rewrite/remove Facebook.Web.dll and Facebook.Web.Mvc.dll

[prabirshrestha]

rewrite/remove Facebook.Web.dll and Facebook.Web.Mvc.dll

[prabirshrestha]

I have added a new private class called FacebookWebHelper. Currently it is around 200 lines of code compared to thousand of line of Facebook.Web.dll and Facebook.Web.Mvc.dll.

Currently it is capable of parsing signed_request (both the oauth 2.0 signed_request cookie set by fb js sdk and the signed_request form value from canvas.)
There are two methods for parsing signed_request.
https://github.com/microsoft-dpe/facebook-csharp-sdk/commit/083ece31b81da663f4570c0331eb0ef696d6de50#L3R24
First method parses the signed_request string value.
https://github.com/microsoft-dpe/facebook-csharp-sdk/commit/083ece31b81da663f4570c0331eb0ef696d6de50#L3R66
Second method parses the signed_request value by looking at request.Forms["signed_request"](required by canvas app) and then request.Cookies["fbsr_appid"](required by fb js sdk). This method also caches the decoded signed_request per request, thus you will get performance benefits.

One huge advantage of FacebookWebHelper is it does not take any dependency on System.Web but rather uses Func<> so other projects like Nancy can easily consume it.

 public static object TryParseFacebookSignedRequest(string appId, string appSecret, Func<bool> isInCache, Func<object> getFromCache, Func<string> getSignedRequestFormValue, Func<string, string> getSignedRequestCookieValue, Action<object> cache, Func<string, object> deserializeObject, bool throws)

Here is an example how Nancy could make use of FacebookWebHelper. (We can easily support System.Web by using HttpContext instead of NancyContext with some other minor changes.)

    private static object TryParseFacebookSignedRequestInternal(NancyContext context, string appId, string appSecret, bool throws)
    {
        if (context == null)
            throw new ArgumentNullException("context");

        var request = context.Request;
        var items = context.Items;

        return FacebookWebHelper.TryParseFacebookSignedRequest(
            appId, appSecret,
            () => items.ContainsKey(SignedRequestKey),
            () => items[SignedRequestKey] as IDictionary<string, object>,
            () => request.Form.signed_request.HasValue ? request.Form.signed_request : string.Empty,
            cookieName => request.Cookies.ContainsKey(cookieName) ? request.Cookies[cookieName] : string.Empty,
            signedRequest => items[SignedRequestKey] = signedRequest,
            DeserializeObject,
            throws);
    }

There is also FacebookCanvasPageUrl method which is capable of generating url for facebook canvas application.
https://github.com/microsoft-dpe/facebook-csharp-sdk/commit/083ece31b81da663f4570c0331eb0ef696d6de50#L3R101

Here is a sample for FacebookCanvasPageUrl in Nancy. this can again be easily ported to System.Web.dll

    public static string FacebookCanvasPageUrl(this NancyContext context, string canvasPageOrAppName,
        bool? https = null, bool? beta = null)
    {
        if (context == null)
            throw new ArgumentNullException("context");
        if (context.Request == null)
            throw new ArgumentException("context.Request is null");

        var request = context.Request;

        return FacebookWebHelper.FacebookCanvasPageUrl(canvasPageOrAppName,
            () => request.Url.Scheme,
            () => request.Headers != null && !string.IsNullOrEmpty(request.Headers.Referrer) && new Uri(request.Headers.Referrer).Host == "apps.beta.facebook.com",
            https,
            beta);
    }

we can now call the method in the following manner: (assume I have added FacebookCanvasPageUrl as an extension method for HttpContextBase in for mvc)

 var url = HttpContext.FacebookCanvasPageUrl("appname"); // https://apps.facebook.com/appname

 // assume FacebookApplication.Current.CanvasPage = http://apps.facebook.com/appname
 url = HttpContext.FacebookCanvasePageUrl(FacebookApplication.Current); // https://apps.facebok.com/appname

 url = HttpContext.FacebookCanvasPageUrl("appname", https: false, beta: true); // http://apps.beta.facebook.com/appname

You can either pass only the appname or the full canvas page url from IFacebookApplication. You can also explicitly set https or beta. If it is null, it will look at the request and try to figure it out by itself.

Though FacebookWebHelper is small, it has huge advantage and can accomplish quite a lot.

I will be adding FacebookTabUrl() and FacebookPageUrl() in the future.

[prabirshrestha]

source is still there but the project references from the solution has been removed.

[prabirshrestha]

removing in v6.

will instead provide samples