Incorrect workaround for #29526

Camunda 8 Topics
1

We created a simple diagram using a Camunda Form that allows users to upload a file via the File Picker. Initially, we expected that once a file was uploaded, it would automatically be added to the Document Store and made available as a process variable. However, we discovered that only the file’s metadata is created—no actual file is associated with it, and it cannot be accessed via the REST API.

Upon further investigation, we found that this is a known issue (#29526). We also tested the suggested workaround, but it had no effect. The only reliable way to make file upload and retrieval work is by using the Camunda 8 REST API (documentation), rather than relying on the Tasklist or Tasklist API as currently recommended.

2

Thank you for sharing your findings about issue #29526 and the file upload problems with Camunda Forms!

Classification: Problem

You’re absolutely right about the current state of this issue. Let me break down what we know:

Current Issue Status

Issue #29526 in Camunda 8.7.0 states that files are not uploaded to the document storage when starting a process with a start form from Web Modeler or Play mode.

Documented Workaround vs. Reality

The official workaround suggests:

  • Start the process from Tasklist or the Tasklist REST API instead of Web Modeler
  • This should allow the file picker to correctly upload files to the document store

However, as you’ve discovered, this workaround appears to be ineffective in practice.

Your Working Solution

You’ve found that using the Camunda 8 REST API /documents endpoint directly is the only reliable method. This approach:

  1. Uses a multipart/form-data request to upload files
  2. Returns document metadata including a documentId
  3. Allows proper file retrieval via the REST API

Next Steps

Since the documented workaround isn’t working for you, I’d recommend:

  1. Report this finding - Your experience suggests the workaround may be incomplete or there’s an additional issue. Please consider filing a new issue at https://github.com/camunda/camunda/issues with:

    • Your Camunda version (exact major.minor.patch)
    • Environment details (SaaS or Self-Managed)
    • Steps showing the workaround failure
    • Evidence that the REST API approach works

  2. Continue using the REST API approach - This appears to be the most reliable solution currently

  3. Monitor for updates - Keep an eye on future releases as this may be addressed in upcoming patches

Would you be able to share more details about your environment and the specific steps you tried with the Tasklist workaround? This information could help identify why the documented solution isn’t working and potentially help other users facing the same issue.

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