Monitoring iPhone web traffic (with Fiddler)

For reasons that will become apparent in a future post, I wanted to 'sniff' the web traffic coming from my iPhone. If you are already familiar with Fiddler (web debugging proxy) you probably already know how easy that is to do. For everyone else, here's a brief rundown of the steps involved:

1. Get Fiddler
Download Fiddler and install it on your PC (with Windows 2000 / XP / 2003 / Vista and Microsoft .NET Framework v2.0 or later)

2. Set-up Fiddler
Start Fiddler then open the Fiddler Options... window


and in the General tab, ensure Allow remote computers to connect is checked.


In the Connections tab, check Act as system proxy on startup and verify what port is set (eg. 8888).

Once you've saved those settings you need to stop and re-start Fiddler.

3. Ensure Fiddler is 'listening'
Once Fiddler has re-started, verify that the Capture Traffic menuitem is ticked.


4. Check the 'listening' IP
You need to know your computer's wireless-network IP address to configure the iPhone. This screenshots shows the Command Prompt > ipconfig output:


5. Set-up iPhone Settings
With the computer IP address and Fiddler port, go to your iPhone's Wifi Settings and scroll down to the HTTP Proxy, choose Manual and input the Fiddler proxy info:

(remember to switch back to Off when you're done)

6. 'sniff' away
If everything has been setup right, anything you do in Safari or other internet applications (like, say Microsoft Tag Reader) will be logged in the Fiddler window.


It's extremely useful for testing/debugging - have fun!

Don't forget to UNDO the iPhone settings when you're finished!!

DeepZoom "Viewer" 1.1

Deep Zoom Viewer has been updated to version 1.1!


It is still only beta-grade software (bug reports welcome) but a few new features have been added:

1. Easier to install
There is now a ClickOnce installer (with the .NET 3.5 SP1 Client Profile set as a pre-requisite). The ClickOnce installer also creates file associations on .DZI and .DZC - double-clicking on these should open them directly in Deep Zoom Viewer.
You can also just download a ZIP file (v1.2) if you prefer.

2. Loading of PhotoZoom by username
Just type a PhotoZoom username (like Craig) to explore the Deep Zoom images created on Microsoft's server-based Deep Zoom site.


3. Image attributes and metadata
Depending on whether you are viewing 'local' or internet-hosted Deep Zoom files, different file information (size, date) and metadata (if created in Deep Zoom Composer) is visible. Clicking on the underlined Location will open the image or tile in a new window.


4. Recent Files menu
Minor convenience...


Hope somebody finds it useful.

EDIT [29-Jan-09] v1.2 released (ZIP only) links updated. ClickOnce is still 1.1 as there seem to be some network connectivity issues when the application is started via ClickOnce...

Calculating distance in C# (with SqlServer.Types)

WiredPrairie's post on Calculating the distance between two Zip Codes in C# starts with the line

Unfortunately, there are many classes built into the .NET framework, but a zip code distance calculator isn’t included.

which is true -- however with the release of SQL Server 2008 Microsoft has made available the redistributable Microsoft.SqlServer.Types assembly that contains the SqlGeography and SqlGeometry types. Within SQL Server 2008 this enables the new geospatial functions, but these types can also be used in C#. I thought I'd add the SQL Server types to his example, just for fun...

I've modified WiredPrairie's code to use Microsoft.SqlServer.Types.SqlGeography in place of manually calculating Radians and using the Haversine formula... only a few minor changes were required (view source):

0. Reference Microsoft.SqlServer.Types assembly


1. Replace the Distance() method completely
I haven't implemented miles here - just kilometres

The important bits being:

string lineString = String.Format("LINESTRING({0} {1}, {2} {3})"
    , compare.Longitude, compare.Latitude
    , this.Longitude, this.Latitude);
var g = Microsoft.SqlServer.Types.SqlGeography.STGeomFromText(
        new System.Data.SqlTypes.SqlChars(new System.Data.SqlTypes.SqlString(
            lineString
        ))
    , 4326); // IMPORTANT for distance calc
geoDistance = Convert.ToDouble(g.STLength().ToString()) / 1000; // to kilometers

2. Remove the conversion to Radians
The SqlGeography type uses Latitude and Longitude in degrees.


3. Minor text changes (miles to kilometres)


4. and finally, change the input from '25 miles' to '40 kilometres'
Here is a comparison of the results -- there appears to minor differences in the calculation results - I assume due to rounding...


Of course, WiredPrairie's solution would run anywhere (including Silverlight) whereas adding a dependency to Microsoft.SqlServer.Types means you can only use this code where the SqlServer Types redistributable has been installed. It's still interesting to see the additional features provided by SQL Server 2008 - I hope some spatial types (without the SQL dependency) make their way into a future core .NET Framework release (and Silverlight 3.0??).

Great Circles!

No, I'm not over-excited about a shape... Great Circles are a 'geographic concept' (via The Map Room).

A great circle is defined as any circle drawn on a globe (or other sphere) with a center that includes the center of the globe. Thus, a great circle divides the globe into two equal halves.

The post reminded me that some additional work on Geoquery 2008 is long overdue. Until then, it prompted me to blog my 'great circle drawing algorithm' as used in Geoquery 2008 to draw lines like this (a 'straight line' between two points, which looks curved on a Mercator projection but is clearly straight when viewed from above on a globe):

The above example uses SQL Server 2008's STBuffer() geography function - notice how the shaded area looks kidney-shaped on the 'flat' Mercator projection (the curve is more pronounced further north) but on the globe the sides are straight.

You can read the C# code to calculate a Great Circle arc or see it below. Given two System.Windows.Points on a Mercator grid (following the Virtual Earth 'scaling' pattern - notice the hardcoded zoomlevel 2 in the LatLongToPixel method calls) it will calculate a Great Circle between them and plot 10 points along that path (notice the hardcoded 0.1 in the for clause). It returns a System.Windows.Shapes.Polyline ready to draw!


It references Virtual Earth Tile System, and the algorithm itself is based on the work by Ed Williams on Aviation Formulary in particular calculating intermediate points on a great circle.

For those who are really paying attention, you may guess this isn't exactly the code used in Geoquery 2008... for a start 10 divisions was too coarse so Geoquery uses a variable number of points based on the length of the line and its proximity to the poles (where the 'curve' is more pronounced). Geoquery ALSO needs to stop/start drawing lines that cross Longitude 180° (so they wrap nicely on Mercator, and join when projected on a globe)... which is done by calculating the intersection of two great circles because SQL Server 2008 couldn't do it (but that's another story...)

P.S. there are some previous posts on the 'straight line' problem that might be an interesting read...

DeepZoom "Viewer"

My MIX09 Silverlight entry - exploDZ hasn't exactly set the voting world on fire :)

However I still think it's a useful concept, so a Wpf version is now available for download at deepzoompublisher.com/Viewer (zip).



It's pretty simple - open local or remote Deep Zoom Composer Xml output and browse around its contents. You can always try the Silverlight version too - here's a test Url to get started http://deepzoompublisher.com/ClientBin/Cities/dzc_output.xml

DeepZoomTools.dll

Deep Zoom Publisher is currently getting 'upgraded' to use DeepZoomTools.dll instead of the rather clumsy "old way":

// the old way
System.Diagnostics.Process p = new Process();
p.StartInfo.FileName = 
  @"C:\Program Files\Microsoft Corporation\Deep Zoom Composer\sparseimagetool.exe";
p.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
p.StartInfo.Arguments = String.Format(
                        @"CreateCollection  ""{0}"" ""{1}"" ", 
                        filename, sdiname);

It works a lot better, however I was initially stumped by an error message from the Microsoft.DeepZoomTools.CollectionCreator.Create() method:
Invalid character in the given encoding. Line 1, position 1.
at System.Xml.XmlTextReaderImpl.Throw(Exception e) ...
at System.Xml.XmlTextReaderImpl.InvalidCharRecovery(Int32& bytesCount, Int32& charsCount)
at System.Xml.XmlTextReaderImpl.GetChars(Int32 maxCharsCount)
at System.Xml.XmlTextReaderImpl.Read() ...
at Microsoft.DeepZoomTools.CollectionCreator.Create(ICollection`1 images, String destination)

My initial attempt at the code was as follows:

var cc = new Microsoft.DeepZoomTools.CollectionCreator();
var imgs = new List();
var sdiname = proj.GetSdiFilename(); // custom
foreach (var f in proj.ImageList)
{
    imgs.Add(new Image(f.File));
}
cc.Create(imgs, sdiname);

but the error is thrown on the cc.Create line.

Turns out to be a case of RTFM... the Expression blog specifically says

one thing that confused me was what CollectionCreator expected as its “image path”. It isn’t a string of paths to raw JPG, PNG, etc. files. It is actually a path to the Deep Zoom Image created via ImageCreator/SparseImageCreator. SparseImageCreator does take in a list of paths to the source image, so passing in a list of image files will work for generating sparse images (aka Compositions)

Bryant also had it figured out in his example... although it seems to me like the API is a little inconsistent (as the quote says). It is a preview release, so I expect this API will change soon enough...

This code works:

var cc = new Microsoft.DeepZoomTools.CollectionCreator();
var ic = new ImageCreator();
var imgs = new List();
var sdiname = proj.GetSdiFilename(); // custom
foreach (var f in proj.ImageList)
{
    string fn = Path.GetDirectoryName(sdiname) 
             + @"\" + 
             GetFileNameWithoutExtension(f.File) + ".xml";
    ic.Create(f.File, fn);
    imgs.Add(new Image(fn));
}
cc.Create(imgs, sdiname);

More Deep Zoom Publisher to come...

OT: of course before DeepZoomTools.dll there was Berend's CodeProject article...