sandwiches.py

from typing import Iterable
from airtable import airtable

# Don't know what Airtable is?  It's basically Excel for developers.
# It's super cool.
# Check it out: airtable.com
table = airtable.Airtable('API_KEY', 'OTHER_KEY')


# Okay, so we want to fetch all results in a table.  Problem is, you know, pagination:
# this table has hundreds of records but we can only get like fifty per call.
# Here's how we abstract that out!
def fetch_all_records(table_name: str) -> Iterable:
    # Grab the first page.  The page has two fields we care about:
    # 1. records — aka the good stuff
    # 2. offset — a cursor to the next page.
    response = table.get(table_name)

    # If there's a cursor to the next page...
    while 'offset' in response:
        # Yield all the records on this page.
        # Records look like this:
        # {'fields': {'name': 'Salumi', 'city': 'Seattle', 'rating': 5}, 'id': 'as890ops'}
        for record in response['records']:
            yield record

        # Grab the next page and repeat the process.
        response = table.get('Finished', offset=response['offset'])

    # Otherwise, yield all the records and then we're done!
    for record in response['records']:
        yield record


# Now, to access all the records, we don't have to care about:
# 1. How many records are in a page
# 2. How to get to the next page
# 3. How to traverse the page.
# All of that is abstracted away by the generator!
# So we can just iterate through all of them like this:
for record in fetch_all_records('Sandwiches'):
    print(record['fields']['Name'])


# And generators are lazy, too, so if we just want the first twenty items
# we can do so without worrying about premature pagination:
for i, record in enumerate(fetch_all_records('Sandwiches')):
    if i > 20:
        break
    print(record['fields']['Name'])


# Generators aren't great for everything.
# For instance, operating on an entire corpus of an iterable is rough:
# this code will force you to refetch the entire list over and over again.
best_rating = max([record['fields']['Rating'] for record in fetch_all_records('Sandwiches')])
worst_rating = min([record['fields']['Rating'] for record in fetch_all_records('Sandwiches')])


# In such a case, you're better off casting the generator to a list.
# (But you might be *best* off with a different approach entirely.)
all_records = list(fetch_all_records('Sandwiches'))
best_rating = max([record['fields']['Rating'] for record in all_records])
worst_rating = min([record['fields']['Rating'] for record in all_records])


# Ultimately, generators are the best kind of Python feature:
# 1. They make it easier to understand code.
# 2. They make it easier to write code.
# 3. They're just *neat*.
for record in fetch_all_records('Sandwiches'):
    # Gotta find a great sandwich in Seattle!
    if record['fields']['Rating'] > 4 and record['field']['city'] == 'Seattle':
        print(record['fields']['Name'])
        break