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  • Customized Computer Science Degree - What other field would mesh well with computer science?

    - by sailtheworld
    So here's my situation: I have seven years of experience with web development. I can do PHP, MySQL, OOP, all of that stuff. I would like to make the argument that I have enough technical experience to go out in the real world and get a well-paying, full-time job if I were to drop out right now (I've had a number of job offers recently, and I have already gotten a lot of actual job experience), but I would like to stay in school and get a degree for a number of reasons ranging from the social aspects to the fact that I just want to have a BS in one thing or another as it seems to be important to have one for a lot of jobs, even when it doesn't have anything to do with the job. With that said, it makes little sense for me to major in Computer Science, because that would be like studying everything I already know. I don't want to major in something COMPLETELY different, because that would be contrary to my career goals. I am considering trying to find some interdisciplinary, customized degree of sorts that allows me to combine my current skills with a new education. I'm thinking maybe buisness or even psychology (interface design?). Could I get some ideas for what to major in and tips on who I might talk to? Thanks!

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  • How can i compare Audio, what programming language should i use

    - by Pimmetje
    I have 2 audio files that are from almost the same source. But at some points there shifted a bit. Also the codecs does not match. I would like to make a program that takes a sample 2 - 4 seconds. And looks for it in the other file. (Most of the time it's not shifted more than 30 seconds). Than take the time and store it, Go ahead for a few seconds take a sample and find it again. This way i want to create a file where i can see on what points the file is shifted. For people who are more interested in what i want. I have a audio/video file speech and subtitles. But i have same speech from different sources with differs a bit in time. And i like to make a program that can correct the subtitle time for me. Enough about the problem I looked on the Internet for ways to compare audio files. Based on what i read comparing 2 audio files isn't that easy as i had hoped. Some talk about algorithms http://www.perlmonks.org/?node_id=169641 Some audio-library's portaudio.com aubio.org sourceforge.net/projects/ccaudio/ ambiera.com/irrklang/ The biggest problem i have is that i can't find something i can generate from the audio that i can use to compare with. I hope someone here can point me in the right direction.

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  • What's the best way to use requestAnimationFrame and fixed frame rates

    - by m90
    I recently got into using the HTML5-requestAnimationFrame-API a lot on animation-heavy websites, especially after seeing the Jank Busters talk. This seems to work pretty well and really improve performance in many cases. Yet one question still persists for me: When wanting to use an animation that is NOT entirely calculated (think spritesheets for example) you will have to aim for a fixed frame rate. Of course one could go back to use setInterval again, but maybe there are other ways to tackle this. The two ways I could think of using requestAnimationFrame with a fixed frame rate are: var fps = 25; //frames per second function animate(){ //actual drawing goes here setTimeout(function(){ requestAnimationFrame(animate); }, 1000 / fps) } animate(); or var fps = 25; //frames per second var lastExecution = new Date().getTime(); function animate(){ var now = new Date().getTime(); if ((now - lastExecution) > (1000 / fps)){ //do actual drawing lastExecution = new Date().getTime(); } requestAnimationFrame(animate); } animate(); Personally, I'd opt for the second option (the first one feels like cheating), yet it seems to be more buggy in certain situations. Is this approach really worth it (especially at low frame rates like 12.5)? Are there things to be improved? Is there another way to tackle this?

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  • Recommended display/background brightness ratio and UI color schemes [duplicate]

    - by user1306322
    This question already has an answer here: Colour scheme for editor - guidelines or medical reccomendations 3 answers I'm a professional programmer, which means I spend a lot of time staring at various displays. Recently I've been having some problems with my eyes, so I went to talk to several doctors, which all gave me different recommendations as to how bright the background of the room should be in comparison to the display's brightness. It was very confusing, as some of them even agreed with counter-arguments of others, which made it all even less clear. So I'd like to ask the professional programmers, as people who actually have some experience with that. Some of the doctors said that looking at a monitor is like looking at a book, so the brightness ratios should be approximately the same. Others said that background should be as bright as the display itself, because then there is no brightness difference at the edges, and that's what may cause eye fatigue. From my own experience, I can say that reading a book isn't the same as writing or debugging a program, where you have to pay close attention to each symbol, and in books most words are easily recognizable without focusing too hard on them. Also, books are black on white and I myself use the default (dark text, white bg) color scheme for my IDE, but I've seen some programmers use mid-bright text on very dark background color schemes. So I'd like to ask what are the recommended display/background brightness ratios for programming? I'm not sure this site is the right one for this kind of questions, so if you know a better one, please comment.

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  • What service or software should I use to serve advertising on a site with about 120k monthly page views?

    - by JasonBirch
    I have a site that is generating about 120k monthly page views and is being hosted on a shared FreeBSD server where I have access to PHP and MySQL. I am using some custom PHP server-side scripts that give each of my ad networks (AdSense, Tribal Fusion, etc) an adjustable percentage of impressions in each of the ad positions on my pages. I am looking for a better way of managing and measuring the delivery of these ads, and would also like to be able to take direct placements and provide statistics to the clients. I am looking at options including OpenX self-hosted, OpenX community, and Google DoubleClick for Publishers Small Business (DFP), but am having difficulty determining which one will best meet my needs. They all seem to have pretty steep learning curves compared to my simple scripts. What I have taken away so far as the benefit of self-hosting is that I don't have to pay for the service if I exceed a maximum number of ad impressions, while both OpenX Community and DFP have free impression limits. Of course, if I was doing those kind of numbers I'd need to upgrade my hosting account, but I'm not sure even at that point whether it would be cheaper to serve the ads myself than pay for a premium service. Apart from this, I really need insights into what features differentiate these services, why I might want to choose one over another, and if there are any other competing products or service of the same quality that I should look into. Answers from webmasters who have used both (or all three) services and can talk to usability and ease of ad management would be highly appreciated.

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  • Upon Reflection

    - by foxjazz
    During my tenure at the last company, I didn't let my career stagnate as others have and as time moved along.When at work or home, spend 10% of your time learning something new about some aspect or segway of your job so that your skills are marketable in case you lose it. From experience let me reinforce that it pays off. It pays off in your current job because of the education received and the competence increase of your skills which applied will bring recognition.In these days and times, loyalty to a company is truly at an end. However many companies do care about cultivating their employees which creates a brand of loyalty that can't be replaced. Old companies with the Corp. mentality (or because of the corp. mentality) ever decrease their budgets on organizational sections and thereby do a RIF as a matter of business.The mistakes they make during this process can be risky. But who am I, but a lowly ole programmer, to judge risk. If you are laid off, be friendly with your past manager, and based on simple questions and help, give whatever help you can over the phone even though you are under no obligation to do so.It is also quite possible that there are opportunities to make at home with a new company in the future. Just remember that when inquiring about a position, take advantage of the training that is offered, and keep yourself emotionally and educationally fit.Talk soon,foxjazz

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  • 2012 Oracle Fusion Innovation Awards - Part 1

    - by Michelle Kimihira
    Author: Moazzam Chaudry This year we recognized 29 customers for their innovative use of Oracle Fusion Middleware and their significant results. The winners were selected across 8 product categories from 11 countries spanning diverse industries around the world. This is a two-part blog series. The 2012 Fusion Middleware Innovation Awards winners were announced at OOW on October 2nd by Hasan Rizvi (EVP Fusion Middleware and Java development), Amit Zavery (VP Product Management) and Ed Zou (VP Product Management) to an audience that included press, analysts and customers. Winners were selected based on the uniqueness of their business case, business benefits, level of impact relative to the size of the organization, complexity and magnitude of implementation, and the originality of architecture. The program is in its 6th year and this year, we are excited to have received over 250 submissions from customers around the globe. The winners were selected by a panel of internal and external judges; it was a difficult time selecting this year's most innovative projects. Judges scored each entry across multiple scoring categories. This year, winning use cases for Fusion Middleware include: Improve customer experience by monitoring real-time and simplifying user experience of tens of millions of customer Drive social enagement through social media channels in fields, including healthcare, harness big data by analyzing and improving visibility across 60M+customers and hundreds of terabytes of data Enable mobile adoption by delivering mobile news experience to 50% of the Australian population, embrace cloud computing by delivering hospitality services to 3000+ hotels and monitoring services to hospitals, and optimize criticial processes such as, remarketing cars through tens of thousands of dealers On Monday's blog, we will talk about the winners in each category and what customers had to say in the customer panel. Congratulations to the 2012 Oracle Fusion Innovation Award winners:  

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  • JCP 2.9 and Transparency Call for Spec Leads 9 November

    - by heathervc
    JCP Spec Leads are invited to participate in an online meeting/call this Friday, 9 November, to hear a talk about the the 2.9 version of the Java Community Process (effective date of 13 November) and discuss the changes with representatives of the Program Management Office.  This call will be recorded and published with materials for those not able to attend.  Details of the call are included below.JCP 2.9 is presented in two documents:The JCP 2.9 document:http://www.jcp.org/en/procedures/jcp2and the EC Standing Rules document:http://www.jcp.org/en/procedures/ec_standing_rulesIn addition, we will be reviewing ways to collect community feedback on the transparency requirements for JCP 2.7 and above JSRs (JCP 2.8, JCP 2.9), detailed as part of the Spec Lead Guide.Call details:Topic: JCP 2.9 and Transparency Date: Friday, November 9, 2012 Time: 9:00 am, Pacific Standard Time (San Francisco, GMT-08:00) Meeting Number: 800 623 574 Meeting Password: 5282 ------------------------------------------------------- To start or join the online meeting ------------------------------------------------------- Go to https://jcp.webex.com/jcp/j.php?ED=188925347&UID=491098062&PW=NMDZiYTQzZmE1&RT=MiM0 ------------------------------------------------------- Audio conference information ------------------------------------------------------- Toll-Free Dial-In Number:     866 682-4770 International (Toll) Dial-In Number:     408 774-4073 Conference code 9454597 Security code 1020 Outside the US: global access numbers   https://www.intercallonline.com/portlets/scheduling/viewNumbers/listNumbersByCode.do?confCode=6279803

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  • Pros and Cons of Facebook's React vs. Web Components (Polymer)

    - by CletusW
    What are the main benefits of Facebook's React over the upcoming Web Components spec and vice versa (or perhaps a more apples-to-apples comparison would be to Google's Polymer library)? According to this JSConf EU talk and the React homepage, the main benefits of React are: Decoupling and increased cohesion using a component model Abstraction, Composition and Expressivity Virtual DOM & Synthetic events (which basically means they completely re-implemented the DOM and its event system) Enables modern HTML5 event stuff on IE 8 Server-side rendering Testability Bindings to SVG, VML, and <canvas> Almost everything mentioned is being integrated into browsers natively through Web Components except this virtual DOM concept (obviously). I can see how the virtual DOM and synthetic events can be beneficial today to support old browsers, but isn't throwing away a huge chunk of native browser code kind of like shooting yourself in the foot in the long term? As far as modern browsers are concerned, isn't that a lot of unnecessary overhead/reinventing of the wheel? Here are some things I think React is missing that Web Components will care of. Correct me if I'm wrong. Native browser support (read "guaranteed to be faster") Write script in a scripting language, write styles in a styling language, write markup in a markup language. Style encapsulation using Shadow DOM React instead has this, which requires writing CSS in JavaScript. Not pretty. Two-way binding

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  • Software Architecture: How to divide work to a network of computers?

    - by Morpork
    Imagine a scenario as follows: Lets say you have a central computer which generates a lot of data. This data must go through some processing, which unfortunately takes longer than to generate. In order for the processing to catch up with real time, we plug in more slave computers. Further, we must take into account the possibility of slaves dropping out of the network mid-job as well as additional slaves being added. The central computer should ensure that all jobs are finished to its satisfaction, and that jobs dropped by a slave are retasked to another. The main question is: What approach should I use to achieve this? But perhaps the following would help me arrive at an answer: Is there a name or design pattern to what I am trying to do? What domain of knowledge do I need to achieve the goal of getting these computers to talk to each other? (eg. will a database, which I have some knowledge of, be enough or will this involve sockets, which I have yet to have knowledge of?) Are there any examples of such a system? The main question is a bit general so it would be good to have a starting point/reference point. Note I am assuming constraints of c++ and windows so solutions pointing in that direction would be appreciated.

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  • Mobile (Client) to Amazon S3 (Server) - Architecture

    - by wasabii
    let's start off with the problem statement: My iOS application has a login form. When the user logs in, a call is made to my API and access granted or denied. If access was granted, I want the user to be able to upload pictures to his account and/or manage them. As storage I've picked Amazon S3, and I figured it'd be a good idea to have one bucket called "myappphotos" for instance, which contains lots of folders. The folder names are hashes of a user's email and a secret key. So, every user has his own, unique folder in my Amazon S3 bucket. Since I've just recently started working with AWS, here's my question: What are the best practices for setting up a system like this? I want the user to be able to upload pictures directly to Amazon S3, but of course I cannot hard-code the access key. So I need my API to somehow talk to Amazon and request an access token of sorts - only for the particular folder that belongs to the user I'm making the request for. Can anyone help me out and/or guide me to some sources where a similar problem was addressed? Don't think I'm the first one and the amazon documentation is so extensive that I don't really know where to start looking. Thanks a lot!

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  • Series On Embedded Development (Part 1)

    - by user12612705
    This is the first in a series of entries on developing applications for the embedded environment. Most of this information is relevant to any type of embedded development (and even for desktop and server too), not just Java. This information is based on a talk Hinkmond Wong and I gave at JavaOne 2012 entitled Reducing Dynamic Memory in Java Embedded Applications. One thing to remember when developing embeddded applications is that memory matters. Yes, memory matters in desktop and server environments as well, but there's just plain less of it in embedded devices. So I'm going to be talking about saving this precious resource as well as another precious resource, CPU cycles...and a bit about power too. CPU matters too, and again, in embedded devices, there's just plain less of it. What you'll find, no surprise, is that there's a trade-off between performance and memory. To get better performance, you need to use more memory, and to save more memory, you need to need to use more CPU cycles. I'll be discussing three Memory Reduction Categories: - Optionality, both build-time and runtime. Optionality is about providing options so you can get rid of the stuff you don't need and include the stuff you do need. - Tunability, which is about providing options so you can tune your application by trading performance for size, and vice-versa. - Efficiency, which is about balancing size savings with performance.

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  • How do you coordinate with co-workers to give a balanced interview?

    - by goldierox
    My company has been conducting a lot of interviews lately for candidates with various experience levels, ranging from interns to senior candidates. We put our candidates through five 45 minute interview sessions where we try to ask a range of questions. One person always asks the same questions that test logic and communication. The rest typically split time between a whiteboard coding question and a discussion of previous projects, technologies the interviewee has worked with, and what he/she is looking for a job. Generally, we know the range of questions that other people on the loop will ask. Sometimes we switch things up and end up having redundancies. Today, 3 interviewers asked tree-related questions. Other times, we've all honed in on the same project on a resume and have had the interviewee talk about it with everyone. I think a smooth interview process would help us learn more about the candidate while giving the impression to the candidate that we have our act together as a team. How do you coordinate with others in the interview loop to give a balanced interview?

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  • GlassFish/Java EE Community Open Forum Tomorrow!

    - by reza_rahman
    Still have lingering questions on the goals and future of GlassFish? Want to know a little more about the upcoming GlassFish 4.0.1 release? Something on your mind about Java EE 8/GlassFish 5? You have a golden opportunity to pose your questions and speak your mind tomorrow! The good folks over at C2B2 have gone through a lot of time and effort to organize a very useful online event for the London GlassFish User Group - they are having me answer all your questions online, in real time, "face-to-face". Steve Millidge of C2B2 will be moderating the questions and joining the conversation. Did I mention the event was online, free and open to anyone? The event is tomorrow (May 30th), so make sure to register as soon as possible through the C2B2 website (the registration page has more details on the event). It will be held at 4:30 PM BST / 11:30 AM EST / 8:30 AM PST - you must register to participate. Hope to talk to you tomorrow?

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  • Can't get my graphics driver (GMA 3150) to work

    - by bracus
    I've been searching like crazy trying to find a fix for this, it's the only thing that's not completely working on my setup. I see posts where people say it should be working but it just isn't. I have a Gateway LT2802u netbook and I installed 11.10 on this 2 days ago. Everything works except for accelerated graphics. At first I couldn't watch a simple flash video at all, but somehow I got it to work. Now the last problem I have is I can't watch HD videos, my screen resolution won't go higher than 1024x600, and my under my graphics driver it says "Unknown". After doing as much research as possible, I've come to the conclusion that it's the GMA 3150 graphics driver. There is a bunch of talk on it all over the interwebs but nothing lately. I've tried the fixes that some people have used but most when I try to get the package it's no longer there or available if that makes sense. I'm loving everything Ubuntu has to offer but it'll really bite if I can't use it any more because of this problem. Does anybody have any ideas? You'd really be helping a lot.

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  • Postfix on Snow Leopard unable to send MIME emails, including header contents in message body

    - by devvy
    I configured postfix on snow leopard by adding the following line to /etc/hostconfig: MAILSERVER=-YES- I then configured postfix to relay through my ISP's SMTP server. I added the following two lines in their respective places within /etc/postfix/main.cf: myhostname = 1and1.com relayhost = shawmail.vc.shawcable.net I then have a simple PHP mail function wrapper as follows: send_email("[email protected]", "[email protected]", "Test Email", "<p>This is a simple HTML email</p>"); echo "Done"; function send_email($from,$to,$subject,$message){ $header="From: <".$from."> "; $header.= 'MIME-Version: 1.0' . " "; $header.= 'Content-type: text/html; charset=iso-8859-1' . " "; $send_mail=mail($to,$subject,$message,$header); if(!$send_mail){ echo "ERROR"; } } With this, I am receiving an e-mail that appears to be improperly formatted. The message header is showing up in the body of the e-mail. The raw message content is as follows: Return-Path: <[email protected]> Delivery-Date: Tue, 27 Apr 2010 18:12:48 -0400 Received: from idcmail-mo2no.shaw.ca (idcmail-mo2no.shaw.ca [64.59.134.9]) by mx.perfora.net (node=mxus2) with ESMTP (Nemesis) id 0M4XlU-1NCtC81GVY-00z5UN for [email protected]; Tue, 27 Apr 2010 18:12:48 -0400 Message-Id: <[email protected]> Received: from pd6ml3no-ssvc.prod.shaw.ca ([10.0.153.149]) by pd6mo1no-svcs.prod.shaw.ca with ESMTP; 27 Apr 2010 16:12:47 -0600 X-Cloudmark-SP-Filtered: true X-Cloudmark-SP-Result: v=1.0 c=1 a=VphdPIyG4kEA:10 a=hATtCjKilyj9ZF5m5A62ag==:17 a=mC_jT1gcAAAA:8 a=QLyc3QejAAAA:8 a=DGW4GvdtALggLTu6w9AA:9 a=KbDtEDGyCi7QHcNhDYYwsF92SU8A:4 a=uch7kV7NfGgA:10 a=5ZEL1eDBWGAA:10 Received: from unknown (HELO 1and1.com) ([24.84.196.104]) by pd6ml3no-dmz.prod.shaw.ca with ESMTP; 27 Apr 2010 16:12:48 -0600 Received: by 1and1.com (Postfix, from userid 70) id BB08D14ECFC; Tue, 27 Apr 2010 15:12:47 -0700 (PDT) To: [email protected] Subject: Test Email X-PHP-Originating-Script: 501:test.php Date: Tue, 27 Apr 2010 18:12:48 -0400 X-UI-Junk: AutoMaybeJunk +30 (SPA); V01:LYI2BGRt:7TwGx5jxe8cylj5nOTae9JQXYqoWvG2w4ZSfwYCXmHCH/5vVNCE fRD7wNNM86txwLDTO522ZNxyNHhvJUK9d2buMQuAUCMoea2jJHaDdtRgkGxNSkO2 v6svm0LsZikLMqRErHtBCYEWIgxp2bl0W3oA3nIbtfp3li0kta27g/ZjoXcgz5Sw B8lEqWBqKWMSta1mCM+XD/RbWVsjr+LqTKg== Envelope-To: [email protected] From: <[email protected]> MIME-Version: 1.0 Content-type: text/html; charset=iso-8859-1 Message-Id: <[email protected]> Date: Tue, 27 Apr 2010 15:12:47 -0700 (PDT) <p>This is a simple HTML email</p> And here are the contents of my /var/log/mail.log file after sending the email: Apr 27 15:29:01 User-iMac postfix/qmgr[705]: 74B1514EDDF: removed Apr 27 15:29:30 User-iMac postfix/pickup[704]: 25FBC14EDF0: uid=70 from=<_www> Apr 27 15:29:30 User-iMac postfix/master[758]: fatal: open lock file pid/master.pid: unable to set exclusive lock: Resource temporarily unavailable Apr 27 15:29:30 User-iMac postfix/cleanup[745]: 25FBC14EDF0: message-id=<[email protected]> Apr 27 15:29:30 User-iMac postfix/qmgr[705]: 25FBC14EDF0: from=<[email protected]>, size=423, nrcpt=1 (queue active) Apr 27 15:29:30 User-iMac postfix/smtp[747]: 25FBC14EDF0: to=<[email protected]>, relay=shawmail.vc.shawcable.net[64.59.128.135]:25, delay=0.21, delays=0.01/0/0.1/0.1, dsn=2.0.0, status=sent (250 ok: Message 25784419 accepted) Apr 27 15:29:30 User-iMac postfix/qmgr[705]: 25FBC14EDF0: removed Two other people in the office have followed the exact same process and are running the exact same script, version of snow leopard, php, etc. and everything is working fine for them. I've even copied their config files to my machine, restarted postfix, restarted apache, all to no avail. Does anyone know what steps I could take to resolve the issue? This is boggling my mind... Thanks

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  • Product Review: qlWebDS Pro

    There are many products available for creating directory style web sites, but web masters prefer simple ones that contain features relevant to them. In this review, Anand puts the Pro version of qlWebDS software to the test. He examines the various features and provides suggestions for improving the quality of the product.

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  • Finding a Relative Path in .NET

    - by Rick Strahl
    Here’s a nice and simple path utility that I’ve needed in a number of applications: I need to find a relative path based on a base path. So if I’m working in a folder called c:\temp\templates\ and I want to find a relative path for c:\temp\templates\subdir\test.txt I want to receive back subdir\test.txt. Or if I pass c:\ I want to get back ..\..\ – in other words always return a non-hardcoded path based on some other known directory. I’ve had a routine in my library that does this via some lengthy string parsing routines, but ran into some Uri processing today that made me realize that this code could be greatly simplified by using the System.Uri class instead. Here’s the simple static method: /// <summary> /// Returns a relative path string from a full path based on a base path /// provided. /// </summary> /// <param name="fullPath">The path to convert. Can be either a file or a directory</param> /// <param name="basePath">The base path on which relative processing is based. Should be a directory.</param> /// <returns> /// String of the relative path. /// /// Examples of returned values: /// test.txt, ..\test.txt, ..\..\..\test.txt, ., .., subdir\test.txt /// </returns> public static string GetRelativePath(string fullPath, string basePath ) { // ForceBasePath to a path if (!basePath.EndsWith("\\")) basePath += "\\"; Uri baseUri = new Uri(basePath); Uri fullUri = new Uri(fullPath); Uri relativeUri = baseUri.MakeRelativeUri(fullUri); // Uri's use forward slashes so convert back to backward slashes return relativeUri.ToString().Replace("/", "\\"); } You can then call it like this: string relPath = FileUtils.GetRelativePath("c:\temp\templates","c:\temp\templates\subdir\test.txt") It’s not exactly rocket science but it’s useful in many scenarios where you’re working with files based on an application base directory. Right now I’m working on a templating solution (using the Razor Engine) where templates live in a base directory and are supplied as relative paths to that base directory. Resolving these relative paths both ways is important in order to properly check for existance of files and their change status in this case. Not the kind of thing you use every day, but useful to remember.© Rick Strahl, West Wind Technologies, 2005-2010Posted in .NET  CSharp  

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  • Multi-tenant ASP.NET MVC – Introduction

    - by zowens
    I’ve read a few different blogs that talk about multi-tenancy and how to resolve some of the issues surrounding multi-tenancy. What I’ve come to realize is that these implementations overcomplicate the issues and give only a muddy implementation! I’ve seen some really illogical code out there. I have recently been building a multi-tenancy framework for internal use at eagleenvision.net. Through this process, I’ve realized a few different techniques to make building multi-tenant applications actually quite easy. I will be posting a few different entries over the issue and my personal implementation. In this first post, I will discuss what multi-tenancy means and how my implementation will be structured.   So what’s the problem? Here’s the deal. Multi-tenancy is basically a technique of code-reuse of web application code. A multi-tenant application is an application that runs a single instance for multiple clients. Here the “client” is different URL bindings on IIS using ASP.NET MVC. The problem with different instances of the, essentially, same application is that you have to spin up different instances of ASP.NET. As the number of running instances of ASP.NET grows, so does the memory footprint of IIS. Stack Exchange shifted its architecture to multi-tenancy March. As the blog post explains, multi-tenancy saves cost in terms of memory utilization and physical disc storage. If you use the same code base for many applications, multi-tenancy just makes sense. You’ll reduce the amount of work it takes to synchronize the site implementations and you’ll thank your lucky stars later for choosing to use one application for multiple sites. Multi-tenancy allows the freedom of extensibility while relying on some pre-built code.   You’d think this would be simple. I have actually seen a real lack of reference material on the subject in terms of ASP.NET MVC. This is somewhat surprising given the number of users of ASP.NET MVC. However, I will certainly fill the void ;). Implementing a multi-tenant application takes a little thinking. It’s not straight-forward because the possibilities of implementation are endless. I have yet to see a great implementation of a multi-tenant MVC application. The only one that comes close to what I have in mind is Rob Ashton’s implementation (all the entries are listed on this page). There’s some really nasty code in there… something I’d really like to avoid. He has also written a library (MvcEx) that attempts to aid multi-tenant development. This code is even worse, in my honest opinion. Once I start seeing Reflection.Emit, I have to assume the worst :) In all seriousness, if his implementation makes sense to you, use it! It’s a fine implementation that should be given a look. At least look at the code. I will reference MvcEx going forward as a comparison to my implementation. I will explain why my approach differs from MvcEx and how it is better or worse (hopefully better).   Core Goals of my Multi-Tenant Implementation The first, and foremost, goal is to use Inversion of Control containers to my advantage. As you will see throughout this series, I pass around containers quite frequently and rely on their use heavily. I will be using StructureMap in my implementation. However, you could probably use your favorite IoC tool instead. <RANT> However, please don’t be stupid and abstract your IoC tool. Each IoC is powerful and by abstracting the capabilities, you’re doing yourself a real disservice. Who in the world swaps out IoC tools…? No one!</RANT> (It had to be said.) I will outline some of the goodness of StructureMap as we go along. This is really an invaluable tool in my tool belt and simple to use in my multi-tenant implementation. The second core goal is to represent a tenant as easily as possible. Just as a dependency container will be a first-class citizen, so will a tenant. This allows us to easily extend and use tenants. This will also allow different ways of “plugging in” tenants into your application. In my implementation, there will be a single dependency container for a single tenant. This will enable isolation of the dependencies of the tenant. The third goal is to use composition as a means to delegate “core” functions out to the tenant. More on this later.   Features In MvcExt, “Modules” are a code element of the infrastructure. I have simplified this concept and have named this “Features”. A feature is a simple element of an application. Controllers can be specified to have a feature and actions can have “sub features”. Each tenant can select features it needs and the other features will be hidden to the tenant’s users. My implementation doesn’t require something to be a feature. A controller can be common to all tenants. For example, (as you will see) I have a “Content” controller that will return the CSS, Javascript and Images for a tenant. This is common logic to all tenants and shouldn’t be hidden or considered a “feature”; Content is a core component.   Up next My next post will be all about the code. I will reveal some of the foundation to the way I do multi-tenancy. I will have posts dedicated to Foundation, Controllers, Views, Caching, Content and how to setup the tenants. Each post will be in-depth about the issues and implementation details, while adhering to my core goals outlined in this post. As always, comment with questions of DM me on twitter or send me an email.

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  • SimpleMembership, Membership Providers, Universal Providers and the new ASP.NET 4.5 Web Forms and ASP.NET MVC 4 templates

    - by Jon Galloway
    The ASP.NET MVC 4 Internet template adds some new, very useful features which are built on top of SimpleMembership. These changes add some great features, like a much simpler and extensible membership API and support for OAuth. However, the new account management features require SimpleMembership and won't work against existing ASP.NET Membership Providers. I'll start with a summary of top things you need to know, then dig into a lot more detail. Summary: SimpleMembership has been designed as a replacement for traditional the previous ASP.NET Role and Membership provider system SimpleMembership solves common problems people ran into with the Membership provider system and was designed for modern user / membership / storage needs SimpleMembership integrates with the previous membership system, but you can't use a MembershipProvider with SimpleMembership The new ASP.NET MVC 4 Internet application template AccountController requires SimpleMembership and is not compatible with previous MembershipProviders You can continue to use existing ASP.NET Role and Membership providers in ASP.NET 4.5 and ASP.NET MVC 4 - just not with the ASP.NET MVC 4 AccountController The existing ASP.NET Role and Membership provider system remains supported as is part of the ASP.NET core ASP.NET 4.5 Web Forms does not use SimpleMembership; it implements OAuth on top of ASP.NET Membership The ASP.NET Web Site Administration Tool (WSAT) is not compatible with SimpleMembership The following is the result of a few conversations with Erik Porter (PM for ASP.NET MVC) to make sure I had some the overall details straight, combined with a lot of time digging around in ILSpy and Visual Studio's assembly browsing tools. SimpleMembership: The future of membership for ASP.NET The ASP.NET Membership system was introduces with ASP.NET 2.0 back in 2005. It was designed to solve common site membership requirements at the time, which generally involved username / password based registration and profile storage in SQL Server. It was designed with a few extensibility mechanisms - notably a provider system (which allowed you override some specifics like backing storage) and the ability to store additional profile information (although the additional  profile information was packed into a single column which usually required access through the API). While it's sometimes frustrating to work with, it's held up for seven years - probably since it handles the main use case (username / password based membership in a SQL Server database) smoothly and can be adapted to most other needs (again, often frustrating, but it can work). The ASP.NET Web Pages and WebMatrix efforts allowed the team an opportunity to take a new look at a lot of things - e.g. the Razor syntax started with ASP.NET Web Pages, not ASP.NET MVC. The ASP.NET Web Pages team designed SimpleMembership to (wait for it) simplify the task of dealing with membership. As Matthew Osborn said in his post Using SimpleMembership With ASP.NET WebPages: With the introduction of ASP.NET WebPages and the WebMatrix stack our team has really be focusing on making things simpler for the developer. Based on a lot of customer feedback one of the areas that we wanted to improve was the built in security in ASP.NET. So with this release we took that time to create a new built in (and default for ASP.NET WebPages) security provider. I say provider because the new stuff is still built on the existing ASP.NET framework. So what do we call this new hotness that we have created? Well, none other than SimpleMembership. SimpleMembership is an umbrella term for both SimpleMembership and SimpleRoles. Part of simplifying membership involved fixing some common problems with ASP.NET Membership. Problems with ASP.NET Membership ASP.NET Membership was very obviously designed around a set of assumptions: Users and user information would most likely be stored in a full SQL Server database or in Active Directory User and profile information would be optimized around a set of common attributes (UserName, Password, IsApproved, CreationDate, Comment, Role membership...) and other user profile information would be accessed through a profile provider Some problems fall out of these assumptions. Requires Full SQL Server for default cases The default, and most fully featured providers ASP.NET Membership providers (SQL Membership Provider, SQL Role Provider, SQL Profile Provider) require full SQL Server. They depend on stored procedure support, and they rely on SQL Server cache dependencies, they depend on agents for clean up and maintenance. So the main SQL Server based providers don't work well on SQL Server CE, won't work out of the box on SQL Azure, etc. Note: Cory Fowler recently let me know about these Updated ASP.net scripts for use with Microsoft SQL Azure which do support membership, personalization, profile, and roles. But the fact that we need a support page with a set of separate SQL scripts underscores the underlying problem. Aha, you say! Jon's forgetting the Universal Providers, a.k.a. System.Web.Providers! Hold on a bit, we'll get to those... Custom Membership Providers have to work with a SQL-Server-centric API If you want to work with another database or other membership storage system, you need to to inherit from the provider base classes and override a bunch of methods which are tightly focused on storing a MembershipUser in a relational database. It can be done (and you can often find pretty good ones that have already been written), but it's a good amount of work and often leaves you with ugly code that has a bunch of System.NotImplementedException fun since there are a lot of methods that just don't apply. Designed around a specific view of users, roles and profiles The existing providers are focused on traditional membership - a user has a username and a password, some specific roles on the site (e.g. administrator, premium user), and may have some additional "nice to have" optional information that can be accessed via an API in your application. This doesn't fit well with some modern usage patterns: In OAuth and OpenID, the user doesn't have a password Often these kinds of scenarios map better to user claims or rights instead of monolithic user roles For many sites, profile or other non-traditional information is very important and needs to come from somewhere other than an API call that maps to a database blob What would work a lot better here is a system in which you were able to define your users, rights, and other attributes however you wanted and the membership system worked with your model - not the other way around. Requires specific schema, overflow in blob columns I've already mentioned this a few times, but it bears calling out separately - ASP.NET Membership focuses on SQL Server storage, and that storage is based on a very specific database schema. SimpleMembership as a better membership system As you might have guessed, SimpleMembership was designed to address the above problems. Works with your Schema As Matthew Osborn explains in his Using SimpleMembership With ASP.NET WebPages post, SimpleMembership is designed to integrate with your database schema: All SimpleMembership requires is that there are two columns on your users table so that we can hook up to it – an “ID” column and a “username” column. The important part here is that they can be named whatever you want. For instance username doesn't have to be an alias it could be an email column you just have to tell SimpleMembership to treat that as the “username” used to log in. Matthew's example shows using a very simple user table named Users (it could be named anything) with a UserID and Username column, then a bunch of other columns he wanted in his app. Then we point SimpleMemberhip at that table with a one-liner: WebSecurity.InitializeDatabaseFile("SecurityDemo.sdf", "Users", "UserID", "Username", true); No other tables are needed, the table can be named anything we want, and can have pretty much any schema we want as long as we've got an ID and something that we can map to a username. Broaden database support to the whole SQL Server family While SimpleMembership is not database agnostic, it works across the SQL Server family. It continues to support full SQL Server, but it also works with SQL Azure, SQL Server CE, SQL Server Express, and LocalDB. Everything's implemented as SQL calls rather than requiring stored procedures, views, agents, and change notifications. Note that SimpleMembership still requires some flavor of SQL Server - it won't work with MySQL, NoSQL databases, etc. You can take a look at the code in WebMatrix.WebData.dll using a tool like ILSpy if you'd like to see why - there places where SQL Server specific SQL statements are being executed, especially when creating and initializing tables. It seems like you might be able to work with another database if you created the tables separately, but I haven't tried it and it's not supported at this point. Note: I'm thinking it would be possible for SimpleMembership (or something compatible) to run Entity Framework so it would work with any database EF supports. That seems useful to me - thoughts? Note: SimpleMembership has the same database support - anything in the SQL Server family - that Universal Providers brings to the ASP.NET Membership system. Easy to with Entity Framework Code First The problem with with ASP.NET Membership's system for storing additional account information is that it's the gate keeper. That means you're stuck with its schema and accessing profile information through its API. SimpleMembership flips that around by allowing you to use any table as a user store. That means you're in control of the user profile information, and you can access it however you'd like - it's just data. Let's look at a practical based on the AccountModel.cs class in an ASP.NET MVC 4 Internet project. Here I'm adding a Birthday property to the UserProfile class. [Table("UserProfile")] public class UserProfile { [Key] [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] public int UserId { get; set; } public string UserName { get; set; } public DateTime Birthday { get; set; } } Now if I want to access that information, I can just grab the account by username and read the value. var context = new UsersContext(); var username = User.Identity.Name; var user = context.UserProfiles.SingleOrDefault(u => u.UserName == username); var birthday = user.Birthday; So instead of thinking of SimpleMembership as a big membership API, think of it as something that handles membership based on your user database. In SimpleMembership, everything's keyed off a user row in a table you define rather than a bunch of entries in membership tables that were out of your control. How SimpleMembership integrates with ASP.NET Membership Okay, enough sales pitch (and hopefully background) on why things have changed. How does this affect you? Let's start with a diagram to show the relationship (note: I've simplified by removing a few classes to show the important relationships): So SimpleMembershipProvider is an implementaiton of an ExtendedMembershipProvider, which inherits from MembershipProvider and adds some other account / OAuth related things. Here's what ExtendedMembershipProvider adds to MembershipProvider: The important thing to take away here is that a SimpleMembershipProvider is a MembershipProvider, but a MembershipProvider is not a SimpleMembershipProvider. This distinction is important in practice: you cannot use an existing MembershipProvider (including the Universal Providers found in System.Web.Providers) with an API that requires a SimpleMembershipProvider, including any of the calls in WebMatrix.WebData.WebSecurity or Microsoft.Web.WebPages.OAuth.OAuthWebSecurity. However, that's as far as it goes. Membership Providers still work if you're accessing them through the standard Membership API, and all of the core stuff  - including the AuthorizeAttribute, role enforcement, etc. - will work just fine and without any change. Let's look at how that affects you in terms of the new templates. Membership in the ASP.NET MVC 4 project templates ASP.NET MVC 4 offers six Project Templates: Empty - Really empty, just the assemblies, folder structure and a tiny bit of basic configuration. Basic - Like Empty, but with a bit of UI preconfigured (css / images / bundling). Internet - This has both a Home and Account controller and associated views. The Account Controller supports registration and login via either local accounts and via OAuth / OpenID providers. Intranet - Like the Internet template, but it's preconfigured for Windows Authentication. Mobile - This is preconfigured using jQuery Mobile and is intended for mobile-only sites. Web API - This is preconfigured for a service backend built on ASP.NET Web API. Out of these templates, only one (the Internet template) uses SimpleMembership. ASP.NET MVC 4 Basic template The Basic template has configuration in place to use ASP.NET Membership with the Universal Providers. You can see that configuration in the ASP.NET MVC 4 Basic template's web.config: <profile defaultProvider="DefaultProfileProvider"> <providers> <add name="DefaultProfileProvider" type="System.Web.Providers.DefaultProfileProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" /> </providers> </profile> <membership defaultProvider="DefaultMembershipProvider"> <providers> <add name="DefaultMembershipProvider" type="System.Web.Providers.DefaultMembershipProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/" /> </providers> </membership> <roleManager defaultProvider="DefaultRoleProvider"> <providers> <add name="DefaultRoleProvider" type="System.Web.Providers.DefaultRoleProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" /> </providers> </roleManager> <sessionState mode="InProc" customProvider="DefaultSessionProvider"> <providers> <add name="DefaultSessionProvider" type="System.Web.Providers.DefaultSessionStateProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" /> </providers> </sessionState> This means that it's business as usual for the Basic template as far as ASP.NET Membership works. ASP.NET MVC 4 Internet template The Internet template has a few things set up to bootstrap SimpleMembership: \Models\AccountModels.cs defines a basic user account and includes data annotations to define keys and such \Filters\InitializeSimpleMembershipAttribute.cs creates the membership database using the above model, then calls WebSecurity.InitializeDatabaseConnection which verifies that the underlying tables are in place and marks initialization as complete (for the application's lifetime) \Controllers\AccountController.cs makes heavy use of OAuthWebSecurity (for OAuth account registration / login / management) and WebSecurity. WebSecurity provides account management services for ASP.NET MVC (and Web Pages) WebSecurity can work with any ExtendedMembershipProvider. There's one in the box (SimpleMembershipProvider) but you can write your own. Since a standard MembershipProvider is not an ExtendedMembershipProvider, WebSecurity will throw exceptions if the default membership provider is a MembershipProvider rather than an ExtendedMembershipProvider. Practical example: Create a new ASP.NET MVC 4 application using the Internet application template Install the Microsoft ASP.NET Universal Providers for LocalDB NuGet package Run the application, click on Register, add a username and password, and click submit You'll get the following execption in AccountController.cs::Register: To call this method, the "Membership.Provider" property must be an instance of "ExtendedMembershipProvider". This occurs because the ASP.NET Universal Providers packages include a web.config transform that will update your web.config to add the Universal Provider configuration I showed in the Basic template example above. When WebSecurity tries to use the configured ASP.NET Membership Provider, it checks if it can be cast to an ExtendedMembershipProvider before doing anything else. So, what do you do? Options: If you want to use the new AccountController, you'll either need to use the SimpleMembershipProvider or another valid ExtendedMembershipProvider. This is pretty straightforward. If you want to use an existing ASP.NET Membership Provider in ASP.NET MVC 4, you can't use the new AccountController. You can do a few things: Replace  the AccountController.cs and AccountModels.cs in an ASP.NET MVC 4 Internet project with one from an ASP.NET MVC 3 application (you of course won't have OAuth support). Then, if you want, you can go through and remove other things that were built around SimpleMembership - the OAuth partial view, the NuGet packages (e.g. the DotNetOpenAuthAuth package, etc.) Use an ASP.NET MVC 4 Internet application template and add in a Universal Providers NuGet package. Then copy in the AccountController and AccountModel classes. Create an ASP.NET MVC 3 project and upgrade it to ASP.NET MVC 4 using the steps shown in the ASP.NET MVC 4 release notes. None of these are particularly elegant or simple. Maybe we (or just me?) can do something to make this simpler - perhaps a NuGet package. However, this should be an edge case - hopefully the cases where you'd need to create a new ASP.NET but use legacy ASP.NET Membership Providers should be pretty rare. Please let me (or, preferably the team) know if that's an incorrect assumption. Membership in the ASP.NET 4.5 project template ASP.NET 4.5 Web Forms took a different approach which builds off ASP.NET Membership. Instead of using the WebMatrix security assemblies, Web Forms uses Microsoft.AspNet.Membership.OpenAuth assembly. I'm no expert on this, but from a bit of time in ILSpy and Visual Studio's (very pretty) dependency graphs, this uses a Membership Adapter to save OAuth data into an EF managed database while still running on top of ASP.NET Membership. Note: There may be a way to use this in ASP.NET MVC 4, although it would probably take some plumbing work to hook it up. How does this fit in with Universal Providers (System.Web.Providers)? Just to summarize: Universal Providers are intended for cases where you have an existing ASP.NET Membership Provider and you want to use it with another SQL Server database backend (other than SQL Server). It doesn't require agents to handle expired session cleanup and other background tasks, it piggybacks these tasks on other calls. Universal Providers are not really, strictly speaking, universal - at least to my way of thinking. They only work with databases in the SQL Server family. Universal Providers do not work with Simple Membership. The Universal Providers packages include some web config transforms which you would normally want when you're using them. What about the Web Site Administration Tool? Visual Studio includes tooling to launch the Web Site Administration Tool (WSAT) to configure users and roles in your application. WSAT is built to work with ASP.NET Membership, and is not compatible with Simple Membership. There are two main options there: Use the WebSecurity and OAuthWebSecurity API to manage the users and roles Create a web admin using the above APIs Since SimpleMembership runs on top of your database, you can update your users as you would any other data - via EF or even in direct database edits (in development, of course)

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  • Integration of WordPress With WordPress bbPress

    bbPress is a powerful and fully featured forum software that can be integrated with blogging tools like WordPress. A first glance at the software, gives the impression that it is simple and devoid of any complicated structure, but one has to use it in order, to believe that it is a very powerful tool.

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  • VS 2010 SP1 and SQL CE

    - by ScottGu
    Last month we released the Beta of VS 2010 Service Pack 1 (SP1).  You can learn more about the VS 2010 SP1 Beta from Jason Zander’s two blog posts about it, and from Scott Hanselman’s blog post that covers some of the new capabilities enabled with it.   You can download and install the VS 2010 SP1 Beta here. Last week I blogged about the new Visual Studio support for IIS Express that we are adding with VS 2010 SP1. In today’s post I’m going to talk about the new VS 2010 SP1 tooling support for SQL CE, and walkthrough some of the cool scenarios it enables.  SQL CE – What is it and why should you care? SQL CE is a free, embedded, database engine that enables easy database storage. No Database Installation Required SQL CE does not require you to run a setup or install a database server in order to use it.  You can simply copy the SQL CE binaries into the \bin directory of your ASP.NET application, and then your web application can use it as a database engine.  No setup or extra security permissions are required for it to run. You do not need to have an administrator account on the machine. Just copy your web application onto any server and it will work. This is true even of medium-trust applications running in a web hosting environment. SQL CE runs in-memory within your ASP.NET application and will start-up when you first access a SQL CE database, and will automatically shutdown when your application is unloaded.  SQL CE databases are stored as files that live within the \App_Data folder of your ASP.NET Applications. Works with Existing Data APIs SQL CE 4 works with existing .NET-based data APIs, and supports a SQL Server compatible query syntax.  This means you can use existing data APIs like ADO.NET, as well as use higher-level ORMs like Entity Framework and NHibernate with SQL CE.  This enables you to use the same data programming skills and data APIs you know today. Supports Development, Testing and Production Scenarios SQL CE can be used for development scenarios, testing scenarios, and light production usage scenarios.  With the SQL CE 4 release we’ve done the engineering work to ensure that SQL CE won’t crash or deadlock when used in a multi-threaded server scenario (like ASP.NET).  This is a big change from previous releases of SQL CE – which were designed for client-only scenarios and which explicitly blocked running in web-server environments.  Starting with SQL CE 4 you can use it in a web-server as well. There are no license restrictions with SQL CE.  It is also totally free. Easy Migration to SQL Server SQL CE is an embedded database – which makes it ideal for development, testing, and light-usage scenarios.  For high-volume sites and applications you’ll probably want to migrate your database to use SQL Server Express (which is free), SQL Server or SQL Azure.  These servers enable much better scalability, more development features (including features like Stored Procedures – which aren’t supported with SQL CE), as well as more advanced data management capabilities. We’ll ship migration tools that enable you to optionally take SQL CE databases and easily upgrade them to use SQL Server Express, SQL Server, or SQL Azure.  You will not need to change your code when upgrading a SQL CE database to SQL Server or SQL Azure.  Our goal is to enable you to be able to simply change the database connection string in your web.config file and have your application just work. New Tooling Support for SQL CE in VS 2010 SP1 VS 2010 SP1 includes much improved tooling support for SQL CE, and adds support for using SQL CE within ASP.NET projects for the first time.  With VS 2010 SP1 you can now: Create new SQL CE Databases Edit and Modify SQL CE Database Schema and Indexes Populate SQL CE Databases within Data Use the Entity Framework (EF) designer to create model layers against SQL CE databases Use EF Code First to define model layers in code, then create a SQL CE database from them, and optionally edit the DB with VS Deploy SQL CE databases to remote servers using Web Deploy and optionally convert them to full SQL Server databases You can take advantage of all of the above features from within both ASP.NET Web Forms and ASP.NET MVC based projects. Download You can enable SQL CE tooling support within VS 2010 by first installing VS 2010 SP1 (beta). Once SP1 is installed, you’ll also then need to install the SQL CE Tools for Visual Studio download.  This is a separate download that enables the SQL CE tooling support for VS 2010 SP1. Walkthrough of Two Scenarios In this blog post I’m going to walkthrough how you can take advantage of SQL CE and VS 2010 SP1 using both an ASP.NET Web Forms and an ASP.NET MVC based application. Specifically, we’ll walkthrough: How to create a SQL CE database using VS 2010 SP1, then use the EF4 visual designers in Visual Studio to construct a model layer from it, and then display and edit the data using an ASP.NET GridView control. How to use an EF Code First approach to define a model layer using POCO classes and then have EF Code-First “auto-create” a SQL CE database for us based on our model classes.  We’ll then look at how we can use the new VS 2010 SP1 support for SQL CE to inspect the database that was created, populate it with data, and later make schema changes to it.  We’ll do all this within the context of an ASP.NET MVC based application. You can follow the two walkthroughs below on your own machine by installing VS 2010 SP1 (beta) and then installing the SQL CE Tools for Visual Studio download (which is a separate download that enables SQL CE tooling support for VS 2010 SP1). Walkthrough 1: Create a SQL CE Database, Create EF Model Classes, Edit the Data with a GridView This first walkthrough will demonstrate how to create and define a SQL CE database within an ASP.NET Web Form application.  We’ll then build an EF model layer for it and use that model layer to enable data editing scenarios with an <asp:GridView> control. Step 1: Create a new ASP.NET Web Forms Project We’ll begin by using the File->New Project menu command within Visual Studio to create a new ASP.NET Web Forms project.  We’ll use the “ASP.NET Web Application” project template option so that it has a default UI skin implemented: Step 2: Create a SQL CE Database Right click on the “App_Data” folder within the created project and choose the “Add->New Item” menu command: This will bring up the “Add Item” dialog box.  Select the “SQL Server Compact 4.0 Local Database” item (new in VS 2010 SP1) and name the database file to create “Store.sdf”: Note that SQL CE database files have a .sdf filename extension. Place them within the /App_Data folder of your ASP.NET application to enable easy deployment. When we clicked the “Add” button above a Store.sdf file was added to our project: Step 3: Adding a “Products” Table Double-clicking the “Store.sdf” database file will open it up within the Server Explorer tab.  Since it is a new database there are no tables within it: Right click on the “Tables” icon and choose the “Create Table” menu command to create a new database table.  We’ll name the new table “Products” and add 4 columns to it.  We’ll mark the first column as a primary key (and make it an identify column so that its value will automatically increment with each new row): When we click “ok” our new Products table will be created in the SQL CE database. Step 4: Populate with Data Once our Products table is created it will show up within the Server Explorer.  We can right-click it and choose the “Show Table Data” menu command to edit its data: Let’s add a few sample rows of data to it: Step 5: Create an EF Model Layer We have a SQL CE database with some data in it – let’s now create an EF Model Layer that will provide a way for us to easily query and update data within it. Let’s right-click on our project and choose the “Add->New Item” menu command.  This will bring up the “Add New Item” dialog – select the “ADO.NET Entity Data Model” item within it and name it “Store.edmx” This will add a new Store.edmx item to our solution explorer and launch a wizard that allows us to quickly create an EF model: Select the “Generate From Database” option above and click next.  Choose to use the Store.sdf SQL CE database we just created and then click next again.  The wizard will then ask you what database objects you want to import into your model.  Let’s choose to import the “Products” table we created earlier: When we click the “Finish” button Visual Studio will open up the EF designer.  It will have a Product entity already on it that maps to the “Products” table within our SQL CE database: The VS 2010 SP1 EF designer works exactly the same with SQL CE as it does already with SQL Server and SQL Express.  The Product entity above will be persisted as a class (called “Product”) that we can programmatically work against within our ASP.NET application. Step 6: Compile the Project Before using your model layer you’ll need to build your project.  Do a Ctrl+Shift+B to compile the project, or use the Build->Build Solution menu command. Step 7: Create a Page that Uses our EF Model Layer Let’s now create a simple ASP.NET Web Form that contains a GridView control that we can use to display and edit the our Products data (via the EF Model Layer we just created). Right-click on the project and choose the Add->New Item command.  Select the “Web Form from Master Page” item template, and name the page you create “Products.aspx”.  Base the master page on the “Site.Master” template that is in the root of the project. Add an <h2>Products</h2> heading the new Page, and add an <asp:gridview> control within it: Then click the “Design” tab to switch into design-view. Select the GridView control, and then click the top-right corner to display the GridView’s “Smart Tasks” UI: Choose the “New data source…” drop down option above.  This will bring up the below dialog which allows you to pick your Data Source type: Select the “Entity” data source option – which will allow us to easily connect our GridView to the EF model layer we created earlier.  This will bring up another dialog that allows us to pick our model layer: Select the “StoreEntities” option in the dropdown – which is the EF model layer we created earlier.  Then click next – which will allow us to pick which entity within it we want to bind to: Select the “Products” entity in the above dialog – which indicates that we want to bind against the “Product” entity class we defined earlier.  Then click the “Enable automatic updates” checkbox to ensure that we can both query and update Products.  When you click “Finish” VS will wire-up an <asp:EntityDataSource> to your <asp:GridView> control: The last two steps we’ll do will be to click the “Enable Editing” checkbox on the Grid (which will cause the Grid to display an “Edit” link on each row) and (optionally) use the Auto Format dialog to pick a UI template for the Grid. Step 8: Run the Application Let’s now run our application and browse to the /Products.aspx page that contains our GridView.  When we do so we’ll see a Grid UI of the Products within our SQL CE database. Clicking the “Edit” link for any of the rows will allow us to edit their values: When we click “Update” the GridView will post back the values, persist them through our EF Model Layer, and ultimately save them within our SQL CE database. Learn More about using EF with ASP.NET Web Forms Read this tutorial series on the http://asp.net site to learn more about how to use EF with ASP.NET Web Forms.  The tutorial series uses SQL Express as the database – but the nice thing is that all of the same steps/concepts can also now also be done with SQL CE.   Walkthrough 2: Using EF Code-First with SQL CE and ASP.NET MVC 3 We used a database-first approach with the sample above – where we first created the database, and then used the EF designer to create model classes from the database.  In addition to supporting a designer-based development workflow, EF also enables a more code-centric option which we call “code first development”.  Code-First Development enables a pretty sweet development workflow.  It enables you to: Define your model objects by simply writing “plain old classes” with no base classes or visual designer required Use a “convention over configuration” approach that enables database persistence without explicitly configuring anything Optionally override the convention-based persistence and use a fluent code API to fully customize the persistence mapping Optionally auto-create a database based on the model classes you define – allowing you to start from code first I’ve done several blog posts about EF Code First in the past – I really think it is great.  The good news is that it also works very well with SQL CE. The combination of SQL CE, EF Code First, and the new VS tooling support for SQL CE, enables a pretty nice workflow.  Below is a simple example of how you can use them to build a simple ASP.NET MVC 3 application. Step 1: Create a new ASP.NET MVC 3 Project We’ll begin by using the File->New Project menu command within Visual Studio to create a new ASP.NET MVC 3 project.  We’ll use the “Internet Project” template so that it has a default UI skin implemented: Step 2: Use NuGet to Install EFCodeFirst Next we’ll use the NuGet package manager (automatically installed by ASP.NET MVC 3) to add the EFCodeFirst library to our project.  We’ll use the Package Manager command shell to do this.  Bring up the package manager console within Visual Studio by selecting the View->Other Windows->Package Manager Console menu command.  Then type: install-package EFCodeFirst within the package manager console to download the EFCodeFirst library and have it be added to our project: When we enter the above command, the EFCodeFirst library will be downloaded and added to our application: Step 3: Build Some Model Classes Using a “code first” based development workflow, we will create our model classes first (even before we have a database).  We create these model classes by writing code. For this sample, we will right click on the “Models” folder of our project and add the below three classes to our project: The “Dinner” and “RSVP” model classes above are “plain old CLR objects” (aka POCO).  They do not need to derive from any base classes or implement any interfaces, and the properties they expose are standard .NET data-types.  No data persistence attributes or data code has been added to them.   The “NerdDinners” class derives from the DbContext class (which is supplied by EFCodeFirst) and handles the retrieval/persistence of our Dinner and RSVP instances from a database. Step 4: Listing Dinners We’ve written all of the code necessary to implement our model layer for this simple project.  Let’s now expose and implement the URL: /Dinners/Upcoming within our project.  We’ll use it to list upcoming dinners that happen in the future. We’ll do this by right-clicking on our “Controllers” folder and select the “Add->Controller” menu command.  We’ll name the Controller we want to create “DinnersController”.  We’ll then implement an “Upcoming” action method within it that lists upcoming dinners using our model layer above.  We will use a LINQ query to retrieve the data and pass it to a View to render with the code below: We’ll then right-click within our Upcoming method and choose the “Add-View” menu command to create an “Upcoming” view template that displays our dinners.  We’ll use the “empty” template option within the “Add View” dialog and write the below view template using Razor: Step 4: Configure our Project to use a SQL CE Database We have finished writing all of our code – our last step will be to configure a database connection-string to use. We will point our NerdDinners model class to a SQL CE database by adding the below <connectionString> to the web.config file at the top of our project: EF Code First uses a default convention where context classes will look for a connection-string that matches the DbContext class name.  Because we created a “NerdDinners” class earlier, we’ve also named our connectionstring “NerdDinners”.  Above we are configuring our connection-string to use SQL CE as the database, and telling it that our SQL CE database file will live within the \App_Data directory of our ASP.NET project. Step 5: Running our Application Now that we’ve built our application, let’s run it! We’ll browse to the /Dinners/Upcoming URL – doing so will display an empty list of upcoming dinners: You might ask – but where did it query to get the dinners from? We didn’t explicitly create a database?!? One of the cool features that EF Code-First supports is the ability to automatically create a database (based on the schema of our model classes) when the database we point it at doesn’t exist.  Above we configured  EF Code-First to point at a SQL CE database in the \App_Data\ directory of our project.  When we ran our application, EF Code-First saw that the SQL CE database didn’t exist and automatically created it for us. Step 6: Using VS 2010 SP1 to Explore our newly created SQL CE Database Click the “Show all Files” icon within the Solution Explorer and you’ll see the “NerdDinners.sdf” SQL CE database file that was automatically created for us by EF code-first within the \App_Data\ folder: We can optionally right-click on the file and “Include in Project" to add it to our solution: We can also double-click the file (regardless of whether it is added to the project) and VS 2010 SP1 will open it as a database we can edit within the “Server Explorer” tab of the IDE. Below is the view we get when we double-click our NerdDinners.sdf SQL CE file.  We can drill in to see the schema of the Dinners and RSVPs tables in the tree explorer.  Notice how two tables - Dinners and RSVPs – were automatically created for us within our SQL CE database.  This was done by EF Code First when we accessed the NerdDinners class by running our application above: We can right-click on a Table and use the “Show Table Data” command to enter some upcoming dinners in our database: We’ll use the built-in editor that VS 2010 SP1 supports to populate our table data below: And now when we hit “refresh” on the /Dinners/Upcoming URL within our browser we’ll see some upcoming dinners show up: Step 7: Changing our Model and Database Schema Let’s now modify the schema of our model layer and database, and walkthrough one way that the new VS 2010 SP1 Tooling support for SQL CE can make this easier.  With EF Code-First you typically start making database changes by modifying the model classes.  For example, let’s add an additional string property called “UrlLink” to our “Dinner” class.  We’ll use this to point to a link for more information about the event: Now when we re-run our project, and visit the /Dinners/Upcoming URL we’ll see an error thrown: We are seeing this error because EF Code-First automatically created our database, and by default when it does this it adds a table that helps tracks whether the schema of our database is in sync with our model classes.  EF Code-First helpfully throws an error when they become out of sync – making it easier to track down issues at development time that you might otherwise only find (via obscure errors) at runtime.  Note that if you do not want this feature you can turn it off by changing the default conventions of your DbContext class (in this case our NerdDinners class) to not track the schema version. Our model classes and database schema are out of sync in the above example – so how do we fix this?  There are two approaches you can use today: Delete the database and have EF Code First automatically re-create the database based on the new model class schema (losing the data within the existing DB) Modify the schema of the existing database to make it in sync with the model classes (keeping/migrating the data within the existing DB) There are a couple of ways you can do the second approach above.  Below I’m going to show how you can take advantage of the new VS 2010 SP1 Tooling support for SQL CE to use a database schema tool to modify our database structure.  We are also going to be supporting a “migrations” feature with EF in the future that will allow you to automate/script database schema migrations programmatically. Step 8: Modify our SQL CE Database Schema using VS 2010 SP1 The new SQL CE Tooling support within VS 2010 SP1 makes it easy to modify the schema of our existing SQL CE database.  To do this we’ll right-click on our “Dinners” table and choose the “Edit Table Schema” command: This will bring up the below “Edit Table” dialog.  We can rename, change or delete any of the existing columns in our table, or click at the bottom of the column listing and type to add a new column.  Below I’ve added a new “UrlLink” column of type “nvarchar” (since our property is a string): When we click ok our database will be updated to have the new column and our schema will now match our model classes. Because we are manually modifying our database schema, there is one additional step we need to take to let EF Code-First know that the database schema is in sync with our model classes.  As i mentioned earlier, when a database is automatically created by EF Code-First it adds a “EdmMetadata” table to the database to track schema versions (and hash our model classes against them to detect mismatches between our model classes and the database schema): Since we are manually updating and maintaining our database schema, we don’t need this table – and can just delete it: This will leave us with just the two tables that correspond to our model classes: And now when we re-run our /Dinners/Upcoming URL it will display the dinners correctly: One last touch we could do would be to update our view to check for the new UrlLink property and render a <a> link to it if an event has one: And now when we refresh our /Dinners/Upcoming we will see hyperlinks for the events that have a UrlLink stored in the database: Summary SQL CE provides a free, embedded, database engine that you can use to easily enable database storage.  With SQL CE 4 you can now take advantage of it within ASP.NET projects and applications (both Web Forms and MVC). VS 2010 SP1 provides tooling support that enables you to easily create, edit and modify SQL CE databases – as well as use the standard EF designer against them.  This allows you to re-use your existing skills and data knowledge while taking advantage of an embedded database option.  This is useful both for small applications (where you don’t need the scalability of a full SQL Server), as well as for development and testing scenarios – where you want to be able to rapidly develop/test your application without having a full database instance.  SQL CE makes it easy to later migrate your data to a full SQL Server or SQL Azure instance if you want to – without having to change any code in your application.  All we would need to change in the above two scenarios is the <connectionString> value within the web.config file in order to have our code run against a full SQL Server.  This provides the flexibility to scale up your application starting from a small embedded database solution as needed. 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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  • SQL SERVER – List All the DMV and DMF on Server

    - by pinaldave
    “How many DMVs and DVFs are there in SQL Server 2008?” – this question was asked to me in one of the recent SQL Server Trainings. Answer is very simple: SELECT name, type, type_desc FROM sys.system_objects WHERE name LIKE 'dm_%' ORDER BY name Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL DMV

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  • How to fix “Add Host to Workflow Farm problem” when installing Windows Azure Workflow in SharePoint2013 Preview

    - by ybbest
    Problem: When I try to configure the windows Azure workflow in SharePoint2013 preview, I got the following error see screenshot below. Detailed log can be found here. Solution: I asked the question in SharePoint StackExchange , Rajat’s help me to fix the problem .The solution for this is quite simple, instead of using the short form for your RunAs account, you should use the fully qualified name. So change administrator@YBBEST to [email protected] make the problem go away as shown below. References: How to: Set up and configure SharePoint 2013 workflows

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  • Parallelism in .NET – Part 18, Task Continuations with Multiple Tasks

    - by Reed
    In my introduction to Task continuations I demonstrated how the Task class provides a more expressive alternative to traditional callbacks.  Task continuations provide a much cleaner syntax to traditional callbacks, but there are other reasons to switch to using continuations… Task continuations provide a clean syntax, and a very simple, elegant means of synchronizing asynchronous method results with the user interface.  In addition, continuations provide a very simple, elegant means of working with collections of tasks. Prior to .NET 4, working with multiple related asynchronous method calls was very tricky.  If, for example, we wanted to run two asynchronous operations, followed by a single method call which we wanted to run when the first two methods completed, we’d have to program all of the handling ourselves.  We would likely need to take some approach such as using a shared callback which synchronized against a common variable, or using a WaitHandle shared within the callbacks to allow one to wait for the second.  Although this could be accomplished easily enough, it requires manually placing this handling into every algorithm which requires this form of blocking.  This is error prone, difficult, and can easily lead to subtle bugs. Similar to how the Task class static methods providing a way to block until multiple tasks have completed, TaskFactory contains static methods which allow a continuation to be scheduled upon the completion of multiple tasks: TaskFactory.ContinueWhenAll. This allows you to easily specify a single delegate to run when a collection of tasks has completed.  For example, suppose we have a class which fetches data from the network.  This can be a long running operation, and potentially fail in certain situations, such as a server being down.  As a result, we have three separate servers which we will “query” for our information.  Now, suppose we want to grab data from all three servers, and verify that the results are the same from all three. With traditional asynchronous programming in .NET, this would require using three separate callbacks, and managing the synchronization between the various operations ourselves.  The Task and TaskFactory classes simplify this for us, allowing us to write: var server1 = Task.Factory.StartNew( () => networkClass.GetResults(firstServer) ); var server2 = Task.Factory.StartNew( () => networkClass.GetResults(secondServer) ); var server3 = Task.Factory.StartNew( () => networkClass.GetResults(thirdServer) ); var result = Task.Factory.ContinueWhenAll( new[] {server1, server2, server3 }, (tasks) => { // Propogate exceptions (see below) Task.WaitAll(tasks); return this.CompareTaskResults( tasks[0].Result, tasks[1].Result, tasks[2].Result); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This is clean, simple, and elegant.  The one complication is the Task.WaitAll(tasks); statement. Although the continuation will not complete until all three tasks (server1, server2, and server3) have completed, there is a potential snag.  If the networkClass.GetResults method fails, and raises an exception, we want to make sure to handle it cleanly.  By using Task.WaitAll, any exceptions raised within any of our original tasks will get wrapped into a single AggregateException by the WaitAll method, providing us a simplified means of handling the exceptions.  If we wait on the continuation, we can trap this AggregateException, and handle it cleanly.  Without this line, it’s possible that an exception could remain uncaught and unhandled by a task, which later might trigger a nasty UnobservedTaskException.  This would happen any time two of our original tasks failed. Just as we can schedule a continuation to occur when an entire collection of tasks has completed, we can just as easily setup a continuation to run when any single task within a collection completes.  If, for example, we didn’t need to compare the results of all three network locations, but only use one, we could still schedule three tasks.  We could then have our completion logic work on the first task which completed, and ignore the others.  This is done via TaskFactory.ContinueWhenAny: var server1 = Task.Factory.StartNew( () => networkClass.GetResults(firstServer) ); var server2 = Task.Factory.StartNew( () => networkClass.GetResults(secondServer) ); var server3 = Task.Factory.StartNew( () => networkClass.GetResults(thirdServer) ); var result = Task.Factory.ContinueWhenAny( new[] {server1, server2, server3 }, (firstTask) => { return this.ProcessTaskResult(firstTask.Result); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, instead of working with all three tasks, we’re just using the first task which finishes.  This is very useful, as it allows us to easily work with results of multiple operations, and “throw away” the others.  However, you must take care when using ContinueWhenAny to properly handle exceptions.  At some point, you should always wait on each task (or use the Task.Result property) in order to propogate any exceptions raised from within the task.  Failing to do so can lead to an UnobservedTaskException.

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