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Watching Green Day and discovering Sitecore, priceless.

- by jonel

I’m feeling inspired and I’d like to share a technique we’ve implemented in Sitecore to address a URL mapping from our legacy site that we wanted to carry over to the new beautiful Littelfuse.com. The challenge is to carry over all of our series URLs that have been published in our datasheets, we currently have a lot of series and having to create a manual mapping for those could be really tedious. It has the format of http://www.littelfuse.com/series/series-name.html, for instance, http://www.littelfuse.com/series/flnr.html. It would have been easier if we have our information architecture defined like this but that would have been too easy. I took a solution that is 2-fold. First, I need to create a URL rewrite rule using the IIS URL Rewrite Module 2.0. Secondly, we need to implement a handler that will take care of the actual lookup of the actual series. It will be amazing after we’ve gone over the details. Let’s start with the URL rewrite. Create a new blank rule, you can name it with anything you wish. The key part here to talk about is the Pattern and the Action groups. The Pattern is nothing but regex. Basically, I’m telling it to match the regex I have defined. In the Action group, I am telling it what to do, in this case, rewrite to the redirect.aspx webform. In this implementation, I will be using Rewrite instead of redirect so the URL sticks in the browser. If you opt to use Redirect, then the URL bar will display the new URL our webform will redirect to. Let me explain one small thing, the (\w+) in my Pattern group’s regex, will actually translate to {R:1} in my Action’s group. This is where the magic begins. Now let’s see what our Redirect.aspx contains. Remember our {R:1} above which becomes the query string variable s? This are basic .Net code. The only thing that you will probably ask is the LFSearch class. It’s our own implementation of addressing finding items by using a field search, we supply the fieldname, the value of the field, the template name of the item we are after, and the value of true or false if we want to do an exact search, or not. If eureka, then redirect to that item’s Path (Url). If not, tell the user tough luck, here’s the 404 page as a consolation. Amazing, ain’t it?

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Include weather information in ASP.Net site from weather.com services

- by sreejukg

In this article, I am going to demonstrate how you can use the XMLOAP services (referred as XOAP from here onwards) provided by weather.com to display the weather information in your website. The XOAP services are available to be used for free of charge, provided you are comply with requirements from weather.com. I am writing this article from a technical point of view. If you are planning to use weather.com XOAP services in your application, please refer to the terms and conditions from weather.com website. In order to start using the XOAP services, you need to sign up the XOAP datafeed. The signing process is simple, you simply browse the url http://www.weather.com/services/xmloap.html. The URL looks similar to the following. Click on the sign up button, you will reach the registration page. Here you need to specify the site name you need to use this feed for. The form looks similar to the following. Once you fill all the mandatory information, click on save and continue button. That’s it. The registration is over. You will receive an email that contains your partner id, license key and SDK. The SDK available in a zipped format, contains the terms of use and documentation about the services available. Other than this the SDK includes the logos and icons required to display the weather information. As per the SDK, currently there are 2 types of information available through XOAP. These services are Current Conditions for over 30,000 U.S. and over 7,900 international Location IDs Updated at least Hourly Five-Day Forecast (today + 4 additional forecast days in consecutive order beginning with tomorrow) for over 30,000 U.S. and over 7,900 international Location IDs Updated at least Three Times Daily The SDK provides detailed information about the fields included in response of each service. Additionally there is a refresh rate that you need to comply with. As per the SDK, the refresh rate means the following “Refresh Rate” shall mean the maximum frequency with which you may call the XML Feed for a given LocID requesting a data set for that LocID. During the time period in between refresh periods the data must be cached by you either in the memory on your servers or in Your Desktop Application. About the Services Weather.com will provide you with access to the XML Feed over the Internet through the hostname xoap.weather.com. The weather data from the XML feed must be requested for a specific location. So you need a location ID (LOC ID). The XML feed work with 2 types of location IDs. First one is with City Identifiers and second one is using 5 Digit US postal codes. If you do not know your location ID, don’t worry, there is a location id search service available for you to retrieve the location id from city name. Since I am a resident in the Kingdom of Bahrain, I am going to retrieve the weather information for Manama(the capital of Bahrain) . In order to get the location ID for Manama, type the following URL in your address bar. http://xoap.weather.com/search/search?where=manama I got the following XML output. <?xml version="1.0" encoding="UTF-8"?> <!-- This document is intended only for use by authorized licensees of The –> <!-- Weather Channel. Unauthorized use is prohibited. Copyright 1995-2011, –> <!-- The Weather Channel Interactive, Inc. All Rights Reserved. –> <search ver="3.0"> <loc id="BAXX0001" type="1">Al Manama, Bahrain</loc> </search> You can try this with any city name, if the city is available, it will return the location id, and otherwise, it will return nothing. In order to get the weather information, from XOAP, you need to pass certain parameters to the XOAP service. A brief about the parameters are as follows. Please refer SDK for more details. Parameter name Possible Value cc Optional, if you include this, the current condition will be returned. Value can be anything, as it will be ignored e.g. cc=* dayf If you want the forecast for 5 days, specify dayf=5 This is optional iink Value should be XOAP par Your partner id. You can find this in your registration email from weather.com prod Value should be XOAP key The license key assigned to you. This will be available in the registration email unit s or m (standard or matric or you can think of Celsius/Fahrenheit) this is optional field, if not specified the unit will be standard(s) The URL host for the XOAP service is http://xoap.weather.com. So for my purpose, I need the following request to be made to access the XOAP services. http://xoap.weather.com/weather/local/BAXX0001?cc=*&link=xoap&prod=xoap&par=*********&key=************** (The ***** to be replaced with the corresponding alternatives) The response XML have a root element “weather”. Under the root element, it has the following sections <head> - the meta data information about the weather results returned. <loc> - the location data block that provides, the information about the location for which the wheather data is retrieved. <lnks> - the 4 promotional links you need to place along with the weather display. Additional to these 4 links, there should be another link with weather channel logo to the home page of weather.com. <cc> - the current condition data. This element will be there only if you specify the cc element in the request. <dayf> - the forcast data as you specified. This element will be there only if you specify the dayf in the request. In this walkthrough, I am going to capture the weather information for Manama (Location ID: BAXX0001). You need 2 applications to display weather information in your website. A Console application that retrieves data from the XMLOAP and store in the SQL Server database (or any data store as you prefer).This application will be scheduled to execute in every 25 minutes using windows task scheduler, so that we can comply with the refresh rate. A web application that display data from the SQL Server database Retrieve the Weather from XOAP I have created a console application named, Weather Service. I created a SQL server database, with the following columns. I named the table as tblweather. You are free to choose any name. Column name Description lastUpdated Datetime, this is the last time when the weather data is updated. This is the time of the service running TemparatureDateTime The date and time returned by XML feed Temparature The temperature returned by the XML feed. TemparatureUnit The unit of the temperature returned by the XML feed iconId The id of the icon to be used. Currently 48 icons from 0 to 47 are available. WeatherDescription The Weather Description Phrase returned by the feed. Link1url The url to the first promo link Link1Text The text for the first promo link Link2url The url to the second promo link Link2Text The text for the second promo link Link3url The url to the third promo link Link3Text The text for the third promo link Link4url The url to the fourth promo link Link4Text The text for the fourth promo link Every time when the service runs, the application will update the database columns from the XOAP data feed. When the application starts, It is going to get the data as XML from the url. This demonstration uses LINQ to extract the necessary data from the fetched XML. The following are the code segment for extracting data from the weather XML using LINQ. // first, create an instance of the XDocument class with the XOAP URL. replace **** with the corresponding values. XDocument weather = XDocument.Load("http://xoap.weather.com/weather/local/BAXX0001?cc=*&link=xoap&prod=xoap&par=***********&key=c*********"); // construct a query using LINQ var feedResult = from item in weather.Descendants() select new { unit = item.Element("head").Element("ut").Value, temp = item.Element("cc").Element("tmp").Value, tempDate = item.Element("cc").Element("lsup").Value, iconId = item.Element("cc").Element("icon").Value, description = item.Element("cc").Element("t").Value, links = from link in item.Elements("lnks").Elements("link") select new { url = link.Element("l").Value, text = link.Element("t").Value } }; // Load the root node to a variable, you may use foreach construct instead. var item1 = feedResult.First(); *If you want to learn more about LINQ and XML, read this nice blog from Scott GU. http://weblogs.asp.net/scottgu/archive/2007/08/07/using-linq-to-xml-and-how-to-build-a-custom-rss-feed-reader-with-it.aspx Now you have all the required values in item1. For e.g. if you want to get the temperature, use item1.temp; Now I just need to execute an SQL query against the database. See the connection part. using (SqlConnection conn = new SqlConnection(@"Data Source=sreeju\sqlexpress;Initial Catalog=Sample;Integrated Security=True")) { string strSql = @"update tblweather set lastupdated=getdate(), temparatureDateTime = @temparatureDateTime, temparature=@temparature, temparatureUnit=@temparatureUnit, iconId = @iconId, description=@description, link1url=@link1url, link1text=@link1text, link2url=@link2url, link2text=@link2text,link3url=@link3url, link3text=@link3text,link4url=@link4url, link4text=@link4text"; SqlCommand comm = new SqlCommand(strSql, conn); comm.Parameters.AddWithValue("temparatureDateTime", item1.tempDate); comm.Parameters.AddWithValue("temparature", item1.temp); comm.Parameters.AddWithValue("temparatureUnit", item1.unit); comm.Parameters.AddWithValue("description", item1.description); comm.Parameters.AddWithValue("iconId", item1.iconId); var lstLinks = item1.links; comm.Parameters.AddWithValue("link1url", lstLinks.ElementAt(0).url); comm.Parameters.AddWithValue("link1text", lstLinks.ElementAt(0).text); comm.Parameters.AddWithValue("link2url", lstLinks.ElementAt(1).url); comm.Parameters.AddWithValue("link2text", lstLinks.ElementAt(1).text); comm.Parameters.AddWithValue("link3url", lstLinks.ElementAt(2).url); comm.Parameters.AddWithValue("link3text", lstLinks.ElementAt(2).text); comm.Parameters.AddWithValue("link4url", lstLinks.ElementAt(3).url); comm.Parameters.AddWithValue("link4text", lstLinks.ElementAt(3).text); conn.Open(); comm.ExecuteNonQuery(); conn.Close(); Console.WriteLine("database updated"); } Now click ctrl + f5 to run the service. I got the following output Check your database and make sure, the data is updated with the latest information from the service. (Make sure you inserted one row in the database by entering some values before executing the service. Otherwise you need to modify your application code to count the rows and conditionally perform insert/update query) Display the Weather information in ASP.Net page Now you got all the data in the database. You just need to create a web application and display the data from the database. I created a new ASP.Net web application with a default.aspx page. In order to comply with the terms of weather.com, You need to use Weather.com logo along with the weather display. You can find the necessary logos to use under the folder “logos” in the SDK. Additionally copy any of the icon set from the folder “icons” to your web application. I used the 93x93 icon set. You are free to use any other sizes available. The design view of the page in VS2010 looks similar to the following. The page contains a heading, an image control (for displaying the weather icon), 2 label controls (for displaying temperature and weather description), 4 hyperlinks (for displaying the 4 promo links returned by the XOAP service) and weather.com logo with hyperlink to the weather.com home page. I am going to write code that will update the values of these controls from the values stored in the database by the service application as mentioned in the previous step. Go to the code behind file for the webpage, enter the following code under Page_Load event handler. using (SqlConnection conn = new SqlConnection(@"Data Source=sreeju\sqlexpress;Initial Catalog=Sample;Integrated Security=True")) { SqlCommand comm = new SqlCommand("select top 1 * from tblweather", conn); conn.Open(); SqlDataReader reader = comm.ExecuteReader(); if (reader.Read()) { lblTemparature.Text = reader["temparature"].ToString() + "°" + reader["temparatureUnit"].ToString(); lblWeatherDescription.Text = reader["description"].ToString(); imgWeather.ImageUrl = "icons/" + reader["iconId"].ToString() + ".png"; lnk1.Text = reader["link1text"].ToString(); lnk1.NavigateUrl = reader["link1url"].ToString(); lnk2.Text = reader["link2text"].ToString(); lnk2.NavigateUrl = reader["link2url"].ToString(); lnk3.Text = reader["link3text"].ToString(); lnk3.NavigateUrl = reader["link3url"].ToString(); lnk4.Text = reader["link4text"].ToString(); lnk4.NavigateUrl = reader["link4url"].ToString(); } conn.Close(); } Press ctrl + f5 to run the page. You will see the following output. That’s it. You need to configure the console application to run every 25 minutes so that the database is updated. Also you can fetch the forecast information and store those in the database, and then retrieve it later in your web page. Since the data resides in your database, you have the full control over your display. You need to make sure your website comply with weather.com license requirements. If you want to get the source code of this walkthrough through the application, post your email address below. Hope you enjoy the reading.

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NoSQL with MongoDB, NoRM and ASP.NET MVC - Part 2

- by shiju

In my last post, I have given an introduction to MongoDB and NoRM using an ASP.NET MVC demo app. I have updated the demo ASP.NET MVC app and a created a new drop at codeplex. You can download the demo at http://mongomvc.codeplex.com/In my last post, we have discussed to doing basic CRUD operations against a simple domain entity. In this post, let’s discuss on domain entity with deep object graph.The below is our domain entities public class Category { [MongoIdentifier] public ObjectId Id { get; set; } [Required(ErrorMessage = "Name Required")] [StringLength(25, ErrorMessage = "Must be less than 25 characters")] public string Name { get; set;} public string Description { get; set; } public List<Expense> Expenses { get; set; } public Category() { Expenses = new List<Expense>(); } } public class Expense { [MongoIdentifier] public ObjectId Id { get; set; } public Category Category { get; set; } public string Transaction { get; set; } public DateTime Date { get; set; } public double Amount { get; set; } } We have two domain entities - Category and Expense. A single category contains a list of expense transactions and every expense transaction should have a Category.The MongoSession class internal class MongoSession : IDisposable { private readonly MongoQueryProvider provider; public MongoSession() { this.provider = new MongoQueryProvider("Expense"); } public IQueryable<Category> Categories { get { return new MongoQuery<Category>(this.provider); } } public IQueryable<Expense> Expenses { get { return new MongoQuery<Expense>(this.provider); } } public MongoQueryProvider Provider { get { return this.provider; } } public void Add<T>(T item) where T : class, new() { this.provider.DB.GetCollection<T>().Insert(item); } public void Dispose() { this.provider.Server.Dispose(); } public void Delete<T>(T item) where T : class, new() { this.provider.DB.GetCollection<T>().Delete(item); } public void Drop<T>() { this.provider.DB.DropCollection(typeof(T).Name); } public void Save<T>(T item) where T : class,new() { this.provider.DB.GetCollection<T>().Save(item); } } ASP.NET MVC view model for Expense transaction public class ExpenseViewModel { public ObjectId Id { get; set; } public ObjectId CategoryId { get; set; } [Required(ErrorMessage = "Transaction Required")] public string Transaction { get; set; } [Required(ErrorMessage = "Date Required")] public DateTime Date { get; set; } [Required(ErrorMessage = "Amount Required")] public double Amount { get; set; } public IEnumerable<SelectListItem> Category { get; set; } } Let's create action method for Insert and Update a expense transaction [HttpPost] public ActionResult Save(ExpenseViewModel expenseViewModel) { try { if (!ModelState.IsValid) { using (var session = new MongoSession()) { var categories = session.Categories.AsEnumerable<Category>(); expenseViewModel.Category = categories.ToSelectListItems(expenseViewModel.CategoryId); } return View("Save", expenseViewModel); } var expense=new Expense(); ModelCopier.CopyModel(expenseViewModel, expense); using (var session = new MongoSession()) { ObjectId Id = expenseViewModel.CategoryId; var category = session.Categories .Where(c => c.Id ==Id ) .FirstOrDefault(); expense.Category = category; session.Save(expense); } return RedirectToAction("Index"); } catch { return View(); } } Query with Expenses using (var session = new MongoSession()) { var expenses = session.Expenses. Where(exp => exp.Date >= StartDate && exp.Date <= EndDate) .AsEnumerable<Expense>(); } We are doing a LINQ query expression with a Date filter. We can easily work with MongoDB using NoRM driver and can managing object graph of domain entities are pretty cool. Download the Source - You can download the source code form http://mongomvc.codeplex.com

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Asynchronous Streaming in ASP.NET WebApi

- by andresv

Hi everyone, if you use the cool MVC4 WebApi you might encounter yourself in a common situation where you need to return a rather large amount of data (most probably from a database) and you want to accomplish two things: Use streaming so the client fetch the data as needed, and that directly correlates to more fetching in the server side (from our database, for example) without consuming large amounts of memory. Leverage the new MVC4 WebApi and .NET 4.5 async/await asynchronous execution model to free ASP.NET Threadpool threads (if possible). So, #1 and #2 are not directly related to each other and we could implement our code fulfilling one or the other, or both. The main point about #1 is that we want our method to immediately return to the caller a stream, and that client side stream be represented by a server side stream that gets written (and its related database fetch) only when needed. In this case we would need some form of "state machine" that keeps running in the server and "knows" what is the next thing to fetch into the output stream when the client ask for more content. This technique is generally called a "continuation" and is nothing new in .NET, in fact using an IEnumerable<> interface and the "yield return" keyword does exactly that, so our first impulse might be to write our WebApi method more or less like this: public IEnumerable<Metadata> Get([FromUri] int accountId) { // Execute the command and get a reader using (var reader = GetMetadataListReader(accountId)) { // Read rows asynchronously, put data into buffer and write asynchronously while (reader.Read()) { yield return MapRecord(reader); } } } While the above method works, unfortunately it doesn't accomplish our objective of returning immediately to the caller, and that's because the MVC WebApi infrastructure doesn't yet recognize our intentions and when it finds an IEnumerable return value, enumerates it before returning to the client its values. To prove my point, I can code a test method that calls this method, for example: [TestMethod] public void StreamedDownload() { var baseUrl = @"http://localhost:57771/api/metadata/1"; var client = new HttpClient(); var sw = Stopwatch.StartNew(); var stream = client.GetStreamAsync(baseUrl).Result; sw.Stop(); Debug.WriteLine("Elapsed time Call: {0}ms", sw.ElapsedMilliseconds); } So, I would expect the line "var stream = client.GetStreamAsync(baseUrl).Result" returns immediately without server-side fetching of all data in the database reader, and this didn't happened. To make the behavior more evident, you could insert a wait time (like Thread.Sleep(1000);) inside the "while" loop, and you will see that the client call (GetStreamAsync) is not going to return control after n seconds (being n == number of reader records being fetched).Ok, we know this doesn't work, and the question would be: is there a way to do it?Fortunately, YES! and is not very difficult although a little more convoluted than our simple IEnumerable return value. Maybe in the future this scenario will be automatically detected and supported in MVC/WebApi.The solution to our needs is to use a very handy class named PushStreamContent and then our method signature needs to change to accommodate this, returning an HttpResponseMessage instead of our previously used IEnumerable<>. The final code will be something like this: public HttpResponseMessage Get([FromUri] int accountId) { HttpResponseMessage response = Request.CreateResponse(); // Create push content with a delegate that will get called when it is time to write out // the response. response.Content = new PushStreamContent( async (outputStream, httpContent, transportContext) => { try { // Execute the command and get a reader using (var reader = GetMetadataListReader(accountId)) { // Read rows asynchronously, put data into buffer and write asynchronously while (await reader.ReadAsync()) { var rec = MapRecord(reader); var str = await JsonConvert.SerializeObjectAsync(rec); var buffer = UTF8Encoding.UTF8.GetBytes(str); // Write out data to output stream await outputStream.WriteAsync(buffer, 0, buffer.Length); } } } catch(HttpException ex) { if (ex.ErrorCode == -2147023667) // The remote host closed the connection. { return; } } finally { // Close output stream as we are done outputStream.Close(); } }); return response; } As an extra bonus, all involved classes used already support async/await asynchronous execution model, so taking advantage of that was very easy. Please note that the PushStreamContent class receives in its constructor a lambda (specifically an Action) and we decorated our anonymous method with the async keyword (not a very well known technique but quite handy) so we can await over the I/O intensive calls we execute like reading from the database reader, serializing our entity and finally writing to the output stream. Well, if we execute the test again we will immediately notice that the a line returns immediately and then the rest of the server code is executed only when the client reads through the obtained stream, therefore we get low memory usage and far greater scalability for our beloved application serving big chunks of data.Enjoy!Andrés.

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the size of apt-get update lists is too big

- by dumb906

I ran a clean install to Ubuntu 12.04 and so far everything has been working well. I especially commend the Ubuntu team for this release. I only noticed that the size of repository update is now about ~13MB. Normally, it is about this size for the first time you run apt-get update after a clean install and then ~ 23kb - 1300kb for subsequent updates. The output from apt-get update is the same I get for previous versions of Ubuntu (its pretty normal). Its a bit too long but look at an example output I got from running apt-get update. Ign http://archive.canonical.com precise InRelease Ign http://dl.google.com stable InRelease Ign http://dl.google.com stable InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Hit http://download.virtualbox.org precise InRelease Ign http://security.ubuntu.com precise-security InRelease Ign http://linux.dropbox.com precise InRelease Ign http://extras.ubuntu.com precise InRelease Ign http://download.skype.com stable InRelease Hit http://archive.canonical.com precise Release.gpg Get:1 http://dl.google.com stable Release.gpg [198 B] Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net oneiric InRelease Ign http://ppa.launchpad.net precise InRelease Get:2 http://security.ubuntu.com precise-security Release.gpg [198 B] Get:3 http://extras.ubuntu.com precise Release.gpg [72 B] Hit http://download.virtualbox.org precise/contrib i386 Packages Ign http://download.skype.com stable Release.gpg Hit http://linux.dropbox.com precise Release.gpg Ign http://us.archive.ubuntu.com precise InRelease Ign http://us.archive.ubuntu.com precise-updates InRelease Ign http://us.archive.ubuntu.com precise-backports InRelease Hit http://archive.canonical.com precise Release Get:4 http://dl.google.com stable Release.gpg [198 B] Ign http://ppa.launchpad.net oneiric InRelease Ign http://ppa.launchpad.net oneiric InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Hit http://ppa.launchpad.net precise Release.gpg Hit http://ppa.launchpad.net precise Release.gpg Get:5 http://security.ubuntu.com precise-security Release [49.6 kB] Hit http://extras.ubuntu.com precise Release Ign http://download.skype.com stable Release Ign http://download.virtualbox.org precise/contrib TranslationIndex Get:6 http://us.archive.ubuntu.com precise Release.gpg [198 B] Hit http://archive.canonical.com precise/partner i386 Packages Hit http://linux.dropbox.com precise Release Get:7 http://ppa.launchpad.net precise Release.gpg [316 B] Hit http://ppa.launchpad.net precise Release.gpg Hit http://ppa.launchpad.net precise Release.gpg Hit http://extras.ubuntu.com precise/main Sources Get:8 http://ppa.launchpad.net precise Release.gpg [316 B] Hit http://ppa.launchpad.net precise Release.gpg Hit http://ppa.launchpad.net precise Release.gpg Hit http://ppa.launchpad.net precise Release.gpg Hit http://ppa.launchpad.net precise Release.gpg Get:9 http://us.archive.ubuntu.com precise-updates Release.gpg [198 B] Ign http://archive.canonical.com precise/partner TranslationIndex Ign http://download.skype.com stable/non-free i386 Packages/DiffIndex Get:10 http://dl.google.com stable Release [1,347 B] Hit http://linux.dropbox.com precise/main i386 Packages Hit http://ppa.launchpad.net precise Release.gpg Hit http://ppa.launchpad.net oneiric Release.gpg Hit http://extras.ubuntu.com precise/main i386 Packages Ign http://extras.ubuntu.com precise/main TranslationIndex Hit http://ppa.launchpad.net precise Release.gpg Hit http://ppa.launchpad.net oneiric Release.gpg Hit http://ppa.launchpad.net oneiric Release.gpg Hit http://ppa.launchpad.net precise Release.gpg Hit http://ppa.launchpad.net precise Release.gpg Get:11 http://us.archive.ubuntu.com precise-backports Release.gpg [198 B] Ign http://download.skype.com stable/non-free TranslationIndex Get:12 http://dl.google.com stable Release [1,347 B] Hit http://ppa.launchpad.net precise Release.gpg Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net precise Release Ign http://linux.dropbox.com precise/main TranslationIndex Hit http://ppa.launchpad.net precise Release Ign http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net precise Release Get:13 http://ppa.launchpad.net precise Release [11.9 kB] Get:14 http://us.archive.ubuntu.com precise Release [49.6 kB] Hit http://download.skype.com stable/non-free i386 Packages Get:15 http://dl.google.com stable/main i386 Packages [1,268 B] Ign http://dl.google.com stable/main TranslationIndex Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net oneiric Release Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net oneiric Release Get:16 http://security.ubuntu.com precise-security/main Sources [7,089 B] Hit http://ppa.launchpad.net oneiric Release Get:17 http://dl.google.com stable/main i386 Packages [769 B] Ign http://dl.google.com stable/main TranslationIndex Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net precise Release Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main i386 Packages Get:18 http://security.ubuntu.com precise-security/restricted Sources [14 B] Get:19 http://security.ubuntu.com precise-security/universe Sources [3,653 B] Get:20 http://security.ubuntu.com precise-security/multiverse Sources [696 B] Get:21 http://security.ubuntu.com precise-security/main i386 Packages [32.9 kB] Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Get:22 http://us.archive.ubuntu.com precise-updates Release [49.6 kB] Ign http://ppa.launchpad.net precise/main Sources/DiffIndex Ign http://ppa.launchpad.net precise/main i386 Packages/DiffIndex Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main i386 Packages Get:23 http://security.ubuntu.com precise-security/restricted i386 Packages [14 B] Get:24 http://security.ubuntu.com precise-security/universe i386 Packages [8,594 B] Get:25 http://security.ubuntu.com precise-security/multiverse i386 Packages [1,393 B] Hit http://security.ubuntu.com precise-security/main TranslationIndex Hit http://security.ubuntu.com precise-security/multiverse TranslationIndex Hit http://security.ubuntu.com precise-security/restricted TranslationIndex Hit http://security.ubuntu.com precise-security/universe TranslationIndex Ign http://ppa.launchpad.net precise/main TranslationIndex Get:26 http://us.archive.ubuntu.com precise-backports Release [49.6 kB] Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Get:27 http://ppa.launchpad.net precise/main i386 Packages [1,276 B] Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Get:28 http://us.archive.ubuntu.com precise/main Sources [934 kB] Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main i386 Packages Hit http://security.ubuntu.com precise-security/main Translation-en Hit http://security.ubuntu.com precise-security/multiverse Translation-en Hit http://security.ubuntu.com precise-security/restricted Translation-en Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net oneiric/main Sources Hit http://ppa.launchpad.net oneiric/main i386 Packages Ign http://ppa.launchpad.net oneiric/main TranslationIndex Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net oneiric/main Sources Hit http://security.ubuntu.com precise-security/universe Translation-en Ign http://archive.canonical.com precise/partner Translation-en_US Hit http://ppa.launchpad.net oneiric/main i386 Packages Ign http://ppa.launchpad.net oneiric/main TranslationIndex Hit http://ppa.launchpad.net oneiric/main Sources Hit http://ppa.launchpad.net oneiric/main i386 Packages Ign http://ppa.launchpad.net oneiric/main TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Ign http://extras.ubuntu.com precise/main Translation-en_US Ign http://download.virtualbox.org precise/contrib Translation-en_US Ign http://archive.canonical.com precise/partner Translation-en Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Ign http://extras.ubuntu.com precise/main Translation-en Ign http://download.virtualbox.org precise/contrib Translation-en Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Ign http://linux.dropbox.com precise/main Translation-en_US Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://download.skype.com stable/non-free Translation-en_US Ign http://linux.dropbox.com precise/main Translation-en Ign http://download.skype.com stable/non-free Translation-en Ign http://dl.google.com stable/main Translation-en_US Ign http://dl.google.com stable/main Translation-en Ign http://dl.google.com stable/main Translation-en_US Get:29 http://us.archive.ubuntu.com precise/restricted Sources [5,470 B] Get:30 http://us.archive.ubuntu.com precise/universe Sources [5,019 kB] Ign http://dl.google.com stable/main Translation-en Get:31 http://us.archive.ubuntu.com precise/multiverse Sources [155 kB] Get:32 http://us.archive.ubuntu.com precise/main i386 Packages [1,274 kB] Get:33 http://us.archive.ubuntu.com precise/restricted i386 Packages [8,431 B] Get:34 http://us.archive.ubuntu.com precise/universe i386 Packages [4,796 kB] Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net oneiric/main Translation-en_US Ign http://ppa.launchpad.net oneiric/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net oneiric/main Translation-en_US Ign http://ppa.launchpad.net oneiric/main Translation-en Ign http://ppa.launchpad.net oneiric/main Translation-en_US Ign http://ppa.launchpad.net oneiric/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Get:35 http://us.archive.ubuntu.com precise/multiverse i386 Packages [121 kB] Hit http://us.archive.ubuntu.com precise/main TranslationIndex Hit http://us.archive.ubuntu.com precise/multiverse TranslationIndex Hit http://us.archive.ubuntu.com precise/restricted TranslationIndex Hit http://us.archive.ubuntu.com precise/universe TranslationIndex Get:36 http://us.archive.ubuntu.com precise-updates/main Sources [31.2 kB] Get:37 http://us.archive.ubuntu.com precise-updates/restricted Sources [765 B] Get:38 http://us.archive.ubuntu.com precise-updates/universe Sources [10.1 kB] Get:39 http://us.archive.ubuntu.com precise-updates/multiverse Sources [696 B] Get:40 http://us.archive.ubuntu.com precise-updates/main i386 Packages [96.5 kB] Get:41 http://us.archive.ubuntu.com precise-updates/restricted i386 Packages [770 B] Get:42 http://us.archive.ubuntu.com precise-updates/universe i386 Packages [27.7 kB] Get:43 http://us.archive.ubuntu.com precise-updates/multiverse i386 Packages [1,393 B] Hit http://us.archive.ubuntu.com precise-updates/main TranslationIndex Hit http://us.archive.ubuntu.com precise-updates/multiverse TranslationIndex Hit http://us.archive.ubuntu.com precise-updates/restricted TranslationIndex Hit http://us.archive.ubuntu.com precise-updates/universe TranslationIndex Get:44 http://us.archive.ubuntu.com precise-backports/main Sources [700 B] Get:45 http://us.archive.ubuntu.com precise-backports/restricted Sources [14 B] Get:46 http://us.archive.ubuntu.com precise-backports/universe Sources [1,680 B] Get:47 http://us.archive.ubuntu.com precise-backports/multiverse Sources [14 B] Get:48 http://us.archive.ubuntu.com precise-backports/main i386 Packages [559 B] Get:49 http://us.archive.ubuntu.com precise-backports/restricted i386 Packages [14 B] Get:50 http://us.archive.ubuntu.com precise-backports/universe i386 Packages [1,391 B] Get:51 http://us.archive.ubuntu.com precise-backports/multiverse i386 Packages [14 B] Hit http://us.archive.ubuntu.com precise-backports/main TranslationIndex Hit http://us.archive.ubuntu.com precise-backports/multiverse TranslationIndex Hit http://us.archive.ubuntu.com precise-backports/restricted TranslationIndex Hit http://us.archive.ubuntu.com precise-backports/universe TranslationIndex Hit http://us.archive.ubuntu.com precise/main Translation-en Hit http://us.archive.ubuntu.com precise/multiverse Translation-en Hit http://us.archive.ubuntu.com precise/restricted Translation-en Hit http://us.archive.ubuntu.com precise/universe Translation-en Hit http://us.archive.ubuntu.com precise-updates/main Translation-en Hit http://us.archive.ubuntu.com precise-updates/multiverse Translation-en Hit http://us.archive.ubuntu.com precise-updates/restricted Translation-en Hit http://us.archive.ubuntu.com precise-updates/universe Translation-en Hit http://us.archive.ubuntu.com precise-backports/main Translation-en Hit http://us.archive.ubuntu.com precise-backports/multiverse Translation-en Hit http://us.archive.ubuntu.com precise-backports/restricted Translation-en Hit http://us.archive.ubuntu.com precise-backports/universe Translation-en Fetched 12.8 MB in 1min 33s (137 kB/s) Is this a new feature in 12.04? Or, if it is unintended, is there a way I can fix this? Thanks.

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Guarding against CSRF Attacks in ASP.NET MVC2

- by srkirkland

Alongside XSS (Cross Site Scripting) and SQL Injection, Cross-site Request Forgery (CSRF) attacks represent the three most common and dangerous vulnerabilities to common web applications today. CSRF attacks are probably the least well known but they are relatively easy to exploit and extremely and increasingly dangerous. For more information on CSRF attacks, see these posts by Phil Haack and Steve Sanderson. The recognized solution for preventing CSRF attacks is to put a user-specific token as a hidden field inside your forms, then check that the right value was submitted. It's best to use a random value which you’ve stored in the visitor’s Session collection or into a Cookie (so an attacker can't guess the value). ASP.NET MVC to the rescue ASP.NET MVC provides an HTMLHelper called AntiForgeryToken(). When you call <%= Html.AntiForgeryToken() %> in a form on your page you will get a hidden input and a Cookie with a random string assigned. Next, on your target Action you need to include [ValidateAntiForgeryToken], which handles the verification that the correct token was supplied. Good, but we can do better Using the AntiForgeryToken is actually quite an elegant solution, but adding [ValidateAntiForgeryToken] on all of your POST methods is not very DRY, and worse can be easily forgotten. Let's see if we can make this easier on the program but moving from an "Opt-In" model of protection to an "Opt-Out" model. Using AntiForgeryToken by default In order to mandate the use of the AntiForgeryToken, we're going to create an ActionFilterAttribute which will do the anti-forgery validation on every POST request. First, we need to create a way to Opt-Out of this behavior, so let's create a quick action filter called BypassAntiForgeryToken: [AttributeUsage(AttributeTargets.Method, AllowMultiple=false)] public class BypassAntiForgeryTokenAttribute : ActionFilterAttribute { } Now we are ready to implement the main action filter which will force anti forgery validation on all post actions within any class it is defined on: [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)] public class UseAntiForgeryTokenOnPostByDefault : ActionFilterAttribute { public override void OnActionExecuting(ActionExecutingContext filterContext) { if (ShouldValidateAntiForgeryTokenManually(filterContext)) { var authorizationContext = new AuthorizationContext(filterContext.Controller.ControllerContext); //Use the authorization of the anti forgery token, //which can't be inhereted from because it is sealed new ValidateAntiForgeryTokenAttribute().OnAuthorization(authorizationContext); } base.OnActionExecuting(filterContext); } /// <summary> /// We should validate the anti forgery token manually if the following criteria are met: /// 1. The http method must be POST /// 2. There is not an existing [ValidateAntiForgeryToken] attribute on the action /// 3. There is no [BypassAntiForgeryToken] attribute on the action /// </summary> private static bool ShouldValidateAntiForgeryTokenManually(ActionExecutingContext filterContext) { var httpMethod = filterContext.HttpContext.Request.HttpMethod; //1. The http method must be POST if (httpMethod != "POST") return false; // 2. There is not an existing anti forgery token attribute on the action var antiForgeryAttributes = filterContext.ActionDescriptor.GetCustomAttributes(typeof(ValidateAntiForgeryTokenAttribute), false); if (antiForgeryAttributes.Length > 0) return false; // 3. There is no [BypassAntiForgeryToken] attribute on the action var ignoreAntiForgeryAttributes = filterContext.ActionDescriptor.GetCustomAttributes(typeof(BypassAntiForgeryTokenAttribute), false); if (ignoreAntiForgeryAttributes.Length > 0) return false; return true; } } The code above is pretty straight forward -- first we check to make sure this is a POST request, then we make sure there aren't any overriding *AntiForgeryTokenAttributes on the action being executed. If we have a candidate then we call the ValidateAntiForgeryTokenAttribute class directly and execute OnAuthorization() on the current authorization context. Now on our base controller, you could use this new attribute to start protecting your site from CSRF vulnerabilities. [UseAntiForgeryTokenOnPostByDefault] public class ApplicationController : System.Web.Mvc.Controller { } //Then for all of your controllers public class HomeController : ApplicationController {} What we accomplished If your base controller has the new default anti-forgery token attribute on it, when you don't use <%= Html.AntiForgeryToken() %> in a form (or of course when an attacker doesn't supply one), the POST action will throw the descriptive error message "A required anti-forgery token was not supplied or was invalid". Attack foiled! In summary, I think having an anti-CSRF policy by default is an effective way to protect your websites, and it turns out it is pretty easy to accomplish as well. Enjoy!

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Creating an ASP.NET report using Visual Studio 2010 - Part 3

- by rajbk

We continue building our report in this three part series. Creating an ASP.NET report using Visual Studio 2010 - Part 1 Creating an ASP.NET report using Visual Studio 2010 - Part 2 Adding the ReportViewer control and filter drop downs. Open the source code for index.aspx and add a ScriptManager control. This control is required for the ReportViewer control. Add a DropDownList for the categories and suppliers. Add the ReportViewer control. The markup after these steps is shown below. <div> <asp:ScriptManager ID="smScriptManager" runat="server"> </asp:ScriptManager> <div id="searchFilter"> Filter by: Category : <asp:DropDownList ID="ddlCategories" runat="server" /> and Supplier : <asp:DropDownList ID="ddlSuppliers" runat="server" /> </div> <rsweb:ReportViewer ID="rvProducts" runat="server"> </rsweb:ReportViewer> </div> The design view for index.aspx is shown below. The dropdowns will display the categories and suppliers in the database. Changing the selection in the drop downs will cause the report to be filtered by the selections in the dropdowns. You will see how to do this in the next steps. Attaching the RDLC to the ReportViewer control by clicking on the top right of the control, going to Report Viewer tasks and selecting Products.rdlc. Resize the ReportViewer control by dragging at the bottom right corner. I set mine to 800px x 500px. You can also set this value in source view. Defining the data sources. We will now define the Data Source used to populate the report. Go back to the “ReportViewer Tasks” and select “Choose Data Sources” Select a “New data source..” Select “Object” and name your Data Source ID “odsProducts” In the next screen, choose “ProductRepository” as your business object. Choose “GetProductsProjected” in the next screen. The method requires a SupplierID and CategoryID. We will set these so that our data source gets the values from the drop down lists we defined earlier. Set the parameter source to be of type “Control” and set the ControlIDs to be ddlSuppliers and ddlCategories respectively. Your screen will look like this: We are now going to define the data source for our drop downs. Select the ddlCategory drop down and pick “Choose Data Source”. Pick “Object” and give it an id “odsCategories” In the next screen, choose “ProductRepository” Select the GetCategories() method in the next screen. Select “CategoryName” and “CategoryID” in the next screen. We are done defining the data source for the Category drop down. Perform the same steps for the Suppliers drop down. Select each dropdown and set the AppendDataBoundItems to true and AutoPostback to true. The AppendDataBoundItems is needed because we are going to insert an “All“ list item with a value of empty. Go to each drop down and add this list item markup as shown below> Finally, double click on each drop down in the designer and add the following code in the code behind. This along with the “Autopostback= true” attribute refreshes the report anytime a drop down is changed. protected void ddlCategories_SelectedIndexChanged(object sender, EventArgs e) { rvProducts.LocalReport.Refresh(); } protected void ddlSuppliers_SelectedIndexChanged(object sender, EventArgs e) { rvProducts.LocalReport.Refresh(); } Compile your report and run the page. You should see the report rendered. Note that the tool bar in the ReportViewer control gives you a couple of options including the ability to export the data to Excel, PDF or word. Conclusion Through this three part series, we did the following: Created a data layer for use by our RDLC. Created an RDLC using the report wizard and define a dataset for the report. Used the report design surface to design our report including adding a chart. Used the ReportViewer control to attach the RDLC. Connected our ReportWiewer to a data source and take parameter values from the drop downlists. Used AutoPostBack to refresh the reports when the dropdown selection was changed. RDLCs allow you to create interactive reports including drill downs and grouping. For even more advanced reports you can use Microsoft® SQL Server™ Reporting Services with RDLs. With RDLs, the report is rendered on the report server instead of the web server. Another nice thing about RDLs is that you can define a parameter list for the report and it gets rendered automatically for you. RDLCs and RDLs both have their advantages and its best to compare them and choose the right one for your requirements. Download VS2010 RTM Sample project NorthwindReports.zip Alfred Borden: Are you watching closely?

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ASP.NET MVC 3: Razor’s @: and <text> syntax

- by ScottGu

This is another in a series of posts I’m doing that cover some of the new ASP.NET MVC 3 features: New @model keyword in Razor (Oct 19th) Layouts with Razor (Oct 22nd) Server-Side Comments with Razor (Nov 12th) Razor’s @: and <text> syntax (today) In today’s post I’m going to discuss two useful syntactical features of the new Razor view-engine – the @: and <text> syntax support. Fluid Coding with Razor ASP.NET MVC 3 ships with a new view-engine option called “Razor” (in addition to the existing .aspx view engine). You can learn more about Razor, why we are introducing it, and the syntax it supports from my Introducing Razor blog post. Razor minimizes the number of characters and keystrokes required when writing a view template, and enables a fast, fluid coding workflow. Unlike most template syntaxes, you do not need to interrupt your coding to explicitly denote the start and end of server blocks within your HTML. The Razor parser is smart enough to infer this from your code. This enables a compact and expressive syntax which is clean, fast and fun to type. For example, the Razor snippet below can be used to iterate a list of products: When run, it generates output like: One of the techniques that Razor uses to implicitly identify when a code block ends is to look for tag/element content to denote the beginning of a content region. For example, in the code snippet above Razor automatically treated the inner <li></li> block within our foreach loop as an HTML content block because it saw the opening <li> tag sequence and knew that it couldn’t be valid C#. This particular technique – using tags to identify content blocks within code – is one of the key ingredients that makes Razor so clean and productive with scenarios involving HTML creation. Using @: to explicitly indicate the start of content Not all content container blocks start with a tag element tag, though, and there are scenarios where the Razor parser can’t implicitly detect a content block. Razor addresses this by enabling you to explicitly indicate the beginning of a line of content by using the @: character sequence within a code block. The @: sequence indicates that the line of content that follows should be treated as a content block: As a more practical example, the below snippet demonstrates how we could output a “(Out of Stock!)” message next to our product name if the product is out of stock: Because I am not wrapping the (Out of Stock!) message in an HTML tag element, Razor can’t implicitly determine that the content within the @if block is the start of a content block. We are using the @: character sequence to explicitly indicate that this line within our code block should be treated as content. Using Code Nuggets within @: content blocks In addition to outputting static content, you can also have code nuggets embedded within a content block that is initiated using a @: character sequence. For example, we have two @: sequences in the code snippet below: Notice how within the second @: sequence we are emitting the number of units left within the content block (e.g. - “(Only 3 left!”). We are doing this by embedding a @p.UnitsInStock code nugget within the line of content. Multiple Lines of Content Razor makes it easy to have multiple lines of content wrapped in an HTML element. For example, below the inner content of our @if container is wrapped in an HTML <p> element – which will cause Razor to treat it as content: For scenarios where the multiple lines of content are not wrapped by an outer HTML element, you can use multiple @: sequences: Alternatively, Razor also allows you to use a <text> element to explicitly identify content: The <text> tag is an element that is treated specially by Razor. It causes Razor to interpret the inner contents of the <text> block as content, and to not render the containing <text> tag element (meaning only the inner contents of the <text> element will be rendered – the tag itself will not). This makes it convenient when you want to render multi-line content blocks that are not wrapped by an HTML element. The <text> element can also optionally be used to denote single-lines of content, if you prefer it to the more concise @: sequence: The above code will render the same output as the @: version we looked at earlier. Razor will automatically omit the <text> wrapping element from the output and just render the content within it. Summary Razor enables a clean and concise templating syntax that enables a very fluid coding workflow. Razor’s smart detection of <tag> elements to identify the beginning of content regions is one of the reasons that the Razor approach works so well with HTML generation scenarios, and it enables you to avoid having to explicitly mark the beginning/ending of content regions in about 95% of if/else and foreach scenarios. Razor’s @: and <text> syntax can then be used for scenarios where you want to avoid using an HTML element within a code container block, and need to more explicitly denote a content region. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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ASP.NET Membership Provider Setup

- by Ben Griswold

In this screencast, Noah and I show you how to quickly get started with the ASP.NET Membership Provider. We’ll take you through basic features and setup and walk you through membership table creation with the ASP.NET SQL Server Wizard. I’ve written about the ASP.NET Membership Provider and setup before. If you missed the post, this introductory video may be for you. This is one of our first screencasts. If you have feedback, I’d love to hear it.

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User is trying to leave! Set at-least confirm alert on browser(tab) close event!!

- by kaushalparik27

This is something that might be annoying or irritating for end user. Obviously, It's impossible to prevent end user from closing the/any browser. Just think of this if it becomes possible!!!. That will be a horrible web world where everytime you will be attacked by sites and they will not allow to close your browser until you confirm your shopping cart and do the payment. LOL:) You need to open the task manager and might have to kill the running browser exe processes.Anyways; Jokes apart, but I have one situation where I need to alert/confirm from the user in any anyway when they try to close the browser or change the url. Think of this: You are creating a single page intranet asp.net application where your employee can enter/select their TDS/Investment Declarations and you wish to at-least ALERT/CONFIRM them if they are attempting to:[1] Close the Browser[2] Close the Browser Tab[3] Attempt to go some other site by Changing the urlwithout completing/freezing their declaration.So, Finally requirement is clear. I need to alert/confirm the user what he is going to do on above bulleted events. I am going to use window.onbeforeunload event to set the javascript confirm alert box to appear. <script language="JavaScript" type="text/javascript"> window.onbeforeunload = confirmExit; function confirmExit() { return "You are about to exit the system before freezing your declaration! If you leave now and never return to freeze your declaration; then they will not go into effect and you may lose tax deduction, Are you sure you want to leave now?"; } </script>See! you are halfway done!. So, every time browser unloads the page, above confirm alert causes to appear on front of user like below:By saying here "every time browser unloads the page"; I mean to say that whenever page loads or postback happens the browser onbeforeunload event will be executed. So, event a button submit or a link submit which causes page to postback would tend to execute the browser onbeforeunload event to fire!So, now the hurdle is how can we prevent the alert "Not to show when page is being postback" via any button/link submit? Answer is JQuery :)Idea is, you just need to set the script reference src to jQuery library and Set the window.onbeforeunload event to null when any input/link causes a page to postback.Below will be the complete code:<head runat="server"> <title></title> <script src="jquery.min.js" type="text/javascript"></script> <script language="JavaScript" type="text/javascript"> window.onbeforeunload = confirmExit; function confirmExit() { return "You are about to exit the system before freezing your declaration! If you leave now and never return to freeze your declaration; then they will not go into effect and you may lose tax deduction, Are you sure you want to leave now?"; } $(function() { $("a").click(function() { window.onbeforeunload = null; }); $("input").click(function() { window.onbeforeunload = null; }); }); </script></head><body> <form id="form1" runat="server"> <div></div> </form></body></html>So, By this post I have tried to set the confirm alert if user try to close the browser/tab or try leave the site by changing the url. I have attached a working example with this post here. I hope someone might find it helpful.

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How to access HTML elements from server side code in an asp.net website

- by nikolaosk

In this post I will demonstrate with a hands on example how HTML elements in an .aspx page can be processed exactly like standard ASP.Net server controls. Basically how to make them accessible from server side code. 1) Launch Visual Studio 2010/2008/2005. (express editions will work fine). Create a new empty website and choose a suitable name for it. Choose VB as the development language. 2) Add a new item in your site, a web form. Leave the default name. 3) Let's say that we want to change the background...(read more)

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Should a c# dev switch to VB.net when the team language base is mixed?

- by jjr2527

I recently joined a new development team where the language preferences are mixed on the .net platform. Dev 1: Knows VB.net, does not know c# Dev 2: Knows VB.net, does not know c# Dev 3: Knows c# and VB.net, prefers c# Dev 4: Knows c# and VB6(VB.net should be pretty easy to pick up), prefers c# It seems to me that the thought leaders in the .net space are c# devs almost universally. I also thought that some 3rd party tools didn't support VB.net but when I started looking into it I didn't find any good examples. I would prefer to get the whole team on c# but if there isn't any good reason to force the issue aside from preference then I don't think that is the right choice. Are there any reasons I should lead folks away from VB.net?

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Union,Except and Intersect operator in Linq

- by Jalpesh P. Vadgama

While developing a windows service using Linq-To-SQL i was in need of something that will intersect the two list and return a list with the result. After searching on net i have found three great use full operators in Linq Union,Except and Intersect. Here are explanation of each operator. Union Operator: Union operator will combine elements of both entity and return result as third new entities. Except Operator: Except operator will remove elements of first entities which elements are there in second entities and will return as third new entities. Intersect Operator: As name suggest it will return common elements of both entities and return result as new entities. Let’s take a simple console application as a example where i have used two string array and applied the three operator one by one and print the result using Console.Writeline. Here is the code for that. C#, using GeSHi 1.0.8.6 using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { string[] a = { "a", "b", "c", "d" }; string[] b = { "d","e","f","g"}; var UnResult = a.Union(b); Console.WriteLine("Union Result"); foreach (string s in UnResult) { Console.WriteLine(s); } var ExResult = a.Except(b); Console.WriteLine("Except Result"); foreach (string s in ExResult) { Console.WriteLine(s); } var InResult = a.Intersect(b); Console.WriteLine("Intersect Result"); foreach (string s in InResult) { Console.WriteLine(s); } Console.ReadLine(); } } } Parsed in 0.022 seconds at 45.54 KB/s Here is the output of console application as Expected. Hope this will help you.. Technorati Tags: Linq,Except,InterSect,Union,C#

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ASP.NET Web Forms Extensibility: Handler Factories

- by Ricardo Peres

An handler factory is the class that implements IHttpHandlerFactory and is responsible for instantiating an handler (IHttpHandler) that will process the current request. This is true for all kinds of web requests, whether they are for ASPX pages, ASMX/SVC web services, ASHX/AXD handlers, or any other kind of file. Also used for restricting access for certain file types, such as Config, Csproj, etc. Handler factories are registered on the global Web.config file, normally located at %WINDIR%\Microsoft.NET\Framework<x64>\vXXXX\Config for a given path and request type (GET, POST, HEAD, etc). This goes on section <httpHandlers>. You would create a custom handler factory for a number of reasons, let me list just two: A centralized place for using dependency injection; Also a centralized place for invoking custom methods or performing some kind of validation on all pages. Let’s see an example using Unity for injecting dependencies into a page, suppose we have this on Global.asax.cs: 1: public class Global : HttpApplication 2: { 3: internal static readonly IUnityContainer Unity = new UnityContainer(); 4: 5: void Application_Start(Object sender, EventArgs e) 6: { 7: Unity.RegisterType<IFunctionality, ConcreteFunctionality>(); 8: } 9: } We instantiate Unity and register a concrete implementation for an interface, this could/should probably go in the Web.config file. Forget about its actual definition, it’s not important. Then, we create a custom handler factory: 1: public class UnityPageHandlerFactory : PageHandlerFactory 2: { 3: public override IHttpHandler GetHandler(HttpContext context, String requestType, String virtualPath, String path) 4: { 5: IHttpHandler handler = base.GetHandler(context, requestType, virtualPath, path); 6: 7: //one scenario: inject dependencies 8: Global.Unity.BuildUp(handler.GetType(), handler, String.Empty); 9: 10: return (handler); 11: } 12: } It inherits from PageHandlerFactory, which is .NET’s included factory for building regular ASPX pages. We override the GetHandler method and issue a call to the BuildUp method, which will inject required dependencies, if any exist. An example page with dependencies might be: 1: public class SomePage : Page 2: { 3: [Dependency] 4: public IFunctionality Functionality 5: { 6: get; 7: set; 8: } 9: } Notice the DependencyAttribute, it is used by Unity to identify properties that require dependency injection. When BuildUp is called, the Functionality property (or any other properties with the DependencyAttribute attribute) will receive the concrete implementation associated with it’s type, as registered on Unity. Another example, checking a page for authorization. Let’s define an interface first: 1: public interface IRestricted 2: { 3: Boolean Check(HttpContext ctx); 4: } An a page implementing that interface: 1: public class RestrictedPage : Page, IRestricted 2: { 3: public Boolean Check(HttpContext ctx) 4: { 5: //check the context and return a value 6: return ...; 7: } 8: } For this, we would use an handler factory such as this: 1: public class RestrictedPageHandlerFactory : PageHandlerFactory 2: { 3: private static readonly IHttpHandler forbidden = new UnauthorizedHandler(); 4: 5: public override IHttpHandler GetHandler(HttpContext context, String requestType, String virtualPath, String path) 6: { 7: IHttpHandler handler = base.GetHandler(context, requestType, virtualPath, path); 8: 9: if (handler is IRestricted) 10: { 11: if ((handler as IRestricted).Check(context) == false) 12: { 13: return (forbidden); 14: } 15: } 16: 17: return (handler); 18: } 19: } 20: 21: public class UnauthorizedHandler : IHttpHandler 22: { 23: #region IHttpHandler Members 24: 25: public Boolean IsReusable 26: { 27: get { return (true); } 28: } 29: 30: public void ProcessRequest(HttpContext context) 31: { 32: context.Response.StatusCode = (Int32) HttpStatusCode.Unauthorized; 33: context.Response.ContentType = "text/plain"; 34: context.Response.Write(context.Response.Status); 35: context.Response.Flush(); 36: context.Response.Close(); 37: context.ApplicationInstance.CompleteRequest(); 38: } 39: 40: #endregion 41: } The UnauthorizedHandler is an example of an IHttpHandler that merely returns an error code to the client, but does not cause redirection to the login page, it is included merely as an example. One thing we must keep in mind is, there can be only one handler factory registered for a given path/request type (verb) tuple. A typical registration would be: 1: <httpHandlers> 2: <remove path="*.aspx" verb="*"/> 3: <add path="*.aspx" verb="*" type="MyNamespace.MyHandlerFactory, MyAssembly"/> 4: </httpHandlers> First we remove the previous registration for ASPX files, and then we register our own. And that’s it. A very useful mechanism which I use lots of times.

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Membership in ASP.Net applications - part 4

- by nikolaosk

This is the fourth post in a series of posts regarding ASP.Net built in membership functionality,providers,controls. You can read the first one here . You can read the second post here . You can read the third post here . In this post I will show you how to add users programmatically to a role. In the third post we saw how to get users in a specific role.I will also show you how to delete a user and a role programmatically. 1) Launch Visual Studio 2005,2008/2010. Express editions will work fine....(read more)

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Run the Windows .net Application in System Tray on System Startup

- by Rajneesh Verma

Hi, Today i have created a .net windows application which has following key points. 1. Run only one instance of the project: to achieve this i have change the code of Program.cs as: Code Snippet static class Program { /// <summary> /// The main entry point for the application. /// </summary> [ STAThread ] static void Main() { bool instanceCountOne = false ; using ( Mutex mtex = new Mutex ( true , "MyRunningApp" , out instanceCountOne)) { if (instanceCountOne) { Application ...(read more)

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Returning Images from ASP.NET Web API

- by bipinjoshi

Sometimes you need to save and retrieve image data in SQL Server as a part of Web API functionality. A common approach is to save images as physical image files on the web server and then store the image URL in a SQL Server database. However, at times you need to store image data directly into a SQL Server database rather than the image URL. While dealing with the later scenario you need to read images from a database and then return this image data from your Web API. This article shows the steps involved in this process. http://www.bipinjoshi.net/articles/4b9922c3-0982-4e8f-812c-488ff4dbd507.aspx

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LLBLGen Pro feature highlights: grouping model elements

- by FransBouma

(This post is part of a series of posts about features of the LLBLGen Pro system) When working with an entity model which has more than a few entities, it's often convenient to be able to group entities together if they belong to a semantic sub-model. For example, if your entity model has several entities which are about 'security', it would be practical to group them together under the 'security' moniker. This way, you could easily find them back, yet they can be left inside the complete entity model altogether so their relationships with entities outside the group are kept. In other situations your domain consists of semi-separate entity models which all target tables/views which are located in the same database. It then might be convenient to have a single project to manage the complete target database, yet have the entity models separate of each other and have them result in separate code bases. LLBLGen Pro can do both for you. This blog post will illustrate both situations. The feature is called group usage and is controllable through the project settings. This setting is supported on all supported O/R mapper frameworks. Situation one: grouping entities in a single model. This situation is common for entity models which are dense, so many relationships exist between all sub-models: you can't split them up easily into separate models (nor do you likely want to), however it's convenient to have them grouped together into groups inside the entity model at the project level. A typical example for this is the AdventureWorks example database for SQL Server. This database, which is a single catalog, has for each sub-group a schema, however most of these schemas are tightly connected with each other: adding all schemas together will give a model with entities which indirectly are related to all other entities. LLBLGen Pro's default setting for group usage is AsVisualGroupingMechanism which is what this situation is all about: we group the elements for visual purposes, it has no real meaning for the model nor the code generated. Let's reverse engineer AdventureWorks to an entity model. By default, LLBLGen Pro uses the target schema an element is in which is being reverse engineered, as the group it will be in. This is convenient if you already have categorized tables/views in schemas, like which is the case in AdventureWorks. Of course this can be switched off, or corrected on the fly. When reverse engineering, we'll walk through a wizard which will guide us with the selection of the elements which relational model data should be retrieved, which we can later on use to reverse engineer to an entity model. The first step after specifying which database server connect to is to select these elements. below we can see the AdventureWorks catalog as well as the different schemas it contains. We'll include all of them. After the wizard completes, we have all relational model data nicely in our catalog data, with schemas. So let's reverse engineer entities from the tables in these schemas. We select in the catalog explorer the schemas 'HumanResources', 'Person', 'Production', 'Purchasing' and 'Sales', then right-click one of them and from the context menu, we select Reverse engineer Tables to Entity Definitions.... This will bring up the dialog below. We check all checkboxes in one go by checking the checkbox at the top to mark them all to be added to the project. As you can see LLBLGen Pro has already filled in the group name based on the schema name, as this is the default and we didn't change the setting. If you want, you can select multiple rows at once and set the group name to something else using the controls on the dialog. We're fine with the group names chosen so we'll simply click Add to Project. This gives the following result: (I collapsed the other groups to keep the picture small ;)). As you can see, the entities are now grouped. Just to see how dense this model is, I've expanded the relationships of Employee: As you can see, it has relationships with entities from three other groups than HumanResources. It's not doable to cut up this project into sub-models without duplicating the Employee entity in all those groups, so this model is better suited to be used as a single model resulting in a single code base, however it benefits greatly from having its entities grouped into separate groups at the project level, to make work done on the model easier. Now let's look at another situation, namely where we work with a single database while we want to have multiple models and for each model a separate code base. Situation two: grouping entities in separate models within the same project. To get rid of the entities to see the second situation in action, simply undo the reverse engineering action in the project. We still have the AdventureWorks relational model data in the catalog. To switch LLBLGen Pro to see each group in the project as a separate project, open the Project Settings, navigate to General and set Group usage to AsSeparateProjects. In the catalog explorer, select Person and Production, right-click them and select again Reverse engineer Tables to Entities.... Again check the checkbox at the top to mark all entities to be added and click Add to Project. We get two groups, as expected, however this time the groups are seen as separate projects. This means that the validation logic inside LLBLGen Pro will see it as an error if there's e.g. a relationship or an inheritance edge linking two groups together, as that would lead to a cyclic reference in the code bases. To see this variant of the grouping feature, seeing the groups as separate projects, in action, we'll generate code from the project with the two groups we just created: select from the main menu: Project -> Generate Source-code... (or press F7 ;)). In the dialog popping up, select the target .NET framework you want to use, the template preset, fill in a destination folder and click Start Generator (normal). This will start the code generator process. As expected the code generator has simply generated two code bases, one for Person and one for Production: The group name is used inside the namespace for the different elements. This allows you to add both code bases to a single solution and use them together in a different project without problems. Below is a snippet from the code file of a generated entity class. //... using System.Xml.Serialization; using AdventureWorks.Person; using AdventureWorks.Person.HelperClasses; using AdventureWorks.Person.FactoryClasses; using AdventureWorks.Person.RelationClasses; using SD.LLBLGen.Pro.ORMSupportClasses; namespace AdventureWorks.Person.EntityClasses { //... /// <summary>Entity class which represents the entity 'Address'.<br/><br/></summary> [Serializable] public partial class AddressEntity : CommonEntityBase //... The advantage of this is that you can have two code bases and work with them separately, yet have a single target database and maintain everything in a single location. If you decide to move to a single code base, you can do so with a change of one setting. It's also useful if you want to keep the groups as separate models (and code bases) yet want to add relationships to elements from another group using a copy of the entity: you can simply reverse engineer the target table to a new entity into a different group, effectively making a copy of the entity. As there's a single target database, changes made to that database are reflected in both models which makes maintenance easier than when you'd have a separate project for each group, with its own relational model data. Conclusion LLBLGen Pro offers a flexible way to work with entities in sub-models and control how the sub-models end up in the generated code.

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Securing an ASP.NET MVC 2 Application

- by rajbk

This post attempts to look at some of the methods that can be used to secure an ASP.NET MVC 2 Application called Northwind Traders Human Resources. The sample code for the project is attached at the bottom of this post. We are going to use a slightly modified Northwind database. The screen capture from SQL server management studio shows the change. I added a new column called Salary, inserted some random salaries for the employees and then turned off AllowNulls. The reporting relationship for Northwind Employees is shown below. The requirements for our application are as follows: Employees can see their LastName, FirstName, Title, Address and Salary Employees are allowed to edit only their Address information Employees can see the LastName, FirstName, Title, Address and Salary of their immediate reports Employees cannot see records of non immediate reports. Employees are allowed to edit only the Salary and Title information of their immediate reports. Employees are not allowed to edit the Address of an immediate report Employees should be authenticated into the system. Employees by default get the “Employee” role. If a user has direct reports, they will also get assigned a “Manager” role. We use a very basic empId/pwd scheme of EmployeeID (1-9) and password test$1. You should never do this in an actual application. The application should protect from Cross Site Request Forgery (CSRF). For example, Michael could trick Steven, who is already logged on to the HR website, to load a page which contains a malicious request. where without Steven’s knowledge, a form on the site posts information back to the Northwind HR website using Steven’s credentials. Michael could use this technique to give himself a raise :-) UI Notes The layout of our app looks like so: When Nancy (EmpID 1) signs on, she sees the default page with her details and is allowed to edit her address. If Nancy attempts to view the record of employee Andrew who has an employeeID of 2 (Employees/Edit/2), she will get a “Not Authorized” error page. When Andrew (EmpID 2) signs on, he can edit the address field of his record and change the title and salary of employees that directly report to him. Implementation Notes All controllers inherit from a BaseController. The BaseController currently only has error handling code. When a user signs on, we check to see if they are in a Manager role. We then create a FormsAuthenticationTicket, encrypt it (including the roles that the employee belongs to) and add it to a cookie. private void SetAuthenticationCookie(int employeeID, List<string> roles) { HttpCookiesSection cookieSection = (HttpCookiesSection) ConfigurationManager.GetSection("system.web/httpCookies"); AuthenticationSection authenticationSection = (AuthenticationSection) ConfigurationManager.GetSection("system.web/authentication"); FormsAuthenticationTicket authTicket = new FormsAuthenticationTicket( 1, employeeID.ToString(), DateTime.Now, DateTime.Now.AddMinutes(authenticationSection.Forms.Timeout.TotalMinutes), false, string.Join("|", roles.ToArray())); String encryptedTicket = FormsAuthentication.Encrypt(authTicket); HttpCookie authCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket); if (cookieSection.RequireSSL || authenticationSection.Forms.RequireSSL) { authCookie.Secure = true; } HttpContext.Current.Response.Cookies.Add(authCookie); } We read this cookie back in Global.asax and set the Context.User to be a new GenericPrincipal with the roles we assigned earlier. protected void Application_AuthenticateRequest(Object sender, EventArgs e){ if (Context.User != null) { string cookieName = FormsAuthentication.FormsCookieName; HttpCookie authCookie = Context.Request.Cookies[cookieName]; if (authCookie == null) return; FormsAuthenticationTicket authTicket = FormsAuthentication.Decrypt(authCookie.Value); string[] roles = authTicket.UserData.Split(new char[] { '|' }); FormsIdentity fi = (FormsIdentity)(Context.User.Identity); Context.User = new System.Security.Principal.GenericPrincipal(fi, roles); }} We ensure that a user has permissions to view a record by creating a custom attribute AuthorizeToViewID that inherits from ActionFilterAttribute. public class AuthorizeToViewIDAttribute : ActionFilterAttribute{ IEmployeeRepository employeeRepository = new EmployeeRepository(); public override void OnActionExecuting(ActionExecutingContext filterContext) { if (filterContext.ActionParameters.ContainsKey("id") && filterContext.ActionParameters["id"] != null) { if (employeeRepository.IsAuthorizedToView((int)filterContext.ActionParameters["id"])) { return; } } throw new UnauthorizedAccessException("The record does not exist or you do not have permission to access it"); }} We add the AuthorizeToView attribute to any Action method that requires authorization. [HttpPost][Authorize(Order = 1)]//To prevent CSRF[ValidateAntiForgeryToken(Salt = Globals.EditSalt, Order = 2)]//See AuthorizeToViewIDAttribute class[AuthorizeToViewID(Order = 3)] [ActionName("Edit")]public ActionResult Update(int id){ var employeeToEdit = employeeRepository.GetEmployee(id); if (employeeToEdit != null) { //Employees can edit only their address //A manager can edit the title and salary of their subordinate string[] whiteList = (employeeToEdit.IsSubordinate) ? new string[] { "Title", "Salary" } : new string[] { "Address" }; if (TryUpdateModel(employeeToEdit, whiteList)) { employeeRepository.Save(employeeToEdit); return RedirectToAction("Details", new { id = id }); } else { ModelState.AddModelError("", "Please correct the following errors."); } } return View(employeeToEdit);} The Authorize attribute is added to ensure that only authorized users can execute that Action. We use the TryUpdateModel with a white list to ensure that (a) an employee is able to edit only their Address and (b) that a manager is able to edit only the Title and Salary of a subordinate. This works in conjunction with the AuthorizeToViewIDAttribute. The ValidateAntiForgeryToken attribute is added (with a salt) to avoid CSRF. The Order on the attributes specify the order in which the attributes are executed. The Edit View uses the AntiForgeryToken helper to render the hidden token: ......<% using (Html.BeginForm()) {%><%=Html.AntiForgeryToken(NorthwindHR.Models.Globals.EditSalt)%><%= Html.ValidationSummary(true, "Please correct the errors and try again.") %><div class="editor-label"> <%= Html.LabelFor(model => model.LastName) %></div><div class="editor-field">...... The application uses View specific models for ease of model binding. public class EmployeeViewModel{ public int EmployeeID; [Required] [DisplayName("Last Name")] public string LastName { get; set; } [Required] [DisplayName("First Name")] public string FirstName { get; set; } [Required] [DisplayName("Title")] public string Title { get; set; } [Required] [DisplayName("Address")] public string Address { get; set; } [Required] [DisplayName("Salary")] [Range(500, double.MaxValue)] public decimal Salary { get; set; } public bool IsSubordinate { get; set; }} To help with displaying readonly/editable fields, we use a helper method. //Simple extension method to display a TextboxFor or DisplayFor based on the isEditable variablepublic static MvcHtmlString TextBoxOrLabelFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, bool isEditable){ if (isEditable) { return htmlHelper.TextBoxFor(expression); } else { return htmlHelper.DisplayFor(expression); }} The helper method is used in the view like so: <%=Html.TextBoxOrLabelFor(model => model.Title, Model.IsSubordinate)%> As mentioned in this post, there is a much easier way to update properties on an object. Download Demo Project VS 2008, ASP.NET MVC 2 RTM Remember to change the connectionString to point to your Northwind DB NorthwindHR.zip Feedback and bugs are always welcome :-)

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ASP.NET MVC 3: Implicit and Explicit code nuggets with Razor

- by ScottGu

This is another in a series of posts I’m doing that cover some of the new ASP.NET MVC 3 features: New @model keyword in Razor (Oct 19th) Layouts with Razor (Oct 22nd) Server-Side Comments with Razor (Nov 12th) Razor’s @: and <text> syntax (Dec 15th) Implicit and Explicit code nuggets with Razor (today) In today’s post I’m going to discuss how Razor enables you to both implicitly and explicitly define code nuggets within your view templates, and walkthrough some code examples of each of them. Fluid Coding with Razor ASP.NET MVC 3 ships with a new view-engine option called “Razor” (in addition to the existing .aspx view engine). You can learn more about Razor, why we are introducing it, and the syntax it supports from my Introducing Razor blog post. Razor minimizes the number of characters and keystrokes required when writing a view template, and enables a fast, fluid coding workflow. Unlike most template syntaxes, you do not need to interrupt your coding to explicitly denote the start and end of server blocks within your HTML. The Razor parser is smart enough to infer this from your code. This enables a compact and expressive syntax which is clean, fast and fun to type. For example, the Razor snippet below can be used to iterate a collection of products and output a <ul> list of product names that link to their corresponding product pages: When run, the above code generates output like below: Notice above how we were able to embed two code nuggets within the content of the foreach loop. One of them outputs the name of the Product, and the other embeds the ProductID within a hyperlink. Notice that we didn’t have to explicitly wrap these code-nuggets - Razor was instead smart enough to implicitly identify where the code began and ended in both of these situations. How Razor Enables Implicit Code Nuggets Razor does not define its own language. Instead, the code you write within Razor code nuggets is standard C# or VB. This allows you to re-use your existing language skills, and avoid having to learn a customized language grammar. The Razor parser has smarts built into it so that whenever possible you do not need to explicitly mark the end of C#/VB code nuggets you write. This makes coding more fluid and productive, and enables a nice, clean, concise template syntax. Below are a few scenarios that Razor supports where you can avoid having to explicitly mark the beginning/end of a code nugget, and instead have Razor implicitly identify the code nugget scope for you: Property Access Razor allows you to output a variable value, or a sub-property on a variable that is referenced via “dot” notation: You can also use “dot” notation to access sub-properties multiple levels deep: Array/Collection Indexing: Razor allows you to index into collections or arrays: Calling Methods: Razor also allows you to invoke methods: Notice how for all of the scenarios above how we did not have to explicitly end the code nugget. Razor was able to implicitly identify the end of the code block for us. Razor’s Parsing Algorithm for Code Nuggets The below algorithm captures the core parsing logic we use to support “@” expressions within Razor, and to enable the implicit code nugget scenarios above: Parse an identifier - As soon as we see a character that isn't valid in a C# or VB identifier, we stop and move to step 2 Check for brackets - If we see "(" or "[", go to step 2.1., otherwise, go to step 3 Parse until the matching ")" or "]" (we track nested "()" and "[]" pairs and ignore "()[]" we see in strings or comments) Go back to step 2 Check for a "." - If we see one, go to step 3.1, otherwise, DO NOT ACCEPT THE "." as code, and go to step 4 If the character AFTER the "." is a valid identifier, accept the "." and go back to step 1, otherwise, go to step 4 Done! Differentiating between code and content Step 3.1 is a particularly interesting part of the above algorithm, and enables Razor to differentiate between scenarios where an identifier is being used as part of the code statement, and when it should instead be treated as static content: Notice how in the snippet above we have ? and ! characters at the end of our code nuggets. These are both legal C# identifiers – but Razor is able to implicitly identify that they should be treated as static string content as opposed to being part of the code expression because there is whitespace after them. This is pretty cool and saves us keystrokes. Explicit Code Nuggets in Razor Razor is smart enough to implicitly identify a lot of code nugget scenarios. But there are still times when you want/need to be more explicit in how you scope the code nugget expression. The @(expression) syntax allows you to do this: You can write any C#/VB code statement you want within the @() syntax. Razor will treat the wrapping () characters as the explicit scope of the code nugget statement. Below are a few scenarios where we could use the explicit code nugget feature: Perform Arithmetic Calculation/Modification: You can perform arithmetic calculations within an explicit code nugget: Appending Text to a Code Expression Result: You can use the explicit expression syntax to append static text at the end of a code nugget without having to worry about it being incorrectly parsed as code: Above we have embedded a code nugget within an <img> element’s src attribute. It allows us to link to images with URLs like “/Images/Beverages.jpg”. Without the explicit parenthesis, Razor would have looked for a “.jpg” property on the CategoryName (and raised an error). By being explicit we can clearly denote where the code ends and the text begins. Using Generics and Lambdas Explicit expressions also allow us to use generic types and generic methods within code expressions – and enable us to avoid the <> characters in generics from being ambiguous with tag elements. One More Thing….Intellisense within Attributes We have used code nuggets within HTML attributes in several of the examples above. One nice feature supported by the Razor code editor within Visual Studio is the ability to still get VB/C# intellisense when doing this. Below is an example of C# code intellisense when using an implicit code nugget within an <a> href=”” attribute: Below is an example of C# code intellisense when using an explicit code nugget embedded in the middle of a <img> src=”” attribute: Notice how we are getting full code intellisense for both scenarios – despite the fact that the code expression is embedded within an HTML attribute (something the existing .aspx code editor doesn’t support). This makes writing code even easier, and ensures that you can take advantage of intellisense everywhere. Summary Razor enables a clean and concise templating syntax that enables a very fluid coding workflow. Razor’s ability to implicitly scope code nuggets reduces the amount of typing you need to perform, and leaves you with really clean code. When necessary, you can also explicitly scope code expressions using a @(expression) syntax to provide greater clarity around your intent, as well as to disambiguate code statements from static markup. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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Presentation: ASP.NET Ajax Library at Southern California .NET Architecture User Group

- by craigshoemaker

Big thanks to Mike Vincent and David Wells of the Southern California .NET Architecture User Group for inviting me to speak this evening! If you are looking for the code and the slides you can download them here.

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Persisting model state in ASP.NET MVC using Serialize HTMLHelper

- by shiju

ASP.NET MVC 2 futures assembly provides a HTML helper method Serialize that can be use for persisting your model object. The Serialize helper method will serialize the model object and will persist it in a hidden field in the HTML form. The Serialize helper is very useful when situations like you are making multi-step wizard where a single model class is using for all steps in the wizard. For each step you want to retain the model object's whole state.The below is serializing our model object. The model object should be a Serializable class in order to work with Serialize helper method. <% using (Html.BeginForm("Register","User")) {%><%= Html.Serialize("User",Model) %> This will generate hidden field with name "user" and the value will the serialized format of our model object.In the controller action, you can place the DeserializeAttribute in the action method parameter. [HttpPost] public ActionResult Register([DeserializeAttribute] User user, FormCollection userForm) { TryUpdateModel(user, userForm.ToValueProvider()); //To Do } In the above action method you will get the same model object that you serialized in your view template. We are updating the User model object with the form field values.

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Persisting model state in ASP.NET MVC using Serialize HTMLHelper

- by shiju

ASP.NET MVC 2 futures assembly provides a HTML helper method Serialize that can be use for persisting your model object. The Serialize helper method will serialize the model object and will persist it in a hidden field in the HTML form. The Serialize helper is very useful when situations like you are making multi-step wizard where a single model class is using for all steps in the wizard. For each step you want to retain the model object's whole state.The below is serializing our model object. The model object should be a Serializable class in order to work with Serialize helper method. <% using (Html.BeginForm("Register","User")) {%><%= Html.Serialize("User",Model) %> This will generate hidden field with name "user" and the value will the serialized format of our model object.In the controller action, you can place the DeserializeAttribute in the action method parameter. [HttpPost] public ActionResult Register([DeserializeAttribute] User user, FormCollection userForm) { TryUpdateModel(user, userForm.ToValueProvider()); //To Do } In the above action method you will get the same model object that you serialized in your view template. We are updating the User model object with the form field values.

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ASP.NET MVC ‘Extendable-hooks’ – ControllerActionInvoker class

- by nmarun

There’s a class ControllerActionInvoker in ASP.NET MVC. This can be used as one of an hook-points to allow customization of your application. Watching Brad Wilsons’ Advanced MP3 from MVC Conf inspired me to write about this class. What MSDN says: “Represents a class that is responsible for invoking the action methods of a controller.” Well if MSDN says it, I think I can instill a fair amount of confidence into what the class does. But just to get to the details, I also looked into the source code for MVC. Seems like the base class Controller is where an IActionInvoker is initialized: 1: protected virtual IActionInvoker CreateActionInvoker() { 2: return new ControllerActionInvoker(); 3: } In the ControllerActionInvoker (the O-O-B behavior), there are different ‘versions’ of InvokeActionMethod() method that actually call the action method in question and return an instance of type ActionResult. 1: protected virtual ActionResult InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters) { 2: object returnValue = actionDescriptor.Execute(controllerContext, parameters); 3: ActionResult result = CreateActionResult(controllerContext, actionDescriptor, returnValue); 4: return result; 5: } I guess that’s enough on the ‘behind-the-screens’ of this class. Let’s see how we can use this class to hook-up extensions. Say I have a requirement that the user should be able to get different renderings of the same output, like html, xml, json, csv and so on. The user will type-in the output format in the url and should the get result accordingly. For example: http://site.com/RenderAs/ – renders the default way (the razor view) http://site.com/RenderAs/xml http://site.com/RenderAs/csv … and so on where RenderAs is my controller. There are many ways of doing this and I’m using a custom ControllerActionInvoker class (even though this might not be the best way to accomplish this). For this, my one and only route in the Global.asax.cs is: 1: routes.MapRoute("RenderAsRoute", "RenderAs/{outputType}", 2: new {controller = "RenderAs", action = "Index", outputType = ""}); Here the controller name is ‘RenderAsController’ and the action that’ll get called (always) is the Index action. The outputType parameter will map to the type of output requested by the user (xml, csv…). I intend to display a list of food items for this example. 1: public class Item 2: { 3: public int Id { get; set; } 4: public string Name { get; set; } 5: public Cuisine Cuisine { get; set; } 6: } 7: 8: public class Cuisine 9: { 10: public int CuisineId { get; set; } 11: public string Name { get; set; } 12: } Coming to my ‘RenderAsController’ class. I generate an IList<Item> to represent my model. 1: private static IList<Item> GetItems() 2: { 3: Cuisine cuisine = new Cuisine { CuisineId = 1, Name = "Italian" }; 4: Item item = new Item { Id = 1, Name = "Lasagna", Cuisine = cuisine }; 5: IList<Item> items = new List<Item> { item }; 6: item = new Item {Id = 2, Name = "Pasta", Cuisine = cuisine}; 7: items.Add(item); 8: //... 9: return items; 10: } My action method looks like 1: public IList<Item> Index(string outputType) 2: { 3: return GetItems(); 4: } There are two things that stand out in this action method. The first and the most obvious one being that the return type is not of type ActionResult (or one of its derivatives). Instead I’m passing the type of the model itself (IList<Item> in this case). We’ll convert this to some type of an ActionResult in our custom controller action invoker class later. The second thing (a little subtle) is that I’m not doing anything with the outputType value that is passed on to this action method. This value will be in the RouteData dictionary and we’ll use this in our custom invoker class as well. It’s time to hook up our invoker class. First, I’ll override the Initialize() method of my RenderAsController class. 1: protected override void Initialize(RequestContext requestContext) 2: { 3: base.Initialize(requestContext); 4: string outputType = string.Empty; 5: 6: // read the outputType from the RouteData dictionary 7: if (requestContext.RouteData.Values["outputType"] != null) 8: { 9: outputType = requestContext.RouteData.Values["outputType"].ToString(); 10: } 11: 12: // my custom invoker class 13: ActionInvoker = new ContentRendererActionInvoker(outputType); 14: } Coming to the main part of the discussion – the ContentRendererActionInvoker class: 1: public class ContentRendererActionInvoker : ControllerActionInvoker 2: { 3: private readonly string _outputType; 4: 5: public ContentRendererActionInvoker(string outputType) 6: { 7: _outputType = outputType.ToLower(); 8: } 9: //... 10: } So the outputType value that was read from the RouteData, which was passed in from the url, is being set here in a private field. Moving to the crux of this article, I now override the CreateActionResult method. 1: protected override ActionResult CreateActionResult(ControllerContext controllerContext, ActionDescriptor actionDescriptor, object actionReturnValue) 2: { 3: if (actionReturnValue == null) 4: return new EmptyResult(); 5: 6: ActionResult result = actionReturnValue as ActionResult; 7: if (result != null) 8: return result; 9: 10: // This is where the magic happens 11: // Depending on the value in the _outputType field, 12: // return an appropriate ActionResult 13: switch (_outputType) 14: { 15: case "json": 16: { 17: JavaScriptSerializer serializer = new JavaScriptSerializer(); 18: string json = serializer.Serialize(actionReturnValue); 19: return new ContentResult { Content = json, ContentType = "application/json" }; 20: } 21: case "xml": 22: { 23: XmlSerializer serializer = new XmlSerializer(actionReturnValue.GetType()); 24: using (StringWriter writer = new StringWriter()) 25: { 26: serializer.Serialize(writer, actionReturnValue); 27: return new ContentResult { Content = writer.ToString(), ContentType = "text/xml" }; 28: } 29: } 30: case "csv": 31: controllerContext.HttpContext.Response.AddHeader("Content-Disposition", "attachment; filename=items.csv"); 32: return new ContentResult 33: { 34: Content = ToCsv(actionReturnValue as IList<Item>), 35: ContentType = "application/ms-excel" 36: }; 37: case "pdf": 38: string filePath = controllerContext.HttpContext.Server.MapPath("~/items.pdf"); 39: controllerContext.HttpContext.Response.AddHeader("content-disposition", 40: "attachment; filename=items.pdf"); 41: ToPdf(actionReturnValue as IList<Item>, filePath); 42: return new FileContentResult(StreamFile(filePath), "application/pdf"); 43: 44: default: 45: controllerContext.Controller.ViewData.Model = actionReturnValue; 46: return new ViewResult 47: { 48: TempData = controllerContext.Controller.TempData, 49: ViewData = controllerContext.Controller.ViewData 50: }; 51: } 52: } A big method there! The hook I was talking about kinda above actually is here. This is where different kinds / formats of output get returned based on the output type requested in the url. When the _outputType is not set (string.Empty as set in the Global.asax.cs file), the razor view gets rendered (lines 45-50). This is the default behavior in most MVC applications where-in a view (webform/razor) gets rendered on the browser. As you see here, this gets returned as a ViewResult. But then, for an outputType of json/xml/csv, a ContentResult gets returned, while for pdf, a FileContentResult is returned. Here are how the different kinds of output look like: This is how we can leverage this feature of ASP.NET MVC to developer a better application. I’ve used the iTextSharp library to convert to a pdf format. Mike gives quite a bit of detail regarding this library here. You can download the sample code here. (You’ll get an option to download once you open the link). Verdict: Hot chocolate: $3; Reebok shoes: $50; Your first car: $3000; Being able to extend a web application: Priceless.

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Inline Image in ASP.NET

- by Ricardo Peres

Inline images is a technique that, instead of referring to an external URL, includes all of the image’s content in the HTML itself, in the form of a Base64-encoded string. It avoids a second browser request, at the cost of making the HTML page slightly heavier and not using cache. Not all browsers support it, but current versions of IE, Firefox and Chrome do. In order to use inline images, you must write the img element’s src attribute like this: 1: <img src="data:image/gif;base64,R0lGODlhEAAOALMAAOazToeHh0tLS/7LZv/0jvb29t/f3//Ub/ 2: /ge8WSLf/rhf/3kdbW1mxsbP//mf///yH5BAAAAAAALAAAAAAQAA4AAARe8L1Ekyky67QZ1hLnjM5UUde0ECwLJoExKcpp 3: V0aCcGCmTIHEIUEqjgaORCMxIC6e0CcguWw6aFjsVMkkIr7g77ZKPJjPZqIyd7sJAgVGoEGv2xsBxqNgYPj/gAwXEQA7" 4: width="16" height="14" alt="embedded folder icon"/> The syntax is: data:[<mediatype>][;base64],<data> I developed a simple control that allows you to use inline images in your ASP.NET pages. Here it is: 1: public class InnerImage: Image 2: { 3: protected override void OnInit(EventArgs e) 4: { 5: String imagePath = this.Context.Server.MapPath(this.ImageUrl); 6: String extension = Path.GetExtension(imagePath).Substring(1); 7: Byte[] imageData = File.ReadAllBytes(imagePath); 8: 9: this.ImageUrl = String.Format("data:image/{0};base64,{1}", extension, Convert.ToBase64String(imageData)); 10: 11: base.OnInit(e); 12: } 13: } Simple, don’t you think?

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