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• AdvancedFormatProvider: Making string.format do more

  - by plblum

  When I have an integer that I want to format within the String.Format() and ToString(format) methods, I’m always forgetting the format symbol to use with it. That’s probably because its not very intuitive. Use {0:N0} if you want it with group (thousands) separators. text = String.Format("{0:N0}", 1000); // returns "1,000"   int value1 = 1000; text = value1.ToString("N0"); Use {0:D} or {0:G} if you want it without group separators. text = String.Format("{0:D}", 1000); // returns "1000"   int value2 = 1000; text2 = value2.ToString("D"); The {0:D} is especially confusing because Microsoft gives the token the name “Decimal”. I thought it reasonable to have a new format symbol for String.Format, "I" for integer, and the ability to tell it whether it shows the group separators. Along the same lines, why not expand the format symbols for currency ({0:C}) and percent ({0:P}) to let you omit the currency or percent symbol, omit the group separator, and even to drop the decimal part when the value is equal to the whole number? My solution is an open source project called AdvancedFormatProvider, a group of classes that provide the new format symbols, continue to support the rest of the native symbols and makes it easy to plug in additional format symbols. Please visit https://github.com/plblum/AdvancedFormatProvider to learn about it in detail and explore how its implemented. The rest of this post will explore some of the concepts it takes to expand String.Format() and ToString(format). AdvancedFormatProvider benefits: Supports {0:I} token for integers. It offers the {0:I-,} option to omit the group separator. Supports {0:C} token with several options. {0:C-$} omits the currency symbol. {0:C-,} omits group separators, and {0:C-0} hides the decimal part when the value would show “.00”. For example, 1000.0 becomes “$1000” while 1000.12 becomes “$1000.12”. Supports {0:P} token with several options. {0:P-%} omits the percent symbol. {0:P-,} omits group separators, and {0:P-0} hides the decimal part when the value would show “.00”. For example, 1 becomes “100 %” while 1.1223 becomes “112.23 %”. Provides a plug in framework that lets you create new formatters to handle specific format symbols. You register them globally so you can just pass the AdvancedFormatProvider object into String.Format and ToString(format) without having to figure out which plug ins to add. text = String.Format(AdvancedFormatProvider.Current, "{0:I}", 1000); // returns "1,000" text2 = String.Format(AdvancedFormatProvider.Current, "{0:I-,}", 1000); // returns "1000" text3 = String.Format(AdvancedFormatProvider.Current, "{0:C-$-,}", 1000.0); // returns "1000.00" The IFormatProvider parameter Microsoft has made String.Format() and ToString(format) format expandable. They each take an additional parameter that takes an object that implements System.IFormatProvider. This interface has a single member, the GetFormat() method, which returns an object that knows how to convert the format symbol and value into the desired string. There are already a number of web-based resources to teach you about IFormatProvider and the companion interface ICustomFormatter. I’ll defer to them if you want to dig more into the topic. The only thing I want to point out is what I think are implementation considerations. Why GetFormat() always tests for ICustomFormatter When you see examples of implementing IFormatProviders, the GetFormat() method always tests the parameter against the ICustomFormatter type. Why is that? public object GetFormat(Type formatType) { if (formatType == typeof(ICustomFormatter)) return this; else return null; } The value of formatType is already predetermined by the .net framework. String.Format() uses the StringBuilder.AppendFormat() method to parse the string, extracting the tokens and calling GetFormat() with the ICustomFormatter type. (The .net framework also calls GetFormat() with the types of System.Globalization.NumberFormatInfo and System.Globalization.DateTimeFormatInfo but these are exclusive to how the System.Globalization.CultureInfo class handles its implementation of IFormatProvider.) Your code replaces instead of expands I would have expected the caller to pass in the format string to GetFormat() to allow your code to determine if it handles the request. My vision would be to return null when the format string is not supported. The caller would iterate through IFormatProviders until it finds one that handles the format string. Unfortunatley that is not the case. The reason you write GetFormat() as above is because the caller is expecting an object that handles all formatting cases. You are effectively supposed to write enough code in your formatter to handle your new cases and call .net functions (like String.Format() and ToString(format)) to handle the original cases. Its not hard to support the native functions from within your ICustomFormatter.Format function. Just test the format string to see if it applies to you. If not, call String.Format() with a token using the format passed in. public string Format(string format, object arg, IFormatProvider formatProvider) { if (format.StartsWith("I")) { // handle "I" formatter } else return String.Format(formatProvider, "{0:" + format + "}", arg); } Formatters are only used by explicit request Each time you write a custom formatter (implementer of ICustomFormatter), it is not used unless you explicitly passed an IFormatProvider object that supports your formatter into String.Format() or ToString(). This has several disadvantages: Suppose you have several ICustomFormatters. In order to have all available to String.Format() and ToString(format), you have to merge their code and create an IFormatProvider to return an instance of your new class. You have to remember to utilize the IFormatProvider parameter. Its easy to overlook, especially when you have existing code that calls String.Format() without using it. Some APIs may call String.Format() themselves. If those APIs do not offer an IFormatProvider parameter, your ICustomFormatter will not be available to them. The AdvancedFormatProvider solves the first two of these problems by providing a plug-in architecture.

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• Is Code Complete still Code Complete? [closed]

  - by Peter Turner

  It's been quite a few years since Code Complete was published. I really love the book, I keep it in the bathroom at the office and read a little out of it once or twice a day. But I don't think it's possible to call Code Complete, "Code Complete" when it doesn't have language features that even Delphi has, like anonymous methods and generics. What key sections are missing from this book, and what should be deprecated?

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• Easier ASP.NET MVC Routing

  - by Steve Wilkes

  I've recently refactored the way Routes are declared in an ASP.NET MVC application I'm working on, and I wanted to share part of the system I came up with; a really easy way to declare and keep track of ASP.NET MVC Routes, which then allows you to find the name of the Route which has been selected for the current request. Traditional MVC Route Declaration Traditionally, ASP.NET MVC Routes are added to the application's RouteCollection using overloads of the RouteCollection.MapRoute() method; for example, this is the standard way the default Route which matches /controller/action URLs is created: routes.MapRoute(     "Default",     "{controller}/{action}/{id}",     new { controller = "Home", action = "Index", id = UrlParameter.Optional }); The first argument declares that this Route is to be named 'Default', the second specifies the Route's URL pattern, and the third contains the URL pattern segments' default values. To then write a link to a URL which matches the default Route in a View, you can use the HtmlHelper.RouteLink() method, like this: @ this.Html.RouteLink("Default", new { controller = "Orders", action = "Index" }) ...that substitutes 'Orders' into the {controller} segment of the default Route's URL pattern, and 'Index' into the {action} segment. The {Id} segment was declared optional and isn't specified here. That's about the most basic thing you can do with MVC routing, and I already have reservations: I've duplicated the magic string "Default" between the Route declaration and the use of RouteLink(). This isn't likely to cause a problem for the default Route, but once you get to dozens of Routes the duplication is a pain. There's no easy way to get from the RouteLink() method call to the declaration of the Route itself, so getting the names of the Route's URL parameters correct requires some effort. The call to MapRoute() is quite verbose; with dozens of Routes this gets pretty ugly. If at some point during a request I want to find out the name of the Route has been matched.... and I can't. To get around these issues, I wanted to achieve the following: Make declaring a Route very easy, using as little code as possible. Introduce a direct link between where a Route is declared, where the Route is defined and where the Route's name is used, so I can use Visual Studio's Go To Definition to get from a call to RouteLink() to the declaration of the Route I'm using, making it easier to make sure I use the correct URL parameters. Create a way to access the currently-selected Route's name during the execution of a request. My first step was to come up with a quick and easy syntax for declaring Routes. 1 . An Easy Route Declaration Syntax I figured the easiest way of declaring a route was to put all the information in a single string with a special syntax. For example, the default MVC route would be declared like this: "{controller:Home}/{action:Index}/{Id}*" This contains the same information as the regular way of defining a Route, but is far more compact: The default values for each URL segment are specified in a colon-separated section after the segment name The {Id} segment is declared as optional simply by placing a * after it That's the default route - a pretty simple example - so how about this? routes.MapRoute(     "CustomerOrderList",     "Orders/{customerRef}/{pageNo}",     new { controller = "Orders", action = "List", pageNo = UrlParameter.Optional },     new { customerRef = "^[a-zA-Z0-9]+$", pageNo = "^[0-9]+$" }); This maps to the List action on the Orders controller URLs which: Start with the string Orders/ Then have a {customerRef} set of characters and numbers Then optionally a numeric {pageNo}. And again, it’s quite verbose. Here's my alternative: "Orders/{customerRef:^[a-zA-Z0-9]+$}/{pageNo:^[0-9]+$}*->Orders/List" Quite a bit more brief, and again, containing the same information as the regular way of declaring Routes: Regular expression constraints are declared after the colon separator, the same as default values The target controller and action are specified after the -> The {pageNo} is defined as optional by placing a * after it With an appropriate parser that gave me a nice, compact and clear way to declare routes. Next I wanted to have a single place where Routes were declared and accessed. 2. A Central Place to Declare and Access Routes I wanted all my Routes declared in one, dedicated place, which I would also use for Route names when calling RouteLink(). With this in mind I made a single class named Routes with a series of public, constant fields, each one relating to a particular Route. With this done, I figured a good place to actually declare each Route was in an attribute on the field defining the Route’s name; the attribute would parse the Route definition string and make the resulting Route object available as a property. I then made the Routes class examine its own fields during its static setup, and cache all the attribute-created Route objects in an internal Dictionary. Finally I made Routes use that cache to register the Routes when requested, and to access them later when required. So the Routes class declares its named Routes like this: public static class Routes{     [RouteDefinition("Orders/{customerName}->Orders/Index")]     public const string OrdersCustomerIndex = "OrdersCustomerIndex";     [RouteDefinition("Orders/{customerName}/{orderId:^([0-9]+)$}->Orders/Details")]     public const string OrdersDetails = "OrdersDetails";     [RouteDefinition("{controller:Home}*/{action:Index}*")]     public const string Default = "Default"; } ...which are then used like this: @ this.Html.RouteLink(Routes.Default, new { controller = "Orders", action = "Index" }) Now that using Go To Definition on the Routes.Default constant takes me to where the Route is actually defined, it's nice and easy to quickly check on the parameter names when using RouteLink(). Finally, I wanted to be able to access the name of the current Route during a request. 3. Recovering the Route Name The RouteDefinitionAttribute creates a NamedRoute class; a simple derivative of Route, but with a Name property. When the Routes class examines its fields and caches all the defined Routes, it has access to the name of the Route through the name of the field against which it is defined. It was therefore a pretty easy matter to have Routes give NamedRoute its name when it creates its cache of Routes. This means that the Route which is found in RequestContext.RouteData.Route is now a NamedRoute, and I can recover the Route's name during a request. For visibility, I made NamedRoute.ToString() return the Route name and URL pattern, like this: The screenshot is from an example project I’ve made on bitbucket; it contains all the named route classes and an MVC 3 application which demonstrates their use. I’ve found this way of defining and using Routes much tidier than the default MVC system, and you find it useful too

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• Chunking a List - .NET vs Python

  - by Abhijeet Patel

  Chunking a List As I mentioned last time, I'm knee deep in python these days. I come from a statically typed background so it's definitely a mental adjustment. List comprehensions is BIG in Python and having worked with a few of them I can see why. Let's say we need to chunk a list into sublists of a specified size. Here is how we'd do it in C#  static class Extensions   {       public static IEnumerable<List<T>> Chunk<T>(this List<T> l, int chunkSize)       {           if (chunkSize <0)           {               throw new ArgumentException("chunkSize cannot be negative", "chunkSize");           }           for (int i = 0; i < l.Count; i += chunkSize)           {               yield return new List<T>(l.Skip(i).Take(chunkSize));           }       }    }    static void Main(string[] args)  {           var l = new List<string> { "a", "b", "c", "d", "e", "f","g" };             foreach (var list in l.Chunk(7))           {               string str = list.Aggregate((s1, s2) => s1 + "," + s2);               Console.WriteLine(str);           }   }   A little wordy but still pretty concise thanks to LINQ.We skip the iteration number plus chunkSize elements and yield out a new List of chunkSize elements on each iteration. The python implementation is a bit more terse. def chunkIterable(iter, chunkSize):      '''Chunks an iterable         object into a list of the specified chunkSize     '''        assert hasattr(iter, "__iter__"), "iter is not an iterable"      for i in xrange(0, len(iter), chunkSize):          yield iter[i:i + chunkSize]    if __name__ == '__main__':      l = ['a', 'b', 'c', 'd', 'e', 'f']      generator = chunkIterable(l,2)      try:          while(1):              print generator.next()      except StopIteration:          pass   xrange generates elements in the specified range taking in a seed and returning a generator. which can be used in a for loop(much like using a C# iterator in a foreach loop) Since chunkIterable has a yield statement, it turns this method into a generator as well. iter[i:i + chunkSize] essentially slices the list based on the current iteration index and chunksize and creates a new list that we yield out to the caller one at a time. A generator much like an iterator is a state machine and each subsequent call to it remembers the state at which the last call left off and resumes execution from that point. The caveat to keep in mind is that since variables are not explicitly typed we need to ensure that the object passed in is iterable using hasattr(iter, "__iter__").This way we can perform chunking on any object which is an "iterable", very similar to accepting an IEnumerable in the .NET land

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• Global Webcast: Increase Pharmaceutical Sales Effectiveness

  - by charles.knapp

  See a next-generation approach to Pharmaceutical sales challenges! • Increase the quality of sales interactions with enhanced call planning and eDetailing • Improve sample management with electronic signature storage and inventory tracking on the go • Increase marketing effectiveness with closed loop marketing and personalized content delivery Watch as senior vice president of CRM, Anthony Lye, and director of life sciences product strategy, Piers Evans, provide the first public look at Oracle's new Pharmaceutical Sales On The Go solution, powered by Oracle CRM On Demand Release 17 -- Life Sciences Edition. Register now for this informative GLOBAL webcast on March 31, 9 AM PDT/4 PM GMT.

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• Using MAC Authentication for simple Web API’s consumption

  - by cibrax

  For simple scenarios of Web API consumption where identity delegation is not required, traditional http authentication schemas such as basic, certificates or digest are the most used nowadays. All these schemas rely on sending the caller credentials or some representation of it in every request message as part of the Authorization header, so they are prone to suffer phishing attacks if they are not correctly secured at transport level with https. In addition, most client applications typically authenticate two different things, the caller application and the user consuming the API on behalf of that application. For most cases, the schema is simplified by using a single set of username and password for authenticating both, making necessary to store those credentials temporally somewhere in memory. The true is that you can use two different identities, one for the user running the application, which you might authenticate just once during the first call when the application is initialized, and another identity for the application itself that you use on every call. Some cloud vendors like Windows Azure or Amazon Web Services have adopted an schema to authenticate the caller application based on a Message Authentication Code (MAC) generated with a symmetric algorithm using a key known by the two parties, the caller and the Web API. The caller must include a MAC as part of the Authorization header created from different pieces of information in the request message such as the address, the host, and some other headers. The Web API can authenticate the caller by using the key associated to it and validating the attached MAC in the request message. In that way, no credentials are sent as part of the request message, so there is no way an attacker to intercept the message and get access to those credentials. Anyways, this schema also suffers from some deficiencies that can generate attacks. For example, brute force can be still used to infer the key used for generating the MAC, and impersonate the original caller. This can be mitigated by renewing keys in a relative short period of time. This schema as any other can be complemented with transport security. Eran Rammer, one of the brains behind OAuth, has recently published an specification of a protocol based on MAC for Http authentication called Hawk. The initial version of the spec is available here. A curious fact is that the specification per se does not exist, and the specification itself is the code that Eran initially wrote using node.js. In that implementation, you can associate a key to an user, so once the MAC has been verified on the Web API, the user can be inferred from that key. Also a timestamp is used to avoid replay attacks. As a pet project, I decided to port that code to .NET using ASP.NET Web API, which is available also in github under https://github.com/pcibraro/hawknet Enjoy!.

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• Flow-Design Cheat Sheet &ndash; Part I, Notation

  - by Ralf Westphal

  You want to avoid the pitfalls of object oriented design? Then this is the right place to start. Use Flow-Oriented Analysis (FOA) and –Design (FOD or just FD for Flow-Design) to understand a problem domain and design a software solution. Flow-Orientation as described here is related to Flow-Based Programming, Event-Based Programming, Business Process Modelling, and even Event-Driven Architectures. But even though “thinking in flows” is not new, I found it helpful to deviate from those precursors for several reasons. Some aim at too big systems for the average programmer, some are concerned with only asynchronous processing, some are even not very much concerned with programming at all. What I was looking for was a design method to help in software projects of any size, be they large or tiny, involing synchronous or asynchronous processing, being local or distributed, running on the web or on the desktop or on a smartphone. That´s why I took ideas from all of the above sources and some additional and came up with Event-Based Components which later got repositioned and renamed to Flow-Design. In the meantime this has generated some discussion (in the German developer community) and several teams have started to work with Flow-Design. Also I´ve conducted quite some trainings using Flow-Orientation for design. The results are very promising. Developers find it much easier to design software using Flow-Orientation than OOAD-based object orientation. Since Flow-Orientation is moving fast and is not covered completely by a single source like a book, demand has increased for at least an overview of the current state of its notation. This page is trying to answer this demand by briefly introducing/describing every notational element as well as their translation into C# source code. Take this as a cheat sheet to put next to your whiteboard when designing software. However, please do not expect any explanation as to the reasons behind Flow-Design elements. Details on why Flow-Design at all and why in this specific way you´ll find in the literature covering the topic. Here´s a resource page on Flow-Design/Event-Based Components, if you´re able to read German. Notation Connected Functional Units The basic element of any FOD are functional units (FU): Think of FUs as some kind of software code block processing data. For the moment forget about classes, methods, “components”, assemblies or whatever. See a FU as an abstract piece of code. Software then consists of just collaborating FUs. I´m using circles/ellipses to draw FUs. But if you like, use rectangles. Whatever suites your whiteboard needs best.   The purpose of FUs is to process input and produce output. FUs are transformational. However, FUs are not called and do not call other FUs. There is no dependency between FUs. Data just flows into a FU (input) and out of it (output). From where and where to is of no concern to a FU.   This way FUs can be concatenated in arbitrary ways:   Each FU can accept input from many sources and produce output for many sinks:   Flows Connected FUs form a flow with a start and an end. Data is entering a flow at a source, and it´s leaving it through a sink. Think of sources and sinks as special FUs which conntect wires to the environment of a network of FUs.   Wiring Details Data is flowing into/out of FUs through wires. This is to allude to electrical engineering which since long has been working with composable parts. Wires are attached to FUs usings pins. They are the entry/exit points for the data flowing along the wires. Input-/output pins currently need not be drawn explicitly. This is to keep designing on a whiteboard simple and quick.   Data flowing is of some type, so wires have a type attached to them. And pins have names. If there is only one input pin and output pin on a FU, though, you don´t need to mention them. The default is Process for a single input pin, and Result for a single output pin. But you´re free to give even single pins different names.   There is a shortcut in use to address a certain pin on a destination FU:   The type of the wire is put in parantheses for two reasons. 1. This way a “no-type” wire can be easily denoted, 2. this is a natural way to describe tuples of data.   To describe how much data is flowing, a star can be put next to the wire type:   Nesting – Boards and Parts If more than 5 to 10 FUs need to be put in a flow a FD starts to become hard to understand. To keep diagrams clutter free they can be nested. You can turn any FU into a flow: This leads to Flow-Designs with different levels of abstraction. A in the above illustration is a high level functional unit, A.1 and A.2 are lower level functional units. One of the purposes of Flow-Design is to be able to describe systems on different levels of abstraction and thus make it easier to understand them. Humans use abstraction/decomposition to get a grip on complexity. Flow-Design strives to support this and make levels of abstraction first class citizens for programming. You can read the above illustration like this: Functional units A.1 and A.2 detail what A is supposed to do. The whole of A´s responsibility is decomposed into smaller responsibilities A.1 and A.2. FU A thus does not do anything itself anymore! All A is responsible for is actually accomplished by the collaboration between A.1 and A.2. Since A now is not doing anything anymore except containing A.1 and A.2 functional units are devided into two categories: boards and parts. Boards are just containing other functional units; their sole responsibility is to wire them up. A is a board. Boards thus depend on the functional units nested within them. This dependency is not of a functional nature, though. Boards are not dependent on services provided by nested functional units. They are just concerned with their interface to be able to plug them together. Parts are the workhorses of flows. They contain the real domain logic. They actually transform input into output. However, they do not depend on other functional units. Please note the usage of source and sink in boards. They correspond to input-pins and output-pins of the board.   Implicit Dependencies Nesting functional units leads to a dependency tree. Boards depend on nested functional units, they are the inner nodes of the tree. Parts are independent, they are the leafs: Even though dependencies are the bane of software development, Flow-Design does not usually draw these dependencies. They are implicitly created by visually nesting functional units. And they are harmless. Boards are so simple in their functionality, they are little affected by changes in functional units they are depending on. But functional units are implicitly dependent on more than nested functional units. They are also dependent on the data types of the wires attached to them: This is also natural and thus does not need to be made explicit. And it pertains mainly to parts being dependent. Since boards don´t do anything with regard to a problem domain, they don´t care much about data types. Their infrastructural purpose just needs types of input/output-pins to match.   Explicit Dependencies You could say, Flow-Orientation is about tackling complexity at its root cause: that´s dependencies. “Natural” dependencies are depicted naturally, i.e. implicitly. And whereever possible dependencies are not even created. Functional units don´t know their collaborators within a flow. This is core to Flow-Orientation. That makes for high composability of functional units. A part is as independent of other functional units as a motor is from the rest of the car. And a board is as dependend on nested functional units as a motor is on a spark plug or a crank shaft. With Flow-Design software development moves closer to how hardware is constructed. Implicit dependencies are not enough, though. Sometimes explicit dependencies make designs easier – as counterintuitive this might sound. So FD notation needs a ways to denote explicit dependencies: Data flows along wires. But data does not flow along dependency relations. Instead dependency relations represent service calls. Functional unit C is depending on/calling services on functional unit S. If you want to be more specific, name the services next to the dependency relation: Although you should try to stay clear of explicit dependencies, they are fundamentally ok. See them as a way to add another dimension to a flow. Usually the functionality of the independent FU (“Customer repository” above) is orthogonal to the domain of the flow it is referenced by. If you like emphasize this by using different shapes for dependent and independent FUs like above. Such dependencies can be used to link in resources like databases or shared in-memory state. FUs can not only produce output but also can have side effects. A common pattern for using such explizit dependencies is to hook a GUI into a flow as the source and/or the sink of data: Which can be shortened to: Treat FUs others depend on as boards (with a special non-FD API the dependent part is connected to), but do not embed them in a flow in the diagram they are depended upon.   Attributes of Functional Units Creation and usage of functional units can be modified with attributes. So far the following have shown to be helpful: Singleton: FUs are by default multitons. FUs in the same of different flows with the same name refer to the same functionality, but to different instances. Think of functional units as objects that get instanciated anew whereever they appear in a design. Sometimes though it´s helpful to reuse the same instance of a functional unit; this is always due to valuable state it holds. Signify this by annotating the FU with a “(S)”. Multiton: FUs on which others depend are singletons by default. This is, because they usually are introduced where shared state comes into play. If you want to change them to be a singletons mark them with a “(M)”. Configurable: Some parts need to be configured before the can do they work in a flow. Annotate them with a “(C)” to have them initialized before any data items to be processed by them arrive. Do not assume any order in which FUs are configured. How such configuration is happening is an implementation detail. Entry point: In each design there needs to be a single part where “it all starts”. That´s the entry point for all processing. It´s like Program.Main() in C# programs. Mark the entry point part with an “(E)”. Quite often this will be the GUI part. How the entry point is started is an implementation detail. Just consider it the first FU to start do its job.   Patterns / Standard Parts If more than a single wire is attached to an output-pin that´s called a split (or fork). The same data is flowing on all of the wires. Remember: Flow-Designs are synchronous by default. So a split does not mean data is processed in parallel afterwards. Processing still happens synchronously and thus one branch after another. Do not assume any specific order of the processing on the different branches after the split.   It is common to do a split and let only parts of the original data flow on through the branches. This effectively means a map is needed after a split. This map can be implicit or explicit.   Although FUs can have multiple input-pins it is preferrable in most cases to combine input data from different branches using an explicit join: The default output of a join is a tuple of its input values. The default behavior of a join is to output a value whenever a new input is received. However, to produce its first output a join needs an input for all its input-pins. Other join behaviors can be: reset all inputs after an output only produce output if data arrives on certain input-pins

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• MVC's Html.DropDownList and "There is no ViewData item of type 'IEnumerable<SelectListItem>' that has the key '...'

  - by pjohnson

  ASP.NET MVC's HtmlHelper extension methods take out a lot of the HTML-by-hand drudgery to which MVC re-introduced us former WebForms programmers. Another thing to which MVC re-introduced us is poor documentation, after the excellent documentation for most of the rest of ASP.NET and the .NET Framework which I now realize I'd taken for granted. I'd come to regard using HtmlHelper methods instead of writing HTML by hand as a best practice. When I upgraded a project from MVC 3 to MVC 4, several hidden fields with boolean values broke, because MVC 3 called ToString() on those values implicitly, and MVC 4 threw an exception until you called ToString() explicitly. Fields that used HtmlHelper weren't affected. I then went through dozens of views and manually replaced hidden inputs that had been coded by hand with Html.Hidden calls. So for a dropdown list I was rendering on the initial page as empty, then populating via JavaScript after an AJAX call, I tried to use a HtmlHelper method: @Html.DropDownList("myDropdown") which threw an exception: System.InvalidOperationException: There is no ViewData item of type 'IEnumerable<SelectListItem>' that has the key 'myDropdown'. That's funny--I made no indication I wanted to use ViewData. Why was it looking there? Just render an empty select list for me. When I populated the list with items, it worked, but I didn't want to do that: @Html.DropDownList("myDropdown", new List<SelectListItem>() { new SelectListItem() { Text = "", Value = "" } }) I removed this dummy item in JavaScript after the AJAX call, so this worked fine, but I shouldn't have to give it a list with a dummy item when what I really want is an empty select. A bit of research with JetBrains dotPeek (helpfully recommended by Scott Hanselman) revealed the problem. Html.DropDownList requires some sort of data to render or it throws an error. The documentation hints at this but doesn't make it very clear. Behind the scenes, it checks if you've provided the DropDownList method any data. If you haven't, it looks in ViewData. If it's not there, you get the exception above. In my case, the helper wasn't doing much for me anyway, so I reverted to writing the HTML by hand (I ain't scared), and amended my best practice: When an HTML control has an associated HtmlHelper method and you're populating that control with data on the initial view, use the HtmlHelper method instead of writing by hand.

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• Silverlight Cream for November 08, 2011 -- #1165

  - by Dave Campbell

  In this Issue: Brian Noyes, Michael Crump, WindowsPhoneGeek, Erno de Weerd, Jesse Liberty, Derik Whittaker, Sumit Dutta, Asim Sajjad, Dhananjay Kumar, Kunal Chowdhury, and Beth Massi. Above the Fold: Silverlight: "Working with Prism 4 Part 1: Getting Started" Brian Noyes WP7: "Getting Started with the Coding4Fun toolkit Tile Control" WindowsPhoneGeek LightSwitch: "How to Connect to and Diagram your SQL Express Database in Visual Studio LightSwitch" Beth Massi Shoutouts: Michael Palermo's latest Desert Mountain Developers is up Michael Washington's latest Visual Studio #LightSwitch Daily is up From SilverlightCream.com: Working with Prism 4 Part 1: Getting Started Brian Noyes has a series starting at SilverlightShow about Prism 4 ... this is the first one, so a good time to jump in and pick up on an intro and basic info about Prism plus building your first Prism app. 10 Laps around Silverlight 5 (Part 5 of 10) Michael Crump has Part 5 of his 10-part Silverlight 5 investigation up at SilverlightShow talking about all the various text features added in Silverlight 5 Beta: Text Tracking and Leading, Linked and MultiColumn, OpenType, etc. Getting Started with the Coding4Fun toolkit Tile Control WindowsPhoneGeek takes on the Tile control from the Coding4Fun toolkit... as usual, great tutorial... diagrams, code, explanation Using AppHarbor, Bitbucket and Mercurial with ASP.NET and Silverlight – Part 2 CouchDB, Cloudant and Hammock Erno de Weerd has Part 2 of his trilogy and he's trying to beat David Anson for the long title record :) ... in this episode, he's adding in cloud storage to the mix in a 35-step tutorial. Background Audio Jesse Liberty's talking about background Audio... and no not the Muzak in the elevator (do they still have that?) ... he's tlking about the WP7.1 BackgroundAudioPlayer Using the ToggleSwitch in WinRT/Metro (for C#) Derik Whittaker shows off the ToggleSwitch for WinRT/Metro... not a lot to be said about it, but he says it all :) Part 19 - Windows Phone 7 - Access Phone Contacts Sumit Dutta has Part 19! of his WP7 series up... talking today about getting a phone number from the directory using the PhoneNumberChooserTask ContextMenu using MVVM Asim Sajjad shows how to make the Context Menu ViewModel friendly in this short tutorial. Code to make call in Windows Phone 7 Dhananjay Kumar's latest WP7 post is explaining how to make a call programmatically using the PhoneCallTask launcher. Silverlight Page Navigation Framework - Basic Concept Kunal Chowdhury has a 3-part tutorial series on Silverlight Navigation up. This is the first in the series, and he hits the basics... what constitutes a Page, and how to get started with the navigation framework. How to Connect to and Diagram your SQL Express Database in Visual Studio LightSwitch Beth Massi's latest LightSwitch post is on using the Data Designer to easily crete and model database tables... during development this is in SQL Express, but can be deployed to most SQL server db you like Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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• Minimal set of critical database operations

  - by Juan Carlos Coto

  In designing the data layer code for an application, I'm trying to determine if there is a minimal set of database operations (both single and combined) that are essential for proper application function (i.e. the database is left in an expected state after every data access call). Is there a way to determine the minimal set of database operations (functions, transactions, etc.) that are critical for an application to function correctly? How do I find it? Thanks very much!

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• Making the Case for Centralized WLAN Management

  With just one vendor to call and one bill to pay, Charlie Schluting argues that managing a WLAN with central controllers is the way to go, and explains how that works with Cisco gear.

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• Setting up Visual Studio 2010 to step into Microsoft .NET Source Code

  - by rajbk

  Using the Microsoft Symbol Server to obtain symbol debugging information is now much easier in VS 2010. Microsoft gives you access to their internet symbol server that contains symbol files for most of the .NET framework including the recently announced availability of MVC 2 Symbols.  SETUP In VS 2010 RTM, go to Tools –> Options –> Debugging –> General. Check “Enable .NET Framework source stepping” We get the following dialog box   This automatically disables “Enable My Code”   Go to Debugging –> Symbols and Check “Microsoft Symbol Servers”. You can selectively exclude modules if you want to.   You will get a warning dialog like so: Hitting OK will start the download process   The setup is complete. You are now ready to start debugging! DEBUGGING Add a break point to your application and run the application in debug mode (F5 shortcut for me). Go to your call stack when you hit the break point. Right click on a frame that is grayed out. Select “Load Symbols from” “Microsoft Symbol Servers”. VS will begin a one time download of that assembly. This assembly will be cached locally so you don’t have to wait for the download the next time you debug the app.   We get a one time license agreement dialog box You might see an error like the one below regarding different encoding (hopefully will be fixed).    Assemblies for which the symbols have been loaded are no longer grayed out. Double clicking on any entry in the call stack should now directly take you to the source code for that assembly. AFAIK, not all symbols are available on the MS symbol server. In cases like that you will see a tab like the one below and be given the option to “Show Disassembly”. Enjoy! Newsreel Announcer: Humiliated, Muntz vows a return to Paradise Falls and promises to capture the beast alive! Charles Muntz: [speaking to a large audience outside in the newsreel] I promise to capture the beast alive, and I will not come back until I do!

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• UppercuT &ndash; Custom Extensions Now With PowerShell and Ruby

  - by Robz / Fervent Coder

  Arguably, one of the most powerful features of UppercuT (UC) is the ability to extend any step of the build process with a pre, post, or replace hook. This customization is done in a separate location from the build so you can upgrade without wondering if you broke the build. There is a hook before each step of the build has run. There is a hook after. And back to power again, there is a replacement hook. If you don’t like what the step is doing and/or you want to replace it’s entire functionality, you just drop a custom replacement extension and UppercuT will perform the custom step instead. Up until recently all custom hooks had to be written in NAnt. Now they are a little sweeter because you no longer need to use NAnt to extend UC if you don’t want to. You can use PowerShell. Or Ruby.   Let that sink in for a moment. You don’t have to even need to interact with NAnt at all now. Extension Points On the wiki, all of the extension points are shown. The basic idea is that you would put whatever customization you are doing in a separate folder named build.custom. Each step Let’s take a look at all we can customize: The start point is default.build. It calls build.custom/default.pre.build if it exists, then it runs build/default.build (normal tasks) OR build.custom/default.replace.build if it exists, and finally build.custom/default.post.build if it exists. Every step below runs with the same extension points but changes on the file name it is looking for. NOTE: If you include default.replace.build, nothing else will run because everything is called from default.build.    * policyChecks.step    * versionBuilder.step NOTE: If you include build.custom/versionBuilder.replace.step, the items below will not run.      - svn.step, tfs.step, or git.step (the custom tasks for these need to go in build.custom/versioners)    * generateBuildInfo.step    * compile.step    * environmentBuilder.step    * analyze.step NOTE: If you include build.custom/analyze.replace.step, the items below will not run.      - test.step (the custom tasks for this need to go in build.custom/analyzers) NOTE: If you include build.custom/analyzers/test.replace.step, the items below will not run.        + mbunit2.step, gallio.step, or nunit.step (the custom tasks for these need to go in build.custom/analyzers)      - ncover.step (the custom tasks for this need to go in build.custom/analyzers)      - ndepend.step (the custom tasks for this need to go in build.custom/analyzers)      - moma.step (the custom tasks for this need to go in build.custom/analyzers)    * package.step NOTE: If you include build.custom/package.replace.step, the items below will not run.      - deploymentBuilder.step Customize UppercuT Builds With PowerShell UppercuT can now be extended with PowerShell (PS). To customize any extension point with PS, just add .ps1 to the end of the file name and write your custom tasks in PowerShell. If you are not signing your scripts you will need to change a setting in the UppercuT.config file. This does impose a security risk, because this allows PS to now run any PS script. This setting stays that way on ANY machine that runs the build until manually changed by someone. I’m not responsible if you mess up your machine or anyone else’s by doing this. You’ve been warned. Now that you are fully aware of any security holes you may open and are okay with that, let’s move on. Let’s create a file called default.replace.build.ps1 in the build.custom folder. Open that file in notepad and let’s add this to it: write-host "hello - I'm a custom task written in Powershell!" Now, let’s run build.bat. You could get some PSake action going here. I won’t dive into that in this post though. Customize UppercuT Builds With Ruby If you want to customize any extension point with Ruby, just add .rb to the end of the file name and write your custom tasks in Ruby.  Let’s write a custom ruby task for UC. If you were thinking it would be the same as the one we just wrote for PS, you’d be right! In the build.custom folder, lets create a file called default.replace.build.rb. Open that file in notepad and let’s put this in there: puts "I'm a custom ruby task!" Now, let’s run build.bat again. That’s chunky bacon. UppercuT and Albacore.NET Just for fun, I wanted to see if I could replace the compile.step with a Rake task. Not just any rake task, Albacore’s msbuild task. Albacore is a suite of rake tasks brought about by Derick Bailey to make building .NET with Rake easier. It has quite a bit of support with developers that are using Rake to build code. In my build.custom folder, I drop a compile.replace.step.rb. I also put in a separate file that will contain my Albacore rake task and I call that compile.rb. What are the contents of compile.replace.step.rb? rake = 'rake' arguments= '-f ' + Dir.pwd + '/../build.custom/compile.rb' #puts "Calling #{rake} " + arguments system("#{rake} " + arguments) Since the custom extensions call ruby, we have to shell back out and call rake. That’s what we are doing here. We also realize that ruby is called from the build folder, so we need to back out and dive into the build.custom folder to find the file that is technically next to us. What are the contents of compile.rb? require 'rubygems' require 'fileutils' require 'albacore' task :default => [:compile] puts "Using Ruby to compile UppercuT with Albacore Tasks" desc 'Compile the source' msbuild :compile do |msb| msb.properties = { :configuration => :Release, :outputpath => '../../build_output/UppercuT' } msb.targets [:clean, :build] msb.verbosity = "quiet" msb.path_to_command = 'c:/Windows/Microsoft.NET/Framework/v3.5/MSBuild.exe' msb.solution = '../uppercut.sln' end We are using the msbuild task here. We change the output path to the build_output/UppercuT folder. The output path has “../../” because this is based on every project. We could grab the current directory and then point the task specifically to a folder if we have projects that are at different levels. We want the verbosity to be quiet so we set that as well. So what kind of output do you get for this? Let’s run build.bat custom_tasks_replace:      [echo] Running custom tasks instead of normal tasks if C:\code\uppercut\build\..\build.custom\compile.replace.step exists.      [exec] (in C:/code/uppercut/build)      [exec] Using Ruby to compile UppercuT with Albacore Tasks      [exec] Microsoft (R) Build Engine Version 3.5.30729.4926      [exec] [Microsoft .NET Framework, Version 2.0.50727.4927]      [exec] Copyright (C) Microsoft Corporation 2007. All rights reserved. If you think this is awesome, you’d be right!   With this knowledge you shall build.

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• Web Platform Installer 2.0 and Visual Studio Web Developer 2010 Express

  - by Latest Microsoft Blogs

  I was setting up a new machine for presentations and I was getting ready to install Visual Studio 2010 Express   and figured I'd go see if the Web Platform Installer (we call it "Web-P-I") had the new versions of VS2010 ready to go Read More......(read more)

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• Oracle SOA Security for OUAF Web Services

  - by Anthony Shorten

  With the ability to use Oracle SOA Suite 11g with the Oracle Utilities Application Framework based products, an additional consideration needs to be configured to ensure correct integration. That additional consideration is security. By default, SOA Suite propagates any credentials from the calling application through to the interfacing applications. In most cases, this behavior is not appropriate as the calling application may use different credential stores and also some interfaces are “disconnected” from a calling application (for example, a file based load using the File Adapter). These situations require that the Web Service calls to the Oracle Utilities Application Framework based products have their own valid credentials. To do this the credentials must be attached at design time or at run time to provide the necessary credentials for the call. There are a number of techniques that can be used to do this: At design time, when integrating a Web Service from an Oracle Utilities Application Framework based product you can attach the security policy “oracle/wss_username_token_client_policy” in the composite.xml view. In this view select the Web Service you want to attach the policy to and right click to display the context menu and select “Configure WS Policies” and select the above policy from the list. If you are using SSL then you can use “oracle/wss_username_token_over_ssl_client_policy” instead. At design time, you can also specify the credential key (csf-key) associated with the above policy by selecting the policy and clicking “Edit Config Override Properties”. You name the key appropriately. Everytime the SOA components are deployed the credential configuration is also sent. You can also do this after deployment, or what I call at “runtime”, by specifying the policy and credential key in the Fusion Middleware Control. Refer to the Fusion Middleware Control documentation on how to do this. To complete the configuration you need to add a map and the key specified earlier to the credential store in the Oracle WebLogic instance used for Oracle SOA Suite. From Fusion Middleware Control, you do this by selecting the domain the SOA Suite is installed in a select “Credentials” from the context menu. You now need to add the credentials by adding the map “oracle.wsm.security” (the name is IMPORTANT) and creating a key with the necessary valid credentials. The example below added a key called “mdm.key”. The name I used is for example only. You can name the key anything you like as long as it corresponds to the key you specified in the design time component. Note: I used SYSUSER as an example credentials in the example, in real life you would use another credential as SYSUSER is not appropriate for production use. This key can be reused for other Oracle Utilities Application Framework Web Service integrations or you can use other keys for individual Web Service calls. Once the key is created and the SOA Suite components deployed the transactions should be able to be called as necessary. If you need to change the password for the credentials it can be done using the Fusion Middleware Control functionality.

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• ASP.NET MVC 2 throws exception for ‘favicon.ico’

  - by nmarun

  I must be on fire or something – third blog in 2 days… awesome! Before I begin, in case you’re wondering, favicon.ico is the small image that appears to the left of your web address, once the page loads. In order to learn more about MVC or any thing for that matter, it’s better to look at the source itself. Since MVC is open source (at least some part of it is), I started looking at the source code that’s available for download. While doing so, I hit Steve Sanderson’s blog site where he explains in great detail the way to debug your app using ASP.NET MVC source code. For those who are not aware, Steve Sanderson’s book - Pro ASP.NET MVC Framework, is one of the best books to learn about MVC. Alrighty, I followed the article and I hit F5 to debug the default / unchanged MVC project. I put a breakpoint in the DefaultControllerFactory.cs, CreateController() method. To know a little more about this class and the method, read this. Sure enough, the control stopped at the breakpoint and I hit F5 again and the page rendered just fine. But then what’s this? The breakpoint was hit again, as if something else was being requested. I now hovered my mouse over the ‘controllerName’ parameter and it says – favicon.ico. This by itself was more than enough for me to raise my eye-brows, but what happened next just took the ground below my feet. Oh, oh, I’m sorry I’m just typing, no code, no image, so here are a couple of screen captures. The first one shows the request for the Home controller; I get ‘Home’ when I hover over the parameter: And here’s the one that shows the same for call for ‘favicon.ico’. So, I step through the code and when the control reaches line 91 – GetControllerInstance() method, I step in. This is when I had the ‘ground-losing’ experience. Wow, an exception is being thrown for this file and that too in RTM. For some reason MVC thinks, this as a controller and tries to run it through the MvcHandler and it hits this snag. So it seems like this will happen for any MVC 2 site and this did not happen for me in the previous version of MVC. Before I get to how to resolve it, here’s another way of reproducing this exception. Revert back all your changes that you did as mentioned in Steve’s blog above. Now, add a class to your MVC project and call it say, MyControllerFactory and let this inherit from DefaultControllerFactory class. (Read this for details on the DefaultControllerFactory class is and how it is used in a different context). Add an override for the CreateController() method and for the sake of this blog, just copy the same content from the DefaultControllerFactory class. The last step is to tell your MVC app to use the MyControllerFactory class instead of the default one. To do this, go to your Global.asax.cs file and add line 6 of the snippet below: 1: protected void Application_Start() 2: { 3: AreaRegistration.RegisterAllAreas(); 4:   5: RegisterRoutes(RouteTable.Routes); 6: ControllerBuilder.Current.SetControllerFactory(new MyControllerFactory()); 7: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now, you’re ready to reproduce the issue. Just F5 the project and when you hit the overridden CreateController() method for the second time, this is what it looks like for me: And continuing further gives me the same exception. I believe this is something that MS should fix, as not having ‘favicon.ico’ file will be common for most of the applications. So I think the when you create an MVC project, line 6 should be added by default by Visual Studio itself: 1: public class MvcApplication : System.Web.HttpApplication 2: { 3: public static void RegisterRoutes(RouteCollection routes) 4: { 5: routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); 6: routes.IgnoreRoute("favicon.ico"); 7:   8: routes.MapRoute( 9: "Default", // Route name 10: "{controller}/{action}/{id}", // URL with parameters 11: new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults 12: ); 13: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } There it is, that’s the solution to avoid the exception altogether. I tried this both IE8 and Firefox browsers and was able to successfully reproduce the error. Hope someone will look at this issue and find a fix. Just before I finish up, I found another ‘bug’, if you want to call it, with Visual Studio 2008. Remember how you could change what browser you want your application to run in by just right clicking on the .aspx file and choosing ‘Browse with…’? Seems like that’s missing when you’re working with an MVC project. In order to test the above bug in the other browser, I had to load a classic ASP.NET project, change the settings and then run my MVC project. Felt kinda ‘icky’, for lack of a better word.

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• Novell's Motion to Allow Evidence: SCO Opened the Door

  <b>Groklaw:</b> "SCO's attorney Stuart Singer may have gotten carried away with his theatrical indignation. And when a party slips like this, what lawyers call opening the door, it can indeed have consequences. Novell was just waiting for a moment like this."

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• SQLAuthority News MS Access Database is the Way to Go April 1st Humor

  First of all, today is April 1- April Fools Day, so I have written this post for some light entertainment. My friend has just sent me an email about why a person should go for Access Database. For a short background, I used to be an MS Access user once (I will not call myself [...]...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Google I/O 2012 - The Sensitive Side of Android

  Google I/O 2012 - The Sensitive Side of Android Tony Chan, Ankur Kotwal , Tim Bray, Tony Chan Android has a sensitive side. In this session, we will call out all the Android sensors: accelerometer, gyroscope, light, and more. We'll cover best practices for handling sensor data, with special focus on balancing battery life and usability. For all I/O 2012 sessions, go to developers.google.com From: GoogleDevelopers Views: 2157 35 ratings Time: 56:06 More in Science & Technology

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• Windows Azure Service Bus Splitter and Aggregator

  - by Alan Smith

  This article will cover basic implementations of the Splitter and Aggregator patterns using the Windows Azure Service Bus. The content will be included in the next release of the “Windows Azure Service Bus Developer Guide”, along with some other patterns I am working on. I’ve taken the pattern descriptions from the book “Enterprise Integration Patterns” by Gregor Hohpe. I bought a copy of the book in 2004, and recently dusted it off when I started to look at implementing the patterns on the Windows Azure Service Bus. Gregor has also presented an session in 2011 “Enterprise Integration Patterns: Past, Present and Future” which is well worth a look. I’ll be covering more patterns in the coming weeks, I’m currently working on Wire-Tap and Scatter-Gather. There will no doubt be a section on implementing these patterns in my “SOA, Connectivity and Integration using the Windows Azure Service Bus” course. There are a number of scenarios where a message needs to be divided into a number of sub messages, and also where a number of sub messages need to be combined to form one message. The splitter and aggregator patterns provide a definition of how this can be achieved. This section will focus on the implementation of basic splitter and aggregator patens using the Windows Azure Service Bus direct programming model. In BizTalk Server receive pipelines are typically used to implement the splitter patterns, with sequential convoy orchestrations often used to aggregate messages. In the current release of the Service Bus, there is no functionality in the direct programming model that implements these patterns, so it is up to the developer to implement them in the applications that send and receive messages. Splitter A message splitter takes a message and spits the message into a number of sub messages. As there are different scenarios for how a message can be split into sub messages, message splitters are implemented using different algorithms. The Enterprise Integration Patterns book describes the splatter pattern as follows: How can we process a message if it contains multiple elements, each of which may have to be processed in a different way? Use a Splitter to break out the composite message into a series of individual messages, each containing data related to one item. The Enterprise Integration Patterns website provides a description of the Splitter pattern here. In some scenarios a batch message could be split into the sub messages that are contained in the batch. The splitting of a message could be based on the message type of sub-message, or the trading partner that the sub message is to be sent to. Aggregator An aggregator takes a stream or related messages and combines them together to form one message. The Enterprise Integration Patterns book describes the aggregator pattern as follows: How do we combine the results of individual, but related messages so that they can be processed as a whole? Use a stateful filter, an Aggregator, to collect and store individual messages until a complete set of related messages has been received. Then, the Aggregator publishes a single message distilled from the individual messages. The Enterprise Integration Patterns website provides a description of the Aggregator pattern here. A common example of the need for an aggregator is in scenarios where a stream of messages needs to be combined into a daily batch to be sent to a legacy line-of-business application. The BizTalk Server EDI functionality provides support for batching messages in this way using a sequential convoy orchestration. Scenario The scenario for this implementation of the splitter and aggregator patterns is the sending and receiving of large messages using a Service Bus queue. In the current release, the Windows Azure Service Bus currently supports a maximum message size of 256 KB, with a maximum header size of 64 KB. This leaves a safe maximum body size of 192 KB. The BrokeredMessage class will support messages larger than 256 KB; in fact the Size property is of type long, implying that very large messages may be supported at some point in the future. The 256 KB size restriction is set in the service bus components that are deployed in the Windows Azure data centers. One of the ways of working around this size restriction is to split large messages into a sequence of smaller sub messages in the sending application, send them via a queue, and then reassemble them in the receiving application. This scenario will be used to demonstrate the pattern implementations. Implementation The splitter and aggregator will be used to provide functionality to send and receive large messages over the Windows Azure Service Bus. In order to make the implementations generic and reusable they will be implemented as a class library. The splitter will be implemented in the LargeMessageSender class and the aggregator in the LargeMessageReceiver class. A class diagram showing the two classes is shown below. Implementing the Splitter The splitter will take a large brokered message, and split the messages into a sequence of smaller sub-messages that can be transmitted over the service bus messaging entities. The LargeMessageSender class provides a Send method that takes a large brokered message as a parameter. The implementation of the class is shown below; console output has been added to provide details of the splitting operation. public class LargeMessageSender {     private static int SubMessageBodySize = 192 * 1024;     private QueueClient m_QueueClient;       public LargeMessageSender(QueueClient queueClient)     {         m_QueueClient = queueClient;     }       public void Send(BrokeredMessage message)     {         // Calculate the number of sub messages required.         long messageBodySize = message.Size;         int nrSubMessages = (int)(messageBodySize / SubMessageBodySize);         if (messageBodySize % SubMessageBodySize != 0)         {             nrSubMessages++;         }           // Create a unique session Id.         string sessionId = Guid.NewGuid().ToString();         Console.WriteLine("Message session Id: " + sessionId);         Console.Write("Sending {0} sub-messages", nrSubMessages);           Stream bodyStream = message.GetBody<Stream>();         for (int streamOffest = 0; streamOffest < messageBodySize;             streamOffest += SubMessageBodySize)         {                                     // Get the stream chunk from the large message             long arraySize = (messageBodySize - streamOffest) > SubMessageBodySize                 ? SubMessageBodySize : messageBodySize - streamOffest;             byte[] subMessageBytes = new byte[arraySize];             int result = bodyStream.Read(subMessageBytes, 0, (int)arraySize);             MemoryStream subMessageStream = new MemoryStream(subMessageBytes);               // Create a new message             BrokeredMessage subMessage = new BrokeredMessage(subMessageStream, true);             subMessage.SessionId = sessionId;               // Send the message             m_QueueClient.Send(subMessage);             Console.Write(".");         }         Console.WriteLine("Done!");     }} The LargeMessageSender class is initialized with a QueueClient that is created by the sending application. When the large message is sent, the number of sub messages is calculated based on the size of the body of the large message. A unique session Id is created to allow the sub messages to be sent as a message session, this session Id will be used for correlation in the aggregator. A for loop in then used to create the sequence of sub messages by creating chunks of data from the stream of the large message. The sub messages are then sent to the queue using the QueueClient. As sessions are used to correlate the messages, the queue used for message exchange must be created with the RequiresSession property set to true. Implementing the Aggregator The aggregator will receive the sub messages in the message session that was created by the splitter, and combine them to form a single, large message. The aggregator is implemented in the LargeMessageReceiver class, with a Receive method that returns a BrokeredMessage. The implementation of the class is shown below; console output has been added to provide details of the splitting operation.   public class LargeMessageReceiver {     private QueueClient m_QueueClient;       public LargeMessageReceiver(QueueClient queueClient)     {         m_QueueClient = queueClient;     }       public BrokeredMessage Receive()     {         // Create a memory stream to store the large message body.         MemoryStream largeMessageStream = new MemoryStream();           // Accept a message session from the queue.         MessageSession session = m_QueueClient.AcceptMessageSession();         Console.WriteLine("Message session Id: " + session.SessionId);         Console.Write("Receiving sub messages");           while (true)         {             // Receive a sub message             BrokeredMessage subMessage = session.Receive(TimeSpan.FromSeconds(5));               if (subMessage != null)             {                 // Copy the sub message body to the large message stream.                 Stream subMessageStream = subMessage.GetBody<Stream>();                 subMessageStream.CopyTo(largeMessageStream);                   // Mark the message as complete.                 subMessage.Complete();                 Console.Write(".");             }             else             {                 // The last message in the sequence is our completeness criteria.                 Console.WriteLine("Done!");                 break;             }         }                     // Create an aggregated message from the large message stream.         BrokeredMessage largeMessage = new BrokeredMessage(largeMessageStream, true);         return largeMessage;     } }   The LargeMessageReceiver initialized using a QueueClient that is created by the receiving application. The receive method creates a memory stream that will be used to aggregate the large message body. The AcceptMessageSession method on the QueueClient is then called, which will wait for the first message in a message session to become available on the queue. As the AcceptMessageSession can throw a timeout exception if no message is available on the queue after 60 seconds, a real-world implementation should handle this accordingly. Once the message session as accepted, the sub messages in the session are received, and their message body streams copied to the memory stream. Once all the messages have been received, the memory stream is used to create a large message, that is then returned to the receiving application. Testing the Implementation The splitter and aggregator are tested by creating a message sender and message receiver application. The payload for the large message will be one of the webcast video files from http://www.cloudcasts.net/, the file size is 9,697 KB, well over the 256 KB threshold imposed by the Service Bus. As the splitter and aggregator are implemented in a separate class library, the code used in the sender and receiver console is fairly basic. The implementation of the main method of the sending application is shown below.   static void Main(string[] args) {     // Create a token provider with the relevant credentials.     TokenProvider credentials =         TokenProvider.CreateSharedSecretTokenProvider         (AccountDetails.Name, AccountDetails.Key);       // Create a URI for the serivce bus.     Uri serviceBusUri = ServiceBusEnvironment.CreateServiceUri         ("sb", AccountDetails.Namespace, string.Empty);       // Create the MessagingFactory     MessagingFactory factory = MessagingFactory.Create(serviceBusUri, credentials);       // Use the MessagingFactory to create a queue client     QueueClient queueClient = factory.CreateQueueClient(AccountDetails.QueueName);       // Open the input file.     FileStream fileStream = new FileStream(AccountDetails.TestFile, FileMode.Open);       // Create a BrokeredMessage for the file.     BrokeredMessage largeMessage = new BrokeredMessage(fileStream, true);       Console.WriteLine("Sending: " + AccountDetails.TestFile);     Console.WriteLine("Message body size: " + largeMessage.Size);     Console.WriteLine();         // Send the message with a LargeMessageSender     LargeMessageSender sender = new LargeMessageSender(queueClient);     sender.Send(largeMessage);       // Close the messaging facory.     factory.Close();  } The implementation of the main method of the receiving application is shown below. static void Main(string[] args) {       // Create a token provider with the relevant credentials.     TokenProvider credentials =         TokenProvider.CreateSharedSecretTokenProvider         (AccountDetails.Name, AccountDetails.Key);       // Create a URI for the serivce bus.     Uri serviceBusUri = ServiceBusEnvironment.CreateServiceUri         ("sb", AccountDetails.Namespace, string.Empty);       // Create the MessagingFactory     MessagingFactory factory = MessagingFactory.Create(serviceBusUri, credentials);       // Use the MessagingFactory to create a queue client     QueueClient queueClient = factory.CreateQueueClient(AccountDetails.QueueName);       // Create a LargeMessageReceiver and receive the message.     LargeMessageReceiver receiver = new LargeMessageReceiver(queueClient);     BrokeredMessage largeMessage = receiver.Receive();       Console.WriteLine("Received message");     Console.WriteLine("Message body size: " + largeMessage.Size);       string testFile = AccountDetails.TestFile.Replace(@"\In\", @"\Out\");     Console.WriteLine("Saving file: " + testFile);       // Save the message body as a file.     Stream largeMessageStream = largeMessage.GetBody<Stream>();     largeMessageStream.Seek(0, SeekOrigin.Begin);     FileStream fileOut = new FileStream(testFile, FileMode.Create);     largeMessageStream.CopyTo(fileOut);     fileOut.Close();       Console.WriteLine("Done!"); } In order to test the application, the sending application is executed, which will use the LargeMessageSender class to split the message and place it on the queue. The output of the sender console is shown below. The console shows that the body size of the large message was 9,929,365 bytes, and the message was sent as a sequence of 51 sub messages. When the receiving application is executed the results are shown below. The console application shows that the aggregator has received the 51 messages from the message sequence that was creating in the sending application. The messages have been aggregated to form a massage with a body of 9,929,365 bytes, which is the same as the original large message. The message body is then saved as a file. Improvements to the Implementation The splitter and aggregator patterns in this implementation were created in order to show the usage of the patterns in a demo, which they do quite well. When implementing these patterns in a real-world scenario there are a number of improvements that could be made to the design. Copying Message Header Properties When sending a large message using these classes, it would be great if the message header properties in the message that was received were copied from the message that was sent. The sending application may well add information to the message context that will be required in the receiving application. When the sub messages are created in the splitter, the header properties in the first message could be set to the values in the original large message. The aggregator could then used the values from this first sub message to set the properties in the message header of the large message during the aggregation process. Using Asynchronous Methods The current implementation uses the synchronous send and receive methods of the QueueClient class. It would be much more performant to use the asynchronous methods, however doing so may well affect the sequence in which the sub messages are enqueued, which would require the implementation of a resequencer in the aggregator to restore the correct message sequence. Handling Exceptions In order to keep the code readable no exception handling was added to the implementations. In a real-world scenario exceptions should be handled accordingly.

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• Compute Scalars, Expressions and Execution Plan Performance

  - by Paul White

  The humble Compute Scalar is one of the least well-understood of the execution plan operators, and usually the last place people look for query performance problems. It often appears in execution plans with a very low (or even zero) cost, which goes some way to explaining why people ignore it. Some readers will already know that a Compute Scalar can contain a call to a user-defined function, and that any T-SQL function with a BEGIN…END block in its definition can have truly disastrous consequences...(read more)

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• How to submit a form on pressing enter key

  - by SAMIR BHOGAYTA

  function clickButton(e, buttonid) { var bt = document.getElementById(buttonid); if (typeof bt == 'object'){ if(navigator.appName.indexOf("Netscape")(-1)){ if (e.keyCode == 13){ bt.click(); return false; } } if (navigator.appName.indexOf("Microsoft Internet Explorer")(-1)) { if (event.keyCode == 13){ bt.click(); return false; } } } } //Call this function on last text box of a form with onKeyPress="clickButton(this)"

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• Consistent Flash Player Crash ONLY on YouTube

  - by Aiman Mueller

  It could be similar to one of the bugs listed on LaunchPad (#689158), but may not be. Basically, I used to occasionally get a crash on YouTube and opening a new browser or rebooting (don't remember which) took care of the problem. However, now, EVERY time I try to open a video on YouTube, I get the frowning block and the message, "The Adobe Flash plugin has crashed." However, Hulu would also call for Adobe, right? But I can see videos there.

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• Much Ado About Nothing: Stub Objects

  - by user9154181

  The Solaris 11 link-editor (ld) contains support for a new type of object that we call a stub object. A stub object is a shared object, built entirely from mapfiles, that supplies the same linking interface as the real object, while containing no code or data. Stub objects cannot be executed — the runtime linker will kill any process that attempts to load one. However, you can link to a stub object as a dependency, allowing the stub to act as a proxy for the real version of the object. You may well wonder if there is a point to producing an object that contains nothing but linking interface. As it turns out, stub objects are very useful for building large bodies of code such as Solaris. In the last year, we've had considerable success in applying them to one of our oldest and thorniest build problems. In this discussion, I will describe how we came to invent these objects, and how we apply them to building Solaris. This posting explains where the idea for stub objects came from, and details our long and twisty journey from hallway idea to standard link-editor feature. I expect that these details are mainly of interest to those who work on Solaris and its makefiles, those who have done so in the past, and those who work with other similar bodies of code. A subsequent posting will omit the history and background details, and instead discuss how to build and use stub objects. If you are mainly interested in what stub objects are, and don't care about the underlying software war stories, I encourage you to skip ahead. The Long Road To Stubs This all started for me with an email discussion in May of 2008, regarding a change request that was filed in 2002, entitled: 4631488 lib/Makefile is too patient: .WAITs should be reduced This CR encapsulates a number of cronic issues with Solaris builds: We build Solaris with a parallel make (dmake) that tries to build as much of the code base in parallel as possible. There is a lot of code to build, and we've long made use of parallelized builds to get the job done quicker. This is even more important in today's world of massively multicore hardware. Solaris contains a large number of executables and shared objects. Executables depend on shared objects, and shared objects can depend on each other. Before you can build an object, you need to ensure that the objects it needs have been built. This implies a need for serialization, which is in direct opposition to the desire to build everying in parallel. To accurately build objects in the right order requires an accurate set of make rules defining the things that depend on each other. This sounds simple, but the reality is quite complex. In practice, having programmers explicitly specify these dependencies is a losing strategy: It's really hard to get right. It's really easy to get it wrong and never know it because things build anyway. Even if you get it right, it won't stay that way, because dependencies between objects can change over time, and make cannot help you detect such drifing. You won't know that you got it wrong until the builds break. That can be a long time after the change that triggered the breakage happened, making it hard to connect the cause and the effect. Usually this happens just before a release, when the pressure is on, its hard to think calmly, and there is no time for deep fixes. As a poor compromise, the libraries in core Solaris were built using a set of grossly incomplete hand written rules, supplemented with a number of dmake .WAIT directives used to group the libraries into sets of non-interacting groups that can be built in parallel because we think they don't depend on each other. From time to time, someone will suggest that we could analyze the built objects themselves to determine their dependencies and then generate make rules based on those relationships. This is possible, but but there are complications that limit the usefulness of that approach: To analyze an object, you have to build it first. This is a classic chicken and egg scenario. You could analyze the results of a previous build, but then you're not necessarily going to get accurate rules for the current code. It should be possible to build the code without having a built workspace available. The analysis will take time, and remember that we're constantly trying to make builds faster, not slower. By definition, such an approach will always be approximate, and therefore only incremantally more accurate than the hand written rules described above. The hand written rules are fast and cheap, while this idea is slow and complex, so we stayed with the hand written approach. Solaris was built that way, essentially forever, because these are genuinely difficult problems that had no easy answer. The makefiles were full of build races in which the right outcomes happened reliably for years until a new machine or a change in build server workload upset the accidental balance of things. After figuring out what had happened, you'd mutter "How did that ever work?", add another incomplete and soon to be inaccurate make dependency rule to the system, and move on. This was not a satisfying solution, as we tend to be perfectionists in the Solaris group, but we didn't have a better answer. It worked well enough, approximately. And so it went for years. We needed a different approach — a new idea to cut the Gordian Knot. In that discussion from May 2008, my fellow linker-alien Rod Evans had the initial spark that lead us to a game changing series of realizations: The link-editor is used to link objects together, but it only uses the ELF metadata in the object, consisting of symbol tables, ELF versioning sections, and similar data. Notably, it does not look at, or understand, the machine code that makes an object useful at runtime. If you had an object that only contained the ELF metadata for a dependency, but not the code or data, the link-editor would find it equally useful for linking, and would never know the difference. Call it a stub object. In the core Solaris OS, we require all objects to be built with a link-editor mapfile that describes all of its publically available functions and data. Could we build a stub object using the mapfile for the real object? It ought to be very fast to build stub objects, as there are no input objects to process. Unlike the real object, stub objects would not actually require any dependencies, and so, all of the stubs for the entire system could be built in parallel. When building the real objects, one could link against the stub objects instead of the real dependencies. This means that all the real objects can be built built in parallel too, without any serialization. We could replace a system that requires perfect makefile rules with a system that requires no ordering rules whatsoever. The results would be considerably more robust. We immediately realized that this idea had potential, but also that there were many details to sort out, lots of work to do, and that perhaps it wouldn't really pan out. As is often the case, it would be necessary to do the work and see how it turned out. Following that conversation, I set about trying to build a stub object. We determined that a faithful stub has to do the following: Present the same set of global symbols, with the same ELF versioning, as the real object. Functions are simple — it suffices to have a symbol of the right type, possibly, but not necessarily, referencing a null function in its text segment. Copy relocations make data more complicated to stub. The possibility of a copy relocation means that when you create a stub, the data symbols must have the actual size of the real data. Any error in this will go uncaught at link time, and will cause tragic failures at runtime that are very hard to diagnose. For reasons too obscure to go into here, involving tentative symbols, it is also important that the data reside in bss, or not, matching its placement in the real object. If the real object has more than one symbol pointing at the same data item, we call these aliased symbols. All data symbols in the stub object must exhibit the same aliasing as the real object. We imagined the stub library feature working as follows: A command line option to ld tells it to produce a stub rather than a real object. In this mode, only mapfiles are examined, and any object or shared libraries on the command line are are ignored. The extra information needed (function or data, size, and bss details) would be added to the mapfile. When building the real object instead of the stub, the extra information for building stubs would be validated against the resulting object to ensure that they match. In exploring these ideas, I immediately run headfirst into the reality of the original mapfile syntax, a subject that I would later write about as The Problem(s) With Solaris SVR4 Link-Editor Mapfiles. The idea of extending that poor language was a non-starter. Until a better mapfile syntax became available, which seemed unlikely in 2008, the solution could not involve extentions to the mapfile syntax. Instead, we cooked up the idea (hack) of augmenting mapfiles with stylized comments that would carry the necessary information. A typical definition might look like: # DATA(i386) __iob 0x3c0 # DATA(amd64,sparcv9) __iob 0xa00 # DATA(sparc) __iob 0x140 iob; A further problem then became clear: If we can't extend the mapfile syntax, then there's no good way to extend ld with an option to produce stub objects, and to validate them against the real objects. The idea of having ld read comments in a mapfile and parse them for content is an unacceptable hack. The entire point of comments is that they are strictly for the human reader, and explicitly ignored by the tool. Taking all of these speed bumps into account, I made a new plan: A perl script reads the mapfiles, generates some small C glue code to produce empty functions and data definitions, compiles and links the stub object from the generated glue code, and then deletes the generated glue code. Another perl script used after both objects have been built, to compare the real and stub objects, using data from elfdump, and validate that they present the same linking interface. By June 2008, I had written the above, and generated a stub object for libc. It was a useful prototype process to go through, and it allowed me to explore the ideas at a deep level. Ultimately though, the result was unsatisfactory as a basis for real product. There were so many issues: The use of stylized comments were fine for a prototype, but not close to professional enough for shipping product. The idea of having to document and support it was a large concern. The ideal solution for stub objects really does involve having the link-editor accept the same arguments used to build the real object, augmented with a single extra command line option. Any other solution, such as our prototype script, will require makefiles to be modified in deeper ways to support building stubs, and so, will raise barriers to converting existing code. A validation script that rederives what the linker knew when it built an object will always be at a disadvantage relative to the actual linker that did the work. A stub object should be identifyable as such. In the prototype, there was no tag or other metadata that would let you know that they weren't real objects. Being able to identify a stub object in this way means that the file command can tell you what it is, and that the runtime linker can refuse to try and run a program that loads one. At that point, we needed to apply this prototype to building Solaris. As you might imagine, the task of modifying all the makefiles in the core Solaris code base in order to do this is a massive task, and not something you'd enter into lightly. The quality of the prototype just wasn't good enough to justify that sort of time commitment, so I tabled the project, putting it on my list of long term things to think about, and moved on to other work. It would sit there for a couple of years. Semi-coincidentally, one of the projects I tacked after that was to create a new mapfile syntax for the Solaris link-editor. We had wanted to do something about the old mapfile syntax for many years. Others before me had done some paper designs, and a great deal of thought had already gone into the features it should, and should not have, but for various reasons things had never moved beyond the idea stage. When I joined Sun in late 2005, I got involved in reviewing those things and thinking about the problem. Now in 2008, fresh from relearning for the Nth time why the old mapfile syntax was a huge impediment to linker progress, it seemed like the right time to tackle the mapfile issue. Paving the way for proper stub object support was not the driving force behind that effort, but I certainly had them in mind as I moved forward. The new mapfile syntax, which we call version 2, integrated into Nevada build snv_135 in in February 2010: 6916788 ld version 2 mapfile syntax PSARC/2009/688 Human readable and extensible ld mapfile syntax In order to prove that the new mapfile syntax was adequate for general purpose use, I had also done an overhaul of the ON consolidation to convert all mapfiles to use the new syntax, and put checks in place that would ensure that no use of the old syntax would creep back in. That work went back into snv_144 in June 2010: 6916796 OSnet mapfiles should use version 2 link-editor syntax That was a big putback, modifying 517 files, adding 18 new files, and removing 110 old ones. I would have done this putback anyway, as the work was already done, and the benefits of human readable syntax are obvious. However, among the justifications listed in CR 6916796 was this We anticipate adding additional features to the new mapfile language that will be applicable to ON, and which will require all sharable object mapfiles to use the new syntax. I never explained what those additional features were, and no one asked. It was premature to say so, but this was a reference to stub objects. By that point, I had already put together a working prototype link-editor with the necessary support for stub objects. I was pleased to find that building stubs was indeed very fast. On my desktop system (Ultra 24), an amd64 stub for libc can can be built in a fraction of a second: % ptime ld -64 -z stub -o stubs/libc.so.1 -G -hlibc.so.1 \ -ztext -zdefs -Bdirect ... real 0.019708910 user 0.010101680 sys 0.008528431 In order to go from prototype to integrated link-editor feature, I knew that I would need to prove that stub objects were valuable. And to do that, I knew that I'd have to switch the Solaris ON consolidation to use stub objects and evaluate the outcome. And in order to do that experiment, ON would first need to be converted to version 2 mapfiles. Sub-mission accomplished. Normally when you design a new feature, you can devise reasonably small tests to show it works, and then deploy it incrementally, letting it prove its value as it goes. The entire point of stub objects however was to demonstrate that they could be successfully applied to an extremely large and complex code base, and specifically to solve the Solaris build issues detailed above. There was no way to finesse the matter — in order to move ahead, I would have to successfully use stub objects to build the entire ON consolidation and demonstrate their value. In software, the need to boil the ocean can often be a warning sign that things are trending in the wrong direction. Conversely, sometimes progress demands that you build something large and new all at once. A big win, or a big loss — sometimes all you can do is try it and see what happens. And so, I spent some time staring at ON makefiles trying to get a handle on how things work, and how they'd have to change. It's a big and messy world, full of complex interactions, unspecified dependencies, special cases, and knowledge of arcane makefile features... ...and so, I backed away, put it down for a few months and did other work... ...until the fall, when I felt like it was time to stop thinking and pondering (some would say stalling) and get on with it. Without stubs, the following gives a simplified high level view of how Solaris is built: An initially empty directory known as the proto, and referenced via the ROOT makefile macro is established to receive the files that make up the Solaris distribution. A top level setup rule creates the proto area, and performs operations needed to initialize the workspace so that the main build operations can be launched, such as copying needed header files into the proto area. Parallel builds are launched to build the kernel (usr/src/uts), libraries (usr/src/lib), and commands. The install makefile target builds each item and delivers a copy to the proto area. All libraries and executables link against the objects previously installed in the proto, implying the need to synchronize the order in which things are built. Subsequent passes run lint, and do packaging. Given this structure, the additions to use stub objects are: A new second proto area is established, known as the stub proto and referenced via the STUBROOT makefile macro. The stub proto has the same structure as the real proto, but is used to hold stub objects. All files in the real proto are delivered as part of the Solaris product. In contrast, the stub proto is used to build the product, and then thrown away. A new target is added to library Makefiles called stub. This rule builds the stub objects. The ld command is designed so that you can build a stub object using the same ld command line you'd use to build the real object, with the addition of a single -z stub option. This means that the makefile rules for building the stub objects are very similar to those used to build the real objects, and many existing makefile definitions can be shared between them. A new target is added to the Makefiles called stubinstall which delivers the stub objects built by the stub rule into the stub proto. These rules reuse much of existing plumbing used by the existing install rule. The setup rule runs stubinstall over the entire lib subtree as part of its initialization. All libraries and executables link against the objects in the stub proto rather than the main proto, and can therefore be built in parallel without any synchronization. There was no small way to try this that would yield meaningful results. I would have to take a leap of faith and edit approximately 1850 makefiles and 300 mapfiles first, trusting that it would all work out. Once the editing was done, I'd type make and see what happened. This took about 6 weeks to do, and there were many dark days when I'd question the entire project, or struggle to understand some of the many twisted and complex situations I'd uncover in the makefiles. I even found a couple of new issues that required changes to the new stub object related code I'd added to ld. With a substantial amount of encouragement and help from some key people in the Solaris group, I eventually got the editing done and stub objects for the entire workspace built. I found that my desktop system could build all the stub objects in the workspace in roughly a minute. This was great news, as it meant that use of the feature is effectively free — no one was likely to notice or care about the cost of building them. After another week of typing make, fixing whatever failed, and doing it again, I succeeded in getting a complete build! The next step was to remove all of the make rules and .WAIT statements dedicated to controlling the order in which libraries under usr/src/lib are built. This came together pretty quickly, and after a few more speed bumps, I had a workspace that built cleanly and looked like something you might actually be able to integrate someday. This was a significant milestone, but there was still much left to do. I turned to doing full nightly builds. Every type of build (open, closed, OpenSolaris, export, domestic) had to be tried. Each type failed in a new and unique way, requiring some thinking and rework. As things came together, I became aware of things that could have been done better, simpler, or cleaner, and those things also required some rethinking, the seeking of wisdom from others, and some rework. After another couple of weeks, it was in close to final form. My focus turned towards the end game and integration. This was a huge workspace, and needed to go back soon, before changes in the gate would made merging increasingly difficult. At this point, I knew that the stub objects had greatly simplified the makefile logic and uncovered a number of race conditions, some of which had been there for years. I assumed that the builds were faster too, so I did some builds intended to quantify the speedup in build time that resulted from this approach. It had never occurred to me that there might not be one. And so, I was very surprised to find that the wall clock build times for a stock ON workspace were essentially identical to the times for my stub library enabled version! This is why it is important to always measure, and not just to assume. One can tell from first principles, based on all those removed dependency rules in the library makefile, that the stub object version of ON gives dmake considerably more opportunities to overlap library construction. Some hypothesis were proposed, and shot down: Could we have disabled dmakes parallel feature? No, a quick check showed things being build in parallel. It was suggested that we might be I/O bound, and so, the threads would be mostly idle. That's a plausible explanation, but system stats didn't really support it. Plus, the timing between the stub and non-stub cases were just too suspiciously identical. Are our machines already handling as much parallelism as they are capable of, and unable to exploit these additional opportunities? Once again, we didn't see the evidence to back this up. Eventually, a more plausible and obvious reason emerged: We build the libraries and commands (usr/src/lib, usr/src/cmd) in parallel with the kernel (usr/src/uts). The kernel is the long leg in that race, and so, wall clock measurements of build time are essentially showing how long it takes to build uts. Although it would have been nice to post a huge speedup immediately, we can take solace in knowing that stub objects simplify the makefiles and reduce the possibility of race conditions. The next step in reducing build time should be to find ways to reduce or overlap the uts part of the builds. When that leg of the build becomes shorter, then the increased parallelism in the libs and commands will pay additional dividends. Until then, we'll just have to settle for simpler and more robust. And so, I integrated the link-editor support for creating stub objects into snv_153 (November 2010) with 6993877 ld should produce stub objects PSARC/2010/397 ELF Stub Objects followed by the work to convert the ON consolidation in snv_161 (February 2011) with 7009826 OSnet should use stub objects 4631488 lib/Makefile is too patient: .WAITs should be reduced This was a huge putback, with 2108 modified files, 8 new files, and 2 removed files. Due to the size, I was allowed a window after snv_160 closed in which to do the putback. It went pretty smoothly for something this big, a few more preexisting race conditions would be discovered and addressed over the next few weeks, and things have been quiet since then. Conclusions and Looking Forward Solaris has been built with stub objects since February. The fact that developers no longer specify the order in which libraries are built has been a big success, and we've eliminated an entire class of build error. That's not to say that there are no build races left in the ON makefiles, but we've taken a substantial bite out of the problem while generally simplifying and improving things. The introduction of a stub proto area has also opened some interesting new possibilities for other build improvements. As this article has become quite long, and as those uses do not involve stub objects, I will defer that discussion to a future article.

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• Best practice to query data from MS SQL Server in C Sharp?

  - by Bruno

  What is the best way to query data from a MS SQL Server in C Sharp? I know that it is not good practice to have an SQL query in the code. Is the best way to create a stored procedure and call it from C Sharp with parameters? using (var conn = new SqlConnection(connStr)) using (var command = new SqlCommand("StoredProc", conn) { CommandType = CommandType.StoredProcedure }) { conn.Open(); command.ExecuteNonQuery(); conn.Close(); }

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