Activity.generator is always {"objectType":"service", "displayName":"GNU Mediagoblin"}

Expected: {"objectType":"application", "displayName":"MyAppName"} when using an external client for posting.

Currently the "object" in the Activity.content is not translatable because it uses Activity.generate_content uses model.object_type which is purposefully forced to English as it's used in the API.

This could be fixed by doing:

{
    "image": _("an image"),
    "comment": _("a comment"),
    etc...
}

This would allow it be translatable and get the correct article in English which is currently missing.

While looking at ActivityIntermediator, I noticed some bits.

The .set method could probably be rewritten a bit:

# We need to flush so that self.id is populated
self.type = key
Session.flush()

# First set self as activity
obj.activity = self.id
Session.commit()

And instead of checking values in .save use a validator. See ​http://docs.sqlalchemy.org/en/latest/orm/mapper_config.html#simple-validators

@validates('type')
def validate_type(self, key, value):
    assert value in self.TYPES
    return value