[server] Add list-reading-types API action

README.md

@@ -84,9 +84,13 @@ Parameter			| Type		| Meaning
 
 Examples:
 
+### list-reading-types
+> Lists the different types of readings that can be specified.
+
+_No parameters are currently supported by this action._
+
 ```
-https://example.com/path/to/api.php?action=device-info&device-id=10
-https://example.com/path/to/api.php?action=device-info&device-id=18
+https://example.com/path/to/api.php?action=list-reading-types
 ```
 
 ## Notes

logic/Actions/ListDevices.php

@@ -6,7 +6,6 @@ use \SBRL\TomlConfig;
 use \AirQuality\Repositories\IDeviceRepository;
 use \AirQuality\ApiResponseSender;
 
-use \AirQuality\Validator;
 use \AirQuality\PerfFormatter;
 
 class ListDevices implements IAction {

logic/Actions/ListReadingTypes.php

@@ -0,0 +1,63 @@
+<?php
+
+namespace AirQuality\Actions;
+
+use \SBRL\TomlConfig;
+use \AirQuality\Repositories\IMeasurementTypeRepository;
+use \AirQuality\ApiResponseSender;
+
+use \AirQuality\PerfFormatter;
+
+class ListReadingTypes implements IAction {
+	/** @var TomlConfig */
+	private $settings;
+	/** @var IMeasurementTypeRepository */
+	private $types_repo;
+	
+	/** @var ApiResponseSender */
+	private $sender;
+	
+	public function __construct(
+		TomlConfig $in_settings,
+		IMeasurementTypeRepository $in_types_repo,
+		ApiResponseSender $in_sender) {
+		$this->settings = $in_settings;
+		$this->types_repo = $in_types_repo;
+		$this->sender = $in_sender;
+	}
+	
+	public function handle() : bool {
+		global $start_time;
+		
+		$start_handle = microtime(true);
+		
+		// 1: Parse & validate parameters
+		
+		// 1: Pull data from database
+		$data = $this->types_repo->get_all_types();
+		
+		// 1.5: Validate data from database
+		if(empty($data)) {
+			http_response_code(404);
+			header("content-type: text/plain");
+			header("x-time-taken: " . PerfFormatter::format_perf_data($start_time, $start_handle, null));
+			echo("Error: No types are currently present in the system.");
+			return false;
+		}
+		
+		// 3: Serialise data
+		$start_encode = microtime(true);
+		$response = json_encode($data);
+		
+		// 4: Send response
+		
+		// Don't a cache control header, because new types might get added at any time
+		// TODO: Investigate adding a short-term (~10mins?) cache-control header here
+		
+		header("content-length: " . strlen($response));
+		header("content-type: application/json");
+		header("x-time-taken: " . PerfFormatter::format_perf_data($start_time, $start_handle, $start_encode));
+		echo($response);
+		return true;
+	}
+}