I recently created a small automated, remote (via web) controlled pet feeder using a Raspberry Pi single-board computer. The software is all in Python, and uses the simple HTTP server that is part of the Python libraries. I discovered Twisted about 2/3 of the way through the project, and now that I am done I would like to port it to use Twisted. After reading much of the documentation the Twisted web site, some aspects of this are fairly obvious to me, while others are not. I could use some advice on how best to design my app to fit in with the Twisted framework.
Here are the major components of the application: 1) A web site that hosts a combination of static content and some REST APIs. REST apis are called from Javascript Ajax, and do things like enable/disable the webcam, dispense a treat, etc. The static content consists of a single HTML page, some javascript scripts, and a JPG that is captured by #3 below. 2) A thread that runs a loop which manages the hardware. It does this with a simple state machine composed of a base class and subclasses for all the states that the hardware can be in (starting, idle, displaying status on the lcd, dispensing a treat, recovering from treat dispense cycle, shutting down). After initializing the hardware and the initial state, the thread loops continuously calling a "timeTick" event to the current state. WIthin the states, the code looks at various hardware status (like whether a button is pressed) and decides to take action or to trigger transition to another state. 3) A thread that runs continuously capturing images from a webcam. This thread captures low resolution images continuously, and compares sucessive frames to see if there is significant number of different pixels (motion detect). If so, it captures a higher resolution image, updates a symbolic link to point to the most recent image captured, and deletes any excessive files from previous captures. The images captured for the motion detect are handled by executing a process and capturing the stdout. The higher res images captured by executing a process that writes directly to a file. Porting #1 is very straightforward after going through the tutorial on Twisted web. However, I am not sure how to handle #2 and #3. I would appreciate some suggestions from those who are familiar with Twisted. Thanks
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