REST-full access: Cannot add file to repository in Gitlab

Question

I tried the following request:

curl -v -X POST --header "PRIVATE-TOKEN:myPrivateToken" 'url-of-gitlab/api/v3/projects/myProjectId/repository/files?file_path=1.json&branch_name=master&content=thefilecontent&commit_message=ACommitMessage'

However, I invariably get

"message":"You can only create files if you are on top of a branch"

in the response. I don't know what's missing from my request. The repository is newly created and I created it through the Gitlab UI. Maybe I need to create a branch first? Any help would do. Thank you very much.

Answer 1

The repository is newly created and I created it through the Gitlab UI.

A newly created repo (through GitLab or even a simple git init locally) has no branches (and no HEAD).
This is what I describe in "Why do I need to explicitly push a new branch?".

Maybe I need to create a branch first?

Yes, you do (at least a master branch)