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• LightDM will not start after stopping it

  - by Sweeters

  I am running Ubuntu 11.10 "Oneiric Ocelot", and in trying to install the nvidia CUDA developer drivers I switched to a virtual terminal (Ctrl-Alt-F5) and stopped lightdm (installation required that no X server instance be running) through sudo service lightdm stop. Re-starting lightdm with sudo service lightdm start did not work: A couple of * Starting [...] lines where displayed, but the process hanged. (I do not remember at which point, but I think it was * Starting System V runlevel compatibility. I manually rebooted my laptop, and ever since booting seems to hang, usually around the * Starting anac(h)ronistic cron [OK] log line (not consistently at that point, though). From that point on, I seem to be able to interact with my system only through a tty session (Ctrl-Alt-F1). I've tried purging and reinstalling both lightdm and gdm, as well as selecting both as the default display managers (through sudo dpkg-reconfigure [lightdm / gdm] or by manually editing /etc/X11/default-display-manager) through both apt-get and aptitude (that shouldn't make a difference anyway) after updating the packages, but the problem persists. Some of the responses I'm getting are the following: After running sudo dpkg-reconfigure lightdm (but not ... gdm) I get the following message: dpkg-maintscript-helper:warning: environment variable DPKG_MATINSCRIPT_NAME missing dpkg-maintscript-helper:warning: environment variable DPKG_MATINSCRIPT_PACKAGE missing After trying sudo service lightdm start or sudo start lightdm I get to see the boot loading screen again but nothing changes. If I go back to the tty shell I see lightdm start/running, process <num> but ps -e | grep lightdm gives no output. After trying sudo service gdm start or sudo starg gdm I get the gdm start/running, process <num> message, and gdm-binary is supposedly an active process, but all that happens is that the screen blinks a couple of times and nothing else. Other candidate solutions that I'd found on the web included running startx but when I try that I get an error output [...] Fatal server error: no screens found [...]. Moreover, I made sure that lightdm-gtk-greeter is installed but that did not help either. Please excuse my not including complete outputs/logs; I am writing this post from another computer and it's hard to manually copy the complete logs. Also, I've seen several posts that had to do with similar problems, but either there was no fix, or the one suggested did not work for me. In closing: Please help! I very much hope to avoid re-installing Ubuntu from scratch! :) Alex @mosi I did not manage to fix the NVIDIA kernel driver as per your instructions. I should perhaps mention that I'm on a Dell XPS15 laptop with an NVIDIA Optimus graphics card, and that I have bumblebee installed (which installs nvidia drivers during its installation, I believe). Issuing the mentioned commands I get the following: ~$uname -r 3.0.0-12-generic ~$lsmod | grep -i nvidia nvidia 11713772 0 ~$dmesg | grep -i nvidia [ 8.980041] nvidia: module license 'NVIDIA' taints kernel. [ 9.354860] nvidia 0000:01:00.0: power state changed by ACPI to D0 [ 9.354864] nvidia 0000:01:00.0: power state changed by ACPI to D0 [ 9.354868] nvidia 0000:01:00.0: enabling device (0006 -> 0007) [ 9.354873] nvidia 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 [ 9.354879] nvidia 0000:01:00.0: setting latency timer to 64 [ 9.355052] NVRM: loading NVIDIA UNIX x86_64 Kernel Module 280.13 Wed Jul 27 16:53:56 PDT 2011 Also, running aptitude search nvidia gives me the following: p nvidia-173 - NVIDIA binary Xorg driver, kernel module a p nvidia-173-dev - NVIDIA binary Xorg driver development file p nvidia-173-updates - NVIDIA binary Xorg driver, kernel module a p nvidia-173-updates-dev - NVIDIA binary Xorg driver development file p nvidia-96 - NVIDIA binary Xorg driver, kernel module a p nvidia-96-dev - NVIDIA binary Xorg driver development file p nvidia-96-updates - NVIDIA binary Xorg driver, kernel module a p nvidia-96-updates-dev - NVIDIA binary Xorg driver development file p nvidia-cg-toolkit - Cg Toolkit - GPU Shader Authoring Language p nvidia-common - Find obsolete NVIDIA drivers i nvidia-current - NVIDIA binary Xorg driver, kernel module a p nvidia-current-dev - NVIDIA binary Xorg driver development file c nvidia-current-updates - NVIDIA binary Xorg driver, kernel module a p nvidia-current-updates-dev - NVIDIA binary Xorg driver development file i nvidia-settings - Tool of configuring the NVIDIA graphics dr p nvidia-settings-updates - Tool of configuring the NVIDIA graphics dr v nvidia-va-driver - v nvidia-va-driver - I've tried manually installing (sudo aptitude install <package>) packages nvidia-common and nvidia-settings-updates but to no avail. For example, sudo aptitude install nvidia-settings-updates returns the following log: Reading package lists... Building dependency tree... Reading state information... Reading extended state information... Initializing package states... Writing extended state information... No packages will be installed, upgraded, or removed. 0 packages upgraded, 0 newly installed, 0 to remove and 83 not upgraded. Need to get 0 B of archives. After unpacking 0 B will be used. Writing extended state information... Reading package lists... Building dependency tree... Reading state information... Reading extended state information... Initializing package states... Writing extended state information... The same happens with the Linux headers (i.e. I cannot seem to be able to install linux-headers-3.0.0-12-generic). The output of aptitude search linux-headers is as follows: v linux-headers - v linux-headers - v linux-headers-2.6 - i linux-headers-2.6.38-11 - Header files related to Linux kernel versi i linux-headers-2.6.38-11-generic - Linux kernel headers for version 2.6.38 on i A linux-headers-2.6.38-8 - Header files related to Linux kernel versi i A linux-headers-2.6.38-8-generic - Linux kernel headers for version 2.6.38 on v linux-headers-3 - v linux-headers-3.0 - v linux-headers-3.0 - i A linux-headers-3.0.0-12 - Header files related to Linux kernel versi p linux-headers-3.0.0-12-generic - Linux kernel headers for version 3.0.0 on p linux-headers-3.0.0-12-generic- - Linux kernel headers for version 3.0.0 on p linux-headers-3.0.0-12-server - Linux kernel headers for version 3.0.0 on p linux-headers-3.0.0-12-virtual - Linux kernel headers for version 3.0.0 on p linux-headers-generic - Generic Linux kernel headers p linux-headers-generic-pae - Generic Linux kernel headers v linux-headers-lbm - v linux-headers-lbm - v linux-headers-lbm-2.6 - v linux-headers-lbm-2.6 - p linux-headers-lbm-3.0.0-12-gene - Header files related to linux-backports-mo p linux-headers-lbm-3.0.0-12-gene - Header files related to linux-backports-mo p linux-headers-lbm-3.0.0-12-serv - Header files related to linux-backports-mo p linux-headers-server - Linux kernel headers on Server Equipment. p linux-headers-virtual - Linux kernel headers for virtual machines @heartsmagic I did try purging and reinstalling any nvidia driver packages, but it did not seem to make a difference, My xorg.conf file contains the following: # nvidia-xconfig: X configuration file generated by nvidia-xconfig # nvidia-xconfig: version 280.13 ([email protected]) Wed Jul 27 17:15:58 PDT 2011 Section "ServerLayout" Identifier "Layout0" Screen 0 "Screen0" 0 0 InputDevice "Keyboard0" "CoreKeyboard" InputDevice "Mouse0" "CorePointer" EndSection Section "Files" EndSection Section "InputDevice" # generated from default Identifier "Mouse0" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/psaux" Option "Emulate3Buttons" "no" Option "ZAxisMapping" "4 5" EndSection Section "InputDevice" # generated from default Identifier "Keyboard0" Driver "kbd" EndSection Section "Monitor" Identifier "Monitor0" VendorName "Unknown" ModelName "Unknown" HorizSync 28.0 - 33.0 VertRefresh 43.0 - 72.0 Option "DPMS" EndSection Section "Device" Identifier "Device0" Driver "nvidia" VendorName "NVIDIA Corporation" EndSection Section "Screen" Identifier "Screen0" Device "Device0" Monitor "Monitor0" DefaultDepth 24 SubSection "Display" Depth 24 EndSubSection EndSection

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• Fragmented Log files could be slowing down your database

  - by Fatherjack

  Something that is sometimes forgotten by a lot of DBAs is the fact that database log files get fragmented in the same way that you get fragmentation in a data file. The cause is very different but the effect is the same – too much effort reading and writing data. Data files get fragmented as data is changed through normal system activity, INSERTs, UPDATEs and DELETEs cause fragmentation and most experienced DBAs are monitoring their indexes for fragmentation and dealing with it accordingly. However, you don’t hear about so many working on their log files. How can a log file get fragmented? I’m glad you asked. When you create a database there are at least two files created on the disk storage; an mdf for the data and an ldf for the log file (you can also have ndf files for extra data storage but that’s off topic for now). It is wholly possible to have more than one log file but in most cases there is little point in creating more than one as the log file is written to in a ‘wrap-around’ method (more on that later). When a log file is created at the time that a database is created the file is actually sub divided into a number of virtual log files (VLFs). The number and size of these VLFs depends on the size chosen for the log file. VLFs are also created in the space added to a log file when a log file growth event takes place. Do you have your log files set to auto grow? Then you have potentially been introducing many VLFs into your log file. Let’s get to see how many VLFs we have in a brand new database. USE master GO CREATE DATABASE VLF_Test ON ( NAME = VLF_Test, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test.mdf', SIZE = 100, MAXSIZE = 500, FILEGROWTH = 50 ) LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 5MB, MAXSIZE = 250MB, FILEGROWTH = 5MB ); go USE VLF_Test go DBCC LOGINFO; The results of this are firstly a new database is created with specified files sizes and the the DBCC LOGINFO results are returned to the script editor. The DBCC LOGINFO results have plenty of interesting information in them but lets first note there are 4 rows of information, this relates to the fact that 4 VLFs have been created in the log file. The values in the FileSize column are the sizes of each VLF in bytes, you will see that the last one to be created is slightly larger than the others. So, a 5MB log file has 4 VLFs of roughly 1.25 MB. Lets alter the CREATE DATABASE script to create a log file that’s a bit bigger and see what happens. Alter the code above so that the log file details are replaced by LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 1GB, MAXSIZE = 25GB, FILEGROWTH = 1GB ); With a bigger log file specified we get more VLFs What if we make it bigger again? LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 5GB, MAXSIZE = 250GB, FILEGROWTH = 5GB ); This time we see more VLFs are created within our log file. We now have our 5GB log file comprised of 16 files of 320MB each. In fact these sizes fall into all the ranges that control the VLF creation criteria – what a coincidence! The rules that are followed when a log file is created or has it’s size increased are pretty basic. If the file growth is lower than 64MB then 4 VLFs are created If the growth is between 64MB and 1GB then 8 VLFs are created If the growth is greater than 1GB then 16 VLFs are created. Now the potential for chaos comes if the default values and settings for log file growth are used. By default a database log file gets a 1MB log file with unlimited growth in steps of 10%. The database we just created is 6 MB, let’s add some data and see what happens. USE vlf_test go -- we need somewhere to put the data so, a table is in order IF OBJECT_ID('A_Table') IS NOT NULL DROP TABLE A_Table go CREATE TABLE A_Table ( Col_A int IDENTITY, Col_B CHAR(8000) ) GO -- Let's check the state of the log file -- 4 VLFs found EXECUTE ('DBCC LOGINFO'); go -- We can go ahead and insert some data and then check the state of the log file again INSERT A_Table (col_b) SELECT TOP 500 REPLICATE('a',2000) FROM sys.columns AS sc, sys.columns AS sc2 GO -- insert 500 rows and we get 22 VLFs EXECUTE ('DBCC LOGINFO'); go -- Let's insert more rows INSERT A_Table (col_b) SELECT TOP 2000 REPLICATE('a',2000) FROM sys.columns AS sc, sys.columns AS sc2 GO 10 -- insert 2000 rows, in 10 batches and we suddenly have 107 VLFs EXECUTE ('DBCC LOGINFO'); Well, that escalated quickly! Our log file is split, internally, into 107 fragments after a few thousand inserts. The same happens with any logged transactions, I just chose to illustrate this with INSERTs. Having too many VLFs can cause performance degradation at times of database start up, log backup and log restore operations so it’s well worth keeping a check on this property. How do we prevent excessive VLF creation? Creating the database with larger files and also with larger growth steps and actively choosing to grow your databases rather than leaving it to the Auto Grow event can make sure that the growths are made with a size that is optimal. How do we resolve a situation of a database with too many VLFs? This process needs to be done when the database is under little or no stress so that you don’t affect system users. The steps are: BACKUP LOG YourDBName TO YourBackupDestinationOfChoice Shrink the log file to its smallest possible size DBCC SHRINKFILE(FileNameOfTLogHere, TRUNCATEONLY) * Re-size the log file to the size you want it to, taking in to account your expected needs for the coming months or year. ALTER DATABASE YourDBName MODIFY FILE ( NAME = FileNameOfTLogHere, SIZE = TheSizeYouWantItToBeIn_MB) * – If you don’t know the file name of your log file then run sp_helpfile while you are connected to the database that you want to work on and you will get the details you need. The resize step can take quite a while This is already detailed far better than I can explain it by Kimberley Tripp in her blog 8-Steps-to-better-Transaction-Log-throughput.aspx. The result of this will be a log file with a VLF count according to the bullet list above. Knowing when VLFs are being created By complete coincidence while I have been writing this blog (it’s been quite some time from it’s inception to going live) Jonathan Kehayias from SQLSkills.com has written a great article on how to track database file growth using Event Notifications and Service Broker. I strongly recommend taking a look at it as this is going to catch any sneaky auto grows that take place and let you know about them right away. Hassle free monitoring of VLFs If you are lucky or wise enough to be using SQL Monitor or another monitoring tool that let’s you write your own custom metrics then you can keep an eye on this very easily. There is a custom metric for VLFs (written by Stuart Ainsworth) already on the site and there are some others there are very useful so take a moment or two to look around while you are there. Resources MSDN – http://msdn.microsoft.com/en-us/library/ms179355(v=sql.105).aspx Kimberly Tripp from SQLSkills.com – http://www.sqlskills.com/BLOGS/KIMBERLY/post/8-Steps-to-better-Transaction-Log-throughput.aspx Thomas LaRock at Simple-Talk.com – http://www.simple-talk.com/sql/database-administration/monitoring-sql-server-virtual-log-file-fragmentation/ Disclosure I am a Friend of Red Gate. This means that I am more than likely to say good things about Red Gate DBA and Developer tools. No matter how awesome I make them sound, take the time to compare them with other products before you contact the Red Gate sales team to make your order.

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• CodePlex Daily Summary for Saturday, April 03, 2010

  CodePlex Daily Summary for Saturday, April 03, 2010New ProjectsASP.NET MVC Demo: aspnetmvcdemoClasslessInterDomainRouting: ClasslessInterDomainRouting provides a class that is designed to detail with CIDR requests and ranges, it is developed within the C# Langauge and f...ClientSideRefactor: Plugin for Visual Studio.ColinTest: ColinTestePMS: An educational project to learn ASP.Net MVC, entity framework using vs 2010Extensible ASP.NET: Extensible Framework on top of ASP.NET - infrastructure level. Uses MEF for extensibility.Franchise Computing Model: Franchise Computing is a client-centric, contract-oriented, consumption-based computing model. Its framework allows service providers and consumers...GameEngine ReactorFX: Set of tools and code snippets for creation DirectX based games. Also provides a number of ideas, algorythms and problem-solutions.It's All Just Ones And Zeros: Utility code libraries for Vault API developers.Live Writer Picasa Plugin: Live Writer Picasa Plugin is a plugin for Windows Live Writer that allows you to embed photos from your Picasa Web Albums into your blog posts. Liv...Managed SDK for Meizu Cell Phone: The goal of this project is to deliver an open source managed SDK for Meizu cell phones, currently for M8. Media Player Field Type: Display a media player in a column of you document library. The library can contain movie files of diferent formats. The player will appear in the ...praca magisterska: This is my thesis: Algebraical aspects of modern cryptography,Pyx: An experimental programming language for statistics.SharpHydroLiDAR: A C# version of Lidar Hydrographic ExtractionSql Server Mds Destination: SSIS destination transform component for SQL Server Master Data ServicesStackOverflow.Net: A C# library for the StackOverflow API (currently in beta). Provides methods for every call currently in the StackOverflow API.TRX Merger Utility: People working on test projects that involve test management and execution from Visual Studio Team System 2008 and who do not have a TFS server for...UniPlanner: The UniPlanner project goal is to develop a web application able to visualize and schedule a university timetable.WikiNETParser: Wiki .NET Parser, Open Source project powered by ANTLR. Syntax defined in 3(4) files Lexer, Grammar, AST Parser.New ReleasesaaronERP builder - a framework to create customized ERP solutions: aaronERP_0.4.0.0: Changes (compared to version 0.3.0.0) : Businesslayer : - Caching of data-tables - ITranslatable Interface for mutli-language DAOs Web-Frontend: ...BatterySaver: Version 0.5: Add support for executing a power state event manually (Issue) Add support for battery percentage thresholds (Issue)ColinTest: asdfzxcv: asdfasdfComposer: V1.0.402.2001 Beta: Minor bug fixes Minor changes in interfaces Added documentation to the setup packageDynamic Configuration: Dynamic Configuration Release 2: Added ConfigurationChanged event fired whenever changes in .config file detected. Improved file watching filtering.Facebook Developer Toolkit: Version 3.1 BETA: Lots of bug fixes. Issues addressed: http://facebooktoolkit.codeplex.com/WorkItem/View.aspx?WorkItemId=14808 http://facebooktoolkit.codeplex.com/W...iExporter - iTunes playlist exporting: iExporter gui v2.5.0.0 - console v1.2.1.0: Paypal donate! New features and redesign for iExporter Gui You can now select/deselect all visible items with one click in the overview When yo...Line Counter: 1.5.5: The Line Counter is a tool to calculate lines of your code files. The tool was written in .NET 2.0. Line Counter 1.5.5 Fixed bugs in C# counter an...Live Writer Picasa Plugin: Live Writer Picasa Plugin 1.0.0: Changelog Since this is the first version there are no changes.Media Player Field Type: Media Player Field Type v1.0: Display a media player in a column of you document library. The library can contain movie files of diferent formats. The player will appear in the ...Numina Application/Security Framework: Numina.Framework Core 49601: Added .LESS library for CSS Updated default style and logo Added a few methods and method overloads to the .NET libraryOver Store: OverStore 1.16.0.0: Version 1.16.0.0 Runtime components uses PersistingRuntimeException instead of many exception types. PersistingRuntimeException message includes...patterns & practices Web Client Developer Guidance: Web Client Software Factory 2010 beta source code: The Web Client Software Factory 2010 provides an integrated set of guidance that assists architects and developers in creating web client applicati...SCSI Interface for Multimedia and Block Devices: Release 12 - View CD-DVD Drive Features: Changes in this version: - Added the ability to view the features of a CD/DVD device (e.g.: what discs it supports, whether it supports Mount Raini...SharePoint Labs: SPLab5006A-FRA-Level100: SPLab5006A-FRA-Level100 This SharePoint Lab will teach you how to create a Feature within Visual Studio, how to brand it, how to incorporate ressou...SharePoint Labs: SPLab5007A-FRA-Level300: SPLab5007A-FRA-Level300 This SharePoint Lab will teach you how to create a reusable and distributable project model for developping Features within...SharePoint Labs: SPLab5008A-FRA-Level100: SPLab5008A-FRA-Level100 This SharePoint Lab will teach you how to add an option in the ECB menu (Edit Control Block) only for specific file types w...SharePoint Labs: SPLab5009A-FRA-Level100: SPLab5009A-FRA-Level100 This SharePoint Lab will teach you the "Site Pages" model and the differences between customized/uncustomized pages (ghoste...SharePoint Labs: SPLab5010A-FRA-Level100: SPLab5010A-FRA-Level100 This SharePoint Lab will teach you the "Application Pages" model and the differences between "Site Pages" and "Application ...SharePoint Labs: SPLab5011A-FRA-Level100: SPLab5011A-FRA-Level100 This SharePoint Lab will teach you how to create a basic Application Page in the 12\TEMPLATE\LAYOUTS. Lab Language : French...sPATCH: sPatch v0.9b: + Fixed: an issue most webservers need leading slash to return filestreamsTASKedit: sTASKedit (pre-Alpha Release): This release is only for playing around, currently not useful Supported Files:Open 1.3.6 client tasks.data Export to 1.3.6 client tasks.data E...TRX Merger Utility: TRX Merger v1.0: First versionttgLib: ttgLib-0.01-beta1: In beta-version we've implemented basic functionality of ttgLib - now it can solve various problems using CPU+GPU bundle. Most important things: ...WikiNETParser: Wiki .NET Parser 2.5: Wiki .NET Parser 2.5 The documentation, binaries and source code could be downloaded from http://catarsa.com portal The latest release to downloa...WPF Zen Garden: Release 1.0: This is the first release.XNA 3D World Studio Content Pipeline: XNA 3DWS Content Pipeline - R2: This version adds terrains and brush based modelsMost Popular ProjectsRawrWBFS ManagerMicrosoft SQL Server Product Samples: DatabaseASP.NET Ajax LibrarySilverlight ToolkitAJAX Control ToolkitWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesDotNetNuke® Community EditionMost Active ProjectsGraffiti CMSRawrjQuery Library for SharePoint Web ServicesFacebook Developer ToolkitBlogEngine.NETN2 CMSBase Class LibrariesFarseer Physics EngineLINQ to TwitterMicrosoft Biology Foundation

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• Wrapping ASP.NET Client Callbacks

  - by Ricardo Peres

  Client Callbacks are probably the less known (and I dare say, less loved) of all the AJAX options in ASP.NET, which also include the UpdatePanel, Page Methods and Web Services. The reason for that, I believe, is it’s relative complexity: Get a reference to a JavaScript function; Dynamically register function that calls the above reference; Have a JavaScript handler call the registered function. However, it has some the nice advantage of being self-contained, that is, doesn’t need additional files, such as web services, JavaScript libraries, etc, or static methods declared on a page, or any kind of attributes. So, here’s what I want to do: Have a DOM element which exposes a method that is executed server side, passing it a string and returning a string; Have a server-side event that handles the client-side call; Have two client-side user-supplied callback functions for handling the success and error results. I’m going to develop a custom control without user interface that does the registration of the client JavaScript method as well as a server-side event that can be hooked by some handler on a page. My markup will look like this: 1: <script type="text/javascript"> 1:  2:  3: function onCallbackSuccess(result, context) 4: { 5: } 6:  7: function onCallbackError(error, context) 8: { 9: } 10:  </script> 2: <my:CallbackControl runat="server" ID="callback" SendAllData="true" OnCallback="OnCallback"/> The control itself looks like this: 1: public class CallbackControl : Control, ICallbackEventHandler 2: { 3: #region Public constructor 4: public CallbackControl() 5: { 6: this.SendAllData = false; 7: this.Async = true; 8: } 9: #endregion 10:  11: #region Public properties and events 12: public event EventHandler<CallbackEventArgs> Callback; 13:  14: [DefaultValue(true)] 15: public Boolean Async 16: { 17: get; 18: set; 19: } 20:  21: [DefaultValue(false)] 22: public Boolean SendAllData 23: { 24: get; 25: set; 26: } 27:  28: #endregion 29:  30: #region Protected override methods 31:  32: protected override void Render(HtmlTextWriter writer) 33: { 34: writer.AddAttribute(HtmlTextWriterAttribute.Id, this.ClientID); 35: writer.RenderBeginTag(HtmlTextWriterTag.Span); 36:  37: base.Render(writer); 38:  39: writer.RenderEndTag(); 40: } 41:  42: protected override void OnInit(EventArgs e) 43: { 44: String reference = this.Page.ClientScript.GetCallbackEventReference(this, "arg", "onCallbackSuccess", "context", "onCallbackError", this.Async); 45: String script = String.Concat("\ndocument.getElementById('", this.ClientID, "').callback = function(arg, context, onCallbackSuccess, onCallbackError){", ((this.SendAllData == true) ? "__theFormPostCollection.length = 0; __theFormPostData = ''; WebForm_InitCallback(); " : String.Empty), reference, ";};\n"); 46:  47: this.Page.ClientScript.RegisterStartupScript(this.GetType(), String.Concat("callback", this.ClientID), script, true); 48:  49: base.OnInit(e); 50: } 51:  52: #endregion 53:  54: #region Protected virtual methods 55: protected virtual void OnCallback(CallbackEventArgs args) 56: { 57: EventHandler<CallbackEventArgs> handler = this.Callback; 58:  59: if (handler != null) 60: { 61: handler(this, args); 62: } 63: } 64:  65: #endregion 66:  67: #region ICallbackEventHandler Members 68:  69: String ICallbackEventHandler.GetCallbackResult() 70: { 71: CallbackEventArgs args = new CallbackEventArgs(this.Context.Items["Data"] as String); 72:  73: this.OnCallback(args); 74:  75: return (args.Result); 76: } 77:  78: void ICallbackEventHandler.RaiseCallbackEvent(String eventArgument) 79: { 80: this.Context.Items["Data"] = eventArgument; 81: } 82:  83: #endregion 84: } And the event argument class: 1: [Serializable] 2: public class CallbackEventArgs : EventArgs 3: { 4: public CallbackEventArgs(String argument) 5: { 6: this.Argument = argument; 7: this.Result = String.Empty; 8: } 9:  10: public String Argument 11: { 12: get; 13: private set; 14: } 15:  16: public String Result 17: { 18: get; 19: set; 20: } 21: } You will notice two properties on the CallbackControl: Async: indicates if the call should be made asynchronously or synchronously (the default); SendAllData: indicates if the callback call will include the view and control state of all of the controls on the page, so that, on the server side, they will have their properties set when the Callback event is fired. The CallbackEventArgs class exposes two properties: Argument: the read-only argument passed to the client-side function; Result: the result to return to the client-side callback function, set from the Callback event handler. An example of an handler for the Callback event would be: 1: protected void OnCallback(Object sender, CallbackEventArgs e) 2: { 3: e.Result = String.Join(String.Empty, e.Argument.Reverse()); 4: } Finally, in order to fire the Callback event from the client, you only need this: 1: <input type="text" id="input"/> 2: <input type="button" value="Get Result" onclick="document.getElementById('callback').callback(callback(document.getElementById('input').value, 'context', onCallbackSuccess, onCallbackError))"/> The syntax of the callback function is: arg: some string argument; context: some context that will be passed to the callback functions (success or failure); callbackSuccessFunction: some function that will be called when the callback succeeds; callbackFailureFunction: some function that will be called if the callback fails for some reason. Give it a try and see if it helps!

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• C#: Optional Parameters - Pros and Pitfalls

  - by James Michael Hare

  When Microsoft rolled out Visual Studio 2010 with C# 4, I was very excited to learn how I could apply all the new features and enhancements to help make me and my team more productive developers. Default parameters have been around forever in C++, and were intentionally omitted in Java in favor of using overloading to satisfy that need as it was though that having too many default parameters could introduce code safety issues.  To some extent I can understand that move, as I’ve been bitten by default parameter pitfalls before, but at the same time I feel like Java threw out the baby with the bathwater in that move and I’m glad to see C# now has them. This post briefly discusses the pros and pitfalls of using default parameters.  I’m avoiding saying cons, because I really don’t believe using default parameters is a negative thing, I just think there are things you must watch for and guard against to avoid abuses that can cause code safety issues. Pro: Default Parameters Can Simplify Code Let’s start out with positives.  Consider how much cleaner it is to reduce all the overloads in methods or constructors that simply exist to give the semblance of optional parameters.  For example, we could have a Message class defined which allows for all possible initializations of a Message: 1: public class Message 2: { 3: // can either cascade these like this or duplicate the defaults (which can introduce risk) 4: public Message() 5: : this(string.Empty) 6: { 7: } 8:  9: public Message(string text) 10: : this(text, null) 11: { 12: } 13:  14: public Message(string text, IDictionary<string, string> properties) 15: : this(text, properties, -1) 16: { 17: } 18:  19: public Message(string text, IDictionary<string, string> properties, long timeToLive) 20: { 21: // ... 22: } 23: }   Now consider the same code with default parameters: 1: public class Message 2: { 3: // can either cascade these like this or duplicate the defaults (which can introduce risk) 4: public Message(string text = "", IDictionary<string, string> properties = null, long timeToLive = -1) 5: { 6: // ... 7: } 8: }   Much more clean and concise and no repetitive coding!  In addition, in the past if you wanted to be able to cleanly supply timeToLive and accept the default on text and properties above, you would need to either create another overload, or pass in the defaults explicitly.  With named parameters, though, we can do this easily: 1: var msg = new Message(timeToLive: 100);   Pro: Named Parameters can Improve Readability I must say one of my favorite things with the default parameters addition in C# is the named parameters.  It lets code be a lot easier to understand visually with no comments.  Think how many times you’ve run across a TimeSpan declaration with 4 arguments and wondered if they were passing in days/hours/minutes/seconds or hours/minutes/seconds/milliseconds.  A novice running through your code may wonder what it is.  Named arguments can help resolve the visual ambiguity: 1: // is this days/hours/minutes/seconds (no) or hours/minutes/seconds/milliseconds (yes) 2: var ts = new TimeSpan(1, 2, 3, 4); 3:  4: // this however is visually very explicit 5: var ts = new TimeSpan(days: 1, hours: 2, minutes: 3, seconds: 4);   Or think of the times you’ve run across something passing a Boolean literal and wondered what it was: 1: // what is false here? 2: var sub = CreateSubscriber(hostname, port, false); 3:  4: // aha! Much more visibly clear 5: var sub = CreateSubscriber(hostname, port, isBuffered: false);   Pitfall: Don't Insert new Default Parameters In Between Existing Defaults Now let’s consider a two potential pitfalls.  The first is really an abuse.  It’s not really a fault of the default parameters themselves, but a fault in the use of them.  Let’s consider that Message constructor again with defaults.  Let’s say you want to add a messagePriority to the message and you think this is more important than a timeToLive value, so you decide to put messagePriority before it in the default, this gives you: 1: public class Message 2: { 3: public Message(string text = "", IDictionary<string, string> properties = null, int priority = 5, long timeToLive = -1) 4: { 5: // ... 6: } 7: }   Oh boy have we set ourselves up for failure!  Why?  Think of all the code out there that could already be using the library that already specified the timeToLive, such as this possible call: 1: var msg = new Message(“An error occurred”, myProperties, 1000);   Before this specified a message with a TTL of 1000, now it specifies a message with a priority of 1000 and a time to live of -1 (infinite).  All of this with NO compiler errors or warnings. So the rule to take away is if you are adding new default parameters to a method that’s currently in use, make sure you add them to the end of the list or create a brand new method or overload. Pitfall: Beware of Default Parameters in Inheritance and Interface Implementation Now, the second potential pitfalls has to do with inheritance and interface implementation.  I’ll illustrate with a puzzle: 1: public interface ITag 2: { 3: void WriteTag(string tagName = "ITag"); 4: } 5:  6: public class BaseTag : ITag 7: { 8: public virtual void WriteTag(string tagName = "BaseTag") { Console.WriteLine(tagName); } 9: } 10:  11: public class SubTag : BaseTag 12: { 13: public override void WriteTag(string tagName = "SubTag") { Console.WriteLine(tagName); } 14: } 15:  16: public static class Program 17: { 18: public static void Main() 19: { 20: SubTag subTag = new SubTag(); 21: BaseTag subByBaseTag = subTag; 22: ITag subByInterfaceTag = subTag; 23:  24: // what happens here? 25: subTag.WriteTag(); 26: subByBaseTag.WriteTag(); 27: subByInterfaceTag.WriteTag(); 28: } 29: }   What happens?  Well, even though the object in each case is SubTag whose tag is “SubTag”, you will get: 1: SubTag 2: BaseTag 3: ITag   Why?  Because default parameter are resolved at compile time, not runtime!  This means that the default does not belong to the object being called, but by the reference type it’s being called through.  Since the SubTag instance is being called through an ITag reference, it will use the default specified in ITag. So the moral of the story here is to be very careful how you specify defaults in interfaces or inheritance hierarchies.  I would suggest avoiding repeating them, and instead concentrating on the layer of classes or interfaces you must likely expect your caller to be calling from. For example, if you have a messaging factory that returns an IMessage which can be either an MsmqMessage or JmsMessage, it only makes since to put the defaults at the IMessage level since chances are your user will be using the interface only. So let’s sum up.  In general, I really love default and named parameters in C# 4.0.  I think they’re a great tool to help make your code easier to read and maintain when used correctly. On the plus side, default parameters: Reduce redundant overloading for the sake of providing optional calling structures. Improve readability by being able to name an ambiguous argument. But remember to make sure you: Do not insert new default parameters in the middle of an existing set of default parameters, this may cause unpredictable behavior that may not necessarily throw a syntax error – add to end of list or create new method. Be extremely careful how you use default parameters in inheritance hierarchies and interfaces – choose the most appropriate level to add the defaults based on expected usage. Technorati Tags: C#,.NET,Software,Default Parameters

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• C#/.NET Little Wonders: Using &lsquo;default&rsquo; to Get Default Values

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Today’s little wonder is another of those small items that can help a lot in certain situations, especially when writing generics.  In particular, it is useful in determining what the default value of a given type would be. The Problem: what’s the default value for a generic type? There comes a time when you’re writing generic code where you may want to set an item of a given generic type.  Seems simple enough, right?  We’ll let’s see! Let’s say we want to query a Dictionary<TKey, TValue> for a given key and get back the value, but if the key doesn’t exist, we’d like a default value instead of throwing an exception. So, for example, we might have a the following dictionary defined: 1: var lookup = new Dictionary<int, string> 2: { 3: { 1, "Apple" }, 4: { 2, "Orange" }, 5: { 3, "Banana" }, 6: { 4, "Pear" }, 7: { 9, "Peach" } 8: }; And using those definitions, perhaps we want to do something like this: 1: // assume a default 2: string value = "Unknown"; 3:  4: // if the item exists in dictionary, get its value 5: if (lookup.ContainsKey(5)) 6: { 7: value = lookup[5]; 8: } But that’s inefficient, because then we’re double-hashing (once for ContainsKey() and once for the indexer).  Well, to avoid the double-hashing, we could use TryGetValue() instead: 1: string value; 2:  3: // if key exists, value will be put in value, if not default it 4: if (!lookup.TryGetValue(5, out value)) 5: { 6: value = "Unknown"; 7: } But the “flow” of using of TryGetValue() can get clunky at times when you just want to assign either the value or a default to a variable.  Essentially it’s 3-ish lines (depending on formatting) for 1 assignment.  So perhaps instead we’d like to write an extension method to support a cleaner interface that will return a default if the item isn’t found: 1: public static class DictionaryExtensions 2: { 3: public static TValue GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dict, 4: TKey key, TValue defaultIfNotFound) 5: { 6: TValue value; 7:  8: // value will be the result or the default for TValue 9: if (!dict.TryGetValue(key, out value)) 10: { 11: value = defaultIfNotFound; 12: } 13:  14: return value; 15: } 16: } 17:  So this creates an extension method on Dictionary<TKey, TValue> that will attempt to get a value using the given key, and will return the defaultIfNotFound as a stand-in if the key does not exist. This code compiles, fine, but what if we would like to go one step further and allow them to specify a default if not found, or accept the default for the type?  Obviously, we could overload the method to take the default or not, but that would be duplicated code and a bit heavy for just specifying a default.  It seems reasonable that we could set the not found value to be either the default for the type, or the specified value. So what if we defaulted the type to null? 1: public static TValue GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dict, 2: TKey key, TValue defaultIfNotFound = null) // ... No, this won’t work, because only reference types (and Nullable<T> wrapped types due to syntactical sugar) can be assigned to null.  So what about a calling parameterless constructor? 1: public static TValue GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dict, 2: TKey key, TValue defaultIfNotFound = new TValue()) // ... No, this won’t work either for several reasons.  First, we’d expect a reference type to return null, not an “empty” instance.  Secondly, not all reference types have a parameter-less constructor (string for example does not).  And finally, a constructor cannot be determined at compile-time, while default values can. The Solution: default(T) – returns the default value for type T Many of us know the default keyword for its uses in switch statements as the default case.  But it has another use as well: it can return us the default value for a given type.  And since it generates the same defaults that default field initialization uses, it can be determined at compile-time as well. For example: 1: var x = default(int); // x is 0 2:  3: var y = default(bool); // y is false 4:  5: var z = default(string); // z is null 6:  7: var t = default(TimeSpan); // t is a TimeSpan with Ticks == 0 8:  9: var n = default(int?); // n is a Nullable<int> with HasValue == false Notice that for numeric types the default is 0, and for reference types the default is null.  In addition, for struct types, the value is a default-constructed struct – which simply means a struct where every field has their default value (hence 0 Ticks for TimeSpan, etc.). So using this, we could modify our code to this: 1: public static class DictionaryExtensions 2: { 3: public static TValue GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dict, 4: TKey key, TValue defaultIfNotFound = default(TValue)) 5: { 6: TValue value; 7:  8: // value will be the result or the default for TValue 9: if (!dict.TryGetValue(key, out value)) 10: { 11: value = defaultIfNotFound; 12: } 13:  14: return value; 15: } 16: } Now, if defaultIfNotFound is unspecified, it will use default(TValue) which will be the default value for whatever value type the dictionary holds.  So let’s consider how we could use this: 1: lookup.GetValueOrDefault(1); // returns “Apple” 2:  3: lookup.GetValueOrDefault(5); // returns null 4:  5: lookup.GetValueOrDefault(5, “Unknown”); // returns “Unknown” 6:  Again, do not confuse a parameter-less constructor with the default value for a type.  Remember that the default value for any type is the compile-time default for any instance of that type (0 for numeric, false for bool, null for reference types, and struct will all default fields for struct).  Consider the difference: 1: // both zero 2: int i1 = default(int); 3: int i2 = new int(); 4:  5: // both “zeroed” structs 6: var dt1 = default(DateTime); 7: var dt2 = new DateTime(); 8:  9: // sb1 is null, sb2 is an “empty” string builder 10: var sb1 = default(StringBuilder()); 11: var sb2 = new StringBuilder(); So in the above code, notice that the value types all resolve the same whether using default or parameter-less construction.  This is because a value type is never null (even Nullable<T> wrapped types are never “null” in a reference sense), they will just by default contain fields with all default values. However, for reference types, the default is null and not a constructed instance.  Also it should be noted that not all classes have parameter-less constructors (string, for instance, doesn’t have one – and doesn’t need one). Summary Whenever you need to get the default value for a type, especially a generic type, consider using the default keyword.  This handy word will give you the default value for the given type at compile-time, which can then be used for initialization, optional parameters, etc. Technorati Tags: C#,CSharp,.NET,Little Wonders,default

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• And What's Your Brand Worth? ...anything?

  - by [email protected]

  100 Best Global Brands from Business Week Story: The Great Trust Offensive Slide Show: Top Brands 2009 Methodology: Picking the Winners The recession has presented marketing executives around the world with the toughest test of their careers. Some brands have prospered amid the hard times--or at least held their own. Others have slipped a surprising number of places on our ninth annual ranking, compiled by consultancy Interbrand. But for seven brands, impressive performances saw them race up the charts to take their place on this year's list. Here are the numbers behind the rankings Rank 2009 Rank 2008 Employer 2009 Brand value($millions) 2008 Brand value($millions) Percent change(%) Country of Ownership 1 1 Coca-Cola  68,734  66,667  3 U.S. 2 2 IBM  60,211  59,031  2 U.S. 3 3 Microsoft  56,647  59,007  -4 U.S. 4 4 GE  47,777  53,086  -10 U.S. 5 5 Nokia  34,864  35,942  -3 Finland 6 8 McDonald's  32,275  31,049  4 U.S. 7 10 Google  31,980  25,590  25 U.S. 8 6 Toyota  31,330  34,050  -8 Japan 9 7 Intel  30,636  31,261  -2 U.S. 10 9 Disney  28,447  29,251  -3 U.S. 11 12 Hewlett-Packard  24,096  23,509  2 U.S. 12 11 Mercedes-Benz  23,867  25,577  -7 Germany 13 14 Gillette  22,841  22,069  4 U.S. 14 17 Cisco  22,030  21,306  3 U.S. 15 13 BMW  21,671  23,298  -7 Germany 16 16 Louis Vuitton  21,120  21,602  -2 France 17 18 Marlboro  19,010  21,300  -11 U.S. 18 20 Honda  17,803  19,079  -7 Japan 19 21 Samsung  17,518  17,689  -1 S. Korea 20 24 Apple  15,443  13,724  12 U.S. 21 22 H&M  15,375  13,840  11 Sweden 22 15 American Express  14,971  21,940  -32 U.S. 23 26 Pepsi  13,706  13,249  3 U.S. 24 23 Oracle  13,699  13,831  -1 U.S. 25 28 Nescafe  13,317  13,055  2 Switzerland 26 29 Nike  13,179  12,672  4 U.S. 27 31 SAP  12,106  12,228  -1 Germany 28 35 Ikea  12,004  10,913  10 Sweden 29 25 Sony  11,953  13,583  -12 Japan 30 33 Budweiser  11,833  11,438  3 Belgium 31 30 UPS  11,594  12,621  -8 U.S. 32 27 HSBC  10,510  13,143  -20 Britain 33 36 Canon  10,441  10,876  -4 Japan 34 39 Kellogg's  10,428  9,710  7 U.S. 35 32 Dell  10,291  11,695  -12 U.S. 36 19 Citi  10,254  20,174  -49 U.S. 37 37 JPMorgan  9,550  10,773  -11 U.S. 38 38 Goldman Sachs  9,248  10,331  -10 U.S. 39 40 Nintendo  9,210  8,772  5 Japan 40 44 Thomson Reuters  8,434  8,313  1 Canada 41 45 Gucci  8,182  8,254  -1 Italy 42 43 Philips  8,121  8,325  -2 Netherlands 43 58 Amazon  7,858  6,434  22 U.S. 44 51 L'Oreal  7,748  7,508  3 France 45 47 Accenture  7,710  7,948  -3 U.S. 46 46 eBay  7,350  7,991  -8 U.S. 47 48 Siemens  7,308  7,943  -8 Germany 48 56 Heinz  7,244  6,646  9 U.S. 49 49 Ford  7,005  7,896  -11 U.S. 50 62 Zara  6,789  5,955  14 Spain   Valuations do not represent a guarantee of future performance of the brands or companies. Data: Interbrand, BusinessWeek

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• Clustering for Mere Mortals (Pt 3)

  - by Geoff N. Hiten

  The Controller Now we get to the meat of the matter.  You want a virtual cluster, the first thing you have to do is create your own portable domain.  Start with a plain vanilla install of Windows 2003 R2 Standard on a semi-default VM. (1 GB RAM, 2 cores, 2 NICs, 128GB dynamically expanding VHD file).  I chose this because it had the smallest disk and memory footprint of any current supported Microsoft Server product.  I created the VM with a single dynamically expanding VHD, one fixed 16 GB VHD, and two NICs.  One NIC is connected to the outside world and the other one is part of an internal-only network.  The first NIC is set up as a DHCP client.  We will get to the other one later. I actually tried this with Windows 2008 R2, but it failed miserably.  Not sure whether it was 2008 R2 or the fact I tried to use cloned VMs in the cluster.  Clustering is one place where NewSID would really come in handy.  Too bad Microsoft bought and buried it. Load and Patch the OS (hence the need for the outside connection).This is a good time to go get dinner.  Maybe a movie too.  There are close to a hundred patches that need to be downloaded and applied.  Avoiding that mess was why I put so much time into trying to get the 2008 R2 version working.  Maybe next time.  Don’t forget to add the extensions for VMLite (or whatever virtualization product you prefer). Set a fixed IP address on the internal-only NIC.  Do not give it a gateway.  Put the same IP address for the NIC and for the DNS Server.  This IP should be in a range that is never available on your public network.  You will need all the addresses in the range available.  See the previous post for the exact settings I used. I chose 10.97.230.1 as the server.  The rest of the 10.97.230 range is what I will use later.  For the curious, those numbers are based on elements of my home address.  Not truly random, but good enough for this project. Do not bridge the network connections.  I never allowed the cluster nodes direct access to any public network. Format the fixed VHD and leave it alone for now. Promote the VM to a Domain Controller.  If you have never done this, don’t worry.  The only meaningful decision is what to call the new domain.  I prefer a bogus name that does not correspond to a real Top-Level Domain (TLD).  .com, .biz., .net, .org  are all TLDs that we know and love.  I chose .test as the TLD since it is descriptive AND it does not exist in the real world.  The domain is called MicroAD.  This gives me MicroAD.Test as my domain. During the promotion process, you will be prompted to install DNS as part of the Domain creation process.  You want to accept this option.  The installer will automatically assign this DNS server as the authoritative owner of the MicroAD.test DNS domain (not to be confused with the MicroAD.test Active Directory domain.) For the rest of the DCPROMO process, just accept the defaults. Now let’s make our IP address management easy.  Add the DHCP Role to the server.  Add the server (10.97.230.1 in this case) as the default gateway to assign to DHCP clients.  Here is where you have to be VERY careful and bind it ONLY to the Internal NIC.  Trust me, your network admin will NOT like an extra DHCP server “helping” out on her network.  Go ahead and create a range of 10-20 IP Addresses in your scope.  You might find other uses for a pocket domain controller <cough> Mirroring </cough> than just for building a cluster.  And Clustering in SQL 2008 and Windows 2008 R2 fully supports DHCP addresses. Now we have three of the five key roles ready.  Two more to go. Next comes file sharing.  Since your cluster node VMs will not have access to any outside, you have to have some way to get files into these VMs.  I simply go to the root of C: and create a “Shared” folder.  I then share it out and grant full control to “Everyone” to both the share and to the underlying NTFS folder.   This will be immensely useful for Service Packs, demo databases, and any other software that isn’t packaged as an ISO that we can mount to the VM. Finally we need to create a block-level multi-connect storage device.  The kind folks at Starwinds Software (http://www.starwindsoftware.com/) graciously gave me a non-expiring demo license for expressly this purpose.  Their iSCSI SAN software lets you create an iSCSI target from nearly any storage medium.  Refreshingly, their product does exactly what they say it does.  Thanks. Remember that 16 GB VHD file?  That is where we are going to carve into our LUNs.  I created an iSCSI folder off the root, just so I can keep everything organized.  I then carved 5 ea. 2 GB iSCSI targets from that folder.  I chose a fixed VHD for performance.  I tried this earlier with a dynamically expanding VHD, but too many layers of abstraction and sparseness combined to make it unusable even for a demo.  Stick with a fixed VHD so there is a one-to-one mapping between abstract and physical storage.  If you read the previous post, you know what I named these iSCSI LUNs and why.  Yes, I do have some left over space.  Always leave yourself room for future growth or options. This gets us up to where we can actually build the nodes and install SQL.  As with most clusters, the real work happens long before the individual nodes get installed and configured.  At least it does if you want the cluster to be a true high-availability platform.

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• Clustering for Mere Mortals (Pt3)

  - by Geoff N. Hiten

  The Controller Now we get to the meat of the matter.  You want a virtual cluster, the first thing you have to do is create your own portable domain.  IStart with a plain vanilla install of Windows 2003 R2 Standard on a semi-default VM. (1 GB RAM, 2 cores, 2 NICs, 128GB dynamically expanding VHD file).  I chose this because it had the smallest disk and memory footprint of any current supported Microsoft Server product.  I created the VM with a single dynamically expanding VHD, one fixed 16 GB VHD, and two NICs.  One NIC is connected to the outside world and the other one is part of an internal-only network.  The first NIC is set up as a DHCP client.  We will get to the other one later. I actually tried this with Windows 2008 R2, but it failed miserably.  Not sure whether it was 2008 R2 or the fact I tried to use cloned VMs in the cluster.  Clustering is one place where NewSID would really come in handy.  Too bad Microsoft bought and buried it. Load and Patch the OS (hence the need for the outside connection).This is a good time to go get dinner.  Maybe a movie too.  There are close to a hundred patches that need to be downloaded and applied.  Avoiding that mess was why I put so much time into trying to get the 2008 R2 version working.  Maybe next time.  Don’t forget to add the extensions for VMLite (or whatever virtualization product you prefer). Set a fixed IP address on the internal-only NIC.  Do not give it a gateway.  Put the same IP address for the NIC and for the DNS Server.  This IP should be in a range that is never available on your public network.  You will need all the addresses in the range available.  See the previous post for the exact settings I used. I chose 10.97.230.1 as the server.  The rest of the 10.97.230 range is what I will use later.  For the curious, those numbers are based on elements of my home address.  Not truly random, but good enough for this project. Do not bridge the network connections.  I never allowed the cluster nodes direct access to any public network. Format the fixed VHD and leave it alone for now. Promote the VM to a Domain Controller.  If you have never done this, don’t worry.  The only meaningful decision is what to call the new domain.  I prefer a bogus name that does not correspond to a real Top-Level Domain (TLD).  .com, .biz., .net, .org  are all TLDs that we know and love.  I chose .test as the TLD since it is descriptive AND it does not exist in the real world.  The domain is called MicroAD.  This gives me MicroAD.Test as my domain. During the promotion process, you will be prompted to install DNS as part of the Domain creation process.  You want to accept this option.  The installer will automatically assign this DNS server as the authoritative owner of the MicroAD.test DNS domain (not to be confused with the MicroAD.test Active Directory domain.) For the rest of the DCPROMO process, just accept the defaults. Now let’s make our IP address management easy.  Add the DHCP Role to the server.  Add the server (10.97.230.1 in this case) as the default gateway to assign to DHCP clients.  Here is where you have to be VERY careful and bind it ONLY to the Internal NIC.  Trust me, your network admin will NOT like an extra DHCP server “helping” out on her network.  Go ahead and create a range of 10-20 IP Addresses in your scope.  You might find other uses for a pocket domain controller <cough> Mirroring </cough> than just for building a cluster.  And Clustering in SQL 2008 and Windows 2008 R2 fully supports DHCP addresses. Now we have three of the five key roles ready.  Two more to go. Next comes file sharing.  Since your cluster node VMs will not have access to any outside, you have to have some way to get files into these VMs.  I simply go to the root of C: and create a “Shared” folder.  I then share it out and grant full control to “Everyone” to both the share and to the underlying NTFS folder.   This will be immensely useful for Service Packs, demo databases, and any other software that isn’t packaged as an ISO that we can mount to the VM. Finally we need to create a block-level multi-connect storage device.  The kind folks at Starwinds Software (http://www.starwindsoftware.com/) graciously gave me a non-expiring demo license for expressly this purpose.  Their iSCSI SAN software lets you create an iSCSI target from nearly any storage medium.  Refreshingly, their product does exactly what they say it does.  Thanks. Remember that 16 GB VHD file?  That is where we are going to carve into our LUNs.  I created an iSCSI folder off the root, just so I can keep everything organized.  I then carved 5 ea. 2 GB iSCSI targets from that folder.  I chose a fixed VHD for performance.  I tried this earlier with a dynamically expanding VHD, but too many layers of abstraction and sparseness combined to make it unusable even for a demo.  Stick with a fixed VHD so there is a one-to-one mapping between abstract and physical storage.  If you read the previous post, you know what I named these iSCSI LUNs and why.  Yes, I do have some left over space.  Always leave yourself room for future growth or options. This gets us up to where we can actually build the nodes and install SQL.  As with most clusters, the real work happens long before the individual nodes get installed and configured.  At least it does if you want the cluster to be a true high-availability platform.

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• Silverlight MEF – Download On Demand

  - by PeterTweed

  Take the Slalom Challenge at www.slalomchallenge.com! A common challenge with building complex applications in Silverlight is the initial download size of the xap file.  MEF enables us to build composable applications that allows us to build complex composite applications.  Wouldn’t it be great if we had a mechanism to spilt out components into different Silverlight applications in separate xap files and download the separate xap file only if needed?   MEF gives us the ability to do this.  This post will cover the basics needed to build such a composite application split between different silerlight applications and download the referenced silverlight application only when needed. Steps: 1.     Create a Silverlight 4 application 2.     Add references to the following assemblies: System.ComponentModel.Composition.dll System.ComponentModel.Composition.Initialization.dll 3.     Add a new Silverlight 4 application called ExternalSilverlightApplication to the solution that was created in step 1.  Ensure the new application is hosted in the web application for the solution and choose to not create a test page for the new application. 4.     Delete the App.xaml and MainPage.xaml files – they aren’t needed. 5.     Add references to the following assemblies in the ExternalSilverlightApplication project: System.ComponentModel.Composition.dll System.ComponentModel.Composition.Initialization.dll 6.     Ensure the two references above have their Copy Local values set to false.  As we will have these two assmblies in the original Silverlight application, we will have no need to include them in the built ExternalSilverlightApplication build. 7.     Add a new user control called LeftControl to the ExternalSilverlightApplication project. 8.     Replace the LayoutRoot Grid with the following xaml:     <Grid x:Name="LayoutRoot" Background="Beige" Margin="40" >         <Button Content="Left Content" Margin="30"></Button>     </Grid> 9.     Add the following statement to the top of the LeftControl.xaml.cs file using System.ComponentModel.Composition; 10.   Add the following attribute to the LeftControl class     [Export(typeof(LeftControl))]   This attribute tells MEF that the type LeftControl will be exported – i.e. made available for other applications to import and compose into the application. 11.   Add a new user control called RightControl to the ExternalSilverlightApplication project. 12.   Replace the LayoutRoot Grid with the following xaml:     <Grid x:Name="LayoutRoot" Background="Green" Margin="40"  >         <TextBlock Margin="40" Foreground="White" Text="Right Control" FontSize="16" VerticalAlignment="Center" HorizontalAlignment="Center" ></TextBlock>     </Grid> 13.   Add the following statement to the top of the RightControl.xaml.cs file using System.ComponentModel.Composition; 14.   Add the following attribute to the RightControl class     [Export(typeof(RightControl))] 15.   In your original Silverlight project add a reference to the ExternalSilverlightApplication project. 16.   Change the reference to the ExternalSilverlightApplication project to have it’s Copy Local value = false.  This will ensure that the referenced ExternalSilverlightApplication Silverlight application is not included in the original Silverlight application package when it it built.  The ExternalSilverlightApplication Silverlight application therefore has to be downloaded on demand by the original Silverlight application for it’s controls to be used. 1.     In your original Silverlight project add the following xaml to the LayoutRoot Grid in MainPage.xaml:         <Grid.RowDefinitions>             <RowDefinition Height="65*" />             <RowDefinition Height="235*" />         </Grid.RowDefinitions>         <Button Name="LoaderButton" Content="Download External Controls" Click="Button_Click"></Button>         <StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Center" >             <Border Name="LeftContent" Background="Red" BorderBrush="Gray" CornerRadius="20"></Border>             <Border Name="RightContent" Background="Red" BorderBrush="Gray" CornerRadius="20"></Border>         </StackPanel>       The borders will hold the controls that will be downlaoded, imported and composed via MEF when the button is clicked. 2.     Add the following statement to the top of the MainPage.xaml.cs file using System.ComponentModel.Composition; 3.     Add the following properties to the MainPage class:         [Import(typeof(LeftControl))]         public LeftControl LeftUserControl { get; set; }         [Import(typeof(RightControl))]         public RightControl RightUserControl { get; set; }   This defines properties accepting LeftControl and RightControl types.  The attrributes are used to tell MEF the discovered type that should be applied to the property when composition occurs. 17.   Add the following event handler for the button click to the MainPage.xaml.cs file:         private void Button_Click(object sender, RoutedEventArgs e)         {                   DeploymentCatalog deploymentCatalog =     new DeploymentCatalog("ExternalSilverlightApplication.xap");                   CompositionHost.Initialize(deploymentCatalog);                   deploymentCatalog.DownloadCompleted += (s, i) =>                 {                     if (i.Error == null)                     {                         CompositionInitializer.SatisfyImports(this);                           LeftContent.Child = LeftUserControl;                         RightContent.Child = RightUserControl;                         LoaderButton.IsEnabled = false;                     }                 };                   deploymentCatalog.DownloadAsync();         } This is where the magic happens!  The deploymentCatalog object is pointed to the ExternalSilverlightApplication.xap file.  It is then associated with the CompositionHost initialization.  As the download will be asynchronous, an eventhandler is created for the DownloadCompleted event.  The deploymentCatalog object is then told to start the asynchronous download. The event handler that executes when the download is completed uses the CompositionInitializer.SatisfyImports() function to tell MEF to satisfy the Imports for the current class.  It is at this point that the LeftUserControl and RightUserControl properties are initialized with composed objects from the downloaded ExternalSilverlightApplication.xap package. 18.   Run the application click the Download External Controls button and see the controls defined in the ExternalSilverlightApplication application loaded into the original Silverlight application. Congratulations!  You have implemented download on demand capabilities for composite applications using the MEF DeploymentCatalog class.  You are now able to segment your applications into separate xap file for deployment.

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• Hard drive mounted at / , duplicate mounted hard drive after using MountManager

  - by HellHarvest

  possible duplicate post I'm running 12.04 64bit. My system is a dual boot for both Ubuntu and Windows7. Both operating systems are sharing the drive named "Elements". My volume named "Elements" is a 1TB SATA NTFS hard drive that shows up twice in the side bar in nautilus. One of the icons is functional and even has the convenient "eject" icon next to it. Below is a picture of the left menu in Nautilus, with System Monitor-File Systems tab open on top of it. Can someone advise me about how to get rid of this extra icon? I think the problem is much more deep-rooted than just a GUI glitch on Nautilus' part. The other icon does nothing but spit out the following error when I click on it (image below). This only happened AFTER I tried using Mount Manager to automate mounting the drive at start up. I've already uninstalled Mount Manager, and restarted, but the problem didn't go away. The hard drive does mount automatically now, so I guess that's cool. But now, every time I boot up now and open Nautilus, BOTH of these icons appear, one of which is fictitious and useless. According to the image above and the outputs of several other commands, it appears to be mounted at / In which case, no matter where I am in Nautilus when I try to click on that icon, of course it will tell me that that drive is in use by another program... Nautilus. I'm afraid of trying to unmount this hard drive (sdb6) because of where it appears to be mounted. I'm kind of a noob, and I have this gut feeling that tells me trying to unmount a drive at / will destroy my entire file system. This fear was further strengthened by the output of "$ fsck" at the very bottom of this post. Error immediately below when that 2nd "Elements" hard drive is clicked in Nautilus: Unable to mount Elements Mount is denied because the NTFS volume is already exclusively opened. The volume may be already mounted, or another software may use it which could be identified for example by the help of the 'fuser' command. It's odd to me that that error message above claims that it's an NTFS volume when everything else tell me that it's an ext4 volume. The actual hard drive "Elements" is in fact an NTFS volume. Here's the output of a few commands and configuration files that may be of interest: $ fuser -a / /: 2120r 2159rc 2160rc 2172r 2178rc 2180rc 2188r 2191rc 2200rc 2203rc 2205rc 2206r 2211r 2212r 2214r 2220r 2228r 2234rc 2246rc 2249rc 2254rc 2260rc 2261r 2262r 2277rc 2287rc 2291rc 2311rc 2313rc 2332rc 2334rc 2339rc 2343rc 2344rc 2352rc 2372rc 2389rc 2422r 2490r 2496rc 2501rc 2566r 2573rc 2581rc 2589rc 2592r 2603r 2611rc 2613rc 2615rc 2678rc 2927r 2981r 3104rc 4156rc 4196rc 4206rc 4213rc 4240rc 4297rc 5032rc 7609r 7613r 7648r 9593rc 18829r 18833r 19776r $ sudo df -h Filesystem Size Used Avail Use% Mounted on /dev/sdb6 496G 366G 106G 78% / udev 2.0G 4.0K 2.0G 1% /dev tmpfs 791M 1.5M 790M 1% /run none 5.0M 0 5.0M 0% /run/lock none 2.0G 672K 2.0G 1% /run/shm /dev/sda1 932G 312G 620G 34% /media/Elements /home/solderblob/.Private 496G 366G 106G 78% /home/solderblob /dev/sdb2 188G 100G 88G 54% /media/A2B24EACB24E852F /dev/sdb1 100M 25M 76M 25% /media/System Reserved $ sudo fdisk -l Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00093cab Device Boot Start End Blocks Id System /dev/sda1 2048 1953519615 976758784 7 HPFS/NTFS/exFAT Disk /dev/sdb: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000e8d9b Device Boot Start End Blocks Id System /dev/sdb1 * 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sdb2 206848 392378768 196085960+ 7 HPFS/NTFS/exFAT /dev/sdb3 392380414 1465147391 536383489 5 Extended /dev/sdb5 1456762880 1465147391 4192256 82 Linux swap / Solaris /dev/sdb6 392380416 1448374271 527996928 83 Linux /dev/sdb7 1448376320 1456758783 4191232 82 Linux swap / Solaris Partition table entries are not in disk order $ cat /etc/fstab # <file system> <mount point> <type> <options> <dump> <pass> UUID=77039a2a-83d4-47a1-8a8c-a2ec4e4dfd0e / ext4 defaults 0 1 UUID=F6549CC4549C88CF /media/Elements ntfs-3g users 0 0 $ sudo blkid /dev/sda1: LABEL="Elements" UUID="F6549CC4549C88CF" TYPE="ntfs" /dev/sdb1: LABEL="System Reserved" UUID="5CDE130FDE12E156" TYPE="ntfs" /dev/sdb2: UUID="A2B24EACB24E852F" TYPE="ntfs" /dev/sdb6: UUID="77039a2a-83d4-47a1-8a8c-a2ec4e4dfd0e" TYPE="ext4" $ sudo blkid -c /dev/null (appears to be exactly the same as above) /dev/sda1: LABEL="Elements" UUID="F6549CC4549C88CF" TYPE="ntfs" /dev/sdb1: LABEL="System Reserved" UUID="5CDE130FDE12E156" TYPE="ntfs" /dev/sdb2: UUID="A2B24EACB24E852F" TYPE="ntfs" /dev/sdb6: UUID="77039a2a-83d4-47a1-8a8c-a2ec4e4dfd0e" TYPE="ext4" $ mount /dev/sdb6 on / type ext4 (rw) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) udev on /dev type devtmpfs (rw,mode=0755) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) /dev/sda1 on /media/Elements type fuseblk (rw,noexec,nosuid,nodev,allow_other,blksize=4096) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) /home/solderblob/.Private on /home/solderblob type ecryptfs (ecryptfs_check_dev_ruid,ecryptfs_cipher=aes,ecryptfs_key_bytes=16,ecryptfs_unlink_sigs,ecryptfs_sig=76a47b0175afa48d,ecryptfs_fnek_sig=391b2d8b155215f7) gvfs-fuse-daemon on /home/solderblob/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=solderblob) /dev/sdb2 on /media/A2B24EACB24E852F type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096) /dev/sdb1 on /media/System Reserved type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096) $ ls -a . A2B24EACB24E852F Ubuntu 12.04.1 LTS amd64 .. Elements System Reserved $ cat /proc/mounts rootfs / rootfs rw 0 0 sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0 proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0 udev /dev devtmpfs rw,relatime,size=2013000k,nr_inodes=503250,mode=755 0 0 devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0 tmpfs /run tmpfs rw,nosuid,relatime,size=809872k,mode=755 0 0 /dev/disk/by-uuid/77039a2a-83d4-47a1-8a8c-a2ec4e4dfd0e / ext4 rw,relatime,user_xattr,acl,barrier=1,data=ordered 0 0 none /sys/fs/fuse/connections fusectl rw,relatime 0 0 none /sys/kernel/debug debugfs rw,relatime 0 0 none /sys/kernel/security securityfs rw,relatime 0 0 none /run/lock tmpfs rw,nosuid,nodev,noexec,relatime,size=5120k 0 0 none /run/shm tmpfs rw,nosuid,nodev,relatime 0 0 /dev/sda1 /media/Elements fuseblk rw,nosuid,nodev,noexec,relatime,user_id=0,group_id=0,allow_other,blksize=4096 0 0 binfmt_misc /proc/sys/fs/binfmt_misc binfmt_misc rw,nosuid,nodev,noexec,relatime 0 0 /home/solderblob/.Private /home/solderblob ecryptfs rw,relatime,ecryptfs_fnek_sig=391b2d8b155215f7,ecryptfs_sig=76a47b0175afa48d,ecryptfs_cipher=aes,ecryptfs_key_bytes=16,ecryptfs_unlink_sigs 0 0 gvfs-fuse-daemon /home/solderblob/.gvfs fuse.gvfs-fuse-daemon rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0 /dev/sdb2 /media/A2B24EACB24E852F fuseblk rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096 0 0 /dev/sdb1 /media/System\040Reserved fuseblk rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096 0 0 gvfs-fuse-daemon /root/.gvfs fuse.gvfs-fuse-daemon rw,nosuid,nodev,relatime,user_id=0,group_id=0 0 0 $ fsck fsck from util-linux 2.20.1 e2fsck 1.42 (29-Nov-2011) /dev/sdb6 is mounted. WARNING!!! The filesystem is mounted. If you continue you ***WILL*** cause ***SEVERE*** filesystem damage. Do you really want to continue<n>? no check aborted.

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• How to use Azure storage for uploading and displaying pictures.

  - by Magnus Karlsson

  Basic set up of Azure storage for local development and production. This is a somewhat completion of the following guide from http://www.windowsazure.com/en-us/develop/net/how-to-guides/blob-storage/ that also involves a practical example that I believe is commonly used, i.e. upload and present an image from a user.   First we set up for local storage and then we configure for them to work on a web role. Steps: 1. Configure connection string locally. 2. Configure model, controllers and razor views.   1. Setup connectionsstring 1.1 Right click your web role and choose “Properties”. 1.2 Click Settings. 1.3 Add setting. 1.4 Name your setting. This will be the name of the connectionstring. 1.5 Click the ellipsis to the right. (the ellipsis appear when you mark the area. 1.6 The following window appears- Select “Windows Azure storage emulator” and click ok.   Now we have a connection string to use. To be able to use it we need to make sure we have windows azure tools for storage. 2.1 Click Tools –> Library Package manager –> Manage Nuget packages for solution. 2.2 This is what it looks like after it has been added.   Now on to what the code should look like. 3.1 First we need a view which collects images to upload. Here Index.cshtml. 1: @model List<string> 2:  3: @{ 4: ViewBag.Title = "Index"; 5: } 6:  7: <h2>Index</h2> 8: <form action="@Url.Action("Upload")" method="post" enctype="multipart/form-data"> 9:  10: <label for="file">Filename:</label> 11: <input type="file" name="file" id="file1" /> 12: <br /> 13: <label for="file">Filename:</label> 14: <input type="file" name="file" id="file2" /> 15: <br /> 16: <label for="file">Filename:</label> 17: <input type="file" name="file" id="file3" /> 18: <br /> 19: <label for="file">Filename:</label> 20: <input type="file" name="file" id="file4" /> 21: <br /> 22: <input type="submit" value="Submit" /> 23: 24: </form> 25:  26: @foreach (var item in Model) { 27:  28: <img src="@item" alt="Alternate text"/> 29: } 3.2 We need a controller to receive the post. Notice the “containername” string I send to the blobhandler. I use this as a folder for the pictures for each user. If this is not a requirement you could just call it container or anything with small characters directly when creating the container. 1: public ActionResult Upload(IEnumerable<HttpPostedFileBase> file) 2: { 3: BlobHandler bh = new BlobHandler("containername"); 4: bh.Upload(file); 5: var blobUris=bh.GetBlobs(); 6: 7: return RedirectToAction("Index",blobUris); 8: } 3.3 The handler model. I’ll let the comments speak for themselves. 1: public class BlobHandler 2: { 3: // Retrieve storage account from connection string. 4: CloudStorageAccount storageAccount = CloudStorageAccount.Parse( 5: CloudConfigurationManager.GetSetting("StorageConnectionString")); 6: 7: private string imageDirecoryUrl; 8: 9: /// <summary> 10: /// Receives the users Id for where the pictures are and creates 11: /// a blob storage with that name if it does not exist. 12: /// </summary> 13: /// <param name="imageDirecoryUrl"></param> 14: public BlobHandler(string imageDirecoryUrl) 15: { 16: this.imageDirecoryUrl = imageDirecoryUrl; 17: // Create the blob client. 18: CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient(); 19: 20: // Retrieve a reference to a container. 21: CloudBlobContainer container = blobClient.GetContainerReference(imageDirecoryUrl); 22: 23: // Create the container if it doesn't already exist. 24: container.CreateIfNotExists(); 25: 26: //Make available to everyone 27: container.SetPermissions( 28: new BlobContainerPermissions 29: { 30: PublicAccess = BlobContainerPublicAccessType.Blob 31: }); 32: } 33: 34: public void Upload(IEnumerable<HttpPostedFileBase> file) 35: { 36: // Create the blob client. 37: CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient(); 38: 39: // Retrieve a reference to a container. 40: CloudBlobContainer container = blobClient.GetContainerReference(imageDirecoryUrl); 41: 42: if (file != null) 43: { 44: foreach (var f in file) 45: { 46: if (f != null) 47: { 48: CloudBlockBlob blockBlob = container.GetBlockBlobReference(f.FileName); 49: blockBlob.UploadFromStream(f.InputStream); 50: } 51: } 52: } 53: } 54: 55: public List<string> GetBlobs() 56: { 57: // Create the blob client. 58: CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient(); 59: 60: // Retrieve reference to a previously created container. 61: CloudBlobContainer container = blobClient.GetContainerReference(imageDirecoryUrl); 62: 63: List<string> blobs = new List<string>(); 64: 65: // Loop over blobs within the container and output the URI to each of them 66: foreach (var blobItem in container.ListBlobs()) 67: blobs.Add(blobItem.Uri.ToString()); 68: 69: return blobs; 70: } 71: } 3.4 So, when the files have been uploaded we will get them to present them to out user in the index page. Pretty straight forward. In this example we only present the image by sending the Uri’s to the view. A better way would be to save them up in a view model containing URI, metadata, alternate text, and other relevant information but for this example this is all we need.   4. Now press F5 in your solution to try it out. You can see the storage emulator UI here:     4.1 If you get any exceptions or errors I suggest to first check if the service Is running correctly. I had problem with this and they seemed related to the installation and a reboot fixed my problems.     5. Set up for Cloud storage. To do this we need to add configuration for cloud just as we did for local in step one. 5.1 We need our keys to do this. Go to the windows Azure menagement portal, select storage icon to the right and click “Manage keys”. (Image from a different blog post though).   5.2 Do as in step 1.but replace step 1.6 with: 1.6 Choose “Manually entered credentials”. Enter your account name. 1.7 Paste your Account Key from step 5.1. and click ok.   5.3. Save, publish and run! Please feel free to ask any questions using the comments form at the bottom of this page. I will get back to you to help you solve any questions. Our consultancy agency also provides services in the Nordic regions if you would like any further support.

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• ASP.NET MVC 3 Hosting :: MVC 2 Strongly Typed HTML Helper and Enhanced Validation Sample

  - by mbridge

  In lue of the off the official release of ASP.NET MVC 2 RTM, I decided I would put together a quick sample of the enhanced HTML.Helpers and validation controls. I am going to use my sample event site where I will have a form so a user can search for information about a certain events. So when the Search page loads the Search action is fired return my strongly typed model. to the view.    1: [HttpGet]    2: public ViewResult Search(): public ViewResult Search()    3: {    4:     IList<EventsModel> result = _eventsService.GetEventList();    5:     var viewModel = new EventSearchModel    6:                         {    7:                             EventList = new SelectList(result, "EventCode","EventName","Select Event")    8:                         };    9:     return View(viewModel);  10: } Nothing special here, although I did want to show how to load up a strongly typed drop down list because that hung me up for a little bit. So to that, I am going to pass back a SelectList to the view and my HTML helper should no how to load this. So lets take a look at the mark up for the view.    1: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master"    2: Inherits="System.Web.Mvc.ViewPage<EventsSample.Models.EventSearchModel>" %>    3:     4: <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">    5:     Search    6: </asp:Content>    7:     8: <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">    9:   10:     <h2>Search for Events</h2>  11:   12:     <% using (Html.BeginForm("Search","Events")) {%>  13:         <%= Html.ValidationSummary(true) %>  14:          15:         <fieldset>  16:             <legend>Fields</legend>  17:              18:             <div class="editor-label">  19:                 <%= Html.LabelFor(model => model.EventNumber) %>  20:             </div>  21:             <div class="editor-field">  22:                 <%= Html.TextBoxFor(model => model.EventNumber) %>  23:                 <%= Html.ValidationMessageFor(model => model.EventNumber) %>  24:             </div>  25:              26:             <div class="editor-label">  27:                 <%= Html.LabelFor(model => model.GuestLastName) %>  28:             </div>  29:             <div class="editor-field">  30:                 <%= Html.TextBoxFor(model => model.GuestLastName) %>  31:                 <%= Html.ValidationMessageFor(model => model.GuestLastName) %>  32:             </div>  33:              34:             <div class="editor-label">  35:                 <%= Html.LabelFor(model => model.EventName) %>  36:             </div>  37:             <div class="editor-field">  38:                 <%= Html.DropDownListFor(model => model.EventName, Model.EventList,"Select Event") %>  39:                 <%= Html.ValidationMessageFor(model => model.EventName) %>  40:             </div>  41:              42:             <p>  43:                 <input type="submit" value="Save" />  44:             </p>  45:         </fieldset>  46:   47:     <% } %>  48:   49:     <div>  50:         <%= Html.ActionLink("Back to List", "Index") %>  51:     </div>  52:   53: </asp:Content> A nice feature is the scaffolding that MVC has to generate code. I simply right clicked inside my Search() action, inside the EventsController and selected “Add View” and then I selected my strongly typed object that I wanted to pass to the view and also selected that I wanted the content type be “Edit”. With that the aspx page was completely generated, although I did have to go back in and change the textbox for the Event Names to a drop down list of the names to select from. The new feature with MVC 2 are the strongly typed HTML helpers. So now, my textboxes, drop down list, and validation helpers are all strongly typed to my model.  This features gives you the benefits of intellisense and also makes it easier to debug. “The Gu” has a great post about the feature in case you want more details. The DropDownListFor function to generate the drop down list was a little tricky for me. You first need to use a Lanbda expression to pass in the property you want the selected value assigned to in your model, and then you need to pass in the list directly from the model. Validations To validate the form, you can use the strongly type validation HTML helpers which will inspect your model and return errors if the validation fails. The definitions of these rules are set directly on the Model itself so lets take a look.    1: using System.ComponentModel.DataAnnotations;    2: using System.Web.Mvc;    3:     4: namespace EventsSample.Models    5: {    6:     public class EventSearchModel    7:     {    8:         [Required(ErrorMessage = "Please enter the event number.")]    9:         [RegularExpression(@"\w{6}",  10:             ErrorMessage = "The Event Number must be 6 letters and/or numbers.")]  11:         public string EventNumber { get; set; }  12:   13:         [Required(ErrorMessage = "Please enter the guest's last name.")]  14:         [RegularExpression(@"^[A-Za-zÀ-ÖØ-öø-ÿ1-9 '\-\.]{1,22}$",  15:             ErrorMessage = "The gueest's last name must 1 to 20 characters.")]  16:         public string GuestLastName { get; set; }  17:   18:         public string EventName { get; set; }  19:         public SelectList EventList { get; set; }  20:     }  21: } Pretty cool! Okay, the only thing left to do is perform the validation in the POST action.    1: [HttpPost]    2: public ViewResult Search(EventSearchModel eventSearchModel)    3: {    4:     if (ModelState.IsValid) return View("SearchResults");    5:     else    6:     {    7:          IList<EventsModel> result = _eventsService.GetEventList();    8:         eventSearchModel.EventList = new SelectList(result, "EVentCode","EventName");   9:   10:         return View(eventSearchModel);  11:     }  12: }  13:     } If the form entries are valid, here I am simply displaying the SearchResult, but in a real world sample I would also go out get the results first. You get the idea though. In my case, when the form is not valid, I also had to reload my SelectList with the event names before I loaded the page again. Remember this is MVC, no _VieState here :) So that’s it. Now my form is validating the data and when it fails it looks like this.

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• MVC Portable Area Modules *Without* MasterPages

  - by Steve Michelotti

  Portable Areas from MvcContrib provide a great way to build modular and composite applications on top of MVC. In short, portable areas provide a way to distribute MVC binary components as simple .NET assemblies where the aspx/ascx files are actually compiled into the assembly as embedded resources. I’ve blogged about Portable Areas in the past including this post here which talks about embedding resources and you can read more of an intro to Portable Areas here. As great as Portable Areas are, the question that seems to come up the most is: what about MasterPages? MasterPages seems to be the one thing that doesn’t work elegantly with portable areas because you specify the MasterPage in the @Page directive and it won’t use the same mechanism of the view engine so you can’t just embed them as resources. This means that you end up referencing a MasterPage that exists in the host application but not in your portable area. If you name the ContentPlaceHolderId’s correctly, it will work – but it all seems a little fragile. Ultimately, what I want is to be able to build a portable area as a module which has no knowledge of the host application. I want to be able to invoke the module by a full route on the user’s browser and it gets invoked and “automatically appears” inside the application’s visual chrome just like a MasterPage. So how could we accomplish this with portable areas? With this question in mind, I looked around at what other people are doing to address similar problems. Specifically, I immediately looked at how the Orchard team is handling this and I found it very compelling. Basically Orchard has its own custom layout/theme framework (utilizing a custom view engine) that allows you to build your module without any regard to the host. You simply decorate your controller with the [Themed] attribute and it will render with the outer chrome around it: 1: [Themed] 2: public class HomeController : Controller Here is the slide from the Orchard talk at this year MIX conference which shows how it conceptually works:   It’s pretty cool stuff.  So I figure, it must not be too difficult to incorporate this into the portable areas view engine as an optional piece of functionality. In fact, I’ll even simplify it a little – rather than have 1) Document.aspx, 2) Layout.ascx, and 3) <view>.ascx (as shown in the picture above); I’ll just have the outer page be “Chrome.aspx” and then the specific view in question. The Chrome.aspx not only takes the place of the MasterPage, but now since we’re no longer constrained by the MasterPage infrastructure, we have the choice of the Chrome.aspx living in the host or inside the portable areas as another embedded resource! Disclaimer: credit where credit is due – much of the code from this post is me re-purposing the Orchard code to suit my needs. To avoid confusion with Orchard, I’m going to refer to my implementation (which will be based on theirs) as a Chrome rather than a Theme. The first step I’ll take is to create a ChromedAttribute which adds a flag to the current HttpContext to indicate that the controller designated Chromed like this: 1: [Chromed] 2: public class HomeController : Controller The attribute itself is an MVC ActionFilter attribute: 1: public class ChromedAttribute : ActionFilterAttribute 2: { 3: public override void OnActionExecuting(ActionExecutingContext filterContext) 4: { 5: var chromedAttribute = GetChromedAttribute(filterContext.ActionDescriptor); 6: if (chromedAttribute != null) 7: { 8: filterContext.HttpContext.Items[typeof(ChromedAttribute)] = null; 9: } 10: } 11:   12: public static bool IsApplied(RequestContext context) 13: { 14: return context.HttpContext.Items.Contains(typeof(ChromedAttribute)); 15: } 16:   17: private static ChromedAttribute GetChromedAttribute(ActionDescriptor descriptor) 18: { 19: return descriptor.GetCustomAttributes(typeof(ChromedAttribute), true) 20: .Concat(descriptor.ControllerDescriptor.GetCustomAttributes(typeof(ChromedAttribute), true)) 21: .OfType<ChromedAttribute>() 22: .FirstOrDefault(); 23: } 24: } With that in place, we only have to override the FindView() method of the custom view engine with these 6 lines of code: 1: public override ViewEngineResult FindView(ControllerContext controllerContext, string viewName, string masterName, bool useCache) 2: { 3: if (ChromedAttribute.IsApplied(controllerContext.RequestContext)) 4: { 5: var bodyView = ViewEngines.Engines.FindPartialView(controllerContext, viewName); 6: var documentView = ViewEngines.Engines.FindPartialView(controllerContext, "Chrome"); 7: var chromeView = new ChromeView(bodyView, documentView); 8: return new ViewEngineResult(chromeView, this); 9: } 10:   11: // Just execute normally without applying Chromed View Engine 12: return base.FindView(controllerContext, viewName, masterName, useCache); 13: } If the view engine finds the [Chromed] attribute, it will invoke it’s own process – otherwise, it’ll just defer to the normal web forms view engine (with masterpages). The ChromeView’s primary job is to independently set the BodyContent on the view context so that it can be rendered at the appropriate place: 1: public class ChromeView : IView 2: { 3: private ViewEngineResult bodyView; 4: private ViewEngineResult documentView; 5:   6: public ChromeView(ViewEngineResult bodyView, ViewEngineResult documentView) 7: { 8: this.bodyView = bodyView; 9: this.documentView = documentView; 10: } 11:   12: public void Render(ViewContext viewContext, System.IO.TextWriter writer) 13: { 14: ChromeViewContext chromeViewContext = ChromeViewContext.From(viewContext); 15:   16: // First render the Body view to the BodyContent 17: using (var bodyViewWriter = new StringWriter()) 18: { 19: var bodyViewContext = new ViewContext(viewContext, bodyView.View, viewContext.ViewData, viewContext.TempData, bodyViewWriter); 20: this.bodyView.View.Render(bodyViewContext, bodyViewWriter); 21: chromeViewContext.BodyContent = bodyViewWriter.ToString(); 22: } 23: // Now render the Document view 24: this.documentView.View.Render(viewContext, writer); 25: } 26: } The ChromeViewContext (code excluded here) mainly just has a string property for the “BodyContent” – but it also makes sure to put itself in the HttpContext so it’s available. Finally, we created a little extension method so the module’s view can be rendered in the appropriate place: 1: public static void RenderBody(this HtmlHelper htmlHelper) 2: { 3: ChromeViewContext chromeViewContext = ChromeViewContext.From(htmlHelper.ViewContext); 4: htmlHelper.ViewContext.Writer.Write(chromeViewContext.BodyContent); 5: } At this point, the other thing left is to decide how we want to implement the Chrome.aspx page. One approach is the copy/paste the HTML from the typical Site.Master and change the main content placeholder to use the HTML helper above – this way, there are no MasterPages anywhere. Alternatively, we could even have Chrome.aspx utilize the MasterPage if we wanted (e.g., in the case where some pages are Chromed and some pages want to use traditional MasterPage): 1: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %> 2: <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> 3: <% Html.RenderBody(); %> 4: </asp:Content> At this point, it’s all academic. I can create a controller like this: 1: [Chromed] 2: public class WidgetController : Controller 3: { 4: public ActionResult Index() 5: { 6: return View(); 7: } 8: } Then I’ll just create Index.ascx (a partial view) and put in the text “Inside my widget”. Now when I run the app, I can request the full route (notice the controller name of “widget” in the address bar below) and the HTML from my Index.ascx will just appear where it is supposed to.   This means no more warnings for missing MasterPages and no more need for your module to have knowledge of the host’s MasterPage placeholders. You have the option of using the Chrome.aspx in the host or providing your own while embedding it as an embedded resource itself. I’m curious to know what people think of this approach. The code above was done with my own local copy of MvcContrib so it’s not currently something you can download. At this point, these are just my initial thoughts – just incorporating some ideas for Orchard into non-Orchard apps to enable building modular/composite apps more easily. Additionally, on the flip side, I still believe that Portable Areas have potential as the module packaging story for Orchard itself.   What do you think?

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• Tracing Silex from PHP to the OS with DTrace

  - by cj

  In this blog post I show the full stack tracing of Brendan Gregg's php_syscolors.d script in the DTrace Toolkit. The Toolkit contains a dozen very useful PHP DTrace scripts and many more scripts for other languages and the OS. For this example, I'll trace the PHP micro framework Silex, which was the topic of the second of two talks by Dustin Whittle at a recent SF PHP Meetup. His slides are at Silex: From Micro to Full Stack. Installing DTrace and PHP The php_syscolors.d script uses some static PHP probes and some kernel probes. For Oracle Linux I discussed installing DTrace and PHP in DTrace PHP Using Oracle Linux 'playground' Pre-Built Packages. On other platforms with DTrace support, follow your standard procedures to enable DTrace and load the correct providers. The sdt and systrace providers are required in addition to fasttrap. On Oracle Linux, I loaded the DTrace modules like: # modprobe fasttrap # modprobe sdt # modprobe systrace # chmod 666 /dev/dtrace/helper Installing the DTrace Toolkit I download DTraceToolkit-0.99.tar.gz and extracted it: $ tar -zxf DTraceToolkit-0.99.tar.gz The PHP scripts are in the Php directory and examples in the Examples directory. Installing Silex I downloaded the "fat" Silex .tgz file from the download page and extracted it: $ tar -zxf silex_fat.tgz I changed the demonstration silex/web/index.php so I could use the PHP development web server: <?php // web/index.php $filename = __DIR__.preg_replace('#(\?.*)$#', '', $_SERVER['REQUEST_URI']); if (php_sapi_name() === 'cli-server' && is_file($filename)) { return false; } require_once __DIR__.'/../vendor/autoload.php'; $app = new Silex\Application(); //$app['debug'] = true; $app->get('/hello', function() { return 'Hello!'; }); $app->run(); ?> Running DTrace The php_syscolors.d script uses the -Z option to dtrace, so it can be started before PHP, i.e. when there are zero of the requested probes available to be traced. I ran DTrace like: # cd DTraceToolkit-0.99/Php # ./php_syscolors.d Next, I started the PHP developer web server in a second terminal: $ cd silex $ php -S localhost:8080 -t web web/index.php At this point, the web server is idle, waiting for requests. DTrace is idle, waiting for the probes in php_syscolors.d to be fired, at which time the action associated with each probe will run. I then loaded the demonstration page in a browser: http://localhost:8080/hello When the request was fulfilled and the simple output of "Hello" was displayed, I ^C'd php and dtrace in their terminals to stop them. DTrace output over a thousand lines long had been generated. Here is one snippet from when run() was invoked: C PID/TID DELTA(us) FILE:LINE TYPE -- NAME ... 1 4765/4765 21 Application.php:487 func -> run 1 4765/4765 29 ClassLoader.php:182 func -> loadClass 1 4765/4765 17 ClassLoader.php:198 func -> findFile 1 4765/4765 31 ":- syscall -> access 1 4765/4765 26 ":- syscall <- access 1 4765/4765 16 ClassLoader.php:198 func <- findFile 1 4765/4765 25 ":- syscall -> newlstat 1 4765/4765 15 ":- syscall <- newlstat 1 4765/4765 13 ":- syscall -> newlstat 1 4765/4765 13 ":- syscall <- newlstat 1 4765/4765 22 ":- syscall -> newlstat 1 4765/4765 14 ":- syscall <- newlstat 1 4765/4765 15 ":- syscall -> newlstat 1 4765/4765 60 ":- syscall <- newlstat 1 4765/4765 13 ":- syscall -> newlstat 1 4765/4765 13 ":- syscall <- newlstat 1 4765/4765 20 ":- syscall -> open 1 4765/4765 16 ":- syscall <- open 1 4765/4765 26 ":- syscall -> newfstat 1 4765/4765 12 ":- syscall <- newfstat 1 4765/4765 17 ":- syscall -> newfstat 1 4765/4765 12 ":- syscall <- newfstat 1 4765/4765 12 ":- syscall -> newfstat 1 4765/4765 12 ":- syscall <- newfstat 1 4765/4765 20 ":- syscall -> mmap 1 4765/4765 14 ":- syscall <- mmap 1 4765/4765 3201 ":- syscall -> mmap 1 4765/4765 27 ":- syscall <- mmap 1 4765/4765 1233 ":- syscall -> munmap 1 4765/4765 53 ":- syscall <- munmap 1 4765/4765 15 ":- syscall -> close 1 4765/4765 13 ":- syscall <- close 1 4765/4765 34 Request.php:32 func -> main 1 4765/4765 22 Request.php:32 func <- main 1 4765/4765 31 ClassLoader.php:182 func <- loadClass 1 4765/4765 33 Request.php:249 func -> createFromGlobals 1 4765/4765 29 Request.php:198 func -> __construct 1 4765/4765 24 Request.php:218 func -> initialize 1 4765/4765 26 ClassLoader.php:182 func -> loadClass 1 4765/4765 89 ClassLoader.php:198 func -> findFile 1 4765/4765 43 ":- syscall -> access ... The output shows PHP functions being called and returning (and where they are located) and which system calls the PHP functions in turn invoked. The time each line took from the previous one is displayed in the third column. The first column is the CPU number. In this example, the process was always on CPU 1 so the output is naturally ordered without requiring post-processing, or the D script requiring to be modified to display a time stamp. On a terminal, the output of php_syscolors.d is color-coded according to whether each function is a PHP or system one, hence the file name. Summary With one tool, I was able to trace the interaction of a user application with the operating system. I was able to do this to an application running "live" in a web context. The DTrace Toolkit provides a very handy repository of DTrace information. Even though the PHP scripts were created in the time frame of the original PHP DTrace PECL extension, which only had PHP function entry and return probes, the scripts provide core examples for custom investigation and resolution scripts. You can easily adapt the ideas and and create scripts using the other PHP static probes, which are listed in the PHP Manual. Because DTrace is "always on", you can take advantage of it to resolve development questions or fix production situations.

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• Creating a Training Lab on Windows Azure

  - by Michael Stephenson

  Originally posted on: http://geekswithblogs.net/michaelstephenson/archive/2013/06/17/153149.aspxThis week we are preparing for a training course that Alan Smith will be running for the support teams at one of my customers around Windows Azure. In order to facilitate the training lab we have a few prerequisites we need to handle. One of the biggest ones is that although the support team all have MSDN accounts the local desktops they work on are not ideal for running most of the labs as we want to give them some additional developer background training around Azure. Some recent Azure announcements really help us in this area: MSDN software can now be used on Azure VM You don't pay for Azure VM's when they are no longer used  Since the support team only have limited experience of Windows Azure and the organisation also have an Enterprise Agreement we decided it would be best value for money to spin up a training lab in a subscription on the EA and then we can turn the machines off when we are done. At the same time we would be able to spin them back up when the users need to do some additional lab work once the training course is completed. In order to achieve this I wanted to create a powershell script which would setup my training lab. The aim was to create 18 VM's which would be based on a prebuilt template with Visual Studio and the Azure development tools. The script I used is described below The Start & Variables The below text will setup the powershell environment and some variables which I will use elsewhere in the script. It will also import the Azure Powershell cmdlets. You can see below that I will need to download my publisher settings file and know some details from my Azure account. At this point I will assume you have a basic understanding of Azure & Powershell so already know how to do this. Set-ExecutionPolicy Unrestrictedcls $startTime = get-dateImport-Module "C:\Program Files (x86)\Microsoft SDKs\Windows Azure\PowerShell\Azure\Azure.psd1"# Azure Publisher Settings $azurePublisherSettings = '<Your settings file>.publishsettings'  # Subscription Details $subscriptionName = "<Your subscription name>" $defaultStorageAccount = "<Your default storage account>"  # Affinity Group Details $affinityGroup = '<Your affinity group>' $dataCenter = 'West Europe' # From Get-AzureLocation  # VM Details $baseVMName = 'TRN' $adminUserName = '<Your admin username>' $password = '<Your admin password>' $size = 'Medium' $vmTemplate = '<The name of your VM template image>' $rdpFilePath = '<File path to save RDP files to>' $machineSettingsPath = '<File path to save machine info to>'    Functions In the next section of the script I have some functions which are used to perform certain actions. The first is called CreateVM. This will do the following actions: If the VM already exists it will be deleted Create the cloud service Create the VM from the template I have created Add an endpoint so we can RDP to them all over the same port Download the RDP file so there is a short cut the trainees can easily access the machine via Write settings for the machine to a log file  function CreateVM($machineNo) { # Specify a name for the new VM $machineName = "$baseVMName-$machineNo" Write-Host "Creating VM: $machineName"       # Get the Azure VM Image      $myImage = Get-AzureVMImage $vmTemplate   #If the VM already exists delete and re-create it $existingVm = Get-AzureVM -Name $machineName -ServiceName $serviceName if($existingVm -ne $null) { Write-Host "VM already exists so deleting it" Remove-AzureVM -Name $machineName -ServiceName $serviceName }   "Creating Service" $serviceName = "bupa-azure-train-$machineName" Remove-AzureService -Force -ServiceName $serviceName New-AzureService -Location $dataCenter -ServiceName $serviceName   Write-Host "Creating VM: $machineName" New-AzureQuickVM -Windows -name $machineName -ServiceName $serviceName -ImageName $myImage.ImageName -InstanceSize $size -AdminUsername $adminUserName -Password $password  Write-Host "Updating the RDP endpoint for $machineName" Get-AzureVM -name $machineName -ServiceName $serviceName ` | Add-AzureEndpoint -Name RDP -Protocol TCP -LocalPort 3389 -PublicPort 550 ` | Update-AzureVM    Write-Host "Get the RDP File for machine $machineName" $machineRDPFilePath = "$rdpFilePath\$machineName.rdp" Get-AzureRemoteDesktopFile -name $machineName -ServiceName $serviceName -LocalPath "$machineRDPFilePath"   WriteMachineSettings "$machineName" "$serviceName" }    The delete machine settings function is used to delete the log file before we start re-running the process.  function DeleteMachineSettings() { Write-Host "Deleting the machine settings output file" [System.IO.File]::Delete("$machineSettingsPath"); }    The write machine settings function will get the VM and then record its details to the log file. The importance of the log file is that I can easily provide the information for all of the VM's to our infrastructure team to be able to configure access to all of the VM's    function WriteMachineSettings([string]$vmName, [string]$vmServiceName) { Write-Host "Writing to the machine settings output file"   $vm = Get-AzureVM -name $vmName -ServiceName $vmServiceName $vmEndpoint = Get-AzureEndpoint -VM $vm -Name RDP   $sb = new-object System.Text.StringBuilder $sb.Append("Service Name: "); $sb.Append($vm.ServiceName); $sb.Append(", "); $sb.Append("VM: "); $sb.Append($vm.Name); $sb.Append(", "); $sb.Append("RDP Public Port: "); $sb.Append($vmEndpoint.Port); $sb.Append(", "); $sb.Append("Public DNS: "); $sb.Append($vmEndpoint.Vip); $sb.AppendLine(""); [System.IO.File]::AppendAllText($machineSettingsPath, $sb.ToString());  } # end functions    Rest of Script In the rest of the script it is really just the bit that orchestrates the actions we want to happen. It will load the publisher settings, select the Azure subscription and then loop around the CreateVM function and create 16 VM's  Import-AzurePublishSettingsFile $azurePublisherSettings Set-AzureSubscription -SubscriptionName $subscriptionName -CurrentStorageAccount $defaultStorageAccount Select-AzureSubscription -SubscriptionName $subscriptionName  DeleteMachineSettings    "Starting creating Bupa International Azure Training Lab" $numberOfVMs = 16  for ($index=1; $index -le $numberOfVMs; $index++) { $vmNo = "$index" CreateVM($vmNo); }    "Finished creating Bupa International Azure Training Lab" # Give it a Minute Start-Sleep -s 60  $endTime = get-date "Script run time " + ($endTime - $startTime)    Conclusion As you can see there is nothing too fancy about this script but in our case of creating a small isolated training lab which is not connected to our corporate network then we can easily use this to provision the lab. Im sure if this is of use to anyone you can easily modify it to do other things with the lab environment too. A couple of points to note are that there are some soft limits in Azure about the number of cores and services your subscription can use. You may need to contact the Azure support team to be able to increase this limit. In terms of the real business value of this approach, it was not possible to use the existing desktops to do the training on, and getting some internal virtual machines would have been relatively expensive and time consuming for our ops team to do. With the Azure option we are able to spin these machines up for a temporary period during the training course and then throw them away when we are done. We expect the costing of this test lab to be very small, especially considering we have EA pricing. As a ball park I think my 18 lab VM training environment will cost in the region of $80 per day on our EA. This is a fraction of the cost of the creation of a single VM on premise.

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• C#/.NET Little Wonders: Comparer&lt;T&gt;.Default

  - by James Michael Hare

  I’ve been working with a wonderful team on a major release where I work, which has had the side-effect of occupying most of my spare time preparing, testing, and monitoring.  However, I do have this Little Wonder tidbit to offer today. Introduction The IComparable<T> interface is great for implementing a natural order for a data type.  It’s a very simple interface with a single method: 1: public interface IComparer<in T> 2: { 3: // Compare two instances of same type. 4: int Compare(T x, T y); 5: }  So what do we expect for the integer return value?  It’s a pseudo-relative measure of the ordering of x and y, which returns an integer value in much the same way C++ returns an integer result from the strcmp() c-style string comparison function: If x == y, returns 0. If x > y, returns > 0 (often +1, but not guaranteed) If x < y, returns < 0 (often –1, but not guaranteed) Notice that the comparison operator used to evaluate against zero should be the same comparison operator you’d use as the comparison operator between x and y.  That is, if you want to see if x > y you’d see if the result > 0. The Problem: Comparing With null Can Be Messy This gets tricky though when you have null arguments.  According to the MSDN, a null value should be considered equal to a null value, and a null value should be less than a non-null value.  So taking this into account we’d expect this instead: If x == y (or both null), return 0. If x > y (or y only is null), return > 0. If x < y (or x only is null), return < 0. But here’s the problem – if x is null, what happens when we attempt to call CompareTo() off of x? 1: // what happens if x is null? 2: x.CompareTo(y); It’s pretty obvious we’ll get a NullReferenceException here.  Now, we could guard against this before calling CompareTo(): 1: int result; 2:  3: // first check to see if lhs is null. 4: if (x == null) 5: { 6: // if lhs null, check rhs to decide on return value. 7: if (y == null) 8: { 9: result = 0; 10: } 11: else 12: { 13: result = -1; 14: } 15: } 16: else 17: { 18: // CompareTo() should handle a null y correctly and return > 0 if so. 19: result = x.CompareTo(y); 20: } Of course, we could shorten this with the ternary operator (?:), but even then it’s ugly repetitive code: 1: int result = (x == null) 2: ? ((y == null) ? 0 : -1) 3: : x.CompareTo(y); Fortunately, the null issues can be cleaned up by drafting in an external Comparer.  The Soltuion: Comparer<T>.Default You can always develop your own instance of IComparer<T> for the job of comparing two items of the same type.  The nice thing about a IComparer is its is independent of the things you are comparing, so this makes it great for comparing in an alternative order to the natural order of items, or when one or both of the items may be null. 1: public class NullableIntComparer : IComparer<int?> 2: { 3: public int Compare(int? x, int? y) 4: { 5: return (x == null) 6: ? ((y == null) ? 0 : -1) 7: : x.Value.CompareTo(y); 8: } 9: }  Now, if you want a custom sort -- especially on large-grained objects with different possible sort fields -- this is the best option you have.  But if you just want to take advantage of the natural ordering of the type, there is an easier way.  If the type you want to compare already implements IComparable<T> or if the type is System.Nullable<T> where T implements IComparable, there is a class in the System.Collections.Generic namespace called Comparer<T> which exposes a property called Default that will create a singleton that represents the default comparer for items of that type.  For example: 1: // compares integers 2: var intComparer = Comparer<int>.Default; 3:  4: // compares DateTime values 5: var dateTimeComparer = Comparer<DateTime>.Default; 6:  7: // compares nullable doubles using the null rules! 8: var nullableDoubleComparer = Comparer<double?>.Default;  This helps you avoid having to remember the messy null logic and makes it to compare objects where you don’t know if one or more of the values is null. This works especially well when creating say an IComparer<T> implementation for a large-grained class that may or may not contain a field.  For example, let’s say you want to create a sorting comparer for a stock open price, but if the market the stock is trading in hasn’t opened yet, the open price will be null.  We could handle this (assuming a reasonable Quote definition) like: 1: public class Quote 2: { 3: // the opening price of the symbol quoted 4: public double? Open { get; set; } 5:  6: // ticker symbol 7: public string Symbol { get; set; } 8:  9: // etc. 10: } 11:  12: public class OpenPriceQuoteComparer : IComparer<Quote> 13: { 14: // Compares two quotes by opening price 15: public int Compare(Quote x, Quote y) 16: { 17: return Comparer<double?>.Default.Compare(x.Open, y.Open); 18: } 19: } Summary Defining a custom comparer is often needed for non-natural ordering or defining alternative orderings, but when you just want to compare two items that are IComparable<T> and account for null behavior, you can use the Comparer<T>.Default comparer generator and you’ll never have to worry about correct null value sorting again.     Technorati Tags: C#,.NET,Little Wonders,BlackRabbitCoder,IComparable,Comparer

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• Turning on collision crashes game

  - by MomentumGaming

  I am getting a null pointer excecption to both my sprite and level. I am working on my mob class, and when I try to move him and the move function is called, the game crashes after checking collision with a null pointer excecption. Taking out the one line that actually checks if the tile located in front of it fixes the problem. Also, if i keep collision ON but don't move the position of the mob (the spider) the game works fine. I will have collision, and the spider appears on the screen, only problem is, getting it to move causes this nasty error that i just can't fix. true Exception in thread "Display" java.lang.NullPointerException at com.apcompsci.game.entity.mob.Mob.collision(Mob.java:67) at com.apcompsci.game.entity.mob.Mob.move(Mob.java:38) at com.apcompsci.game.entity.mob.spider.update(spider.java:58) at com.apcompsci.game.level.Level.update(Level.java:55) at com.apcompsci.game.Game.update(Game.java:128) at com.apcompsci.game.Game.run(Game.java:106) at java.lang.Thread.run(Unknown Source) Here is my renderMob mehtod: public void renderMob(int xp,int yp,Sprite sprite,int flip) { xp -= xOffset; yp-=yOffset; for(int y = 0; y<32; y++) { int ya = y + yp; int ys = y; if(flip == 2||flip == 3)ys = 31-y; for(int x = 0; x<32; x++) { int xa = x + xp; int xs = x; if(flip == 1||flip == 3)xs = 31-x; if(xa < -32 || xa >=width || ya<0||ya>=height) break; if(xa<0) xa =0; int col = sprite.pixels[xs+ys*32]; if(col!= 0x000000) pixels[xa+ya*width] = col; } } } My spider class which determines the sprite and where I control movement, also rendering the spider onto the screen, when I increment ya to move the sprite, I get the crash, but without ya++, it runs flawlessly with a spider sprite on screen: package com.apcompsci.game.entity.mob; import com.apcompsci.game.entity.mob.Mob.Direction; import com.apcompsci.game.graphics.Screen; import com.apcompsci.game.graphics.Sprite; import com.apcompsci.game.level.Level; public class spider extends Mob{ Direction dir; private Sprite sprite; private boolean walking; public spider(int x, int y) { this.x = x <<4; this.y = y <<4; sprite = sprite.spider_forward; } public void update() { int xa = 0, ya = 0; ya++; if(ya<0) { sprite = sprite.spider_forward; dir = Direction.UP; } if(ya>0) { sprite = sprite.spider_back; dir = Direction.DOWN; } if(xa<0) { sprite = sprite.spider_side; dir = Direction.LEFT; } if(xa>0) { sprite = sprite.spider_side; dir = Direction.LEFT; } if(xa!= 0 || ya!= 0) { System.out.println("true"); move(xa,ya); walking = true; } else{ walking = false; } } public void render(Screen screen) { screen.renderMob(x, y, sprite, 0); } } This is th mob class that contains the move() method that is called in the spider class above. This move method calls the collision method. tile and sprite comes up null in the debugger: package com.apcompsci.game.entity.mob; import java.util.ArrayList; import java.util.List; import com.apcompsci.game.entity.Entity; import com.apcompsci.game.entity.projectile.DemiGodProjectile; import com.apcompsci.game.entity.projectile.Projectile; import com.apcompsci.game.graphics.Sprite; public class Mob extends Entity{ protected Sprite sprite; protected boolean moving = false; protected enum Direction { UP,DOWN,LEFT,RIGHT } protected Direction dir; public void move(int xa,int ya) { if(xa != 0 && ya != 0) { move(xa,0); move(0,ya); return; } if(xa>0) dir = Direction.RIGHT; if(xa<0) dir = Direction.LEFT; if(ya>0)dir = Direction.DOWN; if(ya<0)dir = Direction.UP; if(!collision(xa,ya)){ x+= xa; y+=ya; } } public void update() { } public void shoot(int x, int y, double dir) { //dir = Math.toDegrees(dir); Projectile p = new DemiGodProjectile(x, y,dir); level.addProjectile(p); } public boolean collision(int xa,int ya) { boolean solid = false; for(int c = 0; c<4; c++) { int xt = ((x+xa) + c % 2 * 14 - 8 )/16; int yt = ((y+ya) + c / 2 * 12 +3 )/16; if(level.getTile(xt, yt).solid()) solid = true; } return solid; } public void render() { } } Finally, here is the method in which i call the add() method for the spider to add it to the level: protected void loadLevel(String path) { try{ BufferedImage image = ImageIO.read(SpawnLevel.class.getResource(path)); int w = width =image.getWidth(); int h = height = image.getHeight(); tiles = new int[w*h]; image.getRGB(0, 0, w,h, tiles,0, w); } catch(IOException e){ e.printStackTrace(); System.out.println("Exception! Could not load level file!"); } add(new spider(20,45)); } I don't think i need to include the level class but just in case, I have provided a gistHub link for better context. It contains all of the full classes listed above , plus my entity class and maybe another. Thanks for the help if you decide to do so, much appreciated! Also, please tell me if i'm in the wrong section of stackeoverflow, i figured that since this is the gamign section that it belonged but debugging code normally goes into the general section.

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• &lt;%: %&gt;, HtmlEncode, IHtmlString and MvcHtmlString

  - by Shaun

  One of my colleague and friend, Robin is playing and struggling with the ASP.NET MVC 2 on a project these days while I’m struggling with a annoying client. Since it’s his first time to use ASP.NET MVC he was meetings with a lot of problem and I was very happy to share my experience to him. Yesterday he asked me when he attempted to insert a <br /> element into his page he found that the page was rendered like this which is bad. He found his <br /> was shown as a part of the string rather than creating a new line. After checked a bit in his code I found that it’s because he utilized a new ASP.NET markup supported in .NET 4.0 – “<%: %>”. If you have been using ASP.NET MVC 1 or in .NET 3.5 world it would be very common that using <%= %> to show something on the page from the backend code. But when you do it you must ensure that the string that are going to be displayed should be Html-safe, which means all the Html markups must be encoded. Otherwise this might cause an XSS (cross-site scripting) problem. So that you’d better use the code like this below to display anything on the page. In .NET 4.0 Microsoft introduced a new markup to solve this problem which is <%: %>. It will encode the content automatically so that you will no need to check and verify your code manually for the XSS issue mentioned below. But this also means that it will encode all things, include the Html element you want to be rendered. So I changed his code like this and it worked well. After helped him solved this problem and finished a spreadsheet for my boring project I considered a bit more on the <%: %>. Since it will encode all thing why it renders correctly when we use “<%: Html.TextBox(“name”) %>” to show a text box? As you know the Html.TextBox will render a “<input name="name" id="name" type="text"/>” element on the page. If <%: %> will encode everything it should not display a text box. So I dig into the source code of the MVC and found some comments in the class MvcHtmlString. 1: // In ASP.NET 4, a new syntax <%: %> is being introduced in WebForms pages, where <%: expression %> is equivalent to 2: // <%= HttpUtility.HtmlEncode(expression) %>. The intent of this is to reduce common causes of XSS vulnerabilities 3: // in WebForms pages (WebForms views in the case of MVC). This involves the addition of an interface 4: // System.Web.IHtmlString and a static method overload System.Web.HttpUtility::HtmlEncode(object). The interface 5: // definition is roughly: 6: // public interface IHtmlString { 7: // string ToHtmlString(); 8: // } 9: // And the HtmlEncode(object) logic is roughly: 10: // - If the input argument is an IHtmlString, return argument.ToHtmlString(), 11: // - Otherwise, return HtmlEncode(Convert.ToString(argument)). 12: // 13: // Unfortunately this has the effect that calling <%: Html.SomeHelper() %> in an MVC application running on .NET 4 14: // will end up encoding output that is already HTML-safe. As a result, we're changing out HTML helpers to return 15: // MvcHtmlString where appropriate. <%= Html.SomeHelper() %> will continue to work in both .NET 3.5 and .NET 4, but 16: // changing the return types to MvcHtmlString has the added benefit that <%: Html.SomeHelper() %> will also work 17: // properly in .NET 4 rather than resulting in a double-encoded output. MVC developers in .NET 4 will then be able 18: // to use the <%: %> syntax almost everywhere instead of having to remember where to use <%= %> and where to use 19: // <%: %>. This should help developers craft more secure web applications by default. 20: // 21: // To create an MvcHtmlString, use the static Create() method instead of calling the protected constructor. The comment said the encoding rule of the <%: %> would be: If the type of the content is IHtmlString it will NOT encode since the IHtmlString indicates that it’s Html-safe. Otherwise it will use HtmlEncode to encode the content. If we check the return type of the Html.TextBox method we will find that it’s MvcHtmlString, which was implemented the IHtmlString interface dynamically. That is the reason why the “<input name="name" id="name" type="text"/>” was not encoded by <%: %>. So if we want to tell ASP.NET MVC, or I should say the ASP.NET runtime that the content is Html-safe and no need, or should not be encoded we can convert the content into IHtmlString. So another resolution would be like this. Also we can create an extension method as well for better developing experience. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Mvc; 6:  7: namespace ShaunXu.Blogs.IHtmlStringIssue 8: { 9: public static class Helpers 10: { 11: public static MvcHtmlString IsHtmlSafe(this string content) 12: { 13: return MvcHtmlString.Create(content); 14: } 15: } 16: } Then the view would be like this. And the page rendered correctly.         Summary In this post I explained a bit about the new markup in .NET 4.0 – <%: %> and its usage. I also explained a bit about how to control the page content, whether it should be encoded or not. We can see the ASP.NET MVC gives us more points to control the web pages.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• OData &ndash; The easiest service I can create: now with updates

  - by Jon Dalberg

  The other day I created a simple NastyWord service exposed via OData. It was read-only and used an in-memory backing store for the words. Today I’ll modify it to use a file instead of a list and I’ll accept new nasty words by implementing IUpdatable directly. The first thing to do is enable the service to accept new entries. This is done at configuration time by adding the “WriteAppend” access rule: 1: public class NastyWords : DataService<NastyWordsDataSource> 2: { 3: // This method is called only once to initialize service-wide policies. 4: public static void InitializeService(DataServiceConfiguration config) 5: { 6: config.SetEntitySetAccessRule("*", EntitySetRights.AllRead | EntitySetRights.WriteAppend); 7: config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; 8: } 9: }   Next I placed a file, NastyWords.txt, in the “App_Data” folder and added a few *choice* words to start. This required one simple change to our NastyWordDataSource.cs file: 1: public NastyWordsDataSource() 2: { 3: UpdateFromSource(); 4: } 5:   6: private void UpdateFromSource() 7: { 8: var words = File.ReadAllLines(pathToFile); 9: NastyWords = (from w in words 10: select new NastyWord { Word = w }).AsQueryable(); 11: }   Nothing too shocking here, just reading each line from the NastyWords.txt file and exposing them. Next, I implemented IUpdatable which comes with a boat-load of methods. We don’t need all of them for now since we are only concerned with allowing new values. Here are the methods we must implement, all the others throw a NotImplementedException: 1: public object CreateResource(string containerName, string fullTypeName) 2: { 3: var nastyWord = new NastyWord(); 4: pendingUpdates.Add(nastyWord); 5: return nastyWord; 6: } 7:   8: public object ResolveResource(object resource) 9: { 10: return resource; 11: } 12:   13: public void SaveChanges() 14: { 15: var intersect = (from w in pendingUpdates 16: select w.Word).Intersect(from n in NastyWords 17: select n.Word); 18:   19: if (intersect.Count() > 0) 20: throw new DataServiceException(500, "duplicate entry"); 21:   22: var lines = from w in pendingUpdates 23: select w.Word; 24:   25: File.AppendAllLines(pathToFile, 26: lines, 27: Encoding.UTF8); 28:   29: pendingUpdates.Clear(); 30:   31: UpdateFromSource(); 32: } 33:   34: public void SetValue(object targetResource, string propertyName, object propertyValue) 35: { 36: targetResource.GetType().GetProperty(propertyName).SetValue(targetResource, propertyValue, null); 37: }   I use a simple list to contain the pending updates and only commit them when the “SaveChanges” method is called. Here’s the order these methods are called in our service during an insert: CreateResource – here we just instantiate a new NastyWord and stick a reference to it in our pending updates list. SetValue – this is where the “Word” property of the NastyWord instance is set. SaveChanges – get the list of pending updates, barfing on duplicates, write them to the file and clear our pending list. ResolveResource – the newly created resource will be returned directly here since we aren’t dealing with “handles” to objects but the actual objects themselves. Not too bad, eh? I didn’t find this documented anywhere but a little bit of digging in the OData spec and use of Fiddler made it pretty easy to figure out. Here is some client code which would add a new nasty word: 1: static void Main(string[] args) 2: { 3: var svc = new ServiceReference1.NastyWordsDataSource(new Uri("http://localhost.:60921/NastyWords.svc")); 4: svc.AddToNastyWords(new ServiceReference1.NastyWord() { Word = "shat" }); 5:   6: svc.SaveChanges(); 7: }   Here’s all of the code so far for to implement the service: 1: using System; 2: using System.Collections.Generic; 3: using System.Data.Services; 4: using System.Data.Services.Common; 5: using System.Linq; 6: using System.ServiceModel.Web; 7: using System.Web; 8: using System.IO; 9: using System.Text; 10:   11: namespace ONasty 12: { 13: [DataServiceKey("Word")] 14: public class NastyWord 15: { 16: public string Word { get; set; } 17: } 18:   19: public class NastyWordsDataSource : IUpdatable 20: { 21: private List<NastyWord> pendingUpdates = new List<NastyWord>(); 22: private string pathToFile = @"path to your\App_Data\NastyWords.txt"; 23:   24: public NastyWordsDataSource() 25: { 26: UpdateFromSource(); 27: } 28:   29: private void UpdateFromSource() 30: { 31: var words = File.ReadAllLines(pathToFile); 32: NastyWords = (from w in words 33: select new NastyWord { Word = w }).AsQueryable(); 34: } 35:   36: public IQueryable<NastyWord> NastyWords { get; private set; } 37:   38: public void AddReferenceToCollection(object targetResource, string propertyName, object resourceToBeAdded) 39: { 40: throw new NotImplementedException(); 41: } 42:   43: public void ClearChanges() 44: { 45: pendingUpdates.Clear(); 46: } 47:   48: public object CreateResource(string containerName, string fullTypeName) 49: { 50: var nastyWord = new NastyWord(); 51: pendingUpdates.Add(nastyWord); 52: return nastyWord; 53: } 54:   55: public void DeleteResource(object targetResource) 56: { 57: throw new NotImplementedException(); 58: } 59:   60: public object GetResource(IQueryable query, string fullTypeName) 61: { 62: throw new NotImplementedException(); 63: } 64:   65: public object GetValue(object targetResource, string propertyName) 66: { 67: throw new NotImplementedException(); 68: } 69:   70: public void RemoveReferenceFromCollection(object targetResource, string propertyName, object resourceToBeRemoved) 71: { 72: throw new NotImplementedException(); 73: } 74:   75: public object ResetResource(object resource) 76: { 77: throw new NotImplementedException(); 78: } 79:   80: public object ResolveResource(object resource) 81: { 82: return resource; 83: } 84:   85: public void SaveChanges() 86: { 87: var intersect = (from w in pendingUpdates 88: select w.Word).Intersect(from n in NastyWords 89: select n.Word); 90:   91: if (intersect.Count() > 0) 92: throw new DataServiceException(500, "duplicate entry"); 93:   94: var lines = from w in pendingUpdates 95: select w.Word; 96:   97: File.AppendAllLines(pathToFile, 98: lines, 99: Encoding.UTF8); 100:   101: pendingUpdates.Clear(); 102:   103: UpdateFromSource(); 104: } 105:   106: public void SetReference(object targetResource, string propertyName, object propertyValue) 107: { 108: throw new NotImplementedException(); 109: } 110:   111: public void SetValue(object targetResource, string propertyName, object propertyValue) 112: { 113: targetResource.GetType().GetProperty(propertyName).SetValue(targetResource, propertyValue, null); 114: } 115: } 116:   117: public class NastyWords : DataService<NastyWordsDataSource> 118: { 119: // This method is called only once to initialize service-wide policies. 120: public static void InitializeService(DataServiceConfiguration config) 121: { 122: config.SetEntitySetAccessRule("*", EntitySetRights.AllRead | EntitySetRights.WriteAppend); 123: config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; 124: } 125: } 126: } Next time we’ll allow removing nasty words. Enjoy!

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• Passing a parameter so that it cannot be changed – C#

  - by nmarun

  I read this requirement of not allowing a user to change the value of a property passed as a parameter to a method. In C++, as far as I could recall (it’s been over 10 yrs, so I had to refresh memory), you can pass ‘const’ to a function parameter and this ensures that the parameter cannot be changed inside the scope of the function. There’s no such direct way of doing this in C#, but that does not mean it cannot be done!! Ok, so this ‘not-so-direct’ technique depends on the type of the parameter – a simple property or a collection. Parameter as a simple property: This is quite easy (and you might have guessed it already). Bulent Ozkir clearly explains how this can be done here. Parameter as a collection property: Obviously the above does not work if the parameter is a collection of some type. Let’s dig-in. Suppose I need to create a collection of type KeyTitle as defined below. 1: public class KeyTitle 2: { 3: public int Key { get; set; } 4: public string Title { get; set; } 5: } My class is declared as below: 1: public class Class1 2: { 3: public Class1() 4: { 5: MyKeyTitleList = new List<KeyTitle>(); 6: } 7: 8: public List<KeyTitle> MyKeyTitleList { get; set; } 9: public ReadOnlyCollection<KeyTitle> ReadonlyKeyTitleCollection 10: { 11: // .AsReadOnly creates a ReadOnlyCollection<> type 12: get { return MyKeyTitleList.AsReadOnly(); } 13: } 14: } See the .AsReadOnly() method used in the second property? As MSDN says it: “Returns a read-only IList<T> wrapper for the current collection.” Knowing this, I can implement my code as: 1: public static void Main() 2: { 3: Class1 class1 = new Class1(); 4: class1.MyKeyTitleList.Add(new KeyTitle { Key = 1, Title = "abc" }); 5: class1.MyKeyTitleList.Add(new KeyTitle { Key = 2, Title = "def" }); 6: class1.MyKeyTitleList.Add(new KeyTitle { Key = 3, Title = "ghi" }); 7: class1.MyKeyTitleList.Add(new KeyTitle { Key = 4, Title = "jkl" }); 8:  9: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 10:  11: Console.ReadLine(); 12: } 13:  14: private static void TryToModifyCollection(ReadOnlyCollection<KeyTitle> readOnlyCollection) 15: { 16: // can only read 17: for (int i = 0; i < readOnlyCollection.Count; i++) 18: { 19: Console.WriteLine("{0} - {1}", readOnlyCollection[i].Key, readOnlyCollection[i].Title); 20: } 21: // Add() - not allowed 22: // even the indexer does not have a setter 23: } The output is as expected: The below image shows two things. In the first line, I’ve tried to access an element in my read-only collection through an indexer. It shows that the ReadOnlyCollection<> does not have a setter on the indexer. The second line tells that there’s no ‘Add()’ method for this type of collection. The capture below shows there’s no ‘Remove()’ method either, there-by eliminating all ways of modifying a collection. Mission accomplished… right? Now, even if you have a collection of different type, all you need to do is to somehow cast (used loosely) it to a List<> and then do a .AsReadOnly() to get a ReadOnlyCollection of your custom collection type. As an example, if you have an IDictionary<int, string>, you can create a List<T> of this type with a wrapper class (KeyTitle in our case). 1: public IDictionary<int, string> MyDictionary { get; set; } 2:  3: public ReadOnlyCollection<KeyTitle> ReadonlyDictionary 4: { 5: get 6: { 7: return (from item in MyDictionary 8: select new KeyTitle 9: { 10: Key = item.Key, 11: Title = item.Value, 12: }).ToList().AsReadOnly(); 13: } 14: } Cool huh? Just one thing you need to know about the .AsReadOnly() method is that the only way to modify your ReadOnlyCollection<> is to modify the original collection. So doing: 1: public static void Main() 2: { 3: Class1 class1 = new Class1(); 4: class1.MyKeyTitleList.Add(new KeyTitle { Key = 1, Title = "abc" }); 5: class1.MyKeyTitleList.Add(new KeyTitle { Key = 2, Title = "def" }); 6: class1.MyKeyTitleList.Add(new KeyTitle { Key = 3, Title = "ghi" }); 7: class1.MyKeyTitleList.Add(new KeyTitle { Key = 4, Title = "jkl" }); 8: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 9:  10: Console.WriteLine(); 11:  12: class1.MyKeyTitleList.Add(new KeyTitle { Key = 5, Title = "mno" }); 13: class1.MyKeyTitleList[2] = new KeyTitle{Key = 3, Title = "GHI"}; 14: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 15:  16: Console.ReadLine(); 17: } Gives me the output of: See that the second element’s Title is changed to upper-case and the fifth element also gets displayed even though we’re still looping through the same ReadOnlyCollection<KeyTitle>. Verdict: Now you know of a way to implement ‘Method(const param1)’ in your code!

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• C#/.NET Little Wonders: Interlocked Read() and Exchange()

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Last time we discussed the Interlocked class and its Add(), Increment(), and Decrement() methods which are all useful for updating a value atomically by adding (or subtracting).  However, this begs the question of how do we set and read those values atomically as well? Read() – Read a value atomically Let’s begin by examining the following code: 1: public class Incrementor 2: { 3: private long _value = 0; 4:  5: public long Value { get { return _value; } } 6:  7: public void Increment() 8: { 9: Interlocked.Increment(ref _value); 10: } 11: } 12:  It uses an interlocked increment, as we discuss in my previous post (here), so we know that the increment will be thread-safe.  But, to realize what’s potentially wrong we have to know a bit about how atomic reads are in 32 bit and 64 bit .NET environments. When you are dealing with an item smaller or equal to the system word size (such as an int on a 32 bit system or a long on a 64 bit system) then the read is generally atomic, because it can grab all of the bits needed at once.  However, when dealing with something larger than the system word size (reading a long on a 32 bit system for example), it cannot grab the whole value at once, which can lead to some problems since this read isn’t atomic. For example, this means that on a 32 bit system we may read one half of the long before another thread increments the value, and the other half of it after the increment.  To protect us from reading an invalid value in this manner, we can do an Interlocked.Read() to force the read to be atomic (of course, you’d want to make sure any writes or increments are atomic also): 1: public class Incrementor 2: { 3: private long _value = 0; 4:  5: public long Value 6: { 7: get { return Interlocked.Read(ref _value); } 8: } 9:  10: public void Increment() 11: { 12: Interlocked.Increment(ref _value); 13: } 14: } Now we are guaranteed that we will read the 64 bit value atomically on a 32 bit system, thus ensuring our thread safety (assuming all other reads, writes, increments, etc. are likewise protected).  Note that as stated before, and according to the MSDN (here), it isn’t strictly necessary to use Interlocked.Read() for reading 64 bit values on 64 bit systems, but for those still working in 32 bit environments, it comes in handy when dealing with long atomically. Exchange() – Exchanges two values atomically Exchange() lets us store a new value in the given location (the ref parameter) and return the old value as a result. So just as Read() allows us to read atomically, one use of Exchange() is to write values atomically.  For example, if we wanted to add a Reset() method to our Incrementor, we could do something like this: 1: public void Reset() 2: { 3: _value = 0; 4: } But the assignment wouldn’t be atomic on 32 bit systems, since the word size is 32 bits and the variable is a long (64 bits).  Thus our assignment could have only set half the value when a threaded read or increment happens, which would put us in a bad state. So instead, we could write Reset() like this: 1: public void Reset() 2: { 3: Interlocked.Exchange(ref _value, 0); 4: } And we’d be safe again on a 32 bit system. But this isn’t the only reason Exchange() is valuable.  The key comes in realizing that Exchange() doesn’t just set a new value, it returns the old as well in an atomic step.  Hence the name “exchange”: you are swapping the value to set with the stored value. So why would we want to do this?  Well, anytime you want to set a value and take action based on the previous value.  An example of this might be a scheme where you have several tasks, and during every so often, each of the tasks may nominate themselves to do some administrative chore.  Perhaps you don’t want to make this thread dedicated for whatever reason, but want to be robust enough to let any of the threads that isn’t currently occupied nominate itself for the job.  An easy and lightweight way to do this would be to have a long representing whether someone has acquired the “election” or not.  So a 0 would indicate no one has been elected and 1 would indicate someone has been elected. We could then base our nomination strategy as follows: every so often, a thread will attempt an Interlocked.Exchange() on the long and with a value of 1.  The first thread to do so will set it to a 1 and return back the old value of 0.  We can use this to show that they were the first to nominate and be chosen are thus “in charge”.  Anyone who nominates after that will attempt the same Exchange() but will get back a value of 1, which indicates that someone already had set it to a 1 before them, thus they are not elected. Then, the only other step we need take is to remember to release the election flag once the elected thread accomplishes its task, which we’d do by setting the value back to 0.  In this way, the next thread to nominate with Exchange() will get back the 0 letting them know they are the new elected nominee. Such code might look like this: 1: public class Nominator 2: { 3: private long _nomination = 0; 4: public bool Elect() 5: { 6: return Interlocked.Exchange(ref _nomination, 1) == 0; 7: } 8: public bool Release() 9: { 10: return Interlocked.Exchange(ref _nomination, 0) == 1; 11: } 12: } There’s many ways to do this, of course, but you get the idea.  Running 5 threads doing some “sleep” work might look like this: 1: var nominator = new Nominator(); 2: var random = new Random(); 3: Parallel.For(0, 5, i => 4: { 5:  6: for (int j = 0; j < _iterations; ++j) 7: { 8: if (nominator.Elect()) 9: { 10: // elected 11: Console.WriteLine("Elected nominee " + i); 12: Thread.Sleep(random.Next(100, 5000)); 13: nominator.Release(); 14: } 15: else 16: { 17: // not elected 18: Console.WriteLine("Did not elect nominee " + i); 19: } 20: // sleep before check again 21: Thread.Sleep(1000); 22: } 23: }); And would spit out results like: 1: Elected nominee 0 2: Did not elect nominee 2 3: Did not elect nominee 1 4: Did not elect nominee 4 5: Did not elect nominee 3 6: Did not elect nominee 3 7: Did not elect nominee 1 8: Did not elect nominee 2 9: Did not elect nominee 4 10: Elected nominee 3 11: Did not elect nominee 2 12: Did not elect nominee 1 13: Did not elect nominee 4 14: Elected nominee 0 15: Did not elect nominee 2 16: Did not elect nominee 4 17: ... Another nice thing about the Interlocked.Exchange() is it can be used to thread-safely set pretty much anything 64 bits or less in size including references, pointers (in unsafe mode), floats, doubles, etc.  Summary So, now we’ve seen two more things we can do with Interlocked: reading and exchanging a value atomically.  Read() and Exchange() are especially valuable for reading/writing 64 bit values atomically in a 32 bit system.  Exchange() has value even beyond simply atomic writes by using the Exchange() to your advantage, since it reads and set the value atomically, which allows you to do lightweight nomination systems. There’s still a few more goodies in the Interlocked class which we’ll explore next time! Technorati Tags: C#,CSharp,.NET,Little Wonders,Interlocked

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• How does gluLookAt work?

  - by Chan

  From my understanding, gluLookAt( eye_x, eye_y, eye_z, center_x, center_y, center_z, up_x, up_y, up_z ); is equivalent to: glRotatef(B, 0.0, 0.0, 1.0); glRotatef(A, wx, wy, wz); glTranslatef(-eye_x, -eye_y, -eye_z); But when I print out the ModelView matrix, the call to glTranslatef() doesn't seem to work properly. Here is the code snippet: #include <stdlib.h> #include <stdio.h> #include <GL/glut.h> #include <iomanip> #include <iostream> #include <string> using namespace std; static const int Rx = 0; static const int Ry = 1; static const int Rz = 2; static const int Ux = 4; static const int Uy = 5; static const int Uz = 6; static const int Ax = 8; static const int Ay = 9; static const int Az = 10; static const int Tx = 12; static const int Ty = 13; static const int Tz = 14; void init() { glClearColor(0.0, 0.0, 0.0, 0.0); glEnable(GL_DEPTH_TEST); glShadeModel(GL_SMOOTH); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); GLfloat lmodel_ambient[] = { 0.8, 0.0, 0.0, 0.0 }; glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient); } void displayModelviewMatrix(float MV[16]) { int SPACING = 12; cout << left; cout << "\tMODELVIEW MATRIX\n"; cout << "--------------------------------------------------" << endl; cout << setw(SPACING) << "R" << setw(SPACING) << "U" << setw(SPACING) << "A" << setw(SPACING) << "T" << endl; cout << "--------------------------------------------------" << endl; cout << setw(SPACING) << MV[Rx] << setw(SPACING) << MV[Ux] << setw(SPACING) << MV[Ax] << setw(SPACING) << MV[Tx] << endl; cout << setw(SPACING) << MV[Ry] << setw(SPACING) << MV[Uy] << setw(SPACING) << MV[Ay] << setw(SPACING) << MV[Ty] << endl; cout << setw(SPACING) << MV[Rz] << setw(SPACING) << MV[Uz] << setw(SPACING) << MV[Az] << setw(SPACING) << MV[Tz] << endl; cout << setw(SPACING) << MV[3] << setw(SPACING) << MV[7] << setw(SPACING) << MV[11] << setw(SPACING) << MV[15] << endl; cout << "--------------------------------------------------" << endl; cout << endl; } void reshape(int w, int h) { float ratio = static_cast<float>(w)/h; glViewport(0, 0, w, h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(45.0, ratio, 1.0, 425.0); } void draw() { float m[16]; glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glGetFloatv(GL_MODELVIEW_MATRIX, m); gluLookAt( 300.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f ); glColor3f(1.0, 0.0, 0.0); glutSolidCube(100.0); glGetFloatv(GL_MODELVIEW_MATRIX, m); displayModelviewMatrix(m); glutSwapBuffers(); } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH); glutInitWindowSize(400, 400); glutInitWindowPosition(100, 100); glutCreateWindow("Demo"); glutReshapeFunc(reshape); glutDisplayFunc(draw); init(); glutMainLoop(); return 0; } No matter what value I use for the eye vector: 300, 0, 0 or 0, 300, 0 or 0, 0, 300 the translation vector is the same, which doesn't make any sense because the order of code is in backward order so glTranslatef should run first, then the 2 rotations. Plus, the rotation matrix, is completely independent of the translation column (in the ModelView matrix), then what would cause this weird behavior? Here is the output with the eye vector is (0.0f, 300.0f, 0.0f) MODELVIEW MATRIX -------------------------------------------------- R U A T -------------------------------------------------- 0 0 0 0 0 0 0 0 0 1 0 -300 0 0 0 1 -------------------------------------------------- I would expect the T column to be (0, -300, 0)! So could anyone help me explain this? The implementation of gluLookAt from http://www.mesa3d.org void GLAPIENTRY gluLookAt(GLdouble eyex, GLdouble eyey, GLdouble eyez, GLdouble centerx, GLdouble centery, GLdouble centerz, GLdouble upx, GLdouble upy, GLdouble upz) { float forward[3], side[3], up[3]; GLfloat m[4][4]; forward[0] = centerx - eyex; forward[1] = centery - eyey; forward[2] = centerz - eyez; up[0] = upx; up[1] = upy; up[2] = upz; normalize(forward); /* Side = forward x up */ cross(forward, up, side); normalize(side); /* Recompute up as: up = side x forward */ cross(side, forward, up); __gluMakeIdentityf(&m[0][0]); m[0][0] = side[0]; m[1][0] = side[1]; m[2][0] = side[2]; m[0][1] = up[0]; m[1][1] = up[1]; m[2][1] = up[2]; m[0][2] = -forward[0]; m[1][2] = -forward[1]; m[2][2] = -forward[2]; glMultMatrixf(&m[0][0]); glTranslated(-eyex, -eyey, -eyez); }

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• Azure Task Scheduling Options

  - by charlie.mott

  Currently, the Azure PaaS does not offer a distributed\resilient task scheduling service.  If you do want to host a task scheduling product\solution off-premise (and ideally use Azure), what are your options? PaaS Option 1: Worker Roles Use a worker role to schedule and execute actions at specific time periods.  There are a few frameworks available to assist with this: http://azuretoolkit.codeplex.com https://github.com/Lokad/lokad-cloud/wiki/TaskScheduler http://blog.smarx.com/posts/building-a-task-scheduler-in-windows-azure - This addresses a slightly different set of requirements. It’s a more dynamic approach for queuing up tasks, but not repeatable tasks (e.g. daily). I found the Azure Toolkit option the most simple to implement.  Step 1 : Create a domain entity implementing IJob for each job to schedule.  In this sample, I asynchronously call a WCF service method. 1: namespace Acme.WorkerRole.Jobs 2: { 3: using AzureToolkit; 4: using ScheduledTasksService; 5: 6: public class UploadEmployeesJob : IJob 7: { 8: public void Run() 9: { 10: // Call Tasks Service 11: var client = new ScheduledTasksServiceClient("BasicHttpBinding_IScheduledTasksService"); 12: client.UploadEmployees(); 13: client.Close(); 14: } 15: } 16: } Step 2 : In the worker role run method, add the jobs to the toolkit engine. 1: namespace Acme.WorkerRole 2: { 3: using AzureToolkit.Engine; 4: using Jobs; 5:   6: public class WorkerRole : WorkerRoleEntryPoint 7: { 8: public override void Run() 9: { 10: var engine = new CloudEngine(); 11:   12: // Add Scheduled Jobs (using CronJob syntax - see http://www.adminschoice.com/crontab-quick-reference). 13:   14: // 1. Upload Employee job - 8.00 PM every weekday (Mon-Fri) 15: engine.WithJobScheduler().ScheduleJob<UploadEmployeesJob>(c => { c.CronSchedule = "0 20 * * 1-5"; }); 16: // 2. Purge Data job - 10 AM every Saturday 17: engine.WithJobScheduler().ScheduleJob<PurgeDataJob>(c => { c.CronSchedule = "0 10 * * 6"; }); 18: // 3. Process Exceptions job - Every 5 minutes 19: engine.WithJobScheduler().ScheduleJob<ProcessExceptionsJob>(c => { c.CronSchedule = "*/5 * * * *"; }); 20:   21: engine.Run(); 22: base.Run(); 23: } 24: } 25: } Pros Cons Azure Toolkit option is simple to implement. For the AzureToolkit option, you are limited to a single worker role.  Otherwise, the jobs will be executed multiple times, once for each worker role instance.   Paying for a continuously running worker role, even if it just processes a single job once a week.  If you only have a few scheduled tasks to run calling asynchronous services hosted in different web roles, an extra small worker role likely to be sufficient.  However, for an extra small worker role this still costs $14.40/month (03/09/2012). Option 2: Use Scheduled Task on Azure Web Role calling a console app Setup a Windows Scheduled Task on the Azure Web Role. This calls a console application that calls the WCF service methods that run the task actions. This design is described here: http://www.ronaldwidha.net/2011/02/23/cron-job-on-azure-using-scheduled-task-on-a-web-role-to-replace-azure-worker-role-for-background-job/ http://www.voiceoftech.com/swhitley/index.php/2011/07/windows-azure-task-scheduler/ http://devlicio.us/blogs/vinull/archive/2011/10/23/moving-to-azure-worker-roles-for-nothing-and-tasks-for-free.aspx Pros Cons Fairly easy to implement. Supportability - I RDC’ed onto the Azure server and stopped the scheduled task. I then rebooted the machine and the task was re-started. I also tried deleting the task and rebooting, the same thing occurred. The only way to permanently guarantee that a task is disabled is to do a fresh deployment. I think this is a major supportability concern.   Saleability - multiple instances would trigger multiple tasks. You can only have one instance for the scheduled task web role. The guidance implements setup of the scheduled task as part of a web role instance. But if you have more than one instance in a web role, the task will be triggered multiple times for each scheduled action (once per machine). Workaround: If we wanted to use scheduled tasks for another client with a saleable WCF service, then we could include the console & tasks scripts in a separate web role (e.g. a empty WCF service with no real purpose to it). SaaS Option 3: Azure Marketplace I thought that someone might be offering this type of service via the Azure marketplace. At the point of writing this blog post, I did not find anyone doing so. https://datamarket.azure.com/ Pros Cons   Nobody currently offers this on the Azure Marketplace. Option 4: Online Job Scheduling Service Provider There are plenty of online providers that offer this type of service on a pay-as-you-go approach.  Some of these are free for small usage.   Many of these providers are listed here: http://en.wikipedia.org/wiki/Webcron Pros Cons No bespoke development for scheduler. Reliance on third party. IaaS Option 5: Setup Scheduling Software on Azure IaaS VM’s One of job scheduling software offerings could be installed and configured on Azure VM’s.  A list of software options is listed here: http://en.wikipedia.org/wiki/List_of_job_scheduler_software Pros Cons Enterprise distributed\resilient task scheduling service VM Setup and maintenance   Software Licence Costs Option 6: VM Gallery A the time of writing this blog post, I did not spot a VM in the gallery that included pre-installation of any of the above software options. Pros Cons   No current VM template. Summary For my current project that had a small handful of tasks to schedule with a limited project budget I chose option 1 (a worker role using the Azure Toolkit to schedule tasks).  If I was building an enterprise scale solution for the future, options 4 and 5 are currently worthy of consideration. Hopefully, Microsoft will include tasks scheduling in the future as part of their PaaS offerings.

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• Box2D blocky map. Body, Fixtures a huge map and performance

  - by Solom

  Right now I'm still in the planning phase of a my very first game. I'm creating a "Minecraft"-like game in 2D that features blocks that can be destroyed as well as players moving around the map. For creating the map I chose a 2D-Array of Integers that represent the Block ID. For testing purposes I created a huge map (16348 * 256) and in my prototype that didn't use Box2D everything worked like a charm. I only rendered those blocks that where within the bounds of my camera and got 60 fps straight. The problem started when I decided to use an existing physics-solution rather than implementing my own one. What I had was basically simple hitboxes around the blocks and then I had to manually check if the player collided with any of those in his neighborhood. For more advanced physics as well as the collision detection I want to switch over to Box2D. The problem I have right now is ... how to go about the bodies? I mean, the blocks are of a static bodytype. They don't move on their own, they just are there to be collided with. But as far as I can see it, every block needs his own body with a rectangular fixture attached to it, so as to be destroyable. But for a huge map such as mine, this turns out to be a real performance bottle-neck. (In fact even a rather small map [compared to the other] of 1024*256 is unplayable.) I mean I create thousands of thousands of blocks. Even if I just render those that are in my immediate neighborhood there are hundreds of them and (at least with the debugRenderer) I drop to 1 fps really quickly (on my own "monster machine"). I thought about strategies like creating just one body, attaching multiple fixtures and only if a fixture got hit, separate it from the body, create a new one and destroy it, but this didn't turn out quite as successful as hoped. (In fact the core just dumps. Ah hello C! I really missed you :X) Here is the code: public class Box2DGameScreen implements Screen { private World world; private Box2DDebugRenderer debugRenderer; private OrthographicCamera camera; private final float TIMESTEP = 1 / 60f; // 1/60 of a second -> 1 frame per second private final int VELOCITYITERATIONS = 8; private final int POSITIONITERATIONS = 3; private Map map; private BodyDef blockBodyDef; private FixtureDef blockFixtureDef; private BodyDef groundDef; private Body ground; private PolygonShape rectangleShape; @Override public void show() { world = new World(new Vector2(0, -9.81f), true); debugRenderer = new Box2DDebugRenderer(); camera = new OrthographicCamera(); // Pixel:Meter = 16:1 // Body definition BodyDef ballDef = new BodyDef(); ballDef.type = BodyDef.BodyType.DynamicBody; ballDef.position.set(0, 1); // Fixture definition FixtureDef ballFixtureDef = new FixtureDef(); ballFixtureDef.shape = new CircleShape(); ballFixtureDef.shape.setRadius(.5f); // 0,5 meter ballFixtureDef.restitution = 0.75f; // between 0 (not jumping up at all) and 1 (jumping up the same amount as it fell down) ballFixtureDef.density = 2.5f; // kg / m² ballFixtureDef.friction = 0.25f; // between 0 (sliding like ice) and 1 (not sliding) // world.createBody(ballDef).createFixture(ballFixtureDef); groundDef = new BodyDef(); groundDef.type = BodyDef.BodyType.StaticBody; groundDef.position.set(0, 0); ground = world.createBody(groundDef); this.map = new Map(20, 20); rectangleShape = new PolygonShape(); // rectangleShape.setAsBox(1, 1); blockFixtureDef = new FixtureDef(); // blockFixtureDef.shape = rectangleShape; blockFixtureDef.restitution = 0.1f; blockFixtureDef.density = 10f; blockFixtureDef.friction = 0.9f; } @Override public void render(float delta) { Gdx.gl.glClearColor(1, 1, 1, 1); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); debugRenderer.render(world, camera.combined); drawMap(); world.step(TIMESTEP, VELOCITYITERATIONS, POSITIONITERATIONS); } private void drawMap() { for(int a = 0; a < map.getHeight(); a++) { /* if(camera.position.y - (camera.viewportHeight/2) > a) continue; if(camera.position.y - (camera.viewportHeight/2) < a) break; */ for(int b = 0; b < map.getWidth(); b++) { /* if(camera.position.x - (camera.viewportWidth/2) > b) continue; if(camera.position.x - (camera.viewportWidth/2) < b) break; */ /* blockBodyDef = new BodyDef(); blockBodyDef.type = BodyDef.BodyType.StaticBody; blockBodyDef.position.set(b, a); world.createBody(blockBodyDef).createFixture(blockFixtureDef); */ PolygonShape rectangleShape = new PolygonShape(); rectangleShape.setAsBox(1, 1, new Vector2(b, a), 0); blockFixtureDef.shape = rectangleShape; ground.createFixture(blockFixtureDef); rectangleShape.dispose(); } } } @Override public void resize(int width, int height) { camera.viewportWidth = width / 16; camera.viewportHeight = height / 16; camera.update(); } @Override public void hide() { dispose(); } @Override public void pause() { } @Override public void resume() { } @Override public void dispose() { world.dispose(); debugRenderer.dispose(); } } As you can see I'm facing multiple problems here. I'm not quite sure how to check for the bounds but also if the map is bigger than 24*24 like 1024*256 Java just crashes -.-. And with 24*24 I get like 9 fps. So I'm doing something really terrible here, it seems and I assume that there most be a (much more performant) way, even with Box2D's awesome physics. Any other ideas? Thanks in advance!

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