I'd like to modify a wiki page (Confluence by Atlassian - JIRA editors) programmatically (in python). What I tried so far is to simulate user behaviour:
This seems like the absolutely wrong way to go about it.
First off, Confluence has a plugin architecture which should allow you to manage content programmatically from the application itself without any kind of HTTP requests. Secondly, even if you don't want to, or can't, use the plugin API for some reason, the next obvious option is to use the SOAP/XML-RPC API.
There is no reason to actually mess with
textareas unless you're trying to do some kind of end-to-end test that includes testing GUI (e.g. automated cross-browser testing).