Getting Started with Node.js and Mango (Sockets)

July 6th, 2011 No comments

It’s been a while since I’ve found time to blog – but it’s not like I’ve left you in cold hands. Rohan has been doing a great job posting on the Silverlight for Windows Phone Performance blog (check it out if you haven’t yet).

On a completely non-performance related topic (we’ll get to those in the next couple of blog posts), I’ve been meaning to play around with Node.js for a while, and when a colleague posed a question about using it with Mango, I thought it might be a great excuse to polish off the Beta 2 tools (get them while they’re hot!) and do some Socketing!

First things first – grab 7zip (if you don’t have it already), and Node.js binaries for Windows (or build it yourself). Extract these to a convenient location and you should be good to go.

We’re going to use the Hello World sample ripped straight from the Node.js homepage, with one extra debugging addition (highlighted in yellow) and a practical change (highlighted in green – see “gotcha!” below):

var http = require('http');
http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
 console.log('Sent message'); }).listen(1337, "192.168.2.125");
console.log('Server running at http://192.168.2.125:1337/');


Gotcha Warning!

A common mistake at this point is to stick with the sample’s use of 127.0.0.1 (locahost). This will work great from your browser, but not from the emulator or your device (regardless of whether it is connected to WiFi or tethered via Zune). This is because the emulator and the device join the network as *new* devices which means they get a newly assigned IP address and they act just as though they were a machine on the network. This leads to 127.0.0.1 pointing back to themselves, which is not allowed, leaving you with a “NetworkDown” network error. Instead, make sure to set your IP to your local LAN address (usually starts with 192.168.X.X or 10.X.X.X). You can find your exact IP address from cmd by typing “ipconfig” and looking for the address that corresponds to your local network.

Testing the Server

Now, save your modified script somewhere somewhere convenient (I saved it to c:\nodejs\bin\servers\helloworld.js) and then launch the server with a simple:

C:\nodejs\bin>node servers/helloworld.js
Server running at http://192.168.2.125:1337/

Note the use of UNIX style paths… If you see any errors at this point it’s most likely path related. Fix your path so it is relative to your binary and you should be good to go. Need to verify that everything is working? Fire up your browser and enter http://localhost:1337 and you should see “Hello World!”.

Note: When launching the server you may get the Windows warning dialog about a program accessing the network, feel free to set the settings to whatever you are comfortable with, just note that Node.js will need at least local network access so that you can talk to it from the emulator / a device over WiFi.

Let’s get me some Windows Phone!

We’re up and running, so time to get our hands dirty with some C# code. Open Visual Studio and start a new C# Windows Phone application targetting “Windows Phone 7l.1″ (which is the code target name for Mango). The project that we create is going to do something extremely simple – it’s going to open the socket, send a request for data (it’s really a dummy request since this server isn’t really waiting for a real request) and then displays the response, verbatim, on the screen.

Once you have the project created add a button (btnStart), which will kick the whole process off, and a textblock (txtServerResponse) to contain the server response. We’re not going to use binding to simplify the sample, but you can certainly do that instead. Add a Click handler to the button by double clicking on it and add the following code to MainPage.xaml.cs. The code is heavily documented so should answer any further questions you might have. I’ve also stuck a zipped version of the project (including the mini-server) which you can use to experiment with.

private Socket _socket;

private void btnStart_Click(object sender, RoutedEventArgs e)
{
    // the message to send to the server
    byte[] message = UTF8Encoding.UTF8.GetBytes("GET / HTTP/1.1\nHost: localhost\n\n");

    // the address we'll be connecting to
    IPAddress address  = new IPAddress(new byte[] {192, 168, 2, 125});

    // an endpoint translates into the complete destination - address + port
    // you can also use a DnsEndpoint to look up an IP address from a hostname
    IPEndPoint endpoint = new IPEndPoint(address, 1337);

    // all socket operations are asynchronous on the phone so you must set up 
    // a SocketAsyncEventArgs object to let the socket know how to act
    SocketAsyncEventArgs args = new SocketAsyncEventArgs() { RemoteEndPoint = endpoint };

    // don't allow multiple clicks before the request finishes
    btnStart.IsEnabled = false;

    // create our socket, note that it isn't connected yet
    _socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

    // set up the call back to be called when we finish connecting to the socket
    args.Completed += new EventHandler<SocketAsyncEventArgs>(OnSocketConnected);

    // neat trick - setting the buffer of a socket before it connects will cause the socket to send
    // that data as soon as it connects
    args.SetBuffer(message, 0, message.Length);

    // boom! we're off
    _socket.ConnectAsync(args);
}

void OnSocketConnected(object sender, SocketAsyncEventArgs e)
{
    if (e.SocketError != SocketError.Success)
    {
        // don't forget that we're now on a background thread so anything that interacts with
        // the UI thread (MessageBoxes, updating UI etc) has to be dispatched back
        Dispatcher.BeginInvoke(() =>
        {
            MessageBox.Show("(Connect) Socket error! " + e.SocketError.ToString());
        });
        return;
    }

    // we're done with the connect + send, time to receive

    // create a buffer for the respone
    byte[] buffer = new byte[1024];

    // create the Socket event args for this receive
    SocketAsyncEventArgs args = new SocketAsyncEventArgs();

    // set a buffer for the receive - the size will be the maximum amount read
    args.SetBuffer(buffer, 0, 1024);

    // we have to come back somewhere after the receive completed
    args.Completed += new EventHandler<SocketAsyncEventArgs>(OnSocketReceive);

    // kick off the actual receive
    _socket.ReceiveAsync(args);
}

void OnSocketReceive(object sender, SocketAsyncEventArgs e)
{
    if (e.SocketError != SocketError.Success)
    {
        Dispatcher.BeginInvoke(() =>
        {
            MessageBox.Show("(Receive) Socket error! " + e.SocketError.ToString());
        });

        return;
    }

    // the response comes back as a byte array, so convert it to a string
    // Note: usually you would read from the buffer and then call _socket.ReceiveAsync(e)
    // again until e.BytesTransferred == 0 (signals end of the receive), for this example
    // we're going to keep it simple
    string response = UTF8Encoding.UTF8.GetString(e.Buffer, 0, e.BytesTransferred - 1);

    // we have our response now update the UI thread
    Dispatcher.BeginInvoke(() =>
    {
        txtServerResponse.Text = response;
        btnStart.IsEnabled     = true;
    });
}

What does it look like?


Questions?

Feel free to leave comments below – Good Luck!

Download the solution + js file

Oren Categories: Dev Tips, Silverlight, Windows Phone Tags:

Marketplace Updates Galore! More Free Apps, No need for Support in your app

February 24th, 2011 No comments

Woo! All registered Marketplace should have gotten their regular newsletter which this time comes packed with goodies:

  1. Free app submissions ramped from 5 to 100! The assumption here is that this is submissions and not actual apps (so if you fail an initial submission you lose a token), but updates are still unlimited.
  2. You’ll no longer fail certification if you don’t include support contact information. I honestly think this is a bad move (how hard is it to setup an email?) but there if you have it – at least people will no longer fail certification because of it!
  3. We’ve partnered with Zones.com to get phones that don’t require a contract. Visit: http://www.zones.com/windowsphonedeveloperpurchase for more information
  4. If you’re part of a user group you’re going to want to check out this competition that nets you $100 for your UG for every submitted app: http://www.telerik.com/products/windows-phone/getting-started/user-groups.aspx

Now – let’s hope that every newsletter brings these kinds of updates!

Oren Categories: Marketplace, Windows Phone Tags:

Marketplace FAQ: What do the different app statuses mean?

February 1st, 2011 No comments
Now that we’re out of the woods with the unlimited free app updates policy being clarified, it’s time to go back to our Marketplace roots and clear up some misconceptions around the different statuses that your app can have as it passes through certification.
 
 
“Submission In Progress” – this is an app that you’ve started the submission progress for, but have not completed, so the app will not be ready to submit until you go through the full submission form. To do this, click “View details” (under “action” on your dashboard), then click “Edit Submission” (again, under “Action”) and run through form. Note that you may encounter a stage where the current form is complete but the “Next” button is not activated (I get this a lot on the screenshot page), simply refill on of the fields (for example, add a dummy screenshot and then remove it).
 
“Ready for Testing” – You’ve successfully passed the first hurdle in getting your app onto the Marketplace, your XAP has been submitted and is (duh!) “Ready for Testing”. It will soon be picked up and your status will move to…
 
“Testing in Progress” – Your XAP has moved along and is currently being tested. The amount of time it takes to have an app go through will vary depending on the app. I have found that it will tend to come back to you quicker when failing (i.e. as soon as there is a problem) otherwise it usually finishes certification within a couple of days to a week.
 
“Ready for Signing” – Congratulations! You’ve passed testing, your app is certified. It’s now going to go through the last technical stage where the XAP is signed and prepared for the Marketplace. This is largely automatic and should be finished within a few hours.
 
“Published to Marketplace” – Break out the champagne! Your app is in the marketplace and you’re now ready to move on to vNext or appNext. Note that it can take up to 12 hours for your application to show up in the search index, so don’t fret if it takes a while.
 
“Certification Failed” – oh oh, an issue was found in your app while running through the certification process. On the submission details page you’ll find a testing report in the drop under “action” which will detail exactly what was wrong, and the steps to repro the problem. I’ll admit that I was impressed with the reason for one of my failures (clicking multiple times, very quickly, on a button caused the app to crash) and with the way the report detailed the exact problem so that I could find it, fix it and resubmit asap. That said, sometimes there are mistakes made or unclear reports and in this case the support team are your friends.
 
 
How long does certification usually take?
Certification shouldn’t take more than 7 days, with the average being a lot lower than that. My record is currently 13 hours (submitted at 2am, on the marketplace by 3pm), though the average that I see reported is 3-4 days.
What should I do if it’s taking more than 7 days?
First, DON’T PANIC. That said, if you’re app is taking more than 10 days, log a support request to find out what’s happened. There’s a possibility that there was a problem with the file upload which will require you to resubmit your xap, but at least you’ll know that things are moving!
 
Logging a Support Request
To log a support request login to create.msdn.com -> My dashboard -> Windows Phone and then hit the “Support” link on the left menu. You should get an initial response within 24 hours (if you haven’t gotten a response after 48 hours, log another request).
 
Run into any marketplace tips / tricks? How about some annoyances? Drop me a comment and I’ll see if I can address them in a future blog post (before I head back to writing about perf!).
Oren Categories: Marketplace, Windows Phone Tags:

WP7 Marketplace Tip: Submitted a support request and never heard back?

January 26th, 2011 No comments

If you submitted a request via AppHub, to either the “Device Unlock” or “Account Management” categories and never heard back then your request has most likely gotten stuck somewhere.

So What Do I Do?

The problem has been found and will be fixed by Friday – so resubmit your request any time after Friday and you should hear back from the team within approximately 24 hours.

Do I need to resubmit, or will my old, unanswered, requests suddenly be answered?

You will need to resubmit – existing, unanswered, requests (only in those two categories) will not be processed.

Good Luck!

Oren Categories: Marketplace, Windows Phone Tags:

WP Marketplace FAQ: What happens to my apps if I don’t renew my subscription

January 20th, 2011 No comments

The Question

I’ve signed up for the Windows Phone marketplace and submitted my apps. They’re selling well – but I’m not actually planning on doing any more development, so I don’t think I need to renew my subscription. What happens if I don’t pay the Marketplace renewal fee at the end of the year?

The Answer

You’ll get a couple of warning emails at the end of the year, but after those if you choose not to renew your subscription your apps will be removed from the Marketplace.

Will people still be able to use my apps?

Sure. Microsoft won’t revoke the apps from people’s phones, but they will remove it from the Marketplace – so no one new will be able to purchase the app (and, obviously, no more revenue for you if it was a paid app).

Oren Categories: Marketplace, Windows Phone Tags:

WP7 Marketplace FAQ: Do my free app submissions reset every year?

January 17th, 2011 4 comments

Summary

Yes.

Seriously?

Yup, you get 5 free submission credits a year, so every year you could potentially submit another 5 free applications to the marketplace (not to mention the unlimited free updates to existing free applications).

Can I see how many submission credits I have left?

Not at this point, though I hope to see this soon. For now, if you can’t remember where you’re up to, submit a support request and the team will get back to you asap (usually within 24 hours) with an answer.

Is your head spinning with all the free yet?

Oren Categories: Marketplace, Windows Phone Tags:

SL WP7 Toolkit Pro Tip: Set a background on your LongListSelector so that it scrolls correctly

January 16th, 2011 No comments

Got a LongListSelector in your project? Notice that if you try to scroll in blank areas (where the background shows through) it won’t react?

Set:

Background=”{StaticResource PhoneBackgroundBrush}”

or to whatever colour you prefer and all your problems should go away.

Oren Categories: Dev Tips, Windows Phone Tags:

WP7 Marketplace Tip #4: Include Contact info in your next app update

January 11th, 2011 No comments

Summary

Make sure that you include the app name, version and technical support contact info within your app (or your next update)

The Fine Print

Section 5.6 says:

An application must include the application name, version information, and technical support contact information that are easily discoverable.

But my app was approved without this?

This was a late introduction into the certification guide (a couple of weeks before launch) so it hasn’t been enforced up till now. That said, it’s now been long enough since release for everyone to be able to have time to add the information so expect to see apps failing if you forget to include this information.

How do I do this?

Well, that’s the easy part, simply include an About page or Contact Us page. For contact you can send them to a forum link:

WebBrowserTask browser = new WebBrowserTask();
browser.URL = "http://somepublisher/forum";
browser.Show();

Or an email address:

EmailComposeTask emailComposeTask = new EmailComposeTask();
emailComposeTask.To = "Publisher <feedback@publisher.com>";
emailComposeTask.Subject = "Feedback About [Some App]";
emailComposeTask.Body = "";
emailComposeTask.Show();

When using tasks don’t forget to wrap it in a try/catch statement.

Oren Categories: Uncategorized Tags:

WP7 Silverlight Gotcha: Using the ListPicker from the Toolkit may cause you to fail certification

January 9th, 2011 No comments

Applies To: Anyone using the current iteration of the Silverlight Tookit from Nov 2010

Toolkit Link: http://silverlight.codeplex.com/releases

Quick Bits

A Toolkit ListPicker control that has less than 5 items in it will display inline (expands) but will not collapse when you press the back button (like the native control does). This can cause you to fail certification due to an erroneous interpretation of the certification guide.

The Fine Print

According to section 5.2.4c the following applies to the use of the Back Button:

If the current page displays a context menu or a dialog, the pressing of the Back button must close the menu or dialog and cancel the backward navigation to the previous page.

The Setup

You have a ListPicker with less than 5 items in it, using the standard Silverlight Toolkit library.

The Sting

The Toolkit ListPicker doesn’t listen for the back button when the ListPicker is in mini mode (i.e. it doesn’t pop up the full screen list picker), so when you press back normal navigation occurs.

The Solution

There will be an update to the Toolkit coming out sometime this month that will address the issue, but if you want a fix now you basically need to either fix the Toolkit or listen in on the navigation event (and then check if a ListPicker is expanded and if so collapse it). I prefer the first option, since it’s easy and you don’t need to write redundant code if you have heaps of ListPickers.

To this end, you can download a patched ListPicker.cs file (replace this within your Toolkit Source project), or a built Toolkit DLL (unzip and replace your Toolkit installation under C:\Program Files (x86)\Microsoft SDKs\Windows Phone\v7.0\Toolkit\Nov10\Bin), with one change – the ListPicker will now respect the back button.

Does It Really Matter for Certification?

Actually, no. My reading of the certification guide doesn’t indicate in any way that this is the expected behaviour, not to mention that I (and a bunch of other people) have other apps that were approved with the same control!

So, I fought the good fight, and lodged a support request (complaint) and got the following response:

Dear Oren,

I am sorry for the inconveniences you experienced! It seems that there was a little misunderstanding during certification testing. Dropdown list or list control does not need to be collapsed at Back button press and instead its previous screen can come up or if the back button was pressed from the application’s first page, it can exit the application. Please add a short tester note while submitting it explaining that the list control is not dialog and does not need to be closed.
We will also instruct our test team to correctly apply different expectations for list controls.
Thanks,
Windows Phone Marketplace Certification

I was impressed (I don’t think they even knew I was from within Microsoft)!

WP7 Marketplace Tip #3: Free app updates are free, even if they fail!

January 8th, 2011 No comments

This has finally been clarified by the Marketplace team as the most current, up to date, lore on the subject of free app updates – they’re free, they don’t count towards your 5 free submissions, even if they fail. Here’s the word for word story straight from a Marketplace PM:

Paid Developer (USD$99):

1.     Unlimited number of paid applications.   You cannot change the price on a paid app to be free.

2.     Updates to paid apps that have been published are no charge.

3.     5 submission credits for free apps

4.     Updates to free apps that have been published are no charge.

DreamSpark (free):

1.     Unlimited number of paid applications.   You cannot change the price on a paid app to be free.

2.     Updates to paid apps that have been published are no charge.

3.     5 submission credits for free apps

4.     Updates to free apps that have been published are no charge.

* the failed updates for free apps are not  accounted against the developer quota

What do I do if I get charged for an update to a free app?

Submit a support request via the portal and you should get a response within 24 hours. Feel free to reference this blog post if needed.

Oren Categories: Marketplace, Windows Phone Tags: