Asynchronous API calls from PHP application using Slim + Guzzle - php

Question

I'm working on a php application using Slim framework. My application homepage is making about 20 REST API calls, which is slowing down the page load.
I read that I can use Http Clients like Guzzle to call these API's asynchronously but I couldn't find any article that tells how to use Guzzle with Slim.
Can someone tell how to use Guzzle with Slim.
Or is there any other solution that can speed up the page load?
N.B: I'm a novice in PHP

Answer 1

To use Guzzle with Slim, you need to
Install it by running composer
$ composer require guzzlehttp/guzzle:~6.0
Guzzle installation
Guzzle Quickstart
Create dependency registration, for example
<?php
use GuzzleHttp\Client;
$container = $app->getContainer();
$container['httpClient'] = function ($cntr) {
return new Client();
};
and put it somewhere where it will be executed when index.php the main bootstrap file is loaded.
Then in your code, you can get guzzle instance from container
$guzzle = $container->httpClient;
For example if you have following route
$app->get('/example', App\Controllers\Example::class);
And controller Example as follow
<?php
namespace App\Controllers;
use GuzzleHttp\ClientInterface;
use Psr\Http\Message\ServerRequestInterface as Request;
use Psr\Http\Message\ResponseInterface as Response;
class Example
{
private $httpClient;
public function __construct(ClientInterface $httpClient)
{
$this->httpClient = $httpClient;
}
public function __invoke(Request $request, Response $response, array $args)
{
//call api, etc..etc
$apiResponse = $this->httpClient->get('http://api.blabla.org/get');
//do something with api response
return $response;
}
}
To inject guzzle instance to Example controller, you create its dependency registration
use App\Controllers\Example;
$container[Example::class] = function ($cntr) {
return new Example($cntr->httpClient);
}
To speed up your page load, if you are API developer then start from there. If you are not API developer and have no control, try to think if you can reduce number of API calls by removing non essential ones. Or as last resort, cache API call response to storage that is faster for your application to retrieve later.
For example using redis.
You calculate hash of API url call including its querystring and use hash as key to access cached API call response.