/// <summary>
/// fetches Facebook user from Facebooks Graph API
/// </summary>
/// <param name="shortAccessToken">The users access token which is needed to fetch the user from Facebook</param>
/// <returns>the Facebook user</returns>
private async Task <FbUser> fetchAndStoreUserDetails(string shortAccessToken)
{
String jsonResponse = UtilService.performGetRequest(
new Uri(
"https://graph.facebook.com/v2.3/me?fields=id,email,first_name,last_name,gender,link,updated_time,verified,friends&access_token=" +
shortAccessToken));
FbUser user = JsonConvert.DeserializeObject <FbUser>(jsonResponse);
user.shortAccessToken = shortAccessToken;
await fbUserRepo.InsertAsync(user);
return(user);
}
/// <summary>
/// Checks if the users request is authenticated/authorized by proofing users access token:
/// 1. Check if user exists in the database if not fetch the user from Fracebooks Graph API.
/// 1.1. If user exists check if it is up to date (if not fetch user)
/// 2. Check if it equals the users access token in the Database.
/// 2.1. If not... inspecting access tokens (user and app access token) via Facebooks Graph API.
/// </summary>
/// <param name="shortAccessToken">The users access token which has to be validated</param>
/// <param name="userPassword">The users Facebook-Id</param>
/// <returns>true if access token is validated, otherwise false</returns>
public async Task <bool> authorizeRequest(String userFbId, String shortAccessToken)
{
FbUser user = await fbUserRepo.GetByFbIdAsync(userFbId);
//fetch user from FB if not yet in DB
if (user == null)
{
user = await fetchAndStoreUserDetails(shortAccessToken);
}
//Update Fb User when last updated time > 60 minutes
else
{
if ((DateTime.Now - user.lastUpdatedTimestamp).TotalHours > 1.00)
{
user = await fetchAndStoreUserDetails(shortAccessToken);
}
}
//When Users short access token is the same as the one in the Database then the user ist validated
if (user != null && shortAccessToken == user.shortAccessToken)
{
return(true);
}
else
{
String appAccessToken = UtilService.performGetRequest(new Uri("https://graph.facebook.com/oauth/access_token?client_id=" + fbAppId + "&client_secret=" +
fbAppSecret + "&grant_type=client_credentials"));
String jsonResponse = UtilService.performGetRequest(new Uri("https://graph.facebook.com/v2.3/debug_token?input_token=" + shortAccessToken + "&" + appAccessToken));
FbTokenInspection insp = JsonConvert.DeserializeObject <FbTokenInspection>(jsonResponse);
if (insp.data.is_valid == true)
{
if (user != null)
{
user.shortAccessToken = shortAccessToken;
fbUserRepo.UpdateAsync(user);
}
return(true);
}
else
{
return(false);
}
}
}
/**
* fetches a cities details from the google maps api and stores the updated city in the DB.
*/
private City fetchCityDetailFromGMapsAndStoreInDb(City city)
{
var urlEncodedAddress = HttpUtility.UrlEncode(city.formatted_address);
var requestUrl = "https://maps.googleapis.com/maps/api/geocode/json?address=" + urlEncodedAddress + "&key=" +
MAPS_KEY;
var result = UtilService.performGetRequest(new Uri(requestUrl));
var fetchedCities = JsonConvert.DeserializeObject <GMapsGeocodingResponse>(result);
if (fetchedCities.status == "OK")
{
var fetchedCity = fetchedCities.results[0];
fetchedCity.Id = city.Id;
var citySaveTask = cityRepo.UpdateAsync(fetchedCity);
citySaveTask.Wait();
Thread.Sleep(1000 * 2); //otherwise google maps kicks us out :-/
return(fetchedCity);
}
else
{
Thread.Sleep(1000 * 10 * 60);
return(fetchCityDetailFromGMapsAndStoreInDb(city));
}
}
