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基於tornado實現web camera近期在學習python。找了一個架構學習，我選擇的是tornado。由於其不僅僅是一個web開發架構，其還是一個server，非同步事件庫，一舉多得。
我一直在完opencv，我想接合他們兩個做一個web camera，這就開始。
在tornado中要實現對一個URL的響應，須要實現你自己的Handle。依據你對外提供的介面。實現相關的介面就好了。
以下為整個project的檔案內容：
import tornado.ioloopimport tornado.webimport tornado.genimport cv2from tornado.options import define, optionsdefine("port", default = 5000, help = "run in tornado on xxxx port", type = int)define("id", default = 0, help = "camera id", type = int)def auth(func): def _auth(self): if not self.current_user: re = {"code" : 404, "message" : "login failed!"} self.write(re) else: func(self) return _auth;class BaseHandler(tornado.web.RequestHandler): def get_current_user(self): return self.get_secure_cookie("user")class LoginHandler(BaseHandler): def get(self): self.write(‘<html><body><form action="/login" method="post">‘ ‘Name: <input type="text" name="name">‘ ‘<input type="submit" value="Sign in">‘ ‘</form></body></html>‘) def post(self): name = self.get_argument("name", "error") if name == "error": re = {"code" : 404, "message" : "login failed!"} else: self.set_secure_cookie("user", name) re = {"code" : 200, "message" : "login successfully!"} self.write(re)class CameraHandler(BaseHandler): @auth def get(self): ret, image = self.application.cap.read() if ret: self.set_header("Content-Type", "image/jpeg") self.set_header("Refresh", "1") self.set_header("content-transfer-encoding", "binary") r, i = cv2.imencode(‘.jpg‘, image) if r: self.write(bytes(i.data)) else: selt.write(‘Sorry, encode faily!‘) else: self.write(‘Sorry, get camera data faily!‘)class Application(tornado.web.Application): def __init__(self, camera_id): handlers = [(‘/camera‘, CameraHandler), (‘/login‘, LoginHandler)] self.cap = cv2.VideoCapture(camera_id) self.camera_id = camera_id; tornado.web.Application.__init__(self, handlers, debug = True ,cookie_secret = "61oETzKXQAGaYdkL5gEmGeJJFuYh7EQnp2XdTP1o") def __del__(self): self.cap.release()if __name__ == ‘__main__‘: tornado.options.parse_command_line(); app = Application(options.id) app.listen(options.port) tornado.ioloop.IOLoop.instance().start()這當中還包含了一個login的範例。我學習tornado是為了使用其做app後台，所以我實現了自己的auth的修飾器，這樣僅僅是返回一串json字元。而不是重新導向到login頁面。
在Application構造時設定裝置，在http://localhost:xxx/camera這個url上使用get方法就會返回一副圖片。
def get(self): ret, image = self.application.cap.read() if ret: self.set_header("Content-Type", "image/jpeg") self.set_header("Refresh", "1") self.set_header("content-transfer-encoding", "binary") r, i = cv2.imencode(‘.jpg‘, image) if r: self.write(bytes(i.data)) else: selt.write(‘Sorry, encode faily!‘) else: self.write(‘Sorry, get camera data faily!‘)這段代碼就是這個功能，開始的時候我僅僅是將資料拿出來就發送，沒有進行imencode。導致瀏覽器不能正確的顯示。使用Refresh實現自己主動的重新整理。
項目地址：https://git.oschina.net/zhouX/web_camera.git
無圖無真相：
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基於tornado實現web camera
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