Extend File.write() to optionally write files to specific folders

[phorward]

In a customer project (viur-core 3.5), I've written this function some time ago. It writes a file to the File module, but also to a specific location. This can be seen as an extension for File.write(), so that it should be generalized and integrated into viur-core.

class File(_File):

	def write_to_folder(self, foldername, filename, content, mimetype="text/plain"):
		"""
		Write a file into the file module to a specified folder.
		The foldername is both the folder's initial name and name stored as the key.
		The folder can be renamed later on by the user, but the key remains.
		The folder is created under the module root node.
		"""
		# Check for foldername
		rootnode = self.ensureOwnModuleRootNode()

		folderskel = self.baseSkel("node")
		folderkey = db.Key(folderskel.kindName, foldername)

		# Create the folder if it doesn't exist
		if not folderskel.fromDB(folderkey):
			folderskel["key"] = folderkey
			folderskel["name"] = foldername
			folderskel["parentrepo"] = folderskel["parententry"] = rootnode.key
			folderskel.toDB()

		# Save the file into the folder.
		dl_key = utils.generateRandomString()

		blob = bucket.blob("%s/source/%s" % (dl_key, filename))
		blob.upload_from_file(io.BytesIO(content), content_type=mimetype)

		skel = self.addSkel("leaf")

		skel["name"] = filename
		skel["size"] = blob.size
		skel["mimetype"] = mimetype
		skel["dlkey"] = dl_key
		skel["parentrepo"] = rootnode.key
		skel["parententry"] = folderkey
		skel["pending"] = False
		skel["weak"] = False
		skel["width"] = 0
		skel["height"] = 0

		assert skel.toDB()
		return skel

[phorward]

Some further ideas on this issue:

• it should be an extension to File.write()
• it should accept for a root-node, and default to self.ensureOwnModuleRootNode()
• it should also accept a path of folders as an iterable of str, so ("this", "is", "a", "valid path"). The folders should be created when not existing.