Refactoring node code into nodeclient module #2
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,146 @@ | ||
| import json | ||
| import os | ||
| import subprocess | ||
| import threading | ||
| import time | ||
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||
| # queue module name changed from Python 2 to 3 | ||
| try: | ||
| import Queue as queue | ||
| except ImportError: | ||
| import queue | ||
|
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| class NodeClient: | ||
| __HEADER_CONTENT_LENGTH = b"Content-Length: " | ||
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| def __init__(self, scriptPath): | ||
| """ | ||
| Starts a node client (if not already started) and communicate with it. | ||
| The script file to run is passed to the constructor. | ||
| """ | ||
|
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| # create response and event queues | ||
| self.__msgq = queue.Queue() | ||
| self.__eventq = queue.Queue() | ||
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| # start node process | ||
| if os.name == "nt": | ||
| # linux subprocess module does not have STARTUPINFO | ||
| # so only use it if on Windows | ||
| si = subprocess.STARTUPINFO() | ||
| si.dwFlags |= subprocess.SW_HIDE | subprocess.STARTF_USESHOWWINDOW | ||
| self.__serverProc = subprocess.Popen(["node", scriptPath], | ||
| stdin=subprocess.PIPE, stdout=subprocess.PIPE, startupinfo=si) | ||
| else: | ||
| nodePath = NodeClient.__which("node") | ||
| print(nodePath) | ||
| self.__serverProc = subprocess.Popen([nodePath, scriptPath], | ||
| stdin=subprocess.PIPE, stdout=subprocess.PIPE) | ||
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| # start reader thread | ||
| readerThread = threading.Thread(target=NodeClient.__reader, args=(self.__serverProc.stdout, self.__msgq, self.__eventq)) | ||
| readerThread.daemon = True | ||
| readerThread.start() | ||
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| self.__debugProc = None | ||
| self.__breakpoints = [] | ||
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| # work in progress | ||
| def addBreakpoint(self, file, line): | ||
| self.__breakpoints.append((file, line)) | ||
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| # work in progress | ||
| def debug(self, file): | ||
| # TODO: msg if already debugging | ||
| self.__debugProc = subprocess.Popen(["node", "debug", file], | ||
| stdin=subprocess.PIPE, stdout=subprocess.PIPE) | ||
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| def sendCmd(self, cb, cmd): | ||
| """ | ||
| send single-line command string; no sequence number; wait for response | ||
| this assumes stdin/stdout; for TCP, need to add correlation with sequence numbers | ||
| """ | ||
| self.postCmd(cmd) | ||
| data = self.__msgq.get(block=True) | ||
| cb(data) | ||
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| def sendCmdSync(self, cmd): | ||
| """ | ||
| Sends the command and wait for the result and returns it | ||
| """ | ||
| self.postCmd(cmd) | ||
| data = self.__msgq.get(block=True) | ||
| return data | ||
|
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| def postCmd(self, cmd): | ||
| """ | ||
| Post command to server; no response needed | ||
| """ | ||
| print(cmd) | ||
| cmd = cmd + "\n" | ||
| self.__serverProc.stdin.write(cmd.encode()) | ||
| self.__serverProc.stdin.flush() | ||
|
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| def getEvent(self): | ||
| """ | ||
| Try to get event from event queue | ||
| """ | ||
| try: | ||
| ev = self.eventq.get(block=False) | ||
| except: | ||
| return None | ||
| return ev | ||
|
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||
| @staticmethod | ||
| def __readMsg(stream, msgq, eventq): | ||
| """ | ||
| Reader thread helper | ||
| """ | ||
| state = "headers" | ||
| bodlen = 0 | ||
| while state == "headers": | ||
| header = stream.readline().strip() | ||
| if len(header) == 0: | ||
| state = "body" | ||
| elif header.startswith(NodeClient.__HEADER_CONTENT_LENGTH): | ||
| bodlen = int(header[len(NodeClient.__HEADER_CONTENT_LENGTH):]) | ||
| # TODO: signal error if bodlen == 0 | ||
| if bodlen > 0: | ||
| data = stream.read(bodlen) | ||
| jsonStr = data.decode("utf-8") | ||
| jsonObj = json.loads(jsonStr) | ||
| if jsonObj["type"] == "response": | ||
| msgq.put(jsonObj) | ||
| else: | ||
| print("event:") | ||
|
There was a problem hiding this comment. Could we remove the print statement? and whoever need it will add the print themselve There was a problem hiding this comment. I will keep it for now and then remove it when the proxy raises an event which then we can add a print in the event handler. |
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| print(jsonObj) | ||
| eventq.put(jsonObj) | ||
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| @staticmethod | ||
|
There was a problem hiding this comment. Just curious why did these function There was a problem hiding this comment. they are only used here so just for encapsulation. |
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| def __reader(stream, msgq, eventq): | ||
| """ | ||
| Main function for reader thread | ||
| """ | ||
| while True: | ||
| NodeClient.__readMsg(stream, msgq, eventq) | ||
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| @staticmethod | ||
| def __which(program): | ||
| def is_executable(fpath): | ||
| return os.path.isfile(fpath) and os.access(fpath, os.X_OK) | ||
|
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| fpath, fname = os.path.split(program) | ||
| if fpath: | ||
| if is_executable(program): | ||
| return program | ||
| else: | ||
| # /usr/local/bin is not on mac default path | ||
|
There was a problem hiding this comment. Just check on my mac. The There was a problem hiding this comment. You or some installed program might have done this; it still may not be the default. |
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| # but is where node is typically installed on mac | ||
| path_list = os.environ["PATH"] + os.pathsep + "/usr/local/bin" | ||
| for path in path_list.split(os.pathsep): | ||
| path = path.strip('"') | ||
| programPath = os.path.join(path, program) | ||
| if is_executable(programPath): | ||
| return programPath | ||
| return None | ||
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So we will have to format the command ourself? or will command-formatting be supported at the proxy level?
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It will be on the proxy level I will be working on that next.