Migration to null safety dart 2.0

.gitignore

@@ -13,3 +13,5 @@ doc/api/
 
 .idea
 .dart_tool
+
+.vscode/

example/main.dart

@@ -5,13 +5,14 @@ void main() async {
   var client = http.Client();
 
   // RSS feed
-  var response = await client
-      .get('https://developer.apple.com/news/releases/rss/releases.rss');
+  var response = await client.get(
+      Uri(path: 'https://developer.apple.com/news/releases/rss/releases.rss'));
   var channel = RssFeed.parse(response.body);
   print(channel);
 
   // Atom feed
-  response = await client.get('https://www.theverge.com/rss/index.xml');
+  response =
+      await client.get(Uri(path: 'https://www.theverge.com/rss/index.xml'));
   var feed = AtomFeed.parse(response.body);
   print(feed);
 

lib/domain/atom_category.dart

@@ -1,9 +1,9 @@
 import 'package:xml/xml.dart';
 
 class AtomCategory {
-  final String term;
-  final String scheme;
-  final String label;
+  final String? term;
+  final String? scheme;
+  final String? label;
 
   AtomCategory(this.term, this.scheme, this.label);
 

lib/domain/atom_feed.dart

@@ -8,20 +8,20 @@ import 'package:webfeed/util/xml.dart';
 import 'package:xml/xml.dart';
 
 class AtomFeed {
-  final String id;
-  final String title;
-  final DateTime updated;
-  final List<AtomItem> items;
+  final String? id;
+  final String? title;
+  final DateTime? updated;
+  final List<AtomItem>? items;
 
-  final List<AtomLink> links;
-  final List<AtomPerson> authors;
-  final List<AtomPerson> contributors;
-  final List<AtomCategory> categories;
-  final AtomGenerator generator;
-  final String icon;
-  final String logo;
-  final String rights;
-  final String subtitle;
+  final List<AtomLink>? links;
+  final List<AtomPerson>? authors;
+  final List<AtomPerson>? contributors;
+  final List<AtomCategory>? categories;
+  final AtomGenerator? generator;
+  final String? icon;
+  final String? logo;
+  final String? rights;
+  final String? subtitle;
 
   AtomFeed({
     this.id,

lib/domain/atom_generator.dart

@@ -1,16 +1,14 @@
 import 'package:xml/xml.dart';
 
 class AtomGenerator {
-  final String uri;
-  final String version;
-  final String value;
+  final String? uri;
+  final String? version;
+  final String? value;
 
   AtomGenerator(this.uri, this.version, this.value);
 
-  factory AtomGenerator.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
+  static parse(XmlElement? element) {
+    if (element == null) return null;
     var uri = element.getAttribute('uri');
     var version = element.getAttribute('version');
     var value = element.text;

lib/domain/atom_item.dart

@@ -8,20 +8,20 @@ import 'package:webfeed/util/xml.dart';
 import 'package:xml/xml.dart';
 
 class AtomItem {
-  final String id;
-  final String title;
-  final DateTime updated;
+  final String? id;
+  final String? title;
+  final DateTime? updated;
 
-  final List<AtomPerson> authors;
-  final List<AtomLink> links;
-  final List<AtomCategory> categories;
-  final List<AtomPerson> contributors;
-  final AtomSource source;
-  final String published;
-  final String content;
-  final String summary;
-  final String rights;
-  final Media media;
+  final List<AtomPerson>? authors;
+  final List<AtomLink>? links;
+  final List<AtomCategory>? categories;
+  final List<AtomPerson>? contributors;
+  final AtomSource? source;
+  final String? published;
+  final String? content;
+  final String? summary;
+  final String? rights;
+  final Media? media;
 
   AtomItem({
     this.id,

lib/domain/atom_link.dart

@@ -1,11 +1,11 @@
 import 'package:xml/xml.dart';
 
 class AtomLink {
-  final String href;
-  final String rel;
-  final String type;
-  final String hreflang;
-  final String title;
+  final String? href;
+  final String? rel;
+  final String? type;
+  final String? hreflang;
+  final String? title;
   final int length;
 
   AtomLink(
@@ -25,7 +25,7 @@ class AtomLink {
     var hreflang = element.getAttribute('hreflang');
     var length = 0;
     if (element.getAttribute('length') != null) {
-      length = int.parse(element.getAttribute('length'));
+      length = int.parse(element.getAttribute('length')!);
     }
     return AtomLink(href, rel, type, hreflang, title, length);
   }

lib/domain/atom_person.dart

@@ -2,9 +2,9 @@ import 'package:webfeed/util/xml.dart';
 import 'package:xml/xml.dart';
 
 class AtomPerson {
-  final String name;
-  final String uri;
-  final String email;
+  final String? name;
+  final String? uri;
+  final String? email;
 
   AtomPerson({this.name, this.uri, this.email});
 

lib/domain/atom_source.dart

@@ -2,20 +2,18 @@ import 'package:webfeed/util/xml.dart';
 import 'package:xml/xml.dart';
 
 class AtomSource {
-  final String id;
-  final String title;
-  final String updated;
+  final String? id;
+  final String? title;
+  final String? updated;
 
   AtomSource({
     this.id,
     this.title,
     this.updated,
   });
 
-  factory AtomSource.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
+  static parse(XmlElement? element) {
+    if (element == null) return null;
     return AtomSource(
       id: findFirstElement(element, 'id')?.text,
       title: findFirstElement(element, 'title')?.text,

lib/domain/dublin_core/dublin_core.dart

@@ -3,23 +3,23 @@ import 'package:webfeed/util/xml.dart';
 import 'package:xml/xml.dart';
 
 class DublinCore {
-  final String title;
-  final String description;
-  final String creator;
-  final String subject;
-  final String publisher;
-  final String contributor;
-  final DateTime date;
-  final DateTime created;
-  final DateTime modified;
-  final String type;
-  final String format;
-  final String identifier;
-  final String source;
-  final String language;
-  final String relation;
-  final String coverage;
-  final String rights;
+  final String? title;
+  final String? description;
+  final String? creator;
+  final String? subject;
+  final String? publisher;
+  final String? contributor;
+  final DateTime? date;
+  final DateTime? created;
+  final DateTime? modified;
+  final String? type;
+  final String? format;
+  final String? identifier;
+  final String? source;
+  final String? language;
+  final String? relation;
+  final String? coverage;
+  final String? rights;
 
   DublinCore({
     this.title,
@@ -41,7 +41,7 @@ class DublinCore {
     this.rights,
   });
 
-  factory DublinCore.parse(XmlElement element) {
+  static parse(XmlElement? element) {
     if (element == null) {
       return null;
     }

lib/domain/itunes/itunes.dart

@@ -7,23 +7,23 @@ import 'package:webfeed/util/xml.dart';
 import 'package:xml/xml.dart';
 
 class Itunes {
-  final String author;
-  final String summary;
-  final bool explicit;
-  final String title;
-  final String subtitle;
-  final ItunesOwner owner;
-  final List<String> keywords;
-  final ItunesImage image;
-  final List<ItunesCategory> categories;
-  final ItunesType type;
-  final String newFeedUrl;
-  final bool block;
-  final bool complete;
-  final int episode;
-  final int season;
-  final Duration duration;
-  final ItunesEpisodeType episodeType;
+  final String? author;
+  final String? summary;
+  final bool? explicit;
+  final String? title;
+  final String? subtitle;
+  final ItunesOwner? owner;
+  final List<String>? keywords;
+  final ItunesImage? image;
+  final List<ItunesCategory?>? categories;
+  final ItunesType? type;
+  final String? newFeedUrl;
+  final bool? block;
+  final bool? complete;
+  final int? episode;
+  final int? season;
+  final Duration? duration;
+  final ItunesEpisodeType? episodeType;
 
   Itunes({
     this.author,
@@ -45,7 +45,7 @@ class Itunes {
     this.episodeType,
   });
 
-  factory Itunes.parse(XmlElement element) {
+  static parse(XmlElement? element) {
     if (element == null) {
       return null;
     }
@@ -61,12 +61,12 @@ class Itunes {
       owner: ItunesOwner.parse(findFirstElement(element, 'itunes:owner')),
       keywords: findFirstElement(element, 'itunes:keywords')
               ?.text
-              ?.split(',')
-              ?.map((keyword) => keyword.trim())
-              ?.toList() ??
+              .split(',')
+              .map((keyword) => keyword.trim())
+              .toList() ??
           [],
       image: ItunesImage.parse(findFirstElement(element, 'itunes:image')),
-      categories: findElements(element, 'itunes:category')
+      categories: findElements(element, 'itunes:category')!
           .map((e) => ItunesCategory.parse(e))
           .toList(),
       type: newItunesType(findFirstElement(element, 'itunes:type')),

lib/domain/itunes/itunes_category.dart

@@ -1,20 +1,18 @@
 import 'package:xml/xml.dart';
 
 class ItunesCategory {
-  final String category;
-  final List<String> subCategories;
+  final String? category;
+  final List<String?>? subCategories;
 
   ItunesCategory({this.category, this.subCategories});
 
-  factory ItunesCategory.parse(XmlElement element) {
+  static ItunesCategory? parse(XmlElement? element) {
     if (element == null) return null;
     return ItunesCategory(
-      category: element.getAttribute('text')?.trim(),
-      subCategories: element
-              .findElements('itunes:category')
-              ?.map((e) => e.getAttribute('text')?.trim())
-              ?.toList() ??
-          [],
-    );
+        category: element.getAttribute('text')?.trim(),
+        subCategories: element
+            .findElements('itunes:category')
+            .map((e) => e.getAttribute('text')?.trim())
+            .toList());
   }
 }

lib/domain/itunes/itunes_episode_type.dart

@@ -2,7 +2,7 @@ import 'package:xml/xml.dart';
 
 enum ItunesEpisodeType { full, trailer, bonus, unknown }
 
-ItunesEpisodeType newItunesEpisodeType(XmlElement element) {
+ItunesEpisodeType newItunesEpisodeType(XmlElement? element) {
   switch (element?.text) {
     case 'full':
       return ItunesEpisodeType.full;

lib/domain/itunes/itunes_image.dart

@@ -1,14 +1,17 @@
 import 'package:xml/xml.dart';
 
 class ItunesImage {
-  final String href;
+  final String? href;
 
   ItunesImage({this.href});
 
-  factory ItunesImage.parse(XmlElement element) {
+  static parse(XmlElement? element) {
+    ItunesImage? result;
     if (element == null) return null;
-    return ItunesImage(
+    result = ItunesImage(
       href: element.getAttribute('href')?.trim(),
     );
+
+    return result;
   }
 }

lib/domain/itunes/itunes_owner.dart

@@ -2,16 +2,15 @@ import 'package:webfeed/util/xml.dart';
 import 'package:xml/xml.dart';
 
 class ItunesOwner {
-  final String name;
-  final String email;
+  final String? name;
+  final String? email;
 
   ItunesOwner({this.name, this.email});
 
-  factory ItunesOwner.parse(XmlElement element) {
-    if (element == null) return null;
+  factory ItunesOwner.parse(XmlElement? element) {
     return ItunesOwner(
-      name: findFirstElement(element, 'itunes:name')?.text?.trim(),
-      email: findFirstElement(element, 'itunes:email')?.text?.trim(),
+      name: findFirstElement(element, 'itunes:name')?.text.trim(),
+      email: findFirstElement(element, 'itunes:email')?.text.trim(),
     );
   }
 }

lib/domain/itunes/itunes_type.dart

@@ -2,7 +2,7 @@ import 'package:xml/xml.dart';
 
 enum ItunesType { episodic, serial, unknown }
 
-ItunesType newItunesType(XmlElement element) {
+ItunesType newItunesType(XmlElement? element) {
   switch (element?.text) {
     case 'episodic':
       return ItunesType.episodic;