HttpClientToCurlLogger 1.2.2

HttpClientToCurlLogger

A lightweight .NET library that automatically logs all HttpClient requests as cURL commands. Perfect for debugging, testing, and sharing API requests during development.

Features

Automatic Logging - Captures all HttpClient requests automatically
cURL Format - Generates ready-to-use cURL commands
Easy Integration - Single line of configuration
Toggle On/Off - Enable or disable logging via configuration
Multiple Clients - Works with all registered HttpClient instances
Headers & Body - Includes headers and request body in the cURL output
.NET Standard 2.0 - Compatible with .NET Core 2.0+ and .NET Framework 4.6.1+

Installation

Install via NuGet Package Manager:

dotnet add package HttpClientToCurlLogger

Or via Package Manager Console:

Install-Package HttpClientToCurlLogger

Usage

Basic Setup

Add the following to your Startup.cs or Program.cs:

using HttpClientToCurlLogger;

public void ConfigureServices(IServiceCollection services)
{
    // Add cURL logging
    services.AddCurlLogging(options =>
    {
        options.EnableLogging = true; // Set to false to disable
    });

    // Register your HttpClient(s)
    services.AddHttpClient("MyClient");
    services.AddHttpClient<IMyService, MyService>();
}

ASP.NET Core Minimal API (.NET 6+)

using HttpClientToCurlLogger;

var builder = WebApplication.CreateBuilder(args);

// Add cURL logging
builder.Services.AddCurlLogging(options =>
{
    options.EnableLogging = true;
});

// Register HttpClient
builder.Services.AddHttpClient("MyClient");

var app = builder.Build();
app.Run();

Example Output

When you make an HTTP request:

var client = httpClientFactory.CreateClient("MyClient");
await client.PostAsJsonAsync("https://api.example.com/users", new { name = "John" });

You'll see in your logs:

curl -X POST -H "Content-Type: application/json; charset=utf-8" -d "{\"name\":\"John\"}" "https://api.example.com/users"

You can copy this cURL command directly to your terminal or Postman!

The output will look like this:

================================================================================
cURL Command (copy-paste ready):
================================================================================
curl -X POST \
  -H "ApiKey: your-api-key" \
  -H "Content-Type: application/json; charset=utf-8" \
  -d "{\"name\":\"John\"}" \
  "https://api.example.com/users"
================================================================================

Configuration Options

Advanced Configuration

services.AddCurlLogging(options =>
{
    options.EnableLogging = true;
    options.UseMultiLineFormat = true;   // Multi-line format with \ continuation
    options.UseFormattedOutput = true;   // With separators and headers
    options.UseConsoleOutput = false;    // Use ILogger (default)
});

For Structured Logging (Serilog, NLog with JSON formatters):

If you're using structured logging that outputs JSON (like Serilog with JSON formatter or Elastic.CommonSchema.Serilog), enable UseConsoleOutput to bypass the logger and write directly to console for readable output:

services.AddCurlLogging(options =>
{
    options.EnableLogging = true;
    options.UseMultiLineFormat = true;   // Multi-line format
    options.UseFormattedOutput = true;   // With separators
    options.UseConsoleOutput = true;     // Direct console output (bypasses structured logging)
});

For compact single-line output (useful for simple logging):

services.AddCurlLogging(options =>
{
    options.EnableLogging = true;
    options.UseMultiLineFormat = false;  // Single line
    options.UseFormattedOutput = false;  // No separators
});

Environment-Based Configuration

You can control logging based on environment:

services.AddCurlLogging(options =>
{
    options.EnableLogging = builder.Environment.IsDevelopment();
});

Or use configuration files (appsettings.json):

{
  "CurlLogging": {
    "EnableLogging": true,
    "UseMultiLineFormat": true,
    "UseFormattedOutput": true,
    "UseConsoleOutput": true
  }
}

services.AddCurlLogging(options =>
{
    configuration.GetSection("CurlLogging").Bind(options);
});

How It Works

The library uses an IHttpMessageHandlerBuilderFilter to automatically inject a DelegatingHandler into all registered HttpClient instances. This handler intercepts requests and logs them as cURL commands using the configured logger (typically ILogger<T>).

Requirements

• .NET Standard 2.0 or higher
• Microsoft.Extensions.Http 2.1.0+
• Microsoft.Extensions.Logging.Abstractions 2.1.0+

Supported Frameworks

• .NET Core 2.0+
• .NET 5, 6, 7, 8+
• .NET Framework 4.6.1+

Use Cases

• Debugging - Quickly see what requests your application is making
• Testing - Copy cURL commands to test APIs manually
• Documentation - Share API request examples with your team
• Troubleshooting - Diagnose integration issues with external APIs

Best Practices

1. Disable in Production - Only enable logging in development/staging environments
2. Sensitive Data - Be aware that headers and body content are logged (including auth tokens)
3. Performance - Minimal overhead, but consider disabling for high-throughput scenarios

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Author

Reza Ghasemi

Repository

https://github.com/vamcan/HttpClientToCurlLogger