Reading images (attachments) via API not working using C#

Confluence Development Confluence Cloud
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1

Hi

I am able to successfully use the Confluence API to read the contents of a page. For a page that has an embedded image, I understand that it is saved in Confluence as an attachment and I’m able to get the URL of the attachment.

My code below, assuming json.results contains all the attachments for a page

                foreach (var attachment in json.results)
                {
                    string imageUrl = "https://coname.atlassian.net/wiki" + attachment._links.download;
                    string saveLocation = @"D:\" + attachment.title;

                    byte[] imageBytes;
                    HttpWebRequest imageRequest = (HttpWebRequest)WebRequest.Create(imageUrl);
                    WebResponse imageResponse = imageRequest.GetResponse();
                    Stream responseStream = imageResponse.GetResponseStream();
                    using (BinaryReader br = new BinaryReader(responseStream))
                    {
                        imageBytes = br.ReadBytes(500000);
                        br.Close();
                    }
                    responseStream.Close();
                    imageResponse.Close();

                    File.WriteAllBytes(saveLocation, imageBytes);
                }

The method to read the results to a byte array I found via a Google search, I write a jpg or png file, but trying to open it gives the error below

Screenshot_8

Could someone suggest how to resolve this or a better way of doing it?

Thanks

2

As an update, I think the issue is that I’m not authenticating to Confluence, so it’s returning something, but not the attachment.

How do I pass in authentication information?

3

@warren.levy, How are you authenticating for the normal REST API calls?

4

Hi @ibuchanan

I am using a stand-alone C# desktop application, so whilst running Jira and Confluence API calls, I use Basic authentication with 64 bit encoded email address / API token - this has worked successfully for ages.

I’m unsure how to authenticate when getting the attachments because it isn’t an API call.

Any help greatly appreciated.

5

I’ve finally managed to sort this

6

@warren.levy, please share!

7

The code I showed above is not the same as what I use to read the contents of a Confluence page, but I discovered that using the same code works if I read the output directly into a byte array, as opposed to a string, so the code looks like this

HttpWebRequest newRequest = WebRequest.Create(m_BaseUrl) as HttpWebRequest;
newRequest.ContentType = "application/json";
newRequest.Method = "GET";
newRequest.Proxy.Credentials = CredentialCache.DefaultCredentials;

string base64Credentials = GetEncodedCredentials();
newRequest.Headers.Add("Authorization", "Basic " + base64Credentials);

HttpWebResponse response = newRequest.GetResponse() as HttpWebResponse;

byte[] image;
Stream responseStream = response.GetResponseStream();
using (BinaryReader br = new BinaryReader(responseStream))
{
       image = br.ReadBytes(500000);
       br.Close();
}

The byte array image then has valid image data which can be written to a file

1 Like
8

I’m glad you got it working with API tokens and basic auth. If you do need to switch to OAuth, you now (like right now) have this option: