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| #!/usr/bin/python | |
| # Equivalent of "tail -f" as a webpage using websocket | |
| # Usage: webtail.py PORT FILENAME | |
| # Tested with tornado 2.1 | |
| # Thanks to Thomas Pelletier for it's great introduction to tornado+websocket | |
| # http://thomas.pelletier.im/2010/08/websocket-tornado-redis/ | |
| import tornado.httpserver | |
| import tornado.websocket | |
| import tornado.ioloop | |
| import tornado.web | |
| import sys | |
| import os | |
| PORT = int(sys.argv[1]) | |
| FILENAME = sys.argv[2] | |
| LISTENERS = [] | |
| TEMPLATE = """ | |
| <!DOCTYPE> | |
| <html> | |
| <head> | |
| <title>WebTail: %s</title> | |
| </head> | |
| <body> | |
| <div id="file"></div> | |
| <script type="text/javascript" charset="utf-8"> | |
| function write_line(l) { | |
| document.getElementById('file').innerHTML += '<p>' + l + '</p>'; | |
| } | |
| if ("MozWebSocket" in window) { | |
| WebSocket = MozWebSocket; | |
| } | |
| if (WebSocket) { | |
| var ws = new WebSocket("ws://%s/tail/"); | |
| ws.onopen = function() {}; | |
| ws.onmessage = function (evt) { | |
| write_line(evt.data); | |
| }; | |
| ws.onclose = function() {}; | |
| } else { | |
| alert("WebSocket not supported"); | |
| } | |
| </script> | |
| </body> | |
| </html> | |
| """ | |
| tailed_file = open(FILENAME) | |
| tailed_file.seek(os.path.getsize(FILENAME)) | |
| def check_file(): | |
| where = tailed_file.tell() | |
| line = tailed_file.readline() | |
| if not line: | |
| tailed_file.seek(where) | |
| else: | |
| print "File refresh" | |
| for element in LISTENERS: | |
| element.write_message(line) | |
| class TailHandler(tornado.websocket.WebSocketHandler): | |
| def open(self): | |
| print "WebSocket open" | |
| LISTENERS.append(self) | |
| def on_message(self, message): | |
| pass | |
| def on_close(self): | |
| print "WebSocket close" | |
| try: | |
| LISTENERS.remove(self) | |
| except: | |
| pass | |
| class MainHandler(tornado.web.RequestHandler): | |
| def get(self): | |
| self.write(TEMPLATE % (FILENAME, self.request.host)) | |
| application = tornado.web.Application([ | |
| (r'/', MainHandler), | |
| (r'/tail/', TailHandler), | |
| ]) | |
| if __name__ == '__main__': | |
| http_server = tornado.httpserver.HTTPServer(application) | |
| http_server.listen(PORT) | |
| tailed_callback = tornado.ioloop.PeriodicCallback(check_file, 500) | |
| tailed_callback.start() | |
| io_loop = tornado.ioloop.IOLoop.instance() | |
| try: | |
| io_loop.start() | |
| except SystemExit, KeyboardInterrupt: | |
| io_loop.stop() | |
| tailed_file.close() |
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