MVC-来自Controller的推文无法正常运行

Question

I have a problem with Twitter tweet from my application, I don't understand why not working.

This is my code:

TwitterHelper.Tweet(Message, Request,
     unitOfWork.UserProfileRepository.GetByID(WebSecurity.CurrentUserId).ToString());

If I use my code from the Controller's ActionResult Index... method or from Edit method, working fine.

But If I use from my own

ActionResult SendTweet(string message) 
{
    ...

it is not working. No error message, just not reaching the twitter, don't want to authenticate, etc.

I call this method from my view with ajax

$.ajax({
    url: "/MyController/SendTweet",
    type: "POST",
    dataType: "json",
    data: { Message: $('#Message').val()},
    success: function (data) { $('#Message').text = ''; }
});

If i debug my controller I have the Message value and going through the call and no exception, but not working.

Update The Request parameter is used after the Twitter authentication. What is happening: If i call from Index for example:

if(userName != TwitterHelper._userName) 
{ 
    TwitterHelper._userName = userName; 
    TwitterHelper._accessToken = null;  
    TwitterHelper._accessTokenSecret = null; 
    TwitterHelper._userId = null; 
    TwitterHelper._screenName = null; 
}

after that:

SortedDictionary<string, string> requestTokenParams = 
    new SortedDictionary<string, string>(); 

requestTokenParams.Add("oauth_callback", HttpContext.Current.Request.Url.AbsoluteUri); 

var tokenResponse = 
    TwitterHelper.GetToken("api.twitter.com/oauth/request_token";, requestTokenParams); 

NameValueCollection qscoll = HttpUtility.ParseQueryString(tokenResponse); 

var loginUrl = "api.twitter.com/oauth/authenticate?oauth_token="; 
    + qscoll["oauth_token"];

and:

//(HERE THE BROWSER SHOWS THE TWITTER LOGIN) –
HttpContext.Current.Response.Redirect(loginUrl);   

If I call Tweet from the SendTweet method the way is the same. But here: HttpContext.Current.Response.Redirect(loginUrl); not shows anything, no login page. nothing happenin

Could you please help ? Thanks in advance.

Answer 1

You cannot Redirect from a AJAX call. (well... basically)

The line:

HttpContext.Current.Response.Redirect(loginUrl);

Is invalid because you are performing a asynchronous post.

Here is how it works:

With:

$.ajax({
    url: "/MyController/SendTweet",
    type: "POST",
    dataType: "json",
    data: { Message: $('#Message').val()},
    success: function (data) { $('#Message').text = ''; }
});

your browser is requesting a asynchronous connection with your server and is will wait for data to arrive. If this data contains a Redirect this is not really a valid instruction in this context. It just waits for data, not for instructions.

How to fix it:

Make your ActionResult SendTweet(string message) suitable for json

[HttpPost]
public JsonResult SendTweet(string message)
{
    bool isAuthenticationRequired = //detect wether a user needs to login

    if (isAuthenticationRequired)
    {
        //returns indicator that login is required
        return Json(new { result = "unauthenticated" }, JsonRequestBehavior.AllowGet);
    }

    //do normal stuff

    return Json(new { result = "tweet send!" }, JsonRequestBehavior.AllowGet);
}

Then, update your ajax call to handle the result:

$.ajax({
    url: "/MyController/SendTweet",
    type: "POST",
    dataType: "json",
    data: { Message: $('#Message').val()},
    success: function (data) { 

        if (data.result == "unauthenticated"){
            location.href = "an action which will redirect to the login page";
            return;
        }            

        $('#Message').text = ''; }
});

Maybe the location.href needs some additional parameters to re-post the data, but for now this seems sufficient.

update

I am not really familiar with the Twitter API but to redirect to the correct page you'll need a normal ActionResult , probably the one with the Ajax call on it. You can add some parameters to the url, or maybe the Twitter API provide this kind of functionality.

To redirect back to the correct page, take a look at:

requestTokenParams.Add("oauth_callback", 
      HttpContext.Current.Request.Url.AbsoluteUri);

The

HttpContext.Current.Request.Url.AbsoluteUri 

will send you to the SendTweet action again but since this is a json post action, it won't be able to find it.

You'll need to change

requestTokenParams.Add("oauth_callback", 
      HttpContext.Current.Request.Url.AbsoluteUri);

to the page with the ajax call or another page that does this and than redirect to your original page. You can also add some parameters to resend the tweet message. Something like this:

requestTokenParams.Add("oauth_callback", 
      "someactionresult?tweetmessage=" + message);

with action:

public ActionResult someactionresult (string tweetmessage)
{
    //do twitter stuff
    return RedirectToAction("your original url");
}