OpenWeatherMap provides a free tier weather API that is detail-packed and easy to use. The API outline can be seen here, In this post I will cover the current weather data and the hourly forecast.
To get a free OpenWeatherMap API key sign up here. This free level gets you 60 calls per minute.
A good starting point is to build an easy to read PHP class built around a simple query builder and GET request with curl. The full code is at the bottom of this page otherwise view it on GitHub.
Building a class
Assume all the following code is in the weatherApp class:
const URI = 'https://api.openweathermap.org/data/2.5/';
private $api_key;
private $data;
public function __construct($api_key)
{
if (!isset($api_key) or trim($api_key) == '') {
throw new Exception("You must provide an API key!");
}
return $this->api_key = $api_key;
}Firstly setting a const for the main API URL base, this will get built onto for the calls later on. $api_key and $data get defined as private vars.
__construct() is used as an initializer for the class. It must be set with your API key otherwise the class cannot be used.
private function apiCall($url, $params = array())
{
$data = null;
$url = (self::URI . $url);
$curl = curl_init();
curl_setopt($curl, CURLOPT_TIMEOUT, 3);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
if (!empty($params)) {
$url = ($url . '?appid=' . $this->api_key . '&' . str_replace('%2C', ',', http_build_query($params, null)));
} else {
throw new Exception('params was empty');
}
curl_setopt($curl, CURLOPT_URL, $url);
$response = curl_exec($curl);
$responseInfo = curl_getinfo($curl);
switch ($responseInfo['http_code']) {
case 0:
throw new Exception('Timeout reached when calling ' . $url);
break;
case 200:
$data = $response;
break;
case 401:
throw new Exception('Unauthorized request to ' . $url . ': ' . json_decode($response)->message);
break;
case 404;
$data = null;
break;
default:
throw new Exception('Connect to API failed with response: ' . $responseInfo['http_code']);
break;
}
$this->data = $data;
return $data;
}apicall() builds the URL from parameters for a GET request which is done with cURL. The response to the call is also sorted and exceptions thrown in certain circumstances.
If the HTTP code was 200 then the call was ok and the returned API data gets assigned and returned.
public function generateCall($base, $params)
{
return $this->apiCall($base, $params);
}generateCall() is where the URL and parameters get assigned, its use is seen like:
$request->generateCall('weather', ["zip" => "3000,au", "units" => "metric"]);This is calling for the current weather at postcode 3000 in Australia with the units in metric.
When this is sent to apicall() the URL will be built into:
https://api.openweathermap.org/data/2.5/weather?appid=APIKEYHERE&zip=3000,au&units=metric
This is then sent into the cURL GET request, Effectively making the whole API GET request revolved around just a couple of functions. This can then also be adapted for other API uses.
Reading the return data is done with:
public function readCurrentData()
{
$data = json_decode($this->data, true);
$temp = $data['main']['temp'];
$max_temp = $data['main']['temp_max'];
$min_temp = $data['main']['temp_min'];
$pressure = $data['main']['pressure'];
$humidity = $data['main']['humidity'];
$wind_speed = $data['wind']['speed'];
$wind_direction = $data['wind']['deg'];
$call_id = $data['sys']['id'];
$clouds = $data['clouds']['all'];
$main = $data['weather'][0]['main'];
$desc = $data['weather'][0]['description'];
$icon = $data['weather'][0]['icon'];
if (isset($data['rain']['3h'])) {
$rain3h = $data['rain']['3h'];
} else {
$rain3h = 0;
}
}Doing a forecast call:
$request->generateCall('forecast', ["zip" => "3000,au", "units" => "metric"]);Changing weather to forecast in the params. Reading this data with:
public function readForecastData()
{
$data = json_decode($this->data, true);
foreach ($data['list'] as $val) {
$main = $val['main'];
$temp = $main['temp'];
$date = $val['dt_txt'];
$pressure = $main['pressure'];
$humidity = $main['humidity'];
$wind_speed = $val['wind']['speed'];
$wind_direction = $val['wind']['deg'];
$clouds = $val['clouds']['all'];
$weather = $val['weather'][0];
$main = $weather['main'];
$icon = $weather['icon'];
}
}Usage
Usage for the class weatherApp:
$call = new weatherApp("APIKEYHERE");//New api call
$current = $call->generateCall('weather', ["zip" => "3000,au", "units" => "metric"]);//Calls current data
$forecast = $call->generateCall('forecast', ["zip" => "3000,au", "units" => "metric"]);//Calls forecast dataFull code
The full code:
<?php
class weatherApp
{
const URI = 'https://api.openweathermap.org/data/2.5/';
private $api_key;
private $data;
/**
* Sets api key
* @param string $api_key
* @return string
* @throws Exception
*/
public function __construct($api_key)
{
if (!isset($api_key) or trim($api_key) == '') {
throw new Exception("You must provide an API key!");
}
return $this->api_key = $api_key;
}
/**
* GET api call
* @param string $url
* @param array $params
* @return string
* @throws Exception
*/
private function apiCall($url, $params = array())
{
$data = null;
$url = (self::URI . $url);
$curl = curl_init();
curl_setopt($curl, CURLOPT_TIMEOUT, 3);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
if (!empty($params)) {
$url = ($url . '?appid=' . $this->api_key . '&' . str_replace('%2C', ',', http_build_query($params, null)));
} else {
throw new Exception('params was empty');
}
curl_setopt($curl, CURLOPT_URL, $url);
$response = curl_exec($curl);
$responseInfo = curl_getinfo($curl);
switch ($responseInfo['http_code']) {
case 0:
throw new Exception('Timeout reached when calling ' . $url);
break;
case 200:
$data = $response;
break;
case 401:
throw new Exception('Unauthorized request to ' . $url . ': ' . json_decode($response)->message);
break;
case 404;
$data = null;
break;
default:
throw new Exception('Connect to API failed with response: ' . $responseInfo['http_code']);
break;
}
$this->data = $data;
return $data;
}
/**
* Generates a call with parameters
* @param string $base
* @param array $params
* @return string
*/
public function generateCall($base, $params)
{
return $this->apiCall($base, $params);
}
/**
* Access values from current data
*/
public function readCurrentData()
{
$data = json_decode($this->data, true);
$temp = $data['main']['temp'];
$max_temp = $data['main']['temp_max'];
$min_temp = $data['main']['temp_min'];
$pressure = $data['main']['pressure'];
$humidity = $data['main']['humidity'];
$wind_speed = $data['wind']['speed'];
$wind_direction = $data['wind']['deg'];
$call_id = $data['sys']['id'];
$clouds = $data['clouds']['all'];
$main = $data['weather'][0]['main'];
$desc = $data['weather'][0]['description'];
$icon = $data['weather'][0]['icon'];
if (isset($data['rain']['3h'])) {
$rain3h = $data['rain']['3h'];
} else {
$rain3h = 0;
}
}
/**
* Access values from forecast data
*/
public function readForecastData()
{
$data = json_decode($this->data, true);
foreach ($data['list'] as $val) {
$main = $val['main'];
$temp = $main['temp'];
$date = $val['dt_txt'];
$pressure = $main['pressure'];
$humidity = $main['humidity'];
$wind_speed = $val['wind']['speed'];
$wind_direction = $val['wind']['deg'];
$clouds = $val['clouds']['all'];
$weather = $val['weather'][0];
$main = $weather['main'];
$icon = $weather['icon'];
}
}
}