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How to solve this error The remote server returned an error: (401) Unauthorized using Dropbox developer API

I have configure dropbox developer API in c#. and pass token and secretkey in below method.
OAuthToken oauth = new OAuthToken(DropboxAccessToken,DropboxAccessSecretKey);
var api = new DropboxApi(ConsumerKey, ConsumerSecret, oauth);'''
var account = api.GetAccountInfo();
Last statement raise "The remote server returned an error: (401) Unauthorized" this error.
Please help me how to solve this and please let me know if any missing condition or steps.

Based on the code you shared, it looks like you're trying to use OAuth 1 with Dropbox API v1. (OAuth 1 uses separate access token key and secrets parts, whereas OAuth 2 uses a single bearer access token. Also, the GetAccountInfo method name indicates Dropbox API v1.)
Dropbox API v1, along with the use of OAuth 1 with it, are retired now. You should instead use Dropbox API v2 with OAuth 2. For .NET, we recommend using the official Dropbox API v2 .NET SDK. It includes instructions for getting started, full documentation, and example apps.

How to implement OAuth 2.0 in ASMX (web-reference)?

I am very new in implementing OAuth 2.0. I have implemented web-reference (ASMX file) in my xamarin project. Now I need to implement OAuth 2.0 for authentication. But I am not sure if ASMX supports OAuth2.0 or not. Do I need to implement WCF instead of Web refernce(ASMX) or is it possible in web reference (ASMX) to implement the OAuth2.0?

One possible solution is to add the token aquired from the authority to the Authorization header.
Your code could look similar to this:
var redirectURI = Windows.Security.Authentication.Web.WebAuthenticationBroker.GetCurrentApplicationCallbackUri();
var _authContext = new AuthenticationContext(authority);
var tokenResult = await _authContext.AcquireTokenAsync(serviceResourceId, clientId, redirectURI);
if (tokenResult.Status != AuthenticationStatus.Success)
{
//Not authenticated
return;
}
var svc = new YourServiceReference.YourClient();
using (var scope = new OperationContextScope(svc.InnerChannel))
{
var httpRequestProperty = new HttpRequestMessageProperty();
httpRequestProperty.Headers[System.Net.HttpRequestHeader.Authorization] = tokenResult.AccessToken;
OperationContext.Current.OutgoingMessageProperties[HttpRequestMessageProperty.Name] = httpRequestProperty;
var result = svc.MyFunction();
//Do something with the data
}

Tricky - this is how mobile OAuth solutions work - but it is a big job:
Your Xamarin app would need to implement Mobile SSO to sign users in
Users of your Xamarin app would be redirected to login via an Authorization Server / Identity Provider after which they will receive an OAuth access token
After login your Xamarin App would then be able to call an API with the token and act on behalf of the user to get data
The API would need to validate received access tokens
SOLUTION PARTS
API: ASMX is an old technology so if you are working on the Microsoft stack you would use something newer such as a .Net Core Web API
MOBILE APP: The harder part of the solution will be implementing Mobile SSO, if you have not done so already.
How much of this solution exists already?

How to get access token from httpcontext using owin and Mvc 5

I've got a IDP implemented in IdentityServer 4. My web app client(implemented in Mvc 5) authenticates with the IDP but now I need to get the access token from the request.
A way to do that in .Net Core is to use the Microsoft.AspNetCore.Authentication.AuthenticationTokenExtensions like so:
HttpContext.Authentication.GetTokenAsync("acccess_token")
I would like to be able to do the same in my .net Mvc5 web app client but I can't find any nuget package or namespace that has a similar implementation. It is important to be able to do this in MVC5 and not .net Core. Anyone came across this before?
PS- Also worth to mention that I'm using OpenIdConnect

The recently released 4.1.0 version of Katana now supports the SaveTokens property (backported from ASP.NET Core).
In order to get the access token:
Update the Microsoft.Owin.Security.OpenIdConnect package to 4.1.0 (or newer)
Configure SaveTokens in your Startup class:
app.UseOpenIdConnectAuthentication(new OpenIdConnectAuthenticationOptions
{
// Other options removed for readability
SaveTokens = true,
// Required for the authorization code flow to exchange for tokens automatically
RedeemCode = true
});
Read the access token in your Controller:
var result = await Request.GetOwinContext().Authentication.AuthenticateAsync("Cookies");
string token = result.Properties.Dictionary["access_token"];

In your controller you can get the token using this code:
var token = ActionContext.Request.Headers.Authorization.Parameter;

I spent some type before I understood, we need to send a string as an argument of AuthenticateAsync which is used in AuthenticationType and SignInAsAuthenticationType.
I hilly recond to use CookieAuthenticationDefaults.AuthenticationType because it will save you from typos.

How do I setup a valid on-premise ADFS URI?

I have a .NET 4.6.2 Windows client application which needs to get an authentication token from our on-premise ADFS server and use it to call an ASP.NET Core REST API. It's client name, id (GUID) and re-direct URI have been registered with ADFS. I am using the latest ADAL (v3.13) library to facilitate the authentication. I am attempting to get a token as demonstrated in the ADAL sample code like this:
AuthenticationContext authenticationContext = new AuthenticationContext("https://<adfs-sts-server>/<rest-api-host>", false);
var result = authenticationContext.AcquireTokenAsync(<rest-api-resource-uri>, clientId, redirectUri, new PlatformParameters(PromptBehavior.Auto));
The AcquireTokenAsync call returns an error, saying: The browser based authentication dialog failed to complete. Reason: The server has not found anything matching the requested URI (Uniform Resource Identifier).
Can anyone tell me:
Is the "requested URI" refered to in the error the https://<adfs-sts-server>/<rest-api-host> or <rest-api-resource-uri>?
Do I need to register <rest-api-host> or <rest-api-resource-uri> with ADFS in some way, and if so how?
Any other information I need to get this to work?
Thanks!
Peter

Using Active Directory Federation Services (ADFS) to provide authentication for on-premise endpoints from a Windows Client
Configuring ADFS
There are 2 parts to configuring ADFS.
Register the client application with ADFS
ADFS needs to be able to identify the application requesting user authentication, whether it be a service, WPF application, Web client or Office Add-in. I have gone generic and added the following client, which we can use for most of our C# requests; we may need to register a new client with different callback for Web clients.
Use one of the many tools out there to generate a GUID for the client ID.
* CLIENT_ID and APP_NAME should be unique.
* For a web client the redirect URI is where the auth service will redirect your call after authenticating the user. It should be an endpoint where you can process the token and continue with your client application. The redirect URI is not really used with rich clients/services/add-ins.
CLIENT_ID = 26E54EC9-7988-4DAE-A527-483A8A78B1C6
APP_NAME = Investplus
DESCRIPTION = Invest+ rich client suite
REDIRECT_URI = https://server/redirect-adfs.html
Instructions for Client registration
(may be possible in a wizard, but this is what I found on the web and it worked fo us)
Log on to the AD FS server as administrator and open a Windows PowerShell command window.
Enter the following command. In Windows PowerShell
Add-AdfsClient -ClientId <CLIENT_ID> -Name <APP_NAME> -RedirectUri <REDIRECT_URI>
Register the resource to be accessed ('Relying Party' in ADFS speak)
I found this link useful, it takes you through the steps of the wizard for setting up a relying party.
Instructions for Relying Party registration
The administrator on the server team will need to use the ADFS Add Relying Party Trust Wizard, and under the "Select Data Source" step select Enter data about the relying party manually.
Values you need to supply for this wizard:
DISPLAY_NAME = "MyInvestApi" (Unique display name for this Relying party)
PROFILE = "AD FS Profile"
ENABLE_SUPPORT_FOR_WS-FEDERATION_PASSIVE_PROTOCOL = true
URL = "https://server/api" (Unique URL for this RP)
ADD_ONE_OR_MORE_IDENTIFIERS = eg. "urn:myInvestApi" and "https://server/api"
ACCEPT_REMAINING_DEFAULTS
when given the opportunity, Add Claim Rules:
SEND_LDAP_ATTRIBUTES_AS_CLAIMS = true
ATTRIBUTE_STORE = Active Directory
SELECT_USEFUL_ATTRIBUTES = User-Principal-Name; Email; Display-Name
Configuring/Coding the Client application
Microsoft provides Active Directory Authentication Libraries (ADAL) for a range of platforms and languages from C# to Javascript, and from iOS to Cordova to Node.
The API exposed has changed significantly in each major version: I am using the latest C# library, currently 3.13.5.
The library makes the coding very simple, just a few lines; where I had problems was:
I couldn't find an explanation of what URL to use for the ADFS
Secure Token Service (STS)
I couldn't find documentation of the whole process as I am doing here (most documentation focussed on Azure FS), I struggled to work out
how the values provided to ADFS for Client and Relying party mapped
to the values used in the code.
What is the ADFS endpoint/URL to use in code?
Microsoft's best practice is to name your ADFS/STS server URL https://sts.domain.com (some people use https://adfs.domain.com, ask your server admins). However, if you try to hit this from a browser you'll get a 404 - Not found and trying to retrieve a token in the code, the ADAL library reports:
The browser based authentication dialog failed to complete. Reason: The server has not found anything matching the requested URI (Uniform Resource Identifier).
This is how I found the endpoint to use:
ADFS pubishes federation metadata at 'https://sts.domain.com/federationmetadata/2007-06/federationmetadata.xml'
Extract this file and open in a text editor.
When configuring the Relying Party, we specified "Enable Support for WS-Federation Passive Protocol" when specifying our resource endpoint, so search the XML for PassiveRequestorEndpoint.
Use the <Address> from this node - in my case https://sts.domain.com/adfs/ls/. I don't know if this will always be the value, or if it is specified when ADFS is setup and therefore potentially different per site.
What other values to use in the code?
We want our client app to retrieve a JSON Web Token (JWT) from ADFS which we can pass to our protected resource for authentication/authorization purposes.
At its most simple, the access token can be retrieved in 3 lines of code + configuration, and this will show how to translate what we have configured in ADFS to the values required by ADAL:
var stsEndpoint = "https://sts.domain.com/adfs/ls/";
var relyingPartyIdentifier = "urn:myInvestApi"; // Tenant in Azure AD speak, but this is an on-premise service
var authority = stsEndpoint + relyingPartyIdentifier;
var restResourceUrl = "https://server/api";
var redirectUri = "https://server/redirect-adfs.html";
const string CLIENT_ID = "26E54EC9-7988-4DAE-A527-483A8A78B1C6";
AuthenticationContext authenticationContext = new AuthenticationContext(authority, false);
var asyncRequest = authenticationContext.AcquireTokenAsync(restResourceUrl, CLIENT_ID, redirectUri, new PlatformParameters(PromptBehavior.Auto));
var accessToken = asyncRequest.Result.AccessToken;
Useful references
ASP.NET Core Token Authentication Guide
ADAL - Native App to REST service - Authentication with ACS via Browser Dialog
Create a line-of-business Azure app with AD FS authentication
OAuth 2 Simplified

To issue the token for the web API, we need to make the ADFS to aware it by creating a relying party trust for the web API. And when we add a replying party we need to specify the identifiers for the replying party like figure below(Windows Server 2012 R2):
Then we can use this identifiers as the resource URI to acquire the token for this replying party. Please ensure that the resource URI is correct as you config like figure above.
And here is an article about developing with ADFS using OAuth:
Developing Modern Applications using OAuth and Active Directory Federation Services

Depending on the version of asdf, you may be able to use 'discovery' to obtain the endpoints to use.
Have a look at this post for more details: http://www.cloudidentity.com/blog/2015/08/21/openid-connect-web-sign-on-with-adfs-in-windows-server-2016-tp3/

How to get Google Analytics data using OAuth?

Hy guys, we are developing a system which will provide users with access to Google Analytics. I'm trying to implement it in the way so user don't need to enter their Google login credentials on our site, so trying to get it work using their login.
I have a solution which gets analytics using user's email and password. I'm looking for a solution which will not require user's email and password but can not find anything.
How can it be done? any advices or links will be appreciated.
thanks

Ok, guys, after a few days of struggle I finally figured this out. There is no documentation on the Internet and people who had done it before did not want to share their success by some reason. I found this discussion which helped me.
To make it work you will need DotNetOpenAuth from http://www.dotnetopenauth.net/ and gdata from http://code.google.com/p/google-gdata/
so
using DotNetOpenAuth.ApplicationBlock;
using DotNetOpenAuth.OAuth;
using Google.GData.Client;
using Google.GData.Analytics;
In DotNetOpenAuth there is sample project named OAuthConsumer which you need.
Change it to requiest authorization for Analytics:
GoogleConsumer.RequestAuthorization(google, GoogleConsumer.Applications.Analytics);
This will get you Token and Token secret.
You can use them like this:
GOAuthRequestFactory requestFactory = new GOAuthRequestFactory("cp", TokenManager.ConsumerKey); //ConsumerKey actually is the name of web application
requestFactory.ConsumerKey = TokenManager.ConsumerKey;
requestFactory.ConsumerSecret = TokenManager.ConsumerSecret;
requestFactory.Token = AccessToken;
requestFactory.TokenSecret = TokenManager.GetTokenSecret(AccessToken);
requestFactory.UseSSL = true;
AnalyticsService service = new AnalyticsService(requestFactory.ApplicationName); // acually the same as ConsumerKey
service.RequestFactory = requestFactory;
const string dataFeedUrl = "https://www.google.com/analytics/feeds/data";
DataQuery query1 = new DataQuery(dataFeedUrl);
This service you can use like here or here
And the last thing, you WILL NOT be available to try and test it on localhost so you will need a domain which MUST be registered with Google here in order to get consumer key and secret

There's a .NET/C# class for Google Data authentication that can be used to access the Google Analytics Data Export API (since the API is part of the Google Data standard, though you might need to make Google Analytics specific adjustments.)*
The authentication is best managed by creating a Google Registered Application, as this allows you to make the authentication without security warnings (and, for that matter, security lapses).
There are three forms of supported authentication; the 'secure'/passwordless ones are OAuth and AuthSub (which is the Google-proprietary version of OAuth); the hardcoded username and password version is referred to by Google as 'ClientLogin', and is not considered secure or ideal for multiple-user applications.
*(Since you tagged the question .netc#)
Edit: More details on using AuthSub or OAuth with the .NET library:
AuthSubSupport: http://code.google.com/p/google-gdata/wiki/AuthSubSupport
Code Samples on how to use the libraries for OAuth authentication: http://code.google.com/apis/gdata/docs/auth/oauth.html#2LeggedOAuth (Click the .NET tab).

Basics of working with OAuth are here: http://code.google.com/apis/accounts/docs/OpenID.html#working
Authenticating with OAuth: http://code.google.com/apis/accounts/docs/OAuth.html
After you authenticate a user with OAuth, you will have the request token that works like the one you get back from Google's login API. From there, it should be the same as username/password.

I don't think you need to mess with OAuth.
The google analytics api lets you pass credentials. Just start from this data feed example.
http://code.google.com/p/google-gdata/source/browse/trunk/clients/cs/samples/Analytics_DataFeed_Sample/dataFeed.cs
// Configure GA API and do client login Authorization.
AnalyticsService asv = new AnalyticsService("gaExportAPI_acctSample_v2.0");
asv.setUserCredentials(clientUser, clientPass);
Download the client library here
http://code.google.com/apis/analytics/docs/gdata/gdataLibraries.html
To get a feel for data queries, play with this and then copy the values into the example above
http://code.google.com/apis/analytics/docs/gdata/gdataExplorer.html