Blender on webserver. How to realize my workflow?

I need to realize following workflow:

  1. User via html page upload his model to webserver (i.e. obj) to folder “input” via php.
  2. Blender on webserver imports obj, and exports to dae to folder “output”.

I know that Blender can be controlled via python scripts, but i’m totally not understand how to realize it.

i.e.

  1. i must download Blender 2.79 version from site (which version, for Linux?)
  2. i must upload folder with blender to webserver (server with which capabilities? )
  3. i must write script myscript.py, and put it in blender folder (what is the contents of this script)
  4. i must upload file via php, and trigger myscript.py (how to run this script)