Accessor: cameras/Foscam

An accessor for a Foscam camera. The commands that this accessor supports are:

1. snapshot: Take a picture and produce it on the '''response''' output.
2. videostream: Output a video stream.
3. center: Center the camera. This will pan to find the center.
4. down: Move the camera down.
5. left: Move the camera left.
6. right: Move the camera left.
7. up: Move the camera left. For the last four motion command commands, you can specify an argument 'degree' in the arguments object to move a specified number of degrees. If no degree argument is given, the camera will move as far as it can in the specified direction, or until you give it a stop command:
8. stop down
9. stop left
10. stop right
11. stop up The following commands start and stop continual panning of the camera:
12. horizontal patrol
13. vertical patrol
14. stop horizontal patrol
15. stop vertical patrol

If you select videostream then you can specify 'resolution' and 'rate' options. FIXME: Make more user friendly versions of these. resolution = 8 specifies 320*240. rate=15 specifies 1fps. NOTE: The videostream selection appears to not actually work. It has been known to produce a frame or two, but it needs further work.

The options input can be a string URL or an object with the following fields:

1. '''headers''': An object containing request headers. By default this is an empty object. Items may have a value that is an array of values, for headers with more than one value.
2. '''keepAlive''': A boolean that specified whether to keep sockets around in a pool to be used by other requests in the future. This defaults to false.
3. '''method''': A string specifying the HTTP request method. This defaults to 'GET', but can also be 'PUT', 'POST', 'DELETE', etc.
4. '''url''': A string that can be parsed as a URL, or an object containing the following fields:
   • '''host''': A string giving the domain name or IP address of the server to issue the request to. This defaults to 'localhost'.
   • '''protocol''': The protocol. This is a string that defaults to 'http'.
   • '''port''': Port of remote server. This defaults to 80.

This accessor has been tested with a Foscam NVision F18910W only. The (rather poor) documentation for the camera API can be found here: http://www.foscam.es/descarga/ipcam_cgi_sdk.pdf. The design of this accessor is inspired by the "foscam" module for Node.js, found at https://github.com/fvdm/nodejs-foscam.