What is the best way to increment an integer at a certain rate over time using a Django powered site and SQLite?

user_6947177 0
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I am trying to display a number that will increment over time that is called from a very, very simple Django database. It will be called using jinja2 templating and the number is a simple IntegerField().

However, I would like for that number to autoincrement, live without refreshing the page, multiple times throughout the day. Also, I would like for every time that the number is refreshed, for the new value to be added to the same database recording the time and date. What is the best combo or group of languages/frameworks to achieve this?

I'm starting to think that Django and Jinja2 alone are not enough to achieve this effect.

sqlite django python
3 Answers

Maybe this can help: Advanced Python Scheduler

Here's a small piece of code from their documentation to run every hour or configure as crontab:

from apscheduler.schedulers.blocking import BlockingScheduler

def some_job():
    print "Decorated job"

scheduler = BlockingScheduler()
scheduler.add_job(some_job, 'interval', hours=1)
scheduler.start()

Without knowing more of your code it's difficult to say on incremenation but I can suggest

number += 1
user_80991480

You might have a model like this to store the integer counter in the database:

class Counter(models.Model):
    counter_value = models.IntegerField()

Then you can create an instance of this model and give it an initial value of 0 using Django shell: Enter the shell by running python manage.py shell, then run the following after importing the Counter model:

Counter.objects.create(counter_value=0)

Then create a view that increments the counter (after importing your Counter model):

def increment(request):
    counter = Counter.objects.get(pk=1)
    counter.counter_value += 1
    counter.save()

Then create a url for this view (after importing the corresponding views):

urlpatterns = [
    # ...
    url(r'^increment-counter/', views.increment)
]

Now, you can run a simple Python script on the server to request the url above and cause the counter to increment every one hour for example. The script may look like this:

import time
import requests

while True:
    request.get('http://your-website-url/increment-counter')
    time.sleep(60*60) # 1 hour

This requires that you have the requests package installed.

After that, you can run this script on your server (python3 /path/to/script) to achieve what you wanted.

I kept it simple. You can, however, add complexity to satisfy your needs. You can also make the Python script run when the system starts, and you can add more functionality to it.

Note: I haven't tested the code above, but I think it is simple and works as expected.

user_22827850

Without knowing the full context, I can see two possible solutions.

1) In your Django view, load the model and calculate the the time since its beginning datetime, run a function to calculate your current auto-incrementing number, and add it to the view's context for display. Then use JavaScript to auto-update the number after the view loads in the browser. (Not a very exact method).

2) You could create a custom Django manage.py command and then use crontab to auto-execute the command at a set interval. This would allow you to store the changing number in the database. You could then use AJAX (something like jQuery's $.get() may be easy to implement) to pull that value from a Django view that serves the current number from the database. Make sure to have the AJAX script run on a set interval.

user_27147330
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