Introducing API Flashcards
What is a REST API?
a programming interface that communicates over http while adhering to the principles of the REST architectural style
What are the six principles of the REST architecture style
Client-Server Stateless Cache Uniform Interface Layered System Code-On-Demand (Optional)
What are the protocols of HTTP
HTTP requests/responses
HTTP verbs
HTTP status codes
HTTP headers/body
What are the four major componets of an API
Uniform Resource identifier (URI)
Http method
Header
Body
What is a Uniform Resource identifier (URI) or Uniform Resource Locator (URL)
identifes which resource the client wants to manipulate
What is the syntax of a URL
Scheme
Authority
Path
Query
What is a scheme in a URL
Specifies which HTTP protocol should be used
What are the two options for scheme in a url
http
https
What are the three reasons for using API
Automaton tasks
Data integration
Functionality
What is a benefit of syncrhonous API design
enables the app to receive data immediately
What is a con of synchronous design
Bottlenecks can occur because of waiting for data to come
What is a Remote Procedure Call (RPC)
a request-response model that enables an application to make a procedure call to another app
How does RPC work
client is usually unaware that the procedure request is being executed remotely because the request is made to a layer that hides those details. As far as the client is concerned, these procedure calls are simply actions that it wants to perform. In other words, to a client, a Remote Procedure Call is just a method with arguments and when it’s called, the method gets executed and the results get returned.
What is Simple Object Access Protocol (SOAP)
a messaging protocol for communicating between applications that may be on different platforms or built with different programming languages. It is an XML-based protocol that was developed by Microsoft.
What are the three characteristics of SOAP
independent
Extensible
Neutral
What is REpresentational State Transfer (REST)
A modern type of API
Name the six constraints applied to elements with the architecture
Client-Server Stateless Cache Uniform Interface Layered System Code-On-Demand
Describe Client-Server of RESTFUL api
The client and server should be independent of each other, enabling the client to be built for multiple platforms and simplifying the server side components.
Describe Stateless constraint of an RESTFUL api
Requests from the client to the server must contain all of the information the server needs to make the request. The server cannot contain session states.
Describe the CACHE constraint of RESTFUL api
Responses from the server must state whether the response is cacheable or non-cacheable. If it is cacheable, the client can use the data from the response for later requests.
Describe the Layered system contraint in RESTFUl api
The system is made up of different hierarchical layers in which each layer provides services only to the layer above it. As a result, it consumes services from the layer below.
Describe Code-on-demand constraint in RESTFUl api
references the fact that information returned by a REST service can include executable code (e.g., javascript) or links to such code, intended to usefully extend client functionality.
Name the four principle of Uniform interface
Identification of resources
Manipulation of resources through representations:
Self-descriptive messages
Hypermedia as the engine of application state
What is an REST APi
programming interface that communicates over HTTP while adhering to the principles of the REST architectural style.
What are the conceots if the HTTP protocol
HTTP requests/responses
HTTP verbs
HTTP status codes
HTTP headers/body
What is a rest api request
are essentially HTTP requests that follow the REST principles. These requests are a way for an application (client) to ask the server to perform a function. Since it is an API, these functions are predefined by the server and must follow the provided specification.
What is a REST API request made up of
Uniform Resource Identifier (URI)
HTTP Method
Header
Body
What is a Inform Resource Identifier (URI)
sometimes referred to as Uniform Resource Locator (URL), identifies which resource the client wants to manipulate.
What are the four parts of a (URI)
Scheme
Authority
Path
Query
Identify each part of a (URI)
http: //localhost8080 /v1/books/ ?q=DevNet
Scheme - Authority - Path - Query
What is a scheme
The scheme specifies which HTTP protocol should be used. For a REST API, the two options are:
http – connection is open
https – connection is secure
What is an authority
The authority, or destination, consists of two parts that are preceded with two forward slashes ( // ):
Host
Port
What is PATH
For a REST API, the path is usually known as the resource path, and represents the location of the resource, the data or object, to be manipulated on the server. The path is preceded by a slash ( / ) and can consists of multiple segments that are separated by a slash ( / ).
What is the Query
The query, which includes the query parameters, is optional. The query provides additional details for scope, for filtering, or to clarify a request. If the query is present, it is preceded with a question mark ( ? ). There isn’t a specific syntax for query parameters, but it is typically defined as a set of key-value pairs that are separated by an ampersand ( & ). For example:
http://example.com/update/person?id=42&email=person%40example.com
What is an http request method
defines a set of request methods to indicate the desired action to be performed for a given resource
What are all of the HTTP methods
POST GET PUT PATCH DELETE
What odes the post http method do
Create - Create a new object or resource
What does the GET http method do
READ - Retrieve resource details from the system
What does the PUT http method do
Update - Replace or update an existing resource
What does the DELETE http method do
DELETE - Remove a resource from the system
What is a request header
include additional information that doesn’t relate to the content of the message.
What are entity headers
Entity headers are additional information that describes the content of the body of the message.
What is the body
contains the data pertaining to the resource that the client wants to manipulate.
Describe 1XX status codes
Inforamtional - are for informational purposes, indicating that the server received the request but is not done processing it. The client should expect a full response later. These responses typically do not contain a body.
Describe 2XX status codes
success- the server received and accepted the request. For synchronous APIs, these responses contain the requested data in the body if applicable. For asynchronous APIs, the responses typically do not contain a body and the 2xx status code is a confirmation that the request was received but still needs to be fulfilled.
Describe 3XX status codes
redirection - the client has an additional action to take in order for the request to be completed. Most of the time a different URL needs to be used. Depending on how the REST API was invoked, the user might be automatically redirected without any manual action.
Describe the status code 4XX
client error - the request contains an error, such as bad syntax or invalid input, which prevents the request from being completed. The client must take action to fix these issues before resending the request.
Describe the status 5XX status codes
Server error - the server is unable to fulfill the request even though the request itself is valid. Depending on which particular 5xx status code it is, the client may want to retry the request at a later time.
What does the status code 200 mean
OK - Request was successfully and typically contains a payload (body)
What does the 201 code mean
Created - Request was fulfilled and the requested resource was created
What does the status code 202 mean
Accepted - Request has been accepted for processing but is not complete
What does the status code 400 mean
Bad request - Request will not be processed due to an error with the request
What does the status code 403 mean
Forbidden - Request was understood but has been rejected by the server
What does the status code 404 mean
Not found - Request cannot be fulfilled because the resource path of the request was not found on the server
What does the status code 500 mean
Internal Server Error - Request cannot be fulfilled due to a server error
What does the status code 503 mean
Service Unavailable - Request cannot be fulfilled because currently the server cannot handle the request
