Allow a cookie without a domain to be set on Android

The other CookieManager implementations in Flutter allow for no domain,
as the Android CookieManager implementation. By providing a default
domain, applications cannot opt-out of the default
CookieManager.setCookie behaviour (which prepends a "period" to the
domain), which is treated as a different domain by Webkit on Android.
This leads to multiple cookies for the same URL if the server serves a
cookie without a domain, or with a domain that does not contain a
leading period.

Note, iOS's setCookie doesn't take a url parameter (at least in the way
it's called from flutter_inappwebview) and instead this is passed an
attribute on the HTTPCookie object itself (originURL). When constructing
a HTTPCookie you must supply either originURL OR domain. Both a
permitted, but at least one must be present. [1]

By making domain optional, without a default, on both platforms,
consumers can now set cookies that don't use the domain attribute but
still allows for setting a domain when required.

[1] https://developer.apple.com/documentation/foundation/httpcookie/1392975-init

android/src/main/java/com/pichillilorenzo/flutter_inappwebview/MyCookieManager.java

@@ -140,7 +140,10 @@ public class MyCookieManager implements MethodChannel.MethodCallHandler {
     cookieManager = getCookieManager();
     if (cookieManager == null) return;
 
-    String cookieValue = name + "=" + value + "; Domain=" + domain + "; Path=" + path;
+    String cookieValue = name + "=" + value + "; Path=" + path;
+
+    if (domain != null)
+      cookieValue += "; Domain=" + domain;
 
     if (expiresDate != null)
       cookieValue += "; Expires=" + getCookieExpirationDate(expiresDate);

ios/Classes/MyCookieManager.swift

@@ -35,7 +35,6 @@ class MyCookieManager: NSObject, FlutterPlugin {
                 let url = arguments!["url"] as! String
                 let name = arguments!["name"] as! String
                 let value = arguments!["value"] as! String
-                let domain = arguments!["domain"] as! String
                 let path = arguments!["path"] as! String
                 
                 var expiresDate: Int64?
@@ -47,12 +46,13 @@ class MyCookieManager: NSObject, FlutterPlugin {
                 let isSecure = arguments!["isSecure"] as? Bool
                 let isHttpOnly = arguments!["isHttpOnly"] as? Bool
                 let sameSite = arguments!["sameSite"] as? String
+                let domain = arguments!["domain"] as? String
                 
                 MyCookieManager.setCookie(url: url,
                                           name: name,
                                           value: value,
-                                          domain: domain,
                                           path: path,
+                                          domain: domain,
                                           expiresDate: expiresDate,
                                           maxAge: maxAge,
                                           isSecure: isSecure,
@@ -92,8 +92,8 @@ class MyCookieManager: NSObject, FlutterPlugin {
     public static func setCookie(url: String,
                           name: String,
                           value: String,
-                          domain: String,
                           path: String,
+                          domain: String?,
                           expiresDate: Int64?,
                           maxAge: Int64?,
                           isSecure: Bool?,
@@ -109,8 +109,12 @@ class MyCookieManager: NSObject, FlutterPlugin {
         properties[.originURL] = url
         properties[.name] = name
         properties[.value] = value
-        properties[.domain] = domain
         properties[.path] = path
+        
+        if domain != nil {
+            properties[.domain] = domain
+        }
+
         if expiresDate != nil {
             // convert from milliseconds
             properties[.expires] = Date(timeIntervalSince1970: TimeInterval(Double(expiresDate!)/1000))

lib/src/cookie_manager.dart

@@ -63,12 +63,9 @@ class CookieManager {
       bool? isHttpOnly,
       HTTPCookieSameSitePolicy? sameSite,
       InAppWebViewController? iosBelow11WebViewController}) async {
-    if (domain == null) domain = _getDomainName(url);
-
     assert(url.toString().isNotEmpty);
     assert(name.isNotEmpty);
     assert(value.isNotEmpty);
-    assert(domain.isNotEmpty);
     assert(path.isNotEmpty);
 
     if (defaultTargetPlatform == TargetPlatform.iOS) {
@@ -109,15 +106,16 @@ class CookieManager {
       {required Uri url,
       required String name,
       required String value,
-      required String domain,
       String path = "/",
+      String? domain,
       int? expiresDate,
       int? maxAge,
       bool? isSecure,
       HTTPCookieSameSitePolicy? sameSite,
       InAppWebViewController? webViewController}) async {
-    var cookieValue =
-        name + "=" + value + "; Domain=" + domain + "; Path=" + path;
+    var cookieValue = name + "=" + value + "; Path=" + path;
+
+    if (domain != null) cookieValue += "; Domain=" + domain;
 
     if (expiresDate != null)
       cookieValue += "; Expires=" + await _getCookieExpirationDate(expiresDate);