我在我的应用程序中使用ASP.NET Core Identity，我启用了外部登录（到Facebook）;我的问题是，在用户点击登录页面中的Facebook按钮后，FacebookMiddleware的角色是什么，重定向到Facebook登录页面，单击确定，然后通过Facebook重定向回到ExternalLoginCallback方法...其中是所有这个计划中的FacebookMiddleware及其功能如何？
答案 0 :(得分：0)
顾名思义，FacebookMiddleware是使用Facebook验证用户身份的组件。
当您调用UseFacebookAuthentication调用时，它基本上连接了FacebookMiddleware。
FacebookMiddleware内部使用FacebookHandler
没有比代码本身更好的解释，所以这里是FacebookHandler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());
}
}
}
答案 1 :(得分：0)
以防有人遇到同样的问题：从中间件的这段代码中抛出错误：
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，只需抛出一般错误消息。另外要知道真正的错误，你可以使用Fiddler等工具来捕获Facebook的回复，在我看来如下所示：
{＆＃34;错误＆＃34;：{＆＃34;消息＆＃34;：＆＃34;语法错误\＆＃34;字符串的预期结束而不是\＆＃34 ;; \＆＃34 ; \＆＃34;在字符5：电子邮件; first_name; last_name＆＃34;，＆＃34;键入＆＃34;：＆＃34; OAuthException＆＃34;，＆＃34; code＆＃34;：2500，＆＃34; fbtrace_id＆＃34; ：＆＃34; XXXXXXXX＆＃34;}}