Refactoring: Added random character generator and string shuffler ser…

…vice

Controllers/PasswordController.cs

@@ -1,7 +1,7 @@
-using demo_dotnet_web_api.Interfaces;
+using DemoDotnetWebApi.Interfaces;
 using Microsoft.AspNetCore.Mvc;
 
-namespace demo_dotnet_web_api.Controllers;
+namespace DemoDotnetWebApi.Controllers;
 
 [ApiController]
 [Route("api/v1/[controller]")]

Interfaces/IPasswordGenerator.cs

@@ -1,6 +1,6 @@
-namespace demo_dotnet_web_api.Interfaces;
+namespace DemoDotnetWebApi.Interfaces;
 
 public interface IPasswordGenerator
 {
     String Generate();
-}
+}

Interfaces/IRandomCharacterGenerator.cs

@@ -0,0 +1,14 @@
+namespace DemoDotnetWebApi.Interfaces;
+
+public interface IRandomCharacterGenerator
+{
+    char GenerateUppercaseCharacter();
+
+    char GenerateLowercaseCharacter();
+
+    char GenerateDigitCharacter();
+
+    char GenerateSpecialCharacter();
+
+    char GenerateAllowedCharacter();
+}

Interfaces/IStringShuffler.cs

@@ -0,0 +1,6 @@
+namespace DemoDotnetWebApi.Interfaces;
+
+public interface IStringShuffler
+{
+    string Shuffle(string characters);
+}

Program.cs

@@ -1,10 +1,12 @@
-using demo_dotnet_web_api.Interfaces;
-using demo_dotnet_web_api.Services;
+using DemoDotnetWebApi.Interfaces;
+using DemoDotnetWebApi.Services;
 
 var builder = WebApplication.CreateBuilder(args);
 
 // Add services to the container.
-builder.Services.AddSingleton<IPasswordGenerator, PasswordGenerator>();
+builder.Services.AddTransient<IPasswordGenerator, PasswordGenerator>();
+builder.Services.AddTransient<IRandomCharacterGenerator, RandomCharacterGenerator>();
+builder.Services.AddTransient<IStringShuffler, StringShuffler>();
 
 builder.Services.AddControllers();
 // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle

Properties/launchSettings.json

@@ -9,7 +9,7 @@
     }
   },
   "profiles": {
-    "demo_dotnet_web_api": {
+    "DemoDotnetWebApi": {
       "commandName": "Project",
       "dotnetRunMessages": true,
       "launchBrowser": true,

Services/PasswordGenerator.cs

@@ -1,62 +1,44 @@
 using System.Text;
-using demo_dotnet_web_api.Interfaces;
+using DemoDotnetWebApi.Interfaces;
 
-namespace demo_dotnet_web_api.Services;
+namespace DemoDotnetWebApi.Services;
 
 public class PasswordGenerator : IPasswordGenerator
 {
-    private static readonly int PASSWORD_LENGTH = 16;
-    private static readonly String UPPERCASE_CHARACTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
-    private static readonly String LOWERCASE_CHARACTERS = "abcdefghijklmnopqrstuvwxyz";
-    private static readonly String DIGIT_CHARACTERS = "0123456789";
-    private static readonly String SPECIAL_CHARACTERS = "~`!@#$%^&*()-_=+[{]}\\|;:\'\",<.>/?";
-    private static readonly String UNION_OF_ALLOWED_CHARACTERS = UPPERCASE_CHARACTERS +
-            LOWERCASE_CHARACTERS +
-            DIGIT_CHARACTERS +
-            SPECIAL_CHARACTERS;
-    private static readonly Random random = new Random();
+    private readonly int passwordLength;
+    private readonly IRandomCharacterGenerator randomCharacterGenerator;
+    private readonly IStringShuffler stringShuffler;
 
-     /// <summary>
-     /// Generate random password
-     /// Generated password length is 16
-     /// Generated password contains at least one uppercase character
-     /// Generated password contains at least one lowercase character
-     /// Generated password contains at least one digit character
-     /// Generated password contains at least one special character
-     /// </summary>
-     /// <returns>Generated password</returns>
+    public PasswordGenerator(IRandomCharacterGenerator randomCharacterGenerator, IStringShuffler stringShuffler)
+    {
+        this.passwordLength = 16;
+        this.randomCharacterGenerator = randomCharacterGenerator;
+        this.stringShuffler = stringShuffler;
+    }
+
+    /// <summary>
+    /// Generate random password
+    /// Generated password length is 16
+    /// Generated password contains at least one uppercase character
+    /// Generated password contains at least one lowercase character
+    /// Generated password contains at least one digit character
+    /// Generated password contains at least one special character
+    /// </summary>
+    /// <returns>Generated password</returns>
     public String Generate()
     {
         var stringBuilder = new StringBuilder();
 
-        // generate at least one uppercase character
-        stringBuilder.Append(GenerateRandomCharacter(UPPERCASE_CHARACTERS));
-
-        // generate at least one lowercase character
-        stringBuilder.Append(GenerateRandomCharacter(LOWERCASE_CHARACTERS));
-
-        // generate at least one digit character
-        stringBuilder.Append(GenerateRandomCharacter(DIGIT_CHARACTERS));
+        stringBuilder.Append(randomCharacterGenerator.GenerateUppercaseCharacter());
+        stringBuilder.Append(randomCharacterGenerator.GenerateLowercaseCharacter());
+        stringBuilder.Append(randomCharacterGenerator.GenerateDigitCharacter());
+        stringBuilder.Append(randomCharacterGenerator.GenerateSpecialCharacter());
 
-        // generate at least one special character
-        stringBuilder.Append(GenerateRandomCharacter(SPECIAL_CHARACTERS));
-
-        for (int i = 4; i < PASSWORD_LENGTH; i++)
+        for (int i = 0; i < passwordLength - 4; i++)
         {
-            // generate random character from union of allowed characters
-            stringBuilder.Append(GenerateRandomCharacter(UNION_OF_ALLOWED_CHARACTERS));
+            stringBuilder.Append(randomCharacterGenerator.GenerateAllowedCharacter());
         }
 
-        // shuffle generated characters
-        IList<String> ch = stringBuilder.ToString().Split("").ToList();
-        ch.Shuffle();
-
-        // return generated password
-        return string.Join("", ch);
-    }
-
-    private char GenerateRandomCharacter(String characters)
-    {
-        return characters.ElementAt(random.Next(characters.Length));
+        return stringShuffler.Shuffle(stringBuilder.ToString());
     }
-}
+}

Services/RandomCharacterGenerator.cs

@@ -0,0 +1,50 @@
+using DemoDotnetWebApi.Interfaces;
+
+namespace DemoDotnetWebApi.Services;
+
+public class RandomCharacterGenerator : IRandomCharacterGenerator
+{
+    private readonly String uppercaseCharacters;
+    private readonly String lowercaseCharacters;
+    private readonly String digitCharacters;
+    private readonly String specialCharacters;
+    private readonly String allowedCharacters;
+    private readonly Random random = new Random();
+
+    public RandomCharacterGenerator()
+    {
+        uppercaseCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+        lowercaseCharacters = "abcdefghijklmnopqrstuvwxyz";
+        digitCharacters = "0123456789";
+        specialCharacters = "~`!@#$%^&*()-_=+[{]}\\|;:\'\",<.>/?";
+        allowedCharacters = uppercaseCharacters +
+            lowercaseCharacters +
+            digitCharacters +
+            specialCharacters;
+    }
+
+    public char GenerateAllowedCharacter()
+    {
+        return allowedCharacters.ElementAt(random.Next(allowedCharacters.Length));
+    }
+
+    public char GenerateDigitCharacter()
+    {
+        return digitCharacters.ElementAt(random.Next(digitCharacters.Length));
+    }
+
+    public char GenerateLowercaseCharacter()
+    {
+        return lowercaseCharacters.ElementAt(random.Next(lowercaseCharacters.Length));
+    }
+
+    public char GenerateSpecialCharacter()
+    {
+        return specialCharacters.ElementAt(random.Next(specialCharacters.Length));
+    }
+
+    public char GenerateUppercaseCharacter()
+    {
+        return uppercaseCharacters.ElementAt(random.Next(uppercaseCharacters.Length));
+    }
+}

Services/StringShuffler.cs

@@ -0,0 +1,25 @@
+using DemoDotnetWebApi.Interfaces;
+
+namespace DemoDotnetWebApi.Services;
+
+public class StringShuffler : IStringShuffler
+{
+    private readonly Random random = new Random();
+
+    public string Shuffle(string characters)
+    {
+        IList<string> list = characters.Split("").ToList();
+        int n = list.Count;
+
+        while (n > 1)
+        {
+            n--;
+            int k = random.Next(n + 1);
+            string value = list[k];
+            list[k] = list[n];
+            list[n] = value;
+        }
+
+        return string.Join("", list);
+    }
+}

ShuffleExtension.cs

@@ -1,4 +1,4 @@
-namespace demo_dotnet_web_api;
+namespace DemoDotnetWebApi;
 
 public static class ShuffleExtension
 {

demo-dotnet-web-api.csproj

@@ -4,7 +4,7 @@
     <TargetFramework>net6.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
-    <RootNamespace>demo_dotnet_web_api</RootNamespace>
+    <RootNamespace>DemoDotnetWebApi</RootNamespace>
   </PropertyGroup>
 
   <ItemGroup>