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• Rockmelt, the technology adoption model, and Facebook's spare internet

  - by Roger Hart

  Regardless of how good it is, you'd have to have a heart of stone not to make snide remarks about Rockmelt. After all, on the surface it looks a lot like some people spent two years building a browser instead of just bashing out a Chrome extension over a wet weekend. It probably does some more stuff. I don't know for sure because artificial scarcity is cool, apparently, so the "invitation" is still in the post*. I may in fact never know for sure, because I'm not wild about Facebook sign-in as a prerequisite for anything. From the video, and some initial reviews, my early reaction was: I have a browser, I have a Twitter client; what on earth is this for? The answer, of course, is "not me". Rockmelt is, in a way, quite audacious. Oh, sure, on launch day it's Bay Area bar-chat for the kids with no lenses in their retro specs and trousers that give you deep-vein thrombosis, but it's not really about them. Likewise,  Facebook just launched Google Wave, or something. And all the tech snobbery and scorn packed into describing it that way is irrelevant next to what they're doing with their platform. Here's something I drew in MS Paint** because I don't want to get sued: (see: The technology adoption lifecycle) A while ago in the Guardian, John Lanchester dusted off the idiom that "technology is stuff that doesn't work yet". The rest of the article would be quite interesting if it wasn't largely about MySpace, and he's sort of got a point. If you bolt on the sentiment that risk-averse businessmen like things that work, you've got the essence of Crossing the Chasm. Products for the mainstream market don't look much like technology. Think for  a second about early (1980s ish) hi-fi systems, with all the knobs and fiddly bits, their ostentatious technophile aesthetic. Then consider their sleeker and less (or at least less conspicuously) functional successors in the 1990s. The theory goes that innovators and early adopters like technology, it's a hobby in itself. The rest of the humans seem to like magic boxes with very few buttons that make stuff happen and never trouble them about why. Personally, I consider Apple's maddening insistence that iTunes is an acceptable way to move files around to be more or less morally unacceptable. Most people couldn't care less. Hence Rockmelt, and hence Facebook's continued growth. Rockmelt looks pointless to me, because I aggregate my social gubbins with Digsby, or use TweetDeck. But my use case is different and so are my enthusiasms. If I want to share photos, I'll use Flickr - but Facebook has photo sharing. If I want a short broadcast message, I'll use Twitter - Facebook has status updates. If I want to sell something with relatively little hassle, there's eBay - or Facebook marketplace. YouTube - check, FB Video. Email - messaging. Calendaring apps, yeah there are loads, or FB Events. What if I want to host a simple web page? Sure, they've got pages. Also Notes for blogging, and more games than I can count. This stuff is right there, where millions and millions of users are already, and for what they need it just works. It's not about me, because I'm not in the big juicy area under the curve. It's what 1990s portal sites could never have dreamed of achieving. Facebook is AOL on speed, crack, and some designer drugs it had specially imported from the future. It's a n00b-friendly gateway to the internet that just happens to serve up all the things you want to do online, right where you are. Oh, and everybody else is there too. The price of having all this and the social graph too is that you have all of this, and the social graph too. But plenty of folks have more incisive things to say than me about the whole privacy shebang, and it's not really what I'm talking about. Facebook is maintaining a vast, and fairly fully-featured training-wheels internet. And it makes up a large proportion of the online experience for a lot of people***. It's the entire web (2.0?) experience for the early and late majority. And sure, no individual bit of it is quite as slick or as fully-realised as something like Flickr (which wows me a bit every time I use it. Those guys are good at the web), but it doesn't have to be. It has to be unobtrusively good enough for the regular humans. It has to not feel like technology. This is what Rockmelt sort of is. You're online, you want something nebulously social, and you don't want to faff about with, say, Twitter clients. Wow! There it is on a really distracting sidebar, right in your browser. No effort! Yeah - fish nor fowl, much? It might work, I guess. There may be a demographic who want their social web experience more simply than tech tinkering, and who aren't just getting it from Facebook (or, for that matter, mobile devices). But I'd be surprised. Rockmelt feels like an attempt to grab a slice of Facebook-style "Look! It's right here, where you already are!", but it's still asking the mature market to install a new browser. Presumably this is where that Facebook sign-in predicate comes in handy, though it'll take some potent awareness marketing to make it fly. Meanwhile, Facebook quietly has the entire rest of the internet as a product management resource, and can continue to give most of the people most of what they want. Something that has not gone un-noticed in its potential to look a little sinister. But heck, they might even make Google Wave popular.     *This was true last week when I drafted this post. I got an invite subsequently, hence the screenshot. **MS Paint is no fun any more. It's actually good in Windows 7. Farewell ironically-shonky diagrams. *** It's also behind a single sign-in, lending a veneer of confidence, and partially solving the problem of usernames being crummy unique identifiers. I'll be blogging about that at some point.

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• ASP.NET MVC JavaScript Routing

  - by zowens

  Have you ever done this sort of thing in your ASP.NET MVC view? The weird thing about this isn’t the alert function, it’s the code block containing the Url formation using the ASP.NET MVC UrlHelper. The terrible thing about this experience is the obvious lack of IntelliSense and this ugly inline JavaScript code. Inline JavaScript isn’t portable to other pages beyond the current page of execution. It is generally considered bad practice to use inline JavaScript in your public-facing pages. How ludicrous would it be to copy and paste the entire jQuery code base into your pages…? Not something you’d ever consider doing. The problem is that your URLs have to be generated by ASP.NET at runtime and really can’t be copied to your JavaScript code without some trickery. How about this? Does the hard-coded URL bother you? It really bothers me. The typical solution to this whole routing in JavaScript issue is to just hard-code your URLs into your JavaScript files and call it done. But what if your URLs change? You have to now go an track down the places in JavaScript and manually replace them. What if you get the pattern wrong? Do you have tests around it? This isn’t something you should have to worry about.   The Solution To Our Problems The solution is to port routing over to JavaScript. Does that sound daunting to you? It’s actually not very hard, but I decided to create my own generator that will do all the work for you. What I have created is a very basic port of the route formation feature of ASP.NET routing. It will generate the formatted URLs based on your routing patterns. Here’s how you’d do this: Does that feel familiar? It looks a lot like something you’d do inside of your ASP.NET MVC views… but this is inside of a JavaScript file… just a plain ol’ .js file.  Your first question might be why do you have to have that “.toUrl()” thing. The reason is that I wanted to make POST and GET requests dead simple. Here’s how you’d do a POST request (and the same would work with a GET request):   The first parameter is extra data passed to the post request and the second parameter is a function that handles the success of the POST request. If you’re familiar with jQuery’s Ajax goodness, you’ll know how to use it. (if not, check out http://api.jquery.com/jQuery.Post/ and the parameters are essentially the same). But we still haven’t gotten rid of the magic strings. We still have controller names and action names represented as strings. This is going to blow your mind… If you’ve seen T4MVC, this will look familiar. We’re essentially doing the same sort of thing with my JavaScript router, but we’re porting the concept to JavaScript. The good news is that parameters to the controllers are directly reflected in the action function, just like T4MVC. And the even better news… IntlliSense is easily transferred to the JavaScript version if you’re using Visual Studio as your JavaScript editor. The additional data parameter gives you the ability to pass extra routing data to the URL formatter.   About the Magic You may be wondering how this all work. It’s actually quite simple. I’ve built a simple jQuery pluggin (called routeManager) that hangs off the main jQuery namespace and routes all the URLs. Every time your solution builds, a routing file will be generated with this pluggin, all your route and controller definitions along with your documentation. Then by the power of Visual Studio, you get some really slick IntelliSense that is hard to live without. But there are a few steps you have to take before this whole thing is going to work. First and foremost, you need a reference to the JsRouting.Core.dll to your projects containing controllers or routes. Second, you have to specify your routes in a bit of a non-standard way. See, we can’t just pull routes out of your App_Start in your Global.asax. We force you to build a route source like this: The way we determine the routes is by pulling in all RouteSources and generating routes based upon the mapped routes. There are various reasons why we can’t use RouteCollection (different post for another day)… but in this case, you get the same route mapping experience. Converting the RouteSource to a RouteCollection is trivial (there’s an extension method for that). Next thing you have to do is generate a documentation XML file. This is done by going to the project settings, going to the build tab and clicking the checkbox. (this isn’t required, but nice to have). The final thing you need to do is hook up the generation mechanism. Pop open your project file and look for the AfterBuild step. Now change the build step task to look like this: The “PathToOutputExe” is the path to the JsRouting.Output.exe file. This will change based on where you put the EXE. The “PathToOutputJs” is a path to the output JavaScript file. The “DicrectoryOfAssemblies” is a path to the directory containing controller and routing DLLs. The JsRouting.Output.exe executable pulls in all these assemblies and scans them for controllers and route sources.   Now that wasn’t too bad, was it :)   The State of the Project This is definitely not complete… I have a lot of plans for this little project of mine. For starters, I need to look at the generation mechanism. Either I will be creating a utility that will do the project file manipulation or I will go a different direction. I’d like some feedback on this if you feel partial either way. Another thing I don’t support currently is areas. While this wouldn’t be too hard to support, I just don’t use areas and I wanted something up quickly (this is, after all, for a current project of mine). I’ll be adding support shortly. There are a few things that I haven’t covered in this post that I will most certainly be covering in another post, such as routing constraints and how these will be translated to JavaScript. I decided to open source this whole thing, since it’s a nice little utility I think others should really be using. Currently we’re using ASP.NET MVC 2, but it should work with MVC 3 as well. I’ll upgrade it as soon as MVC 3 is released. Along those same lines, I’m investigating how this could be put on the NuGet feed. Show me the Bits! OK, OK! The code is posted on my GitHub account. Go nuts. Tell me what you think. Tell me what you want. Tell me that you hate it. All feedback is welcome! https://github.com/zowens/ASP.NET-MVC-JavaScript-Routing

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• Movement prediction for non-shooters

  - by ShadowChaser

  I'm working on an isometric 2D game with moderate-scale multiplayer, approximately 20-30 players connected at once to a persistent server. I've had some difficulty getting a good movement prediction implementation in place. Physics/Movement The game doesn't have a true physics implementation, but uses the basic principles to implement movement. Rather than continually polling input, state changes (ie/ mouse down/up/move events) are used to change the state of the character entity the player is controlling. The player's direction (ie/ north-east) is combined with a constant speed and turned into a true 3D vector - the entity's velocity. In the main game loop, "Update" is called before "Draw". The update logic triggers a "physics update task" that tracks all entities with a non-zero velocity uses very basic integration to change the entities position. For example: entity.Position += entity.Velocity.Scale(ElapsedTime.Seconds) (where "Seconds" is a floating point value, but the same approach would work for millisecond integer values). The key point is that no interpolation is used for movement - the rudimentary physics engine has no concept of a "previous state" or "current state", only a position and velocity. State Change and Update Packets When the velocity of the character entity the player is controlling changes, a "move avatar" packet is sent to the server containing the entity's action type (stand, walk, run), direction (north-east), and current position. This is different from how 3D first person games work. In a 3D game the velocity (direction) can change frame to frame as the player moves around. Sending every state change would effectively transmit a packet per frame, which would be too expensive. Instead, 3D games seem to ignore state changes and send "state update" packets on a fixed interval - say, every 80-150ms. Since speed and direction updates occur much less frequently in my game, I can get away with sending every state change. Although all of the physics simulations occur at the same speed and are deterministic, latency is still an issue. For that reason, I send out routine position update packets (similar to a 3D game) but much less frequently - right now every 250ms, but I suspect with good prediction I can easily boost it towards 500ms. The biggest problem is that I've now deviated from the norm - all other documentation, guides, and samples online send routine updates and interpolate between the two states. It seems incompatible with my architecture, and I need to come up with a better movement prediction algorithm that is closer to a (very basic) "networked physics" architecture. The server then receives the packet and determines the players speed from it's movement type based on a script (Is the player able to run? Get the player's running speed). Once it has the speed, it combines it with the direction to get a vector - the entity's velocity. Some cheat detection and basic validation occurs, and the entity on the server side is updated with the current velocity, direction, and position. Basic throttling is also performed to prevent players from flooding the server with movement requests. After updating its own entity, the server broadcasts an "avatar position update" packet to all other players within range. The position update packet is used to update the client side physics simulations (world state) of the remote clients and perform prediction and lag compensation. Prediction and Lag Compensation As mentioned above, clients are authoritative for their own position. Except in cases of cheating or anomalies, the client's avatar will never be repositioned by the server. No extrapolation ("move now and correct later") is required for the client's avatar - what the player sees is correct. However, some sort of extrapolation or interpolation is required for all remote entities that are moving. Some sort of prediction and/or lag-compensation is clearly required within the client's local simulation / physics engine. Problems I've been struggling with various algorithms, and have a number of questions and problems: Should I be extrapolating, interpolating, or both? My "gut feeling" is that I should be using pure extrapolation based on velocity. State change is received by the client, client computes a "predicted" velocity that compensates for lag, and the regular physics system does the rest. However, it feels at odds to all other sample code and articles - they all seem to store a number of states and perform interpolation without a physics engine. When a packet arrives, I've tried interpolating the packet's position with the packet's velocity over a fixed time period (say, 200ms). I then take the difference between the interpolated position and the current "error" position to compute a new vector and place that on the entity instead of the velocity that was sent. However, the assumption is that another packet will arrive in that time interval, and it's incredibly difficult to "guess" when the next packet will arrive - especially since they don't all arrive on fixed intervals (ie/ state changes as well). Is the concept fundamentally flawed, or is it correct but needs some fixes / adjustments? What happens when a remote player stops? I can immediately stop the entity, but it will be positioned in the "wrong" spot until it moves again. If I estimate a vector or try to interpolate, I have an issue because I don't store the previous state - the physics engine has no way to say "you need to stop after you reach position X". It simply understands a velocity, nothing more complex. I'm reluctant to add the "packet movement state" information to the entities or physics engine, since it violates basic design principles and bleeds network code across the rest of the game engine. What should happen when entities collide? There are three scenarios - the controlling player collides locally, two entities collide on the server during a position update, or a remote entity update collides on the local client. In all cases I'm uncertain how to handle the collision - aside from cheating, both states are "correct" but at different time periods. In the case of a remote entity it doesn't make sense to draw it walking through a wall, so I perform collision detection on the local client and cause it to "stop". Based on point #2 above, I might compute a "corrected vector" that continually tries to move the entity "through the wall" which will never succeed - the remote avatar is stuck there until the error gets too high and it "snaps" into position. How do games work around this?

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• Use a Fake Http Channel to Unit Test with HttpClient

  - by Steve Michelotti

  Applications get data from lots of different sources. The most common is to get data from a database or a web service. Typically, we encapsulate calls to a database in a Repository object and we create some sort of IRepository interface as an abstraction to decouple between layers and enable easier unit testing by leveraging faking and mocking. This works great for database interaction. However, when consuming a RESTful web service, this is is not always the best approach. The WCF Web APIs that are available on CodePlex (current drop is Preview 3) provide a variety of features to make building HTTP REST services more robust. When you download the latest bits, you’ll also find a new HttpClient which has been updated for .NET 4.0 as compared to the one that shipped for 3.5 in the original REST Starter Kit. The HttpClient currently provides the best API for consuming REST services on the .NET platform and the WCF Web APIs provide a number of extension methods which extend HttpClient and make it even easier to use. Let’s say you have a client application that is consuming an HTTP service – this could be Silverlight, WPF, or any UI technology but for my example I’ll use an MVC application: 1: using System; 2: using System.Net.Http; 3: using System.Web.Mvc; 4: using FakeChannelExample.Models; 5: using Microsoft.Runtime.Serialization; 6:   7: namespace FakeChannelExample.Controllers 8: { 9: public class HomeController : Controller 10: { 11: private readonly HttpClient httpClient; 12:   13: public HomeController(HttpClient httpClient) 14: { 15: this.httpClient = httpClient; 16: } 17:   18: public ActionResult Index() 19: { 20: var response = httpClient.Get("Person(1)"); 21: var person = response.Content.ReadAsDataContract<Person>(); 22:   23: this.ViewBag.Message = person.FirstName + " " + person.LastName; 24: 25: return View(); 26: } 27: } 28: } On line #20 of the code above you can see I’m performing an HTTP GET request to a Person resource exposed by an HTTP service. On line #21, I use the ReadAsDataContract() extension method provided by the WCF Web APIs to serialize to a Person object. In this example, the HttpClient is being passed into the constructor by MVC’s dependency resolver – in this case, I’m using StructureMap as an IoC and my StructureMap initialization code looks like this: 1: using StructureMap; 2: using System.Net.Http; 3:   4: namespace FakeChannelExample 5: { 6: public static class IoC 7: { 8: public static IContainer Initialize() 9: { 10: ObjectFactory.Initialize(x => 11: { 12: x.For<HttpClient>().Use(() => new HttpClient("http://localhost:31614/")); 13: }); 14: return ObjectFactory.Container; 15: } 16: } 17: } My controller code currently depends on a concrete instance of the HttpClient. Now I *could* create some sort of interface and wrap the HttpClient in this interface and use that object inside my controller instead – however, there are a few why reasons that is not desirable: For one thing, the API provided by the HttpClient provides nice features for dealing with HTTP services. I don’t really *want* these to look like C# RPC method calls – when HTTP services have REST features, I may want to inspect HTTP response headers and hypermedia contained within the message so that I can make intelligent decisions as to what to do next in my workflow (although I don’t happen to be doing these things in my example above) – this type of workflow is common in hypermedia REST scenarios. If I just encapsulate HttpClient behind some IRepository interface and make it look like a C# RPC method call, it will become difficult to take advantage of these types of things. Second, it could get pretty mind-numbing to have to create interfaces all over the place just to wrap the HttpClient. Then you’re probably going to have to hard-code HTTP knowledge into your code to formulate requests rather than just “following the links” that the hypermedia in a message might provide. Third, at first glance it might appear that we need to create an interface to facilitate unit testing, but actually it’s unnecessary. Even though the code above is dependent on a concrete type, it’s actually very easy to fake the data in a unit test. The HttpClient provides a Channel property (of type HttpMessageChannel) which allows you to create a fake message channel which can be leveraged in unit testing. In this case, what I want is to be able to write a unit test that just returns fake data. I also want this to be as re-usable as possible for my unit testing. I want to be able to write a unit test that looks like this: 1: [TestClass] 2: public class HomeControllerTest 3: { 4: [TestMethod] 5: public void Index() 6: { 7: // Arrange 8: var httpClient = new HttpClient("http://foo.com"); 9: httpClient.Channel = new FakeHttpChannel<Person>(new Person { FirstName = "Joe", LastName = "Blow" }); 10:   11: HomeController controller = new HomeController(httpClient); 12:   13: // Act 14: ViewResult result = controller.Index() as ViewResult; 15:   16: // Assert 17: Assert.AreEqual("Joe Blow", result.ViewBag.Message); 18: } 19: } Notice on line #9, I’m setting the Channel property of the HttpClient to be a fake channel. I’m also specifying the fake object that I want to be in the response on my “fake” Http request. I don’t need to rely on any mocking frameworks to do this. All I need is my FakeHttpChannel. The code to do this is not complex: 1: using System; 2: using System.IO; 3: using System.Net.Http; 4: using System.Runtime.Serialization; 5: using System.Threading; 6: using FakeChannelExample.Models; 7:   8: namespace FakeChannelExample.Tests 9: { 10: public class FakeHttpChannel<T> : HttpClientChannel 11: { 12: private T responseObject; 13:   14: public FakeHttpChannel(T responseObject) 15: { 16: this.responseObject = responseObject; 17: } 18:   19: protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken) 20: { 21: return new HttpResponseMessage() 22: { 23: RequestMessage = request, 24: Content = new StreamContent(this.GetContentStream()) 25: }; 26: } 27:   28: private Stream GetContentStream() 29: { 30: var serializer = new DataContractSerializer(typeof(T)); 31: Stream stream = new MemoryStream(); 32: serializer.WriteObject(stream, this.responseObject); 33: stream.Position = 0; 34: return stream; 35: } 36: } 37: } The HttpClientChannel provides a Send() method which you can override to return any HttpResponseMessage that you want. You can see I’m using the DataContractSerializer to serialize the object and write it to a stream. That’s all you need to do. In the example above, the only thing I’ve chosen to do is to provide a way to return different response objects. But there are many more features you could add to your own re-usable FakeHttpChannel. For example, you might want to provide the ability to add HTTP headers to the message. You might want to use a different serializer other than the DataContractSerializer. You might want to provide custom hypermedia in the response as well as just an object or set HTTP response codes. This list goes on. This is the just one example of the really cool features being added to the next version of WCF to enable various HTTP scenarios. The code sample for this post can be downloaded here.

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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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• first install for windows eight.....da beta

  - by raysmithequip

  The W8 preview is now installed and I am enjoying it.  I remember the learning curve of my first unix machine back in the eighties, this ain't that.It is normal for me to do the first os install with a keyboard and low end monitor...you never know what you'll encounter out in the field.  The OS took like a fish to water.  I used a low end INTEL motherboard dp55w I gathered on the cheap, an 1157 i5 from the used bin a pair of 6 gig ddr3 sticks, a rosewell 550 watt power supply a cheap used twenty buck sub 200g wd sata drive, a half working dvd burner and an asus fanless nvidia vid card, not a great one but Sub 50.00 on newey eggey...I did have to hunt the ms forums for a key and of course to activate the thing, if dos would of needed this outmoded ritual, we would still be on cpm and osborne would be a household name, of course little do people know that this ritual was common as far back as the seventies on att unix installs....not, but it was possible, I used to joke about when I ran a bbs, what hell would of been wrought had dos 3.2 machines been required to dial into my bbs to send fido mail to ms and wait for an acknowledgement.  All in all the thing was pushing a seven on the ms richter scale, not including the vid card, sadly it came in at just a tad over three....I wanted to evaluate it for a possible replacement on critical machines that in the past went down due to a vid card fan failure....you have no idea what a customer thinks when you show them a failed vid card fan..."you mean that little plastic piece of junk caused all this!!??!!!"...yea man.  Some production machines don't need any sort of vid, I will at least keep it on the maybe list for those, MTBF is a very important factor, some big box stores should put percentage of failure rate within 24 month estimates on the outside of the carton for sure.  And a warning that the power supplies are already at their limit.  Let's face it, today even 550w can be iffy.A few neat eye candy improvements over the earlier windows is nice, the metro screen is nice, anyone who has used a newer phone recently will intuitively drag their fingers across the screen....lot of good that was with no mouse or touch screen though.  Lucky me, I have been using windows since day one, I still have a copy of win 2.0 (and every other version) for no good reason.  Still the old ix collection of disks is much larger, recompiling any kernal is another silly ritual, same machine, different day, same recompile...argh. Rh is my all time fav, mandrake was always missing something, like it rewrote the init file or something, novell is ok as long as you stay on the beaten path and of course ubuntu normally recompiles with the same errors consistantly....makes life easy that way....no errors on windows eight, just a screen that did not match the installed hardware, natuarally I alt tabbed right out of it, then hit the flag key to find the start menu....no start button. I miss the start button already. Keyboard cowboy funnin and I was browsing the harddrive, nothing stunning there, I like that, means I can find stuff. Only I can't find what I want, the start button....the start menu is that first screen for touch tablets. No biggie for useruser, that is where they will want to be, I can see that. Admins won't want to be there, it is easy enough to get the control panel a bazzilion other ways though, just not the start button. (see a pattern here?). Personally, from the keyboard I find it fun to hit the carets along the location bar at the top of the explorer screen with tabs and arrows and choose SHOW ALL CONTROL PANEL ITEMS, or thereabouts. Bottom line, I love seven and I'll love eight even more!...very happy I did not have to follow the normal rule of thumb (a customer watching me build a system and asking questions said "oh I get it, so every piece you put in there is basically a hundred bucks, right?)...ok, sure, pretty much, more or less, well, ya dude.  It will be WAY past october till I get a real touch screen but I did pick up a pair of cheap tatungs so I can try the NEW main start screen, I parse a lot of folders and have a vision of how a pair of touch screens will be easier than landing a rover on mars.  Ok.  fine, they are way smallish, and I don't expect multitouch to work but we are talking a few percent of a new 21 inch viewsonic touch screen.  Will this OS be a game changer?  I don't know.  Bottom line with all the pads and droids in the world, it is more of a catch up move at first glance.  Not something ms is used to.  An app store?  I can see ms's motivation, the others have it.  I gather there will not be gadgets there, go ahead and see what ms did  to the once populated gadget page...go ahead, google gadgets and take a gander, used to hundreds of gadgets, they are already gone.  They replaced gadgets?  sort of, I'll drop that, it's a bit of a sore point for me.  More of interest was what happened when I downloaded stuff off codeplex and some other normal programs that I like, like orbitron, top o' my list!!...cardware it is...anyways, click on the exe, get a screen, normal for windows, this one indicated that I was not running a normal windows program and had a button for  exit the install, naw, I hit details, a hidden run program anyways came into view....great, my path to the normal windows has detected a program tha.....yea ok, acl is on, fine, moving along I got orbitron installed in record time and was tracking the iss on the newest Microsoft OS, beta of course, felt like the first time I setup bsd all those year ago...FUN!!...I suppose I gotta start to think about budgeting for the real os when it comes out in october, by then I should have a rasberry pi and be done with fedora remixed.  Of course that sounds like fun too!!  I would use this OS on a tablet or phone.  I don't like the idea of being hearded to an app store, don't like that on anything, we are americans and want real choices not marketed hype, lest you are younger with opm (other peoples money).   This os would be neat on a zune, but I suspect the zune is a gonner, I am rooting for microsoft, after all their default password is not admin anymore, nor alpine,  it's blank. Others force a password, my first fawn password was so long I could not even log into it with the password in front of me, who the heck uses %$# anyways, and if I was writing a brute force attack what the heck kinda impasse is that anyways at .00001 microseconds of a code execution cycle (just a non qualified number, not a real clock speed)....AI is where it will be before too long, MS is on that path, perhaps soon someone will sit down and write an app for the kinect that watches your eyes while you scan the new main start screen, clicking on the big E icon when you blink.....boy is that going to be fun!!!! sure. Blink,dammit,blink,dammit...... OPM no doubt.I like windows eight, we are moving forwards, better keep a close eye on ubuntu.  The real clinch comes when open source becomes paid source......don't blink, I already see plenty of very expensive 'ix apps, some even in app stores already.  more to come.......

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• The Presentation Isn't Over Until It's Over

  - by Phil Factor

  The senior corporate dignitaries settled into their seats looking important in a blue-suited sort of way. The lights dimmed as I strode out in front to give my presentation.  I had ten vital minutes to make my pitch.  I was about to dazzle the top management of a large software company who were considering the purchase of my software product. I would present them with a dazzling synthesis of diagrams, graphs, followed by  a live demonstration of my software projected from my laptop.  My preparation had been meticulous: It had to be: A year’s hard work was at stake, so I’d prepared it to perfection.  I stood up and took them all in, with a gaze of sublime confidence. Then the laptop expired. There are several possible alternative plans of action when this happens     A. Stare at the smoking laptop vacuously, flapping ones mouth slowly up and down     B. Stand frozen like a statue, locked in indecision between fright and flight.     C. Run out of the room, weeping     D. Pretend that this was all planned     E. Abandon the presentation in favour of a stilted and tedious dissertation about the software     F. Shake your fist at the sky, and curse the sense of humour of your preferred deity I started for a few seconds on plan B, normally referred to as the ‘Rabbit in the headlamps of the car’ technique. Suddenly, a little voice inside my head spoke. It spoke the famous inane words of Yogi Berra; ‘The game isn't over until it's over.’ ‘Too right’, I thought. What to do? I ran through the alternatives A-F inclusive in my mind but none appealed to me. I was completely unprepared for this. Nowadays, longevity has since taught me more than I wanted to know about the wacky sense of humour of fate, and I would have taken two laptops. I hadn’t, but decided to do the presentation anyway as planned. I started out ignoring the dead laptop, but pretending, instead that it was still working. The audience looked startled. They were expecting plan B to be succeeded by plan C, I suspect. They weren’t used to denial on this scale. After my introductory talk, which didn’t require any visuals, I came to the diagram that described the application I’d written.  I’d taken ages over it and it was hot stuff. Well, it would have been had it been projected onto the screen. It wasn’t. Before I describe what happened then, I must explain that I have thespian tendencies.  My  triumph as Professor Higgins in My Fair Lady at the local operatic society is now long forgotten, but I remember at the time of my finest performance, the moment that, glancing up over the vast audience of  moist-eyed faces at the during the poignant  scene between Eliza and Higgins at the end, I  realised that I had a talent that one day could possibly  be harnessed for commercial use I just talked about the diagram as if it was there, but throwing in some extra description. The audience nodded helpfully when I’d done enough. Emboldened, I began a sort of mime, well, more of a ballet, to represent each slide as I came to it. Heaven knows I’d done my preparation and, in my mind’s eye, I could see every detail, but I had to somehow project the reality of that vision to the audience, much the same way any actor playing Macbeth should do the ghost of Banquo.  My desperation gave me a manic energy. If you’ve ever demonstrated a windows application entirely by mime, gesture and florid description, you’ll understand the scale of the challenge, but then I had nothing to lose. With a brief sentence of description here and there, and arms flailing whilst outlining the size and shape of  graphs and diagrams, I used the many tricks of mime, gesture and body-language  learned from playing Captain Hook, or the Sheriff of Nottingham in pantomime. I set out determinedly on my desperate venture. There wasn’t time to do anything but focus on the challenge of the task: the world around me narrowed down to ten faces and my presentation: ten souls who had to be hypnotized into seeing a Windows application:  one that was slick, well organized and functional I don’t remember the details. Eight minutes of my life are gone completely. I was a thespian berserker.  I know however that I followed the basic plan of building the presentation in a carefully controlled crescendo until the dazzling finale where the results were displayed on-screen.  ‘And here you see the results, neatly formatted and grouped carefully to enhance the significance of the figures, together with running trend-graphs!’ I waved a mime to signify an animated  window-opening, and looked up, in my first pause, to gaze defiantly  at the audience.  It was a sight I’ll never forget. Ten pairs of eyes were gazing in rapt attention at the imaginary window, and several pairs of eyes were glancing at the imaginary graphs and figures.  I hadn’t had an audience like that since my starring role in  Beauty and the Beast.  At that moment, I realized that my desperate ploy might work. I sat down, slightly winded, when my ten minutes were up.  For the first and last time in my life, the audience of a  ‘PowerPoint’ presentation burst into spontaneous applause. ‘Any questions?’ ‘Yes,  Have you got an agent?’ Yes, in case you’re wondering, I got the deal. They bought the software product from me there and then. However, it was a life-changing experience for me and I have never ever again trusted technology as part of a presentation.  Even if things can’t go wrong, they’ll go wrong and they’ll kill the flow of what you’re presenting.  if you can’t do something without the techno-props, then you shouldn’t do it.  The greatest lesson of all is that great presentations require preparation and  ‘stage-presence’ rather than fancy graphics. They’re a great supporting aid, but they should never dominate to the point that you’re lost without them.

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• CodePlex Daily Summary for Monday, August 11, 2014

  CodePlex Daily Summary for Monday, August 11, 2014Popular ReleasesSpace Engineers Server Manager: SESM V1.15: V1.15 - Updated Quartz library - Correct a bug in the new mod managment - Added a warning if you have backup enabled on a server but no static map configuredAspose for Apache POI: Missing Features of Apache POI SS - v 1.2: Release contain the Missing Features in Apache POI SS SDK in comparison with Aspose.Cells What's New ? Following Examples: Create Pivot Charts Detect Merged Cells Sort Data Printing Workbooks Feedback and Suggestions Many more examples are available at Aspose Docs. Raise your queries and suggest more examples via Aspose Forums or via this social coding site.AngularGo (SPA Project Template): AngularGo.VS2013.vsix: First ReleaseTouchmote: Touchmote 1.0 beta 13: Changes Less GPU usage Works together with other Xbox 360 controls Bug fixesPublic Key Infrastructure PowerShell module: PowerShell PKI Module v3.0: Important: I would like to hear more about what you are thinking about the project? I appreciate that you like it (2000 downloads over past 6 months), but may be you have to say something? What do you dislike in the module? Maybe you would love to see some new functionality? Tell, what you think! Installation guide:Use default installation path to install this module for current user only. To install this module for all users — enable "Install for all users" check-box in installation UI ...Modern UI for WPF: Modern UI 1.0.6: The ModernUI assembly including a demo app demonstrating the various features of Modern UI for WPF. BREAKING CHANGE LinkGroup.GroupName renamed to GroupKey NEW FEATURES Improved rendering on high DPI screens, including support for per-monitor DPI awareness available in Windows 8.1 (see also Per-monitor DPI awareness) New ModernProgressRing control with 8 builtin styles New LinkCommands.NavigateLink routed command New Visual Studio project templates 'Modern UI WPF App' and 'Modern UI W...ClosedXML - The easy way to OpenXML: ClosedXML 0.74.0: Multiple thread safe improvements including AdjustToContents XLHelper XLColor_Static IntergerExtensions.ToStringLookup Exception now thrown when saving a workbook with no sheets, instead of creating a corrupt workbook Fix for hyperlinks with non-ASCII Characters Added basic workbook protection Fix for error thrown, when a spreadsheet contained comments and images Fix to Trim function Fix Invalid operation Exception thrown when the formula functions MAX, MIN, and AVG referenc...SEToolbox: SEToolbox 01.042.019 Release 1: Added RadioAntenna broadcast name to ship name detail. Added two additional columns for Asteroid material generation for Asteroid Fields. Added Mass and Block number columns to main display. Added Ellipsis to some columns on main display to reduce name confusion. Added correct SE version number in file when saving. Re-added in reattaching Motor when drag/dropping or importing ships (KeenSH have added RotorEntityId back in after removing it months ago). Added option to export and r...jQuery List DragSort: jQuery List DragSort 0.5.2: Fixed scrollContainer removing deprecated use of $.browser so should now work with latest version of jQuery. Added the ability to return false in dragEnd to revert sort order Project changes Added nuget package for dragsort https://www.nuget.org/packages/dragsort Converted repository from SVN to MercurialBraintree Client Library: Braintree 2.32.0: Allow credit card verification options to be passed outside of the nonce for PaymentMethod.create Allow billingaddress parameters and billingaddress_id to be passed outside of the nonce for PaymentMethod.create Add Subscriptions to paypal accounts Add PaymentMethod.update Add failonduplicatepaymentmethod option to PaymentMethod.create Add support for dispute webhooksThe Mario Kart 8 App: V1.0.2.1: First Codeplex release. WINDOWS INSTALLER ONLYAspose Java for Docx4j: Aspose.Words vs Docx4j - v 1.0: Release contain the Code Comparison for Features in Docx4j SDK and Aspose.Words What's New ?Following Examples: Accessing Document Properties Add Bookmarks Convert to Formats Delete Bookmarks Working with Comments Feedback and Suggestions Many more examples are available at Aspose Docs. Raise your queries and suggest more examples via Aspose Forums or via this social coding site.File System Security PowerShell Module: NTFSSecurity 2.4.1: Add-Access and Remove-Access now take multiple accoutsYourSqlDba: YourSqlDba 5.2.1.: This version improves alert message that comes a while after you install the script. First it says to get it from YourSqlDba.CodePlex.com If you don't want to update now, just-rerun the script from your installed version. To get actual version running just execute install.PrintVersionInfo. . You can go to source code / history and click on change set 72957 to see changes in the script.Manipulator: Manipulator: manipulatorXNB filetype plugin for Paint.NET: Paint.NET XNB plugin v0.4.0.0: CHANGELOG Reverted old incomplete changes. Updated library for compatibility with Paint .NET 4. Updated project to NET 4.5. Updated version to 0.4.0.0. INSTALLATION INSTRUCTIONS Extract the ZIP file to your Paint.NET\FileTypes folder.EdiFabric: Release 4.1: Changed MessageContextWix# (WixSharp) - managed interface for WiX: Release 1.0.0.0: Release 1.0.0.0 Custom UI Custom MSI Dialog Custom CLR Dialog External UIMath.NET Numerics: Math.NET Numerics v3.2.0: Linear Algebra: Vector.Map2 (map2 in F#), storage-optimized Linear Algebra: fix RemoveColumn/Row early index bound check (was not strict enough) Statistics: Entropy ~Jeff Mastry Interpolation: use Array.BinarySearch instead of local implementation ~Candy Chiu Resources: fix a corrupted exception message string Portable Build: support .Net 4.0 as well by using profile 328 instead of 344. .Net 3.5: F# extensions now support .Net 3.5 as well .Net 3.5: NuGet package now contains pro...babelua: 1.6.5.1: V1.6.5.1 - 2014.8.7New feature: Formatting code; Stability improvement: fix a bug that pop up error "System.Net.WebResponse EndGetResponse";New ProjectsDouDou: a little project.Dynamic MVC: Dynamically generate views from your model objects for a data centric MVC application.EasyDb - Simple Data Access: EasyDb is a simple library for data access that allows you to write less code.ExpressToAbroad: just go!!!!!Full Silverlight Web Video/Voice Conferencing: The Goal of this project is to provide complete Open Source (Voice/Video Chatting Client/Server) Modules Using SilverlightGaia: Gaia is an app for Windows plataform, Gaia is like Siri and Google Now or Betty but Gaia use only text commands.pxctest: pxctestSTACS: Career Management System for MIT by Team "STACS"StrongWorld: StrongWorld.WebSuiteXevas Tools: Xevas is a professional coders group of 'Nimbuzz'. We make all tools for worldwide users of nimbuzz at free of cost.????????: ????????????????: ???????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ????????????????: ????????????????: ???????????????: ???????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ???????????????: ???????????????: ??????????????: ??????????????: ??????????????: ????????????????: ????????????????: ???????????????: ???????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ???????????????: ???????????????: ??????????????: ??????????????: ??????????????: ???????????????: ???????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ???????????????: ???????????????: ??????????????: ??????????????: ??????????????: ???????????????: ????????????????: ???????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ???????????????: ???????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ???????????????: ???????????????: ??????????????: ??????????????: ??????????????: ??????????????: ????????????????: ????????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ??????????????: ???????????????: ???????????????: ??????????????: ??????????????: ??????????????: ????????????????: ?????????

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• Secure Your Wireless Router: 8 Things You Can Do Right Now

  - by Chris Hoffman

  A security researcher recently discovered a backdoor in many D-Link routers, allowing anyone to access the router without knowing the username or password. This isn’t the first router security issue and won’t be the last. To protect yourself, you should ensure that your router is configured securely. This is about more than just enabling Wi-Fi encryption and not hosting an open Wi-Fi network. Disable Remote Access Routers offer a web interface, allowing you to configure them through a browser. The router runs a web server and makes this web page available when you’re on the router’s local network. However, most routers offer a “remote access” feature that allows you to access this web interface from anywhere in the world. Even if you set a username and password, if you have a D-Link router affected by this vulnerability, anyone would be able to log in without any credentials. If you have remote access disabled, you’d be safe from people remotely accessing your router and tampering with it. To do this, open your router’s web interface and look for the “Remote Access,” “Remote Administration,” or “Remote Management” feature. Ensure it’s disabled — it should be disabled by default on most routers, but it’s good to check. Update the Firmware Like our operating systems, web browsers, and every other piece of software we use, router software isn’t perfect. The router’s firmware — essentially the software running on the router — may have security flaws. Router manufacturers may release firmware updates that fix such security holes, although they quickly discontinue support for most routers and move on to the next models. Unfortunately, most routers don’t have an auto-update feature like Windows and our web browsers do — you have to check your router manufacturer’s website for a firmware update and install it manually via the router’s web interface. Check to be sure your router has the latest available firmware installed. Change Default Login Credentials Many routers have default login credentials that are fairly obvious, such as the password “admin”. If someone gained access to your router’s web interface through some sort of vulnerability or just by logging onto your Wi-Fi network, it would be easy to log in and tamper with the router’s settings. To avoid this, change the router’s password to a non-default password that an attacker couldn’t easily guess. Some routers even allow you to change the username you use to log into your router. Lock Down Wi-Fi Access If someone gains access to your Wi-Fi network, they could attempt to tamper with your router — or just do other bad things like snoop on your local file shares or use your connection to downloaded copyrighted content and get you in trouble. Running an open Wi-Fi network can be dangerous. To prevent this, ensure your router’s Wi-Fi is secure. This is pretty simple: Set it to use WPA2 encryption and use a reasonably secure passphrase. Don’t use the weaker WEP encryption or set an obvious passphrase like “password”. Disable UPnP A variety of UPnP flaws have been found in consumer routers. Tens of millions of consumer routers respond to UPnP requests from the Internet, allowing attackers on the Internet to remotely configure your router. Flash applets in your browser could use UPnP to open ports, making your computer more vulnerable. UPnP is fairly insecure for a variety of reasons. To avoid UPnP-based problems, disable UPnP on your router via its web interface. If you use software that needs ports forwarded — such as a BitTorrent client, game server, or communications program — you’ll have to forward ports on your router without relying on UPnP. Log Out of the Router’s Web Interface When You’re Done Configuring It Cross site scripting (XSS) flaws have been found in some routers. A router with such an XSS flaw could be controlled by a malicious web page, allowing the web page to configure settings while you’re logged in. If your router is using its default username and password, it would be easy for the malicious web page to gain access. Even if you changed your router’s password, it would be theoretically possible for a website to use your logged-in session to access your router and modify its settings. To prevent this, just log out of your router when you’re done configuring it — if you can’t do that, you may want to clear your browser cookies. This isn’t something to be too paranoid about, but logging out of your router when you’re done using it is a quick and easy thing to do. Change the Router’s Local IP Address If you’re really paranoid, you may be able to change your router’s local IP address. For example, if its default address is 192.168.0.1, you could change it to 192.168.0.150. If the router itself were vulnerable and some sort of malicious script in your web browser attempted to exploit a cross site scripting vulnerability, accessing known-vulnerable routers at their local IP address and tampering with them, the attack would fail. This step isn’t completely necessary, especially since it wouldn’t protect against local attackers — if someone were on your network or software was running on your PC, they’d be able to determine your router’s IP address and connect to it. Install Third-Party Firmwares If you’re really worried about security, you could also install a third-party firmware such as DD-WRT or OpenWRT. You won’t find obscure back doors added by the router’s manufacturer in these alternative firmwares. Consumer routers are shaping up to be a perfect storm of security problems — they’re not automatically updated with new security patches, they’re connected directly to the Internet, manufacturers quickly stop supporting them, and many consumer routers seem to be full of bad code that leads to UPnP exploits and easy-to-exploit backdoors. It’s smart to take some basic precautions. Image Credit: Nuscreen on Flickr     

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• Online ALTER TABLE in MySQL 5.6

  - by Marko Mäkelä

  This is the low-level view of data dictionary language (DDL) operations in the InnoDB storage engine in MySQL 5.6. John Russell gave a more high-level view in his blog post April 2012 Labs Release – Online DDL Improvements. MySQL before the InnoDB Plugin Traditionally, the MySQL storage engine interface has taken a minimalistic approach to data definition language. The only natively supported operations were CREATE TABLE, DROP TABLE and RENAME TABLE. Consider the following example: CREATE TABLE t(a INT); INSERT INTO t VALUES (1),(2),(3); CREATE INDEX a ON t(a); DROP TABLE t; The CREATE INDEX statement would be executed roughly as follows: CREATE TABLE temp(a INT, INDEX(a)); INSERT INTO temp SELECT * FROM t; RENAME TABLE t TO temp2; RENAME TABLE temp TO t; DROP TABLE temp2; You could imagine that the database could crash when copying all rows from the original table to the new one. For example, it could run out of file space. Then, on restart, InnoDB would roll back the huge INSERT transaction. To fix things a little, a hack was added to ha_innobase::write_row for committing the transaction every 10,000 rows. Still, it was frustrating that even a simple DROP INDEX would make the table unavailable for modifications for a long time. Fast Index Creation in the InnoDB Plugin of MySQL 5.1 MySQL 5.1 introduced a new interface for CREATE INDEX and DROP INDEX. The old table-copying approach can still be forced by SET old_alter_table=0. This interface is used in MySQL 5.5 and in the InnoDB Plugin for MySQL 5.1. Apart from the ability to do a quick DROP INDEX, the main advantage is that InnoDB will execute a merge-sort algorithm before inserting the index records into each index that is being created. This should speed up the insert into the secondary index B-trees and potentially result in a better B-tree fill factor. The 5.1 ALTER TABLE interface was not perfect. For example, DROP FOREIGN KEY still invoked the table copy. Renaming columns could conflict with InnoDB foreign key constraints. Combining ADD KEY and DROP KEY in ALTER TABLE was problematic and not atomic inside the storage engine. The ALTER TABLE interface in MySQL 5.6 The ALTER TABLE storage engine interface was completely rewritten in MySQL 5.6. Instead of introducing a method call for every conceivable operation, MySQL 5.6 introduced a handful of methods, and data structures that keep track of the requested changes. In MySQL 5.6, online ALTER TABLE operation can be requested by specifying LOCK=NONE. Also LOCK=SHARED and LOCK=EXCLUSIVE are available. The old-style table copying can be requested by ALGORITHM=COPY. That one will require at least LOCK=SHARED. From the InnoDB point of view, anything that is possible with LOCK=EXCLUSIVE is also possible with LOCK=SHARED. Most ALGORITHM=INPLACE operations inside InnoDB can be executed online (LOCK=NONE). InnoDB will always require an exclusive table lock in two phases of the operation. The execution phases are tied to a number of methods: handler::check_if_supported_inplace_alter Checks if the storage engine can perform all requested operations, and if so, what kind of locking is needed. handler::prepare_inplace_alter_table InnoDB uses this method to set up the data dictionary cache for upcoming CREATE INDEX operation. We need stubs for the new indexes, so that we can keep track of changes to the table during online index creation. Also, crash recovery would drop any indexes that were incomplete at the time of the crash. handler::inplace_alter_table In InnoDB, this method is used for creating secondary indexes or for rebuilding the table. This is the ‘main’ phase that can be executed online (with concurrent writes to the table). handler::commit_inplace_alter_table This is where the operation is committed or rolled back. Here, InnoDB would drop any indexes, rename any columns, drop or add foreign keys, and finalize a table rebuild or index creation. It would also discard any logs that were set up for online index creation or table rebuild. The prepare and commit phases require an exclusive lock, blocking all access to the table. If MySQL times out while upgrading the table meta-data lock for the commit phase, it will roll back the ALTER TABLE operation. In MySQL 5.6, data definition language operations are still not fully atomic, because the data dictionary is split. Part of it is inside InnoDB data dictionary tables. Part of the information is only available in the *.frm file, which is not covered by any crash recovery log. But, there is a single commit phase inside the storage engine. Online Secondary Index Creation It may occur that an index needs to be created on a new column to speed up queries. But, it may be unacceptable to block modifications on the table while creating the index. It turns out that it is conceptually not so hard to support online index creation. All we need is some more execution phases: Set up a stub for the index, for logging changes. Scan the table for index records. Sort the index records. Bulk load the index records. Apply the logged changes. Replace the stub with the actual index. Threads that modify the table will log the operations to the logs of each index that is being created. Errors, such as log overflow or uniqueness violations, will only be flagged by the ALTER TABLE thread. The log is conceptually similar to the InnoDB change buffer. The bulk load of index records will bypass record locking. We still generate redo log for writing the index pages. It would suffice to log page allocations only, and to flush the index pages from the buffer pool to the file system upon completion. Native ALTER TABLE Starting with MySQL 5.6, InnoDB supports most ALTER TABLE operations natively. The notable exceptions are changes to the column type, ADD FOREIGN KEY except when foreign_key_checks=0, and changes to tables that contain FULLTEXT indexes. The keyword ALGORITHM=INPLACE is somewhat misleading, because certain operations cannot be performed in-place. For example, changing the ROW_FORMAT of a table requires a rebuild. Online operation (LOCK=NONE) is not allowed in the following cases: when adding an AUTO_INCREMENT column, when the table contains FULLTEXT indexes or a hidden FTS_DOC_ID column, or when there are FOREIGN KEY constraints referring to the table, with ON…CASCADE or ON…SET NULL option. The FOREIGN KEY limitations are needed, because MySQL does not acquire meta-data locks on the child or parent tables when executing SQL statements. Theoretically, InnoDB could support operations like ADD COLUMN and DROP COLUMN in-place, by lazily converting the table to a newer format. This would require that the data dictionary keep multiple versions of the table definition. For simplicity, we will copy the entire table, even for DROP COLUMN. The bulk copying of the table will bypass record locking and undo logging. For facilitating online operation, a temporary log will be associated with the clustered index of table. Threads that modify the table will also write the changes to the log. When altering the table, we skip all records that have been marked for deletion. In this way, we can simply discard any undo log records that were not yet purged from the original table. Off-page columns, or BLOBs, are an important consideration. We suspend the purge of delete-marked records if it would free any off-page columns from the old table. This is because the BLOBs can be needed when applying changes from the log. We have special logging for handling the ROLLBACK of an INSERT that inserted new off-page columns. This is because the columns will be freed at rollback.

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• SharePoint logging to a list

  - by Norgean

  I recently worked in an environment with several servers. Locating the correct SharePoint log file for error messages, or development trace calls, is cumbersome. And once the solution hit the cloud, it got even worse, as we had no access to the log files at all. Obviously we are not the only ones with this problem, and the current trend seems to be to log to a list. This had become an off-hour project, so rather than do the sensible thing and find a ready-made solution, I decided to do it the hard way. So! Fire up Visual Studio, create yet another empty SharePoint solution, and start to think of some requirements. Easy on/offI want to be able to turn list-logging on and off.Easy loggingFor me, this means being able to use string.Format.Easy filteringLet's have the possibility to add some filtering columns; category and severity, where severity can be "verbose", "warning" or "error". Easy on/off Well, that's easy. Create a new web feature. Add an event receiver, and create the list on activation of the feature. Tear the list down on de-activation. I chose not to create a new content type; I did not feel that it would give me anything extra. I based the list on the generic list - I think a better choice would have been the announcement type. Approximately: public void CreateLog(SPWeb web)         {             var list = web.Lists.TryGetList(LogListName);             if (list == null)             {                 var listGuid = web.Lists.Add(LogListName, "Logging for the masses", SPListTemplateType.GenericList);                 list = web.Lists[listGuid];                 list.Title = LogListTitle;                 list.Update();                 list.Fields.Add(Category, SPFieldType.Text, false);                 var stringColl = new StringCollection();                 stringColl.AddRange(new[]{Error, Information, Verbose});                 list.Fields.Add(Severity, SPFieldType.Choice, true, false, stringColl);                 ModifyDefaultView(list);             }         }Should be self explanatory, but: only create the list if it does not already exist (d'oh). Best practice: create it with a Url-friendly name, and, if necessary, give it a better title. ...because otherwise you'll have to look for a list with a name like "Simple_x0020_Log". I've added a couple of fields; a field for category, and a 'severity'. Both to make it easier to find relevant log messages. Notice that I don't have to call list.Update() after adding the fields - this would cause a nasty error (something along the lines of "List locked by another user"). The function for deleting the log is exactly as onerous as you'd expect:         public void DeleteLog(SPWeb web)         {             var list = web.Lists.TryGetList(LogListTitle);             if (list != null)             {                 list.Delete();             }         } So! "All" that remains is to log. Also known as adding items to a list. Lots of different methods with different signatures end up calling the same function. For example, LogVerbose(web, message) calls LogVerbose(web, null, message) which again calls another method which calls: private static void Log(SPWeb web, string category, string severity, string textformat, params object[] texts)         {             if (web != null)             {                 var list = web.Lists.TryGetList(LogListTitle);                 if (list != null)                 {                     var item = list.AddItem(); // NOTE! NOT list.Items.Add… just don't, mkay?                     var text = string.Format(textformat, texts);                     if (text.Length > 255) // because the title field only holds so many chars. Sigh.                         text = text.Substring(0, 254);                     item[SPBuiltInFieldId.Title] = text;                     item[Degree] = severity;                     item[Category] = category;                     item.Update();                 }             } // omitted: Also log to SharePoint log.         } By adding a params parameter I can call it as if I was doing a Console.WriteLine: LogVerbose(web, "demo", "{0} {1}{2}", "hello", "world", '!'); Ok, that was a silly example, a better one might be: LogError(web, LogCategory, "Exception caught when updating {0}. exception: {1}", listItem.Title, ex); For performance reasons I use list.AddItem rather than list.Items.Add. For completeness' sake, let us include the "ModifyDefaultView" function that I deliberately skipped earlier.         private void ModifyDefaultView(SPList list)         {             // Add fields to default view             var defaultView = list.DefaultView;             var exists = defaultView.ViewFields.Cast<string>().Any(field => String.CompareOrdinal(field, Severity) == 0);               if (!exists)             {                 var field = list.Fields.GetFieldByInternalName(Severity);                 if (field != null)                     defaultView.ViewFields.Add(field);                 field = list.Fields.GetFieldByInternalName(Category);                 if (field != null)                     defaultView.ViewFields.Add(field);                 defaultView.Update();                   var sortDoc = new XmlDocument();                 sortDoc.LoadXml(string.Format("<Query>{0}</Query>", defaultView.Query));                 var orderBy = (XmlElement) sortDoc.SelectSingleNode("//OrderBy");                 if (orderBy != null && sortDoc.DocumentElement != null)                     sortDoc.DocumentElement.RemoveChild(orderBy);                 orderBy = sortDoc.CreateElement("OrderBy");                 sortDoc.DocumentElement.AppendChild(orderBy);                 field = list.Fields[SPBuiltInFieldId.Modified];                 var fieldRef = sortDoc.CreateElement("FieldRef");                 fieldRef.SetAttribute("Name", field.InternalName);                 fieldRef.SetAttribute("Ascending", "FALSE");                 orderBy.AppendChild(fieldRef);                   fieldRef = sortDoc.CreateElement("FieldRef");                 field = list.Fields[SPBuiltInFieldId.ID];                 fieldRef.SetAttribute("Name", field.InternalName);                 fieldRef.SetAttribute("Ascending", "FALSE");                 orderBy.AppendChild(fieldRef);                 defaultView.Query = sortDoc.DocumentElement.InnerXml;                 //defaultView.Query = "<OrderBy><FieldRef Name='Modified' Ascending='FALSE' /><FieldRef Name='ID' Ascending='FALSE' /></OrderBy>";                 defaultView.Update();             }         } First two lines are easy - see if the default view includes the "Severity" column. If it does - quit; our job here is done.Adding "severity" and "Category" to the view is not exactly rocket science. But then? Then we build the sort order query. Through XML. The lines are numerous, but boring. All to achieve the CAML query which is commented out. The major benefit of using the dom to build XML, is that you may get compile time errors for spelling mistakes. I say 'may', because although the compiler will not let you forget to close a tag, it will cheerfully let you spell "Name" as "Naem". Whichever you prefer, at the end of the day the view will sort by modified date and ID, both descending. I added the ID as there may be several items with the same time stamp. So! Simple logging to a list, with sensible a view, and with normal functionality for creating your own filterings. I should probably have added some more views in code, ready filtered for "only errors", "errors and warnings" etc. And it would be nice to block verbose logging completely, but I'm not happy with the alternatives. (yetanotherfeature or an admin page seem like overkill - perhaps just removing it as one of the choices, and not log if it isn't there?) Before you comment - yes, try-catches have been removed for clarity. There is nothing worse than having a logging function that breaks your site!

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• git post-receive hook throws "command not found" error but seems to run properly and no errors when run manually

  - by Ben

  I have a post-receive hook that runs on a central git repository set up with gitolite to trigger a git pull on a staging server. It seems to work properly, but throws a "command not found" error when it is run. I am trying to track down the source of the error, but have not had any luck. Running the same commands manually does not produce an error. The error changes depending on what was done in the commit that is being pushed to the central repository. For instance, if 'git rm ' was committed and pushed to the central repo the error message will be "remote: hooks/post-receive: line 16: Removed: command not found" and if 'git add ' was committed and pushed to the central repo the error message will be "remote: hooks/post-receive: line 16: Merge: command not found". In either case the 'git pull' run on the staging server works correctly despite the error message. Here is the post-receive script: #!/bin/bash # # This script is triggered by a push to the local git repository. It will # ssh into a remote server and perform a git pull. # # The SSH_USER must be able to log into the remote server with a # passphrase-less SSH key *AND* be able to do a git pull without a passphrase. # # The command to actually perform the pull request on the remost server comes # from the ~/.ssh/authorized_keys file on the REMOTE_HOST and is triggered # by the ssh login. SSH_USER="remoteuser" REMOTE_HOST="staging.server.com" `ssh $SSH_USER@$REMOTE_HOST` # This is line 16 echo "Done!" The command that does the git pull on the staging server is in the ssh user's ~/.ssh/authorized_keys file and is: command="cd /var/www/staging_site; git pull",no-port-forwarding,no-X11-forwarding,no-agent-forwarding, ssh-rsa AAAAB3NzaC1yc2EAAAABIwAA... (the rest of the public key) This is the actual output from removing a file from my local repo, committing it locally, and pushing it to the central git repo: ben@tamarack:~/thejibe/testing/web$ git rm ./testing rm 'testing' ben@tamarack:~/thejibe/testing/web$ git commit -a -m "Remove testing file" [master bb96e13] Remove testing file 1 files changed, 0 insertions(+), 5 deletions(-) delete mode 100644 testing ben@tamarack:~/thejibe/testing/web$ git push Counting objects: 3, done. Delta compression using up to 2 threads. Compressing objects: 100% (2/2), done. Writing objects: 100% (2/2), 221 bytes, done. Total 2 (delta 1), reused 0 (delta 0) remote: From [email protected]:testing remote: aa72ad9..bb96e13 master -> origin/master remote: hooks/post-receive: line 16: Removed: command not found # The error msg remote: Done! To [email protected]:testing aa72ad9..bb96e13 master -> master ben@tamarack:~/thejibe/testing/web$ As you can see the post-receive script gets to the echo "Done!" line and when I look on the staging server the git pull has been successfully run, but there's still that nagging error message. Any suggestions on where to look for the source of the error message would be greatly appreciated. I'm tempted to redirect stderr to /dev/null but would prefer to know what the problem is.

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• git post-receive hook throws "command not found" error but seems to run properly and no errors when run manually

  - by Ben

  I have a post-receive hook that runs on a central git repository set up with gitolite to trigger a git pull on a staging server. It seems to work properly, but throws a "command not found" error when it is run. I am trying to track down the source of the error, but have not had any luck. Running the same commands manually does not produce an error. The error changes depending on what was done in the commit that is being pushed to the central repository. For instance, if 'git rm ' was committed and pushed to the central repo the error message will be "remote: hooks/post-receive: line 16: Removed: command not found" and if 'git add ' was committed and pushed to the central repo the error message will be "remote: hooks/post-receive: line 16: Merge: command not found". In either case the 'git pull' run on the staging server works correctly despite the error message. Here is the post-receive script: #!/bin/bash # # This script is triggered by a push to the local git repository. It will # ssh into a remote server and perform a git pull. # # The SSH_USER must be able to log into the remote server with a # passphrase-less SSH key *AND* be able to do a git pull without a passphrase. # # The command to actually perform the pull request on the remost server comes # from the ~/.ssh/authorized_keys file on the REMOTE_HOST and is triggered # by the ssh login. SSH_USER="remoteuser" REMOTE_HOST="staging.server.com" `ssh $SSH_USER@$REMOTE_HOST` # This is line 16 echo "Done!" The command that does the git pull on the staging server is in the ssh user's ~/.ssh/authorized_keys file and is: command="cd /var/www/staging_site; git pull",no-port-forwarding,no-X11-forwarding,no-agent-forwarding, ssh-rsa AAAAB3NzaC1yc2EAAAABIwAA... (the rest of the public key) This is the actual output from removing a file from my local repo, committing it locally, and pushing it to the central git repo: ben@tamarack:~/thejibe/testing/web$ git rm ./testing rm 'testing' ben@tamarack:~/thejibe/testing/web$ git commit -a -m "Remove testing file" [master bb96e13] Remove testing file 1 files changed, 0 insertions(+), 5 deletions(-) delete mode 100644 testing ben@tamarack:~/thejibe/testing/web$ git push Counting objects: 3, done. Delta compression using up to 2 threads. Compressing objects: 100% (2/2), done. Writing objects: 100% (2/2), 221 bytes, done. Total 2 (delta 1), reused 0 (delta 0) remote: From [email protected]:testing remote: aa72ad9..bb96e13 master -> origin/master remote: hooks/post-receive: line 16: Removed: command not found # The error msg remote: Done! To [email protected]:testing aa72ad9..bb96e13 master -> master ben@tamarack:~/thejibe/testing/web$ As you can see the post-receive script gets to the echo "Done!" line and when I look on the staging server the git pull has been successfully run, but there's still that nagging error message. Any suggestions on where to look for the source of the error message would be greatly appreciated. I'm tempted to redirect stderr to /dev/null but would prefer to know what the problem is.

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• How to correctly partition usb flash drive and which filesystem to choose considering wear leveling?

  - by random1

  Two problems. First one: how to partition the flash drive? I shouldn't need to do this, but I'm no longer sure if my partition is properly aligned since I was forced to delete and create a new partition table after gparted complained when I tried to format the drive from FAT to ext4. The naive answer would be to say "just use default and everything is going to be alright". However if you read the following links you'll know things are not that simple: https://lwn.net/Articles/428584/ and http://linux-howto-guide.blogspot.com/2009/10/increase-usb-flash-drive-write-speed.html Then there is also the issue of cylinders, heads and sectors. Currently I get this: $sfdisk -l -uM /dev/sdd Disk /dev/sdd: 30147 cylinders, 64 heads, 32 sectors/track Warning: The partition table looks like it was made for C/H/S=*/255/63 (instead of 30147/64/32). For this listing I'll assume that geometry. Units = mebibytes of 1048576 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End MiB #blocks Id System /dev/sdd1 1 30146 30146 30869504 83 Linux $fdisk -l /dev/sdd Disk /dev/sdd: 31.6 GB, 31611420672 bytes 255 heads, 63 sectors/track, 3843 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00010c28 So from my current understanding I should align partitions at 4 MiB (currently it's at 1 MiB). But I still don't know how to set the heads and sectors properly for my device. Second problem: file system. From the benchmarks I saw ext4 provides the best performance, however there is the issue of wear leveling. How can I know that my Transcend JetFlash 700's microcontroller provides for wear leveling? Or will I just be killing my drive faster? I've seen a lot of posts on the web saying don't worry the newer drives already take care of that. But I've never seen a single piece of backed evidence of that and at some point people start mixing SSD with USB flash drives technology. The safe option would be to go for ext2, however a serious of tests that I performed showed horrible performance!!! These values are from a real scenario and not some synthetic test: 42 files: 3,429,415,284 bytes copied to flash drive original fat32: 15.1 MiB/s ext4 after new partition table: 10.2 MiB/s ext2 after new partition table: 1.9 MiB/s Please read the links that I posted above before answering. I would also be interested in answers backed up with some references because a lot is said and re-said but then it lacks facts. Thank you for the help.

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• Bash-Scripting - Munin Plugin don't work

  - by FTV Admin

  i have written a munin-plugin to count the http-statuscodes of lighttpd. The script: #!/bin/bash ###################################### # Munin-Script: Lighttpd-Statuscodes # ###################################### ##Config # path to lighttpd access.log LIGHTTPD_ACCESS_LOG_PATH="/var/log/lighttpd/access.log" # rows to parse in logfile (higher value incrase time to run plugin. if value to low you may get bad counting) LOG_ROWS="200000" # #munin case $1 in autoconf) # check config AVAILABLE=`ls $LIGHTTPD_ACCESS_LOG_PATH` if [ "$AVAILABLE" = "$LIGHTTPD_ACCESS_LOG_PATH" ]; then echo "yes" else echo "No: "$AVAILABLE echo "Please check your config!" fi exit 0;; config) # graph config cat <<'EOM' graph_title Lighhtpd Statuscodes graph_vlabel http-statuscodes / min graph_category lighttpd 1xx.label 1xx 2xx.label 2xx 3xx.label 3xx 4xx.label 4xx 5xx.label 5xx EOM exit 0;; esac ## calculate AVAILABLE=`ls $LIGHTTPD_ACCESS_LOG_PATH` if [ "$AVAILABLE" = "$LIGHTTPD_ACCESS_LOG_PATH" ]; then TIME_NOW=`date` CODE_1xx="0" CODE_2xx="0" CODE_3xx="0" CODE_4xx="0" CODE_5xx="0" for i in 1 2 3 4 5; do TIME5=`date +%d/%b/%Y:%k:%M --date "$TIME_NOW -"$i"min"` CODE_1xx=$(( $CODE_1xx + `tail -n $LOG_ROWS $LIGHTTPD_ACCESS_LOG_PATH | grep "$TIME5" | grep 'HTTP/1.1" 1' | grep -c " "` )) CODE_2xx=$(( $CODE_2xx + `tail -n $LOG_ROWS $LIGHTTPD_ACCESS_LOG_PATH | grep "$TIME5" | grep 'HTTP/1.1" 2' | grep -c " "` )) CODE_3xx=$(( $CODE_3xx + `tail -n $LOG_ROWS $LIGHTTPD_ACCESS_LOG_PATH | grep "$TIME5" | grep 'HTTP/1.1" 3' | grep -c " "` )) CODE_4xx=$(( $CODE_4xx + `tail -n $LOG_ROWS $LIGHTTPD_ACCESS_LOG_PATH | grep "$TIME5" | grep 'HTTP/1.1" 4' | grep -c " "` )) CODE_5xx=$(( $CODE_5xx + `tail -n $LOG_ROWS $LIGHTTPD_ACCESS_LOG_PATH | grep "$TIME5" | grep 'HTTP/1.1" 5' | grep -c " "` )) done CODE_1xx=$(( $CODE_1xx / 5 )) CODE_2xx=$(( $CODE_2xx / 5 )) CODE_3xx=$(( $CODE_3xx / 5 )) CODE_4xx=$(( $CODE_4xx / 5 )) CODE_5xx=$(( $CODE_5xx / 5 )) echo "1xx.value "$CODE_1xx echo "2xx.value "$CODE_2xx echo "3xx.value "$CODE_3xx echo "4xx.value "$CODE_4xx echo "5xx.value "$CODE_5xx else echo "1xx.value U" echo "2xx.value U" echo "3xx.value U" echo "4xx.value U" echo "5xx.value U" fi If i run the script on local machine it runs perfectly: root@server1 /etc/munin/plugins # ll lrwxrwxrwx 1 root root 45 2011-12-19 15:23 lighttpd_statuscodes -> /usr/share/munin/plugins/lighttpd_statuscodes* root@server1 /etc/munin/plugins # ./lighttpd_statuscodes autoconf yes root@server1 /etc/munin/plugins # ./lighttpd_statuscodes config graph_title Lighhtpd Statuscodes graph_vlabel http-statuscodes / min graph_category lighttpd 1xx.label 1xx 2xx.label 2xx 3xx.label 3xx 4xx.label 4xx 5xx.label 5xx root@server1 /etc/munin/plugins #./lighttpd_statuscodes 1xx.value 0 2xx.value 5834 3xx.value 1892 4xx.value 0 5xx.value 0 But Munin shows no graph: http://s1.directupload.net/images/111219/3psgq3vb.jpg I have tested the Plugin from munin-server via telnet: root@munin-server /etc/munin/plugins/ # telnet 123.123.123.123 4949 Trying 123.123.123.123... Connected to 123.123.123.123. Escape character is '^]'. # munin node at server1.cluster1 fetch lighttpd_statuscodes 1xx.value U 2xx.value U 3xx.value U 4xx.value U 5xx.value U . Connection closed by foreign host. You can see in the script that value = U only printed, when the script can't check the lighttpd's access.log. But why can't script do it, when running via munin, and when running on local machine all is ok? Is there a bug in my bash-script? I have no Idea. Thanks for helping!

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• Understanding packet flows over RVI

  - by choco-loo

  I'm trying to get a full grasp of firewall filters and how to apply them on a Juniper EX4200 switch - to be able to block ports, police traffic and shape traffic. The network architecture is as follows internet >-< vlan4000 >-< vlan43 vlan4000 is a public "routed" block (where all the IPs are routed to and the internet gw is) vlan43 is a vlan with public IPs with devices (servers) attached There are static routes and RVI's on the EX4200 to send all traffic via vlan4000's gateway to reach the internet. I've set up filters on both input and output of the respective RVI's and VLAN's - with simple counters, to measure traffic flow from a server inside of vlan43 and a server on the internet. Using a combination of iperf for UDP and TCP tests and fping for ICMP tests - I observed the following, icmp vlan43>internet internet>vlan43 unit4000-counter-in 0 0 unit4000-counter-out 0 0 unit43-counter-in 100 100 unit43-counter-out 0 0 vlan4000-counter-in 6 4 vlan4000-counter-out 107 104 vlan43-counter-in 101 100 vlan43-counter-out 100 100 tcp vlan43>internet internet>vlan43 unit4000-counter-in 0 0 unit4000-counter-out 0 0 unit43-counter-in 73535 38480 unit43-counter-out 0 0 vlan4000-counter-in 7 8 vlan4000-counter-out 73543 38489 vlan43-counter-in 73535 38481 vlan43-counter-out 38938 75880 udp vlan43>internet internet>vlan43 unit4000-counter-in 0 0 unit4000-counter-out 0 0 unit43-counter-in 81410 1 unit43-counter-out 0 0 vlan4000-counter-in 18 7 vlan4000-counter-out 81429 8 vlan43-counter-in 81411 1 vlan43-counter-out 1 85472 My key goals are to set up a few filters and policers, as there will be many more VLANs - that all need protecting from each other and the internet. Then globally limit/police all outbound traffic to the internet Block inbound ports to vlan43 (eg. 22) Limit outbound traffic from vlan43 (to the internet) Limit outbound traffic from vlan43 (to other vlans) Limit outbound traffic from vlan4000 (to the internet from all vlans) Route traffic from vlans via specific routing instances (FBF) The question What I want to understand is why there isn't ever any activity on unit4000 or vlan4000 inbound or outbound counter - is this because there isn't a device on this VLAN - and that the traffic is only traversing it? And with regards to the TCP test - why is there twice as many packets on unit43-counter-in, vlan4000-counter-out and vlan43-counter-in - is this counting both the inbound and outbound traffic?

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• opening adobe reader results in infinite explorer.exe process creation loop

  - by irrational John

  First, apologies if the answer to this is only a Google away. I tried, honest I did. But I wasn't able to find anything about this problem posted elsewhere. I'm using Adobe Reader v9.3.2 in Windows 7 Home Premium 64-bit. If you want more system details, then just request them. What happens is that when I attempt to open a PDF by clicking "Open" on it then (1) adobe reader never opens and (2) the explorer.exe program is (apparently) recursively opened. I base this on opening the Task Manager and seeing a long list of explorer.exe processes under the "Processes" tab. Usually there is only one. When I recreate this problem, the list of explorer.exe processes are at least a page or two long. (Too many to bother counting). I "correct" this problem by logging off and then logging back on. This kills all the explorer.exe tasks. Unfortunately I don't know another way to terminate them all. Now here's the curious part. This only happens when I attempt to "Open" a PDF file. If instead I use the context menu (right mouse click on the PDF) and select "Open with" and "Adobe Reader 9.3" then Adobe Reader opens the file with no problem. It seems that there is something wrong with the setting for the default open action for PDF files. However, I have been unable to fix this by changing the Windows setting. Here is what I have tried. When I open Control Panel > All Control Panel Items > Default Programs > Set Associations I do not find an entry for file type .pdf. There are only entries for .pdfxml and .pdx. When use "Open with" on a PDF file and select "Choose default program", the check box for "Always use the selected program to open this kind of file" is disabled (greyed out). I have uninstalled and reinstalled Adobe Reader but the problem persists. While obviously no lives are at stake here, this problem is annoying the frickin' heck out of me. If I forget and recreate this bug then I have to stop everything I'm doing to stop it. Any suggestions on how I might go about fixing this?

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• How to setup GIT repo on server with need for working dir (non- bare)

  - by OrangeTux

  I want to have configurate a GIT repo for a website. Multiple users will have a clone of the repo on their local machine and on the end of each day they push their work to the server. I can setup a bare repo, but I want a working dir/non-bare repository. The idea is that the working dir of the repository will the root folder for the website. At the end of each day all changes will be visible directly. But I can't find a way to do this. Initializing the server repo with git init gives the following error when a client is trying to push some files: git push origin master [email protected]'s password: Counting objects: 3, done. Writing objects: 100% (3/3), 227 bytes, done. Total 3 (delta 0), reused 0 (delta 0) remote: error: refusing to update checked out branch: refs/heads/master remote: error: By default, updating the current branch in a non-bare repository remote: error: is denied, because it will make the index and work tree inconsistent remote: error: with what you pushed, and will require 'git reset --hard' to match remote: error: the work tree to HEAD. remote: error: remote: error: You can set 'receive.denyCurrentBranch' configuration variable to remote: error: 'ignore' or 'warn' in the remote repository to allow pushing into remote: error: its current branch; however, this is not recommended unless you remote: error: arranged to update its work tree to match what you pushed in some remote: error: other way. remote: error: remote: error: To squelch this message and still keep the default behaviour, set remote: error: 'receive.denyCurrentBranch' configuration variable to 'refuse'. To ssh://[email protected]/home/orangetux/www/ ! [remote rejected] master -> master (branch is currently checked out) error: failed to push some refs to 'ssh://[email protected]/home/orangetux/www/' So I'm wondering if this the right way to setup a GIT repo for a website? If so, how do I have to do this? If not, what is a better way to setup a GIT repo for the development of a website? EDIT you can't push to a non-bare repository Oke, clear. But whats the way to solve my problem? Create a bare repository on the server and have a clone of this repo on the same server in the htdocs folder? This looks a bit clumsy to me. To see the result of a commit I've to clone the repository each time.

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• c# Truncate HTML safely for article summary

  - by WickedW

  Hi All, Does anyone have a c# variation of this? This is so I can take some html and display it without breaking as a summary lead in to an article? http://stackoverflow.com/questions/1193500/php-truncate-html-ignoring-tags Save me from reinventing the wheel! Thank you very much ---------- edit ------------------ Sorry, new here, and your right, should have phrased the question better, heres a bit more info I wish to take a html string and truncate it to a set number of words (or even char length) so I can then show the start of it as a summary (which then leads to the main article). I wish to preserve the html so I can show the links etc in preview. The main issue I have to solve is the fact that we may well end up with unclosed html tags if we truncate in the middle of 1 or more tags! The idea I have for solution is to a) truncate the html to N words (words better but chars ok) first (be sure not to stop in the middle of a tag and truncate a require attribute) b) work through the opened html tags in this truncated string (maybe stick them on stack as I go?) c) then work through the closing tags and ensure they match the ones on stack as I pop them off? d) if any open tags left on stack after this, then write them to end of truncated string and html should be good to go!!!! -- edit 12112009 Here is what I have bumbled together so far as a unittest file in VS2008, this 'may' help someone in future My hack attempts based on Jan code are at top for char version + word version (DISCLAIMER: this is dirty rough code!! on my part) I assume working with 'well-formed' HTML in all cases (but not necessarily a full document with a root node as per XML version) Abels XML version is at bottom, but not yet got round to fully getting tests to run on this yet (plus need to understand the code) ... I will update when I get chance to refine having trouble with posting code? is there no upload facility on stack? Thanks for all comments :) using System; using System.Collections.Generic; using System.Text.RegularExpressions; using System.Xml; using System.Xml.XPath; using Microsoft.VisualStudio.TestTools.UnitTesting; namespace PINET40TestProject { [TestClass] public class UtilityUnitTest { public static string TruncateHTMLSafeishChar(string text, int charCount) { bool inTag = false; int cntr = 0; int cntrContent = 0; // loop through html, counting only viewable content foreach (Char c in text) { if (cntrContent == charCount) break; cntr++; if (c == '<') { inTag = true; continue; } if (c == '>') { inTag = false; continue; } if (!inTag) cntrContent++; } string substr = text.Substring(0, cntr); //search for nonclosed tags MatchCollection openedTags = new Regex("<[^/](.|\n)*?>").Matches(substr); MatchCollection closedTags = new Regex("<[/](.|\n)*?>").Matches(substr); // create stack Stack<string> opentagsStack = new Stack<string>(); Stack<string> closedtagsStack = new Stack<string>(); // to be honest, this seemed like a good idea then I got lost along the way // so logic is probably hanging by a thread!! foreach (Match tag in openedTags) { string openedtag = tag.Value.Substring(1, tag.Value.Length - 2); // strip any attributes, sure we can use regex for this! if (openedtag.IndexOf(" ") >= 0) { openedtag = openedtag.Substring(0, openedtag.IndexOf(" ")); } // ignore brs as self-closed if (openedtag.Trim() != "br") { opentagsStack.Push(openedtag); } } foreach (Match tag in closedTags) { string closedtag = tag.Value.Substring(2, tag.Value.Length - 3); closedtagsStack.Push(closedtag); } if (closedtagsStack.Count < opentagsStack.Count) { while (opentagsStack.Count > 0) { string tagstr = opentagsStack.Pop(); if (closedtagsStack.Count == 0 || tagstr != closedtagsStack.Peek()) { substr += "</" + tagstr + ">"; } else { closedtagsStack.Pop(); } } } return substr; } public static string TruncateHTMLSafeishWord(string text, int wordCount) { bool inTag = false; int cntr = 0; int cntrWords = 0; Char lastc = ' '; // loop through html, counting only viewable content foreach (Char c in text) { if (cntrWords == wordCount) break; cntr++; if (c == '<') { inTag = true; continue; } if (c == '>') { inTag = false; continue; } if (!inTag) { // do not count double spaces, and a space not in a tag counts as a word if (c == 32 && lastc != 32) cntrWords++; } } string substr = text.Substring(0, cntr) + " ..."; //search for nonclosed tags MatchCollection openedTags = new Regex("<[^/](.|\n)*?>").Matches(substr); MatchCollection closedTags = new Regex("<[/](.|\n)*?>").Matches(substr); // create stack Stack<string> opentagsStack = new Stack<string>(); Stack<string> closedtagsStack = new Stack<string>(); foreach (Match tag in openedTags) { string openedtag = tag.Value.Substring(1, tag.Value.Length - 2); // strip any attributes, sure we can use regex for this! if (openedtag.IndexOf(" ") >= 0) { openedtag = openedtag.Substring(0, openedtag.IndexOf(" ")); } // ignore brs as self-closed if (openedtag.Trim() != "br") { opentagsStack.Push(openedtag); } } foreach (Match tag in closedTags) { string closedtag = tag.Value.Substring(2, tag.Value.Length - 3); closedtagsStack.Push(closedtag); } if (closedtagsStack.Count < opentagsStack.Count) { while (opentagsStack.Count > 0) { string tagstr = opentagsStack.Pop(); if (closedtagsStack.Count == 0 || tagstr != closedtagsStack.Peek()) { substr += "</" + tagstr + ">"; } else { closedtagsStack.Pop(); } } } return substr; } public static string TruncateHTMLSafeishCharXML(string text, int charCount) { // your data, probably comes from somewhere, or as params to a methodint XmlDocument xml = new XmlDocument(); xml.LoadXml(text); // create a navigator, this is our primary tool XPathNavigator navigator = xml.CreateNavigator(); XPathNavigator breakPoint = null; // find the text node we need: while (navigator.MoveToFollowing(XPathNodeType.Text)) { string lastText = navigator.Value.Substring(0, Math.Min(charCount, navigator.Value.Length)); charCount -= navigator.Value.Length; if (charCount <= 0) { // truncate the last text. Here goes your "search word boundary" code: navigator.SetValue(lastText); breakPoint = navigator.Clone(); break; } } // first remove text nodes, because Microsoft unfortunately merges them without asking while (navigator.MoveToFollowing(XPathNodeType.Text)) { if (navigator.ComparePosition(breakPoint) == XmlNodeOrder.After) { navigator.DeleteSelf(); } } // moves to parent, then move the rest navigator.MoveTo(breakPoint); while (navigator.MoveToFollowing(XPathNodeType.Element)) { if (navigator.ComparePosition(breakPoint) == XmlNodeOrder.After) { navigator.DeleteSelf(); } } // moves to parent // then remove *all* empty nodes to clean up (not necessary): // TODO, add empty elements like <br />, <img /> as exclusion navigator.MoveToRoot(); while (navigator.MoveToFollowing(XPathNodeType.Element)) { while (!navigator.HasChildren && (navigator.Value ?? "").Trim() == "") { navigator.DeleteSelf(); } } // moves to parent navigator.MoveToRoot(); return navigator.InnerXml; } [TestMethod] public void TestTruncateHTMLSafeish() { // Case where we just make it to start of HREF (so effectively an empty link) // 'simple' nested none attributed tags Assert.AreEqual(@"<h1>1234</h1><b><i>56789</i>012</b>", TruncateHTMLSafeishChar( @"<h1>1234</h1><b><i>56789</i>012345</b>", 12)); // In middle of a! Assert.AreEqual(@"<h1>1234</h1><a href=""testurl""><b>567</b></a>", TruncateHTMLSafeishChar( @"<h1>1234</h1><a href=""testurl""><b>5678</b></a><i><strong>some italic nested in string</strong></i>", 7)); // more Assert.AreEqual(@"<div><b><i><strong>1</strong></i></b></div>", TruncateHTMLSafeishChar( @"<div><b><i><strong>12</strong></i></b></div>", 1)); // br Assert.AreEqual(@"<h1>1 3 5</h1><br />6", TruncateHTMLSafeishChar( @"<h1>1 3 5</h1><br />678<br />", 6)); } [TestMethod] public void TestTruncateHTMLSafeishWord() { // zero case Assert.AreEqual(@" ...", TruncateHTMLSafeishWord( @"", 5)); // 'simple' nested none attributed tags Assert.AreEqual(@"<h1>one two <br /></h1><b><i>three ...</i></b>", TruncateHTMLSafeishWord( @"<h1>one two <br /></h1><b><i>three </i>four</b>", 3), "we have added ' ...' to end of summary"); // In middle of a! Assert.AreEqual(@"<h1>one two three </h1><a href=""testurl""><b class=""mrclass"">four ...</b></a>", TruncateHTMLSafeishWord( @"<h1>one two three </h1><a href=""testurl""><b class=""mrclass"">four five </b></a><i><strong>some italic nested in string</strong></i>", 4)); // start of h1 Assert.AreEqual(@"<h1>one two three ...</h1>", TruncateHTMLSafeishWord( @"<h1>one two three </h1><a href=""testurl""><b>four five </b></a><i><strong>some italic nested in string</strong></i>", 3)); // more than words available Assert.AreEqual(@"<h1>one two three </h1><a href=""testurl""><b>four five </b></a><i><strong>some italic nested in string</strong></i> ...", TruncateHTMLSafeishWord( @"<h1>one two three </h1><a href=""testurl""><b>four five </b></a><i><strong>some italic nested in string</strong></i>", 99)); } [TestMethod] public void TestTruncateHTMLSafeishWordXML() { // zero case Assert.AreEqual(@" ...", TruncateHTMLSafeishWord( @"", 5)); // 'simple' nested none attributed tags string output = TruncateHTMLSafeishCharXML( @"<body><h1>one two </h1><b><i>three </i>four</b></body>", 13); Assert.AreEqual(@"<body>\r\n <h1>one two </h1>\r\n <b>\r\n <i>three</i>\r\n </b>\r\n</body>", output, "XML version, no ... yet and addeds '\r\n + spaces?' to format document"); // In middle of a! Assert.AreEqual(@"<h1>one two three </h1><a href=""testurl""><b class=""mrclass"">four ...</b></a>", TruncateHTMLSafeishCharXML( @"<body><h1>one two three </h1><a href=""testurl""><b class=""mrclass"">four five </b></a><i><strong>some italic nested in string</strong></i></body>", 4)); // start of h1 Assert.AreEqual(@"<h1>one two three ...</h1>", TruncateHTMLSafeishCharXML( @"<h1>one two three </h1><a href=""testurl""><b>four five </b></a><i><strong>some italic nested in string</strong></i>", 3)); // more than words available Assert.AreEqual(@"<h1>one two three </h1><a href=""testurl""><b>four five </b></a><i><strong>some italic nested in string</strong></i> ...", TruncateHTMLSafeishCharXML( @"<h1>one two three </h1><a href=""testurl""><b>four five </b></a><i><strong>some italic nested in string</strong></i>", 99)); } } }

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• Best WordPress Video Themes for a Video Blog

  - by Matt

  WordPress has made blogging so easy & fun, there are plenty of video blog themes that you can pick from. However there is always rarity in quality. We at JustSkins have gathered some high quality, tested, tried video themes list. We tried to find some WordPress themes for vloggers, we knew all along that there are very few yet some of them are just brilliant premium wordpress themes. More on that later, let’s find out some themes which you can install on your vlog right now. On Demand 2.0 A fully featured video WordPress premium theme from Press75. Includes  theme options panel for personal customization and content management options, post thumbnails, drop down navigation menu, custom widgets and lots more. Demo | Price: $75 | DOWNLOAD VideoZoom An outstanding premium WordPress video theme from WPZoom featuring standard video integration plus additionally it lets you play any video from all the popular video websites. VideoZoom theme also includes a featured video slider on the homepage, multiple post layout options, theme options panel, WordPress 3.0 menus, backgrounds etc. Demo | Price Single: $69, Developer: $149 | DOWNLOAD Vidley Press75′s easy to use premium WordPress video theme. This theme is full of great features, it can be a perfect choice if you intend to make it a portal someday..it is scalable to shape like a news portal or portfolios. The Theme is widget ready. It has ability to place Featured Content and Featured Category section on homepage. The drop down menus on this theme are nifty! Demo | Price $75 |  DOWNLOAD Live A video premium WordPress theme designed for streaming video, and live event broadcasting. You can embed live video broadcasts from third party services like Ustream etc, and features a prominent timer counting down to the next broadcast, rotating bumper images, Facebook and twitter integration for viewer interaction, theme admin options panel and more make this theme one of its kind. Demo | Price: $99, Support License: $149| DOWNLOAD Groovy Video Woo Themes is pioneer in making beautiful wordpress themes,  One such theme that is built by keeping the video blogger in mind. The Groovy Theme is very colourful video blog premium WordPress theme. Creating video posts is quick and easy with just a copy / paste of the video’s embed code. The theme enables automatic video resizing, plenty of widgets. Also allows you to pick color of your choice. Price: Single Use $70, Developer Price : $150 | DOWNLOAD Video Flick Another exciting Video blogging theme by Press75 is the Video Flick theme. Video Flick is compatible with any video service that provides embed code, or if you want to host your own videos, Video Flick is also compatible with FLV (Flash Video) and Quicktime formats. This theme allows you to either keep standard Blog and/or have Video posts. You can pick a light or dark color option. Demo | Price : $75 | DOWNLOAD Woo Tube An excellent video premium WordPress theme from Woothemes, the WooTube theme is a very easy video blog platform, as it comes with  automatic video resizing, a completely widgetised sidebar and 7 different colour schemes to choose from. The theme  has the ability to be used as a normal blog or a gallery. A very wise choice! Price: Single Use $70, Developer Price : $150 | DOWNLOAD eVid Theme One of the nicest WordPress theme designed specifically for the video bloggers. Simple to integrate videos from video hosts such as Youtube, Vimeo, Veoh, MetaCafe etc. Demo | Price: $19 | DOWNLOAD Tubular A video premium WordPress theme from StudioPress which can also be used as a used a simple website or a blog. The theme is also available in a light color version. Demo | Price: $59.95 | DOWNLOAD Video Elements 2.0 Another beautiful video premium WordPress theme from Press75. Video Elements 2.0 has been re-designed to include the features you need to easily run and maintain a video blog on WordPress. Demo | Price: $75 | DOWNLOAD TV Elements 3.0 The theme includes a featured video carousel on the homepage which can display any number of videos, a featured category section which displays up to 12 channels, creates automatic thumbnails and a lots more… Demo | Price: $75 | DOWNLOAD Wave A beautiful premium video wordpress theme, Flexible & Super cool looking. The Design has very earthy feel to it. The theme has featured video area & latest listing on the homepage. All in all a simple design no fancy features. Demo | Price: $35 | Download

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• A Quick Primer on SharePoint Customization

  - by PeterBrunone

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} This one goes out to all the people who have been asked to change the way a SharePoint site looks.  Management wants to know how long it will take, and you can whip that out by tomorrow, right?  If you don't have time to prepare a treatise on what's involved, or if you just want to lend some extra weight to your case by quoting a blogger who was an MVP for seven years, then dive right in; this post is for you. There are three main components of SharePoint visual customization:   1)       Theme – A theme encompasses all the standardized text formatting and coloring (borders, fonts, etc), including the background images of various sections. All told, there could be around 50 images involved, and a few hundred CSS (style) classes.  Installing a theme once it’s been created is no great feat.  Given the number of pieces, of course, creating a new theme could take anywhere from a day to a week… once decisions have been made about the desired appearance. 2)      Master Page – A master page provides the framework for page layout.  This includes all the top and side menus, where content shows up, et cetera.  Master pages have been around for a long time in ASP.NET (Microsoft’s web development platform), and they do require some .NET programming knowledge.  Beyond that, in SharePoint, there are a few dozen controls which the system expects find on a given page.  They’re not all used at once, but if they’re not there when they’re needed, chaos ensues.  Estimating a custom master page is difficult, as it depends on the level of customization.  I’ve been on projects where I was brought in simply to fix some problems and add a few finishing touches, and it took 2-3 weeks.  Master page customization requires a large amount of testing time to make sure that the HTML, JavaScript, CSS, and control placement all work well together. 3)      Individual page layout – Each page (ideally) uses a master page for its template, but within the content areas defined by the master page, web parts can be added, removed, and configured from within the browser.  The wireframe that Brent provided could most likely be completed simply by manipulating the content on the home page in this fashion, and we had allowed about a day of effort for the task.  If needed, further functionality can be provided by an experienced ASP.NET developer; custom forms are a common example.  This of course is a bit more in-depth than simple content manipulation and could take several days per page (or more; there’s really no way to quantify this without a set of requirements).   That’s basically it.  To recap:  Fonts and coloring are done with themes, and can take anywhere from a day to a week to create (not counting creative time); required technical skills include HTML, CSS, and image manipulation.  Templated layout is done with master pages, and generally requires a developer familiar with both ASP.NET and SharePoint in particular; it can have far-reaching consequences depending on the complexity of the changes, and could add weeks or months to a project.  Page layout can be as simple as content manipulation in the web browser, taking a few hours per page, or it can involve more detail, like custom forms, and can require programming expertise and significantly more development time.

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• Spolskism or Twitterism: A Doctor writes...

  - by Phil Factor

  "I never realized I had a problem. I just 'twittered' because it was a social thing to do. All my mates were doing it. It made me feel good to have 'followers'; it bolstered my self-esteem. Of course, you don't think of the long-term effects on your work and on the way you think. There's no denying that it impairs your judgment…" Yes, this story is typical. Hundreds of people are waking up to the long term effects of twittering, and seeking help. Dave, who wishes to remain anonymous, told our reporter… "I started using Twitter at work. Just a few minutes now and then, throughout the day. A lot of my colleagues were doing it and I thought 'Well, that's cool; it must be part of what I should be doing at work'. Soon, I was avidly reading every twitter that came my way, and counting the minutes between my own twitters. I tried to kid myself that it was all about professional development and getting other people to help you with work-related problems, but in truth I had become addicted to the buzz of the social network. The worse thing was that it made me seem busy even when I was really just frittering my time away. Inevitably, I started to get behind with my real work." Experts have identified the syndrome and given it a name: 'Twitterism', sometimes referred to as 'Spolskism', after the person who first drew attention to the pernicious damage to well-being that the practice caused, and who had the courage to take the pledge of rejecting it. According to one expert… "The occasional Twitter does little harm to the participant, and can be an adaptive way of dealing with stress. Unfortunately, it rarely stops there. The addictive qualities of the practice have put a strain on the caring professions who are faced with a flood of people making that first bold step to seeking help". Dave is one of those now seeking help for his addiction… "I had lost touch with reality. Even though I twittered my work colleagues constantly, I found I actually spoke to them less and less. Even when out socializing, I would frequently disengage from the conversation, in order to twitter. I stopped blogging. I stopped responding to emails; the only way to reach me was through the world of Twitter. Unfortunately, my denial about the harm that twittering was doing to me, my friends, and my work-colleagues was so strong that I truly couldn't see that I had a problem." Like other addictions, the help and support of others who are 'taking the cure' is important. There is a common bond between those who have 'been through hell and back' and are once more able to experience the joys of actually conversing and socializing, rather than the false comfort of solitary 'twittering'. Complete abstinence is essential to the cure. Most of those who risk even an occasional twitter face a headlong slide back into 'binge' twittering. Tom, another twitterer who has managed to kick the habit explains… "My twittering addiction now seems more like a bad dream. You get to work, and switch on the PC. You say to yourself, just open up the browser, just for a minute, just to see what people are saying on Twitter. The next thing you know, half the day has gone by. The worst thing is that when you're addicted, you get good at covering up the habit; I spent so much time looking at the screen and typing on the keyboard, people just assumed I was working hard.I know that I must never forget what it was like then, and what it's like now that I've kicked the habit. I now have more time for productive work and a real social life." Like many addictions, Spolskism has its most detrimental effects on family, friends and workmates, rather than the addict. So often nowadays, we hear the sad stories of Twitter-Widows; tales of long lonely evenings spent whilst their partners are engrossed in their twittering into their 'mobiles' or indulging in their solitary spolskistic habits in privacy, under cover of 'having to do work at home'. Workmates suffer too, when the addicts even take their laptops or mobiles into meetings in order to 'twitter' with their fellow obsessives, even stooping to complain to their followers how boring the meeting is. No; The best advice is to leave twittering to the birds. You know it makes sense.

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• Ranking - an Introduction

  - by PointsToShare

  © 2011 By: Dov Trietsch. All rights reserved Ranking Ranking is quite common in the internet. Readers are asked to rank their latest reading by clicking on one of 5 (sometimes 10) stars. The number of stars is then converted to a number and the average number of stars as selected by all the readers is proudly (or shamefully) displayed for future readers. SharePoint 2007 lacked this feature altogether. SharePoint 2010 allows the users to rank items in a list or documents in a library (the two are actually the same because a library is actually a list). But in SP2010 the computation of the average is done later on a timer rather than on-the-spot as it should be. I suspect that the reason for this shortcoming is that they did not involve a mathematician! Let me explain. Ranking is kept in a related list. When a user rates a document the rank-list is added an item with the item id, the user name, and his number of stars. The fact that a user already ranked an item prevents him from ranking it again. This prevents the creator of the item from asking his mother to rank it a 5 and do it 753 times, thus stacking the ballot. Some systems will allow a user to change his rating and this will be done by updating the rank-list item. Now, when the timer kicks off, the list is spanned and for each item the rank-list items containing this id are summed up and divided by the number of votes thus yielding the new average. This is obviously very time consuming and very server intensive. In the 18th century an early actuary named James Dodson used what the great Augustus De Morgan (of De Morgan’s law) later named Commutation tables. The labor involved in computing a life insurance premium was staggering and also very error prone. Clerks with pencil and paper would multiply and add mountains of numbers to do the task. The more steps the greater the probability of error and the more expensive the process. Commutation tables created a “summary” of many steps and reduced the work 100 fold. So had Microsoft taken a lesson in the history of computation, they would have developed a much faster way for rating that may be done in real-time and is also 100 times faster and less CPU intensive. How do we do this? We use a form of commutation. We always keep the number of votes and the total of stars. One simple division gives us the average. So we write an event receiver. When a vote is added, we just add the stars to the total-stars and 1 to the number of votes. We then recomputed the average. When a vote is updated, we reduce the total by the old vote, increase it by the new vote and leave the number of votes the same. Again we do the division to get the new average. When a vote is deleted (highly unlikely and maybe even prohibited), we reduce the total by that vote and reduce the number of votes by 1… Gone are the days of spanning lists, counting items, and tallying votes and we have no need for a timer process to run it all. This is the first of a few treatises on ranking. Even though I discussed the math and the history thereof, in here I am only going to solve the presentation issue. I wanted to create the CSS and Jscript needed to display the stars, create the various effects like hovering and clicking (onmouseover, onmouseout, onclick, etc.) and I wanted to create a general solution with any number of stars. When I had it all done, I created the ranking game so that I could test it. The game is interesting in and on itself, so here it is (or go to the games page and select “rank the stars”). BTW, when you play it, look at the source code and see how it was all done.  Next, how the 5 stars are displayed in the New and Update forms. When the whole set of articles will be done, you’ll be able to create the complete solution. That’s all folks!

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• RTS Voxel Engine using LWJGL - Textures glitching

  - by Dieter Hubau

  I'm currently working on an RTS game engine using voxels. I have implemented a basic chunk manager using an Octree of Octrees which contains my voxels (simple square blocks, as in Minecraft). I'm using a Voronoi-based terrain generation to get a simplistic yet relatively realistic heightmap. I have no problem showing a 256*256*256 grid of voxels with a decent framerate (250), because of frustum culling, face culling and only rendering visible blocks. For example, in a random voxel grid of 256*256*256 I generally only render 100k-120k faces, not counting frustum culling. Frustum culling is only called every 100ms, since calling it every frame seemed a bit overkill. Now I have reached the stage of texturing and I'm experiencing some problems: Some experienced people might already see the problem, but if we zoom in, you can see the glitches more clearly: All the seams between my blocks are glitching and kind of 'overlapping' or something. It's much more visible when you're moving around. I'm using a single, simple texture map to draw on my cubes, where each texture is 16*16 pixels big: I have added black edges around the textures to get a kind of cellshaded look, I think it's cool. The texture map has 256 textures of each 16*16 pixels, meaning the total size of my texture map is 256*256 pixels. The code to update the ChunkManager: public void update(ChunkManager chunkManager) { for (Octree<Cube> chunk : chunks) { if (chunk.getId() < 0) { // generate an id for the chunk to be able to call it later chunk.setId(glGenLists(1)); } glNewList(chunk.getId(), GL_COMPILE); glBegin(GL_QUADS); faces += renderChunk(chunk); glEnd(); glEndList(); } } Where my renderChunk method is: private int renderChunk(Octree<Cube> node) { // keep track of the number of visible faces in this chunk int faces = 0; if (!node.isEmpty()) { if (node.isLeaf()) { faces += renderItem(node); } List<Octree<Cube>> children = node.getChildren(); if (children != null && !children.isEmpty()) { for (Octree<Cube> child : children) { faces += renderChunk(child); } } return faces; } Where my renderItem method is the following: private int renderItem(Octree<Cube> node) { Cube cube = node.getItem(-1, -1, -1); int faces = 0; float x = node.getPosition().x; float y = node.getPosition().y; float z = node.getPosition().z; float size = cube.getSize(); Vector3f point1 = new Vector3f(-size + x, -size + y, size + z); Vector3f point2 = new Vector3f(-size + x, size + y, size + z); Vector3f point3 = new Vector3f(size + x, size + y, size + z); Vector3f point4 = new Vector3f(size + x, -size + y, size + z); Vector3f point5 = new Vector3f(-size + x, -size + y, -size + z); Vector3f point6 = new Vector3f(-size + x, size + y, -size + z); Vector3f point7 = new Vector3f(size + x, size + y, -size + z); Vector3f point8 = new Vector3f(size + x, -size + y, -size + z); TextureCoordinates tc = textureManager.getTextureCoordinates(cube.getCubeType()); // front face if (cube.isVisible(CubeSide.FRONT)) { faces++; glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point1.x, point1.y, point1.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point4.x, point4.y, point4.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point3.x, point3.y, point3.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point2.x, point2.y, point2.z); } // back face if (cube.isVisible(CubeSide.BACK)) { faces++; glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point5.x, point5.y, point5.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point6.x, point6.y, point6.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point7.x, point7.y, point7.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point8.x, point8.y, point8.z); } // left face if (cube.isVisible(CubeSide.SIDE_LEFT)) { faces++; glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point5.x, point5.y, point5.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point1.x, point1.y, point1.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point2.x, point2.y, point2.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point6.x, point6.y, point6.z); } // ETC ETC return faces; } When all this is done, I simply render my lists every frame, like this: public void render(ChunkManager chunkManager) { glBindTexture(GL_TEXTURE_2D, textureManager.getCubeTextureId()); // load all chunks from the tree List<Octree<Cube>> chunks = chunkManager.getTree().getAllItems(); for (Octree<Cube> chunk : chunks) { if (frustum.cubeInFrustum(chunk.getPosition(), chunk.getSize() / 2)) { glCallList(chunk.getId()); } } } I don't know if anyone is willing to go through all of this code or maybe you can spot the problem right away, but that is basically the problem, and I can't find a solution :-) Thanks for reading and any help is appreciated!

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• Frameskipping in Android gameloop causing choppy sprites (Open GL ES 2.0)

  - by user22241

  I have written a simple 2d platform game for Android and am wondering how one deals with frame-skipping? Are there any alternatives? Let me explain further. So, my game loop allows for the rendering to be skipped if game updates and rendering do not fit into my fixed time-slice (16.667ms). This allows my game to run at identically perceived speeds on different devices. And this works great, things do run at the same speed. However, when the gameloop skips a render call for even one frame, the sprite glitches. And thinking about it, why wouldn't it? You're seeing a sprite move say, an average of 10 pixels every 1.6 seconds, then suddenly, there is a pause of 3.2ms, and the sprite then appears to jump 20 pixels. When this happens 3 or 4 times in close succession, the result is very ugly and not something I want in my game. Therfore, my question is how does one deal with these 'pauses' and 'jumps' - I've read every article on game loops I can find (see below) and my loops are even based off of code from these articles. The articles specifically mention frame skipping but they don't make any reference to how to deal with visual glitches that result from it. I've attempted various game-loops. My loop must have a mechanism in-place to allow rendering to be skipped to keep game-speed constant across multiple devices (or alternative, if one exists) I've tried interpolation but this doesn't eliminate this specific problem (although it looks like it may mitigate the issue slightly as when it eventually draws the sprite it 'moves it back' between the old and current positions so the 'jump' isn't so big. I've also tried a form of extrapolation which does seem to keep things smooth considerably, but I find it to be next to completely useless because it plays havoc with my collision detection (even when drawing with a 'display only' coordinate - see extrapolation-breaks-collision-detection) I've tried a loop that uses Thread.sleep when drawing / updating completes with time left over, no frame skipping in this one, again fairly smooth, but runs differently on different devices so no good. And I've tried spawning my own, third thread for logic updates, but this, was extremely messy to deal with and the performance really wasn't good. (upon reading tons of forums, most people seem to agree a 2 thread loops ( so UI and GL threads) is safer / easier). Now if I remove frame skipping, then all seems to run nice and smooth, with or without inter/extrapolation. However, this isn't an option because the game then runs at different speeds on different devices as it falls behind from not being able to render fast enough. I'm running logic at 60 Ticks per second and rendering as fast as I can. I've read, as far as I can see every article out there, I've tried the loops from My Secret Garden and Fix your timestep. I've also read: Against the grain deWITTERS Game Loop Plus various other articles on Game-loops. A lot of the others are derived from the above articles or just copied word for word. These are all great, but they don't touch on the issues I'm experiencing. I really have tried everything I can think of over the course of a year to eliminate these glitches to no avail, so any and all help would be appreciated. A couple of examples of my game loops (Code follows): From My Secret Room public void onDrawFrame(GL10 gl) { //Rre-set loop back to 0 to start counting again loops=0; while(System.currentTimeMillis() > nextGameTick && loops < maxFrameskip) { SceneManager.getInstance().getCurrentScene().updateLogic(); nextGameTick += skipTicks; timeCorrection += (1000d / ticksPerSecond) % 1; nextGameTick += timeCorrection; timeCorrection %= 1; loops++; } extrapolation = (float)(System.currentTimeMillis() + skipTicks - nextGameTick) / (float)skipTicks; render(extrapolation); } And from Fix your timestep double t = 0.0; double dt2 = 0.01; double currentTime = System.currentTimeMillis()*0.001; double accumulator = 0.0; double newTime; double frameTime; @Override public void onDrawFrame(GL10 gl) { newTime = System.currentTimeMillis()*0.001; frameTime = newTime - currentTime; if ( frameTime > (dt*5)) //Allow 5 'skips' frameTime = (dt*5); currentTime = newTime; accumulator += frameTime; while ( accumulator >= dt ) { SceneManager.getInstance().getCurrentScene().updateLogic(); previousState = currentState; accumulator -= dt; } interpolation = (float) (accumulator / dt); render(interpolation); }

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