CODEWITHSUNDEEP
python
Bobys
Bobys

Reputation: 677

Do something when internet connection is up again

I would like to implement the following concept on Python but, I'm trying to figure out the programming idea.

An image will be taken using a camera, if Internet connection is available then upload it on an FTP Server, if not keep the image stored on the drive. In the meanwhile keep doing other stuff but, when the internet connection is up again then upload it.

This could be number of images waiting to be uploaded. What do you think?

I already wrote the code to take the picture and upload it, but if there is no internet connection to upload the image on the ftp server, the script returns errors and quit. The code bellow is just some parts from my project. I have shared what I think is useful to get an idea of what Im trying to do.

def takePicture(self, image_name):
      image_path = '/home/pi/pictures/' + image_name
      interact().ftpSession(image_path, image_name)
      rLink = 'http://www.webpage.com/images/' + image_name
      print rLink
      interact().sendSms("Demo Picture " + rLink)

 def grabPicture(self):
      grab_cam = subprocess.Popen("sudo fswebcam --timestamp '%d-%m-%Y %H:%M:%S (%Z)' -r 640x480 -d /dev/v4l/by-id/usb-OmniVision_Technologies__Inc._USB_Camera-B4.09.24.1-video-index0 -q /home/pi/pictures/%m-%d-%y-%H%M.jpg", shell=True)
      grab_cam.wait()
      todays_date = datetime.datetime.today()
      image_name = todays_date.strftime('%m-%d-%y-%H%M') + '.jpg'
      return image_name

def ftpSession(self, image_path, image_name):
      session = ftplib.FTP('ftp.webpage.com','user','fg78fy87fyg')
      session.cwd('images')                         #Give the rigth folder where to store the image
      print "FTP Connection established"
      file = open(image_path,'rb')                  # file to send
      session.storbinary('STOR ' + image_name, file)     # send the file
      file.close()                                    # close file and FTP
      session.quit()
      link = 'http://www.webpage.com/images/' + image_name
      print "File has been uploaded!"
      return link

def pir():
  prevState = 0
  while True:
    time.sleep(0.1)
    currState=mcp2.input(sensorPin)
    if prevState==0 and currState==128:
      image_name = interact().grabPicture()
      #....#
      status = database().getState()
      #.....#
      if (status == 'True'):
        #Do something
      else:
            if os.path.exists('/home/pi/pictures/'+image_name):
              os.remove('/home/pi/pictures/'+image_name) #Deletes the taken picture in case of False-Alarm
              print 'File', image_name, 'has beeen deleted'

    prevState = currState
    time.sleep(1)

 Process(target=pir).start()

Upvotes: 0

Views: 373

Answers (2)

Malik Brahimi
Malik Brahimi

Reputation: 16711

I'd use urllib for a simple check to see if the internet is connected:

while True:
    try:
        urllib.urlopen('http://google.com')

        break # exit loop if connected

    except:
        print 'Establish a connection.'

    time.sleep(5) # wait five seconds


print 'Now continue' # outside of loop

Upvotes: 2

Eran Zimmerman Gonen
Eran Zimmerman Gonen

Reputation: 4507

Have a thread that tries to upload the image every once in a while (e.g. every 5 minutes or whatever amount seems to fit your needs), and keeps iterating if it fails due to lack of internet connection (use try/except).

Pseudocode:

import time
while True:
  try:
    upload_file()
  except NoConnectionException:
    time.sleep(300)

Upvotes: 0

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