OAS 3.0 Features

 In this blog, we will compare the differences between OAS 2.0 and OAS 3.0

• Host, base path and schemes are replaced with Servers. 
• OAS 2.0

host: dev.example.com

basePath: /v1

schemes:

- https

- http

• OAS 3.0

servers:

- url: https://dev.example.com/v1

- url: http://dev.example.com/v1

• Instead of consumes and produces, keyword content will be used
• Content allows wildcard media types. For example, image/* represents all image types
• 4 type of parameters are available now - query, path, header and cookie(new)
• Instead of securityDefinitions, new keyword is securitySchemes under components
• For Basic Authentication, type: basic was replaced with type: http and scheme: basic
• CommonMark will be used for descriptions instead of MarkDown
• type should be put under schema
• OAS 2.0

 parameters:

        - in: path

          name: meme-id

          required: true

          type: integer

• OAS 3.0

 parameters:

      - name: q

        in: query

        schema:

          type: string

          format: byte

• It uses semantic versioning (MAJOR.MINOR.PATCH)
• OAS 2.0

swagger: "2.0"

• OAS 3.0

openapi: 3.0.1

• Body and form parameters are replaced with requestBody
• OAS 2.0

paths:

  /dummy:

    post:

      description: sample

      consumes:

      - image/jpeg

      - image/gif

      produces:

      - application/xml

      parameters:

      - in: formData

        name: inputFile

        required: true

        type: file

      - in: query

        name: caption

        type: string

      responses:

        200:

          description: successful

          schema:

            type: file

• OAS3.0

/dummy:

    post:

      description: sample

      parameters:

      - name: caption

        in: query

        schema:

          type: string

      requestBody:

        content:

          image/jpeg:

            schema:

              required:

              - inputFile

              properties:

                inputFile:

                  type: string

                  format: binary

          image/gif:

            schema:

              required:

              - inputFile

              properties:

                inputFile:

                  type: string

                  format: binary

        required: true

      responses:

        200:

          description: successful

          content:

            application/xml:

              schema:

                type: string

                format: binary

• The global components/schemas will be used for common data structures
• OAS 2.0

$ref: "#/definitions/Meme"

• OAS 3.0

 $ref: '#/components/schemas/Meme'