When handling tokens in .NET applications, it's essential to avoid logging them in full due to the potential exposure of sensitive information. A best practice is to redact tokens before logging by showing only a prefix and/or suffix.
Here’s a robust approach:
Redact tokens safely: Display only the first few and last few characters of the token, separated by ellipses (...). If the token is too short to show both, consider showing only the prefix followed by ..., or return a standardized warning.
Implement a helper method: Encapsulate redaction logic in a shared utility to ensure consistent and secure usage throughout the codebase.
public static string RedactToken(string token, int prefixLength = 6, int suffixLength = 4)
{
if (string.IsNullOrEmpty(token))
return "[null or empty token]";
int minLengthForFullRedaction = prefixLength + suffixLength;
if (token.Length >= minLengthForFullRedaction)
{
var prefix = token.Substring(0, prefixLength);
var suffix = token.Substring(token.Length - suffixLength);
return $"{prefix}...{suffix}";
}
int minLengthForPrefixOnly = prefixLength + 3; // For "..."
if (token.Length >= minLengthForPrefixOnly)
{
var prefix = token.Substring(0, prefixLength);
return $"{prefix}...";
}
return "[token too short to redact securely]";
}Optional hashing for debugging: If correlation is needed without revealing the token, hash it using a secure algorithm (e.g., SHA256) and log only the hash.
By centralizing redaction in a reusable helper and applying consistent rules, applications can balance debugging needs with security best practices.
C#'s async/await pattern simplifies asynchronous programming, but integrating it into console applications poses a challenge. The traditional static void Main() method can't be marked as async, leading to compiler errors when attempting to use await directly.
Workaround Strategies:
Separate Async Method: Encapsulate asynchronous operations within a separate method marked as async. Then, invoke this method from Main() using .GetAwaiter().GetResult() to execute it synchronously. This approach ensures exceptions are unwrapped properly, avoiding the AggregateException that occurs with .Result or .Wait().
Async Main (C# 7.1 and Later): Starting with C# 7.1, you can define the entry point as static async Task Main(), allowing the use of await directly within Main(). This modernizes the approach and simplifies asynchronous code execution in console applications.
For a detailed explanation and code examples see Async/await in a console application.
Logging is an essential part of application development for debugging, monitoring, and understanding the flow of execution, especially in complex systems. When logging in a C# method with parameters that need validation, it's crucial to follow best practices to ensure clear and useful log messages. Below is a sample demonstrating how to log and validate parameters in a C# method:
public bool ValidateAndProcessData(string data)
{
// Log the start of the method
_logger.LogInformation("ValidateAndProcessData method started");
// Validate input data
if (string.IsNullOrEmpty(data))
{
_logger.LogError("Input data is null or empty");
throw new ArgumentException("Input data cannot be null or empty", nameof(data));
}
try
{
// Process data
_logger.LogInformation("Processing data: {data}", data);
// Simulating processing time
System.Threading.Thread.Sleep(1000);
_logger.LogInformation("Data processed successfully");
return true;
}
catch (Exception ex)
{
// Log any exceptions that occur during processing
_logger.LogError(ex, "Error processing data: {data}", data);
throw; // Re-throw the exception for higher-level handling
}
finally
{
// Log the end of the method
_logger.LogInformation("ValidateAndProcessData method completed");
}
}By following this sample, you ensure that your method logs relevant information about parameter validation and method execution, making it easier to debug and monitor your application's behavior.
In a console apps, there is often a need to obtain user input from the console while ensuring that the input is not empty or only whitespace characters.
In this sample, we define a method GetUserInput that takes an optional message parameter. It continuously prompts the user until a non-empty, non-whitespace input is provided.
static string GetUserInput(string message = "Please enter some input:")
{
string input;
do
{
Console.WriteLine(message);
input = Console.ReadLine()?.Trim();
} while (string.IsNullOrWhiteSpace(input));
return input;
}Explanation:
message parameter allows customizing input prompt message.Console.ReadLine()?.Trim() reads user input and trims leading/trailing whitespace.?. operator is used for null-conditional access, ensuring that Console.ReadLine() doesn't throw a null reference exception if the input is null.do-while loop ensures user input is not empty or whitespace.This code snippet demonstrates configuring and retrieving custom settings from appsettings.json. It defines a ClientSettings class to manage client-specific configurations such as name and URL. The appsettings.json file is structured to hold these settings under a "Clients" section. The code includes validation checks to ensure that the required settings are provided and the URL is valid.
// Configuration in appsettings.json
{
"Clients": {
"Client": {
"Name": "Acme Corporation",
"Url": "https://acme.example.com"
}
}
}
// Settings class
internal class ClientSettings
{
public const string ConfigSection = "Clients.Client";
public string ClientName { get; set; } = "DefaultClientName";
public string ClientUrl { get; set; } = string.Empty;
public static ClientSettings Load(IConfiguration configuration)
{
ClientSettings settings = configuration.GetSection(ConfigSection).Get<ClientSettings>() ?? throw new ConfigurationErrorsException($"'{ConfigSection}' section not found. Add configuration to appsettings.json");
if (string.IsNullOrWhiteSpace(settings.ClientName)) throw new ConfigurationErrorsException("ClientName is null or empty");
if (string.IsNullOrWhiteSpace(settings.ClientUrl)) throw new ConfigurationErrorsException("ClientUrl is null or empty");
if (!(Uri.TryCreate(settings.ClientUrl, UriKind.Absolute, out Uri? uri) && (uri.Scheme == Uri.UriSchemeHttp || uri.Scheme == Uri.UriSchemeHttps)))
{
throw new ConfigurationErrorsException("ClientUrl is not a valid URL");
}
return settings;
}
}
// Using setting
public Client(IConfiguration configuration)
{
_clientSettings = ClientSettings.Load(configuration);
}Links and Explanation:
Makolyte - C# How to Read Custom Configuration from appsettings.json: This link provides a detailed guide on reading custom configurations from appsettings.json in C#.
Stack Overflow - Configuration.GetSection easily gets primitive string values but not complex values: This Stack Overflow thread discusses issues related to retrieving complex values using Configuration.GetSection in .NET applications and provides insights into resolving such problems.
Automated testing in .NET is a crucial software development practice that involves using specialized tools and frameworks to create and execute tests automatically. It verifies the correctness of code, detects bugs early in the development process, and ensures that changes do not introduce new issues. .NET offers robust testing libraries like MSTest, NUnit, and xUnit, along with tools like Visual Studio Test Explorer, to simplify the creation and execution of unit, integration, and UI tests, enhancing the reliability and maintainability of .NET applications.
Basic commands
dotnet run command provides a convenient option to run your application from the source code with one command. It's useful for fast iterative development from the command lineResources
In C#, Task.Delay and Thread.Sleep are both used to introduce delays or pauses in the execution of your code, but they have different use cases and implications.
In summary, use Task.Delay when working with asynchronous code and you want to avoid blocking the current thread. Use Thread.Sleep when you explicitly want to block the current thread, but be cautious about using it in scenarios where responsiveness is important, such as in GUI applications. In modern C# applications, with the widespread use of async/await, Task.Delay is often the more appropriate choice.
Further Resources:
The Thread.Sleep Method Suspends the current thread for the specified amount of time.
Thread.Sleep is a synchronous method that blocks the current thread for the specified amount of time.Example:
void MyMethod()
{
// Do something before the delay
Thread.Sleep(1000); // Sleep for 1000 milliseconds (1 second)
// Do something after the delay
}The Task.Delay Method creates a task that will complete after a time delay.
Task.Delay is generally preferred when working with asynchronous programming using async and await.Task that represents a time delay.Example:
async Task MyMethod()
{
// Do something before the delay
await Task.Delay(1000); // Delay for 1000 milliseconds (1 second)
// Do something after the delay
}