Attachment uploaded to Azure devops through Rest api is not opening

Question

Hi i have followed Microsoft Doccument and uploaded Attachment devops and successfully attached it to work item. but when i dowloaded the file from devops userinteface file ish showing but not able to open it. here is code

converting Iformfile object to binary file Thanks in advace:)

 foreach (var item in enterddetals.Attachments)
            {
                TicketAttachemnts attachemnt = new TicketAttachemnts();
                attachemnt.TicketNo = enterddetals.TicketNo;
                attachemnt.Name = Path.GetFileName(item.FileName);
                attachemnt.FileType = Path.GetExtension(item.FileName);
                using (var target = new MemoryStream())
                {   
                    item.CopyTo(target);
                    attachemnt.FileContent = target.ToArray();
                }
                string attachjson = JsonConvert.SerializeObject(attachemnt);
                response = await _azuredevopsmnger.CreateAttachement("DevOps/CreateAttachement",attachjson);
              

Creating attachment and linking it to work item

  ResultClass res = new ResultClass();
                var personalaccesstoken = "";
                string baseUrl = "https://.../_apis/wit/attachments?fileName={0}&api-version=5.0";
                string baseUrl2 = "https:/.../_apis/wit/workitems/{0}?api-version=5.0";
                string url= string.Format(baseUrl, attachments.Name);
                string url2= string.Format(baseUrl2, attachments.TicketNo);
                string msg1 = "Ticket created successfully!! Your Ticket ID is :{0}";
                string msg2 = "Ohh....Ticket creation  Failed !! Reson: {0}";
            var json = new StringContent(JsonConvert.SerializeObject(attachments.FileContent), Encoding.UTF8, "application/json-patch+json");
                try
                {
                   
                    using (HttpClient client = new HttpClient())
                    {
                        client.DefaultRequestHeaders.Accept.Add(
                            new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));

                        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",
                            Convert.ToBase64String(
                                System.Text.ASCIIEncoding.ASCII.GetBytes(
                                    string.Format("{0}:{1}", "", personalaccesstoken))));

                        using (HttpResponseMessage response = client.PostAsync(url,json).Result)
                        {
                            response.EnsureSuccessStatusCode();
                            string responseBody = response.Content.ReadAsStringAsync().Result;
                            JObject data = JObject.Parse(responseBody);
                            string result = Convert.ToString(data["url"]);
                            List<Root> atc = new List<Root>();
                            Root att = new Root();
                            Attributes at = new Attributes();
                            Value v = new Value();
                            at.comment = "Spec for the work";
                            v.rel = "AttachedFile";
                            v.url = result;
                            v.attributes = at;
                            att.op = "add";
                            att.path = "/relations/-";
                            att.value = v;
                            atc.Add(att);
                            json = new StringContent(JsonConvert.SerializeObject(atc), Encoding.UTF8, "application/json-patch+json");
                           // return responseBody;
                        }
                        using (HttpResponseMessage response = client.PatchAsync(url2, json).Result)
                        {
                            response.EnsureSuccessStatusCode();
                            string responseBody = response.Content.ReadAsStringAsync().Result;
                            JObject data = JObject.Parse(responseBody);
                            int result = Convert.ToInt32(data["id"]);
                            res.IsSuccess = true;
                            res.ticketID = result;
                            res.message = string.Format(msg1, result);
                            return res;
                        }

[file stored in devops ][1]

[Error Msg when downloaded and opened it][1]

Answer 1

The problem comes from the json body you passed to the client.PostAsync method when you created a attachment.

You should read the files to bytes and build a ByteArrayContent instead of StringContent.

I donot know above item instance of yours. But when you create a attachment. Firstly, you need to read your files to bytes array. For example:

var bitArr = File.ReadAllBytes(@"C:\Test\UploadTemp\pic.png");

Then Convert to ByteArrayContent. Eg.

var json = new ByteArrayContent(bitArr);
HttpResponseMessage response = client.PostAsync(url, json).Result;

Please see below example:

public string uploadAttachment() {
            
            #read the files as byteArray           
            var bitArr = File.ReadAllBytes(@"C:\Test\UploadTemp\pic.png");
                       
            using (HttpClient client = new HttpClient())
            {
                client.DefaultRequestHeaders.Accept.Add(
                    new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));

                client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",
                    Convert.ToBase64String(
                        System.Text.ASCIIEncoding.ASCII.GetBytes(
                            string.Format("{0}:{1}", "", personalaccesstoken))));
                
                var json = new ByteArrayContent(bitArr); ##convert to ByteArrayContent

                json.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
                HttpResponseMessage response = client.PostAsync(url, json).Result;
                string responseBody = response.Content.ReadAsStringAsync().Result;
                JObject data = JObject.Parse(responseBody);
                string result = Convert.ToString(data["url"]);
                return result;

            }
}

I used above code to created attachments. And the attachments can be successfully opened when downloaded from UI.