electron simulator (#531)

1 files changed, 110 insertions, 0 deletions

diff --git a/lib/api/server.py b/lib/api/server.py
new file mode 100644
index 00000000..c57a1785
--- /dev/null
+++ b/lib/api/server.py
@@ -0,0 +1,110 @@
+import errno
+import logging
+import socket
+from threading import Thread
+import time
+
+from flask import Flask, request, g
+import requests
+
+from ..utils.json import InkStitchJSONEncoder
+from .simulator import simulator
+from .stitch_plan import stitch_plan
+
+
+class APIServer(Thread):
+    def __init__(self, *args, **kwargs):
+        self.extension = args[0]
+        Thread.__init__(self, *args[1:], **kwargs)
+        self.daemon = True
+        self.shutting_down = False
+        self.app = None
+        self.host = None
+        self.port = None
+        self.ready = False
+
+        self.__setup_app()
+
+    def __setup_app(self):  # noqa: C901
+        self.app = Flask(__name__)
+        self.app.json_encoder = InkStitchJSONEncoder
+
+        self.app.register_blueprint(simulator, url_prefix="/simulator")
+        self.app.register_blueprint(stitch_plan, url_prefix="/stitch_plan")
+
+        @self.app.before_request
+        def store_extension():
+            # make the InkstitchExtension object available to the view handling
+            # this request
+            g.extension = self.extension
+
+        @self.app.route('/shutdown', methods=['POST'])
+        def shutdown():
+            self.shutting_down = True
+            request.environ.get('werkzeug.server.shutdown')()
+            return "shutting down"
+
+        @self.app.route('/ping')
+        def ping():
+            return "pong"
+
+    def stop(self):
+        # for whatever reason, shutting down only seems possible in
+        # the context of a flask request, so we'll just make one
+        requests.post("http://%s:%s/shutdown" % (self.host, self.port))
+
+    def disable_logging(self):
+        logging.getLogger('werkzeug').setLevel(logging.ERROR)
+
+    def run(self):
+        self.disable_logging()
+
+        self.host = "127.0.0.1"
+        self.port = 5000
+
+        while True:
+            try:
+                self.app.run(self.host, self.port, threaded=True)
+            except socket.error as e:
+                if e.errno == errno.EADDRINUSE:
+                    self.port += 1
+                    continue
+                else:
+                    raise
+            else:
+                break
+
+    def ready_checker(self):
+        """Wait until the server is started.
+
+        Annoyingly, there's no way to get a callback to be run when the Flask
+        server starts.  Instead, we'll have to poll.
+        """
+
+        while True:
+            if self.port:
+                try:
+                    response = requests.get("http://%s:%s/ping" % (self.host, self.port))
+                    if response.status_code == 200:
+                        break
+                except socket.error, e:
+                    if e.errno == errno.ECONNREFUSED:
+                        pass
+                    else:
+                        raise
+
+            time.sleep(0.1)
+
+    def start_server(self):
+        """Start the API server.
+
+        returns: port (int) -- the port that the server is listening on
+                   (on localhost)
+        """
+
+        checker = Thread(target=self.ready_checker)
+        checker.start()
+        self.start()
+        checker.join()
+
+        return self.port