From 617b65551062b38abffcbcde154285a51db64f91 Mon Sep 17 00:00:00 2001
From: Steve Sanderson <SteveSandersonMS@users.noreply.github.com>
Date: Tue, 24 Sep 2019 22:30:31 +0100
Subject: [PATCH] Add ReadAllAsync

---
 BlazorInputFile/BlazorInputFile.csproj     |  2 +-
 BlazorInputFile/FileListEntryExtensions.cs | 38 ++++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 BlazorInputFile/FileListEntryExtensions.cs

diff --git a/BlazorInputFile/BlazorInputFile.csproj b/BlazorInputFile/BlazorInputFile.csproj
index d9551e7..f449646 100644
--- a/BlazorInputFile/BlazorInputFile.csproj
+++ b/BlazorInputFile/BlazorInputFile.csproj
@@ -4,7 +4,7 @@
     <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
     <RazorLangVersion>3.0</RazorLangVersion>
     <LangVersion>preview</LangVersion>
-    <PackageVersion>0.1.0-preview</PackageVersion>
+    <PackageVersion>0.1.0-preview-00002</PackageVersion>
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
   </PropertyGroup>
 
diff --git a/BlazorInputFile/FileListEntryExtensions.cs b/BlazorInputFile/FileListEntryExtensions.cs
new file mode 100644
index 0000000..f2a4657
--- /dev/null
+++ b/BlazorInputFile/FileListEntryExtensions.cs
@@ -0,0 +1,38 @@
+using System;
+using System.IO;
+using System.Threading.Tasks;
+
+namespace BlazorInputFile
+{
+    public static class FileListEntryExtensions
+    {
+        /// <summary>
+        /// Reads the entire uploaded file into a <see cref="MemoryStream"/>. This will allocate
+        /// however much memory is needed to hold the entire file, or will throw if the client
+        /// tries to supply more than <paramref name="maxSizeBytes"/> bytes. Be careful not to
+        /// let clients allocate too much memory on the server.
+        /// </summary>
+        /// <param name="fileListEntry">The <see cref="IFileListEntry"/>.</param>
+        /// <param name="maxSizeBytes">The maximum amount of data to accept.</param>
+        public static async Task<MemoryStream> ReadAllAsync(this IFileListEntry fileListEntry, int maxSizeBytes = 1024*1024)
+        {
+            if (fileListEntry is null)
+            {
+                throw new ArgumentNullException(nameof(fileListEntry));
+            }
+
+            // We can trust .Length to be correct (and can't change later) because the implementation
+            // won't supply more bytes than this, even if the JS-side code would send more data.
+            var sourceData = fileListEntry.Data;
+            if (sourceData.Length > maxSizeBytes)
+            {
+                throw new ArgumentOutOfRangeException(nameof(fileListEntry), $"The maximum allowed size is {maxSizeBytes}, but the supplied file is of length {fileListEntry.Size}.");
+            }
+
+            var result = new MemoryStream();
+            await sourceData.CopyToAsync(result);
+            result.Seek(0, SeekOrigin.Begin);
+            return result;
+        }
+    }
+}