How to Add an Attachment to a User Story using Ral

Question

We're in the process of porting our .NET Rally code from SOAP to the REST .NET API. So far so good, the REST API seems to be faster and is easier to use since there's no WSDL to break each time the work product custom fields change in the Rally Workspace.

I'm having trouble with one thing though as we try to replicate the ability to upload attachments. We're following a very similar procedure as to the one outlined in this posting:

Rally SOAP API - How do I add an attachment to a Hierarchical Requirement

Whereby the image is read into a System.Drawing.Image. We use the ImageToByteArray function to convert the image to a byte array which then gets assigned to the AttachmentContent, which is created first.

Then, the Attachment gets created, and wired up to both AttachmentContent, and the HierarchicalRequirement.

All of the creation events work great. The content object gets created fine. Then the new attachment called "Image.png" gets created and linked to the Story. But when I download the resulting attachment from Rally, Image.png has zero bytes! I've tried this with different images, JPEG's, PNG's, etc. all with the same results.

An excerpt of the code showing our process is included below. Is there something obvious that I'm missing? Thanks in advance.

    // .... Read content into a System.Drawing.Image called imageObject ....

    // Convert Image to byte array
    byte[] imageBytes = ImageToByteArray(imageObject, System.Drawing.Imaging.ImageFormat.Png);
    var imageLength = imageBytes.Length;

    // AttachmentContent
    DynamicJsonObject attachmentContent = new DynamicJsonObject();
    attachmentContent["Content"] = imageBytes ;

    CreateResult cr = restApi.Create("AttachmentContent", myAttachmentContent);
    String contentRef = cr.Reference;
    Console.WriteLine("Created: " + contentRef);

    // Set up attachment
    DynamicJsonObject newAttachment = new DynamicJsonObject();
    newAttachment["Artifact"] = story;
    newAttachment["Content"] = attachmentContent;
    newAttachment["Name"] = "Image.png";
    newAttachment["ContentType"] = "image/png";
    newAttachment["Size"] = imageLength;
    newAttachment["User"] = user;


    // Create the attachment in Rally
    cr = restApi.Create("Attachment", newAttachment);

    String attachRef = cr.Reference;
    Console.WriteLine("Created: " + attachRef);

}

public static byte[] ImageToByteArray(Image image, System.Drawing.Imaging.ImageFormat format)
{
    using (MemoryStream ms = new MemoryStream())
    {
        image.Save(ms, format);

        // Convert Image to byte[]                
        byte[] imageBytes = ms.ToArray();
        return imageBytes;
    }
}

Answer 1

This issue also had me puzzled for a while - finally sorted it out about a week ago.

Two observations:

1. While Rally's SOAP API will serialize the byte array into a Base64 string behind the scenes, REST doesn't do this step for you and will expect a Base64-formatted String to be passed as the Content attribute for the AttachmentContent object.
2. System.Drawing.Image.Length as shown in your example won't provide the correct length that Rally's WSAPI is expecting. You need to pass the length of the Base64-formatted string after being converted back to a regular String. This is also the same as the length of the byte array.

I'm including a code sample to illustrate:

// System Libraries
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing.Imaging;
using System.Drawing;
using System.IO;
using System.Web;

// Rally REST API Libraries
using Rally.RestApi;
using Rally.RestApi.Response;

namespace RestExample_CreateAttachment
{
    class Program
    {
        static void Main(string[] args)
        {
            // Set user parameters
            String userName = "[e-mail]";
            String userPassword = "password";

            // Set Rally parameters
            String rallyURL = "https://rally1.rallydev.com";
            String rallyWSAPIVersion = "1.36";

            //Initialize the REST API
            RallyRestApi restApi;
            restApi = new RallyRestApi(userName,
                                       userPassword,
                                       rallyURL,
                                       rallyWSAPIVersion);

            // Create Request for User
            Request userRequest = new Request("user");
            userRequest.Fetch = new List<string>()
                {
                    "UserName",
                    "Subscription",
                    "DisplayName",
                };

            // Add a Query to the Request
            userRequest.Query = new Query("UserName",Query.Operator.Equals,userName);

            // Query Rally
            QueryResult queryUserResults = restApi.Query(userRequest);

            // Grab resulting User object and Ref
            DynamicJsonObject myUser = new DynamicJsonObject();
            myUser = queryUserResults.Results.First();
            String myUserRef = myUser["_ref"];

            //Set our Workspace and Project scopings
            String workspaceRef = "/workspace/12345678910";
            String projectRef = "/project/12345678911";
            bool projectScopingUp = false;
            bool projectScopingDown = true;

            // Find User Story that we want to add attachment to

            // Tee up Story Request
            Request storyRequest = new Request("hierarchicalrequirement");
            storyRequest.Workspace = workspaceRef;
            storyRequest.Project = projectRef;
            storyRequest.ProjectScopeDown = projectScopingDown;
            storyRequest.ProjectScopeUp = projectScopingUp;

            // Fields to Fetch
            storyRequest.Fetch = new List<string>()
                {
                    "Name",
                    "FormattedID"
                };

            // Add a query
            storyRequest.Query = new Query("FormattedID", Query.Operator.Equals, "US43");

            // Query Rally for the Story
            QueryResult queryResult = restApi.Query(storyRequest);

            // Pull reference off of Story fetch
            var storyObject = queryResult.Results.First();
            String storyReference = storyObject["_ref"];

            // Read In Image Content
            String imageFilePath = "C:\\Users\\username\\";
            String imageFileName = "image1.png";
            String fullImageFile = imageFilePath + imageFileName;
            Image myImage = Image.FromFile(fullImageFile);

            // Get length from Image.Length attribute - don't use this in REST though
            // REST expects the length of the image in number of bytes as converted to a byte array
            var imageFileLength = new FileInfo(fullImageFile).Length;
            Console.WriteLine("Image File Length from System.Drawing.Image: " + imageFileLength);

            // Convert Image to Base64 format
            string imageBase64String = ImageToBase64(myImage, System.Drawing.Imaging.ImageFormat.Png);           

            // Length calculated from Base64String converted back
            var imageNumberBytes = Convert.FromBase64String(imageBase64String).Length;

            // This differs from just the Length of the Base 64 String!
            Console.WriteLine("Image File Length from Convert.FromBase64String: " + imageNumberBytes);

            // DynamicJSONObject for AttachmentContent
            DynamicJsonObject myAttachmentContent = new DynamicJsonObject();
            myAttachmentContent["Content"] = imageBase64String;

            try
            {
                CreateResult myAttachmentContentCreateResult = restApi.Create("AttachmentContent", myAttachmentContent);
                String myAttachmentContentRef = myAttachmentContentCreateResult.Reference;
                Console.WriteLine("Created: " + myAttachmentContentRef);

                // DynamicJSONObject for Attachment Container
                DynamicJsonObject myAttachment = new DynamicJsonObject();
                myAttachment["Artifact"] = storyReference;
                myAttachment["Content"] = myAttachmentContentRef;
                myAttachment["Name"] = "AttachmentFromREST.png";
                myAttachment["Description"] = "Attachment Desc";
                myAttachment["ContentType"] = "image/png";
                myAttachment["Size"] = imageNumberBytes;
                myAttachment["User"] = myUserRef;

                CreateResult myAttachmentCreateResult = restApi.Create("Attachment", myAttachment);

                List<string> createErrors = myAttachmentContentCreateResult.Errors;
                for (int i = 0; i < createErrors.Count; i++)
                {
                    Console.WriteLine(createErrors[i]);
                }

                String myAttachmentRef = myAttachmentCreateResult.Reference;
                Console.WriteLine("Created: " + myAttachmentRef);

            }
            catch (Exception e)
            {
                Console.WriteLine("Unhandled exception occurred: " + e.StackTrace);
                Console.WriteLine(e.Message);
            }
        }

        // Converts image to Base 64 Encoded string
        public static string ImageToBase64(Image image, System.Drawing.Imaging.ImageFormat format)
        {
            using (MemoryStream ms = new MemoryStream())
            {
                image.Save(ms, format);
                // Convert Image to byte[]                
                byte[] imageBytes = ms.ToArray();

                // Convert byte[] to Base64 String
                string base64String = Convert.ToBase64String(imageBytes);

                return base64String;
            }
        }
    }
}