Developing software in the Real World
I'm delighted to announce my new venture, PHP Training, with my friend Gary Hockin. As you can probably guess from the name, PHP Training is a training organisation where we provide public training courses on topics related to PHP. These courses will be held in person, initially at various venues in the UK, and are taught by Gary and myself. Both of us are experienced trainers and this is the first time we've offered training… continue reading.
When creating new OpenWhisk actions in PHP, It's likely that you'll want to take advantage of the rich ecosystem of Composer packages on Packagist.org. The OpenWhisk PHP runtime has you covered with some pre-installed Composer packages and also the ability to upload your own using a zip file. Pre-installed Composer packages The PHP runtime ships with two Composer packages by default: Guzzle and ramsey/uuid. This is handy as if you need to make an API… continue reading.
On a recent project, I needed to implement CORS support for my Expressive API. The easiest way to do this is to use Mike Tuupola's PSR-7 CORS Middleware. As this is a standard Slim-Style PSR-7 middleware implementation, we need to wrap it for Expressive, so we make a factory: App/Factory/CorsMiddlewareFactory.php:
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<?php declare(strict_types=1); namespace App\Factory; use Tuupola\Middleware\Cors; use Zend\Diactoros\Response; use Zend\Stratigility\Middleware\CallableMiddlewareWrapper; class CorsMiddlewareFactory { public function __invoke($container) { return new CallableMiddlewareWrapper( new Cors([ "origin" => ["*"], "methods" => ["GET", "POST", "PUT", "PATCH", "DELETE"], "headers.allow" => ["Content-Type", "Accept"], "headers.expose" => [], "credentials" => false, "cache" => 0, ]), new Response() ); } } |
We then register this in our App\ConfigProvider::getDependencies() by adding to the factories key so that it looks something like this:
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'factories' => [ Action\HomePageAction::class => Action\HomePageFactory::class, \Tuupola\Middleware\Cors::class => Factory\CorsMiddlewareFactory::class, ], |
If you don't… continue reading.
I find the Whoops error handler page in Expressive quite hard to read and particularly dislike that the error message displayed in the top left is hidden if it's more than a few words long. To fix this, I discovered that you can provide a custom CSS file to the PrettyPrintHandler and then override to your heart's content! One way to do this is to add a delegator factory to add the additional functionality, so… continue reading.
When developing an Expressive application, if you use var_dump(), echo, print_r(), etc when you get this error:
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Fatal error: Uncaught RuntimeException: Output has been emitted previously; cannot emit response in /www/dev/rka/example-app/vendor/zendframework/zend-diactoros/src/Response/SapiEmitterTrait.php:31 |
This occurs after your data has been displayed and makes perfect sense as Expressive is unable to send headers as you've already started sending the body. To solve this, you need some middleware. It looks like this:
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<?php namespace Akrabat\Middleware; use const Webimpress\HttpMiddlewareCompatibility\HANDLER_METHOD; use Psr\Http\Message\ResponseInterface; use Psr\Http\Message\ServerRequestInterface; use Webimpress\HttpMiddlewareCompatibility\HandlerInterface as DelegateInterface; use Webimpress\HttpMiddlewareCompatibility\MiddlewareInterface; use Zend\Diactoros\Stream; class OutputBufferMiddleware implements MiddlewareInterface { const APPEND = 'append'; const PREPEND = 'prepend'; protected $style; /** * Constructor * * @param string $style Either "append" or "prepend" */ public function __construct(string $style = 'prepend') { if (!is_string($style) || !in_array($style, [static::APPEND, static::PREPEND])) { throw new \InvalidArgumentException('Invalid style. Must be one of: append, prepend'); } $this->style = $style; } /** * Append or Prepend any data in the output buffer to the repsonse */ public function process(ServerRequestInterface $request, DelegateInterface $delegate) : ResponseInterface { try { ob_start(); $response = $delegate->{HANDLER_METHOD}($request); $output = ob_get_clean(); } catch (\Throwable $e) { ob_end_clean(); throw $e; } if (!empty($output) && $response->getBody()->isWritable()) { if ($this->style === static::PREPEND) { $body = new Stream('php://temp', 'wb+'); $body->write($output . "\n" . $response->getBody()); $response = $response->withBody($body); } elseif ($this->style === static::APPEND) { $response->getBody()->write($output); } } return $response; } } |
This middleware wraps all subsequent middleware in an output buffer and then either appends or prepends the contents to… continue reading.
If you're not using the Whoops error handler with Expressive and are using the Twig renderer, then you are given no information about the problem that occurred, even in debug mode. To fix this, I changed error.html.twig to this:
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{% extends '@layout/default.html.twig' %} {% block title %}{{ status }} {{ reason }}{% endblock %} {% block content %} <h1>Oops!</h1> <h2>This is awkward.</h2> <p>We encountered a {{ status }} {{ reason }} error.</p> {% if status == 404 %} <p> You are looking for something that doesn't exist or may have moved. Check out one of the links on this page or head back to <a href="{{ path('home') }}">Home</a>. </p> {% endif %} {% if error %} <h2>Error details</h2> <p>Message: <strong>{{ error.getMessage() }}</strong></p> <p>in <tt>{{ error.getFile() }}:{{ error.getLine() }}</tt></p> <p>Trace:</p> <pre>{{ error.getTraceAsString() }}</pre> {% set prev = error.getPrevious() %} {% for i in 1..10000 if prev %} <h3>Previous error</h3> <p>Message: <strong>{{ prev.getMessage() }}</strong></p> <p>in <tt>{{ prev.getFile() }}:{{ prev.getLine() }}</tt></p> <p>Trace:</p> <pre>{{ prev.getTraceAsString() }}</pre> {% set prev = prev.getPrevious() %} {% endfor %} {% endif %} {% endblock %} |
The new part is the within the {% if error %} block. In debug mode, error is set to the exception that was thown and is blank otherwise, so you won't leak sensitive information (as… continue reading.
My favourite tool for working with APIs is curl, though I recognise that lots of people like HTTPie and seem very keen to tell about it every time I mention curl… With curl, I particularly like using the -i switch to view the status line and headers too without the additional cruft of -v: This generates an output that looks like this:
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$ curl -i https://api.joind.in HTTP/1.1 200 OK Date: Wed, 04 Oct 2017 09:51:46 GMT Server: Apache X-Powered-By: PHP/5.6.4 Access-Control-Allow-Origin: * Content-Length: 363 Content-Type: application/json; charset=utf8 {"events":"https:\/\/api.joind.in\/v2.1\/events","hot-events":"https:\/\/api.joind.in\/v2.1\/events?filter=hot","upcoming-events":"https:\/\/api.joind.in\/v2.1\/events?filter=upcoming","past-events":"https:\/\/api.joind.in\/v2.1\/events?filter=past","open-cfps":"https:\/\/api.joind.in\/v2.1\/events?filter=cfp","docs":"http:\/\/joindin.github.io\/joindin-api\/"} |
What I would like to do is pretty print the body if… continue reading.
I'm adding a new feature to ZF's Problem-Details component and it's easiest to do this within the context of the application I'm developing. The component lives in vendor/zendframework/zend-problem-details and was installed using composer require so doesn't have its own git repository as the distribution zip file was used to install it. To change it to a git repository, we can use the –prefer-source option and specify a branch like this:
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$ composer require --prefer-source zendframework/zend-problem-details:dev-master |
I now have a… continue reading.
By default, OpenWhisk will handle the relevant responses for CORS. Specifically, it will respond to an OPTIONS request with these headers:
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Access-Control-Allow-Origin: * Access-Control-Allow-Methods: OPTIONS, GET, DELETE, POST, PUT, HEAD, PATCH Access-Control-Allow-Headers: Authorization, Content-Type |
If you need to change what is sent or you don't want to send these headers at all, then you need to do set the annotation web-custom-options to true and handle the OPTIONS header yourself. Note that if you don't set this annotation, you must not set any of these headers yourself as… continue reading.
Having successfully deployed a PHP application to Cloud Foundry, I needed a PostgreSQL database for persistent storage. I found Lorna Mitchell's Connecting PHP to MySQL on Bluemix helpful and this article expands on that information. I want to create a cloud-based PostgreSQL database and connect it to Laravel's Eloquent in a Cloud Foundry application. This is how to do it. Create the database instance As I'm using Bluemix for my Cloud Foundry hosting, I'm using… continue reading.
