This document discusses consuming APIs with Python. It introduces the requests library for making HTTP requests to APIs from Python. It shows examples of making GET, POST, PUT, and DELETE requests to a sample TODO list API to perform operations like retrieving, adding, updating, and deleting tasks. It then builds out these requests into reusable functions within a todo.py library module to easily interact with the API. Finally, it demonstrates using the library functions to add a task and retrieve all tasks from the API.

1. Consuming
your APIs with
Python
Michael Petychakis, Ntua

2. {
"@context":{
"schema":"http://schema.org/",
"as":"http://www.w3.org/ns/activitystreams#"
},
"@type": "schema:Person",
"schema:name": "Michael Petychakis",
"schema:jobTitle": "Phd Student",
"schema:telephone": "(425) 123-4567",
"schema:email":"mpetyx@epu.ntua.gr",
"schema:url": "http://www.mpetyx.com",
"schema:nationality":"Greece",
"as:actor":{
"@id":"http://www.twitter.com/mpetyx"
}
}
About @mpetyx

7. 958 million websites
60 trillion
web pages

8. Each API is Unique

9. http://www.slideshare.net/busaco/presentatio
ns
http://www.imdb.com/title/tt0401383/
http://www.last.fm/music/Moby
http://vimeo.com/channels/731014
Name each resource by using URLs

10. +optional parameters
(useful for pagination, partial responses,
filtering,…)
/snakes?limit=3&offset=14
/snakes?fields=name,age,description
Design accepted representations to be sent
by potential clients

11. consider existing standardized data formats
e.g., HTML, Atom, JSON,…
Accept: application/json (Digg)
/venue.json (Foursquare)
http://api.sciencemuseum.org.uk/exhibitions/
?output=json
Choose the representation(s) of the
response to be sent to client

12. https://github.com/mpetyx/apimeetup
“Clone” the code

13. # Step one for every Python app that
talks over the web.
$ pip install requests
Requirements

14. import requests
resp = requests.get('http://apiathens.herokuapp.com/tasks/')
if resp.status_code != 200:
# This means something went wrong.
raise ApiError('GET /tasks/ {}'.format(resp.status_code))
for todo_item in resp.json():
print('{} {}'.format(todo_item['id'],todo_item[title]))
GET /Tasks

15. task = {"summary": "Take out trash", "description": "" }
resp =
requests.post('http://apiathens.herokuapp.com/tasks/',
json=task)
if resp.status_code != 201:
raise ApiError('POST /tasks/
{}'.format(resp.status_code))
print('Created task. ID: {}'.format(resp.json()["id"]))
POST /Task

16. # todo.py
def get_tasks():
pass
def describe_task(task_id):
pass
def add_task(summary, description=""):
pass
def task_done(task_id):
pass
def update_task(task_id, summary, description):
pass
#todo.py

17. def _url(path):
return 'http://apiathens.herokuapp.com' + path
Helper Function

18. import requests
def get_tasks():
return requests.get(_url('/tasks/'))
def describe_task(task_id):
return requests.get(_url('/tasks/{:d}/'.format(task_id)))
def add_task(summary, description=""):
return requests.post(_url('/tasks/'), json={
'summary': summary,
'description': description,
})
def task_done(task_id):
return requests.delete(_url('/tasks/{:d}/'.format(task_id)))
def update_task(task_id, summary, description):
url = _url('/tasks/{:d}/'.format(task_id))
return requests.put(url, json={
'summary': summary,
'description': description,})
Integrated Code

19. import todo
resp = todo.add_task("Take out trash")
if resp.status_code != 201:
raise ApiError('Cannot create task: {}'.format(resp.status_code))
print('Created task. ID: {}'.format(resp.json()["id"]))
resp = todo.get_tasks()
if resp.status_code != 200:
raise ApiError('Cannot fetch all tasks: {}'.format(resp.status_code))
for todo_item in resp.json():
print('{} {}'.format(todo_item['id'], todo_item[title]))
Let’s Use our Library!

20. Thank you
Michael Petychakis
@mpetyx
<a
href="mailto:mpetyx@epu.ntua.gr?Subject=
Hello" target="_top">Drop me an e-mail</a>