I'm looking into push notifications for an app I'm creating. I've heard lots about UrbanAirship but I can't seem to find a definitive reason why I should use it? As far as I understand it UA is a middle man? This page shows the free version doesn't have a push composer, so a developer will still need a server themselves to create the notification, if their own server is needed then I might as well go directly to APNS?
What is the point and advantage of UA? And if you use it how do you send notifications without your own server?
A working implementation of push notifications involves many things, such as:
Urban Airship takes care of 1-5 for you, which greatly simplifies the whole process. Yes, you if were just sending a message to one device, you could probably find a C# or python or Objective-C library to connect to Apple and form the message but as soon as you need to keep track of a large number of devices, Urban Airship provides a service for free (if under 1 million pushes a month) to take a lot of work off your shoulders.
(And this is just for the basic push service for iPhone, as this is the only service I have used)
To answer your other question, you do still need some 'server' or program to know when to push (#6). I, for example, monitor twitter with a python program for keywords and send out notifications when I see those. My program is not concerned with the details of how to send notifications, the Urban Airship library I use takes care of the interaction with Urban Airship and Apple.