Implemented new saveAddresses method in Dart

Fixes the bug, that long list can't be sent via get methods.

res/dart/main.dart

@@ -1,14 +1,20 @@
 // Copyright (c) 2016 - 2017, Marcel Kapfer (mmk2410).
 // MIT License
 
+/// frontend code for filespread, a simple file over email spreading web app.
 import 'dart:convert';
 import 'dart:html';
 
+/// main method with click listners.
 void main() {
   // send mail listener
   querySelector("#send").onClick.listen(sendMail);
+
+  // save address list listner
+  querySelector("#save-addresses").onClick.listen(saveAddresses);
 }
 
+/// function for calling the backend to send mails.
 void sendMail(MouseEvent event) {
   InputElement title = querySelector("#mailtitle");
   InputElement text = querySelector("#mailtext");
@@ -26,12 +32,52 @@ void sendMail(MouseEvent event) {
 
   String url = "res/php/sendmail.php?data=${JSON.encode(data)}";
 
-  HttpRequest.getString(url).then((response) {
+  HttpRequest.getString(url).then((String response) {
     if (response == "0") {
       window.alert("Mails successfully sent.");
     } else {
       window.alert("Failed to send mail.");
     }
   });
-
+}
+
+/// function to update the addresses list in the backend.
+void saveAddresses(MouseEvent event) {
+  TextAreaElement addresses = querySelector("#edit-addresses");
+  SelectElement list = querySelector("#edit-address-list");
+
+  List<String> addressesList = new List();
+
+  addresses.value.split("\n").forEach((String address) {
+    if (address.isNotEmpty) addressesList.add(address);
+  });
+
+  Map data = {"list": list.value, "addresses": addressesList};
+
+  String url = "res/php/savelist.php";
+
+  HttpRequest.postFormData(url, {"data": JSON.encode(data)}).then((HttpRequest response) {
+    if (response.responseText == "0") {
+      window.alert("Addresses sucessfully saved.");
+      updateAddresses(addressesList, list.value);
+    } else {
+      window.alert("Failed to save adresses.");
+    }
+  });
+}
+
+/// Updated the frontend after an address change.
+void updateAddresses(List<String> addresses, String list) {
+  SelectElement currentList = querySelector("#address_list");
+
+  if (currentList.value == list) {
+    DivElement addressesContainer = querySelector("#addresses");
+    addressesContainer.children .removeWhere((Element child) => addressesContainer.children.contains(child));
+
+    addresses.forEach((String address) {
+      ParagraphElement addressElement = new ParagraphElement();
+      addressElement.text = address;
+      addressesContainer.children.add(addressElement);
+    });
+  }
 }

res/php/savelist.php

@@ -1,8 +1,8 @@
 <?php
-# COPYRIGHT (c) 2016 Marcel Kapfer (mmk2410)
+# COPYRIGHT (c) 2016-2017 Marcel Kapfer (mmk2410)
 # MIT License
 
-$content = $_GET["data"];
+$content = json_decode($_POST["data"], true);
 
 $filename = "../../lists/" . $content["list"];