#758 CookieJar persistence

Test/Flurl.Test/Http/CookieTests.cs

@@ -86,6 +86,50 @@ public async Task can_send_and_receive_cookies_with_jar_initialized() {
 			Assert.AreEqual(1, jar.Count(c => c.Name == "y" && c.Value == "bazz"));
 		}
 
+		[Test]
+		public void can_build_response_header() {
+			// simple
+			var cookie1 = new FlurlCookie("x", "foo");
+			Assert.AreEqual("x=foo", CookieCutter.BuildResponseHeader(cookie1));
+
+			// complex
+			var cookie = new FlurlCookie("y", "bar") {
+				Domain = "cookie.org",
+				Expires = new DateTimeOffset(2025, 12, 31, 1, 23, 45, TimeSpan.Zero),
+				HttpOnly = true,
+				MaxAge = 10,
+				Path = "/a/b",
+				Secure = true,
+				SameSite = SameSite.Lax
+			};
+			var headerVal = CookieCutter.BuildResponseHeader(cookie);
+			Assert.AreEqual("y=bar; Domain=cookie.org; Expires=Wed, 31 Dec 2025 01:23:45 GMT; HttpOnly; Max-Age=10; Path=/a/b; Secure; SameSite=Lax", headerVal);
+		}
+
+		[Test]
+		public void can_perist_and_load_jar() {
+			var jar1 = new CookieJar()
+				.AddOrReplace("x", "foo", "https://site1.com", DateTimeOffset.UtcNow)
+				.AddOrReplace("y", "bar", "https://site2.com", DateTimeOffset.UtcNow.AddMinutes(-10));
+
+			var s1 = jar1.ToString();
+
+			var jar2 = CookieJar.LoadFromString(s1);
+			Assert.AreEqual(jar1.Count, jar2.Count);
+
+			var cookies1 = jar1.ToArray();
+			var cookies2 = jar2.ToArray();
+
+			for (var i = 0; i < 2; i++) {
+				Assert.AreEqual(cookies1[i].Name, cookies2[i].Name);
+				Assert.AreEqual(cookies1[i].Value, cookies2[i].Value);
+				Assert.AreEqual(cookies1[i].OriginUrl, cookies2[i].OriginUrl);
+			}
+
+			var s2 = jar2.ToString();
+			Assert.AreEqual(s1, s2);
+		}
+
 		[Test]
 		public async Task can_do_cookie_session() {
 			HttpTest
@@ -114,7 +158,7 @@ public async Task can_do_cookie_session() {
 		[Test]
 		public void can_parse_set_cookie_header() {
 			var start = DateTimeOffset.UtcNow;
-			var cookie = CookieCutter.ParseResponseHeader("https://www.cookies.com/a/b", "x=foo  ; DoMaIn=cookies.com  ;     path=/  ; MAX-AGE=999 ; expires= ;  secure ;HTTPONLY ;samesite=none");
+			var cookie = CookieCutter.ParseResponseHeader("x=foo  ; DoMaIn=cookies.com  ;     path=/  ; MAX-AGE=999 ; expires= ;  secure ;HTTPONLY ;samesite=none", "https://www.cookies.com/a/b");
 			Assert.AreEqual("https://www.cookies.com/a/b", cookie.OriginUrl.ToString());
 			Assert.AreEqual("x", cookie.Name);
 			Assert.AreEqual("foo", cookie.Value);
@@ -130,7 +174,7 @@ public void can_parse_set_cookie_header() {
 
 			// simpler case
 			start = DateTimeOffset.UtcNow;
-			cookie = CookieCutter.ParseResponseHeader("https://www.cookies.com/a/b", "y=bar");
+			cookie = CookieCutter.ParseResponseHeader("y=bar", "https://www.cookies.com/a/b");
 			Assert.AreEqual("https://www.cookies.com/a/b", cookie.OriginUrl.ToString());
 			Assert.AreEqual("y", cookie.Name);
 			Assert.AreEqual("bar", cookie.Value);
@@ -164,7 +208,7 @@ public void cannot_change_cookie_after_adding_to_jar() {
 
 		[Test]
 		public void unquotes_cookie_value() {
-			var cookie = CookieCutter.ParseResponseHeader("https://cookies.com", "x=\"hello there\"" );
+			var cookie = CookieCutter.ParseResponseHeader("x=\"hello there\"", "https://cookies.com");
 			Assert.AreEqual("hello there", cookie.Value);
 		}
 

src/Flurl.Http/CookieCutter.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Text;
 using Flurl.Util;
 
 namespace Flurl.Http
@@ -25,23 +26,24 @@ public static class CookieCutter
 		/// <summary>
 		/// Parses a Set-Cookie response header to a FlurlCookie.
 		/// </summary>
-		/// <param name="url">The URL that sent the response.</param>
 		/// <param name="headerValue">Value of the Set-Cookie header.</param>
+		/// <param name="url">The URL that sent the response.</param>
+		/// <param name="dateReceived">Date/time that original Set-Cookie header was received. Defaults to current date/time. Important for Max-Age to be enforced correctly.</param>
 		/// <returns></returns>
-		public static FlurlCookie ParseResponseHeader(string url, string headerValue) {
+		public static FlurlCookie ParseResponseHeader(string headerValue, string url, DateTimeOffset? dateReceived = null) {
 			if (string.IsNullOrEmpty(headerValue)) return null;
 
 			FlurlCookie cookie = null;
 			foreach (var pair in GetPairs(headerValue)) {
 				if (cookie == null)
-					cookie = new FlurlCookie(pair.Name, pair.Value.Trim('"'), url, DateTimeOffset.UtcNow);
+					cookie = new FlurlCookie(pair.Name, pair.Value.Trim('"'), url, dateReceived ?? DateTimeOffset.UtcNow);
 
 				// ordinal string compare is both safest and fastest
 				// https://docs.microsoft.com/en-us/dotnet/standard/base-types/best-practices-strings#recommendations-for-string-usage
 				else if (pair.Name.OrdinalEquals("Expires", true))
-					cookie.Expires = DateTimeOffset.TryParse(pair.Value, out var d) ? d : (DateTimeOffset?)null;
+					cookie.Expires = DateTimeOffset.TryParse(pair.Value, out var d) ? d : null;
 				else if (pair.Name.OrdinalEquals("Max-Age", true))
-					cookie.MaxAge = int.TryParse(pair.Value, out var i) ? i : (int?)null;
+					cookie.MaxAge = int.TryParse(pair.Value, out var i) ? i : null;
 				else if (pair.Name.OrdinalEquals("Domain", true))
 					cookie.Domain = pair.Value;
 				else if (pair.Name.OrdinalEquals("Path", true))
@@ -51,7 +53,7 @@ public static FlurlCookie ParseResponseHeader(string url, string headerValue) {
 				else if (pair.Name.OrdinalEquals("Secure", true))
 					cookie.Secure = true;
 				else if (pair.Name.OrdinalEquals("SameSite", true))
-					cookie.SameSite = Enum.TryParse<SameSite>(pair.Value, true, out var val) ? val : (SameSite?)null;
+					cookie.SameSite = Enum.TryParse<SameSite>(pair.Value, true, out var val) ? val : null;
 			}
 			return cookie;
 		}
@@ -68,13 +70,33 @@ public static FlurlCookie ParseResponseHeader(string url, string headerValue) {
 		/// Creates a Cookie request header value from a list of cookie name-value pairs.
 		/// </summary>
 		/// <returns>A header value if cookie values are present, otherwise null.</returns>
-		public static string ToRequestHeader(IEnumerable<(string Name, string Value)> cookies) {
+		public static string BuildRequestHeader(IEnumerable<(string Name, string Value)> cookies) {
 			if (cookies?.Any() != true) return null;
 
 			return string.Join("; ", cookies.Select(c =>
 				$"{c.Name}={c.Value}"));
 		}
 
+		/// <summary>
+		/// Creates a Set-Cookie response header value from a FlurlCookie.
+		/// </summary>
+		/// <returns>A header value if cookie is non-null, otherwise null.</returns>
+		public static string BuildResponseHeader(FlurlCookie cookie) {
+			if (cookie == null) return null;
+
+			StringBuilder result = new StringBuilder();
+			result.Append($"{cookie.Name}={cookie.Value}");
+			if (cookie.Domain != null) result.Append($"; Domain={cookie.Domain}");
+			if (cookie.Expires != null) result.Append($"; Expires={cookie.Expires:r}");
+			if (cookie.HttpOnly) result.Append("; HttpOnly");
+			if (cookie.MaxAge != null) result.Append($"; Max-Age={cookie.MaxAge}");
+			if (cookie.Path != null) result.Append($"; Path={cookie.Path}");
+			if (cookie.Secure) result.Append("; Secure");
+			if (cookie.SameSite != null) result.Append($"; SameSite={cookie.SameSite}");
+
+			return result.ToString();
+		}
+
 		/// <summary>
 		/// True if this cookie passes well-accepted rules for the Set-Cookie header. If false, provides a descriptive reason.
 		/// </summary>

src/Flurl.Http/CookieExtensions.cs

@@ -19,7 +19,7 @@ public static class CookieExtensions
 		public static IFlurlRequest WithCookie(this IFlurlRequest request, string name, object value) {
 			var cookies = new NameValueList<string>(request.Cookies, true); // cookie names are case-sensitive https://stackoverflow.com/a/11312272/62600
 			cookies.AddOrReplace(name, value.ToInvariantString());
-			return request.WithHeader("Cookie", CookieCutter.ToRequestHeader(cookies));
+			return request.WithHeader("Cookie", CookieCutter.BuildRequestHeader(cookies));
 		}
 
 		/// <summary>
@@ -40,7 +40,7 @@ public static IFlurlRequest WithCookies(this IFlurlRequest request, object value
 				foreach (var kv in group.Skip(1))
 					cookies.Add(kv.Key, kv.Value.ToInvariantString());
 			}
-			return request.WithHeader("Cookie", CookieCutter.ToRequestHeader(cookies));
+			return request.WithHeader("Cookie", CookieCutter.BuildRequestHeader(cookies));
 		}
 
 		/// <summary>

src/Flurl.Http/CookieJar.cs

@@ -2,6 +2,7 @@
 using System.Collections;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using Flurl.Util;
 
@@ -77,6 +78,42 @@ public CookieJar Clear() {
 			return this;
 		}
 
+		/// <summary>
+		/// Writes this CookieJar to a TextWriter. Useful for persisting to a file.
+		/// </summary>
+		public void WriteTo(TextWriter writer) {
+			foreach (var cookie in _dict.Values)
+				cookie.WriteTo(writer);
+		}
+
+		/// <summary>
+		/// Instantiates a CookieJar that was previously persisted using WriteTo.
+		/// </summary>
+		public static CookieJar LoadFrom(TextReader reader) {
+			if (reader == null) return null;
+			var jar = new CookieJar();
+			while (reader.Peek() >= 0) {
+				var cookie = FlurlCookie.LoadFrom(reader);
+				if (cookie != null)
+					jar.AddOrReplace(cookie);
+			}
+			return jar;
+		}
+
+		/// <summary>
+		/// Returns a string representing this CookieJar.
+		/// </summary>
+		public override string ToString() {
+			var writer = new StringWriter();
+			WriteTo(writer);
+			return writer.ToString();
+		}
+
+		/// <summary>
+		/// Instantiates a CookieJar that was previously persisted using ToString.
+		/// </summary>
+		public static CookieJar LoadFromString(string s) => LoadFrom(new StringReader(s));
+
 		/// <inheritdoc/>
 		public IEnumerator<FlurlCookie> GetEnumerator() => _dict.Values.GetEnumerator();
 

src/Flurl.Http/FlurlCookie.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
 using System.Runtime.CompilerServices;
 
 namespace Flurl.Http
@@ -145,6 +147,46 @@ public string GetKey() {
 			return $"{domain}{path}:{Name}";
 		}
 
+		/// <summary>
+		/// Writes this cookie to a TextWriter. Useful for persisting to a file.
+		/// </summary>
+		public void WriteTo(TextWriter writer) {
+			writer.WriteLine(DateReceived.ToString("s"));
+			writer.WriteLine(OriginUrl);
+			writer.WriteLine(CookieCutter.BuildResponseHeader(this));
+		}
+
+		/// <summary>
+		/// Instantiates a FlurlCookie that was previously persisted using WriteTo.
+		/// </summary>
+		public static FlurlCookie LoadFrom(TextReader reader) {
+			if (!DateTimeOffset.TryParse(reader?.ReadLine(), null, DateTimeStyles.AssumeUniversal, out var received))
+				return null;
+
+			var url = reader.ReadLine();
+			if (string.IsNullOrEmpty(url)) return null;
+
+			var headerVal = reader.ReadLine();
+			if (string.IsNullOrEmpty(headerVal)) return null;
+
+			return CookieCutter.ParseResponseHeader(headerVal, url, received);
+		}
+
+		/// <summary>
+		/// Returns a string representing this FlurlCookie.
+		/// </summary>
+		public override string ToString() {
+			var writer = new StringWriter();
+			WriteTo(writer);
+			return writer.ToString();
+		}
+
+		/// <summary>
+		/// Instantiates a FlurlCookie that was previously persisted using ToString.
+		/// </summary>
+		public static FlurlCookie LoadFromString(string s) => LoadFrom(new StringReader(s));
+
+
 		/// <summary>
 		/// Makes this cookie immutable. Call when added to a jar.
 		/// </summary>

src/Flurl.Http/FlurlResponse.cs

@@ -118,7 +118,7 @@ private IReadOnlyNameValueList<string> LoadHeaders() {
 		private IReadOnlyList<FlurlCookie> LoadCookies() {
 			var url = ResponseMessage.RequestMessage.RequestUri.AbsoluteUri;
 			return ResponseMessage.Headers.TryGetValues("Set-Cookie", out var headerValues) ?
-				headerValues.Select(hv => CookieCutter.ParseResponseHeader(url, hv)).ToList() :
+				headerValues.Select(hv => CookieCutter.ParseResponseHeader(hv, url)).ToList() :
 				new List<FlurlCookie>();
 		}