Facebookmiddleware在外部登录中的作用是什么?

Question

我在应用程序中使用ASP.NET核心身份，在该应用程序中，我在其中启用了外部登录（到Facebook）;我的问题是用户单击页面登录中的Facebook按钮，重定向到Facebook登录页面，单击"确定"，然后通过Facebook重定向到Facebook，然后通过Facebook重定向到externalloginCallback方法...在哪里...Facebookmiddleware在所有这些方案中及其有什么作用？

Answer 1

顾名思义，Facebookmiddleware是使用Facebook对用户进行认证的组件。

当您调用UsefaceBookAuthentication调用时，它基本上会添加Facebookmiddleware。

Facebookmiddleware在内部使用FacebookHandler

没有什么比代码本身更好的解释了，所以这是Facebook Handler的代码

 internal class FacebookHandler : OAuthHandler<FacebookOptions>
        {
            public FacebookHandler(HttpClient httpClient) : base(httpClient)
            {
            }
            protected override async Task<AuthenticationTicket>   CreateTicketAsync(ClaimsIdentity identity, AuthenticationProperties properties, OAuthTokenResponse tokens)
            {
                string text = QueryHelpers.AddQueryString(this.get_Options().get_UserInformationEndpoint(), "access_token", tokens.get_AccessToken());
                if (this.get_Options().SendAppSecretProof)
                {
                    text = QueryHelpers.AddQueryString(text, "appsecret_proof", this.GenerateAppSecretProof(tokens.get_AccessToken()));
                }
                if (this.get_Options().Fields.get_Count() > 0)
                {
                    text = QueryHelpers.AddQueryString(text, "fields", string.Join(",", this.get_Options().Fields));
                }
                HttpResponseMessage httpResponseMessage = await this.get_Backchannel().GetAsync(text, this.get_Context().get_RequestAborted());
                if (!httpResponseMessage.get_IsSuccessStatusCode())
                {
                    throw new HttpRequestException(string.Format("Failed to retrieve Facebook user information ({0}) Please check if the authentication information is correct and the corresponding Facebook Graph API is enabled.", httpResponseMessage.get_StatusCode()));
                }
                JObject jObject = JObject.Parse(await httpResponseMessage.get_Content().ReadAsStringAsync());
                AuthenticationTicket authenticationTicket = new AuthenticationTicket(new ClaimsPrincipal(identity), properties, this.get_Options().get_AuthenticationScheme());
                OAuthCreatingTicketContext oAuthCreatingTicketContext = new OAuthCreatingTicketContext(authenticationTicket, this.get_Context(), this.get_Options(), this.get_Backchannel(), tokens, jObject);
                string id = FacebookHelper.GetId(jObject);
                if (!string.IsNullOrEmpty(id))
                {
                    identity.AddClaim(new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/nameidentifier", id, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
                }
                string ageRangeMin = FacebookHelper.GetAgeRangeMin(jObject);
                if (!string.IsNullOrEmpty(ageRangeMin))
                {
                    identity.AddClaim(new  Claim("urn:facebook:age_range_min", ageRangeMin, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
                }
                string ageRangeMax = FacebookHelper.GetAgeRangeMax(jObject);
                if (!string.IsNullOrEmpty(ageRangeMax))
                {
                    identity.AddClaim(new Claim("urn:facebook:age_range_max", ageRangeMax, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
                }
                string birthday = FacebookHelper.GetBirthday(jObject);
                if (!string.IsNullOrEmpty(birthday))
                {
                    identity.AddClaim(new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/dateofbirth", birthday, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
                }
                string email = FacebookHelper.GetEmail(jObject);
            if (!string.IsNullOrEmpty(email))
            {
                identity.AddClaim(new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/emailaddress", email, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
            }
            string firstName = FacebookHelper.GetFirstName(jObject);
            if (!string.IsNullOrEmpty(firstName))
            {
                identity.AddClaim(new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/givenname", firstName, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
            }
            string gender = FacebookHelper.GetGender(jObject);
            if (!string.IsNullOrEmpty(gender))
            {
                identity.AddClaim(new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/gender", gender, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
            }
            string lastName = FacebookHelper.GetLastName(jObject);
            if (!string.IsNullOrEmpty(lastName))
            {
                identity.AddClaim(new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/surname", lastName, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
            }
            string link = FacebookHelper.GetLink(jObject);
            if (!string.IsNullOrEmpty(link))
            {
                identity.AddClaim(new Claim("urn:facebook:link", link, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
            }
            string location = FacebookHelper.GetLocation(jObject);
            if (!string.IsNullOrEmpty(location))
            {
                identity.AddClaim(new Claim("urn:facebook:location", location, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
            }
            string locale = FacebookHelper.GetLocale(jObject);
            if (!string.IsNullOrEmpty(locale))
            {
                identity.AddClaim(new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/locality", locale, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
            }
            string middleName = FacebookHelper.GetMiddleName(jObject);
            if (!string.IsNullOrEmpty(middleName))
            {
                identity.AddClaim(new Claim("urn:facebook:middle_name", middleName, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
            }
            string name = FacebookHelper.GetName(jObject);
            if (!string.IsNullOrEmpty(name))
            {
                identity.AddClaim(new Claim("http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name", name, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
            }
            string timeZone = FacebookHelper.GetTimeZone(jObject);
            if (!string.IsNullOrEmpty(timeZone))
            {
                identity.AddClaim(new Claim("urn:facebook:timezone", timeZone, "http://www.w3.org/2001/XMLSchema#string", this.get_Options().get_ClaimsIssuer()));
            }
            await this.get_Options().get_Events().CreatingTicket(oAuthCreatingTicketContext);
            return oAuthCreatingTicketContext.get_Ticket();
        }
        private string GenerateAppSecretProof(string accessToken)
        {
            string result;
            using (HMACSHA256 hMACSHA = new HMACSHA256(Encoding.get_ASCII().GetBytes(base.get_Options().AppSecret)))
            {
                byte[] array = hMACSHA.ComputeHash(Encoding.get_ASCII().GetBytes(accessToken));
                StringBuilder stringBuilder = new StringBuilder();
                for (int i = 0; i < array.Length; i++)
                {
                    stringBuilder.Append(array[i].ToString("x2", CultureInfo.get_InvariantCulture()));
                }
                result = stringBuilder.ToString();
            }
            return result;
        }
        protected override string FormatScope()
        {
            return string.Join(",", base.get_Options().get_Scope());
        }
    }
}

Answer 2

以防万一某人遇到相同的问题：错误是从中间件中从此代码中丢弃的：

var response = Backchannel.GetAsync(endpoint).Result; if (!response.IsSuccessStatusCode) { throw new HttpRequestException($"Failed to retrieve Facebook user information ({response.StatusCode}) Please check if the authentication information is correct and the corresponding Facebook Graph API is enabled."); }

简而言之，开发人员决定，如果状态代码不是成功的代码，则只需发出通用错误消息即可。在其他情况下，要知道真正的错误是，您可以使用Fiddler之类的工具从Facebook捕获响应，在我的情况下，这看起来如下：

{" error"：{" message"："语法错误"字符串的预期末端而不是 "。，"代码"：2500，" fbtrace_id"：" xxxxxxxx"}}