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• understand SimpleTimeZone and DST Test

  - by Cygnusx1

  I Have an issue with the use of SimpleTimeZone class in Java. First, the JavaDoc is nice but not quite easy to understand in regards of the start and end Rules. But with the help of some example found on the web, i managed to get it right (i still don't understand why 8 represents the second week of a month in day_of_month!!! but whatever) Now i have written a simple Junit test to validate what i understand: package test; import static org.junit.Assert.assertEquals; import java.sql.Timestamp; import java.util.Calendar; import java.util.GregorianCalendar; import java.util.SimpleTimeZone; import org.apache.log4j.Logger; import org.junit.Test; public class SimpleTimeZoneTest { Logger log = Logger.getLogger(SimpleTimeZoneTest.class); @Test public void testTimeZoneWithDST() throws Exception { Calendar testDateEndOut = new GregorianCalendar(2012, Calendar.NOVEMBER, 4, 01, 59, 59); Calendar testDateEndIn = new GregorianCalendar(2012, Calendar.NOVEMBER, 4, 02, 00, 00); Calendar testDateStartOut = new GregorianCalendar(2012, Calendar.MARCH, 11, 01, 59, 59); Calendar testDateStartIn = new GregorianCalendar(2012, Calendar.MARCH, 11, 02, 00, 00); SimpleTimeZone est = new SimpleTimeZone(-5 * 60 * 60 * 1000, "EST"); est.setStartRule(Calendar.MARCH, 8, -Calendar.SUNDAY, 2 * 60 * 60 * 1000); est.setEndRule(Calendar.NOVEMBER, 1, Calendar.SUNDAY, 2 * 60 * 60 * 1000); Calendar theCal = new GregorianCalendar(est); theCal.setTimeInMillis(testDateEndOut.getTimeInMillis()); log.info(" Cal date = " + new Timestamp(theCal.getTimeInMillis()) + " : " + theCal.getTimeZone().getDisplayName()); log.info(" Cal use DST = " + theCal.getTimeZone().useDaylightTime()); log.info(" Cal In DST = " + theCal.getTimeZone().inDaylightTime(theCal.getTime())); log.info("offset = " + theCal.getTimeZone().getOffset(theCal.getTimeInMillis())); log.info("DTS offset= " + theCal.getTimeZone().getDSTSavings()); assertEquals("End date Should be In DST", true, theCal.getTimeZone().inDaylightTime(theCal.getTime())); theCal.setTimeInMillis(testDateEndIn.getTimeInMillis()); log.info(" Cal date = " + new Timestamp(theCal.getTimeInMillis()) + " : " + theCal.getTimeZone().getDisplayName()); log.info(" Cal use DST = " + theCal.getTimeZone().useDaylightTime()); log.info(" Cal In DST = " + theCal.getTimeZone().inDaylightTime(theCal.getTime())); log.info("offset = " + theCal.getTimeZone().getOffset(theCal.getTimeInMillis())); log.info("DTS offset= " + theCal.getTimeZone().getDSTSavings()); assertEquals("End date Should be Out DST", false, theCal.getTimeZone().inDaylightTime(theCal.getTime())); theCal.setTimeInMillis(testDateStartIn.getTimeInMillis()); log.info(" Cal date = " + new Timestamp(theCal.getTimeInMillis()) + " : " + theCal.getTimeZone().getDisplayName()); log.info(" Cal use DST = " + theCal.getTimeZone().useDaylightTime()); log.info(" Cal In DST = " + theCal.getTimeZone().inDaylightTime(theCal.getTime())); log.info("offset = " + theCal.getTimeZone().getOffset(theCal.getTimeInMillis())); log.info("DTS offset= " + theCal.getTimeZone().getDSTSavings()); assertEquals("Start date Should be in DST", true, theCal.getTimeZone().inDaylightTime(theCal.getTime())); theCal.setTimeInMillis(testDateStartOut.getTimeInMillis()); log.info(" Cal date = " + new Timestamp(theCal.getTimeInMillis()) + " : " + theCal.getTimeZone().getDisplayName()); log.info(" Cal use DST = " + theCal.getTimeZone().useDaylightTime()); log.info(" Cal In DST = " + theCal.getTimeZone().inDaylightTime(theCal.getTime())); log.info("offset = " + theCal.getTimeZone().getOffset(theCal.getTimeInMillis())); log.info("DTS offset= " + theCal.getTimeZone().getDSTSavings()); assertEquals("Start date Should be Out DST", false, theCal.getTimeZone().inDaylightTime(theCal.getTime())); } } Ok, i want to test the date limits to see if the inDaylightTime return the right thing! So, my rules are : DST start the second sunday of March at 2am DST end the first sunday of november at 2am In 2012 (now) this give us the march 11 at 2am and November 4 at 2am You can see my test dates are set properly!!! Well here is the output of my test run: 2012-11-01 18:22:44,344 INFO [test.SimpleTimeZoneTest] - < Cal date = 2012-11-04 01:59:59.0 : Eastern Standard Time> 2012-11-01 18:22:44,345 INFO [test.SimpleTimeZoneTest] - < Cal use DST = true> 2012-11-01 18:22:44,345 INFO [test.SimpleTimeZoneTest] - < Cal In DST = false> 2012-11-01 18:22:44,345 INFO [test.SimpleTimeZoneTest] - <offset = -18000000> 2012-11-01 18:22:44,345 INFO [test.SimpleTimeZoneTest] - <DTS offset= 3600000> My first assert just fails and tell me that 2012-11-04 01:59:59 is not inDST... !!!!??? If i put 2012-11-04 00:59:59, the test pass! This 1 hour gap just puzzle me... can anyone explain this behavior? Oh, btw, if anyone could elaborate on the : est.setStartRule(Calendar.MARCH, 8, -Calendar.SUNDAY, 2 * 60 * 60 * 1000); Why 8 means second week of march... and the -SUNDAY. I can't figure out this thing on a real calendar example!!! Thanks

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• Approaches for generic, compile-time safe lazy-load methods

  - by Aaronaught

  Suppose I have created a wrapper class like the following: public class Foo : IFoo { private readonly IFoo innerFoo; public Foo(IFoo innerFoo) { this.innerFoo = innerFoo; } public int? Bar { get; set; } public int? Baz { get; set; } } The idea here is that the innerFoo might wrap data-access methods or something similarly expensive, and I only want its GetBar and GetBaz methods to be invoked once. So I want to create another wrapper around it, which will save the values obtained on the first run. It's simple enough to do this, of course: int IFoo.GetBar() { if ((Bar == null) && (innerFoo != null)) Bar = innerFoo.GetBar(); return Bar ?? 0; } int IFoo.GetBaz() { if ((Baz == null) && (innerFoo != null)) Baz = innerFoo.GetBaz(); return Baz ?? 0; } But it gets pretty repetitive if I'm doing this with 10 different properties and 30 different wrappers. So I figured, hey, let's make this generic: T LazyLoad<T>(ref T prop, Func<IFoo, T> loader) { if ((prop == null) && (innerFoo != null)) prop = loader(innerFoo); return prop; } Which almost gets me where I want, but not quite, because you can't ref an auto-property (or any property at all). In other words, I can't write this: int IFoo.GetBar() { return LazyLoad(ref Bar, f => f.GetBar()); // <--- Won't compile } Instead, I'd have to change Bar to have an explicit backing field and write explicit getters and setters. Which is fine, except for the fact that I end up writing even more redundant code than I was writing in the first place. Then I considered the possibility of using expression trees: T LazyLoad<T>(Expression<Func<T>> propExpr, Func<IFoo, T> loader) { var memberExpression = propExpr.Body as MemberExpression; if (memberExpression != null) { // Use Reflection to inspect/set the property } } This plays nice with refactoring - it'll work great if I do this: return LazyLoad(f => f.Bar, f => f.GetBar()); But it's not actually safe, because someone less clever (i.e. myself in 3 days from now when I inevitably forget how this is implemented internally) could decide to write this instead: return LazyLoad(f => 3, f => f.GetBar()); Which is either going to crash or result in unexpected/undefined behaviour, depending on how defensively I write the LazyLoad method. So I don't really like this approach either, because it leads to the possibility of runtime errors which would have been prevented in the first attempt. It also relies on Reflection, which feels a little dirty here, even though this code is admittedly not performance-sensitive. Now I could also decide to go all-out and use DynamicProxy to do method interception and not have to write any code, and in fact I already do this in some applications. But this code is residing in a core library which many other assemblies depend on, and it seems horribly wrong to be introducing this kind of complexity at such a low level. Separating the interceptor-based implementation from the IFoo interface by putting it into its own assembly doesn't really help; the fact is that this very class is still going to be used all over the place, must be used, so this isn't one of those problems that could be trivially solved with a little DI magic. The last option I've already thought of would be to have a method like: T LazyLoad<T>(Func<T> getter, Action<T> setter, Func<IFoo, T> loader) { ... } This option is very "meh" as well - it avoids Reflection but is still error-prone, and it doesn't really reduce the repetition that much. It's almost as bad as having to write explicit getters and setters for each property. Maybe I'm just being incredibly nit-picky, but this application is still in its early stages, and it's going to grow substantially over time, and I really want to keep the code squeaky-clean. Bottom line: I'm at an impasse, looking for other ideas. Question: Is there any way to clean up the lazy-loading code at the top, such that the implementation will: Guarantee compile-time safety, like the ref version; Actually reduce the amount of code repetition, like the Expression version; and Not take on any significant additional dependencies? In other words, is there a way to do this just using regular C# language features and possibly a few small helper classes? Or am I just going to have to accept that there's a trade-off here and strike one of the above requirements from the list?

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• C# Generic Arrays and math operations on it

  - by msedi

  Hello, I'm currently involved in a project where I have very large image volumes. This volumes have to processed very fast (adding, subtracting, thresholding, and so on). Additionally most of the volume are so large that they event don't fit into the memory of the system. For that reason I have created an abstract volume class (VoxelVolume) that host the volume and image data and overloads the operators so that it's possible to perform the regular mathematical operations on volumes. Thereby two more questions opened up which I will put into stackoverflow into two additional threads. Here is my first question. My volume is implemented in a way that it only can contain float array data, but most of the containing data is from an UInt16 image source. Only operations on the volume can create float array images. When I started implementing such a volume the class looked like following: public abstract class VoxelVolume<T> { ... } but then I realized that overloading the operators or return values would get more complicated. An example would be: public abstract class VoxelVolume<T> { ... public static VoxelVolume<T> Import<T>(param string[] files) { } } also adding two overloading operators would be more complicated: ... public static VoxelVolume<T> operator+(VoxelVolume<T> A, VoxelVolume<T> B) { ... } Let's assume I can overcome the problems described above, nevertheless I have different types of arrays that contain the image data. Since I have fixed my type in the volumes to float the is no problem and I can do an unsafe operation when adding the contents of two image volume arrays. I have read a few threads here and had a look around the web, but found no real good explanation of what to do when I want to add two arrays of different types in a fast way. Unfortunately every math operation on generics is not possible, since C# is not able to calculate the size of the underlying data type. Of course there might by a way around this problem by using C++/CLR, but currently everything I have done so far, runs in 32bit and 64bit without having to do a thing. Switching to C++/CLR seemed to me (pleased correct me if I'm wrong) that I'm bound to a certain platform (32bit) and I have to compile two assemblies when I let the application run on another platform (64bit). Is this true? So asked shortly: How is it possible to add two arrays of two different types in a fast way. Is it true that the developers of C# haven't thought about this. Switching to a different language (C# - C++) seems not to be an option. I realize that simply performing this operation float []A = new float[]{1,2,3}; byte []B = new byte[]{1,2,3}; float []C = A+B; is not possible and unnecessary although it would be nice if it would work. My solution I was trying was following: public static class ArrayExt { public static unsafe TResult[] Add<T1, T2, TResult>(T1 []A, T2 []B) { // Assume the length of both arrays is equal TResult[] result = new TResult[A.Length]; GCHandle h1 = GCHandle.Alloc (A, Pinned); GCHandle h2 = GCHandle.Alloc (B, Pinned); GCHandle hR = GCHandle.Alloc (C, Pinned); void *ptrA = h1.ToPointer(); void *ptrB = h2.ToPointer(); void *ptrR = hR.ToPointer(); for (int i=0; i<A.Length; i++) { *((TResult *)ptrR) = (TResult *)((T1)*ptrA + (T2)*ptrB)); } h1.Free(); h2.Free(); hR.Free(); return result; } } Please excuse if the code above is not quite correct, I wrote it without using an C# editor. Is such a solution a shown above thinkable? Please feel free to ask if I made a mistake or described some things incompletely. Thanks for your help Martin

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• Modelling boost::Lockable with semaphore rather than mutex (previously titled: Unlocking a mutex fr

  - by dan

  I'm using the C++ boost::thread library, which in my case means I'm using pthreads. Officially, a mutex must be unlocked from the same thread which locks it, and I want the effect of being able to lock in one thread and then unlock in another. There are many ways to accomplish this. One possibility would be to write a new mutex class which allows this behavior. For example: class inter_thread_mutex{ bool locked; boost::mutex mx; boost::condition_variable cv; public: void lock(){ boost::unique_lock<boost::mutex> lck(mx); while(locked) cv.wait(lck); locked=true; } void unlock(){ { boost::lock_guard<boost::mutex> lck(mx); if(!locked) error(); locked=false; } cv.notify_one(); } // bool try_lock(); void error(); etc. } I should point out that the above code doesn't guarantee FIFO access, since if one thread calls lock() while another calls unlock(), this first thread may acquire the lock ahead of other threads which are waiting. (Come to think of it, the boost::thread documentation doesn't appear to make any explicit scheduling guarantees for either mutexes or condition variables). But let's just ignore that (and any other bugs) for now. My question is, if I decide to go this route, would I be able to use such a mutex as a model for the boost Lockable concept. For example, would anything go wrong if I use a boost::unique_lock< inter_thread_mutex for RAII-style access, and then pass this lock to boost::condition_variable_any.wait(), etc. On one hand I don't see why not. On the other hand, "I don't see why not" is usually a very bad way of determining whether something will work. The reason I ask is that if it turns out that I have to write wrapper classes for RAII locks and condition variables and whatever else, then I'd rather just find some other way to achieve the same effect. EDIT: The kind of behavior I want is basically as follows. I have an object, and it needs to be locked whenever it is modified. I want to lock the object from one thread, and do some work on it. Then I want to keep the object locked while I tell another worker thread to complete the work. So the first thread can go on and do something else while the worker thread finishes up. When the worker thread gets done, it unlocks the mutex. And I want the transition to be seemless so nobody else can get the mutex lock in between when thread 1 starts the work and thread 2 completes it. Something like inter_thread_mutex seems like it would work, and it would also allow the program to interact with it as if it were an ordinary mutex. So it seems like a clean solution. If there's a better solution, I'd be happy to hear that also. EDIT AGAIN: The reason I need locks to begin with is that there are multiple master threads, and the locks are there to prevent them from accessing shared objects concurrently in invalid ways. So the code already uses loop-level lock-free sequencing of operations at the master thread level. Also, in the original implementation, there were no worker threads, and the mutexes were ordinary kosher mutexes. The inter_thread_thingy came up as an optimization, primarily to improve response time. In many cases, it was sufficient to guarantee that the "first part" of operation A, occurs before the "first part" of operation B. As a dumb example, say I punch object 1 and give it a black eye. Then I tell object 1 to change it's internal structure to reflect all the tissue damage. I don't want to wait around for the tissue damage before I move on to punch object 2. However, I do want the tissue damage to occur as part of the same operation; for example, in the interim, I don't want any other thread to reconfigure the object in such a way that would make tissue damage an invalid operation. (yes, this example is imperfect in many ways, and no I'm not working on a game) So we made the change to a model where ownership of an object can be passed to a worker thread to complete an operation, and it actually works quite nicely; each master thread is able to get a lot more operations done because it doesn't need to wait for them all to complete. And, since the event sequencing at the master thread level is still loop-based, it is easy to write high-level master-thread operations, as they can be based on the assumption that an operation is complete when the corresponding function call returns. Finally, I thought it would be nice to use inter_thread mutex/semaphore thingies using RAII with boost locks to encapsulate the necessary synchronization that is required to make the whole thing work.

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• Fast multi-window rendering with C#

  - by seb

  I've been searching and testing different kind of rendering libraries for C# days for many weeks now. So far I haven't found a single library that works well on multi-windowed rendering setups. The requirement is to be able to run the program on 12+ monitor setups (financial charting) without latencies on a fast computer. Each window needs to update multiple times every second. While doing this CPU needs to do lots of intensive and time critical tasks so some of the burden has to be shifted to GPUs. That's where hardware rendering steps in, in another words DirectX or OpenGL. I have tried GDI+ with windows forms and figured it's way too slow for my needs. I have tried OpenGL via OpenTK (on windows forms control) which seemed decently quick (I still have some tests to run on it) but painfully difficult to get working properly (hard to find/program good text rendering libraries). Recently I tried DirectX9, DirectX10 and Direct2D with Windows forms via SharpDX. I tried a separate device for each window and a single device/multiple swap chains approaches. All of these resulted in very poor performance on multiple windows. For example if I set target FPS to 20 and open 4 full screen windows on different monitors the whole operating system starts lagging very badly. Rendering is simply clearing the screen to black, no primitives rendered. CPU usage on this test was about 0% and GPU usage about 10%, I don't understand what is the bottleneck here? My development computer is very fast, i7 2700k, AMD HD7900, 16GB ram so the tests should definitely run on this one. In comparison I did some DirectX9 tests on C++/Win32 API one device/multiple swap chains and I could open 100 windows spread all over the 4-monitor workspace (with 3d teapot rotating on them) and still had perfectly responsible operating system (fps was dropping of course on the rendering windows quite badly to around 5 which is what I would expect running 100 simultaneous renderings). Does anyone know any good ways to do multi-windowed rendering on C# or am I forced to re-write my program in C++ to get that performance (major pain)? I guess I'm giving OpenGL another shot before I go the C++ route... I'll report any findings here. Test methods for reference: For C# DirectX one-device multiple swapchain test I used the method from this excellent answer: Display Different images per monitor directX 10 Direct3D10 version: I created the d3d10device and DXGIFactory like this: D3DDev = new SharpDX.Direct3D10.Device(SharpDX.Direct3D10.DriverType.Hardware, SharpDX.Direct3D10.DeviceCreationFlags.None); DXGIFac = new SharpDX.DXGI.Factory(); Then initialized the rendering windows like this: var scd = new SwapChainDescription(); scd.BufferCount = 1; scd.ModeDescription = new ModeDescription(control.Width, control.Height, new Rational(60, 1), Format.R8G8B8A8_UNorm); scd.IsWindowed = true; scd.OutputHandle = control.Handle; scd.SampleDescription = new SampleDescription(1, 0); scd.SwapEffect = SwapEffect.Discard; scd.Usage = Usage.RenderTargetOutput; SC = new SwapChain(Parent.DXGIFac, Parent.D3DDev, scd); var backBuffer = Texture2D.FromSwapChain<Texture2D>(SC, 0); _rt = new RenderTargetView(Parent.D3DDev, backBuffer); Drawing command executed on each rendering iteration is simply: Parent.D3DDev.ClearRenderTargetView(_rt, new Color4(0, 0, 0, 0)); SC.Present(0, SharpDX.DXGI.PresentFlags.None); DirectX9 version is very similar: Device initialization: PresentParameters par = new PresentParameters(); par.PresentationInterval = PresentInterval.Immediate; par.Windowed = true; par.SwapEffect = SharpDX.Direct3D9.SwapEffect.Discard; par.PresentationInterval = PresentInterval.Immediate; par.AutoDepthStencilFormat = SharpDX.Direct3D9.Format.D16; par.EnableAutoDepthStencil = true; par.BackBufferFormat = SharpDX.Direct3D9.Format.X8R8G8B8; // firsthandle is the handle of first rendering window D3DDev = new SharpDX.Direct3D9.Device(new Direct3D(), 0, DeviceType.Hardware, firsthandle, CreateFlags.SoftwareVertexProcessing, par); Rendering window initialization: if (parent.D3DDev.SwapChainCount == 0) { SC = parent.D3DDev.GetSwapChain(0); } else { PresentParameters pp = new PresentParameters(); pp.Windowed = true; pp.SwapEffect = SharpDX.Direct3D9.SwapEffect.Discard; pp.BackBufferFormat = SharpDX.Direct3D9.Format.X8R8G8B8; pp.EnableAutoDepthStencil = true; pp.AutoDepthStencilFormat = SharpDX.Direct3D9.Format.D16; pp.PresentationInterval = PresentInterval.Immediate; SC = new SharpDX.Direct3D9.SwapChain(parent.D3DDev, pp); } Code for drawing loop: SharpDX.Direct3D9.Surface bb = SC.GetBackBuffer(0); Parent.D3DDev.SetRenderTarget(0, bb); Parent.D3DDev.Clear(ClearFlags.Target, Color.Black, 1f, 0); SC.Present(Present.None, new SharpDX.Rectangle(), new SharpDX.Rectangle(), HWND); bb.Dispose(); C++ DirectX9/Win32 API test with multiple swapchains and one device code is here: http://pastebin.com/tjnRvATJ It's a modified version from Kevin Harris's nice example code.

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• Very simple, terse and easy GUI programming “frameworks”

  - by jetxee

  Please list GUI programming libraries, toolkits, frameworks which allow to write GUI apps quickly. I mean in such a way, that GUI is described entirely in a human-readable (and human-writable) plain text file (code) code is terse (1 or 2 lines of code per widget/event pair), suitable for scripting structure and operation of the GUI is evident from the code (nesting of widgets and flow of events) details about how to build the GUI are hidden (things like mainloop, attaching event listeners, etc.) auto-layouts are supported (vboxes, hboxes, etc.) As answers suggest, this may be defined as declarative GUI programming, but it is not necessarily such. Any approach is OK if it works, is easy to use and terse. There are some GUI libraries/toolkits like this. They are listed below. Please extend the list if you see a qualifying toolkit missing. Indicate if the project is crossplatform, mature, active, and give an example if possible. Please use this wiki to discuss only Open Source projects. This is the list so far (in alphabetical order): Fudgets Fudgets is a Haskell library. Platform: Unix. Status: Experimental, but still maintained. An example: import Fudgets main = fudlogue (shellF "Hello" (labelF "Hello, world!" >+< quitButtonF)) GNUstep Renaissance Renaissance allows to describe GUI in simple XML. Platforms: OSX/GNUstep. Status: part of GNUstep. An example below: <window title="Example"> <vbox> <label font="big"> Click the button below to quit the application </label> <button title="Quit" action="terminate:"/> </vbox> </window> HTML HTML-based GUI (HTML + JS). Crossplatform, mature. Can be used entirely on the client side. Looking for a nice “helloworld” example. JavaFX JavaFX is usable for standalone (desktop) apps as well as for web applications. Not completely crossplatform, not yet completely open source. Status: 1.0 release. An example: Frame { content: Button { text: "Press Me" action: operation() { System.out.println("You pressed me"); } } visible: true } Screenshot is needed. Phooey Phooey is another Haskell library. Crossplatform (wxWidgets), HTML+JS backend planned. Mature and active. An example (a little more than a helloworld): ui1 :: UI () ui1 = title "Shopping List" $ do a <- title "apples" $ islider (0,10) 3 b <- title "bananas" $ islider (0,10) 7 title "total" $ showDisplay (liftA2 (+) a b) PythonCard PythonCard describes GUI in a Python dictionary. Crossplatform (wxWidgets). Some apps use it, but the project seems stalled. There is an active fork. I skip PythonCard example because it is too verbose for the contest. Shoes Shoes for Ruby. Platforms: Win/OSX/GTK+. Status: Young but active. A minimal app looks like this: Shoes.app { @push = button "Push me" @note = para "Nothing pushed so far" @push.click { @note.replace "Aha! Click!" } } Tcl/Tk Tcl/Tk. Crossplatform (its own widget set). Mature (probably even dated) and active. An example: #!/usr/bin/env wish button .hello -text "Hello, World!" -command { exit } pack .hello tkwait window . tekUI tekUI for Lua (and C). Platforms: X11, DirectFB. Status: Alpha (usable, but API still evolves). An example: #/usr/bin/env lua ui = require "tek.ui" ui.Application:new { Children = { ui.Window:new { Title = "Hello", Children = { ui.Text:new { Text = "_Hello, World!", Style = "button", Mode = "button", }, }, }, }, }:run() Treethon Treethon for Python. It describes GUI in a YAML file (Python in a YAML tree). Platform: GTK+. Status: work in proress. A simple app looks like this: _import: gtk view: gtk.Window() add: - view: gtk.Button('Hello World') on clicked: print view.get_label() Yet unnamed Python library by Richard Jones: This one is not released yet. The idea is to use Python context managers (with keyword) to structure GUI code. See Richard Jones' blog for details. with gui.vertical: text = gui.label('hello!') items = gui.selection(['one', 'two', 'three']) with gui.button('click me!'): def on_click(): text.value = items.value text.foreground = red XUL XUL + Javascript may be used to create stand-alone desktop apps with XULRunner as well as Mozilla extensions. Mature, open source, crossplatform. <?xml version="1.0"?> <?xml-stylesheet href="chrome://global/skin/" type="text/css"?> <window id="main" title="My App" width="300" height="300" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"> <caption label="Hello World"/> </window> Thank your for contributions!

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• OpenGL render vs. own Phong Illumination Implementation

  - by Myx

  Hello: I have implemented a Phong Illumination Scheme using a camera that's centered at (0,0,0) and looking directly at the sphere primitive. The following are the relevant contents of the scene file that is used to view the scene using OpenGL as well as to render the scene using my own implementation: ambient 0 1 0 dir_light 1 1 1 -3 -4 -5 # A red sphere with 0.5 green ambiance, centered at (0,0,0) with radius 1 material 0 0.5 0 1 0 0 1 0 0 0 0 0 0 0 0 10 1 0 sphere 0 0 0 0 1 The resulting image produced by OpenGL. The image that my rendering application produces. As you can see, there are various differences between the two: The specular highlight on my image is smaller than the one in OpenGL. The diffuse surface seems to not diffuse in the correct way, resulting in the yellow region to be unneccessarily large in my image, whereas in OpenGL there's a nice dark green region closer to the bottom of the sphere The color produced by OpenGL is much darker than the one in my image. Those are the most prominent three differences that I see. The following is my implementation of the Phong illumination: R3Rgb Phong(R3Scene *scene, R3Ray *ray, R3Intersection *intersection) { R3Rgb radiance; if(intersection->hit == 0) { radiance = scene->background; return radiance; } R3Vector normal = intersection->normal; R3Rgb Kd = intersection->node->material->kd; R3Rgb Ks = intersection->node->material->ks; // obtain ambient term R3Rgb intensity_ambient = intersection->node->material->ka*scene->ambient; // obtain emissive term R3Rgb intensity_emission = intersection->node->material->emission; // for each light in the scene, obtain calculate the diffuse and specular terms R3Rgb intensity_diffuse(0,0,0,1); R3Rgb intensity_specular(0,0,0,1); for(unsigned int i = 0; i < scene->lights.size(); i++) { R3Light *light = scene->Light(i); R3Rgb light_color = LightIntensity(scene->Light(i), intersection->position); R3Vector light_vector = -LightDirection(scene->Light(i), intersection->position); // calculate diffuse reflection intensity_diffuse += Kd*normal.Dot(light_vector)*light_color; // calculate specular reflection R3Vector reflection_vector = 2.*normal.Dot(light_vector)*normal-light_vector; reflection_vector.Normalize(); R3Vector viewing_vector = ray->Start() - intersection->position; viewing_vector.Normalize(); double n = intersection->node->material->shininess; intensity_specular += Ks*pow(max(0.,viewing_vector.Dot(reflection_vector)),n)*light_color; } radiance = intensity_emission+intensity_ambient+intensity_diffuse+intensity_specular; return radiance; } Here are the related LightIntensity(...) and LightDirection(...) functions: R3Vector LightDirection(R3Light *light, R3Point position) { R3Vector light_direction; switch(light->type) { case R3_DIRECTIONAL_LIGHT: light_direction = light->direction; break; case R3_POINT_LIGHT: light_direction = position-light->position; break; case R3_SPOT_LIGHT: light_direction = position-light->position; break; } light_direction.Normalize(); return light_direction; } R3Rgb LightIntensity(R3Light *light, R3Point position) { R3Rgb light_intensity; double distance; double denominator; if(light->type != R3_DIRECTIONAL_LIGHT) { distance = (position-light->position).Length(); denominator = light->constant_attenuation + light->linear_attenuation*distance + light->quadratic_attenuation*distance*distance; } switch(light->type) { case R3_DIRECTIONAL_LIGHT: light_intensity = light->color; break; case R3_POINT_LIGHT: light_intensity = light->color/denominator; break; case R3_SPOT_LIGHT: R3Vector from_light_to_point = position - light->position; light_intensity = light->color*( pow(light->direction.Dot(from_light_to_point), light->angle_attenuation)); break; } return light_intensity; } I would greatly appreciate any suggestions as to any implementation errors that are apparent. I am wondering if the differences could be occurring simply because of the gamma values used for display by OpenGL and the default gamma value for my display. I also know that OpenGL (or at least tha parts that I was provided) can't cast shadows on objects. Not that this is relevant for the point in question, but it just leads me to wonder if it's simply display and capability differences between OpenGL and what I am trying to do. Thank you for your help.

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• How to associate Wi-Fi beacon info with a virtual "location"?

  - by leander

  We have a piece of embedded hardware that will sense 802.11 beacons, and we're using this to make a map of currently visible bssid -> signalStrength. Given this map, we would like to make a determination: Is this likely to be a location I have been to before? If so, what is its ID? If not, I should remember this location: generate a new ID. Now what should I store (and how should I store it) to make future determinations easier? This is for an augmented-reality app/game. We will be using it to associate particular characters and events with "locations". The device does not have internet or cellular access, so using a geolocation service is out of consideration for the time being. (We don't really need to know where we are in reality, just be able to determine if we return there.) It isn't crucial that it be extremely accurate, but it would be nice if it was tolerant to signal strength changes or the occasional missing beacon. It should be usable in relatively low numbers of access points (e.g. rural house with one wireless router) or many (wandering around a dense metropolis). In the case of a city, it should change location every few minutes of walking (continuously-overlapping signals make this a bit more tricky in naive code). A reasonable number of false positives (match a location when we aren't actually there) is acceptable. The wrong character/event showing up just adds a bit of variety. False negatives (no location match) are a bit more troublesome: this will tend to add a better-matching new location to the saved locations, masking the old one. While we will have additional logic to ensure locations that the device hasn't seen in a while will "orphan" any associated characters or events (if e.g. you move to a different country), we'd prefer not to mask and eventually orphan locations you do visit regularly. Some technical complications: signalStrength is returned as 1-4; presumably it's related to dB, but we are not sure exactly how; in my experiments it tends to stick to either 1 or 4, but occasionally we see numbers in between. (Tech docs on the hardware are sparse.) The device completes a scan of one-quarter of the channel space every second; so it takes about 4-5 seconds to get a complete picture of what's around. The list isn't always complete. (We are making strides to fix this using some slight sampling period randomization, as recommended by the library docs. We're also investigating ways to increase the number of scans without killing our performance; the hardware/libs are poorly behaved when it comes to saturating the bus.) We have only kilobytes to store our history. We have a "working" impl now, but it is relatively naive, and flaky in the face of real-world Wi-Fi behavior. Rough pseudocode: // recordLocation() -- only store strength 4 locations m_savedLocations[g_nextId++] = filterForStrengthGE( m_currentAPs, 4 ); // determineLocation() bestPoints = -inf; foreach ( oldLoc in m_savedLocations ) { points = 0.0; foreach ( ap in m_currentAPs ) { if ( oldLoc.has( ap ) ) { switch ( ap.signalStrength ) { case 3: points += 1.0; break; case 4: points += 2.0; break; } } } points /= oldLoc.numAPs; if ( points > bestPoints ) { bestLoc = oldLoc; bestPoints = points; } } if ( bestLoc && bestPoints > 1.0 ) { if ( bestPoints >= (2.0 - epsilon) ) { // near-perfect match. // update location with any new high-strength APs that have appeared bestLoc.addAPs( filterForStrengthGE( m_currentAPs, 4 ) ); } return bestLoc; } else { return NO_MATCH; } We record a location currently only when we have NO_MATCH and the app determines it's time for a new event. (The "near-perfect match" code above would appear to make it harder to match in the future... It's mostly to keep new powerful APs from being associated with other locations, but you'd think we'd need something to counter this if e.g. an AP doesn't show up in the next 10 times I match a location.) I have a feeling that we're missing some things from set theory or graph theory that would assist in grouping/classification of this data, and perhaps providing a better "confidence level" on matches, and better robustness against missed beacons, signal strength changes, and the like. Also it would be useful to have a good method for mutating locations over time. Any useful resources out there for this sort of thing? Simple and/or robust approaches we're missing?

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• Access Violation

  - by Justin

  I've been learning how to NOP functions in C++ or even C but there are very few tutorials online about it. I've been googling for the past few hours now and I'm just stuck. Here is my code. #include <iostream> #include <windows.h> #include <tlhelp32.h> using namespace std; //#define NOP 0x90 byte NOP[] = {0x90}; void enableDebugPrivileges() { HANDLE hcurrent=GetCurrentProcess(); HANDLE hToken; BOOL bret=OpenProcessToken(hcurrent,40,&hToken); LUID luid; bret=LookupPrivilegeValue(NULL,"SeDebugPrivilege",&luid); TOKEN_PRIVILEGES NewState,PreviousState; DWORD ReturnLength; NewState.PrivilegeCount =1; NewState.Privileges[0].Luid =luid; NewState.Privileges[0].Attributes=2; AdjustTokenPrivileges(hToken,FALSE,&NewState,28,&PreviousState,&ReturnLength); } DWORD GetProcId(char* ProcName) { PROCESSENTRY32 pe32; HANDLE hSnapshot = NULL; pe32.dwSize = sizeof( PROCESSENTRY32 ); hSnapshot = CreateToolhelp32Snapshot( TH32CS_SNAPPROCESS, 0 ); if( Process32First( hSnapshot, &pe32 ) ) { do{ if( strcmp( pe32.szExeFile, ProcName ) == 0 ) break; }while( Process32Next( hSnapshot, &pe32 ) ); } if( hSnapshot != INVALID_HANDLE_VALUE ) CloseHandle( hSnapshot ); return pe32.th32ProcessID; } void WriteMem(DWORD Address, void* Value, size_t Size) { DWORD Protect = NULL; VirtualProtect((LPVOID)Address, 3, PAGE_READWRITE, &Protect); memcpy((void*)Address, Value, 3); VirtualProtect((LPVOID)Address, 3, Protect, &Protect); } void nop_(PVOID address, int bytes){ DWORD d, ds; VirtualProtect(address, bytes, PAGE_EXECUTE_READWRITE, &d); memset(address, 144, bytes); VirtualProtect(address,bytes,d,&ds); } void MemCopy(HANDLE pHandle, void* Dest, const void* Src, int Len) { DWORD OldProtect; DWORD OldProtect2; VirtualProtect(Dest, Len, PAGE_EXECUTE_READWRITE, &OldProtect); memcpy(Dest, Src, Len); VirtualProtect(Dest, Len, OldProtect, &OldProtect2); FlushInstructionCache(pHandle, Dest, Len); } int main() { enableDebugPrivileges(); DWORD pid; HANDLE phandle; // Obtain the process ID pid = GetProcId("gr.exe"); if(GetLastError()) { cout << "Error_PID_: " << GetLastError() << endl; system("pause"); return -1; } // Obtain the process handle phandle = OpenProcess(PROCESS_ALL_ACCESS,0,pid); if(GetLastError()) { cout << "Error_HANDLE_: " << GetLastError() << endl; system("pause"); return -1; } // Debug info, 0 = bad cout <<"pid : " << pid << endl; cout <<"HANDLE: " << phandle << endl << endl; system("pause"); // Change value to short iValue = -1; int choice = 0; BYTE * bGodMode = (BYTE *) (0x409A7E); // Lives Address bool hack = true; while(hack) { system("cls"); cout << "What hack?\n0. Exit\n1. Lives\n\n!> "; cin >> choice; switch(choice) { case 0: { hack=false; break; } case 1: // Modify Time cout << "God Mode On\n!> "; // cin >> iValue; // nop_((PVOID)(0x409A7E), 3); // MemCopy(phandle, (PVOID)0x409A7E, &NOP, 1); WriteMem((DWORD)(0x00409A7E), (void*)NOP, sizeof NOP); if(GetLastError()) { cout << "Error: " << GetLastError() << endl; system("pause"); } break; default: cout << "ERROR!\n"; break; } Sleep(100); } system("pause"); return 0; } This is suppose to NOP the DEC function that is 3 bytes long preventing me from losing lives. However each time I try it, it crashes the hack and says I had a access violation. I tried to look up the reasons and most of them dealt with with the size of the location I'm writing to and what I'm copying from. Otherwise, I have absolutely no idea. Any help would be nice. The game is GunRoar and the base address "0x409A7E" is where the DEC function is.

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• Ajax, Multiple Attachments and Paperclip question.

  - by dustmoo

  Alright everyone this is a bit of a complicated setup so if I need to clarify the question just let me know. I have a model: class IconSet < ActiveRecord::Base has_many :icon_graphics end This Model has many icongraphics: class IconGraphic < ActiveRecord::Base belongs_to :icon_set has_attached_file :icon has_attached_file :flagged end As you can see, IconGraphic has two attached files, basically two different versions of the icon that I want to load. Now, this setup is working okay if I edit the icongraphic's individually, however, for ease of use, I have all the icon graphics editable under the IconSet. When you edit the icon set the form loads a partial for the icongraphics: <% form_for @icon_set, :html => {:class => 'nice', :multipart => true} do |f| %> <fieldset> <%= f.error_messages %> <p> <%= f.label :name %> <%= f.text_field :name, :class => "text_input" %> </p> <!-- Loaded Partial for icongraphics --> <div id="icon_graphics"> <%= render :partial => 'icon_graphic', :collection => @icon_set.icon_graphics %> </div> <div class="add_link"> <%= link_to_function "Add an Icon" do |page| page.insert_html :bottom, :icon_graphics, :partial => 'icon_graphic', :object => IconGraphic.new end %> </div> <p><%= f.submit "Submit" %></p> </fieldset> <% end %> This is based largely off of Ryan's Complex Forms Railscast. The partial loads the file_field forms: <div class="icon_graphic"> <% fields_for "icon_set[icon_graphic_attributes][]", icon_graphic do |icon_form|-%> <%- if icon_graphic.new_record? -%> <strong>Upload Icon: </strong><%= icon_form.file_field :icon, :index => nil %><br/> <strong>Upload Flagged Icon: </strong><%= icon_form.file_field :flagged, :index => nil %> <%= link_to_function image_tag('remove_16.png'), "this.up('.icon_graphic').remove()"%><br/> <% else -%> <%= image_tag icon_graphic.icon.url %><br/> <strong>Replace <%= icon_graphic.icon_file_name %>: </strong><%= icon_form.file_field :icon, :index => nil %><br /> <% if icon_graphic.flagged_file_name.blank? -%> <strong>Upload Flagged Icon: </strong><%= icon_form.file_field :flagged, :index => nil %> <% else -%> <strong>Replace <%= icon_graphic.flagged_file_name %>: </strong><%= icon_form.file_field :flagged, :index => nil %> <%= icon_form.hidden_field :flagged, :index => nil %> <% end -%> <%= link_to_function image_tag('remove_16.png'), "mark_for_destroy(this, '.icon_graphic')"%><br/> <%= icon_form.hidden_field :id, :index => nil %> <%= icon_form.hidden_field :icon, :index => nil %> <%= icon_form.hidden_field :should_destroy, :index => nil, :class => 'should_destroy' %> <br/><br/> <%- end -%> <% end -%> </div> Now, this is looking fine when I add new icons, and fill both fields. However, if I edit the IconSet after the fact, and perhaps try to replace the icon with a new one, or if I uploaded only one of the set and try to add the second attachment, paperclip doesn't put the attachments with the right IconGraphic Model. It seems that even though I have the IconGraphic ID in each partial, <%= icon_form.hidden_field :id, :index => nil %> it seems that paperclip either creates a new IconGraphic or attaches it to the wrong one. This all happens when you save the IconSet, which is setup to save the IconGraphic attributes. I know this is complicated.. I may just have to go to editing each icon individually, but if anyone can help, I would appreciate it.

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• $_GET loading content before head tag instead of in specified div.

  - by s32ialx

  NOT EDITING BELOW BUT THANKS TO SOME REALLY NICE PEOPLE I CAN'T POST AN IMAGE ANYMORE BECAUSE I HAD a 15 Rep but NOW ONLY A 5 becuase my question wasn't what they wanted help with they gave me a neg rep. The problem is that the content loads it displays UNDER the div i placed #CONTENT# inside so the styles are being ignored and it's posting #CONTENT# outside the divs at positions 0,0 any suggestions? Found out whats happening by using "View Source" seems that it's putting all of the #CONTENT#, content that's being loaded in front of the <head> tag. Like this <doctype...> <div class="home"> \ blah blah #CONTENT# bot being loaded in correct specified area </div> / <head> <script src=""></script> </head> <body> <div class="header"></div> <div class="contents"> #CONTENT# < where content SHOULD load </div> <div class="footer"></div> </body> so anyone got a fix? OK so a better description I'll add relevant screen-shots Whats happening is /* file.class.php */ <?php $file = new file(); class file{ var $path = "templates/clean"; var $ext = "tpl"; function loadfile($filename){ return file_get_contents($this->path . "/" . $filename . "." . $this->ext); } function setcontent($content,$newcontent,$vartoreplace='#CONTENT#'){ $val = str_replace($vartoreplace,$newcontent,$content); return $val; } function p($content) { $v = $content; $v = str_replace('#CONTENT#','',$v); print $v; } } if(!isset($_GET['page'])){ // if not, lets load our index page(you can change home.php to whatever you want: include("main.txt"); // else $_GET['page'] was set so lets do stuff: } else { // lets first check if the file exists: if(file_exists($_GET['page'].'.txt')){ // and lets include that then: include($_GET['page'].'.txt'); // sorry mate, could not find it: } else { echo 'Sorry, could not find <strong>' . $_GET['page'] .'.txt</strong>'; } } ?> is calling for a file_get_contents at the bottom which I use in /* index.php */ <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <?php include('classes/file.class.php'); // load the templates $header = $file->loadfile('header'); $body = $file->loadfile('body'); $footer = $file->loadfile('footer'); // fill body.tpl #CONTENT# slot with $content $body = $file->setcontent($body, $content); // cleanup and output the full page $file->p($header . $body . $footer); ?> and loads into /* body.tpl */ <div id="bodys"> <div id="bodt"></div> <div id="bodm"> <div id="contents"> #CONTENT# </div> </div> <div id="bodb"></div> </div> but the issue is as follows the $content loads properly img tags etc <h2> tags etc but CSS styling is TOTALY ignored for position width z-index etc. and as follows here's the screen-shot My Firefox Showing The Problem In Action REPOSTED DUE TO PEOPLE NOT HELPING AND JUST BEING ARROGANT AND GIVING NEGATIVE VOTES and not even saying a word. DO NOT COMMENT UNLESS YOU PLAN TO HELP god I'm a beginner and with you people giving me bad reviews this won't make me help you out when the chance comes.

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• XML parsing and transforming (XSLT or otherwise)

  - by observ

  I have several xml files that are formated this way: <ROOT> <OBJECT> <identity> <id>123</id> </identity> <child2 attr = "aa">32</child2> <child3> <childOfChild3 att1="aaa" att2="bbb" att3="CCC">LN</childOfChild3> </child3> <child4> <child5> <child6>3ddf</child6> <child7> <childOfChild7 att31="RR">1231</childOfChild7> </child7> </child5> </child4> </OBJECT> <OBJECT> <identity> <id>124</id> </identity> <child2 attr = "bb">212</child2> <child3> <childOfChild3 att1="ee" att2="ccc" att3="EREA">OP</childOfChild3> </child3> <child4> <child5> <child6>213r</child6> <child7> <childOfChild7 att31="EE">1233</childOfChild7> </child7> </child5> </child4> </OBJECT> </ROOT> How can i format it this way?: <ROOT> <OBJECT> <id>123</id> <child2>32</child2> <attr>aa</attr> <child3></child3> <childOfChild3>LN</childOfChild3> <att1>aaa</att1> <att2>bbb</att2> <att3>CCC</att3> <child4></child4> <child5></child5> <child6>3ddf</child6> <child7></child7> <childOfChild7>1231</childOfChild7> <att31>RR</att31> </OBJECT> <OBJECT> <id>124</id> <child2>212</child2> <attr>bb</attr> <child3></child3> <childOfChild3>LN</childOfChild3> <att1>ee</att1> <att2>ccc</att2> <att3>EREA</att3> <child4></child4> <child5></child5> <child6>213r</child6> <child7></child7> <childOfChild7>1233</childOfChild7> <att31>EE</att31> </OBJECT> </ROOT> I know some C# so maybe a parser there? or some generic xslt? The xml files are some data received from a client, so i can't control the way they are sending it to me. L.E. Basically when i am trying to test this data in excel (for example i want to make sure that the attribute of childOfChild7 corresponds to the correct identity id) i am getting a lot of blank spaces. If i am importing in access to get only the data i want out, i have to do a thousands subqueries to get them all in a nice table. Basically i just want to see for one Object all its data (one object - One row) and then just delete/hide the columns i don't need.

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• asp .net MVC 2.0 Validation

  - by ANDyW

  Hi I’m trying to do some validation in asp .net MVC 2.0 for my application. I want to have some nice client side validation. Validation should be done most time on model side with DataAnnotations with custom attributes( like CompareTo, StringLenght, MinPasswordLenght (from Membership.MinimumumpassworkdLenght value). For that purpose I tried to use xval with jquery.validation. Some specific thing is that most of forms will be working with ajax and most problems are when I want to validate form with ajax. Here is link for sample project http://www.sendspace.com/file/m9gl54 . I got two forms as controls ValidFormControl1.ascx, ValidFormControl2.ascx <% using (Ajax.BeginForm("CreateValidForm", "Test", new AjaxOptions { HttpMethod = "Post" })) {%> <div id="validationSummary1"> <%= Html.ValidationSummary(true)%> </div> <fieldset> <legend>Fields</legend> <div class="editor-label"> <%= Html.LabelFor(model => model.Name)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Name)%> <%= Html.ValidationMessageFor(model => model.Name)%> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Email)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Email)%> <%= Html.ValidationMessageFor(model => model.Email)%> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Password)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Password)%> <%= Html.ValidationMessageFor(model => model.Password)%> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.ConfirmPassword)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.ConfirmPassword)%> <%= Html.ValidationMessageFor(model => model.ConfirmPassword)%> </div> <p> <input type="submit" value="Create" /> </p> </fieldset> <% } %> <%= Html.ClientSideValidation<ValidModel>() .UseValidationSummary("validationSummary1", "Please fix the following problems:") %> Both look same the difference is only validation summaryID (validationSummary1, validationSummary2). Both controls are rendered on one page : Form2 <%Html.RenderPartial("~/Views/Test/ValidFormControl2.ascx", null); %> Form1 <%Html.RenderPartial("~/Views/Test/ValidFormControl.ascx", null); %> Validation property First problem, when we have two controls with same type to validate it don’t work becosue html elements are rendered by field name ( so we have two element with same name “Password” ). Only first form will be validated by client side. The worst thing is that even if we have different types and their fields name is same validation won’t work too ( this thing is what I need to repair it will be stupid to name some unique properites for validation ). Is there any solution for this ? Custom attributes validation Next thing custom attributes validation ( All those error are when I use Ajax for on normal form validation is working without problem. ): CompareTo - Simple compare to that is done in mvc template for account model ( class attribute saying with two property will be compared ) , and it wasn’t show on page. To do it I created own CachingRulesProvider with compareRule and my Attribute. Maybe there is more easy way to do it? StringLenght with minimum and maximum value, I won’t describe how I done it but is there any easy whey to do it? Validation summary When I have two two control on page all summary validation information goes to first control validation summary element, even xval generated script say that elementID are different for summary. Any one know how to repair it? Validation Information Is there any option to turn on messages on place where is Html.ValidationMessageFor(model = model.ConfirmPassword). Becsoue for me it isn’t show up. I would like to have summary and near field information too not only red border. Any one know how to do it? Ajax submit Anyone know how to do easy without massive code in javascript to do submit via javascript. This will be used to change input submit to href element (a). Both look same the difference is only validation summaryID

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• Yet another C# Deadlock Debugging Question

  - by Roo

  Hi All, I have a multi-threaded application build in C# using VS2010 Professional. It's quite a large application and we've experienced the classing GUI cross-threading and deadlock issues before, but in the past month we've noticed the appears to lock up when left idle for around 20-30 minutes. The application is irresponsive and although it will repaint itself when other windows are dragged in front of the application and over it, the GUI still appears to be locked... interstingly (unlike if the GUI thread is being used for a considerable amount of time) the Close, Maximise and minimise buttons are also irresponsive and when clicked the little (Not Responding...) text is not displayed in the title of the application i.e. Windows still seems to think it's running fine. If I break/pause the application using the debugger, and view the threads that are running. There are 3 threads of our managed code that are running, and a few other worker threads whom the source code cannot be displayed for. The 3 threads that run are: The main/GUI thread A thread that loops indefinitely A thread that loops indefinitely If I step into threads 2 and 3, they appear to be looping correctly. They do not share locks (even with the main GUI thread) and they are not using the GUI thread at all. When stepping into the main/GUI thread however, it's broken on Application.Run... This problem screams deadlock to me, but what I don't understand is if it's deadlock, why can't I see the line of code the main/GUI thread is hanging on? Any help will be greatly appreciated! Let me know if you need more information... Cheers, Roo -----------------------------------------------------SOLUTION-------------------------------------------------- Okay, so the problem is now solved. Thanks to everyone for their suggestions! Much appreciated! I've marked the answer that solved my initial problem of determining where on the main/UI thread the application hangs (I handn't turned off the "Enable Just My Code" option). The overall issue I was experiencing was indeed Deadlock, however. After obtaining the call-stack and popping the top half of it into Google I came across this which explains exactly what I was experiencing... http://timl.net/ This references a lovely guide to debugging the issue... http://www.aaronlerch.com/blog/2008/12/15/debugging-ui/ This identified a control I was constructing off the GUI thread. I did know this, however, and was marshalling calls correctly, but what I didn't realise was that behind the scenes this Control was subscribing to an event or set of events that are triggered when e.g. a Windows session is unlocked or the screensaver exits. These calls are always made on the main/UI thread and were blocking when it saw the call was made on the incorrect thread. Kim explains in more detail here... http://krgreenlee.blogspot.com/2007/09/onuserpreferencechanged-hang.html In the end I found an alternative solution which did not require this Control off the main/UI thread. That appears to have solved the problem and the application no longer hangs. I hope this helps anyone who's confronted by a similar problem. Thanks again to everyone on here who helped! (and indirectly, the delightful bloggers I've referenced above!) Roo -----------------------------------------------------SOLUTION II-------------------------------------------------- Aren't threading issues delightful...you think you've solved it, and a month down the line it pops back up again. I still believe the solution above resolved an issue that would cause simillar behaviour, but we encountered the problem again. As we spent a while debugging this, I thought I'd update this question with our (hopefully) final solution: The problem appears to have been a bug in the Infragistics components in the WinForms 2010.1 release (no hot fixes). We had been running from around the time the freeze issue appeared (but had also added a bunch of other stuff too). After upgrading to WinForms 2010.3, we've yet to reproduce the issue (deja vu). See my question here for a bit more information: 'http://stackoverflow.com/questions/4077822/net-4-0-and-the-dreaded-onuserpreferencechanged-hang'. Hans has given a nice summary of the general issue. I hope this adds a little to the suggestions/information surrounding the nutorious OnUserPreferenceChanged Hang (or whatever you'd like to call it). Cheers, Roo

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• how to click on a button in python

  - by Ciobanu Alexandru

  Trying to build some bot for clicking "skip-ad" button on a page. So far, i manage to use Mechanize to load a web-driver browser and to connect to some page but Mechanize module do not support js directly so now i need something like Selenium if i understand correct. I am also a beginner in programming so please be specific. How can i use Selenium or if there is any other solution, please explain details. This is the inner html code for the button: <a id="skip-ad" class="btn btn-inverse" onclick="open_url('http://imgur.com/gallery/tDK9V68', 'go'); return false;" style="font-weight: bold; " target="_blank" href="http://imgur.com/gallery/tDK9V68"> … </a> And this is my source so far: #!/usr/bin/python # FILENAME: test.py import mechanize import os, time from random import choice, randrange prox_list = [] #list of common UAS to apply to each connection attempt to impersonate browsers user_agent_strings = [ 'Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1468.0 Safari/537.36', 'Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.1) Gecko/2008071615 Fedora/3.0.1-1.fc9 Firefox/3.0.1', 'Opera/9.80 (Windows NT 6.0) Presto/2.12.388 Version/12.14', 'Opera/9.80 (Macintosh; Intel Mac OS X 10.6.8; U; fr) Presto/2.9.168 Version/11.52', 'Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:23.0) Gecko/20131011 Firefox/23.0', 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; Media Center PC 6.0; InfoPath.3; MS-RTC LM 8; Zune 4.7', 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0; .NET CLR 2.0.50727; SLCC2; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; Zune 4.0; Tablet PC 2.0; InfoPath.3; .NET4.0C; .NET4.0E)', 'Mozilla/5.0 (compatible; MSIE 10.6; Windows NT 6.1; Trident/5.0; InfoPath.2; SLCC1; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET CLR 2.0.50727) 3gpp-gba UNTRUSTED/1.0', 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.0; Trident/5.0; chromeframe/11.0.696.57)', 'Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; InfoPath.1; SV1; .NET CLR 3.8.36217; WOW64; en-US)', 'Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; GTB7.4; InfoPath.2; SV1; .NET CLR 3.3.69573; WOW64; en-US)' ] def load_proxy_list(target): #loads and parses the proxy list file = open(target, 'r') count = 0 for line in file: prox_list.append(line) count += 1 print "Loaded " + str(count) + " proxies!" load_proxy_list('proxies.txt') #for i in range(1,(len(prox_list) - 1)): # depreceated for overloading for i in range(1,30): br = mechanize.Browser() #pick a random UAS to add some extra cover to the bot br.addheaders = [('User-agent', choice(user_agent_strings))] print "----------------------------------------------------" #This is bad internet ethics br.set_handle_robots(False) #choose a proxy proxy = choice(prox_list) br.set_proxies({"http": proxy}) br.set_debug_http(True) try: print "Trying connection with: " + str(proxy) #currently using: BTC CoinURL - Grooveshark Broadcast br.open("http://cur.lv/4czwj") print "Opened successfully!" #act like a nice little drone and view the ads sleep_time_on_link = randrange(17.0,34.0) time.sleep(sleep_time_on_link) except mechanize.HTTPError, e: print "Oops Request threw " + str(e.code) #future versions will handle codes properly, 404 most likely means # the ad-linker has noticed bot-traffic and removed the link # or the used proxy is terrible. We will either geo-locate # proxies beforehand and pick good hosts, or ditch the link # which is worse case scenario, account is closed because of botting except mechanize.URLError, e: print "Oops! Request was refused, blacklisting proxy!" + str(e) prox_list.remove(proxy) del br #close browser entirely #wait between 5-30 seconds like a good little human sleep_time = randrange(5.0, 30.0) print "Waiting for %.1f seconds like a good bot." % (sleep_time) time.sleep(sleep_time)

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• Matplotlib plotting non uniform data in 3D surface

  - by Raj Tendulkar

  I have a simple code to plot the points in 3D for Matplotlib as below - from mpl_toolkits.mplot3d import axes3d import matplotlib.pyplot as plt import numpy as np from numpy import genfromtxt import csv fig = plt.figure() ax = fig.add_subplot(111, projection='3d') my_data = genfromtxt('points1.csv', delimiter=',') points1X = my_data[:,0] points1Y = my_data[:,1] points1Z = my_data[:,2] ## I remove the header of the CSV File. points1X = np.delete(points1X, 0) points1Y = np.delete(points1Y, 0) points1Z = np.delete(points1Z, 0) # Convert the array to 1D array points1X = np.reshape(points1X,points1X.size) points1Y = np.reshape(points1Y,points1Y.size) points1Z = np.reshape(points1Z,points1Z.size) my_data = genfromtxt('points2.csv', delimiter=',') points2X = my_data[:,0] points2Y = my_data[:,1] points2Z = my_data[:,2] ## I remove the header of the CSV File. points2X = np.delete(points2X, 0) points2Y = np.delete(points2Y, 0) points2Z = np.delete(points2Z, 0) # Convert the array to 1D array points2X = np.reshape(points2X,points2X.size) points2Y = np.reshape(points2Y,points2Y.size) points2Z = np.reshape(points2Z,points2Z.size) ax.plot(points1X, points1Y, points1Z, 'd', markersize=8, markerfacecolor='red', label='points1') ax.plot(points2X, points2Y, points2Z, 'd', markersize=8, markerfacecolor='blue', label='points2') plt.show() My problem is that I tried to make a decent surface plot out of these data points that I have. I already tried to use ax.plot_surface() function to make it look nice. For this I eliminated some points, and recalculated the matrix kind of input needed by this function. However, the graph I generated was far more difficult to interpret and understand. So there might be 2 possibilities: either I am not using the function correctly, or otherwise, the data I am trying to plot is not good for the surface plot. What I was expecting was 3D graph which would have an effect similar to that we have of 3D pie chart. We see that one piece (that which is extracted out) is part of another piece. I was not expecting it to be exactly same like that, but some kind of effect like that. What I would like to ask is: Do you think it will be possible to make such 3D graph? Is there any way better, I could express my data in 3 dimension? Here are the 2 files - points1.csv Dim1,Dim2,Dim3 3,8,1 3,8,2 3,8,3 3,8,4 3,8,5 3,9,1 3,9,2 3,9,3 3,9,4 3,9,5 3,10,1 3,10,2 3,10,3 3,10,4 3,10,5 3,11,1 3,11,2 3,11,3 3,11,4 3,11,5 3,12,1 3,12,2 3,13,1 3,13,2 3,14,1 3,14,2 3,15,1 3,15,2 3,16,1 3,16,2 3,17,1 3,17,2 3,18,1 3,18,2 4,8,1 4,8,2 4,8,3 4,8,4 4,8,5 4,9,1 4,9,2 4,9,3 4,9,4 4,9,5 4,10,1 4,10,2 4,10,3 4,10,4 4,10,5 4,11,1 4,11,2 4,11,3 4,11,4 4,11,5 4,12,1 4,13,1 4,14,1 4,15,1 4,16,1 4,17,1 4,18,1 5,8,1 5,8,2 5,8,3 5,8,4 5,8,5 5,9,1 5,9,2 5,9,3 5,9,4 5,9,5 5,10,1 5,10,2 5,10,3 5,10,4 5,10,5 5,11,1 5,11,2 5,11,3 5,11,4 5,11,5 5,12,1 5,13,1 5,14,1 5,15,1 5,16,1 5,17,1 5,18,1 6,8,1 6,8,2 6,8,3 6,8,4 6,8,5 6,9,1 6,9,2 6,9,3 6,9,4 6,9,5 6,10,1 6,11,1 6,12,1 6,13,1 6,14,1 6,15,1 6,16,1 6,17,1 6,18,1 7,8,1 7,8,2 7,8,3 7,8,4 7,8,5 7,9,1 7,9,2 7,9,3 7,9,4 7,9,5 and points2.csv Dim1,Dim2,Dim3 3,12,3 3,12,4 3,12,5 3,13,3 3,13,4 3,13,5 3,14,3 3,14,4 3,14,5 3,15,3 3,15,4 3,15,5 3,16,3 3,16,4 3,16,5 3,17,3 3,17,4 3,17,5 3,18,3 3,18,4 3,18,5 4,12,2 4,12,3 4,12,4 4,12,5 4,13,2 4,13,3 4,13,4 4,13,5 4,14,2 4,14,3 4,14,4 4,14,5 4,15,2 4,15,3 4,15,4 4,15,5 4,16,2 4,16,3 4,16,4 4,16,5 4,17,2 4,17,3 4,17,4 4,17,5 4,18,2 4,18,3 4,18,4 4,18,5 5,12,2 5,12,3 5,12,4 5,12,5 5,13,2 5,13,3 5,13,4 5,13,5 5,14,2 5,14,3 5,14,4 5,14,5 5,15,2 5,15,3 5,15,4 5,15,5 5,16,2 5,16,3 5,16,4 5,16,5 5,17,2 5,17,3 5,17,4 5,17,5 5,18,2 5,18,3 5,18,4 5,18,5 6,10,2 6,10,3 6,10,4 6,10,5 6,11,2 6,11,3 6,11,4 6,11,5 6,12,2 6,12,3 6,12,4 6,12,5 6,13,2 6,13,3 6,13,4 6,13,5 6,14,2 6,14,3 6,14,4 6,14,5 6,15,2 6,15,3 6,15,4 6,15,5 6,16,2 6,16,3 6,16,4 6,16,5 6,17,2 6,17,3 6,17,4 6,17,5 6,18,2 6,18,3 6,18,4 6,18,5 7,10,1 7,10,2 7,10,3 7,10,4 7,10,5 7,11,1 7,11,2 7,11,3 7,11,4 7,11,5 7,12,1 7,12,2 7,12,3 7,12,4 7,12,5 7,13,1 7,13,2 7,13,3 7,13,4 7,13,5 7,14,1 7,14,2 7,14,3 7,14,4 7,14,5 7,15,1 7,15,2 7,15,3 7,15,4 7,15,5 7,16,1 7,16,2 7,16,3 7,16,4 7,16,5 7,17,1 7,17,2 7,17,3 7,17,4 7,17,5 7,18,1 7,18,2 7,18,3 7,18,4 7,18,5

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• Creating a new plugin for mpld3

  - by sjp14051

  Toward learning how to create a new mpld3 plugin, I took an existing example, LinkedDataPlugin (http://mpld3.github.io/examples/heart_path.html), and modified it slightly by deleting references to lines object. That is, I created the following: class DragPlugin(plugins.PluginBase): JAVASCRIPT = r""" mpld3.register_plugin("drag", DragPlugin); DragPlugin.prototype = Object.create(mpld3.Plugin.prototype); DragPlugin.prototype.constructor = DragPlugin; DragPlugin.prototype.requiredProps = ["idpts", "idpatch"]; DragPlugin.prototype.defaultProps = {} function DragPlugin(fig, props){ mpld3.Plugin.call(this, fig, props); }; DragPlugin.prototype.draw = function(){ var patchobj = mpld3.get_element(this.props.idpatch, this.fig); var ptsobj = mpld3.get_element(this.props.idpts, this.fig); var drag = d3.behavior.drag() .origin(function(d) { return {x:ptsobj.ax.x(d[0]), y:ptsobj.ax.y(d[1])}; }) .on("dragstart", dragstarted) .on("drag", dragged) .on("dragend", dragended); patchobj.path.attr("d", patchobj.datafunc(ptsobj.offsets, patchobj.pathcodes)); patchobj.data = ptsobj.offsets; ptsobj.elements() .data(ptsobj.offsets) .style("cursor", "default") .call(drag); function dragstarted(d) { d3.event.sourceEvent.stopPropagation(); d3.select(this).classed("dragging", true); } function dragged(d, i) { d[0] = ptsobj.ax.x.invert(d3.event.x); d[1] = ptsobj.ax.y.invert(d3.event.y); d3.select(this) .attr("transform", "translate(" + [d3.event.x,d3.event.y] + ")"); patchobj.path.attr("d", patchobj.datafunc(ptsobj.offsets, patchobj.pathcodes)); } function dragended(d, i) { d3.select(this).classed("dragging", false); } } mpld3.register_plugin("drag", DragPlugin); """ def __init__(self, points, patch): print "Points ID : ", utils.get_id(points) self.dict_ = {"type": "drag", "idpts": utils.get_id(points), "idpatch": utils.get_id(patch)} However, when I try to link the plugin to a figure, as in plugins.connect(fig, DragPlugin(points[0], patch)) I get an error, 'module' is not callable, pointing to this line. What does this mean and why doesn't it work? Thanks. I'm adding additional code to show that linking more than one Plugin might be problematic. But this may be entirely due to some silly mistake on my part, or there is a way around it. The following code based on LinkedViewPlugin generates three panels, in which the top and the bottom panel are supposed to be identical. Mouseover in the middle panel was expected to control the display in the top and bottom panels, but updates occur in the bottom panel only. It would be nice to be able to figure out how to reflect the changes in multiple panels. Thanks. import matplotlib import matplotlib.pyplot as plt import numpy as np import mpld3 from mpld3 import plugins, utils class LinkedView(plugins.PluginBase): """A simple plugin showing how multiple axes can be linked""" JAVASCRIPT = """ mpld3.register_plugin("linkedview", LinkedViewPlugin); LinkedViewPlugin.prototype = Object.create(mpld3.Plugin.prototype); LinkedViewPlugin.prototype.constructor = LinkedViewPlugin; LinkedViewPlugin.prototype.requiredProps = ["idpts", "idline", "data"]; LinkedViewPlugin.prototype.defaultProps = {} function LinkedViewPlugin(fig, props){ mpld3.Plugin.call(this, fig, props); }; LinkedViewPlugin.prototype.draw = function(){ var pts = mpld3.get_element(this.props.idpts); var line = mpld3.get_element(this.props.idline); var data = this.props.data; function mouseover(d, i){ line.data = data[i]; line.elements().transition() .attr("d", line.datafunc(line.data)) .style("stroke", this.style.fill); } pts.elements().on("mouseover", mouseover); }; """ def __init__(self, points, line, linedata): if isinstance(points, matplotlib.lines.Line2D): suffix = "pts" else: suffix = None self.dict_ = {"type": "linkedview", "idpts": utils.get_id(points, suffix), "idline": utils.get_id(line), "data": linedata} class LinkedView2(plugins.PluginBase): """A simple plugin showing how multiple axes can be linked""" JAVASCRIPT = """ mpld3.register_plugin("linkedview", LinkedViewPlugin2); LinkedViewPlugin2.prototype = Object.create(mpld3.Plugin.prototype); LinkedViewPlugin2.prototype.constructor = LinkedViewPlugin2; LinkedViewPlugin2.prototype.requiredProps = ["idpts", "idline", "data"]; LinkedViewPlugin2.prototype.defaultProps = {} function LinkedViewPlugin2(fig, props){ mpld3.Plugin.call(this, fig, props); }; LinkedViewPlugin2.prototype.draw = function(){ var pts = mpld3.get_element(this.props.idpts); var line = mpld3.get_element(this.props.idline); var data = this.props.data; function mouseover(d, i){ line.data = data[i]; line.elements().transition() .attr("d", line.datafunc(line.data)) .style("stroke", this.style.fill); } pts.elements().on("mouseover", mouseover); }; """ def __init__(self, points, line, linedata): if isinstance(points, matplotlib.lines.Line2D): suffix = "pts" else: suffix = None self.dict_ = {"type": "linkedview", "idpts": utils.get_id(points, suffix), "idline": utils.get_id(line), "data": linedata} fig, ax = plt.subplots(3) # scatter periods and amplitudes np.random.seed(0) P = 0.2 + np.random.random(size=20) A = np.random.random(size=20) x = np.linspace(0, 10, 100) data = np.array([[x, Ai * np.sin(x / Pi)] for (Ai, Pi) in zip(A, P)]) points = ax[1].scatter(P, A, c=P + A, s=200, alpha=0.5) ax[1].set_xlabel('Period') ax[1].set_ylabel('Amplitude') # create the line object lines = ax[0].plot(x, 0 * x, '-w', lw=3, alpha=0.5) ax[0].set_ylim(-1, 1) ax[0].set_title("Hover over points to see lines") linedata = data.transpose(0, 2, 1).tolist() plugins.connect(fig, LinkedView(points, lines[0], linedata)) # second set of lines exactly the same but in a different panel lines2 = ax[2].plot(x, 0 * x, '-w', lw=3, alpha=0.5) ax[2].set_ylim(-1, 1) ax[2].set_title("Hover over points to see lines #2") plugins.connect(fig, LinkedView2(points, lines2[0], linedata)) mpld3.show()

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• sorting, average and finding the lowest number from a static array Java

  - by user3701322

  i'm trying to input students and input their results for course work and exams and what i'm having trouble with is finding the average total score, the lowest total score and printing all students in order of total scores highest - lowest import java.util.*; import java.text.*; public class Results { static String[] name = new String[100]; static int[] coursework = new int[100]; static int[] exam = new int[100]; static int count = 0; public static void main(String[] args) { Scanner input = new Scanner(System.in); boolean flag = true; while(flag) { System.out.println( "1. Add Student\n" + "2. List All Students\n" + "3. List Student Grades\n" + "4. Total Score Average\n" + "5. Highest Total Score\n" + "6. Lowest Total Score\n" + "7. List all Students and Total Scores\n" + "8. Quit\n"); System.out.print("Enter choice (1 - 8): "); int choice = input.nextInt(); switch(choice) { case 1: add(); break; case 2: listAll(); break; case 3: listGrades(); break; case 4: average(); break; case 5: highestTotal(); break; case 6: lowestTotal(); break; case 7: order(); break; case 8: flag = false; break; default: System.out.println("\nNot an option\n"); } DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss"); Date date = new Date(); System.out.println(dateFormat.format(date)); } System.out.println("\n\nHave a nice day"); }//end of main static void add() { Scanner input = new Scanner(System.in); System.out.println("Insert Name: "); String names = input.nextLine(); System.out.println("Insert Coursework: "); int courseworks = input.nextInt(); System.out.println("Insert Exam: "); int exams = input.nextInt(); name[count] = names; coursework[count] = courseworks; exam[count] = exams; count++; } static void listAll() { for(int i=0;i<count;i++) { System.out.printf("%s %d %d\n", name[i], coursework[i], exam[i]); } } static void listGrades() { for(int i=0;i<count;i++){ if(coursework[i] + exam[i] > 79) { System.out.println(name[i] + " HD"); } else if(coursework[i] + exam[i] > 69) { System.out.println(name[i] + " DI"); } else if(coursework[i] + exam[i] > 59) { System.out.println(name[i] + " CR"); } else if(coursework[i] + exam[i] > 49) { System.out.println(name[i] + " PA"); } else { System.out.println(name[i] + " NN"); } } } static void average() { } static void highestTotal() { int largest=exam[0]; String student=name[0]; for(int i=0; i<exam.length; i++){ if(exam[i]>largest){ largest = exam[i] + coursework[i]; student = name[i]; } } System.out.printf(student + ": "+ largest + "\n" ); } static void lowestTotal() { int min = 0; for(int i=0; i<=exam[i]; i++){ for(int j =0; j<=exam[i]; j++){ if(exam[i]<=exam[j] && j==exam[j]){ min = exam[i] + coursework[i]; } else{ continue; } } } System.out.printf(name + ": "+ min + "\n" ); } static void order() { } }

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• Android Out of memory regarding png image

  - by turtleboy

  I have a jpg image in my app that shows correctly. In my listview i'd like to make the image more transparent so it is easier to see the text. I changed the image to a png format and altered it's opacity in GIMP. Now that the new image is in the app drawable folder. Im getting the following error. why? 09-28 09:24:07.560: I/global(20140): call socket shutdown, tmpsocket=Socket[address=/178.250.50.40,port=80,localPort=35172] 09-28 09:24:07.570: I/global(20140): call socket shutdown, tmpsocket=Socket[address=/212.169.27.217,port=84,localPort=55656] 09-28 09:24:07.690: D/dalvikvm(20140): GC_FOR_ALLOC freed 113K, 4% free 38592K/39907K, paused 32ms 09-28 09:24:07.690: I/dalvikvm-heap(20140): Forcing collection of SoftReferences for 28072816-byte allocation 09-28 09:24:07.740: D/dalvikvm(20140): GC_BEFORE_OOM freed 9K, 4% free 38582K/39907K, paused 43ms 09-28 09:24:07.740: E/dalvikvm-heap(20140): Out of memory on a 28072816-byte allocation. 09-28 09:24:07.740: I/dalvikvm(20140): "main" prio=5 tid=1 RUNNABLE 09-28 09:24:07.740: I/dalvikvm(20140): | group="main" sCount=0 dsCount=0 obj=0x40a57490 self=0x1b6e9a8 09-28 09:24:07.740: I/dalvikvm(20140): | sysTid=20140 nice=0 sched=0/0 cgrp=default handle=1074361640 09-28 09:24:07.740: I/dalvikvm(20140): | schedstat=( 2289118000 760844000 2121 ) utm=195 stm=33 core=1 09-28 09:24:07.740: I/dalvikvm(20140): at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method) 09-28 09:24:07.740: I/dalvikvm(20140): at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:486) 09-28 09:24:07.740: I/dalvikvm(20140): at android.graphics.drawable.Drawable.createFromResourceStream(Drawable.java:773) 09-28 09:24:07.740: I/dalvikvm(20140): at android.content.res.Resources.loadDrawable(Resources.java:2042) 09-28 09:24:07.740: I/dalvikvm(20140): at android.content.res.TypedArray.getDrawable(TypedArray.java:601) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.View.<init>(View.java:2812) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.ViewGroup.<init>(ViewGroup.java:410) 09-28 09:24:07.740: I/dalvikvm(20140): at android.widget.LinearLayout.<init>(LinearLayout.java:174) 09-28 09:24:07.740: I/dalvikvm(20140): at android.widget.LinearLayout.<init>(LinearLayout.java:170) 09-28 09:24:07.740: I/dalvikvm(20140): at java.lang.reflect.Constructor.constructNative(Native Method) 09-28 09:24:07.740: I/dalvikvm(20140): at java.lang.reflect.Constructor.newInstance(Constructor.java:417) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.createView(LayoutInflater.java:586) 09-28 09:24:07.740: I/dalvikvm(20140): at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.onCreateView(LayoutInflater.java:653) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:678) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.inflate(LayoutInflater.java:466) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.inflate(LayoutInflater.java:396) 09-28 09:24:07.740: I/dalvikvm(20140): at android.view.LayoutInflater.inflate(LayoutInflater.java:352) 09-28 09:24:07.740: I/dalvikvm(20140): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:278) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.Activity.setContentView(Activity.java:1897) 09-28 09:24:07.740: I/dalvikvm(20140): at com.carefreegroup.ShowMoreDetails.onCreate(ShowMoreDetails.java:26) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.Activity.performCreate(Activity.java:4543) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1071) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2181) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2260) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.ActivityThread.access$600(ActivityThread.java:139) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1277) 09-28 09:24:07.740: I/dalvikvm(20140): at android.os.Handler.dispatchMessage(Handler.java:99) 09-28 09:24:07.740: I/dalvikvm(20140): at android.os.Looper.loop(Looper.java:156) 09-28 09:24:07.740: I/dalvikvm(20140): at android.app.ActivityThread.main(ActivityThread.java:5045) 09-28 09:24:07.740: I/dalvikvm(20140): at java.lang.reflect.Method.invokeNative(Native Method) 09-28 09:24:07.740: I/dalvikvm(20140): at java.lang.reflect.Method.invoke(Method.java:511) 09-28 09:24:07.740: I/dalvikvm(20140): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 09-28 09:24:07.740: I/dalvikvm(20140): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 09-28 09:24:07.740: I/dalvikvm(20140): at dalvik.system.NativeStart.main(Native Method) 09-28 09:24:07.740: E/dalvikvm(20140): Out of memory: Heap Size=46115KB, Allocated=38582KB, Limit=65536KB 09-28 09:24:07.740: E/dalvikvm(20140): Extra info: Footprint=39907KB, Allowed Footprint=46115KB, Trimmed=892KB 09-28 09:24:07.740: E/Bitmap_JNI(20140): Create Bitmap Failed. 09-28 09:24:07.740: A/libc(20140): Fatal signal 11 (SIGSEGV) at 0x00000004 (code=1) 09-28 09:24:09.750: I/dalvikvm(20367): Turning on JNI app bug workarounds for target SDK version 10... 09-28 09:24:09.940: D/dalvikvm(20367): GC_CONCURRENT freed 864K, 21% free 3797K/4771K, paused 2ms+2ms thanks. [update] @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.showmoredetailslayout); actualCallTime = (TextView)findViewById(R.id.actualcalltime); doubleUp = (TextView)findViewById(R.id.doubleupcallid); needName = (TextView)findViewById(R.id.needname); needNameLabel = (TextView)findViewById(R.id.neednamelabel); getRotaDetails = (Button)findViewById(R.id.buttongetrotadetails); intent = this.getIntent(); String actualTimeIn = intent.getStringExtra("actTimeIn"); String actualTimeOut = intent.getStringExtra("actTimeOut"); String doubleUpValue = intent.getStringExtra("doubleUpValue"); String needNameWithCommas = intent.getStringExtra("needNameWithCommas"); callID = intent.getStringExtra("callID"); String[] needs = needNameWithCommas.split(","); actualCallTime.setText("This call was completed at " + actualTimeIn + " -" + actualTimeOut); if( ! doubleUpValue.equalsIgnoreCase("") || doubleUpValue.equalsIgnoreCase("]")){ doubleUp.setText("This call was not a double up "); }else{ doubleUp.setText("This call was a double up " + doubleUpValue); } needNameLabel.setText("Purpose of Call: "); for (int i = 0; i < needs.length; i++){ needName.append( needs[i] + "\n"); } getRotaDetails.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(ShowMoreDetails.this, GetRotaDetails.class); intent.putExtra("callIDExtra", callID); startActivity(intent); } }); } }

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• Why does decorating a class break the descriptor protocol, thus preventing staticmethod objects from behaving as expected?

  - by Robru

  I need a little bit of help understanding the subtleties of the descriptor protocol in Python, as it relates specifically to the behavior of staticmethod objects. I'll start with a trivial example, and then iteratively expand it, examining it's behavior at each step: class Stub: @staticmethod def do_things(): """Call this like Stub.do_things(), with no arguments or instance.""" print "Doing things!" At this point, this behaves as expected, but what's going on here is a bit subtle: When you call Stub.do_things(), you are not invoking do_things directly. Instead, Stub.do_things refers to a staticmethod instance, which has wrapped the function we want up inside it's own descriptor protocol such that you are actually invoking staticmethod.__get__, which first returns the function that we want, and then gets called afterwards. >>> Stub <class __main__.Stub at 0x...> >>> Stub.do_things <function do_things at 0x...> >>> Stub.__dict__['do_things'] <staticmethod object at 0x...> >>> Stub.do_things() Doing things! So far so good. Next, I need to wrap the class in a decorator that will be used to customize class instantiation -- the decorator will determine whether to allow new instantiations or provide cached instances: def deco(cls): def factory(*args, **kwargs): # pretend there is some logic here determining # whether to make a new instance or not return cls(*args, **kwargs) return factory @deco class Stub: @staticmethod def do_things(): """Call this like Stub.do_things(), with no arguments or instance.""" print "Doing things!" Now, naturally this part as-is would be expected to break staticmethods, because the class is now hidden behind it's decorator, ie, Stub not a class at all, but an instance of factory that is able to produce instances of Stub when you call it. Indeed: >>> Stub <function factory at 0x...> >>> Stub.do_things Traceback (most recent call last): File "<stdin>", line 1, in <module> AttributeError: 'function' object has no attribute 'do_things' >>> Stub() <__main__.Stub instance at 0x...> >>> Stub().do_things <function do_things at 0x...> >>> Stub().do_things() Doing things! So far I understand what's happening here. My goal is to restore the ability for staticmethods to function as you would expect them to, even though the class is wrapped. As luck would have it, the Python stdlib includes something called functools, which provides some tools just for this purpose, ie, making functions behave more like other functions that they wrap. So I change my decorator to look like this: def deco(cls): @functools.wraps(cls) def factory(*args, **kwargs): # pretend there is some logic here determining # whether to make a new instance or not return cls(*args, **kwargs) return factory Now, things start to get interesting: >>> Stub <function Stub at 0x...> >>> Stub.do_things <staticmethod object at 0x...> >>> Stub.do_things() Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: 'staticmethod' object is not callable >>> Stub() <__main__.Stub instance at 0x...> >>> Stub().do_things <function do_things at 0x...> >>> Stub().do_things() Doing things! Wait.... what? functools copies the staticmethod over to the wrapping function, but it's not callable? Why not? What did I miss here? I was playing around with this for a bit and I actually came up with my own reimplementation of staticmethod that allows it to function in this situation, but I don't really understand why it was necessary or if this is even the best solution to this problem. Here's the complete example: class staticmethod(object): """Make @staticmethods play nice with decorated classes.""" def __init__(self, func): self.func = func def __call__(self, *args, **kwargs): """Provide the expected behavior inside decorated classes.""" return self.func(*args, **kwargs) def __get__(self, obj, objtype=None): """Re-implement the standard behavior for undecorated classes.""" return self.func def deco(cls): @functools.wraps(cls) def factory(*args, **kwargs): # pretend there is some logic here determining # whether to make a new instance or not return cls(*args, **kwargs) return factory @deco class Stub: @staticmethod def do_things(): """Call this like Stub.do_things(), with no arguments or instance.""" print "Doing things!" Indeed it works exactly as expected: >>> Stub <function Stub at 0x...> >>> Stub.do_things <__main__.staticmethod object at 0x...> >>> Stub.do_things() Doing things! >>> Stub() <__main__.Stub instance at 0x...> >>> Stub().do_things <function do_things at 0x...> >>> Stub().do_things() Doing things! What approach would you take to make a staticmethod behave as expected inside a decorated class? Is this the best way? Why doesn't the builtin staticmethod implement __call__ on it's own in order for this to just work without any fuss? Thanks.

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• Need help... how to add md5 to password field in php?

  - by jones

  Hi mates, i looking some help and nice attention here.. i bought some php script many years ago and now no suport anymore... i just want to add md5 to password field.. here my form: <?php $SQL = "SELECT * from USERS WHERE USERNAME = '$_SESSION[username]'"; $result = @mysql_query( $SQL ); $row = @mysql_fetch_array( $result ); include 'menu.php'; ?> <FORM METHOD="post" ACTION="?page=query_client"> <INPUT TYPE="hidden" NAME="controller" VALUE="USERS~update~account_details&up=1~<?php echo $row[ID]; ?>"> <TABLE CLASS="basictable"> <TR> <TD CLASS="tdmenu" WIDTH="40%">Username</TD> <TD CLASS="tdmenu" WIDTH="60%"> <b><?php echo $row[USERNAME]; ?></b> </TD> </TR> <TR> <TD CLASS="tdmenu" WIDTH="40%">Password *</TD> <TD CLASS="tdmenu" WIDTH="60%"> <INPUT TYPE="PASSWORD" NAME="PASSWORD" SIZE="40" VALUE="<?php echo $row[PASSWORD]; ?>"> </TD> </TR> <TR> <TD CLASS="tdmenu" WIDTH="40%">Email Address *</TD> <TD CLASS="tdmenu" WIDTH="60%"> <INPUT TYPE="text" NAME="EMAIL" SIZE="40" VALUE="<?php echo $row[EMAIL]; ?>"> </TD> </TR> <TR> <TD CLASS="tdmenu" WIDTH="40%">Full Name *</TD> <TD CLASS="tdmenu" WIDTH="60%"> <INPUT TYPE="text" NAME="FULLNAME" SIZE="40" VALUE="<?php echo $row[FULLNAME]; ?>"> </TD> <TR> <TD CLASS="tdmenu" WIDTH="40%">Address *</TD> <TD CLASS="tdmenu" WIDTH="60%"> <INPUT TYPE="text" NAME="ADDRESS1" SIZE="40" VALUE="<?php echo $row[ADDRESS1]; ?>"> </TD> </TR> <BR> <TABLE CLASS="basictable"> <TR> <TD CLASS="tdhead2" > <DIV ALIGN="CENTER"><B> <INPUT TYPE="submit" NAME="Submit" VALUE="Submit"> </B></DIV> </TD> </TR> </TABLE> </FORM> and the it self as query_client.php inside look like: <?PHP @session_start(); $controller = $_POST['controller']; $pieces = explode("~", $controller); $table = $pieces[0]; $qt = $pieces[1]; $return = $pieces[2]; $id = $pieces[3]; $hack = $pieces[4]; if ($qt == insert) $qt = 'INSERT INTO'; if ($qt == update) { $qt = 'UPDATE'; $end = "WHERE ID = '$id'"; } $pre = array_keys( $_POST ); mysql_query ("CREATE TABLE IF NOT EXISTS `$table` (`ID` INT NOT NULL AUTO_INCREMENT , PRIMARY KEY ( `id` ) )"); $count = count($pre); $count = $count - 2; $sql = "$qt $table SET"; for ($i=0; $i < $count; $i++) { $x=$i+1; $y = $_POST[$pre[$x]]; $d = $y; mysql_query ("ALTER TABLE `$table` ADD `$pre[$x]` TEXT NOT NULL"); $sql .= " `$pre[$x]` = '$d',"; } $sql .= " ID = '$id' $end"; $query = mysql_query($sql) or die("$sql_error" . mysql_error()); if (empty($hack)) { } else { $pieces = explode("/", $hack); $h0 = $pieces[0]; $h1 = $pieces[1]; $h2 = $pieces[2]; $h3 = $pieces[3]; $h4 = $pieces[4]; $h5 = $pieces[5]; mysql_query ("ALTER TABLE `$table` $h0 $h1 $h2 $h3 $h4 $h5"); $query = mysql_query($sql) or die("$sql_error" . mysql_error()); } if (isset($_GET[inc])) include "$_GET[inc].php"; ?> so please help me how to add md5 in PASSWORD field? thanks in advance..

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• How does Ocaml decide precedence for user-defined operators?

  - by forefinger

  I want nice operators for complex arithmetic to make my code more readable. Ocaml has a Complex module, so I just want to add operators that call those functions. The most intuitive way for me is to make a new complex operator from all of the usual operators by appending '&' to the operator symbol. Thus +& and *& will be complex addition and multiplication. I would also like ~& to be complex conjugation. If I'm going to use these operators, I want them to associate the same way that normal arithmetic associates. Based on the following sessions, they are automatically behaving the way I want, but I would like to understand why, so that I don't get horrible bugs when I introduce more operators. My current guess is that their precedence is done by lexically sorting the operator symbols according to an ordering that is consistent with normal arithmetic precedence. But I cannot confirm this. Session one: # open Complex;; # let (+&) a b = add a b;; val ( +& ) : Complex.t -> Complex.t -> Complex.t = <fun> # let ( *&) a b = mul a b;; val ( *& ) : Complex.t -> Complex.t -> Complex.t = <fun> # one +& zero *& one +& zero *& one;; - : Complex.t = {re = 1.; im = 0.} # zero +& one *& zero +& one *& zero;; - : Complex.t = {re = 0.; im = 0.} # i +& i *& i +& i *& i *& i;; - : Complex.t = {re = -1.; im = 0.} Session two: # open Complex;; # let ( *&) a b = mul a b;; val ( *& ) : Complex.t -> Complex.t -> Complex.t = <fun> # let (+&) a b = add a b;; val ( +& ) : Complex.t -> Complex.t -> Complex.t = <fun> # one +& zero *& one +& zero *& one;; - : Complex.t = {re = 1.; im = 0.} # zero +& one *& zero +& one *& zero;; - : Complex.t = {re = 0.; im = 0.} # i +& i *& i +& i *& i *& i;; - : Complex.t = {re = -1.; im = 0.} # let (~&) a = conj a;; val ( ~& ) : Complex.t -> Complex.t = <fun> # (one +& i) *& ~& (one +& i);; - : Complex.t = {re = 2.; im = 0.}

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• .NET WebRequest.PreAuthenticate not quite what it sounds like

  - by Rick Strahl

  I’ve run into the  problem a few times now: How to pre-authenticate .NET WebRequest calls doing an HTTP call to the server – essentially send authentication credentials on the very first request instead of waiting for a server challenge first? At first glance this sound like it should be easy: The .NET WebRequest object has a PreAuthenticate property which sounds like it should force authentication credentials to be sent on the first request. Looking at the MSDN example certainly looks like it does: http://msdn.microsoft.com/en-us/library/system.net.webrequest.preauthenticate.aspx Unfortunately the MSDN sample is wrong. As is the text of the Help topic which incorrectly leads you to believe that PreAuthenticate… wait for it - pre-authenticates. But it doesn’t allow you to set credentials that are sent on the first request. What this property actually does is quite different. It doesn’t send credentials on the first request but rather caches the credentials ONCE you have already authenticated once. Http Authentication is based on a challenge response mechanism typically where the client sends a request and the server responds with a 401 header requesting authentication. So the client sends a request like this: GET /wconnect/admin/wc.wc?_maintain~ShowStatus HTTP/1.1 Host: rasnote User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 4.0.20506) Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en,de;q=0.7,en-us;q=0.3 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive and the server responds with: HTTP/1.1 401 Unauthorized Cache-Control: private Content-Type: text/html; charset=utf-8 Server: Microsoft-IIS/7.5 WWW-Authenticate: basic realm=rasnote" X-AspNet-Version: 2.0.50727 WWW-Authenticate: Negotiate WWW-Authenticate: NTLM WWW-Authenticate: Basic realm="rasnote" X-Powered-By: ASP.NET Date: Tue, 27 Oct 2009 00:58:20 GMT Content-Length: 5163 plus the actual error message body. The client then is responsible for re-sending the current request with the authentication token information provided (in this case Basic Auth): GET /wconnect/admin/wc.wc?_maintain~ShowStatus HTTP/1.1 Host: rasnote User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 4.0.20506) Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en,de;q=0.7,en-us;q=0.3 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive Cookie: TimeTrakker=2HJ1998WH06696; WebLogCommentUser=Rick Strahl|http://www.west-wind.com/|[email protected]; WebStoreUser=b8bd0ed9 Authorization: Basic cgsf12aDpkc2ZhZG1zMA== Once the authorization info is sent the server responds with the actual page result. Now if you use WebRequest (or WebClient) the default behavior is to re-authenticate on every request that requires authorization. This means if you look in  Fiddler or some other HTTP client Proxy that captures requests you’ll see that each request re-authenticates: Here are two requests fired back to back: and you can see the 401 challenge, the 200 response for both requests. If you watch this same conversation between a browser and a server you’ll notice that the first 401 is also there but the subsequent 401 requests are not present. WebRequest.PreAuthenticate And this is precisely what the WebRequest.PreAuthenticate property does: It’s a caching mechanism that caches the connection credentials for a given domain in the active process and resends it on subsequent requests. It does not send credentials on the first request but it will cache credentials on subsequent requests after authentication has succeeded: string url = "http://rasnote/wconnect/admin/wc.wc?_maintain~ShowStatus"; HttpWebRequest req = HttpWebRequest.Create(url) as HttpWebRequest; req.PreAuthenticate = true; req.Credentials = new NetworkCredential("rick", "secret", "rasnote"); req.AuthenticationLevel = System.Net.Security.AuthenticationLevel.MutualAuthRequested; req.UserAgent = ": Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 4.0.20506)"; WebResponse resp = req.GetResponse(); resp.Close(); req = HttpWebRequest.Create(url) as HttpWebRequest; req.PreAuthenticate = true; req.Credentials = new NetworkCredential("rstrahl", "secret", "rasnote"); req.AuthenticationLevel = System.Net.Security.AuthenticationLevel.MutualAuthRequested; req.UserAgent = ": Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 4.0.20506)"; resp = req.GetResponse(); which results in the desired sequence: where only the first request doesn’t send credentials. This is quite useful as it saves quite a few round trips to the server – bascially it saves one auth request request for every authenticated request you make. In most scenarios I think you’d want to send these credentials this way but one downside to this is that there’s no way to log out the client. Since the client always sends the credentials once authenticated only an explicit operation ON THE SERVER can undo the credentials by forcing another login explicitly (ie. re-challenging with a forced 401 request). Forcing Basic Authentication Credentials on the first Request On a few occasions I’ve needed to send credentials on a first request – mainly to some oddball third party Web Services (why you’d want to use Basic Auth on a Web Service is beyond me – don’t ask but it’s not uncommon in my experience). This is true of certain services that are using Basic Authentication (especially some Apache based Web Services) and REQUIRE that the authentication is sent right from the first request. No challenge first. Ugly but there it is. Now the following works only with Basic Authentication because it’s pretty straight forward to create the Basic Authorization ‘token’ in code since it’s just an unencrypted encoding of the user name and password into base64. As you might guess this is totally unsecure and should only be used when using HTTPS/SSL connections (i’m not in this example so I can capture the Fiddler trace and my local machine doesn’t have a cert installed, but for production apps ALWAYS use SSL with basic auth). The idea is that you simply add the required Authorization header to the request on your own along with the authorization string that encodes the username and password: string url = "http://rasnote/wconnect/admin/wc.wc?_maintain~ShowStatus"; HttpWebRequest req = HttpWebRequest.Create(url) as HttpWebRequest; string user = "rick"; string pwd = "secret"; string domain = "www.west-wind.com"; string auth = "Basic " + Convert.ToBase64String(System.Text.Encoding.Default.GetBytes(user + ":" + pwd)); req.PreAuthenticate = true; req.AuthenticationLevel = System.Net.Security.AuthenticationLevel.MutualAuthRequested;req.Headers.Add("Authorization", auth); req.UserAgent = ": Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 4.0.20506)"; WebResponse resp = req.GetResponse(); resp.Close(); This works and causes the request to immediately send auth information to the server. However, this only works with Basic Auth because you can actually create the authentication credentials easily on the client because it’s essentially clear text. The same doesn’t work for Windows or Digest authentication since you can’t easily create the authentication token on the client and send it to the server. Another issue with this approach is that PreAuthenticate has no effect when you manually force the authentication. As far as Web Request is concerned it never sent the authentication information so it’s not actually caching the value any longer. If you run 3 requests in a row like this: string url = "http://rasnote/wconnect/admin/wc.wc?_maintain~ShowStatus"; HttpWebRequest req = HttpWebRequest.Create(url) as HttpWebRequest; string user = "ricks"; string pwd = "secret"; string domain = "www.west-wind.com"; string auth = "Basic " + Convert.ToBase64String(System.Text.Encoding.Default.GetBytes(user + ":" + pwd)); req.PreAuthenticate = true; req.Headers.Add("Authorization", auth); req.UserAgent = ": Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 4.0.20506)"; WebResponse resp = req.GetResponse(); resp.Close(); req = HttpWebRequest.Create(url) as HttpWebRequest; req.PreAuthenticate = true; req.Credentials = new NetworkCredential(user, pwd, domain); req.UserAgent = ": Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 4.0.20506)"; resp = req.GetResponse(); resp.Close(); req = HttpWebRequest.Create(url) as HttpWebRequest; req.PreAuthenticate = true; req.Credentials = new NetworkCredential(user, pwd, domain); req.UserAgent = ": Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 4.0.20506)"; resp = req.GetResponse(); you’ll find the trace looking like this: where the first request (the one we explicitly add the header to) authenticates, the second challenges, and any subsequent ones then use the PreAuthenticate credential caching. In effect you’ll end up with one extra 401 request in this scenario, which is still better than 401 challenges on each request. Getting Access to WebRequest in Classic .NET Web Service Clients If you’re running a classic .NET Web Service client (non-WCF) one issue with the above is how do you get access to the WebRequest to actually add the custom headers to do the custom Authentication described above? One easy way is to implement a partial class that allows you add headers with something like this: public partial class TaxService { protected NameValueCollection Headers = new NameValueCollection(); public void AddHttpHeader(string key, string value) { this.Headers.Add(key,value); } public void ClearHttpHeaders() { this.Headers.Clear(); } protected override WebRequest GetWebRequest(Uri uri) { HttpWebRequest request = (HttpWebRequest) base.GetWebRequest(uri); request.Headers.Add(this.Headers); return request; } } where TaxService is the name of the .NET generated proxy class. In code you can then call AddHttpHeader() anywhere to add additional headers which are sent as part of the GetWebRequest override. Nice and simple once you know where to hook it. For WCF there’s a bit more work involved by creating a message extension as described here: http://weblogs.asp.net/avnerk/archive/2006/04/26/Adding-custom-headers-to-every-WCF-call-_2D00_-a-solution.aspx. FWIW, I think that HTTP header manipulation should be readily available on any HTTP based Web Service client DIRECTLY without having to subclass or implement a special interface hook. But alas a little extra work is required in .NET to make this happen Not a Common Problem, but when it happens… This has been one of those issues that is really rare, but it’s bitten me on several occasions when dealing with oddball Web services – a couple of times in my own work interacting with various Web Services and a few times on customer projects that required interaction with credentials-first services. Since the servers determine the protocol, we don’t have a choice but to follow the protocol. Lovely following standards that implementers decide to ignore, isn’t it? :-}© Rick Strahl, West Wind Technologies, 2005-2010Posted in .NET  CSharp  Web Services  

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• Microsoft and jQuery

  - by Rick Strahl

  The jQuery JavaScript library has been steadily getting more popular and with recent developments from Microsoft, jQuery is also getting ever more exposure on the ASP.NET platform including now directly from Microsoft. jQuery is a light weight, open source DOM manipulation library for JavaScript that has changed how many developers think about JavaScript. You can download it and find more information on jQuery on www.jquery.com. For me jQuery has had a huge impact on how I develop Web applications and was probably the main reason I went from dreading to do JavaScript development to actually looking forward to implementing client side JavaScript functionality. It has also had a profound impact on my JavaScript skill level for me by seeing how the library accomplishes things (and often reviewing the terse but excellent source code). jQuery made an uncomfortable development platform (JavaScript + DOM) a joy to work on. Although jQuery is by no means the only JavaScript library out there, its ease of use, small size, huge community of plug-ins and pure usefulness has made it easily the most popular JavaScript library available today. As a long time jQuery user, I’ve been excited to see the developments from Microsoft that are bringing jQuery to more ASP.NET developers and providing more integration with jQuery for ASP.NET’s core features rather than relying on the ASP.NET AJAX library. Microsoft and jQuery – making Friends jQuery is an open source project but in the last couple of years Microsoft has really thrown its weight behind supporting this open source library as a supported component on the Microsoft platform. When I say supported I literally mean supported: Microsoft now offers actual tech support for jQuery as part of their Product Support Services (PSS) as jQuery integration has become part of several of the ASP.NET toolkits and ships in several of the default Web project templates in Visual Studio 2010. The ASP.NET MVC 3 framework (still in Beta) also uses jQuery for a variety of client side support features including client side validation and we can look forward toward more integration of client side functionality via jQuery in both MVC and WebForms in the future. In other words jQuery is becoming an optional but included component of the ASP.NET platform. PSS support means that support staff will answer jQuery related support questions as part of any support incidents related to ASP.NET which provides some piece of mind to some corporate development shops that require end to end support from Microsoft. In addition to including jQuery and supporting it, Microsoft has also been getting involved in providing development resources for extending jQuery’s functionality via plug-ins. Microsoft’s last version of the Microsoft Ajax Library – which is the successor to the native ASP.NET AJAX Library – included some really cool functionality for client templates, databinding and localization. As it turns out Microsoft has rebuilt most of that functionality using jQuery as the base API and provided jQuery plug-ins of these components. Very recently these three plug-ins were submitted and have been approved for inclusion in the official jQuery plug-in repository and been taken over by the jQuery team for further improvements and maintenance. Even more surprising: The jQuery-templates component has actually been approved for inclusion in the next major update of the jQuery core in jQuery V1.5, which means it will become a native feature that doesn’t require additional script files to be loaded. Imagine this – an open source contribution from Microsoft that has been accepted into a major open source project for a core feature improvement. Microsoft has come a long way indeed! What the Microsoft Involvement with jQuery means to you For Microsoft jQuery support is a strategic decision that affects their direction in client side development, but nothing stopped you from using jQuery in your applications prior to Microsoft’s official backing and in fact a large chunk of developers did so readily prior to Microsoft’s announcement. Official support from Microsoft brings a few benefits to developers however. jQuery support in Visual Studio 2010 means built-in support for jQuery IntelliSense, automatically added jQuery scripts in many projects types and a common base for client side functionality that actually uses what most developers are already using. If you have already been using jQuery and were worried about straying from the Microsoft line and their internal Microsoft Ajax Library – worry no more. With official support and the change in direction towards jQuery Microsoft is now following along what most in the ASP.NET community had already been doing by using jQuery, which is likely the reason for Microsoft’s shift in direction in the first place. ASP.NET AJAX and the Microsoft AJAX Library weren’t bad technology – there was tons of useful functionality buried in these libraries. However, these libraries never got off the ground, mainly because early incarnations were squarely aimed at control/component developers rather than application developers. For all the functionality that these controls provided for control developers they lacked in useful and easily usable application developer functionality that was easily accessible in day to day client side development. The result was that even though Microsoft shipped support for these tools in the box (in .NET 3.5 and 4.0), other than for the internal support in ASP.NET for things like the UpdatePanel and the ASP.NET AJAX Control Toolkit as well as some third party vendors, the Microsoft client libraries were largely ignored by the developer community opening the door for other client side solutions. Microsoft seems to be acknowledging developer choice in this case: Many more developers were going down the jQuery path rather than using the Microsoft built libraries and there seems to be little sense in continuing development of a technology that largely goes unused by the majority of developers. Kudos for Microsoft for recognizing this and gracefully changing directions. Note that even though there will be no further development in the Microsoft client libraries they will continue to be supported so if you’re using them in your applications there’s no reason to start running for the exit in a panic and start re-writing everything with jQuery. Although that might be a reasonable choice in some cases, jQuery and the Microsoft libraries work well side by side so that you can leave existing solutions untouched even as you enhance them with jQuery. The Microsoft jQuery Plug-ins – Solid Core Features One of the most interesting developments in Microsoft’s embracing of jQuery is that Microsoft has started contributing to jQuery via standard mechanism set for jQuery developers: By submitting plug-ins. Microsoft took some of the nicest new features of the unpublished Microsoft Ajax Client Library and re-wrote these components for jQuery and then submitted them as plug-ins to the jQuery plug-in repository. Accepted plug-ins get taken over by the jQuery team and that’s exactly what happened with the three plug-ins submitted by Microsoft with the templating plug-in even getting slated to be published as part of the jQuery core in the next major release (1.5). The following plug-ins are provided by Microsoft: jQuery Templates – a client side template rendering engine jQuery Data Link – a client side databinder that can synchronize changes without code jQuery Globalization – provides formatting and conversion features for dates and numbers The first two are ports of functionality that was slated for the Microsoft Ajax Library while functionality for the globalization library provides functionality that was already found in the original ASP.NET AJAX library. To me all three plug-ins address a pressing need in client side applications and provide functionality I’ve previously used in other incarnations, but with more complete implementations. Let’s take a close look at these plug-ins. jQuery Templates http://api.jquery.com/category/plugins/templates/ Client side templating is a key component for building rich JavaScript applications in the browser. Templating on the client lets you avoid from manually creating markup by creating DOM nodes and injecting them individually into the document via code. Rather you can create markup templates – similar to the way you create classic ASP server markup – and merge data into these templates to render HTML which you can then inject into the document or replace existing content with. Output from templates are rendered as a jQuery matched set and can then be easily inserted into the document as needed. Templating is key to minimize client side code and reduce repeated code for rendering logic. Instead a single template can be used in many places for updating and adding content to existing pages. Further if you build pure AJAX interfaces that rely entirely on client rendering of the initial page content, templates allow you to a use a single markup template to handle all rendering of each specific HTML section/element. I’ve used a number of different client rendering template engines with jQuery in the past including jTemplates (a PHP style templating engine) and a modified version of John Resig’s MicroTemplating engine which I built into my own set of libraries because it’s such a commonly used feature in my client side applications. jQuery templates adds a much richer templating model that allows for sub-templates and access to the data items. Like John Resig’s original Micro Template engine, the core basics of the templating engine create JavaScript code which means that templates can include JavaScript code. To give you a basic idea of how templates work imagine I have an application that downloads a set of stock quotes based on a symbol list then displays them in the document. To do this you can create an ‘item’ template that describes how each of the quotes is renderd as a template inside of the document: <script id="stockTemplate" type="text/x-jquery-tmpl"> <div id="divStockQuote" class="errordisplay" style="width: 500px;"> <div class="label">Company:</div><div><b>${Company}(${Symbol})</b></div> <div class="label">Last Price:</div><div>${LastPrice}</div> <div class="label">Net Change:</div><div> {{if NetChange > 0}} <b style="color:green" >${NetChange}</b> {{else}} <b style="color:red" >${NetChange}</b> {{/if}} </div> <div class="label">Last Update:</div><div>${LastQuoteTimeString}</div> </div> </script> The ‘template’ is little more than HTML with some markup expressions inside of it that define the template language. Notice the embedded ${} expressions which reference data from the quote objects returned from an AJAX call on the server. You can embed any JavaScript or value expression in these template expressions. There are also a number of structural commands like {{if}} and {{each}} that provide for rudimentary logic inside of your templates as well as commands ({{tmpl}} and {{wrap}}) for nesting templates. You can find more about the full set of markup expressions available in the documentation. To load up this data you can use code like the following: <script type="text/javascript"> //var Proxy = new ServiceProxy("../PageMethods/PageMethodsService.asmx/"); $(document).ready(function () { $("#btnGetQuotes").click(GetQuotes); }); function GetQuotes() { var symbols = $("#txtSymbols").val().split(","); $.ajax({ url: "../PageMethods/PageMethodsService.asmx/GetStockQuotes", data: JSON.stringify({ symbols: symbols }), // parameter map type: "POST", // data has to be POSTed contentType: "application/json", timeout: 10000, dataType: "json", success: function (result) { var quotes = result.d; var jEl = $("#stockTemplate").tmpl(quotes); $("#quoteDisplay").empty().append(jEl); }, error: function (xhr, status) { alert(status + "\r\n" + xhr.responseText); } }); }; </script> In this case an ASMX AJAX service is called to retrieve the stock quotes. The service returns an array of quote objects. The result is returned as an object with the .d property (in Microsoft service style) that returns the actual array of quotes. The template is applied with: var jEl = $("#stockTemplate").tmpl(quotes); which selects the template script tag and uses the .tmpl() function to apply the data to it. The result is a jQuery matched set of elements that can then be appended to the quote display element in the page. The template is merged against an array in this example. When the result is an array the template is automatically applied to each each array item. If you pass a single data item – like say a stock quote – the template works exactly the same way but is applied only once. Templates also have access to a $data item which provides the current data item and information about the tempalte that is currently executing. This makes it possible to keep context within the context of the template itself and also to pass context from a parent template to a child template which is very powerful. Templates can be evaluated by using the template selector and calling the .tmpl() function on the jQuery matched set as shown above or you can use the static $.tmpl() function to provide a template as a string. This allows you to dynamically create templates in code or – more likely – to load templates from the server via AJAX calls. In short there are options The above shows off some of the basics, but there’s much for functionality available in the template engine. Check the documentation link for more information and links to additional examples. The plug-in download also comes with a number of examples that demonstrate functionality. jQuery templates will become a native component in jQuery Core 1.5, so it’s definitely worthwhile checking out the engine today and get familiar with this interface. As much as I’m stoked about templating becoming part of the jQuery core because it’s such an integral part of many applications, there are also a couple shortcomings in the current incarnation: Lack of Error Handling Currently if you embed an expression that is invalid it’s simply not rendered. There’s no error rendered into the template nor do the various  template functions throw errors which leaves finding of bugs as a runtime exercise. I would like some mechanism – optional if possible – to be able to get error info of what is failing in a template when it’s rendered. No String Output Templates are always rendered into a jQuery matched set and there’s no way that I can see to directly render to a string. String output can be useful for debugging as well as opening up templating for creating non-HTML string output. Limited JavaScript Access Unlike John Resig’s original MicroTemplating Engine which was entirely based on JavaScript code generation these templates are limited to a few structured commands that can ‘execute’. There’s no code execution inside of script code which means you’re limited to calling expressions available in global objects or the data item passed in. This may or may not be a big deal depending on the complexity of your template logic. Error handling has been discussed quite a bit and it’s likely there will be some solution to that particualar issue by the time jQuery templates ship. The others are relatively minor issues but something to think about anyway. jQuery Data Link http://api.jquery.com/category/plugins/data-link/ jQuery Data Link provides the ability to do two-way data binding between input controls and an underlying object’s properties. The typical scenario is linking a textbox to a property of an object and have the object updated when the text in the textbox is changed and have the textbox change when the value in the object or the entire object changes. The plug-in also supports converter functions that can be applied to provide the conversion logic from string to some other value typically necessary for mapping things like textbox string input to say a number property and potentially applying additional formatting and calculations. In theory this sounds great, however in reality this plug-in has some serious usability issues. Using the plug-in you can do things like the following to bind data: person = { firstName: "rick", lastName: "strahl"}; $(document).ready( function() { // provide for two-way linking of inputs $("form").link(person); // bind to non-input elements explicitly $("#objFirst").link(person, { firstName: { name: "objFirst", convertBack: function (value, source, target) { $(target).text(value); } } }); $("#objLast").link(person, { lastName: { name: "objLast", convertBack: function (value, source, target) { $(target).text(value); } } }); }); This code hooks up two-way linking between a couple of textboxes on the page and the person object. The first line in the .ready() handler provides mapping of object to form field with the same field names as properties on the object. Note that .link() does NOT bind items into the textboxes when you call .link() – changes are mapped only when values change and you move out of the field. Strike one. The two following commands allow manual binding of values to specific DOM elements which is effectively a one-way bind. You specify the object and a then an explicit mapping where name is an ID in the document. The converter is required to explicitly assign the value to the element. Strike two. You can also detect changes to the underlying object and cause updates to the input elements bound. Unfortunately the syntax to do this is not very natural as you have to rely on the jQuery data object. To update an object’s properties and get change notification looks like this: function updateFirstName() { $(person).data("firstName", person.firstName + " (code updated)"); } This works fine in causing any linked fields to be updated. In the bindings above both the firstName input field and objFirst DOM element gets updated. But the syntax requires you to use a jQuery .data() call for each property change to ensure that the changes are tracked properly. Really? Sure you’re binding through multiple layers of abstraction now but how is that better than just manually assigning values? The code savings (if any) are going to be minimal. As much as I would like to have a WPF/Silverlight/Observable-like binding mechanism in client script, this plug-in doesn’t help much towards that goal in its current incarnation. While you can bind values, the ‘binder’ is too limited to be really useful. If initial values can’t be assigned from the mappings you’re going to end up duplicating work loading the data using some other mechanism. There’s no easy way to re-bind data with a different object altogether since updates trigger only through the .data members. Finally, any non-input elements have to be bound via code that’s fairly verbose and frankly may be more voluminous than what you might write by hand for manual binding and unbinding. Two way binding can be very useful but it has to be easy and most importantly natural. If it’s more work to hook up a binding than writing a couple of lines to do binding/unbinding this sort of thing helps very little in most scenarios. In talking to some of the developers the feature set for Data Link is not complete and they are still soliciting input for features and functionality. If you have ideas on how you want this feature to be more useful get involved and post your recommendations. As it stands, it looks to me like this component needs a lot of love to become useful. For this component to really provide value, bindings need to be able to be refreshed easily and work at the object level, not just the property level. It seems to me we would be much better served by a model binder object that can perform these binding/unbinding tasks in bulk rather than a tool where each link has to be mapped first. I also find the choice of creating a jQuery plug-in questionable – it seems a standalone object – albeit one that relies on the jQuery library – would provide a more intuitive interface than the current forcing of options onto a plug-in style interface. Out of the three Microsoft created components this is by far the least useful and least polished implementation at this point. jQuery Globalization http://github.com/jquery/jquery-global Globalization in JavaScript applications often gets short shrift and part of the reason for this is that natively in JavaScript there’s little support for formatting and parsing of numbers and dates. There are a number of JavaScript libraries out there that provide some support for globalization, but most are limited to a particular portion of globalization. As .NET developers we’re fairly spoiled by the richness of APIs provided in the framework and when dealing with client development one really notices the lack of these features. While you may not necessarily need to localize your application the globalization plug-in also helps with some basic tasks for non-localized applications: Dealing with formatting and parsing of dates and time values. Dates in particular are problematic in JavaScript as there are no formatters whatsoever except the .toString() method which outputs a verbose and next to useless long string. With the globalization plug-in you get a good chunk of the formatting and parsing functionality that the .NET framework provides on the server. You can write code like the following for example to format numbers and dates: var date = new Date(); var output = $.format(date, "MMM. dd, yy") + "\r\n" + $.format(date, "d") + "\r\n" + // 10/25/2010 $.format(1222.32213, "N2") + "\r\n" + $.format(1222.33, "c") + "\r\n"; alert(output); This becomes even more useful if you combine it with templates which can also include any JavaScript expressions. Assuming the globalization plug-in is loaded you can create template expressions that use the $.format function. Here’s the template I used earlier for the stock quote again with a couple of formats applied: <script id="stockTemplate" type="text/x-jquery-tmpl"> <div id="divStockQuote" class="errordisplay" style="width: 500px;"> <div class="label">Company:</div><div><b>${Company}(${Symbol})</b></div> <div class="label">Last Price:</div> <div>${$.format(LastPrice,"N2")}</div> <div class="label">Net Change:</div><div> {{if NetChange > 0}} <b style="color:green" >${NetChange}</b> {{else}} <b style="color:red" >${NetChange}</b> {{/if}} </div> <div class="label">Last Update:</div> <div>${$.format(LastQuoteTime,"MMM dd, yyyy")}</div> </div> </script> There are also parsing methods that can parse dates and numbers from strings into numbers easily: alert($.parseDate("25.10.2010")); alert($.parseInt("12.222")); // de-DE uses . for thousands separators As you can see culture specific options are taken into account when parsing. The globalization plugin provides rich support for a variety of locales: Get a list of all available cultures Query cultures for culture items (like currency symbol, separators etc.) Localized string names for all calendar related items (days of week, months) Generated off of .NET’s supported locales In short you get much of the same functionality that you already might be using in .NET on the server side. The plugin includes a huge number of locales and an Globalization.all.min.js file that contains the text defaults for each of these locales as well as small locale specific script files that define each of the locale specific settings. It’s highly recommended that you NOT use the huge globalization file that includes all locales, but rather add script references to only those languages you explicitly care about. Overall this plug-in is a welcome helper. Even if you use it with a single locale (like en-US) and do no other localization, you’ll gain solid support for number and date formatting which is a vital feature of many applications. Changes for Microsoft It’s good to see Microsoft coming out of its shell and away from the ‘not-built-here’ mentality that has been so pervasive in the past. It’s especially good to see it applied to jQuery – a technology that has stood in drastic contrast to Microsoft’s own internal efforts in terms of design, usage model and… popularity. It’s great to see that Microsoft is paying attention to what customers prefer to use and supporting the customer sentiment – even if it meant drastically changing course of policy and moving into a more open and sharing environment in the process. The additional jQuery support that has been introduced in the last two years certainly has made lives easier for many developers on the ASP.NET platform. It’s also nice to see Microsoft submitting proposals through the standard jQuery process of plug-ins and getting accepted for various very useful projects. Certainly the jQuery Templates plug-in is going to be very useful to many especially since it will be baked into the jQuery core in jQuery 1.5. I hope we see more of this type of involvement from Microsoft in the future. Kudos!© Rick Strahl, West Wind Technologies, 2005-2010Posted in jQuery  ASP.NET  

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• Loading jQuery Consistently in a .NET Web App

  - by Rick Strahl

  One thing that frequently comes up in discussions when using jQuery is how to best load the jQuery library (as well as other commonly used and updated libraries) in a Web application. Specifically the issue is the one of versioning and making sure that you can easily update and switch versions of script files with application wide settings in one place and having your script usage reflect those settings in the entire application on all pages that use the script. Although I use jQuery as an example here, the same concepts can be applied to any script library - for example in my Web libraries I use the same approach for jQuery.ui and my own internal jQuery support library. The concepts used here can be applied both in WebForms and MVC. Loading jQuery Properly From CDN Before we look at a generic way to load jQuery via some server logic, let me first point out my preferred way to embed jQuery into the page. I use the Google CDN to load jQuery and then use a fallback URL to handle the offline or no Internet connection scenario. Why use a CDN? CDN links tend to be loaded more quickly since they are very likely to be cached in user's browsers already as jQuery CDN is used by many, many sites on the Web. Using a CDN also removes load from your Web server and puts the load bearing on the CDN provider - in this case Google - rather than on your Web site. On the downside, CDN links gives the provider (Google, Microsoft) yet another way to track users through their Web usage. Here's how I use jQuery CDN plus a fallback link on my WebLog for example: <!DOCTYPE HTML> <html> <head> <script src="//ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script> <script> if (typeof (jQuery) == 'undefined') document.write(unescape("%3Cscript " + "src='/Weblog/wwSC.axd?r=Westwind.Web.Controls.Resources.jquery.js' %3E%3C/script%3E")); </script> <title>Rick Strahl's Web Log</title> ... </head>   You can see that the CDN is referenced first, followed by a small script block that checks to see whether jQuery was loaded (jQuery object exists). If it didn't load another script reference is added to the document dynamically pointing to a backup URL. In this case my backup URL points at a WebResource in my Westwind.Web  assembly, but the URL can also be local script like src="/scripts/jquery.min.js". Important: Use the proper Protocol/Scheme for  for CDN Urls [updated based on comments] If you're using a CDN to load an external script resource you should always make sure that the script is loaded with the same protocol as the parent page to avoid mixed content warnings by the browser. You don't want to load a script link to an http:// resource when you're on an https:// page. The easiest way to use this is by using a protocol relative URL: <script src="//ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script> which is an easy way to load resources from other domains. This URL syntax will automatically use the parent page's protocol (or more correctly scheme). As long as the remote domains support both http:// and https:// access this should work. BTW this also works in CSS (with some limitations) and links. BTW, I didn't know about this until it was pointed out in the comments. This is a very useful feature for many things - ah the benefits of my blog to myself :-) Version Numbers When you use a CDN you notice that you have to reference a specific version of jQuery. When using local files you may not have to do this as you can rename your private copy of jQuery.js, but for CDN the references are always versioned. The version number is of course very important to ensure you getting the version you have tested with, but it's also important to the provider because it ensures that cached content is always correct. If an existing file was updated the updates might take a very long time to get past the locally cached content and won't refresh properly. The version number ensures you get the right version and not some cached content that has been changed but not updated in your cache. On the other hand version numbers also mean that once you decide to use a new version of the script you now have to change all your script references in your pages. Depending on whether you use some sort of master/layout page or not this may or may not be easy in your application. Even if you do use master/layout pages, chances are that you probably have a few of them and at the very least all of those have to be updated for the scripts. If you use individual pages for all content this issue then spreads to all of your pages. Search and Replace in Files will do the trick, but it's still something that's easy to forget and worry about. Personaly I think it makes sense to have a single place where you can specify common script libraries that you want to load and more importantly which versions thereof and where they are loaded from. Loading Scripts via Server Code Script loading has always been important to me and as long as I can remember I've always built some custom script loading routines into my Web frameworks. WebForms makes this fairly easy because it has a reasonably useful script manager (ClientScriptManager and the ScriptManager) which allow injecting script into the page easily from anywhere in the Page cycle. What's nice about these components is that they allow scripts to be injected by controls so components can wrap up complex script/resource dependencies more easily without having to require long lists of CSS/Scripts/Image includes. In MVC or pure script driven applications like Razor WebPages  the process is more raw, requiring you to embed script references in the right place. But its also more immediate - it lets you know exactly which versions of scripts to use because you have to manually embed them. In WebForms with different controls loading resources this often can get confusing because it's quite possible to load multiple versions of the same script library into a page, the results of which are less than optimal… In this post I look a simple routine that embeds jQuery into the page based on a few application wide configuration settings. It returns only a string of the script tags that can be manually embedded into a Page template. It's a small function that merely a string of the script tags shown at the begging of this post along with some options on how that string is comprised. You'll be able to specify in one place which version loads and then all places where the help function is used will automatically reflect this selection. Options allow specification of the jQuery CDN Url, the fallback Url and where jQuery should be loaded from (script folder, Resource or CDN in my case). While this is specific to jQuery you can apply this to other resources as well. For example I use a similar approach with jQuery.ui as well using practically the same semantics. Providing Resources in ControlResources In my Westwind.Web Web utility library I have a class called ControlResources which is responsible for holding resource Urls, resource IDs and string contants that reference those resource IDs. The library also provides a few helper methods for loading common scriptscripts into a Web page. There are specific versions for WebForms which use the ClientScriptManager/ScriptManager and script link methods that can be used in any .NET technology that can embed an expression into the output template (or code for that matter). The ControlResources class contains mostly static content - references to resources mostly. But it also contains a few static properties that configure script loading: A Script LoadMode (CDN, Resource, or script url) A default CDN Url A fallback url They are  static properties in the ControlResources class: public class ControlResources { /// <summary> /// Determines what location jQuery is loaded from /// </summary> public static JQueryLoadModes jQueryLoadMode = JQueryLoadModes.ContentDeliveryNetwork; /// <summary> /// jQuery CDN Url on Google /// </summary> public static string jQueryCdnUrl = "//ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"; /// <summary> /// jQuery CDN Url on Google /// </summary> public static string jQueryUiCdnUrl = "//ajax.googleapis.com/ajax/libs/jqueryui/1.8.16/jquery-ui.min.js"; /// <summary> /// jQuery UI fallback Url if CDN is unavailable or WebResource is used /// Note: The file needs to exist and hold the minimized version of jQuery ui /// </summary> public static string jQueryUiLocalFallbackUrl = "~/scripts/jquery-ui.min.js"; } These static properties are fixed values that can be changed at application startup to reflect your preferences. Since they're static they are application wide settings and respected across the entire Web application running. It's best to set these default in Application_Init or similar startup code if you need to change them for your application: protected void Application_Start(object sender, EventArgs e) { // Force jQuery to be loaded off Google Content Network ControlResources.jQueryLoadMode = JQueryLoadModes.ContentDeliveryNetwork; // Allow overriding of the Cdn url ControlResources.jQueryCdnUrl = "http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js"; // Route to our own internal handler App.OnApplicationStart(); } With these basic settings in place you can then embed expressions into a page easily. In WebForms use: <!DOCTYPE html> <html> <head runat="server"> <%= ControlResources.jQueryLink() %> <script src="scripts/ww.jquery.min.js"></script> </head> In Razor use: <!DOCTYPE html> <html> <head> @Html.Raw(ControlResources.jQueryLink()) <script src="scripts/ww.jquery.min.js"></script> </head> Note that in Razor you need to use @Html.Raw() to force the string NOT to escape. Razor by default escapes string results and this ensures that the HTML content is properly expanded as raw HTML text. Both the WebForms and Razor output produce: <!DOCTYPE html> <html> <head> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js" type="text/javascript"></script> <script type="text/javascript"> if (typeof (jQuery) == 'undefined') document.write(unescape("%3Cscript src='/WestWindWebToolkitWeb/WebResource.axd?d=-b6oWzgbpGb8uTaHDrCMv59VSmGhilZP5_T_B8anpGx7X-PmW_1eu1KoHDvox-XHqA1EEb-Tl2YAP3bBeebGN65tv-7-yAimtG4ZnoWH633pExpJor8Qp1aKbk-KQWSoNfRC7rQJHXVP4tC0reYzVw2&t=634535391996872492' type='text/javascript'%3E%3C/script%3E"));</script> <script src="scripts/ww.jquery.min.js"></script> </head> which produces the desired effect for both CDN load and fallback URL. The implementation of jQueryLink is pretty basic of course: /// <summary> /// Inserts a script link to load jQuery into the page based on the jQueryLoadModes settings /// of this class. Default load is by CDN plus WebResource fallback /// </summary> /// <param name="url"> /// An optional explicit URL to load jQuery from. Url is resolved. /// When specified no fallback is applied /// </param> /// <returns>full script tag and fallback script for jQuery to load</returns> public static string jQueryLink(JQueryLoadModes jQueryLoadMode = JQueryLoadModes.Default, string url = null) { string jQueryUrl = string.Empty; string fallbackScript = string.Empty; if (jQueryLoadMode == JQueryLoadModes.Default) jQueryLoadMode = ControlResources.jQueryLoadMode; if (!string.IsNullOrEmpty(url)) jQueryUrl = WebUtils.ResolveUrl(url); else if (jQueryLoadMode == JQueryLoadModes.WebResource) { Page page = new Page(); jQueryUrl = page.ClientScript.GetWebResourceUrl(typeof(ControlResources), ControlResources.JQUERY_SCRIPT_RESOURCE); } else if (jQueryLoadMode == JQueryLoadModes.ContentDeliveryNetwork) { jQueryUrl = ControlResources.jQueryCdnUrl; if (!string.IsNullOrEmpty(jQueryCdnUrl)) { // check if jquery loaded - if it didn't we're not online and use WebResource fallbackScript = @"<script type=""text/javascript"">if (typeof(jQuery) == 'undefined') document.write(unescape(""%3Cscript src='{0}' type='text/javascript'%3E%3C/script%3E""));</script>"; fallbackScript = string.Format(fallbackScript, WebUtils.ResolveUrl(ControlResources.jQueryCdnFallbackUrl)); } } string output = "<script src=\"" + jQueryUrl + "\" type=\"text/javascript\"></script>"; // add in the CDN fallback script code if (!string.IsNullOrEmpty(fallbackScript)) output += "\r\n" + fallbackScript + "\r\n"; return output; } There's one dependency here on WebUtils.ResolveUrl() which resolves Urls without access to a Page/Control (another one of those features that should be in the runtime, not in the WebForms or MVC engine). You can see there's only a little bit of logic in this code that deals with potentially different load modes. I can load scripts from a Url, WebResources or - my preferred way - from CDN. Based on the static settings the scripts to embed are composed to be returned as simple string <script> tag(s). I find this extremely useful especially when I'm not connected to the internet so that I can quickly swap in a local jQuery resource instead of loading from CDN. While CDN loading with the fallback works it can be a bit slow as the CDN is probed first before the fallback kicks in. Switching quickly in one place makes this trivial. It also makes it very easy once a new version of jQuery rolls around to move up to the new version and ensure that all pages are using the new version immediately. I'm not trying to make this out as 'the' definite way to load your resources, but rather provide it here as a pointer so you can maybe apply your own logic to determine where scripts come from and how they load. You could even automate this some more by using configuration settings or reading the locations/preferences out of some sort of data/metadata store that can be dynamically updated instead via recompilation. FWIW, I use a very similar approach for loading jQuery UI and my own ww.jquery library - the same concept can be applied to any kind of script you might be loading from different locations. Hopefully some of you find this a useful addition to your toolset. Resources Google CDN for jQuery Full ControlResources Source Code ControlResource Documentation Westwind.Web NuGet This method is part of the Westwind.Web library of the West Wind Web Toolkit or you can grab the Web library from NuGet and add to your Visual Studio project. This package includes a host of Web related utilities and script support features. © Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  jQuery   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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