operating raspi camera

cat_camera.py

#! /usr/bin/env python3

import os
import time

PIC = False
CV2 = False

try:
    from picamera import PiCamera
    PIC = True
except Exception:
    pass

if not PIC:
    try:
        import cv2
        cap = cv2.VideoCapture(0)
        if not cap.isOpened():
            raise(Exception("Can not open camera through cv2"))
        CV2 = True
    except Exception:
        pass

if not PIC and not CV2:
    raise(Exception("Can not open camera through cv2"))

from datetime import datetime

base = os.path.dirname(os.path.realpath(__file__))
counter = 0

def cat_cv2(name):
    cap = cv2.VideoCapture(0)
    ret, frame = cap.read()
    cv2.imwrite(name, frame)
    cap.release()

def cat_pic(name):
    with PiCamera() as c:
        c.start_preview()
        time.sleep(2)
        c.capture(name)

def cat():
    global counter
    counter += 1
    name = os.path.join(base, "pics", "%s_%s.jpg" % (time.time(), str(datetime.now())))
    
    if CV2:
        cat_cv2(name)
    elif PIC:
        cat_pic(name)
   
    return name

if __name__ == "__main__":
    print(cat())