+    {
+        $uri = Uri::createFromString('https://example.com:443/foo/bar?abc=123');
+        $headers = new Headers();
+        $cookies = new Collection();
+        $serverParams = new Collection();
+        $body = new Body(fopen('php://temp', 'r+'));
+
+        return new Request('GET', $uri, $headers, $cookies, $serverParams, $body);
+    }
+
+    public function testCacheControlHeader()
+    {
+        $cache = new Cache('public', 86400);
+        $req = $this->requestFactory();
+        $res = new Response();
+        $next = function (Request $req, Response $res) {
+            return $res;
+        };
+        $res = $cache($req, $res, $next);
+
+        $this->assertEquals('public, max-age=86400', $res->getHeader('Cache-Control'));
+    }
+
+    public function testLastModifiedWithCacheHit()
+    {
+        $now = time();
+        $lastModified = gmdate('D, d M Y H:i:s T', $now + 86400);
+        $ifModifiedSince = gmdate('D, d M Y H:i:s T', $now + 86400);
+        $cache = new Cache('public', 86400);
+        $req = $this->requestFactory()->withHeader('If-Modified-Since', $ifModifiedSince);
+        $res = new Response();
+        $next = function (Request $req, Response $res) use ($lastModified) {
+            return $res->withHeader('Last-Modified', $lastModified);
+        };
+        $res = $cache($req, $res, $next);
+
+        $this->assertEquals(304, $res->getStatusCode());
+    }
+
+    public function testLastModifiedWithCacheMiss()
+    {
+        $now = time();
+        $lastModified = gmdate('D, d M Y H:i:s T', $now + 86400);
+        $ifModifiedSince = gmdate('D, d M Y H:i:s T', $now - 86400);
+        $cache = new Cache('public', 86400);
+        $req = $this->requestFactory()->withHeader('If-Modified-Since', $ifModifiedSince);
+        $res = new Response();
+        $next = function (Request $req, Response $res) use ($lastModified) {
+            return $res->withHeader('Last-Modified', $lastModified);
+        };
+        $res = $cache($req, $res, $next);
+
+        $this->assertEquals(200, $res->getStatusCode());
+    }
+
+    public function testETagWithCacheHit()
+    {
+        $etag = 'abc';
+        $ifNoneMatch = 'abc';
+        $cache = new Cache('public', 86400);
+        $req = $this->requestFactory()->withHeader('If-None-Match', $ifNoneMatch);
+        $res = new Response();
+        $next = function (Request $req, Response $res) use ($etag) {
+            return $res->withHeader('ETag', $etag);
+        };
+        $res = $cache($req, $res, $next);
+
+        $this->assertEquals(304, $res->getStatusCode());
+    }
+
+    public function testETagWithCacheMiss()
+    {
+        $etag = 'abc';
+        $ifNoneMatch = 'xyz';
+        $cache = new Cache('public', 86400);
+        $req = $this->requestFactory()->withHeader('If-None-Match', $ifNoneMatch);
+        $res = new Response();
+        $next = function (Request $req, Response $res) use ($etag) {
+            return $res->withHeader('ETag', $etag);
+        };
+        $res = $cache($req, $res, $next);
+
+        $this->assertEquals(200, $res->getStatusCode());
+    }
+}
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
new file mode 100644
index 0000000..5330160
--- /dev/null
+++ b/tests/bootstrap.php
@@ -0,0 +1,2 @@
+<?php
+require dirname(__DIR__) . '/vendor/autoload.php';