MathewSachin/Captura · error · Exception

Not logged in to Imgur

Error message

Not logged in to Imgur

What it means

Thrown by ImgurUploader.GetAuthorizationHeader (src/Captura.Imgur/ImgurUploader.cs:73) when not anonymous and _settings.AccessToken is null/whitespace. The code only falls back to Client-ID when _settings.Anonymous is true; an authenticated profile without a stored access token cannot produce a Bearer header.

Source

Thrown at src/Captura.Imgur/ImgurUploader.cs:73

            }

            return new UploadResult
            {
                Url = uploadResponse.Data.Link,
                DeleteLink = $"https://api.imgur.com/3/image/{uploadResponse.Data.DeleteHash}"
            };
        }

        async Task<string> GetAuthorizationHeader()
        {
            if (_settings.Anonymous)
            {
                return $"Client-ID {_apiKeys.ImgurClientId}";
            }

            if (string.IsNullOrWhiteSpace(_settings.AccessToken))
            {
                throw new Exception("Not logged in to Imgur");
            }

            if (_settings.IsExpired())
            {
                if (!await RefreshToken())
                {
                    throw new Exception("Failed to Refresh Imgur token");
                }
            }

            return $"Bearer {_settings.AccessToken}";
        }

        async Task<bool> RefreshToken()
        {
            var args = new NameValueCollection
            {
                { "refresh_token", _settings.RefreshToken },

View on GitHub (pinned to 3fdf41529b)

Solutions

  1. Run the Imgur OAuth login flow to populate AccessToken before allowing non-anonymous uploads.
  2. Expose a UI guard: disable authenticated upload when AccessToken is empty and prompt to sign in.
  3. Fall back to anonymous mode (set _settings.Anonymous = true) if Client-ID keys are available.
  4. Persist AccessToken/RefreshToken/ExpiresAt immediately after login.

Example fix

// before
if (string.IsNullOrWhiteSpace(_settings.AccessToken))
    throw new Exception("Not logged in to Imgur");
// after
if (string.IsNullOrWhiteSpace(_settings.AccessToken))
    throw new ImgurAuthRequiredException(); // caller starts OAuth flow
Defensive patterns

Strategy: validation

Validate before calling

if (!_settings.Anonymous && string.IsNullOrWhiteSpace(_settings.AccessToken))
    throw new ImgurAuthRequiredException(); // caller runs OAuth

Type guard

static bool CanUploadAuthenticated(ImgurSettings s)
    => s.Anonymous || !string.IsNullOrWhiteSpace(s.AccessToken);

Try / catch

try { await uploader.Upload(img, fmt, progress); }
catch (Exception e) when (e.Message.Contains("Not logged in")) { await StartOAuthFlow(); }

Prevention

When it happens

Trigger: Calling Upload (or DeleteUploadedFile) in non-anonymous mode when ImgurSettings.AccessToken was never set, was cleared, or was never persisted after a prior OAuth flow.

Common situations: User toggled Imgur to authenticated mode but never completed the OAuth login; settings were reset/migrated and AccessToken came back empty; profile JSON partially corrupted.

Related errors

AI-assisted analysis of MathewSachin/Captura@3fdf41529b (2026-08-13). Data as JSON: /api/errors/41f2c4bb94f8275f. Report an issue: GitHub.