Add CookieContainer.GetAllCookies

src/libraries/System.Net.Primitives/ref/System.Net.Primitives.cs

@@ -83,6 +83,7 @@ public void Add(System.Uri uri, System.Net.Cookie cookie) { }
         public void Add(System.Uri uri, System.Net.CookieCollection cookies) { }
         public string GetCookieHeader(System.Uri uri) { throw null; }
         public System.Net.CookieCollection GetCookies(System.Uri uri) { throw null; }
+        public System.Net.CookieCollection GetAllCookies() { throw null; }
         public void SetCookies(System.Uri uri, string cookieHeader) { }
     }
     public partial class CookieException : System.FormatException, System.Runtime.Serialization.ISerializable

src/libraries/System.Net.Primitives/src/System/Net/CookieContainer.cs

@@ -787,6 +787,32 @@ public CookieCollection GetCookies(Uri uri)
             return InternalGetCookies(uri) ?? new CookieCollection();
         }
 
+        /// <summary>Gets a <see cref="CookieCollection"/> that contains all of the <see cref="Cookie"/> instances in the container.</summary>
+        /// <returns>A <see cref="CookieCollection"/> that contains all of the <see cref="Cookie"/> instances in the container.</returns>
+        public CookieCollection GetAllCookies()
+        {
+            var result = new CookieCollection();
+
+            lock (m_domainTable.SyncRoot)
+            {
+                IDictionaryEnumerator lists = m_domainTable.GetEnumerator();
+                while (lists.MoveNext())
+                {
+                    PathList list = (PathList)lists.Value!;
+                    lock (list.SyncRoot)
+                    {
+                        IDictionaryEnumerator collections = list.List.GetEnumerator();
+                        while (collections.MoveNext())
+                        {
+                            result.Add((CookieCollection)collections.Value!);
+                        }
+                    }
+                }
+            }
+
+            return result;
+        }
+
         internal CookieCollection? InternalGetCookies(Uri uri)
         {
             if (m_count == 0)

src/libraries/System.Net.Primitives/tests/FunctionalTests/CookieTest/CookieContainerTest.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Linq;
 using Xunit;
 
 namespace System.Net.Primitives.Functional.Tests
@@ -124,5 +125,37 @@ public void GetCookies_AddCookieVersion1WithExplicitDomain_CookieReturnedForDoma
             cookies = container.GetCookies(uri);
             Assert.Equal(0, cookies.Count);
         }
+
+        [Fact]
+        public void GetAllCookies_Empty_ReturnsEmptyCollection()
+        {
+            var container = new CookieContainer();
+            Assert.NotNull(container.GetAllCookies());
+            Assert.NotSame(container.GetAllCookies(), container.GetAllCookies());
+            Assert.Empty(container.GetAllCookies());
+        }
+
+        [Fact]
+        public void GetAllCookies_NonEmpty_AllCookiesReturned()
+        {
+            var container = new CookieContainer();
+            container.PerDomainCapacity = 100;
+            container.Capacity = 100;
+
+            Cookie[] cookies = Enumerable.Range(0, 100).Select(i => new Cookie($"name{i}", $"value{i}")).ToArray();
+
+            Uri[] uris = new[] { new Uri("https://dot.net"), new Uri("https://source.dot.net"), new Uri("https://microsoft.com") };
+            for (int i = 0; i < cookies.Length; i++)
+            {
+                container.Add(uris[i % uris.Length], cookies[i]);
+            }
+
+            CookieCollection actual = container.GetAllCookies();
+            Assert.Equal(cookies.Length, actual.Count);
+
+            Assert.Equal(
+                cookies.Select(c => c.Name + "=" + c.Value).ToHashSet(),
+                actual.Select(c => c.Name + "=" + c.Value).ToHashSet());
+        }
     }
 }