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11,393 PointsDude.. you completely lost it in this video... calm down
All the sudden Keneth starts going without even explaining what he is doing... Treehouse, cmon, please....
7 Answers
Shyam Gupta
7,757 PointsI also spent a considerable time to understand what was going on, below explanation should help
Note:
json.loads() converts/decodes JSON data into Python dictionary
json.dumps() converts Python dictionary to JSON
The request.form object is an immutable dictionary.
Cookies can be thought of as key-value pairs that we may or may not receive by default from return visitors. When a user makes choices, we create or update their cookie to reflect these changes, and when a user requests our site, we check to see whether a cookie exists and read as much of the unspecified information from this as possible.
Step1- Define a function to retrieve the cookie if it exists.
def get_saved_data():
try:
data = json.loads(request.cookies.get(‘cookie_name’) ##loads converts JSON to a Python dictionary.
except TypeError:
data = {} #Return empty dictionary if cookie does not exist.
return data
Step2 - Create a response variable We will wrap a make_response() call around our render_template() or redirect call instead of returning the rendered template directly. This means that our Jinja templates will be rendered, and all the placeholders will be replaced with the correct values, but instead of returning this response directly to our users, we will load it into a variable so that we can make some more additions to it.
response = make_response(redirect(url_for(‘index’)))
Step3: Set cookie expiration (This wasnt part of the lecture, but good to know) Once we have this response object, we will create a datetime object with a value of 365 days (or whatever duration) from today's date
expires = datetime.datetime.now() + datetime.timedelta(days=365)
Step 4: Check if a cookie already exists & retrieve it
data = get_saved_data()
Step 5: If the cookie exists, only update the values that have changed
data.update(dict(request.forms.items()))
Step 6: Set the cookie
response.set_cookie(‘cookie_name’, json.dumps(data), expires=expires )
return response
Chris Freeman
Treehouse Moderator 68,441 PointsMoved comment to answer
Aleksandra Landeker
1,498 PointsThank you, Shyam! Very helpful comments. :)
Mel Rumsey
Treehouse ModeratorThis is what I needed. Thank you Shyam for taking the time to post this
dojewqveaq
11,393 PointsSorry about minor rant.
At 5:15 on, what is saves=data? From that point video evolved way too rapidly...Not much was explained
Juris Jaundzeikars
Python Web Development Techdegree Student 671 PointsKenneth is mad here
agigryms
2,569 PointsGreat explanations, Shyam, they helped a lot!
Kortney Field
14,091 PointsThis video might be better if it was broken down into 10 mini lessons. Went a bit over my head.
Chris Freeman
Treehouse Moderator 68,441 PointsThere is a lot of information covered at that point in the video. From the Flask docs, render_templates
takes a template as an argument followed by any number of keyword arguments which will be added to the template context. So, assigning saves
makes saves
available in the template. The next area is how to handle getting the cookie information, updating it, and then passing the updated cookie back to the browser.
Post back if you need more clarification.
Brian Ko
10,174 PointsThank you, Shyam! That was a great explanation of the video and helped me a lot! Are cookies stored on the browser per domain or per URL? Is that why we need to make sure to use .update()
? Because there might be other cookies from other pages that will get overwritten if we don't use update()
?
Chris Freeman
Treehouse Moderator 68,441 PointsChris Freeman
Treehouse Moderator 68,441 PointsWhat do mean by "lost it" and "calm down"? Can you reference time points in the video?