Add support for receiving multipart responses with attachments

src/SimpleSOAPClient/Exceptions/SoapAttachmentDeserializationException.cs

@@ -0,0 +1,20 @@
+using System;
+
+namespace SimpleSOAPClient.Exceptions
+{
+    /// <summary>
+    /// Thrown when a problem is encountered deserializing MTOM attachments.
+    /// </summary>
+    public class SoapAttachmentDeserializationException : SoapClientException
+    {
+        /// <inheritdoc />
+        public SoapAttachmentDeserializationException(string message) : base(message)
+        {
+        }
+
+        /// <inheritdoc />
+        public SoapAttachmentDeserializationException(string message, Exception innerException) : base(message, innerException)
+        {
+        }
+    }
+}

src/SimpleSOAPClient/Models/SoapEnvelope.cs

@@ -21,6 +21,10 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 #endregion
+
+using System.Collections.Generic;
+using System.Net.Http;
+
 namespace SimpleSOAPClient.Models
 {
     using System.Xml.Serialization;
@@ -42,6 +46,13 @@ public class SoapEnvelope
         /// </summary>
         [XmlElement("Body")]
         public SoapEnvelopeBody Body { get; set; }
+
+        /// <summary>
+        /// MTOM attachments of the SOAP message.
+        /// See https://www.w3.org/TR/soap12-mtom.
+        /// </summary>
+        [XmlIgnore]
+        public IDictionary<string, HttpContent> Attachments { get; set; }
 
         /// <summary>
         /// Initializes a new instance of <see cref="SoapEnvelope"/>

src/SimpleSOAPClient/Models/Xop/Include.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Xml.Serialization;
+
+namespace SimpleSOAPClient.Models.Xop
+{
+
+    /// <summary>
+    /// A reference to an attachment to the SoapEnvelope; see https://www.w3.org/TR/soap12-mtom/
+    /// </summary>
+    [XmlType(Namespace = Namespace)]
+    public class Include
+    {
+        /// <summary>
+        /// The W3 namespace for XOP Include
+        /// </summary>
+        public const string Namespace = "http://www.w3.org/2004/08/xop/include";
+
+        /// <summary>
+        /// The Content Id of the associated attachment.
+        /// </summary>
+        [XmlIgnore]
+        public string ContentId { get; set; }
+
+        /// <summary>
+        /// Helper method to generate the href attribute when serialized to XML.
+        /// </summary>
+        [XmlAttribute(AttributeName = "href")]
+        public string ContentIdAsHref
+        {
+            get => "cid:" + ContentId;
+            set
+            {
+                if (!value.StartsWith("cid:", StringComparison.OrdinalIgnoreCase))
+                {
+                    throw new ArgumentException("Content Id must start 'cid:'.");
+                }
+                ContentId = value.Substring(4, value.Length - 4);
+            }
+        }
+
+    }
+}

src/SimpleSOAPClient/SimpleSOAPClient.csproj

@@ -43,6 +43,7 @@
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net4.5'">
+    <PackageReference Include="Microsoft.AspNet.WebApi.Client" Version="5.2.6" />
     <Reference Include="System.Net.Http" />
   </ItemGroup>
 
@@ -51,8 +52,13 @@
   </ItemGroup>
 
   <ItemGroup Condition=" '$(TargetFramework)' == 'uap10.0' ">
+    <PackageReference Include="Microsoft.AspNet.WebApi.Client" Version="5.2.6" />
     <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="5.4.0" />
   </ItemGroup>
 
+  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
+    <PackageReference Include="Microsoft.AspNet.WebApi.Client" Version="5.2.6" />
+  </ItemGroup>
+
   <Import Project="$(MSBuildSDKExtrasTargets)" Condition="Exists('$(MSBuildSDKExtrasTargets)')" />
 </Project>

src/SimpleSOAPClient/SoapClient.cs

@@ -21,6 +21,9 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 #endregion
+
+using System.Text.RegularExpressions;
+
 namespace SimpleSOAPClient
 {
     using System;
@@ -33,12 +36,14 @@ namespace SimpleSOAPClient
     using Exceptions;
     using Handlers;
     using Models;
+
 
     /// <summary>
     /// The SOAP client that can be used to invoke SOAP Endpoints
     /// </summary>
     public class SoapClient : ISoapClient, IDisposable
     {
+        private readonly Regex _cidRegex = new Regex("^<(.*)>$");
         private readonly bool _disposeHttpClient = true;
         private readonly List<ISoapHandler> _handlers = new List<ISoapHandler>();
         private SoapClientSettings _settings;
@@ -198,12 +203,43 @@ await RunBeforeSoapEnvelopeSerializationHandlers(
                 await RunBeforeHttpRequestHandlers(
                     requestXml, url, action, trackingId,
                     beforeSoapEnvelopeSerializationHandlersResult.State, handlersOrderedAsc, ct);
-
+            
             var response =
                 await HttpClient.SendAsync(beforeHttpRequestHandlersResult.Request, ct).ConfigureAwait(false);
-
+
+            // Handle multipart responses
+            // DotNet Standard 1.1 isn't supported by the multipart library
+#if !NETSTANDARD1_1
+            IDictionary<string, HttpContent> attachments = new Dictionary<string, HttpContent>();
+            if (response.Content.IsMimeMultipartContent())
+            {
+                var multipart = await response.Content.ReadAsMultipartAsync(ct);
+                foreach (var content in multipart.Contents)
+                {
+                    if (content.Headers.ContentType.MediaType == "application/xop+xml")
+                    {
+                        // This part contains the Soap Envelop XML
+                        response.Content = content;
+                    }
+                    else
+                    {
+                        // Any other part is an attachment and should have a content id
+                        var cidMatch = _cidRegex.Match(content.Headers.GetValues("Content-Id").First());
+                        if (cidMatch.Success)
+                        {
+                            attachments.Add(cidMatch.Groups[1].Value, content);
+                        }
+                        else
+                        {
+                            throw new SoapAttachmentDeserializationException("Multipart message part without content id found; all attachments much have a content id.");
+                        }
+                    }
+                }
+            }
+#endif
+
             var handlersOrderedDesc = _handlers.OrderByDescending(e => e.Order).ToList();
-
+            
             var afterHttpResponseHandlersResult =
                 await RunAfterHttpResponseHandlers(
                     response, url, action, trackingId, beforeHttpRequestHandlersResult.State, handlersOrderedDesc, ct);
@@ -218,6 +254,9 @@ await RunAfterHttpResponseHandlers(
             {
                 responseEnvelope = 
                     Settings.SerializationProvider.ToSoapEnvelope(responseXml);
+#if !NETSTANDARD1_1
+                responseEnvelope.Attachments = attachments;
+#endif
             }
             catch (SoapEnvelopeDeserializationException)
             {

tests/SimpleSOAPClient.Tests/MultipartResponseTests.cs

@@ -0,0 +1,53 @@
+using System.Net;
+using System.Net.Http;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using SimpleSOAPClient.Models;
+using Xunit;
+
+namespace SimpleSOAPClient.Tests
+{
+    public class MultipartResponseTests
+    {
+        private const string AttachmentContents = "The Attachment Contents";
+        private const string AttachmentContentId = "test-content@test.com";
+
+        [Fact]
+        public async Task TestReceiveAndDeserializeSingleAttachment()
+        {
+            var httpMessageHandler = new TestHttpMessageHandler();
+            var httpClient = new HttpClient(httpMessageHandler);
+            var soapClient = new SoapClient(httpClient);
+
+            var result = await soapClient.SendAsync("http://test.com", "", SoapEnvelope.Prepare());
+            Assert.Equal(AttachmentContents, await result.Attachments[AttachmentContentId].ReadAsStringAsync());
+        }
+
+
+        private class TestHttpMessageHandler : HttpMessageHandler
+        {
+
+            protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+            {
+                var emptyEnvelope = new SoapEnvelopeSerializationProvider().ToXmlString(SoapEnvelope.Prepare());
+                var multipartResponse = new MultipartContent("related")
+                {
+                    new StringContent(emptyEnvelope, Encoding.UTF8, "application/xop+xml"),
+                    new StringContent(AttachmentContents, Encoding.UTF8, "text/plain")
+                    {
+                        Headers = {{"Content-Id", $"<{AttachmentContentId}>"}}
+                    }
+                };
+
+                return Task.FromResult(new HttpResponseMessage
+                {
+                    Version = HttpVersion.Version11,
+                    Content = multipartResponse,
+                    StatusCode = HttpStatusCode.OK,
+                    ReasonPhrase = "OK",
+                });
+            }
+        }
+    }
+}