114 lines
4.1 KiB
C#
114 lines
4.1 KiB
C#
using System.Linq;
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using System.Net;
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using Microsoft.AspNetCore.Antiforgery;
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using Microsoft.Extensions.DependencyInjection;
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namespace Microsoft.AspNetCore.Http
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{
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/// <summary>
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/// Extensions for the <see cref="HttpContext"/>.
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/// </summary>
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public static class HttpContextExtensions
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{
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// Search these additional headers for a remote client ip address.
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private static readonly string[] defaultIpHeaderNames = new[]
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{
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"X-Forwarded-For", // commonly used on all known proxies
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"X-Real-IP", // wide-spread alternative to X-Forwarded-For
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"CF-Connecting-IP" // set by Cloudflare
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};
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/// <summary>
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/// Retrieves the antiforgery token.
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/// </summary>
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/// <param name="httpContext">The current <see cref="HttpContext"/>.</param>
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/// <returns>FormName, HeaderName and Value of the antiforgery token.</returns>
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public static (string FormName, string HeaderName, string Value) GetAntiforgeryToken(this HttpContext httpContext)
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{
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var antiforgery = httpContext.RequestServices.GetService<IAntiforgery>();
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var tokenSet = antiforgery?.GetAndStoreTokens(httpContext);
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return (tokenSet?.FormFieldName, tokenSet?.HeaderName, tokenSet?.RequestToken);
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}
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/// <summary>
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/// Returns the remote ip address.
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/// </summary>
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/// <remarks>
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/// Searches for additional headers in the following order:
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/// <list type="number">
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/// <item>X-Forwarded-For</item>
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/// <item>X-Real-IP</item>
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/// <item>CF-Connecting-IP</item>
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/// </list>
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/// </remarks>
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/// <param name="httpContext">The current <see cref="HttpContext"/>.</param>
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/// <param name="ipHeaderName">The name of the header to resolve the <see cref="IPAddress"/> when behind a proxy.</param>
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/// <returns>The ip address of the client.</returns>
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public static IPAddress GetRemoteIpAddress(this HttpContext httpContext, string ipHeaderName = null)
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{
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string forwardedForAddress = null;
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var headerNames = string.IsNullOrWhiteSpace(ipHeaderName)
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? defaultIpHeaderNames
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: new[] { ipHeaderName }.Concat(defaultIpHeaderNames);
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foreach (string headerName in headerNames)
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{
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if (!httpContext.Request.Headers.ContainsKey(headerName))
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continue;
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forwardedForAddress = httpContext.Request.Headers[headerName].ToString();
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break;
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}
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if (!string.IsNullOrWhiteSpace(forwardedForAddress) && IPAddress.TryParse(forwardedForAddress, out var remoteAddress))
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return remoteAddress;
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return httpContext.Connection.RemoteIpAddress;
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}
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/// <summary>
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/// Returns whether the request was made locally.
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/// </summary>
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/// <remarks>
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/// Searches for additional headers in the following order:
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/// <list type="number">
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/// <item>X-Forwarded-For</item>
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/// <item>X-Real-IP</item>
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/// <item>CF-Connecting-IP</item>
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/// </list>
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/// </remarks>
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/// <param name="httpContext">The current <see cref="HttpContext"/>.</param>
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/// <param name="ipHeaderName">The name of the header to resolve the <see cref="IPAddress"/> when behind a proxy.</param>
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/// <returns></returns>
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public static bool IsLocalRequest(this HttpContext httpContext, string ipHeaderName = null)
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{
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var remoteIpAddress = httpContext.GetRemoteIpAddress(ipHeaderName);
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return httpContext.Connection.LocalIpAddress.Equals(remoteIpAddress);
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}
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/// <summary>
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/// Tries to retrieve the return url.
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/// </summary>
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/// <param name="httpContext">The current <see cref="HttpContext"/>.</param>
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/// <returns></returns>
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public static string GetReturnUrl(this HttpContext httpContext)
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{
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if (httpContext.Items.ContainsKey("OriginalRequest"))
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return httpContext.Items["OriginalRequest"].ToString();
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if (httpContext.Request.Query.ContainsKey("ReturnUrl"))
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return httpContext.Request.Query["ReturnUrl"].ToString();
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return null;
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}
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/// <summary>
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/// Clears a session when available.
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/// </summary>
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/// <param name="httpContext">The current <see cref="HttpContext"/>.</param>
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public static void ClearSession(this HttpContext httpContext)
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=> httpContext.Session?.Clear();
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}
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}
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