attachment apis and azure storage service

src/Api/Utilities/MultipartFormDataHelper.cs

@@ -0,0 +1,58 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.Features;
+using Microsoft.AspNetCore.WebUtilities;
+using Microsoft.Net.Http.Headers;
+using System;
+using System.IO;
+using System.Threading.Tasks;
+
+namespace Bit.Api.Utilities
+{
+    public static class MultipartFormDataHelper
+    {
+        private static readonly FormOptions _defaultFormOptions = new FormOptions();
+
+        public static async Task GetFilesAsync(this HttpRequest request, Func<Stream, string, Task> callback)
+        {
+            var boundary = GetBoundary(MediaTypeHeaderValue.Parse(request.ContentType),
+                _defaultFormOptions.MultipartBoundaryLengthLimit);
+            var reader = new MultipartReader(boundary, request.Body);
+
+            var section = await reader.ReadNextSectionAsync();
+            while(section != null)
+            {
+                ContentDispositionHeaderValue content;
+                if(ContentDispositionHeaderValue.TryParse(section.ContentDisposition, out content) &&
+                    HasFileContentDisposition(content))
+                {
+                    await callback(section.Body, HeaderUtilities.RemoveQuotes(content.FileName));
+                }
+
+                section = await reader.ReadNextSectionAsync();
+            }
+        }
+
+        private static string GetBoundary(MediaTypeHeaderValue contentType, int lengthLimit)
+        {
+            var boundary = HeaderUtilities.RemoveQuotes(contentType.Boundary);
+            if(string.IsNullOrWhiteSpace(boundary))
+            {
+                throw new InvalidDataException("Missing content-type boundary.");
+            }
+
+            if(boundary.Length > lengthLimit)
+            {
+                throw new InvalidDataException($"Multipart boundary length limit {lengthLimit} exceeded.");
+            }
+
+            return boundary;
+        }
+
+        private static bool HasFileContentDisposition(ContentDispositionHeaderValue content)
+        {
+            // Content-Disposition: form-data; name="myfile1"; filename="Misc 002.jpg"
+            return content != null && content.DispositionType.Equals("form-data") &&
+                (!string.IsNullOrEmpty(content.FileName) || !string.IsNullOrEmpty(content.FileNameStar));
+        }
+    }
+}