3 filesystem and basic connectivity

[Laukkala]

Description

First version of NotebookServer

• Immutable representation of saved notebook files with file management functionality
• Notebooks persisted on disk (or another implementation of file storage)
• Basic server functionality via HTTP requests
• API endpoints for other microservices to connect to
• Source of truth at any given time should be the files saved to storage

Check NBS_01 page on internal wiki for goals and design documentation on NBS_01

Below is a list of the most important Interfaces and objects of the component
Server & Servlets

• NotebookServer - Entry point to NBS_01. Defines available Servlets and assigns a path for each. Contains a Storage for file operations. Starts a Jetty server.
• HTTPServlet - Implementation of jakarta.servlet.http.HttpServlet that reads a HTTPServletRequests' body and passes the request to an Endpoint and finally sends a HTTPServletResponse back to the requester.
• FilesystemServlet - Implementation of jakarta.servlet.http.HttpServlet that parses the URL path and the body of a received HTTPServletRequest, and passes both to an Endpoint and finally sends a HTTPServletResponse back to the requester.

HTTP communication

• Request - Interface for a representation of a Request an Endpoint can process. Contains a request path, a Body and a collection of Headers
• Response - Interface for a representation of a Response that is generated by an Endpoint. Contains a HTTP response code, a Body and a collection of Headers.
• Body - Interface for a representation of the payload of a Request or a Response. Can turn itself into a string. Can be implemented to represent different kinds of structured data.
• Header - apache.http.Header

Endpoints

• EndPoint - Interface for an Endpoint that takes a Request, does an arbitrary action based on the contents of the Request and returns a Response.
• CreateNotebookEndpoint etc... - Implementations for Endpoints that do different file operations using a Storage.

Repository

• Directory - An in-memory collection of Notebooks that is capable of turning itself into JSON.
• Notebook - An in-memory collection of Paragraphs that is capable of turning itself into JSON.
• Paragraph - An in-memory representation of a paragraph containing a Script that is capable of turning itself into JSON.
• Script - An in-memory representation of user-supplied text to be run that is capable of turning iteslf into JSON.

Storage

• Storage - Interface for executing file operations on some file storage. Can create, delete, copy and move files and directories based on Paths.
• LocalFileSystemStorage - Default implementation of Storage using java.nio.Files.

Checklists

Checklists blank as this is the initial version, may still see major changes

Testing

General

• I have checked that my test files and functions have meaningful names.
• I have checked that each test tests only a single behavior.
• I have done happy tests.
• I have tested only my own code.
• I have tested at least all public methods.

Assertions

• I have checked that my tests use assertions and not runtime overhead.
• I have checked that my tests end in assertions.
• I have checked that there is no comparison statements in assertions.
• I have checked that assertions are in tests and not in helper functions.
• I have checked that assertions for iterables are outside of for loops and both sides of the iteration blocks.
• I have checked that assertions are not tested inside consumers.

Testing Data

• I have tested algorithms and anything else with the possibility of unbound growth.
• I have checked that all testing data is local and fully replaceable or reproducible or both.
• I have checked that all test files are standalone.
• I have checked that all test-specific fake objects and classes are in the test directory.
• I have checked that my tests do not contain anything related to customers, infrastructure or users.
• I have checked that my tests do not contain non-generic information.
• I have checked that my tests do not do external requests and are not privately or publicly routable.

Statements

• I have checked that my tests do not use throws for exceptions.
• I have checked that my tests do not use try-catch statements.
• I have checked that my tests do not use if-else statements.

Java

• I have checked that my tests for Java uses JUnit library.
• I have checked that my tests for Java uses JUnit utilities for parameters.

Other

• I have only tested public behavior and not private implementation details.
• I have checked that my tests are not (partially) commented out.
• I have checked that hand-crafted variables in assertions are used accordingly.
• I have tested Object Equality.
• I have checked that I do not have any manual tests or I have a valid reason for them and I have explained it in the PR description.

Code Quality

• I have checked that my code follows metrics set in Procedure: Class Metrics.
• I have checked that my code follows metrics set in Procedure: Method Metrics.
• I have checked that my code follows metrics set in Procedure: Object Quality.
• I have checked that my code does not have any NULL values.
• I have checked my code does not contain FIXME or TODO comments.