Add registration API call and related error handling

osu.Game/Online/API/APIAccess.cs

@@ -5,7 +5,9 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Net;
+using System.Net.Http;
 using System.Threading;
+using Newtonsoft.Json.Linq;
 using osu.Framework.Configuration;
 using osu.Framework.Graphics;
 using osu.Framework.Logging;
@@ -189,13 +191,37 @@ namespace osu.Game.Online.API
             this.password = password;
         }
 
-        public void CreateAccount(string email, string username, string password)
+        public RegistrationRequest.RegistrationRequestErrors CreateAccount(string email, string username, string password)
         {
             Debug.Assert(State == APIState.Offline);
 
-            var req = new RegistrationRequest();
+            var req = new RegistrationRequest
+            {
+                Url = $@"{Endpoint}/users",
+                Method = HttpMethod.Post,
+                Username = username,
+                Email = email,
+                Password = password
+            };
 
-            req.Perform();
+            try
+            {
+                req.Perform();
+            }
+            catch (Exception e)
+            {
+                try
+                {
+                    return JObject.Parse(req.ResponseString).SelectToken("form_error", true).ToObject<RegistrationRequest.RegistrationRequestErrors>();
+                }
+                catch
+                {
+                    // if we couldn't deserialize the error message let's throw the original exception outwards.
+                    throw e;
+                }
+            }
+
+            return null;
         }
 
         /// <summary>

osu.Game/Online/API/RegsitrationRequest.cs

@@ -1,11 +1,12 @@
 // Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using Newtonsoft.Json;
 using osu.Framework.IO.Network;
 
 namespace osu.Game.Online.API
 {
-    internal class RegsitrationRequest : JsonWebRequest<OAuthToken>
+    public class RegistrationRequest : WebRequest
     {
         internal string Username;
         internal string Email;
@@ -13,11 +14,28 @@ namespace osu.Game.Online.API
 
         protected override void PrePerform()
         {
-            AddParameter("user", Username);
+            AddParameter("user[username]", Username);
-            AddParameter("user_email", Email);
+            AddParameter("user[user_email]", Email);
-            AddParameter("password", Password);
+            AddParameter("user[password]", Password);
 
             base.PrePerform();
         }
+
+        public class RegistrationRequestErrors
+        {
+            public UserErrors User;
+
+            public class UserErrors
+            {
+                [JsonProperty("username")]
+                public string[] Username;
+
+                [JsonProperty("user_email")]
+                public string[] Email;
+
+                [JsonProperty("password")]
+                public string[] Password;
+            }
+        }
     }
 }

osu.Game/Overlays/AccountCreation/ErrorTextFlowContainer.cs

@@ -0,0 +1,35 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System.Collections.Generic;
+using osu.Framework.Graphics;
+using osu.Game.Graphics.Containers;
+using osuTK.Graphics;
+
+namespace osu.Game.Overlays.AccountCreation
+{
+    public class ErrorTextFlowContainer : OsuTextFlowContainer
+    {
+        private readonly List<Drawable> errorDrawables = new List<Drawable>();
+
+        public ErrorTextFlowContainer()
+            : base(cp => { cp.TextSize = 12; })
+        {
+        }
+
+        public void ClearErrors()
+        {
+            errorDrawables.ForEach(d => d.Expire());
+        }
+
+        public void AddErrors(string[] errors)
+        {
+            ClearErrors();
+
+            if (errors == null) return;
+
+            foreach (var error in errors)
+                errorDrawables.AddRange(AddParagraph(error, cp => cp.Colour = Color4.Red));
+        }
+    }
+}

osu.Game/Overlays/AccountCreationOverlay.cs

@@ -1,7 +1,9 @@
 // Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using System;
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using osu.Framework.Allocation;
 using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Extensions.IEnumerableExtensions;
@@ -24,9 +26,9 @@ namespace osu.Game.Overlays
 {
     public class AccountCreationOverlay : OsuFocusedOverlayContainer, IOnlineComponent
     {
-        private OsuTextFlowContainer usernameDescription;
+        private ErrorTextFlowContainer usernameDescription;
-        private OsuTextFlowContainer emailAddressDescription;
+        private ErrorTextFlowContainer emailAddressDescription;
-        private OsuTextFlowContainer passwordDescription;
+        private ErrorTextFlowContainer passwordDescription;
 
         private OsuTextBox usernameTextBox;
         private OsuTextBox emailTextBox;
@@ -43,8 +45,6 @@ namespace osu.Game.Overlays
             Size = new Vector2(620, 450);
             Anchor = Anchor.Centre;
             Origin = Anchor.Centre;
-
-            State = Visibility.Visible;
         }
 
         [BackgroundDependencyLoader]
@@ -114,9 +114,10 @@ namespace osu.Game.Overlays
                                             RelativeSizeAxes = Axes.X,
                                             TabbableContentContainer = this
                                         },
-                                        usernameDescription = new OsuTextFlowContainer(cp => { cp.TextSize = 12; })
+                                        usernameDescription = new ErrorTextFlowContainer
                                         {
-                                            RelativeSizeAxes = Axes.X, AutoSizeAxes = Axes.Y
+                                            RelativeSizeAxes = Axes.X,
+                                            AutoSizeAxes = Axes.Y
                                         },
                                         emailTextBox = new OsuTextBox
                                         {
@@ -125,9 +126,10 @@ namespace osu.Game.Overlays
                                             Text = api.ProvidedUsername ?? string.Empty,
                                             TabbableContentContainer = this
                                         },
-                                        emailAddressDescription = new OsuTextFlowContainer(cp => { cp.TextSize = 12; })
+                                        emailAddressDescription = new ErrorTextFlowContainer
                                         {
-                                            RelativeSizeAxes = Axes.X, AutoSizeAxes = Axes.Y
+                                            RelativeSizeAxes = Axes.X,
+                                            AutoSizeAxes = Axes.Y
                                         },
                                         passwordTextBox = new OsuPasswordTextBox
                                         {
@@ -135,9 +137,10 @@ namespace osu.Game.Overlays
                                             RelativeSizeAxes = Axes.X,
                                             TabbableContentContainer = this,
                                         },
-                                        passwordDescription = new OsuTextFlowContainer(cp => { cp.TextSize = 12; })
+                                        passwordDescription = new ErrorTextFlowContainer
                                         {
-                                            RelativeSizeAxes = Axes.X, AutoSizeAxes = Axes.Y
+                                            RelativeSizeAxes = Axes.X,
+                                            AutoSizeAxes = Axes.Y
                                         },
                                         new Container
                                         {
@@ -175,9 +178,7 @@ namespace osu.Game.Overlays
             characterCheckText = passwordDescription.AddText("8 characters long");
             passwordDescription.AddText(". Choose something long but also something you will remember, like a line from your favourite song.");
 
-            passwordTextBox.Current.ValueChanged += text => {
+            passwordTextBox.Current.ValueChanged += text => { characterCheckText.ForEach(s => s.Colour = text.Length == 0 ? Color4.White : Interpolation.ValueAt(text.Length, Color4.OrangeRed, Color4.YellowGreen, 0, 8, Easing.In)); };
-                characterCheckText.ForEach(s => s.Colour = text.Length == 0 ? Color4.White : Interpolation.ValueAt(text.Length, Color4.OrangeRed, Color4.YellowGreen, 0, 8, Easing.In));
-            };
         }
 
         private void performRegistration()
@@ -191,7 +192,47 @@ namespace osu.Game.Overlays
                 return;
             }
 
-            api.CreateAccount(emailTextBox.Text, usernameTextBox.Text, passwordTextBox.Text);
+            usernameDescription.ClearErrors();
+            emailAddressDescription.ClearErrors();
+            passwordDescription.ClearErrors();
+
+            Task.Run(() =>
+            {
+                bool success;
+                RegistrationRequest.RegistrationRequestErrors errors = null;
+
+                try
+                {
+                    errors = api.CreateAccount(emailTextBox.Text, usernameTextBox.Text, passwordTextBox.Text);
+                    success = errors == null;
+                }
+                catch (Exception)
+                {
+                    success = false;
+                }
+
+                Schedule(() =>
+                {
+                    if (!success)
+                    {
+                        if (errors != null)
+                        {
+                            usernameDescription.AddErrors(errors.User.Username);
+                            emailAddressDescription.AddErrors(errors.User.Email);
+                            passwordDescription.AddErrors(errors.User.Password);
+                        }
+                        else
+                        {
+                            passwordDescription.AddErrors(new[] { "Something happened... but we're not sure what." });
+                        }
+
+                        registerShake.Shake();
+                        return;
+                    }
+
+                    api.Login(emailTextBox.Text, passwordTextBox.Text);
+                });
+            });
         }
 
         private OsuTextBox nextUnfilledTextbox()