I'm trying to add An attachment to an Issue with Rest Api using C# but it returns

[helpdesk]

Code: 

public static void SendFileToServer(string issueKey)
{
FileInfo fi = new FileInfo(@"H:\74715-Screen_Custodian Documents Tracking.xlsx");
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
byte[] fileContents = File.ReadAllBytes(fi.FullName);

//https://your-domain.atlassian.net/rest/api/2/issue/XYZ-315/attachments

string urlPath = "https://instance.atlassian.net/rest/api/2/issue/" + issueKey + "/attachments";
//Uri webService = new Uri(string.Format("{0}/{1}/attachments", urlPath, IssueKey));

HttpRequestMessage requestMessage = new HttpRequestMessage(HttpMethod.Post, urlPath);
requestMessage.Headers.ExpectContinue = false;

MultipartFormDataContent multiPartContent = new MultipartFormDataContent("----MyGreatBoundary");
ByteArrayContent byteArrayContent = new ByteArrayContent(fileContents);
byteArrayContent.Headers.Add("Content-Type", "image/png");
byteArrayContent.Headers.Add("X-Atlassian-Token", "no-check");
multiPartContent.Add(byteArrayContent, "file", fi.Name);
requestMessage.Content = multiPartContent;

HttpClient httpClient = new HttpClient();
httpClient.DefaultRequestHeaders.Add("Authorization", "Basic " + Convert.ToBase64String(Encoding.Default.GetBytes("email@mail.com" + ":" + "token_key")));
httpClient.DefaultRequestHeaders.Add("X-Atlassian-Token", "no-check");
try
{
Task<HttpResponseMessage> httpRequest = httpClient.SendAsync(requestMessage, HttpCompletionOption.ResponseContentRead, CancellationToken.None);
HttpResponseMessage httpResponse = httpRequest.Result;
HttpStatusCode statusCode = httpResponse.StatusCode;
HttpContent responseContent = httpResponse.Content;

if (responseContent != null)
{
Task<String> stringContentsTask = responseContent.ReadAsStringAsync();
String stringContents = stringContentsTask.Result;
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}

Response: 

StatusCode: 404, ReasonPhrase: 'Not Found', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
Timing-Allow-Origin: *
X-Arequestid: 4fd8a5843528593fd5f6f4675ebc0fe9
X-Seraph-Loginreason: AUTHENTICATED_FAILED
X-Content-Type-Options: nosniff
X-Xss-Protection: 1; mode=block
Atl-Traceid: 991dd907e1623a5c
Report-To: {"endpoints": [{"url": "https://dz8aopenkvv6s.cloudfront.net"}], "group": "endpoint-1", "include_subdomains": true, "max_age": 600}
Nel: {"failure_fraction": 0.001, "include_subdomains": true, "max_age": 600, "report_to": "endpoint-1"}
Strict-Transport-Security: max-age=63072000; includeSubDomains; preload
Transfer-Encoding: chunked
Cache-Control: no-store, no-transform, no-cache
Date: Tue, 18 Jul 2023 18:58:51 GMT
Set-Cookie: atlassian.xsrf.token=B659-IW08-H939-Y50O_58c27279e8f737f89f2c485a7701855499fe5be8_lout; path=/; SameSite=None; Secure
Server: AtlassianEdge
Content-Type: application/json; charset=UTF-8
}}

[Hyrum Steffensen {Appfire}]

Hello helpdesk,

I believe you need to add an attachment id to use the /attachments endpoint. For example:

string urlPath = "https://instance.atlassian.net/rest/api/2/issue/" + issueKey + "/attachments/10000";

See the Atlassian documentation on REST API for using the /attachments endpoint.

If you are interested in how I got this result, see my troubleshooting steps below.

Trying Out the /issue Endpoint

I see that the error message posted is "401 - Not Found". This usually means that the URL is malformed. I tried out the URL in a browser and get a similar error message. Here is the URL I used:

<BASE_URL>/rest/api/2/issue/DEMO-1/attachments

I then tried out the URL without "attachments" at the end and see data.

<BASE_URL>/rest/api/2/issue/DEMO-1

When I search for "attachment" in the JSON returned, I see something like the following (I have removed some of the data for readability).

"attachment": [ { "self": "<BASE_URL>/rest/api/2/attachment/10000", "id": "10000", "filename": "attachment name 1" }, { "self": "<BASE_URL>/rest/api/2/attachment/10002", "id": "10002", "filename": "attachment name 2" } ] 

In the results, the "self" value from the JSON seems like a good thing to try, so I tried the following in the web browser and it worked.

<BASE_URL>/rest/api/2/attachment/10000

Suggested Troubleshooting Steps:

• Try out any Jira REST API in the web browser before trying it out in code.
• Try the same REST API using GET (this tends to be less complicated for troubleshooting).
• Check authentication values in the code.
• When possible, post REST code as curl because more Community users can read and understand curl.
• Consider troubleshooting REST endpoints using Postman. Postman has a nice code export feature you can use to export code as C#, curl or other languages. You can also import curl code.

Please let us know how it goes!

Hyrum