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Guled Ahmed
Guled Ahmed
12,806 Points

Is it possible to organize posts by date using Jinja?

I recently tried to implement a system in which posts are grouped by date like so:


post 1

post 2


post 3

post 4

June 2

post 5

nth post

My initial attempts included creating a new Date model with a date property with the default value of datetime.datetime.today() and tried to pass that to my webpage along with the stream and try to make the dates as an outer loop and the stream as an inner loop and tried to evaluate posts under a specific date in this fashion. This method did not work at all. I was wondering if anyone know how to either organize this using database tables or jinja.

Regards, Guled

1 Answer

Dan Johnson
Dan Johnson
40,533 Points

For Jinja2 you have sorting options in the form of built-in filters:

You could select whatever date attribute you want to sort on.

For a general solution I threw this together. It's far from optimal but maybe it could give you some ideas for a better one:

Basic Post Model

class Post(Model):
  created = DateTimeField(default=datetime.datetime.now)  
  content = TextField()

  def select_posts_from(model, days_ago):
    today = datetime.datetime.now()

    upper_limit = today - datetime.timedelta(days=days_ago-1)
    lower_limit = today - datetime.timedelta(days=days_ago)

    clear = {attr: 0 for attr in ["hour","minute","second","microsecond"]}
    upper_limit = upper_limit.replace(**clear)
    lower_limit = lower_limit.replace(**clear)

    upper_query = model.created < upper_limit
    lower_query = model.created >= lower_limit

    return model.select().where(upper_query & lower_query).order_by(Post.created.desc())

  class Meta:
    database = DATABASE

Index Route

from collections import OrderedDict

# ...

def index():
  dates = OrderedDict()
  dates["Today"] = Post.select_posts_from(days_ago=0)
  dates["Yesterday"] = Post.select_posts_from(days_ago=1) 
  dates["Two Days Ago"] = Post.select_posts_from(days_ago=2)

  return render_template("index.html", dates=dates)

Index Template

<!DOCTYPE html>
  <meta charset="utf-8">
  <title>Post Sort Example</title>
  {% for date in dates %}
  <h2>{{ date }}</h2>
    {% for post in dates[date] %}
      <p>{{ post.content }}</p>
      <i>Created On: {{ post.created }}</i>
    {% endfor %}
  {% endfor %}
Guled Ahmed
Guled Ahmed
12,806 Points

Thank you for your help Dan. I appreciate it.

Guled Ahmed
Guled Ahmed
12,806 Points

Jinja's groupby feature is the most optimal solution.

Dan Johnson
Dan Johnson
40,533 Points

Swapped to timedeltas for adjustment which should fix any issues with longer ranges of time. Feel free to yell at me if you see anything else broken.