"this.publish" function in js/samplesviewer.js can overwrite server files

[euanong]

When a user clicks the 'publish' button in the 'Planet' view there are no checks to see whether the project is already published - this slows the code down and also can overwrite entries already present on the server. Maybe a user could be forced to name their project with a name that has not already been used?

Identical issue to https://github.com/walterbender/musicblocks/issues/387

[tradzik]

The bug is even more serious. Anyone who knows the algorithm (API key, request schema are hard-coded) can possibly overwrite any file on the server (by-passing getPublishableName validation using external tools, like e.g. cURL).