Welcome!

Microsoft Cloud Authors: Lori MacVittie, Elizabeth White, Yeshim Deniz, Serafima Al, Janakiram MSV

Related Topics: Microsoft Cloud, Mobile IoT

Microsoft Cloud: Blog Feed Post

What Do You Call One Search Result From StackOverflow?

Windows Phone 7 301 Redirect Bug

Microsoft Session at Cloud Expo

I checked with the Windows Phone 7 team before putting this post out, and got the OK to write about it.  I hit this bug when building out my FriendLinks Windows Phone 7 application, and was surprised to find it was a bona fide bug and not a problem with my coding skills.  If there was a default value in the constructor for any new project I start, it would look something like:

codingErrorResponsibilty == this.programmerName;

In any event, here’s the cruxt of the bug.  If you are using HttpWebRequest developing on Windows Phone 7, and you get a 301 redirect returned from the web server, and that web server sets a cookie, the current build (as of 03/16/10 at Mix10) of Windows Phone 7 will throw an exception.

In the case of my applications, I was trying to determine the title of the page as defined by the “<title></title>” tags for a given URL.  The function I wrote for this was:

try
{
    WebResponse response = ((HttpWebRequest)result.AsyncState)
                            .EndGetResponse(result);
    StreamReader reader = new StreamReader(response.GetResponseStream());
    string responseString = reader.ReadToEnd();
    string regex = @"(?<=<title.*>)([\s\S]*)(?=</title>)";

    if (new List<string>(response.Headers.AllKeys).Contains("Content-Type"))
    {
        if (response.Headers["Content-Type"].StartsWith("text/html"))
        {
            Regex ex = new Regex(regex, RegexOptions.IgnoreCase);

            selectedUrlTitle = ex.Match(responseString).Value.Trim();

            if (String.IsNullOrEmpty(selectedUrlTitle))
            {
                selectedUrlTitle = "No title for page";
            }
        }

    }
    
    UrlTitleRequestCompleted(this, EventArgs.Empty);
}

For some URLs this was throwing the most elusive of all exceptions: CookieException.  Behold, I present to you a StackOverflowWhack! [note: a nod to GoogleWhacks]  There should really be a better name for that.

image

There is only one response for this search query at StackOverflow.  Interestingly enough, when I first hit this bug, there were no questions – this one was asked in the last week.

The debug information from Visual Studio was even less useful.  It was telling me that the cookie was too big.  A little searching revealed that this exception is thrown when you try to set a cookie larger than MaxCookieSize for a CookieContainer.  That value cannot be changed in Silverlight, and since I don’t control the remote web servers, I can’t control the cookie coming back.  Worse, whether or not the cookie was being set on the 301 redirects varied from domain to domain.  Some set it, some didn’t.

In using Fiddler2 to debug this problem, here is what a redirect looks like that won’t throw the CookieException:

HTTP/1.1 301 Moved Permanently
Proxy-Connection: Keep-Alive
Connection: Keep-Alive
Transfer-Encoding: chunked
Via: 1.1 RED-PRXY-21
Date: Wed, 03 Mar 2010 02:55:15 GMT
Location: http://blogs.bnet.com/career-advice/?p=101
Content-Type: text/html; charset=UTF-8
Server: Apache
Set-Cookie: supr=supr301; path=/; domain=.su.pr
Vary: Accept-Encoding

In this case, su.pr didn’t try to set the cookie.  And here is a 301 redirect that tries to set a cookie:

HTTP/1.1 301 Moved
Proxy-Connection: Keep-Alive
Connection: Keep-Alive
Content-Length: 381
Via: 1.1 RED-PRXY-21
Date: Wed, 03 Mar 2010 02:57:15 GMT
Location: http://www.allfacebook.com/2010/03/facebook-developers-see-
               dramatic-drop-in-traffic-following-removal-of-notifications/
Content-Type: text/html; charset=utf-8
Server: nginx/0.7.42
Set-Cookie: _bit=4b8dd00b-0013c-01992-b5a08fa8;domain=.bit.ly;
                expires=Sun Aug 29 22:57:15 2010;path=/; HttpOnly
MIME-Version: 1.0

In this case, bit.ly is in fact trying to set a cookie.  What helped lead me down the path of figuring this out was a short.to link that forwarded to a bit.ly link.  Here’s the chain of raw headers:

HTTP/1.1 301 Moved Permanently
Proxy-Connection: Keep-Alive
Connection: Keep-Alive
Content-Length: 0
Via: 1.1 RED-PRXY-21
Expires: Fri, 01 Jan 1990 00:00:00 GMT
Date: Wed, 03 Mar 2010 02:58:43 GMT
Location: http://bit.ly/8ZyVoz
Content-Type: text/html; charset=utf-8
Server: Google Frontend
Cache-Control: no-cache
X-XSS-Protection: 0

HTTP/1.1 301 Moved
Proxy-Connection: Keep-Alive
Connection: Keep-Alive
Content-Length: 312
Via: 1.1 RED-PRXY-21
Date: Wed, 03 Mar 2010 02:58:44 GMT
Location: http://news.cnet.com/8301-13578_3-10462563-38.html
Content-Type: text/html; charset=utf-8
Server: nginx/0.7.42
Set-Cookie: _bit=4b8dd064-000f6-0198d-b5a08fa8;domain=.bit.ly;
                expires=Sun Aug 29 22:58:44 2010;path=/; HttpOnly
MIME-Version: 1.0

As you can see here, the first header revealed a 301 to a bit.ly URL, which then tried to redirect to a news.com article.  Some other offenders of this cookie setting on 301 redirects are FourSquare and TechCrunch.  Mind you, this isn’t a bug in their 301 redirect, it’s a bug in how Windows Phone 7 handles the redirect.

I ultimately had to abandon this path to get the page title because once that CookieException is thrown, there is no data in the exception that allows you to get access to the header.  The exception is thrown when the WebResponse object is being set to the result of reading to the end of the asynch response.  The CookieException itself doesn’t reveal any of the 301 redirect information, so recovering from this exception is next to impossible, except to abandon trying to get the URL title.

For my specific app, I needed to get that title information, and since the vast majority of links coming through Twitter were bit.ly, I needed another way.  Mercifully, TechMeme reveals this information through their API.

So there you go – if you are getting a 301 redirect in a HttpWebRequest, and your code is throwing a CookieException, now you know why.  This is a filed bug and should be fixed, but given the amount of excitement around Windows Phone 7 development right now, I wanted to try and save people pain and suffering.  It’s better that only one of us lose hair.

Read the original blog entry...

More Stories By Brandon Watson

Brandon Watson is Director for Windows Phone 7. He specifically focuses on developers and the developer platform. He rejoined Microsoft in 2008 after nearly a decade on Wall Street and running successful start-ups. He has both an engineering degree and an economics degree from the University of Pennsylvania, as well as an MBA from The Wharton School of Business, and blogs at www.manyniches.com.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
Business professionals no longer wonder if they'll migrate to the cloud; it's now a matter of when. The cloud environment has proved to be a major force in transitioning to an agile business model that enables quick decisions and fast implementation that solidify customer relationships. And when the cloud is combined with the power of cognitive computing, it drives innovation and transformation that achieves astounding competitive advantage.
The Founder of NostaLab and a member of the Google Health Advisory Board, John is a unique combination of strategic thinker, marketer and entrepreneur. His career was built on the "science of advertising" combining strategy, creativity and marketing for industry-leading results. Combined with his ability to communicate complicated scientific concepts in a way that consumers and scientists alike can appreciate, John is a sought-after speaker for conferences on the forefront of healthcare science,...
Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at Cloud Expo, Ed Featherston, a director and senior enterprise architect at Collaborative Consulting, discussed the key considerations around quality, volume, timeliness, and pedigree that must be dealt with in order to properly fuel that engine.
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at @ThingsExpo, James Kirkland, Red Hat's Chief Archi...
The current age of digital transformation means that IT organizations must adapt their toolset to cover all digital experiences, beyond just the end users’. Today’s businesses can no longer focus solely on the digital interactions they manage with employees or customers; they must now contend with non-traditional factors. Whether it's the power of brand to make or break a company, the need to monitor across all locations 24/7, or the ability to proactively resolve issues, companies must adapt to...
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settl...
Organizations planning enterprise data center consolidation and modernization projects are faced with a challenging, costly reality. Requirements to deploy modern, cloud-native applications simultaneously with traditional client/server applications are almost impossible to achieve with hardware-centric enterprise infrastructure. Compute and network infrastructure are fast moving down a software-defined path, but storage has been a laggard. Until now.
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
DXWorldEXPO LLC announced today that the upcoming DXWorldEXPO | CloudEXPO New York event will feature 10 companies from Poland to participate at the "Poland Digital Transformation Pavilion" on November 12-13, 2018.
Digital Transformation is much more than a buzzword. The radical shift to digital mechanisms for almost every process is evident across all industries and verticals. This is often especially true in financial services, where the legacy environment is many times unable to keep up with the rapidly shifting demands of the consumer. The constant pressure to provide complete, omnichannel delivery of customer-facing solutions to meet both regulatory and customer demands is putting enormous pressure on...
The best way to leverage your CloudEXPO | DXWorldEXPO presence as a sponsor and exhibitor is to plan your news announcements around our events. The press covering CloudEXPO | DXWorldEXPO will have access to these releases and will amplify your news announcements. More than two dozen Cloud companies either set deals at our shows or have announced their mergers and acquisitions at CloudEXPO. Product announcements during our show provide your company with the most reach through our targeted audienc...
JETRO showcased Japan Digital Transformation Pavilion at SYS-CON's 21st International Cloud Expo® at the Santa Clara Convention Center in Santa Clara, CA. The Japan External Trade Organization (JETRO) is a non-profit organization that provides business support services to companies expanding to Japan. With the support of JETRO's dedicated staff, clients can incorporate their business; receive visa, immigration, and HR support; find dedicated office space; identify local government subsidies; get...
DXWorldEXPO LLC announced today that All in Mobile, a mobile app development company from Poland, will exhibit at the 22nd International CloudEXPO | DXWorldEXPO. All In Mobile is a mobile app development company from Poland. Since 2014, they maintain passion for developing mobile applications for enterprises and startups worldwide.
@DevOpsSummit at Cloud Expo, taking place November 12-13 in New York City, NY, is co-located with 22nd international CloudEXPO | first international DXWorldEXPO and will feature technical sessions from a rock star conference faculty and the leading industry players in the world.
"Akvelon is a software development company and we also provide consultancy services to folks who are looking to scale or accelerate their engineering roadmaps," explained Jeremiah Mothersell, Marketing Manager at Akvelon, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
As data explodes in quantity, importance and from new sources, the need for managing and protecting data residing across physical, virtual, and cloud environments grow with it. Managing data includes protecting it, indexing and classifying it for true, long-term management, compliance and E-Discovery. Commvault can ensure this with a single pane of glass solution – whether in a private cloud, a Service Provider delivered public cloud or a hybrid cloud environment – across the heterogeneous enter...
DXWorldEXPO LLC announced today that ICC-USA, a computer systems integrator and server manufacturing company focused on developing products and product appliances, will exhibit at the 22nd International CloudEXPO | DXWorldEXPO. DXWordEXPO New York 2018, colocated with CloudEXPO New York 2018 will be held November 11-13, 2018, in New York City. ICC is a computer systems integrator and server manufacturing company focused on developing products and product appliances to meet a wide range of ...
More and more brands have jumped on the IoT bandwagon. We have an excess of wearables – activity trackers, smartwatches, smart glasses and sneakers, and more that track seemingly endless datapoints. However, most consumers have no idea what “IoT” means. Creating more wearables that track data shouldn't be the aim of brands; delivering meaningful, tangible relevance to their users should be. We're in a period in which the IoT pendulum is still swinging. Initially, it swung toward "smart for smart...
Headquartered in Plainsboro, NJ, Synametrics Technologies has provided IT professionals and computer systems developers since 1997. Based on the success of their initial product offerings (WinSQL and DeltaCopy), the company continues to create and hone innovative products that help its customers get more from their computer applications, databases and infrastructure. To date, over one million users around the world have chosen Synametrics solutions to help power their accelerated business or per...
Dion Hinchcliffe is an internationally recognized digital expert, bestselling book author, frequent keynote speaker, analyst, futurist, and transformation expert based in Washington, DC. He is currently Chief Strategy Officer at the industry-leading digital strategy and online community solutions firm, 7Summits.