"helper functions"

from flask import abort

def find_one_or_404(collection, **kwargs):
      """Find a single document or raise a 404.

      This is like :meth:`~pymongo.collection.Collection.find_one`, but
      rather than returning ``None``, cause a 404 Not Found HTTP status
      on the request.

      .. code-block:: python

          usercollection = mydb['usercollection']
      
          @app.route("/user/<username>")
          def user_profile(username):
              userfound = find_one_or_404(usercollection, {"_id": username})
              return render_template("user.html",
                  user=userfound)
      """
      found = collection.find_one(**kwargs)
      if found is None:
          abort(404)
      return found