Add SaaS backend

This backend works just like the X11 backend, except it starts HamClock
on its own rather than relying on an existing instance. As the name
implies, it is intended for SaaS environments where multiple HamClocks
may be running on a single machine, and running unused instances would
be a significant waste of resources.

server/backends/saas.py

@@ -0,0 +1,38 @@
+import os
+import subprocess
+import threading
+import time
+
+
+def _long_touch(x, y):
+    os.environ['DISPLAY'] = config['display']
+    subprocess.run(['xdotool', 'mousemove', str(x), str(y), 'mousedown', '1'])
+    time.sleep(2)
+    subprocess.run(['xdotool', 'mouseup', '1'])
+
+
+def get_img():
+    os.environ['DISPLAY'] = config['display']
+    xwd = subprocess.Popen(['xwd', '-root', '-silent'], stdout=subprocess.PIPE)
+    convert = subprocess.Popen(['convert', 'xwd:-', 'bmp:img.bmp'], stdin=xwd.stdout)
+    convert.wait()
+    return 'img.bmp'
+
+
+def touch(x, y, is_long):
+    os.environ['DISPLAY'] = config['display']
+    if is_long:
+        threading.Thread(target=_long_touch, args=(x, y,)).start()
+    else:
+        subprocess.run(['xdotool', 'mousemove', str(x), str(y), 'click', '1'])
+
+
+def connect():
+    global _hamclock
+    os.environ['DISPLAY'] = config['display']
+    _hamclock = subprocess.Popen(config['hamclock_bin'])
+
+
+def disconnect():
+    _hamclock.terminate()
+    _hamclock.wait()