MailAttachmentDownloader.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Xml;
using System.Xml.Linq;
using Microsoft.Exchange.WebServices.Data;
using System.Linq;
using System.Net;
using System.Security;
using System.Text;
using System.Threading.Tasks;

// EWS API setup: https://docs.microsoft.com/en-us/exchange/client-developer/exchange-web-services/get-started-with-ews-managed-api-client-applications
namespace HelloWorldEws
{
    class Program
    {
        //Office365
        private static string ewsUrl = "https://outlook.office365.com/EWS/Exchange.asmx";
        private static string accessToken = "eyJhbGciOiJSUzI1NiIsImtpZCI6IjA2MDBGOUY2NzQ2MjA3MzdFNzM0MDRFMjg3QzQ1QTgxOENCN0NFQjgiLCJ4NXQiOiJCZ0Q1OW5SaUJ6Zm5OQVRpaDhSYWdZeTN6cmciLCJ0eXAiOiJKV1QifQ.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.CdvjY8R7TGQH0RH4I7Z30DyngsybOR7PN2GJ-1X0SH69lbiR43f-pY9feDHS5_jPns99euc0eTmblACuwtPrSyjSxssqWY5biqBwCYFDfZsbDvHTfPFDT-OmfjcdODaN7NJ5LgIiGkPoufyobxJqLAVVzTx090MMQehdAU1mx5oo7VGtiOj5rvxg7kaRV2aBwlA-OxEbtRUOcu90pyf0a1gfvS4VjRPypfAQHIrw1yDweYyjMyxbMZL-UGcVq4tKFfCJ7wfu7yOC2SPAWPcLZionIyOQolQWJZPgxSMRZkDkhgtq8QLlGSPG8CYEyK9aGimvHVfZh-UbsNonlDsH4g";
        private static string attachmentId = "AAMkADBjYzYwMTIzLThjM2EtNDBhZS05ZGRhLTIwYjBmMjQyZGE5NABGAAAAAADsDqojOXLQQLy9kucrOsKxBwDKms47OMM6RKkDwbv8JKGNAAAAAAEMAADKms47OMM6RKkDwbv8JKGNAAAAAAmXAAABEgAQAESL5yeE1SlFqS5Vwv5mXyI=";
        private static string attachmentName = "0-neu-d3-303d630a16599a9a1070d21df143a36c.jpg";
        private static int fileSize = 90355;
        private static string contentType = "image/jpeg";

        //exchange         
        //private static string ewsUrl = "https://webmail.hostingcloudapp.com/EWS/Exchange.asmx"; //exchange
        //private static string accessToken = "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1dCI6ImthME5Hb19aNUkwRms1MXpKblZjT2tHbzFvbyJ9.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.lRHqs84WGnE3lB_nJnHr2X3lQNOsm5AJrJuHhX-VK4Z3yDsnzdDI6_LAl_21gRZoQpKR97M0xDxIqxUW9e9LrUoNOcxDZ5h1inN5S0yKG7A0xL1RlYAA3ko7ghxZjDGA94WdcD_tG4a3aoXiJtDFJtGAq59y89j-Lf9y23dK_DZFriEgB-yXEM9KVd6OlMsnhm0jIG3pYH_FOTy5e8m6Blywz37TxhaJlWm8jeH_JBHD4hDPlqd42d9EX2l7JM_UdSOJuee0iNja85m4-5lIePLqeRyZ38M1ikr8d1Q54Z_uvbPgrUYeu5P-pMcvmvJcuogqAt0RXiADXImpYLOaBw";
        //private static string attachmentId = "AAMkADJmMGZmZTUwLTgzZTctNDk5Yy04ZjJmLTY4MzYxYTJiYmQxMQBGAAAAAAB2mVUPbImQT7LU+UPpI76lBwDhiIwiE1kPSo1g2HdccRo4AAAAAAEMAADhiIwiE1kPSo1g2HdccRo4AAD28ChdAAABEgAQANPw47cwvjFChm/yoZEMAaM=";
        //private static string attachmentName = "package.json";
        //private static int fileSize = 4453;
        //private static string contentType = "application/json";

        static void Main(string[] args)
        {
            Console.WriteLine("Running program to download email attachments");

            AttachmentDetails at1 = new AttachmentDetails();
            at1.attachmentType = "0";
            at1.contentType = contentType;
            at1.id = attachmentId;
            at1.name = attachmentName;
            at1.isInline = false;
            at1.size = fileSize;

            AttachmentSampleServiceRequest attachmentSampleServiceRequest = new AttachmentSampleServiceRequest();
            attachmentSampleServiceRequest.attachmentToken = accessToken;
            attachmentSampleServiceRequest.ewsUrl = ewsUrl;
            attachmentSampleServiceRequest.service = "attachments service";
            attachmentSampleServiceRequest.attachments = new AttachmentDetails[1] { at1 };

            Program instance = new Program();
            AttachmentSampleServiceResponse resp = instance.GetAttachmentsFromExchangeServerUsingEWS(attachmentSampleServiceRequest);                                   
        }

       
        public class AttachmentSampleServiceRequest
        {
            public string attachmentToken { get; set; }
            public string ewsUrl { get; set; }
            public string service { get; set; }
            public AttachmentDetails[] attachments { get; set; }
        }

        public class AttachmentDetails
        {
            public string attachmentType { get; set; }
            public string contentType { get; set; }
            public string id { get; set; }
            public bool isInline { get; set; }
            public string name { get; set; }
            public int size { get; set; }
        }

        public class AttachmentSampleServiceResponse 
        {
            public Array attachmentNames { get; set; }
            public int attachmentsProcessed { get; set; }
        }


        private AttachmentSampleServiceResponse GetAttachmentsFromExchangeServerUsingEWS(AttachmentSampleServiceRequest request)
        {
            var attachmentsProcessedCount = 0;
            var attachmentNames = new List<string>();

            foreach (var attachment in request.attachments)
            {
                // Prepare a web request object.
                HttpWebRequest webRequest = WebRequest.CreateHttp(request.ewsUrl);
                webRequest.Headers.Add("Authorization",
                  string.Format("Bearer {0}", request.attachmentToken));
                webRequest.PreAuthenticate = true;
                webRequest.AllowAutoRedirect = false;
                webRequest.Method = "POST";
                webRequest.ContentType = "text/xml; charset=utf-8";

                // Construct the SOAP message for the GetAttachment operation.
                byte[] bodyBytes = Encoding.UTF8.GetBytes(
                  string.Format(GetAttachmentSoapRequest, attachment.id));
                webRequest.ContentLength = bodyBytes.Length;

                Stream requestStream = webRequest.GetRequestStream();
                requestStream.Write(bodyBytes, 0, bodyBytes.Length);
                requestStream.Close();

                // Make the request to the Exchange server and get the response.
                HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse();

                // If the response is okay, create an XML document from the reponse
                // and process the request.
                if (webResponse.StatusCode == HttpStatusCode.OK)
                {
                    var responseStream = webResponse.GetResponseStream();

                    var responseEnvelope = XElement.Load(responseStream);

                    // After creating a memory stream containing the contents of the
                    // attachment, this method writes the XML document to the trace output.
                    // Your service would perform it's processing here.
                    if (responseEnvelope != null)
                    {
                        var processResult = ProcessXmlResponse(responseEnvelope);
                        attachmentNames.Add(string.Format("{0} {1}", attachment.name, processResult));

                    }

                    // Close the response stream.
                    responseStream.Close();
                    webResponse.Close();

                }
                // If the response is not OK, return an error message for the
                // attachment.
                else
                {
                    var errorString = string.Format("Attachment \"{0}\" could not be processed. " +
                      "Error message: {1}.", attachment.name, webResponse.StatusDescription);
                    attachmentNames.Add(errorString);
                }
                attachmentsProcessedCount++;
            }

            // Return the names and number of attachments processed for display
            // in the add-in UI.
            var response = new AttachmentSampleServiceResponse();
            response.attachmentNames = attachmentNames.ToArray();
            response.attachmentsProcessed = attachmentsProcessedCount;

            return response;
        }


        // This method processes the response from the Exchange server.
        // In your application the bulk of the processing occurs here.
        private string ProcessXmlResponse(XElement responseEnvelope)
        {
            //Refer: https://github.com/Nymann74/ewpdemoapp/blob/a71ef41d2cd42e2c17b8ace2ac5b21d08bae2722/EWPDemoApp/Program.cs#L287
            // First, check the response for web service errors.
            IEnumerable<XElement> errorCodes = from errorCode in responseEnvelope.Descendants
                              ("{http://schemas.microsoft.com/exchange/services/2006/messages}ResponseCode")
                             select errorCode;
            // Return the first error code found.
            foreach (var errorCode in errorCodes)
            {
                if (errorCode.Value != "NoError")
                {
                    return string.Format("Could not process result. Error: {0}", errorCode.Value);
                }
            }

            // No errors found, proceed with processing the content.
            // First, get and process file attachments.
            var fileAttachments = from fileAttachment in responseEnvelope.Descendants
                              ("{http://schemas.microsoft.com/exchange/services/2006/types}FileAttachment")
                                  select fileAttachment;
            foreach (var fileAttachment in fileAttachments)
            {
                var fileContent = fileAttachment.Element("{http://schemas.microsoft.com/exchange/services/2006/types}Content");
                var fileData = System.Convert.FromBase64String(fileContent.Value);
                //var s = new MemoryStream(fileData);
                // Process the file attachment here.

                File.WriteAllBytes(attachmentName, fileData);
            }

            // Second, get and process item attachments.
            var itemAttachments = from itemAttachment in responseEnvelope.Descendants
                                  ("{http://schemas.microsoft.com/exchange/services/2006/types}ItemAttachment")
                                  select itemAttachment;
            foreach (var itemAttachment in itemAttachments)
            {
                var message = itemAttachment.Element("{http://schemas.microsoft.com/exchange/services/2006/types}Message");
                if (message != null)
                {
                    // Process a message here.
                    break;
                }
                var calendarItem = itemAttachment.Element("{http://schemas.microsoft.com/exchange/services/2006/types}CalendarItem");
                if (calendarItem != null)
                {
                    // Process calendar item here.
                    break;
                }
                var contact = itemAttachment.Element("{http://schemas.microsoft.com/exchange/services/2006/types}Contact");
                if (contact != null)
                {
                    // Process contact here.
                    break;
                }
                var task = itemAttachment.Element("{http://schemas.microsoft.com/exchange/services/2006/types}Tontact");
                if (task != null)
                {
                    // Process task here.
                    break;
                }
                var meetingMessage = itemAttachment.Element("{http://schemas.microsoft.com/exchange/services/2006/types}MeetingMessage");
                if (meetingMessage != null)
                {
                    // Process meeting message here.
                    break;
                }
                var meetingRequest = itemAttachment.Element("{http://schemas.microsoft.com/exchange/services/2006/types}MeetingRequest");
                if (meetingRequest != null)
                {
                    // Process meeting request here.
                    break;
                }
                var meetingResponse = itemAttachment.Element("{http://schemas.microsoft.com/exchange/services/2006/types}MeetingResponse");
                if (meetingResponse != null)
                {
                    // Process meeting response here.
                    break;
                }
                var meetingCancellation = itemAttachment.Element("{http://schemas.microsoft.com/exchange/services/2006/types}MeetingCancellation");
                if (meetingCancellation != null)
                {
                    // Process meeting cancellation here.
                    break;
                }
            }

            return string.Empty;
        }

        private const string GetAttachmentSoapRequest =
@"<?xml version=""1.0"" encoding=""utf-8""?>
<soap:Envelope xmlns:xsi=""https://www.w3.org/2001/XMLSchema-instance""
xmlns:xsd=""https://www.w3.org/2001/XMLSchema""
xmlns:soap=""http://schemas.xmlsoap.org/soap/envelope/""
xmlns:t=""http://schemas.microsoft.com/exchange/services/2006/types"">
<soap:Header>
<t:RequestServerVersion Version=""Exchange2013"" />
</soap:Header>
  <soap:Body>
    <GetAttachment xmlns=""http://schemas.microsoft.com/exchange/services/2006/messages""
    xmlns:t=""http://schemas.microsoft.com/exchange/services/2006/types"">
      <AttachmentShape/>
      <AttachmentIds>
        <t:AttachmentId Id=""{0}""/>
      </AttachmentIds>
    </GetAttachment>
  </soap:Body>
</soap:Envelope>";


    }
}