HTTP Web Services requests GET, POST, PUT, DELETE

Question 1

Service Class

Answer 1

Encapsulates the functionality of code that works as a unit or provides a specific business purpose.

Question 2

Types of HTTP Methods

Answer 2

1. Safe - GET (Not Safe - POST, PUT, DELETE).

2. Idempotent - GET, PUT, DELETE (Not Idempotent - POST).

Question 3

Safe HTTP Method

Answer 3

A request that does not change the server.

Question 4

Idempotent HTTP Method

Answer 4

A request that has the same result regardless of how many times it is completed.

Question 5

HTTP Methods - GET Usage

Answer 5

Generally used to retrieve web pages to display (images, documents, stylesheets, script files, search pages).

Question 6

GET Method Characteristics

Answer 6

GET requests are easily bookmarked because the parameters are in the URL. GET does not change the state on the server and has the same result each time it is repeated so it is Safe Idempotent.

Question 7

Serialization

Answer 7

Transforming a Java Object to a string representation of the object, JSON. Object → JSON

Question 8

Deserialization

Answer 8

Transforming a string representation of an object, JSON, into a Java Object. JSON → Object

Question 9

HTTP Methods - POST Usage

Answer 9

Used when:

1. Data must be secure (credit card number, password, etc.)
2. Data is too large for the URL.
3. When the request is asking to add something on the server.

Question 10

HTTP Methods - POST Usage

Answer 10

1. HTTP POST requests cannot be bookmarked or sent with the browser directly.
2. Post modifies the server and leaves the server in a different state each time the same request is repeated, so it is Not Safe Not Idempotent.
3. POST transfers data in the message body instead of the URL.
4. While HTTPS encrypts the message body, it cannot encrypt the URL.

Question 11

HTTP Methods - PUT Usage

Answer 11

Used to:

1. Update existing data.
2. Meant to overwrite the entire record with the new values.

Question 12

HTTP Methods - PUT Characteristics

Answer 12

1. Cannot be bookmarked or sent with the browser directly.
2. Indicates that the request will update existing data on the server.
3. Put changes the state on the server but the state remains the same if the same request is repeated multiple times, so it is Not Safe Idempotent

Question 13

HTTP Methods - DELETE Usage

Answer 13

Used to:

1. Remove existing data from the server.
2. Only requires the entity’s id, so parameters are sent in the query string.

Question 14

HTTP Methods - DELETE Characteristics

Answer 14

1. Cannot be bookmarked or sent with the browser directly.
2. This indicates that the request will remove existing data from the server.
3. Delete changes the state of the server but the state remains the same if the request is repeated multiple times, so it is Not Safe Idempotent.