Difference between revisions of "W3911 Sudoku Server"

Revision as of 08:20, 7 October 2021

Within these castle walls be forged Mavens of Computer Science ...

— Merlin, The Coder

Background A Sudoku board is made up of nine boxes. Boxes (container for nine cells) are listed from top-to-bottom, left-to-right indexed from zero. Cells are listed from top-to-bottom, left-to-right, indexed from zero. All valid payloads and responses must use well-formed JSON. “cells” is returned as follows: “cells”: [[<nine values from top-left>], [<nine values from top-middle>], …]

End Points

POST /games?difficulty=<difficulty>
Creates a new game and associated board

   Parameters: 
   difficulty: easy | medium | hard | hell

   Body: none

   Status code: 201 Created

   Response: ID (integer) of newly created game
   {"id":<id>}
   
   {"id": 728134}

   Errors:
   
   {{{errors}}}

GET /games/<id>/cells
Returns the current cells for the specified game

   Parameters: 
   none

   Body: none

   Status code: 200 OK

   Response: Cells
   {"id":<id>}
   
   {"id": 728134}

   Errors:
   
   {{{errors}}}

PUT /games/<id>/cells/<boxIndex>/<cellIndex>
Place specified value at in game at boxIndex, cellIndex

   Parameters: 
   none

   Body: value (null for removing value)

   Status code: 200 OK

   Response: none
   
   none

   Errors:
   
   {{{errors}}}

JSON Encoding[edit]

JSON Decoding[edit]

Issue Request from Client to Server[edit]

import Foundation                                                                                                                                                                                                                           
import FoundationNetworking                                                                                                                                                                                                                 
 
// Form the request                                                                                                                                                                                                                                           
var request = URLRequest(url: URL(string: "https://language-server.codermerlin.com/now")!)                                                                                                                                                  
request.httpMethod = "GET"

// Execute synchronously (uses extension in code below)                                                                                                                                                                                                                 
let (data, response, error) = URLSession.shared.syncRequest(with: request)
if let data = data,                                                                                                                                                                          
   let string = String(data: data, encoding: .utf8) {                                                                                                                                     
   print(string)                                                                                                                                                                            
} else if let error = error {
    print("Error: \(error)")
} else {
    print("An unexpected error occurred.")
}

// Reference: https://stackoverflow.com/questions/26784315/can-i-somehow-do-a-synchronous-http-request-via-nsurlsession-in-swift
extension URLSession {
   func syncRequest(with request: URLRequest) -> (Data?, URLResponse?, Error?) {
      var data: Data?
      var response: URLResponse?
      var error: Error?
      
      let dispatchGroup = DispatchGroup()
      let task = dataTask(with: request) {
         data = $0
         response = $1
         error = $2
         dispatchGroup.leave()
      }
      dispatchGroup.enter()
      task.resume()
      dispatchGroup.wait()
      
      return (data, response, error)
   }  
}

@@ Line 46: / Line 46: @@
 |initialCode=import Foundation
-struct Cell: Codable {
+let board = Board()
-    let value: Int?
-}
-let cell = Cell(value: 17)
 let encoder = JSONEncoder()
-guard let data = try? encoder.encode(cell),
+guard let data = try? encoder.encode(board),
        let json = String(data: data, encoding: .utf8) else {
      fatalError("Failed to encode data into json.")
 }
 print(json)
+// Structure definitions
+struct Cell: Codable {
+    let value: Int?
+}
+struct Box: Codable {
+     let cells: [Cell]
+     init() {
+         var cells = [Cell]()
+         for cellIndex in 0 ..< 9 {
+             cells.append(Cell(value: cellIndex))
+         }
+         self.cells = cells
+     }
+}
+struct Board: Codable {
+     let board: [Box]
+     init() {
+         var board = [Box]()
+         for _ in 0 ..< 9 {
+             board.append(Box())
+         }
+         self.board = board
+     }
+}
 }}
 === JSON Decoding ===