Data Exchange Methods and Systems

Data Exchange Methods and Systems

1. REST Principles

   • Separation of Client and Server
     • The implementation of the client and the implementation of the server can be done independently without each knowing about the other.
   • Statelessness
     • The server does not need to know anything about what state the client is in and vice versa
   • Communication between Client and Server
     • Clients send requests to retrieve or modify resources, and servers send responses to these requests.
   • Making Requests
     • Requires that a client make a request to the server in order to retrieve or modify data on the server
   • HTTP Verbs
     • GET
       • Retrieve a specific resource (by id) or a collection of resources
     • POST
       • Create a new resource
     • PUT
       • Update a specific resource (by id)
     • DELETE
       • Remove a specific resource by id
   • HTTP Response Codes
     • 200 (OK)
       • Successful HTTP requests
     • 201 (CREATED)
       • An HTTP request that resulted in an item being successfully created
     • 204 (NO CONTENT)
       • Successful HTTP requests, where nothing is being returned in the response body
     • 400 (BAD REQUEST)
       • Request cannot be processed because of bad request syntax, excessive size, or another client error.
     • 403 (FORBIDDEN)
       • Client does not have permission to access this resource
     • 404 (NOT FOUND)
       • Resource could not be found at this time. It is possible it was deleted, or does not exist yet
     • 500 (INTERNAL SERVER ERROR)
       • Generic answer for an unexpected failure if there is no more specific information available

2. REST vs SOAP vs GraphQL

   • REST
     • Representational State Transfer
     • A REST API is an application programming interface (API or web API) that conforms to the constraints of REST architectural style and allows for interaction with RESTful web services
     • Positives
       • Easy to understand and learn, due to its simplicity
       • Being able to organize complicated applications & makes it easy to use resources
       • The high load can be managed with help out of HTTP proxy server & cache
       • REST API is easy to explore and discover
       • It makes it simple for new clients to work on other applications
       • Use standard HTTP procedure call- outs to retrieve data and requests
       • REST API depends on codes, can use it to synchronize data with a website without any complications
       • Brings flexibility formats by serializing data in XML or JSON format
     • Negatives
       • Lack of state
       • Last of security
   • SOAP
     • SOAP is a standard communication protocol system that permits processes using different operating systems like Linux and Windows to communicate via HTTP and its XML.
       • SOAP based APIs are designed to create, recover, update and delete records like accounts, passwords, leads, and custom objects.
     • Positives
       • Language, platform, and transport independent (REST requires use of HTTP)
       • Works well in distributed enterprise environments
       • Standardised
       • Built-in error handling
       • High security
     • Negatives
       • Poorer performance
       • more complexity
       • Less flexibility
     • Simple Object Access Protocol
   • GraphQL
     • A query language (that's what the “QL” stands for) for APIs and a runtime for fulfilling those queries with your existing data
     • Positives
       • network performance improvements
       • loose coupling between client and server
       • strong typing
       • developer tooling
     • Negatives
       • everything is POST
       • GraphQL servers become big and bloated
       • Becoming too dependent on the Apollo client

3. JSON vs XML

   • JSON
     • Data Structures
       • Object {}
         • an abstract data type created by a developer
       • The data are in key, value pairs
         • a field, or combination of fields, in a database table used to retrieve and sort rows in the table based on certain requirements
       • Array []
         • a data structure consisting of a collection of elements (values or variables), each identified by at least one array index or key.
       • No quotes if element is a numeric value
         • An element is a single part of a larger group
       • "" if element is a character
         • An element is a single part of a larger group
       • commas separate pieces of data
         • represents the piece of information you find in one cell of a data table
     • Positives
       • Shorter in Length
       • Lower character count
       • Quick and easy to read
       • Easy to phrase
     • Negatives
       • Less secure than XML
       • No display capabilities
       • Only supports text and numbers
       • Not very compatible with HTML
   • XML
     • Data Structures
       • Parent-Child Structure
         • Root element
           • Child element
             • Subchild
               • etc.
       • Root element
         • One only per document
         • It encloses all the other elements and is therefore the sole parent element to all the other elements
         • eg. <bookstore>
       • Element
         • Child of the root or child of a child
         • everything from (including) the element's start tag to (including) the element's end tag.
         • can contain
           • text
           • attributes
           • other elements
           • mixture of all
       • Attribute
         • Belong to an element
         • Attributes are designed to contain data related to a specific element
         • Similar to a class or id in HTML
     • Positives
       • Supports various data types
       • More secure than JSON
       • Extremely compatible with HTML
       • Offers display data
     • Negatives
       • Lengthy
       • Less readable
       • Doesn’t support arrays
       • Difficult to phrase