Add Content-Type response header for JSON responses (#90)

Signed-off-by: Benjamin Gaussorgues <[email protected]>
Co-authored-by: Josh Richards <[email protected]>

index.php

@@ -1294,6 +1294,7 @@ public function isAuthenticated(): bool {
 	if (isset($_POST['step'])) {
 		// mark step as failed
 		http_response_code(500);
+		header('Content-Type: application/json');
 		echo(json_encode(['proceed' => false, 'response' => $e->getMessage()]));
 		die();
 	}
@@ -1380,6 +1381,7 @@ public function isAuthenticated(): bool {
 				break;
 		}
 		$updater->endStep($step);
+		header('Content-Type: application/json');
 		echo(json_encode(['proceed' => true]));
 	} catch (UpdateException $e) {
 		$data = $e->getData();
@@ -1395,6 +1397,7 @@ public function isAuthenticated(): bool {
 			$updater->rollbackChanges($step);
 		}
 		http_response_code(500);
+		header('Content-Type: application/json');
 		echo(json_encode(['proceed' => false, 'response' => $data]));
 	} catch (\Exception $e) {
 		$message = $e->getMessage();
@@ -1410,6 +1413,7 @@ public function isAuthenticated(): bool {
 			$updater->rollbackChanges($step);
 		}
 		http_response_code(500);
+		header('Content-Type: application/json');
 		echo(json_encode(['proceed' => false, 'response' => $message]));
 	}