Who: Alex Singer @alexjsinger Date: August 1, 2016 Event: Girls Who Code Boston This presentation covers the basics of what a REST API is, why and when it's used, and how to think about API design. It was delivered to ~20 students participating in Girls Who Code at the Boston Twitter office over the summer. The age ranges were between 15-16 years old.

1. REST APIs@alexjsinger
August 1st, 2016

2. What an API is How an API works
1 3
Where and why an
API is used
2
Goals
To understand…

3. #Servers

4. Servers
A computer on a network
Run software for specific tasks
Specialized servers for things like web pages,
emails, and databases

5. Networked systems need a way
to communicate with each other
Networked systems
communicate each other

9. Dash Button

10. Client-Server Model

11. Client-Server Model
Client Server
(laptop, phone, physical device) (…just a computer)

12. Challenges
Systems don’t “speak the same language”
Don’t expose server code
Change server code without breaking
communications
Ensure communication is secure

13. #RESTAPI
FTW

14. presentationalRe
rogrammingS
Transfer
A
P
I
pplication
nterface
tate

15. Request / response communication
HTTP
Request
https://www.twitter.com/onedirection
1. URL
2. Method
3. Header information
4. Body

16. Request / response communication
HTTP
Request
https://www.twitter.com/onedirection
Response
1. Data
2. Header information
3. Status Code

17. http://www.songzify.com/songssongssongzify.com
Request - URL (endpoint)
Unique address for a “thing” or resource on a server
Examples:
Domain Path
http://www.songzify.com/artists

18. Request - Method
A CRUD style verb to associate the endpoint with an action on the server
Method Description
GET Read resource data from the server
POST Create a resource on the server
PUT Update a resource on the server
DELETE Delete a resource from the server

19. Request - Method
A CRUD style verb to associate the endpoint with an action on the server
Method Description
GET Read resource data from the server
POST Create a resource on the server
PUT Update a resource on the server
DELETE Delete a resource from the server

20. Request - Method
A CRUD style verb to associate the endpoint with an action on the server
Method Description
GET Read resource data from the server
POST Create a resource on the server
PUT Update a resource on the server
DELETE Delete a resource from the server

21. Request - Method
A CRUD style verb to associate the endpoint with an action on the server
Method Description
GET Read resource data from the server
POST Create a resource on the server
PUT Update a resource on the server
DELETE Delete a resource from the server

22. Response - Data
Data returned by the server to the client after processing the request
The HTML content of a requested
web page
Examples:
JSON or XML of an API request

23. Response - Status Code
A numeric code to indicate the status of the request

24. Response - Status Code
A numeric code to indicate the status of the request
Common Codes:
Code Description
1xx Information i.e. 101 switching protocols
2xx Success i.e. 200 OK or 201 created
3xx Redirection i.e. 301 moved permanentely
4xx Client Error i.e. 401 unauthorized or 404 not found
5xx Server Error i.e. 500 internal server error

25. Putting it all together…
Requests use the URL, Method, Body and Headers to tell the server
what it wants to do.
GET https://api.twitter.com/1.1/statuses/user_timeline.json?
user_id=onedirection&screen_name=onedirection
Request:
Response:
Let’s take a look at the real data!

26. #DesignAPI

27. Think about features that API should expose on the server
Songzify
It should…
List all artists
List all songs by artist
List all songs
Allow an artist to be created
Allow an artist to be deleted
/artists
/songs/{artist_id}
/songs
/artists
/artists/{artist_id}
Endpoint
GET
GET
GET
POST
DELETE
Method
-
artist_id
-
artist_name
artist_id
Body

28. Dinner with an API
Exercise
Groups of 2
Think through a full dinner and
functionality a “Server” should
provide to satisfy the “Client”
Create a table showing the Endpoints,
Methods, and Body for each action
For each action, describe the expected
response from the server

29. #LearnMore

30. API Docs
API docs outline requirements for requests and response
It’s a good idea to become familiar with their structure since most REST
APIs follow the same format
Examples:
https://dev.twitter.com/rest/public
https://developer.spotify.com/web-api/endpoint-reference/
https://www.instagram.com/developer/endpoints/

31. REST APIs@alexjsinger

32. What an API is How an API works
1 3
Where and why an
API is used
2
Goals
To understand…

33. #ThankYou!