AspNetCore3.1_Middleware源码解析_3_HttpsRedirection
- 2020 年 3 月 16 日
- 笔记
概述
上文提到3.1版本默认没有使用Hsts，但是使用了这个中间件。看名字就很好理解，https跳转，顾名思义，就是跳转到
https地址。
使用场景，当用户使用http访问网站时，自动跳转到https地址。这样更加安全，不需要用户特意输入https://协议。
具体做了些我们一起来看看。
app.UseHttpsRedirection();使用方法
跟Hsts一样，HttpsRedirection默认是不需要注入的，除非你需要修改默认配置。
services.AddHttpsRedirection(config => { //https地址的端口号，默认null config.HttpsPort = 12345; //跳转响应的状态码，默认307 config.RedirectStatusCode = 302; });直接使用中间件即可
app.UseHttpsRedirection();源码解析
源代码很简单，只有两个类：HttpsRedirectionOptions配置类，HttpsRedirectionMiddleware中间件
HttpsRedirectionOptions就只有两个配置项
/// <summary> /// Options for the HttpsRedirection middleware /// </summary> public class HttpsRedirectionOptions { /// <summary> /// The status code used for the redirect response. The default is 307. /// </summary> public int RedirectStatusCode { get; set; } = StatusCodes.Status307TemporaryRedirect; /// <summary> /// The HTTPS port to be added to the redirected URL. /// </summary> /// <remarks> /// If the HttpsPort is not set, we will try to get the HttpsPort from the following: /// 1. HTTPS_PORT environment variable /// 2. IServerAddressesFeature /// If that fails then the middleware will log a warning and turn off. /// </remarks> public int? HttpsPort { get; set; } }重点看下中间件做了些什么。代码量很少，大体是这些逻辑。
- 如果请求是Https，跳过本中间件
- 中间件会依次尝试从这三个地方取端口号：HttpsRedirectionOptions的配置，HttpsRedirectionOptions，HTTPS_PORT环境变量或配置，IServerAddressesFeature(如果Webhost上绑定了https地址，本中间件能够解析出来端口号)。
- 如果没有解析出来https的端口号，则跳过本中间件。
- 如果能够解析出来https端口号，则拼接出来https地址，返回307跳转响应报文（或者配置的其他状态码）。
注：3.1同时支持HTTPS_PORT和ANCM_HTTPS_PORT这两个环境变量。
https://docs.microsoft.com/en-us/dotnet/core/compatibility/2.2-3.0
public class HttpsRedirectionMiddleware { private const int PortNotFound = -1; private readonly RequestDelegate _next; private readonly Lazy<int> _httpsPort; private readonly int _statusCode; private readonly IServerAddressesFeature _serverAddressesFeature; private readonly IConfiguration _config; private readonly ILogger _logger; /// <summary> /// Initializes the HttpsRedirectionMiddleware /// </summary> /// <param name="next"></param> /// <param name="options"></param> /// <param name="config"></param> /// <param name="loggerFactory"></param> public HttpsRedirectionMiddleware(RequestDelegate next, IOptions<HttpsRedirectionOptions> options, IConfiguration config, ILoggerFactory loggerFactory) { _next = next ?? throw new ArgumentNullException(nameof(next)); _config = config ?? throw new ArgumentNullException(nameof(config)); if (options == null) { throw new ArgumentNullException(nameof(options)); } var httpsRedirectionOptions = options.Value; if (httpsRedirectionOptions.HttpsPort.HasValue) { _httpsPort = new Lazy<int>(() => httpsRedirectionOptions.HttpsPort.Value); } else { _httpsPort = new Lazy<int>(TryGetHttpsPort); } _statusCode = httpsRedirectionOptions.RedirectStatusCode; _logger = loggerFactory.CreateLogger<HttpsRedirectionMiddleware>(); } /// <summary> /// Initializes the HttpsRedirectionMiddleware /// </summary> /// <param name="next"></param> /// <param name="options"></param> /// <param name="config"></param> /// <param name="loggerFactory"></param> /// <param name="serverAddressesFeature">The</param> public HttpsRedirectionMiddleware(RequestDelegate next, IOptions<HttpsRedirectionOptions> options, IConfiguration config, ILoggerFactory loggerFactory, IServerAddressesFeature serverAddressesFeature) : this(next, options, config, loggerFactory) { _serverAddressesFeature = serverAddressesFeature ?? throw new ArgumentNullException(nameof(serverAddressesFeature)); } /// <summary> /// Invokes the HttpsRedirectionMiddleware /// </summary> /// <param name="context"></param> /// <returns></returns> public Task Invoke(HttpContext context) { if (context.Request.IsHttps) { return _next(context); } var port = _httpsPort.Value; if (port == PortNotFound) { return _next(context); } var host = context.Request.Host; if (port != 443) { host = new HostString(host.Host, port); } else { host = new HostString(host.Host); } var request = context.Request; var redirectUrl = UriHelper.BuildAbsolute( "https", host, request.PathBase, request.Path, request.QueryString); context.Response.StatusCode = _statusCode; context.Response.Headers[HeaderNames.Location] = redirectUrl; _logger.RedirectingToHttps(redirectUrl); return Task.CompletedTask; } // Returns PortNotFound (-1) if we were unable to determine the port. private int TryGetHttpsPort() { // The IServerAddressesFeature will not be ready until the middleware is Invoked, // Order for finding the HTTPS port: // 1. Set in the HttpsRedirectionOptions // 2. HTTPS_PORT environment variable // 3. IServerAddressesFeature // 4. Fail if not sets var nullablePort = _config.GetValue<int?>("HTTPS_PORT") ?? _config.GetValue<int?>("ANCM_HTTPS_PORT"); if (nullablePort.HasValue) { var port = nullablePort.Value; _logger.PortLoadedFromConfig(port); return port; } if (_serverAddressesFeature == null) { _logger.FailedToDeterminePort(); return PortNotFound; } foreach (var address in _serverAddressesFeature.Addresses) { var bindingAddress = BindingAddress.Parse(address); if (bindingAddress.Scheme.Equals("https", StringComparison.OrdinalIgnoreCase)) { // If we find multiple different https ports specified, throw if (nullablePort.HasValue && nullablePort != bindingAddress.Port) { _logger.FailedMultiplePorts(); return PortNotFound; } else { nullablePort = bindingAddress.Port; } } } if (nullablePort.HasValue) { var port = nullablePort.Value; _logger.PortFromServer(port); return port; } _logger.FailedToDeterminePort(); return PortNotFound; } }OK，完成了。
