/// <summary>
/// Creates a ClientContext token for the incoming WebAPI request. This is done by
/// - looking up the servicesToken
/// - extracting the cacheKey
/// - get the AccessToken from cache. If the AccessToken is expired a new one is requested using the refresh token
/// - creation of a ClientContext object based on the AccessToken
/// </summary>
/// <param name="httpControllerContext">Information about the HTTP request that reached the WebAPI controller</param>
/// <returns>A valid ClientContext object</returns>
public static ClientContext GetClientContext(HttpControllerContext httpControllerContext)
{
if (httpControllerContext == null)
{
throw new ArgumentNullException("httpControllerContext");
}
string cacheKey = GetCacheKeyValue(httpControllerContext);
if (!String.IsNullOrEmpty(cacheKey))
{
WebAPIContexCacheItem cacheItem = WebAPIContextCache.Instance.Get(cacheKey);
//request a new access token from ACS whenever our current access token will expire in less than 1 hour
if (cacheItem.AccessToken.ExpiresOn < (DateTime.Now.AddHours(-1)))
{
Uri targetUri = new Uri(cacheItem.SharePointServiceContext.HostWebUrl);
OAuth2AccessTokenResponse accessToken = TokenHelper.GetAccessToken(cacheItem.RefreshToken, TokenHelper.SharePointPrincipal, targetUri.Authority, TokenHelper.GetRealmFromTargetUrl(targetUri));
cacheItem.AccessToken = accessToken;
//update the cache
WebAPIContextCache.Instance.Put(cacheKey, cacheItem);
Log.Info(CoreResources.Services_TokenRefreshed, cacheKey, cacheItem.SharePointServiceContext.HostWebUrl);
}
return(TokenHelper.GetClientContextWithAccessToken(cacheItem.SharePointServiceContext.HostWebUrl, cacheItem.AccessToken.AccessToken));
}
else
{
Log.Warning(Constants.LOGGING_SOURCE, CoreResources.Services_CookieWithCachKeyNotFound);
throw new Exception("The cookie with the cachekey was not found...nothing can be retrieved from cache, so no clientcontext can be created.");
}
}
/// <summary>
/// This method needs to be called from a code behind of the SharePoint app startup page (default.aspx). It registers the calling
/// SharePoint app by calling a specific "Register" api in your WebAPI service.
///
/// Note:
/// Given that method is async you'll need to add the Async="true" page directive to the page that uses this method.
/// </summary>
/// <param name="page">The page object, needed to insert the services token cookie and read the querystring</param>
/// <param name="apiRequest">Route to the "Register" API</param>
/// <param name="serviceEndPoint">Optional Uri to the WebAPI service endpoint. If null then the assumption is taken that the WebAPI is hosted together with the page making this call</param>
public static async void RegisterWebAPIService(this Page page, string apiRequest, Uri serviceEndPoint = null)
{
if (page == null)
{
throw new ArgumentNullException("page");
}
if (string.IsNullOrEmpty(apiRequest))
{
throw new ArgumentNullException("apiRequest");
}
if (!page.IsPostBack)
{
if (page.Request.QueryString.AsString(SERVICES_TOKEN, string.Empty).Equals(string.Empty))
{
// Construct a JsonWebSecurityToken so we can fetch the cachekey...implementation is copied from tokenhelper approach
string cacheKey = string.Empty;
string contextToken = TokenHelper.GetContextTokenFromRequest(page.Request);
JsonWebSecurityTokenHandler tokenHandler = TokenHelper.CreateJsonWebSecurityTokenHandler();
SecurityToken securityToken = tokenHandler.ReadToken(contextToken);
JsonWebSecurityToken jsonToken = securityToken as JsonWebSecurityToken;
string appctx = GetClaimValue(jsonToken, "appctx");
if (appctx != null)
{
ClientContext ctx = new ClientContext("http://tempuri.org");
Dictionary <string, object> dict = (Dictionary <string, object>)ctx.ParseObjectFromJsonString(appctx);
cacheKey = (string)dict["CacheKey"];
}
// Remove special chars (=, +, /, {}) from cachekey as there's a flaw in CookieHeaderValue when the
// cookie is read. This flaw replaces special chars with a space.
cacheKey = RemoveSpecialCharacters(cacheKey);
bool httpOnly = true;
if (serviceEndPoint != null)
{
if (!serviceEndPoint.Host.Equals(page.Request.Url.Host, StringComparison.InvariantCultureIgnoreCase))
{
httpOnly = false;
}
}
else
{
serviceEndPoint = new Uri(String.Format("{0}://{1}:{2}", page.Request.Url.Scheme, page.Request.Url.Host, page.Request.Url.Port));
}
// Write the cachekey in a cookie
HttpCookie cookie = new HttpCookie(SERVICES_TOKEN)
{
Value = cacheKey,
Secure = true,
HttpOnly = httpOnly,
};
page.Response.AppendCookie(cookie);
//Register the ClientContext
WebAPIContext sharePointServiceContext = new WebAPIContext()
{
CacheKey = cacheKey,
ClientId = TokenHelper.ClientId,
ClientSecret = TokenHelper.ClientSecret,
Token = contextToken,
HostWebUrl = page.Request.QueryString.AsString("SPHostUrl", null),
AppWebUrl = page.Request.QueryString.AsString("SPAppWebUrl", null),
HostedAppHostName = String.Format("{0}:{1}", page.Request.Url.Host, page.Request.Url.Port),
};
using (var client = new HttpClient())
{
client.BaseAddress = serviceEndPoint;
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response = await client.PutAsJsonAsync(apiRequest, sharePointServiceContext);
if (!response.IsSuccessStatusCode)
{
Log.Error(CoreResources.Service_RegistrationFailed, apiRequest, serviceEndPoint.ToString(), cacheKey);
throw new Exception(String.Format("Service registration failed: {0}", response.StatusCode));
}
Log.Info(CoreResources.Services_Registered, apiRequest, serviceEndPoint.ToString(), cacheKey);
}
}
}
}
