comm: More resilience against garbage on the line during connect

* leading and trailing null bytes will now be stripped
  * while connecting, a "wait" will also trigger switch to connected
    state - relevant when connecting without reset and initial "ok" for
    M110 gets mangled
  * extended virtual printer by new options to test the above:
      * mangled "ok" can now be injected via "preparedOks" setting and
        prepare_ok DEBUG command
      * simulated reset lines on beginning ("start" etc) now only sent
        if new setting "simulateReset" is true

Should fix #1770

src/octoprint/plugins/virtual_printer/virtual.py

@@ -25,6 +25,7 @@ class VirtualPrinter(object):
 	sleep_after_regex = re.compile("sleep_after ([GMTF]\d+) (\d+)")
 	sleep_after_next_regex = re.compile("sleep_after_next ([GMTF]\d+) (\d+)")
 	custom_action_regex = re.compile("action_custom ([a-zA-Z0-9_]+)(\s+.*)?")
+	prepare_ok_regex = re.compile("prepare_ok (.*)?")
 
 	def __init__(self, seriallog_handler=None, read_timeout=5.0, write_timeout=10.0):
 		import logging
@@ -50,8 +51,15 @@ class VirtualPrinter(object):
 		self.outgoing = queue.Queue()
 		self.buffered = queue.Queue(maxsize=settings().getInt(["devel", "virtualPrinter", "commandBuffer"]))
 
-		for item in ['start\n', 'Marlin: Virtual Marlin!\n', '\x80\n', 'SD card ok\n']:
-			self._send(item)
+		if settings().getBoolean(["devel", "virtualPrinter", "simulateReset"]):
+			for item in ['start\n', 'Marlin: Virtual Marlin!\n', '\x80\n', 'SD card ok\n']:
+				self._send(item)
+
+		self._prepared_oks = []
+		prepared = settings().get(["devel", "virtualPrinter", "preparedOks"])
+		if prepared and isinstance(prepared, list):
+			for prep in prepared:
+				self._prepared_oks.append(prep)
 
 		self.currentExtruder = 0
 		self.extruderCount = settings().getInt(["devel", "virtualPrinter", "numExtruders"])
@@ -385,7 +393,7 @@ class VirtualPrinter(object):
 	def _gcode_M114(self, data):
 		output = "X:{} Y:{} Z:{} E:{} Count: A:{} B:{} C:{}".format(self._lastX, self._lastY, self._lastZ, self._lastE, int(self._lastX*100), int(self._lastY*100), int(self._lastZ*100))
 		if not self._okBeforeCommandOutput:
-			output = "ok " + output
+			output = "{} {}".format(self._ok(), output)
 		self._send(output)
 		return True
 
@@ -498,7 +506,7 @@ class VirtualPrinter(object):
 
 			def request_resend():
 				self._send("Resend:%d" % expected)
-				self._send("ok")
+				self._send(self._ok())
 
 			if settings().getBoolean(["devel", "virtualPrinter", "repetierStyleResends"]):
 				request_resend()
@@ -538,6 +546,9 @@ class VirtualPrinter(object):
 			| Triggers a resend error with a checksum mismatch
 			drop_connection
 			| Drops the serial connection
+			prepare_ok <broken ok>
+			| Will cause <broken ok> to be enqueued for use,
+			| will be used instead of actual "ok"
 
 			# Reply Timing / Sleeping
 
@@ -546,7 +557,7 @@ class VirtualPrinter(object):
 			sleep_after <str:command> <int:seconds>
 			| Sleeps <seconds> s after each execution of <command>
 			sleep_after_next <str:command> <int:seconds>
-			| Sleeps <seconds> s after execution of <command>
+			| Sleeps <seconds> s after execution of next <command>
 			"""
 			for line in usage.split("\n"):
 				self._send("echo: {}".format(line.strip()))
@@ -575,6 +586,7 @@ class VirtualPrinter(object):
 				sleep_after_match = VirtualPrinter.sleep_after_regex.match(data)
 				sleep_after_next_match = VirtualPrinter.sleep_after_next_regex.match(data)
 				custom_action_match = VirtualPrinter.custom_action_regex.match(data)
+				prepare_ok_match = VirtualPrinter.prepare_ok_regex.match(data)
 
 				if sleep_match is not None:
 					interval = int(sleep_match.group(1))
@@ -595,6 +607,9 @@ class VirtualPrinter(object):
 					params = custom_action_match.group(2)
 					params = params.strip() if params is not None else ""
 					self._send("// action:{action} {params}".format(**locals()).strip())
+				elif prepare_ok_match is not None:
+					ok = prepare_ok_match.group(1)
+					self._prepared_oks.append(ok)
 			except:
 				pass
 
@@ -684,7 +699,7 @@ class VirtualPrinter(object):
 		output += " @:64\n"
 
 		if includeOk:
-			output = "ok " + output
+			output = "{} {}".format(self._ok(), output)
 		self._send(output)
 
 	def _parseHotendCommand(self, line, wait=False, support_r=False):
@@ -1060,9 +1075,9 @@ class VirtualPrinter(object):
 			return
 
 		if settings().getBoolean(["devel", "virtualPrinter", "okWithLinenumber"]):
-			self._send("ok %d" % self.lastN)
+			self._send("{} {}".format(self._ok(), self.lastN))
 		else:
-			self._send("ok")
+			self._send(self._ok())
 
 	def _sendWaitAfterTimeout(self, timeout=5):
 		time.sleep(timeout)
@@ -1073,6 +1088,12 @@ class VirtualPrinter(object):
 		if self.outgoing is not None:
 			self.outgoing.put(line)
 
+	def _ok(self):
+		ok = "ok"
+		if self._prepared_oks:
+			ok = self._prepared_oks.pop(0)
+		return ok
+
 class CharCountingQueue(queue.Queue):
 
 	def __init__(self, maxsize, name=None):

src/octoprint/settings.py

@@ -359,6 +359,8 @@ default_settings = {
 			"firmwareName": "Virtual Marlin 1.0",
 			"sharedNozzle": False,
 			"sendBusy": False,
+			"simulateReset": True,
+			"preparedOks": []
 		}
 	}
 }

src/octoprint/util/comm.py

@@ -1100,7 +1100,7 @@ class MachineCom(object):
 				def convert_line(line):
 					if line is None:
 						return None, None
-					stripped_line = line.strip()
+					stripped_line = line.strip().strip("\0")
 					return stripped_line, stripped_line.lower()
 
 				##~~ Error handling
@@ -1383,7 +1383,7 @@ class MachineCom(object):
 					if "start" in line and not startSeen:
 						startSeen = True
 						self.sayHello()
-					elif line.startswith("ok"):
+					elif line.startswith("ok") or (supportWait and line == "wait"):
 						self._onConnected()
 					elif time.time() > self._timeout:
 						self._log("There was a timeout while trying to connect to the printer")