1 files changed, 52 insertions, 0 deletions
diff --git a/src/SMAPI.Web/Framework/AllowLargePostsAttribute.cs b/src/SMAPI.Web/Framework/AllowLargePostsAttribute.cs
new file mode 100644
index 00000000..68ead3c2
--- /dev/null
+++ b/src/SMAPI.Web/Framework/AllowLargePostsAttribute.cs
@@ -0,0 +1,52 @@
+using System;
+using Microsoft.AspNetCore.Http.Features;
+using Microsoft.AspNetCore.Mvc.Filters;
+
+namespace StardewModdingAPI.Web.Framework
+{
+    /// <summary>A filter which increases the maximum request size for an endpoint.</summary>
+    /// <remarks>Derived from <a href="https://stackoverflow.com/a/38360093/262123"/>.</remarks>
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
+    public class AllowLargePostsAttribute : Attribute, IAuthorizationFilter, IOrderedFilter
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The underlying form options.</summary>
+        private readonly FormOptions FormOptions;
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The attribute order.</summary>
+        public int Order { get; set; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        public AllowLargePostsAttribute()
+        {
+            this.FormOptions = new FormOptions
+            {
+                ValueLengthLimit = 200 * 1024 * 1024 // 200MB
+            };
+        }
+
+        /// <summary>Called early in the filter pipeline to confirm request is authorized.</summary>
+        /// <param name="context">The authorisation filter context.</param>
+        public void OnAuthorization(AuthorizationFilterContext context)
+        {
+            IFeatureCollection features = context.HttpContext.Features;
+            IFormFeature formFeature = features.Get<IFormFeature>();
+
+            if (formFeature?.Form == null)
+            {
+                // Request form has not been read yet, so set the limits
+                features.Set<IFormFeature>(new FormFeature(context.HttpContext.Request, this.FormOptions));
+            }
+        }
+    }
+}