98 lines
4.1 KiB
C#
98 lines
4.1 KiB
C#
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// Copyright (c) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
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namespace System.Web.WebPages
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{
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/// <summary>
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/// The default BrowserOverrideStore. Gets overridden user agent for a request from a cookie.
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/// Creates a cookie to set the overridden user agent.
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/// </summary>
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public class CookieBrowserOverrideStore : BrowserOverrideStore
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{
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internal static readonly string BrowserOverrideCookieName = ".ASPXBrowserOverride";
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private readonly int _daysToExpire;
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/// <summary>
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/// Creates the BrowserOverrideStore setting any browser override cookie to expire in 7 days.
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/// </summary>
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public CookieBrowserOverrideStore()
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: this(daysToExpire: 7)
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{
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}
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/// <summary>
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/// Constructor to control the expiration of the browser override cookie.
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/// </summary>
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public CookieBrowserOverrideStore(int daysToExpire)
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{
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_daysToExpire = daysToExpire;
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}
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/// <summary>
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/// Looks for a user agent by searching for the browser override cookie. If no cookie is found
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/// returns null.
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/// </summary>
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public override string GetOverriddenUserAgent(HttpContextBase httpContext)
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{
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// Check the response to see if the cookie has been set somewhere in the current request.
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HttpCookieCollection responseCookies = httpContext.Response.Cookies;
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// NOTE: Only look for the key (via AllKeys) so a new cookie is not automatically created.
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string[] cookieNames = responseCookies.AllKeys;
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// NOTE: use a simple for loop since it performs an order of magnitude faster than .Contains()
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// and this is a hot path that gets executed for every request.
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for (int i = 0; i < cookieNames.Length; i++)
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{
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// HttpCookieCollection uses OrdinalIgnoreCase comparison for its keys
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if (String.Equals(cookieNames[i], BrowserOverrideCookieName, StringComparison.OrdinalIgnoreCase))
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{
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HttpCookie currentOverriddenBrowserCookie = responseCookies[BrowserOverrideCookieName];
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if (currentOverriddenBrowserCookie.Value != null)
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{
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return currentOverriddenBrowserCookie.Value;
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}
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else
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{
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// The cookie has no value. It was cleared on the current request so return null.
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return null;
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}
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}
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}
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// If there was no cookie found in the response check the request.
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var requestOverrideCookie = httpContext.Request.Cookies[BrowserOverrideCookieName];
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if (requestOverrideCookie != null)
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{
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return requestOverrideCookie.Value;
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}
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return null;
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}
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/// <summary>
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/// Adds a browser override cookie with the set user agent to the response of the current request.
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/// If the user agent is null the browser override cookie is set to expire, otherwise its expiration is set
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/// to daysToExpire, specified when CookieBasedOverrideStore is created.
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/// </summary>
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public override void SetOverriddenUserAgent(HttpContextBase httpContext, string userAgent)
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{
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HttpCookie browserOverrideCookie = new HttpCookie(BrowserOverrideCookieName, HttpUtility.UrlEncode(userAgent));
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if (userAgent == null)
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{
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browserOverrideCookie.Expires = DateTime.Now.AddDays(-1);
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}
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else
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{
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// Only set expiration if the cookie should live longer than the current session
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if (_daysToExpire > 0)
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{
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browserOverrideCookie.Expires = DateTime.Now.AddDays(_daysToExpire);
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}
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}
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httpContext.Response.Cookies.Remove(BrowserOverrideCookieName);
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httpContext.Response.Cookies.Add(browserOverrideCookie);
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}
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}
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}
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