Develop Reference

Instasharp in a Console Application

I have a .net console application that I want to use to pull Instagram posts via the Instasharp wrapper using a hashtag search.
I use C# .net web forms extensively and am not very familiar with MVC nor how to use the await keyword. The code sample below seems to run, but never provides any output.
This line:
var tagInfo = await tagApi.Get("soccer");
Returns me to the calling method with no indication of retrieved data.
Can anyone provide insights as to what I am doing wrong here?
public static async void GetInstagram(String tag, InstagramConfig config)
{
var instagramPosts = await LoadInstagramPosts(tag, config);
dynamic dyn = JsonConvert.DeserializeObject(instagramPosts.ToString());
foreach (var data in dyn.data)
{
Console.WriteLine("{0} - {1}", data.filter, data.images.standard_resolution.url);
}
}
public static async Task<TagResponse> LoadInstagramPosts(String hashTagTerm, InstagramConfig config)
{
var tagApi = new InstaSharp.Endpoints.Tags(config);
var tagInfo = await tagApi.Get("soccer");
}
EDITED code after first comment which solved my initial problem.
I feel like I'm close but something is still missing.
See specific questions below...
I've based the code on the documentation from InstaSharp GitHub (https://github.com/InstaSharp/InstaSharp). GitHubs example is based on an MVC application, mine is not an MVC project, but a console application.
I feel like I am very close and maybe others will benefit from helping me solve this.
My specific questions...
1) Not sure where the 'code' parameter in the OAuth method originate??
2) How to perform the needed call backs with Instagram??
var config = new InstaSharp.InstagramConfig(location.InstagramClientId, location.InstagramClientSecret, "http://localhost");
string instagramLoginLink = InstagramLogin(config);
GetInstagram("soccer", config, instagramLoginLink);
public static async void GetInstagram(String tag, InstagramConfig config, string code)
{
OAuthResponse oAuthResponse = await OAuth(code, config);
var instagramPosts = await LoadInstagramPosts(tag, config, oAuthResponse);
if(instagramPosts.Data != null)
{
dynamic dyn = JsonConvert.DeserializeObject(instagramPosts.Data.ToString());
foreach (var data in dyn.data)
{
Console.WriteLine("{0} - {1}", data.filter, data.images.standard_resolution.url);
}
}
}
public static string InstagramLogin(InstagramConfig config)
{
var scopes = new List<OAuth.Scope>();
scopes.Add(InstaSharp.OAuth.Scope.Likes);
scopes.Add(InstaSharp.OAuth.Scope.Comments);
string link = InstaSharp.OAuth.AuthLink(config.OAuthUri + "authorize", config.ClientId, config.RedirectUri, scopes, InstaSharp.OAuth.ResponseType.Code);
return link;
}
public static async Task<OAuthResponse> OAuth(string code, InstagramConfig config)
{
// add this code to the auth object
var auth = new OAuth(config);
// now we have to call back to instagram and include the code they gave us
// along with our client secret
return await auth.RequestToken(code);
}
public static async Task<TagResponse> LoadInstagramPosts(String hashTagTerm, InstagramConfig config, OAuthResponse OAuth)
{
var tagApi = new InstaSharp.Endpoints.Tags(config, OAuth);
return await tagApi.Get("soccer");
}

I'm a bit late to the show, yet probably my answer will help someone who find this question when googling, someone like me.
The main problem with your approach is that Instagram is using OAuth authentication. I suggest you to google on OAuth to understand the principles, but I will try to explain the practical points of it below.
OAuth approach means that the result of the InstagramLogin method in the snippet above is not the code. It's the link where you need to send you user (yes, using a browser or a web-view) so that they can sign into their Instagram account and then authorize your application to access their data (so-called user consent screen).
In the end, after user consent, Instagram will redirect browser to the URL of your choice (it should be previously added in the list of allowed redirect urls in Instagram API -> Manage Clients (top-right corner) -> Create/Select client to Manage -> Security tab)
You can try set a breakpoint and copy the value of instagramLoginLink into your browser's address box. You will be able to see the whole flow of authentication and consent - and finally the redirect url that will most probably produce 404 in your browser.
This final link will contain the code in a get parameter. It's the so-called grant code that allows you to get an access token. This code is to be extracted from url and then used in your call to OAuth.RequestToken).
PS: Yes, everything I say above means that you need either a web app running that will redirect user to Instagram or a client-side app that will show the user a web view and somehow handle the moment when Instagram sends the user back to your redirect url - to grab the code and proceed.

OAuth Refresh Token does not deserialize / invalid_grant

I have followed the wonderful tutorial by Taiser Joudah for implementing refresh tokens with Asp.Net Web Api 2 and Owin. It all went so well...except I can't get it to work. :-) It all "seems" like it works up until the point I request a refresh token. Then all I get back is:
“error”: “invalid_grant”
and no description to go with. One of the comments on that post had the same symptom and the response was to generate a MachineKey for the web.config. I tried this but it didn't help. And I'm thinking that maybe only applies when the Auth and Resource server are not the same anyway, which in this case they are.
The bottom line is using PostMan I can make the request for the refresh token and in ReceiveAsync the context.Ticket deserialization does not work. After the call to “context.DeserializeTicket(refreshToken.ProtectedTicket);” the context.Ticket is still null. Curiously if I manually deserialize the ProtectedTicket using the Acccess Token’s AccessTokenFormat it will deserialize properly. But it does not work using the Refresh Token's RefreshTokenFormat object:
var thisWorks = Startup.OAuthOptions.AccessTokenFormat.Unprotect(refreshToken.ProtectedTicket);
var thisDoesnt = Startup.OAuthOptions.RefreshTokenFormat.Unprotect(refreshToken.ProtectedTicket);
It sure seems like a config problem…but I’ve racked my brains and compared a lot of samples. What could be causing this?
EDIT
Oops...meant to link to the tutorial article: http://bitoftech.net/2014/07/16/enable-oauth-refresh-tokens-angularjs-app-using-asp-net-web-api-2-owin/

I think your problem is the order you create the refresh_token with CreateAsync.
Make sure you follow order bellow:
context.Ticket.Properties.IssuedUtc = refreshTokenProperties.IssuedUtc;
context.Ticket.Properties.ExpiresUtc = refreshTokenProperties.ExpiresUtc;
context.SetToken(context.SerializeTicket());
Then you can persist the token into DB. But have in mind that it is not necessary to persist. You can DeserializeTicket from context.Token in ReceiveAsync:
public async Task ReceiveAsync(AuthenticationTokenReceiveContext context)
{
context.DeserializeTicket(context.Token);
if (context.Ticket != null)
{
context.SetTicket(context.Ticket);
}
}
Hope this help!

Following the same tutorial, I had the same problem, this worked for me
public async Task CreateAsync(AuthenticationTokenCreateContext context)
{
//...
context.Ticket.Properties.AllowRefresh = true;
token.ProtectedTicket = context.SerializeTicket();
//...
}

Using Facebook API to access public group event data

I'm developing a public website and what I want to do is pretty straightforward, but I'm pulling my hair out trying to get everything working right.
I administer an open Facebook group and I want to display the public facebook events of this group on my website.
I can't seem to figure out how to setup my authentication so that I can access the event data. Here is my code for using my application to get an auth token:
var fb = new FacebookClientWrapper();
dynamic result = fb.Get("oauth/access_token", new
{
client_id = AppSettings.AppID,
client_secret = AppSettings.AppSecret,
grant_type = "client_credentials"
});
fb.AccessToken = result.access_token;
I know this works fine because I can access some information - for example, if I access a specific event by its ID, I can retrieve that information.
The problem occurs when I try to retrieve a list of events with fields within a date range:
[HttpGet]
public object GetEventDetails(string unixStartDateTime, string unixEndDateTime)
{
var parms = new Dictionary<string, object>();
parms.Add("fields", new[] { "id","name","description","start_time","venue" });
if (!String.IsNullOrEmpty(unixStartDateTime)) { parms.Add("since", unixStartDateTime); }
if (!String.IsNullOrEmpty(unixEndDateTime)) { parms.Add("until", unixEndDateTime); }
var eventsLink = String.Format(#"/{0}/events", AppSettings.GroupID);
return ObjectFactory.GetInstance<IFacebookClient>().Get(eventsLink,parms);
}
(I'm aware that even if this did succeed, the return value wouldn't be serializable - I'm not concerned about that quite yet).
This GET request returns the following message:
(OAuthException - #102) A user access token is required to request this resource.
So the message is quite clear: I need a user access token to get the data I've requested. The question is - what is the best way to do this? Can I give my application a certain permission to read this data? I've looked over all the permissions available to apps, but I don't see one that would do the trick.
I don't want to require people to log onto Facebook to look at public event data, and I love the idea of allowing people with no technical experience to essentially update the website content by posting Facebook events to the group. Right now, I have to duplicate anything they do.
I would think this kind of application would be very common, but no matter what I've read or tried, I can't quite find an example of the same thing that works.

From the docs at https://developers.facebook.com/docs/graph-api/reference/v2.0/group/events you need
A user access token for a member of the group with user_groups permission.
To avoid the hassle, you could create such an Access Token via the Graph Explorer and then store it in your application. Remember to exchange that Access Token to a long-lived one (https://developers.facebook.com/docs/facebook-login/access-tokens/#extending), and that you have to renew the Access Token every 60 days afterwards.

Validating Google ID tokens in C#

I need to validate a Google ID token passed from a mobile device at my ASP.NET web api.
Google have some sample code here but it relies on a JWT NuGet package which is .Net 4.5 only (I am using C#/.Net 4.0). Is anyone aware of any samples which do this without these packages or has achieved this themselves? The use of the package makes it very difficult to work out what I need to do without it.

According to this github issue, you can now use GoogleJsonWebSignature.ValidateAsync method to validate a Google-signed JWT. Simply pass the idToken string to the method.
var validPayload = await GoogleJsonWebSignature.ValidateAsync(idToken);
Assert.NotNull(validPayload);
If it is not a valid one, it will return null.
Note that to use this method, you need to install Google.Apis.Auth nuget firsthand.

The challenge is validating the JWT certificate in the ID token. There is currently not a library I'm aware of that can do this that doesn't require .Net 4.5 and until there is a solution for JWT validation in .NET 4.0, there will not be an easy solution.
However, if you have an access token, you can look into performing validation using oauth2.tokeninfo. To perform basic validation using token info, you can do something like the following:
// Use Tokeninfo to validate the user and the client.
var tokeninfo_request = new Oauth2Service().Tokeninfo();
tokeninfo_request.Access_token = _authState.AccessToken;
var tokeninfo = tokeninfo_request.Fetch();
if (userid == tokeninfo.User_id
&& tokeninfo.Issued_to == CLIENT_ID)
{
// Basic validation succeeded
}
else
{
// The credentials did not match.
}
The information returned from the Google OAuth2 API tells you more information about a particular token such as the client id it was issued too as well as its expiration time.
Note You should not be passing around the access token but instead should be doing this check after exchanging a one-time code to retrieve an access token.

ClientId also needs to be passed, which should be set from Google API Console. If only pass TokenId, GoogleJsonWebSignature throws error. This answer is in addition to #edmundpie answer
var settings = new GoogleJsonWebSignature.ValidationSettings()
{
Audience = new List<string>() { "[Placeholder for Client Id].apps.googleusercontent.com" }
};
var validPayload = await GoogleJsonWebSignature.ValidateAsync(model.ExternalTokenId, settings);

IAuthenticationResponse.GetExtension<ClaimsResponse>() always returning null

Update
Thanks to a comment by #IvanL, it turns out that the problem is Google specific. I have since tried other providers and for those everything works as expected. Google just doesn't seem to send claims information. Haven't yet been able to figure out why or what I need to differently to get Google to send it.
A wild stab in the dark says it may be related to the realm being defaulted to http://:/ as I have seen an answer by Andrew Arnott that Google changes the claimed identifier for the same account based on the realm passed with the authentication request.
Another possibly important tidbit of information: unlike many of the examples that can be found around the web for using dotnetopenauth, I am not using a "simple" textbox and composing the openIdIdentifier myself, but I am using the openID selector and that is providing the openIdIdentifier passed to the ValidateAtOpenIdProvider. (As per the Adding OpenID authentication to your ASP.NET MVC 4 application article.)
Question is: why is IAuthenticationResponse.GetExtension() always returning null when using Google as the openId provider, when otherwise all relevant gotcha's with regard to Google (Email requested as required, AXFetchAsSregTransform, etc) have been addressed?
Original
I am struggling with getting DotNetOpenAuth to parse the response returned from the provider. Followed the instructions of Adding OpenID authentication to your ASP.NET MVC 4 application up to the point where the login should be working and a login result in a return to the home page with the user's name (nick name) displayed at the top right. (That is up to "The user should at this point see the following:" just over half way down the article).
I am using Visual Studio Web Developer 2010 Express with C#. DotNetOpenAuth version is 4.0.3.12153 (according to the packages.config, 4.0.3.12163 according to Windows Explorer).
My web.config was modified following the instructions in Activating AXFetchAsSregTransform which was the solution for DotNetOpenId - Open Id get some data
Unfortunately it wasn't enough to get it working for me.
The openid-selector is working fine and resulting in a correct selection of the openid provider. The authentication request is created as follows:
public IAuthenticationRequest ValidateAtOpenIdProvider(string openIdIdentifier)
{
IAuthenticationRequest openIdRequest = openId.CreateRequest(Identifier.Parse(openIdIdentifier));
var fields = new ClaimsRequest()
{
Email = DemandLevel.Require,
FullName = DemandLevel.Require,
Nickname = DemandLevel.Require
};
openIdRequest.AddExtension(fields);
return openIdRequest;
}
This all works. I can login and authorize the page to receive my information, which then results in a call to GetUser:
public OpenIdUser GetUser()
{
OpenIdUser user = null;
IAuthenticationResponse openIdResponse = openId.GetResponse();
if (openIdResponse.IsSuccessful())
{
user = ResponseIntoUser(openIdResponse);
}
return user;
}
openIdResponse.IsSuccessful is implemented as an extension method (see linked article):
return response != null && response.Status == AuthenticationStatus.Authenticated;
and always is successful as the ResponseIntoUser method is entered:
private OpenIdUser ResponseIntoUser(IAuthenticationResponse response)
{
OpenIdUser user = null;
var claimResponseUntrusted = response.GetUntrustedExtension<ClaimsResponse>();
var claimResponse = response.GetExtension<ClaimsResponse>();
// For this to work with the newer/est version of DotNetOpenAuth, make sure web.config
// file contains required settings. See link for more details.
// http://www.dotnetopenauth.net/developers/help/the-axfetchassregtransform-behavior/
if (claimResponse != null)
{
user = new OpenIdUser(claimResponse, response.ClaimedIdentifier);
}
else if (claimResponseUntrusted != null)
{
user = new OpenIdUser(claimResponseUntrusted, response.ClaimedIdentifier);
}
else
{
user = new OpenIdUser("ikke#gmail.com;ikke van ikkenstein;ikke nick;ikkeclaimedid");
}
return user;
}
My version above only differs from the code in the linked article by my addition of the final else block to ensure that I always get the home page with a user name and a logoff link displayed (which helps when trying to do this several times in succession).
I have tried both Google and Yahoo. Both authenticate fine, both return an identity assertion as logged by the WebDev server. However, GetUntrustedExtenstion and GetExtension always return null. I always get to see "ikke nick" from the last else, never the name I actually used to authenticate.
I am at a loss on how to continue to try and get this to work. It probably is some oversight on my part (I am an experienced developer but just started dipping my toes in C# and web front-end development), and I can't see it.
Any and all suggestions on how to proceed / debug this are very much welcome.

Are you using Google as OpenId provider to test your solution against? Because Google has/had the habit of including the Claims only the first time you authenticate the application. So perhaps try using a fresh google account and see if that works?
Sorry for the slow response, doing a big migration at a client this week :-) Glad that this little comment resolved your issue.