Fixed url validation to be neater and not utilize IsWellFormatted (#66)

* Error handling on URL additions in embeds and components.

* Wording on exception comment

* Wording on exceptions

* changed IsWellFormatted to validating urls start with protocol. May not keep all url validation, may just keep image-based url validation as those definitely only require http/s.

* Helper utility made for url validation

* xml

Co-authored-by: Quin Lynch <49576606+quinchs@users.noreply.github.com>

src/Discord.Net.Core/Discord.Net.Core.xml

@@ -11643,5 +11643,13 @@
             <exception cref="T:System.ArgumentNullException"> Thrown when the supplied token string is <c>null</c>, empty, or contains only whitespace.</exception>
             <exception cref="T:System.ArgumentException"> Thrown when the supplied <see cref="T:Discord.TokenType"/> or token value is invalid. </exception>
         </member>
+        <member name="M:Discord.Utils.UrlValidation.Validate(System.String)">
+            <summary>
+            Not full URL validation right now. Just ensures protocol is present and that it's either http or https
+            </summary>
+            <param name="url">url to validate before sending to Discord</param>
+            <exception cref="T:System.InvalidOperationException">A URL must include a protocol (http or https).</exception>
+            <returns>true if url is valid by our standard, false if null, throws an error upon invalid </returns>
+        </member>
     </members>
 </doc>

src/Discord.Net.Core/Entities/Interactions/Message Components/ComponentBuilder.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Discord.Utils;
 
 namespace Discord
 {
@@ -535,12 +536,11 @@ namespace Discord
 
             if (this.Style == ButtonStyle.Link)
             {
-                    if (string.IsNullOrEmpty(this.Url))
-                        throw new InvalidOperationException("Link buttons must have a link associated with them");
-                    else if (!Uri.IsWellFormedUriString(this.Url, UriKind.Absolute))
-                        throw new InvalidOperationException("Urls must be well formatted and include their protocol (either HTTP or HTTPS)");
-            }
-            
+                if (string.IsNullOrEmpty(this.Url))
+                    throw new InvalidOperationException("Link buttons must have a link associated with them");
+                else
+                    UrlValidation.Validate(this.Url); 
+            }       
             else if (string.IsNullOrEmpty(this.CustomId))
                 throw new InvalidOperationException("Non-link buttons must have a custom id associated with them");
 

src/Discord.Net.Core/Entities/Messages/EmbedBuilder.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
+using Discord.Utils;
 
 namespace Discord
 {
@@ -401,25 +402,29 @@ namespace Discord
         ///     The built embed object.
         /// </returns>
         /// <exception cref="InvalidOperationException">Total embed length exceeds <see cref="MaxEmbedLength"/>.</exception>
-        /// <exception cref="InvalidOperationException">Any Url must be well formatted include its protocols (i.e http:// or https://).</exception>
+        /// <exception cref="InvalidOperationException">Any Url must include its protocols (i.e http:// or https://).</exception>
         public Embed Build()
         {
             if (Length > MaxEmbedLength)
                 throw new InvalidOperationException($"Total embed length must be less than or equal to {MaxEmbedLength}.");
-            if (!string.IsNullOrEmpty(Url) && !Uri.IsWellFormedUriString(Url, UriKind.Absolute))
-                throw new InvalidOperationException("Url must be well formatted and include its protocol (either HTTP or HTTPS)");
-            if (!string.IsNullOrEmpty(ThumbnailUrl) && !Uri.IsWellFormedUriString(ThumbnailUrl, UriKind.Absolute))
-                throw new InvalidOperationException("Thumbnail Url must be well formatted and include its protocol (either HTTP or HTTPS)");
-            if (!string.IsNullOrEmpty(ImageUrl) && !Uri.IsWellFormedUriString(ImageUrl, UriKind.Absolute))
-                throw new InvalidOperationException("Image Url must be well formatted and include its protocol (either HTTP or HTTPS)");
+            if (!string.IsNullOrEmpty(Url))
+                UrlValidation.Validate(Url);
+            if (!string.IsNullOrEmpty(ThumbnailUrl))
+                UrlValidation.Validate(ThumbnailUrl);
+            if (!string.IsNullOrEmpty(ImageUrl))
+                UrlValidation.Validate(ImageUrl);
             if (Author != null)
             {
-                if(!string.IsNullOrEmpty(Author.Url) && !Uri.IsWellFormedUriString(Author.Url, UriKind.Absolute))
-                    throw new InvalidOperationException("Author Url must be well formatted and include its protocol (either HTTP or HTTPS)");
-                if (!string.IsNullOrEmpty(Author.IconUrl) && !Uri.IsWellFormedUriString(Author.IconUrl, UriKind.Absolute))
-                    throw new InvalidOperationException("Author Icon Url must be well formatted and include its protocol (either HTTP or HTTPS)");
+                if (!string.IsNullOrEmpty(Author.Url))
+                    UrlValidation.Validate(Author.Url);
+                if (!string.IsNullOrEmpty(Author.IconUrl))
+                    UrlValidation.Validate(Author.IconUrl);
+            }
+            if(Footer != null)
+            {
+                if (!string.IsNullOrEmpty(Footer.IconUrl))
+                    UrlValidation.Validate(Footer.IconUrl);
             }
-
             var fields = ImmutableArray.CreateBuilder<EmbedField>(Fields.Count);
             for (int i = 0; i < Fields.Count; i++)
                 fields.Add(Fields[i].Build());

src/Discord.Net.Core/Utils/UrlValidation.cs

@@ -0,0 +1,22 @@
+using System;
+
+namespace Discord.Utils
+{
+    static class UrlValidation
+    {
+        /// <summary>
+        /// Not full URL validation right now. Just ensures protocol is present and that it's either http or https
+        /// </summary>
+        /// <param name="url">url to validate before sending to Discord</param>
+        /// <exception cref="InvalidOperationException">A URL must include a protocol (http or https).</exception>
+        /// <returns>true if url is valid by our standard, false if null, throws an error upon invalid </returns>
+        public static bool Validate(string url)
+        {
+            if (string.IsNullOrEmpty(url))
+                return false;
+            if(!(url.StartsWith("http://", StringComparison.OrdinalIgnoreCase) || (url.StartsWith("https://", StringComparison.OrdinalIgnoreCase))))
+                throw new InvalidOperationException($"Url {url} must be include its protocol (either HTTP or HTTPS)");
+            return true;
+        }
+    }
+}