Edi.AspNetCore.Utils 2.0.0

Edi.AspNetCore.Utils

Common ASP.NET Core helper classes for my own projects. Targets .NET 10.

Installation

dotnet add package Edi.AspNetCore.Utils

Features

ClientIPHelper

Returns the client IP address from HttpContext.Connection.RemoteIpAddress. Configure ASP.NET Core Forwarded Headers Middleware before calling this helper when the application runs behind a proxy. Raw forwarding headers are not read directly because clients can spoof them.

string ip = ClientIPHelper.GetClientIP(httpContext);

IPAddressHelper

Classifies ordinary public Internet IPv4 and IPv6 addresses. Private, loopback, link-local, documentation, reserved, multicast, transition, tunneling, and other special-use addresses return false. IPv4-mapped IPv6 addresses are normalized before classification.

bool publicIPv4 = IPAddressHelper.IsPublicIPAddress("8.8.8.8");       // true
bool privateIPv4 = IPAddressHelper.IsPublicIPAddress("192.168.1.1"); // false
bool loopbackIPv6 = IPAddressHelper.IsPublicIPAddress("::1");        // false

Public HTTP client safety

AddPublicHttpClientSafety registers reusable DNS validation and HTTP connection services for applications that must fetch user-controlled public URLs.

builder.Services.AddPublicHttpClientSafety();

builder.Services.AddHttpClient<MyPublicUrlClient>()
    .ConfigurePrimaryHttpMessageHandler(serviceProvider =>
        serviceProvider.GetRequiredService<PublicHttpMessageHandlerFactory>().Create());

Use IPublicHttpUrlValidator.IsPublicHttpUrlAsync before business processing. The handler performs the authoritative check immediately before connecting and binds the socket to a checked address. It rejects hosts with any non-public DNS result and disables redirects, cookies, and proxy use. Applications must validate every redirect location before issuing the next request.

SmartXFFHeaderExtensions

Middleware extension that configures ForwardedHeaders from appsettings.json.

app.UseSmartXFFHeader();

Configuration (appsettings.json):

{
  "ForwardedHeaders": {
    "HeaderName": "X-Forwarded-For",
    "KnownProxies": [ "203.0.113.1", "203.0.113.2" ]
  }
}

• HeaderName — custom forwarded-for header name (optional, max 40 chars, must be a valid HTTP header name).
• KnownProxies — list of trusted proxy IP addresses. When empty or entirely invalid, ASP.NET Core's default loopback-only trusted proxies are retained. A valid explicit list replaces those defaults. Trust behavior does not change automatically in containers.

VersionHelper

Reads version information from the entry assembly.

string version = VersionHelper.AppVersion;
bool isPreview = VersionHelper.IsNonStableVersion();
string os = VersionHelper.TryGetFullOSVersion();

EnvironmentHelper

Runtime environment detection and tag parsing.

bool onAzure  = EnvironmentHelper.IsRunningOnAzureAppService(); // checks WEBSITE_SITE_NAME
bool inDocker = EnvironmentHelper.IsRunningInDocker();          // checks DOTNET_RUNNING_IN_CONTAINER

// Reads comma-separated tags from APP_TAGS (or a custom env var)
// Valid characters: a-z A-Z 0-9 - # @ $ ( ) [ ] /
IEnumerable<string> tags = EnvironmentHelper.GetEnvironmentTags();
IEnumerable<string> tags = EnvironmentHelper.GetEnvironmentTags("CUSTOM_TAGS");

SecurityHelper

URL sanitization and password hashing utilities.

SterilizeLink

Sanitizes links by allowing local absolute paths and HTTP/HTTPS links. Literal IP hosts must be ordinary public Internet addresses. This method does not resolve DNS names and is not a replacement for the public HTTP client safety services when the server makes an outbound request.

string safe = SecurityHelper.SterilizeLink(rawUrl);

HashPassword / GenerateSalt

PBKDF2 password hashing via Microsoft.AspNetCore.Cryptography.KeyDerivation.

string salt = SecurityHelper.GenerateSalt();           // 16 random bytes, Base64
string hash = SecurityHelper.HashPassword(password, salt);

Parameters for HashPassword: prf (default HMACSHA256), iterationCount (default 100000), numBytesRequested (default 32).

UrlExtension

Extension methods on string and Uri.

// Validate URL scheme
bool valid  = url.IsValidUrl();                        // HTTP or HTTPS
bool secure = url.IsValidUrl(UrlScheme.Https);

// Combine base URL with a path segment
string full = "https://example.com".CombineUrl("api/v1");
// → "https://example.com/api/v1"

// Detect localhost
bool local = new Uri("http://localhost:5000").IsLocalhostUrl();

DomainDataHelper

Typed wrapper around AppDomain.CurrentDomain data storage.

DomainDataHelper.SetAppDomainData("MyKey", myValue);
string value = DomainDataHelper.GetAppDomainData<string>("MyKey", defaultValue: "fallback");

ProblemDetailsResultFilter

MVC result filter that converts any non-ProblemDetails 4xx/5xx ObjectResult into RFC 7807/9457 Problem Details format, including a traceId extension.

builder.Services.AddControllers(options =>
{
    options.Filters.Add<ProblemDetailsResultFilter>();
});

Controllers can continue returning semantic helpers and still produce consistent error responses:

return NotFound("Resource not found.");  // → ProblemDetails with status 404

ProblemDetailsStatusCodePages

A StatusCodePages handler that writes RFC 7807 Problem Details for responses with no body (e.g. 404 from middleware).

app.UseStatusCodePages(ProblemDetailsStatusCodePages.Handler);

License

MIT