An API, or application programming interface, is a software-to-software interface that permits communication and data sharing between otherwise independent applications. All data is regarded as resources in a REST API, and each resource is identified by a distinct standard resource identifier (URI).
What does messaging mean in the context of RESTful internet services?
When a REST client wishes to send a request to the server using a REST API web service, they can do so using an HTTP application form, and the server is no different. In REST, this type of communication is known as messaging.
Why "Addressing" is important in RESTful internet services.
Addressing is the term used to describe how RESTful web services locate different sorts of resources using a URL on the REST server. Resources typically address a single or a number of resources.
Duplicate calls on the client side are known to result in problems since idempotent techniques are known to provide the same result even after the identical request has been submitted many times.
Tools like Swagger and Postman, which allow users to examine query parameters, headers, and response headers, as well as document endpoints and convert them to XML and JSON, can be used to test RESTful web services.
In RESTful web services, payloads are the request data sent via the POST or GET or PUT or DELETE technique and located in the message's body of an HTTP request.
Unified resource identifier is referred to as a URI. A URI in REST is a string which designates a web server's resource. Each resource has a distinct URI that, when used in a Http response, enables clients to target it and do actions on it. Addressing is the process of directing traffic to a resource using its URI.
RESTful APIs can be tested using a variety of software tools, including JMeter, Katalon and PostmanStudio. Sending numerous calls from the testing tool and watching how your API reacts are often steps in the testing process. You can quickly run numerous different scenarios thanks to the capability for automated testing provided by various testing solutions.
What function does a URI serve in RESTful web services?
Uniform Resource Identifier is what URI stands for. In a REST architecture, a URI identifies each resource. Locating a resource or resources on the server hosting the web service is the purpose of a URI.
HTTP Methods are also known as HTTP Verbs. They form a major portion of uniform interface restriction followed by the REST that specifies what action has to be followed to get the requested resource. Below are some examples of HTTP Methods:
GET: This is used for fetching details from the server and is basically a read-only operation.
POST: This method is used for the creation of new resources on the server.
PUT: This method is used to update the old/existing resource on the server or to replace the resource.
DELETE: This method is used to delete the resource on the server.
PATCH: This is used for modifying the resource on the server.
OPTIONS: This fetches the list of supported options of resources present on the server.
The POST, GET, PUT, DELETE corresponds to the create, read, update, delete operations which are most commonly called CRUD Operations.
What are the HTTP methods and idempotent and which are non-idempotent?
GET, HEAD, OPTIONS are safe and idempotent methods whereas PUT and DELETE methods are only idempotent. POST and PATCH methods are neither safe nor idempotent.
Can you tell what constitutes the core components of HTTP Request?
In REST, any HTTP Request has 5 main components, they are:
Method/Verb − This part tells what methods the request operation represents. Methods like GET, PUT, POST, DELETE, etc are some examples.
URI − This part is used for uniquely identifying the resources on the server.
HTTP Version − This part indicates what version of HTTP protocol you are using. An example can be HTTP v1.1.
Request Header − This part has the details of the request metadata such as client type, the content format supported, message format, cache settings, etc.
Request Body − This part represents the actual message content to be sent to the server.
What constitutes the core components of HTTP Response?
HTTP Response has 4 components:
Response Status Code − This represents the server response status code for the requested resource. Example- 400 represents a client-side error, 200 represents a successful response.
HTTP Version − Indicates the HTTP protocol version.
Response Header − This part has the metadata of the response message. Data can describe what is the content length, content type, response date, what is server type, etc.
Response Body − This part contains what is the actual resource/message returned from the server.
Define Addressing in terms of RESTful Web Services.
Addressing is the process of locating a single/multiple resources that are present on the server. This task is accomplished by making use of URI (Uniform Resource Identifier). The general format of URI is:
What are the differences between PUT and POST in REST?
PUT
POST
PUT methods are used to request the server to store the enclosed entity in request. In case, the request does not exist, then new resource has to be created. If the resource exists, then the resource should get updated.
POST method is used to request the server to store the enclosed entity in the request as a new resource.
The URI should have a resource identifier. Example: PUT /users/{user-id}
The POST URI should indicate the collection of the resource. Example: POST /users
PUT methods are idempotent.
POST methods are not idempotent.
PUT is used when the client wants to modify a single resource that is part of the collection. If a part of the resource has to be updated, then PATCH needs to be used.
POST methods are used to add a new resource to the collection.
The responses are not cached here despite the idempotency.
Responses are not cacheable unless the response explicitly specifies Cache-Control fields in the header.
