REST APIs

Question 1

What is an API?

Answer 1

A software interface that allows two applications to communicate with each other

Question 2

What does CRUD stand for in the context of REST APIs?

Answer 2

Create, Read, Update, and Delete

Question 3

What is a CRUD create operation?

Answer 3

Used to create a new variable and set its initial value

Question 4

What is a CRUD read operation?

Answer 4

Used to retrieve the value of a variable

Question 5

What is a CRUD update operation?

Answer 5

Used to change the value of a variable

Question 6

What is a CRUD delete operation?

Answer 6

Used to delete a variable

Question 7

HTTP uses _____ that map to CRUD operations

Answer 7

verbs

Question 8

HTTP _____ maps to CRUD create

Answer 8

POST

Question 9

HTTP _____ maps to CRUD read

Answer 9

GET

Question 10

HTTP _____ maps to CRUD update

Answer 10

PUT, PATCH

Question 11

HTTP _____ maps to CRUD delete

Answer 11

DELETE

Question 12

What is an HTTP URI?

Answer 12

Uniform Resource Identifier,

Indicates a particular resource available on an HTTP server

Question 13

An HTTP request will always include a ______ and a _____

Answer 13

HTTP Verb and a URI

Question 14

Do REST APIs always have to use HTTP?

Answer 14

No, although HTTP is the most common

Question 15

HTTP 1xx response codes indicate what?

Answer 15

Informational response code. request was received, continuing process

Question 16

HTTP 2xx response codes indicate what?

Answer 16

Successful response code. Request was received, understood, and accepted.

Question 17

HTTP 3xx response codes indicate what?

Answer 17

Redirection response code. Further action needs to be taken in order to complete the request

Question 18

HTTP 4xx response codes indicate what?

Answer 18

Client error response code. Request contains bad syntax or cannot be fulfilled.

Question 19

HTTP 5xx response codes indicate what?

Answer 19

Sever error response code. Server failed to fulfill an apparently valid request.

Question 20

What does REST stand for?

Answer 20

Representational State Transfer

Question 21

What are the 6 constraints of RESTful APIs?

Answer 21

1. Uniform Interface
2. Client-server
3. Stateless
4. Cacheable or non-cacheable
5. Layered system
6. Code-on-demand (optional)

Question 22

Explain the client-server constraint of REST APIs

Answer 22

Client uses API calls to access the resources on the server. Separation between client and server means they can both change and evolve independently of each other. When the client application changes or the server changes, the interface between them must not break.

Question 23

Explain the stateless constraint of REST APIs

Answer 23

API exchanges are stateless. Each API exchange is a separate event, independent of all past exchanges between the client and server. Server doesn’t store information about previous requests from the client to determine how it should respond to new requests.

If authentication is requires, client must authenticate with the server for each request it makes.

Question 24

Is TCP a stateful or stateless protocol?

Answer 24

Stateful

Establishes connections and uses sequence and acknowledgement numbers to keep track of events between servers and clients.

Question 25

Is UDP a stateful or stateless protocol?

Answer 25

Stateless

No connection is made and exchanges are not tracked

Question 26

REST APIs generally use HTTP. HTTP uses TCP (stateful). Therefore, are REST APIs stateful?

Answer 26

No. The functions of the OSI layers are different and don’t cause REST APIs to be stateful. Since TCP is L4, and REST and HTTP are L5+, they aren’t stateful because of TCP.

Question 27

Explain the Cacheable or Non-Cacheable constraint of REST APIs

Answer 27

REST APIs must support caching of data.

Not all resources have to be cacheable, but all cacheable resources must be declared as cacheable

Question 28

Does REST describe a specific API, or a set of rules about how the API should work?

Answer 28

How the API should work. REST is not a single API

Question 29

Which of the following is NOT a constraint of RESTful architecture?

a) Client-Server
b) Cacheable
c) Stateful
d) Layered System
e) Uniform Interface

Answer 29

c) Stateful

REST APIs should be stateless

Question 30

Which category of HTTP response would you expect in response to a successful request?

a) 1xx
b) 2xx
c) 3xx
d) 4xx
e) 5xx

Answer 30

b) 2xx

Question 31

HTTP verbs PUT and PATCH are equivalent to which CRUD operation?

a) C
b) R
c) U
d) D

Answer 31

c) U

Question 32

Which of the following would you expect to find as the scheme of a URI?

a) HTTPS
b) sandboxdnac.cisco.com
c) /dna/intent/api/v1/network-device
d) accept:application/xml

Answer 32

a) HTTPS

Question 33

Which of the following statements about REST APIs are true?

a) REST APIs encode data in either XML format or JSON format
b) REST APIs are typically used to communicate with an SDN application plane
c) REST APIs are typically used to communicate with an SDN data plane
d) REST APIs encode data exclusively in XML format
e) REST APIs encode data exclusively in JSON format

Answer 33

a) REST APIs encode data in either XML format or JSON format
b) REST APIs are typically used to communicate with an SDN application plane

Question 34

Which of the following APIs are typically used to enable communication between an SDN controller and the application plane? (pick many)

a) REST
b) OnePK
c) NETCONF
d) OpFlex
e) OSGi
f) OpenFlow

Answer 34

a) REST
e) OSGi

OnePK is a Cisco proprietary API for configuring network devices, OpenFlow and OpFlex are SDN models. NETCONF isn’t an API so much as a transport coordination tool that uses SSH to make config changes.

Question 35

What HTTP method is used in HTML forms but should be avoided because it includes sensitive information in the request URI?

Answer 35

GET

Question 36

Is OpFlex an imperative or declarative SDN model?

Answer 36

Declarative

Question 37

is OpenFlow an imperative or declarative SDN model?

Answer 37

Imperative

Question 38

Name a Cisco proprietary API

Answer 38

OnePK