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  • What's the "correct way" to organize this project?

    - by user571747
    I'm working on a project that allows multiple users to submit large data files and perform operations on them. The "backend" which performs these operations is written in Perl while the "frontend" uses PHP to load HTML template files and determines which content to deliver. Data is stored in a database (MySQL, SQLite, Oracle) and while there is data which has not yet been acted upon, Perl adds it to a running queue which delivers data to other threads based on system load. In addition, there may be pre- and post-processing of the data before and after the main Perl script operates (the specifications are unclear) so I may want to allow these processors to be user-selectable plugins. I had been writing this project in a more procedural fashion but I am quickly realizing the benefit of separating concerns as to limit the scope one change has on the rest of the project. I'm quite unexperienced with design patterns and am curious what the best way to proceed is. I've heard MVC thrown around quite a bit but I am unsure of how to apply it. Specifically, what are some good options to structure this code (in terms of design patterns and folder hierarchy)? How can I achieve this with both PHP and Perl while minimizing duplicated code between languages? Should I keep my PHP files in the top level so I don't have ugly paths in the URL? Also, if I want to provide interchangeable databases, does each table need its own DAO implementation?

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  • Does Zend Navigation view helper has a uri integrity check?

    - by simple
    I am kind a confused, though I am using the uri's, it doesn't render child menu items when uri has nonexisting element(madule name||controller name) <tours> <label>Tours</label> <uri>/admin/tour/index/list</uri> <class>admin-main-navigation-item ui-corner-right</class> <pages> <add> <label>Add</label> <uri>/admin/tour/index/form/type/add</uri> </add> <edit> <label>Edit</label> <uri>/admin/tour/index/list</uri> </edit> </pages> </tours> the edit and add item are not rendered because of the "admin" - is a dummy word that I use to distinguish if it is a frontend or backend of the module. any help would be appreciated, thanks

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  • CI + Joomla 1.5

    - by DMin
    Hi, This is something that I just cooked up with Joomla and CodeIgniter(CI). I Wrote my database intensive application in CodeIgniter and frontend is Joomla. I'm using Jumi(Joomla Extention) so I can include the CI files inside joomla to basically insert the content generated by CI into Joomla articles. Problem is, you can't include CI files directly using JUMI from joomla because CI tends to route the pages so instead of seeing your joomla page with the CI content, you be redirected to the CI page itself. I did a little work around for this : Made an additional page that just basically does cURL to the CI page - gets the data and echos it out. From jumi, I include this cURL page instead. Couple of questions: I've seen at least a few posts that CI + Joomla is difficult to do(link). 1) Do you see any glaring security issues or possible performance issues? 2) Do you know of a better way to implement this? 3) What do you think of this? Do you think this is a good way to do this? There is one component out there that plugs CI with Joomla but it requires you to have a fresh CI install. It allows only one controller & the download link is down as well.

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  • Representing versions of objects with CakePHP

    - by user636901
    Hi people, Have just started to get into CakePHP since a couple of weeks back. I have some experience with MVC-frameworks, but this problem holds me back a bit. I am currently working on a model foo, containing a primary id and some attributes. Since a complete history of the changes of foo is necessary, the content of foo is saved in the table foo_content. The two tables are connected through foo_content.foo_id = foo.id, in Cake with a foo hasMany foo_content-relationship. To track the versions of foo, foo_content also contains the column version, and foo itself the field currentVersion. The version is an number incremented by one everytime the user updates foo. This is an older native PHP-app btw, to be rewritten on top of Cake. 9 times out of 10 in the app, the most recent version (foo.currentVersion) is the db-entry that need to be represented in the frontend. My question is simply: is there someway of representing this directly in the model? Or does this kind of logic simply need to be defined in the controller? Most grateful for your help!

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  • Git + SoA, one repo or many?

    - by parsenome
    Normally, when I start up a new application, I'd create a new git repository for it. That's well accepted and plays nice with Github when I want to share my code. At work, I'm working in a service oriented architecture. One very common pattern is to add some code to two different applications at the same time - perhaps adding a model with a RESTful interface to one and a web frontend for managing it on another. Using separate git repositories has some warts in this case. Here are what I see as the downsides of doing separate repositories: I have to commit twice I can't correllate related commits very well No single place to go back and trace history - I'd love to be able to bring up all my commits for the day in a single place Forgetting to pull one repo or another is a gotcha On the other hand, I've used perforce a lot and its one giant repository model has lots of warts too. Perforce has features designed to let help you with those, git doesn't. Has anyone else run into this situation? How did you handle it? What worked well, and what didn't?

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  • What is a good RPC model for building a AJAX web app using PHP & JS?

    - by user366152
    I'm new to writing AJAX applications. I plan on using jQuery on the client side while PHP on the server side. I want to use something like XML-RPC to simplify my effort in calling server-side code. Ideally, I wouldn't care whether the transport layer uses XML or JSON or a format more optimized for the wire. If I was writing a console app I'd use some tool to generate function stubs which I would then implement on the RPC server while the client would natively call into those stubs. This provides a clean separation. Is there something similar available in the AJAX world? While on this topic, how would I proceed with session management? I would want it to be as transparent as possible. For example, if I try to hit an RPC end-point which needs a valid session, it should reject the request if the client doesn't pass a valid session cookie. This would really ease my application development. I'd then have to simply handle the frontend using native JS functions. While on the backend, I can simply implement the RPC functions. BTW I dont wish to use Google Web Toolkit. My app wont be extremely heavy on AJAX.

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  • How to document an existing small web site (web application), inside and out?

    - by Ricket
    We have a "web application" which has been developed over the past 7 months. The problem is, it was not really documented. The requirements consisted of a small bulleted list from the initial meeting 7 months ago (it's more of a "goals" statement than software requirements). It has collected a number of features which stemmed from small verbal or chat discussions. The developer is leaving very soon. He wrote the entire thing himself and he knows all of the quirks and underlying rules to each page, but nobody else really knows much more than the user interface side of it; which of course is the easy part, as it's made to be intuitive to the user. But if someone needs to repair or add a feature to it, the entire thing is a black box. The code has some minimal comments, and of course the good thing about web applications is that the address bar points you in the right direction towards fixing a problem or upgrading a page. But how should the developer go about documenting this web application? He is a bit lost as far as where to begin. As developers, how do you completely document your web applications for other developers, maintainers, and administrative-level users? What approach do you use, where do you start, do you have a template? An idea of magnitude: it uses PHP, MySQL and jQuery. It has about 20-30 main (frontend) files, along with about 15 included files and a couple folders of some assets. So overall it's a pretty small application. It interfaces with 7 MySQL tables, each one well-named, so I think the database end is pretty self-explanatory. There is a config.inc.php file with definitions of consts like the MySQL user details, some from/to emails, and URLs which PHP uses to insert into emails and pages (relative and absolute paths, basiecally). There is some AJAX via jQuery. Please comment if there is any other information that would help you help me and I will be glad to edit it in.

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  • Replacing mysql user authentication with openid

    - by David
    So, I'm working with a really old system which uses a person's mysql database credentials to authenticate to a web site (the database was originally only accessed from the command line, but is now accessed from a php frontend). Because of some internal reasons (and to preserve the user's history), I have to leave the old authentication intact. I've been charged with adding openid authentication to this system. Somehow I need to be able to retrieve a users mysql username and password upon logging into the site through openid (using the Zend framework, by the way). I've thought of simply requiring registration at the first login, where the user must provide their mysql credentials, but I'd rather not store the password plain text. I've also considered blanking everyone's mysql passwords, and just setting the user's mysql username manually (rather than having the user provide this, since they could provide any username). This is turning into a security nightmare. Does anyone have any suggestions for alternatives? This is running on a Linux server, by the way. Also, I can't use mysql pluggable authentication because the mysql version is 5.0 (pluggable authentication requires mysql 5.5), and no, I can't update it.

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  • Loading a view routed by a URL parameter (e.g., /users/:id) in MEAN stack

    - by Matt Rowles
    I am having difficulties with trying to load a user by their id, for some reason my http.get call isn't hitting my controller. I get the following error in the browser console: TypeError: undefined is not a function at new <anonymous> (http://localhost:9000/scripts/controllers/users.js:10:8) Update I've fixed my code up as per comments below, but now my code just enters an infinite loop in the angular users controllers (see code below). I am using the Angular Express Generator for reference Backend - nodejs, express, mongo routes.js: // not sure if this is required, but have used it before? app.param('username', users.show); app.route('/api/users/:username') .get(users.show); controller.js: // This never gets hit exports.show = function (req, res, next, username) { User.findOne({ username: username }) .exec(function (err, user) { req.user = user; res.json(req.user || null); }); }; Frontend - angular app.js: $routeProvider .when('/users/:username', { templateUrl: function( params ){ return 'users/view/' + params.username; }, controller: 'UsersCtrl' }) services/user.js: angular.module('app') .factory('User', function ($resource) { return $resource('/api/users/:username', { username: '@username' }, { update: { method: 'PUT', params: {} }, get: { method: 'GET', params: { username:'username' } } }); }); controllers/users.js: angular.module('app') .controller('UsersCtrl', ['$scope', '$http', '$routeParams', '$route', 'User', function ($scope, $http, $routeParams, $route, User) { // this returns the error above $http.get( '/api/users/' + $routeParams.username ) .success(function( user ) { $scope.user = user; }) .error(function( err) { console.log( err ); }); }]); If it helps, I'm using this setup

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  • PHP site scheduling Java execution?

    - by obfuscation
    I'm trying to get started on combining my (slightly limited) PHP experience with my (better) Java experience, in a project where I need to allow uploads of Java source files to the server, which the server then executes Javac on to compile it. Then, at a set time (e.g. specified on upload) I need to run that once on the server, which will generate some database info for the PHP site to display. To describe my current programming abilities- I have made many desktop Java programs, and am confident in 'pure' Java, but so far have only undertaken a couple of PHP projects (including using the CodeIgniter framework). My motivation for using PHP as the frontend is because I know it is very fast, lightweight and I will be able to display the results I need very easily with it (simple DB readout). Ideally, the technology used should be able to be developed on a localhost (e.g. WAMP, Tomcat etc..) Is there any advice which you could give on what technology I should consider to use to bridge this gap, and what resources could help in using that technology? I have looked at a few, but have struggled to find documentation helping in achieving what I need.

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  • GCC 4.2.1 Compiling on Cygwin(Win7 64bit) for iPhone [closed]

    - by Kenneth Noland
    Hey This is going to take a long while to explain, but the short version is that I am currently attempting to compile the LLVM GCC frontend for ARMv7 to compile apps for the Cortex-A8(iPhone 3GS). I'm running into an error from LD when compiling libgcc(part of the gcc compilation process) that has been driving me mad! The command is this: /usr/llvm-gcc-4.2-2.8.source/build/./gcc/xgcc \ -B/usr/llvm-gcc-4.2_2.8.source/build/./gcc \ -B/usr/local/arm-apple-darwin/bin \ -B/usr/local/arm-apple-darwin/lib \ -isystem /usr/local/arm-apple-darwin/include \ -isystem /usr/local/arm-apple-darwin/sys-include \ -O2 -g -W -Wall -Wwrite-strings -wstrict-prototypes -Wmissing-prototypes -Wold-style-definition -fno-inline -dynamiclib -nodefaultlibs -W1,-dead_strip \ -marm \ -install_name /usr/local/arm-apple-darwin/lib/libgcc_s.1.dylib \ -single_module -o ./libgcc_s.1.dylib.tmp \ -W1,-exported_symbols_list,libgcc/./libgcc.map -compatibility_version 1 -current_version 1.0 -DIN_GCC -DCROSS_DIRECTORY_STRUCTURE -DHAVE_GTHR_DEFAULT -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED -Dinhibit_libc \ ... long list of .o files ... \ -lc And the result is typically a lot of undefined references to malloc, free, exit, etc. which typically indicate that libc is not getting compiled in. After going through the list of errors that ld is throwing, I see at the top that it is attempting to pull in /usr/lib/libc.a and complains that it is not the correct platform. Okay, that makes sense, so I spent 5 minutes on google and found an answer. Turns out that if I copy the libSystem.dylib and rename it to libc.dylib, that should solve the problem, but it doesn't. I couldn't find a copy of that file on my phone, so I pulled it directly from the SDK. I then get this strange error: ld64: in /usr/local/arm-apple-darwin/lib/libc.dylib, can't re-map file, errno=22 At this point, I did everything I could think of. I grabbed a fresh copy of my /usr/lib folder from my iphone and confirmed that libSystem.dylib(and libSystem.B.dylib) wasn't there. I unpacked the raw .ipsw package for iOS 4.2.1 and once again, I could not find a copy of libSystem.dylib there either. I unpacked the iPhoneSDK and MacOS SDK and I managed to find a copy of it in both, but that error just kept persisting. I copied libSystem.dylib, libSystem.B.dylib, tried all sorts of combinations of renaming to libc.dylib and still nothing but errors. I can't find a way to get it to recognize the file and link against it. I also tried linking against the libc.a located in the iphone SDK and that didn't work either. I checked what ./xgcc was firing off, and it was my freshly built copy of arm-apple-darwin-ld64 which should be fine. A little bit of background here. I built LLVM+Clang 2.8 with no errors, and I rebuilt the ODCCTools with some light modifications to get it to compile on Cygwin(I'll post my changes in a patch along with a tutorial if I can get this to work). I also grabbed the iphone-dev "includes" and "csu" project and those completed successfully, although there really is no point to them since I can't get it to link against crt0.a. I'm running out of ideas here. Can anyone help me out on this?

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  • Java Spotlight Episode 76: Pro Java FX2 - A Definative Guide to Rich Clients with Java Technology

    - by Roger Brinkley
    Tweet An interview with the authors of Pro Java FX2: A Definative Guide to Rich Clients with Java Technology. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link:  Java Spotlight Podcast in iTunes. Show Notes News Angela Caicedo has created 3 new Java FX screen cast videos on java UTube channel: Part 1: Building your First Java FX Application with Netbeans 7.1, Part 2: Building your First Java FX Application with Netbeans 7.1, and Getting Started with Scene Builder.  Events March 26-29, EclipseCon, Reston, USA March 27, Virtual Developer Days - Java (Asia Pacific (English)),9:30 am to 2:00pm IST / 12:00pm to 4.30pm SGT  / 3.00pm - 7.30pm AEDT April 4-5, JavaOne Japan, Tokyo, Japan April 12, GreenJUG, Greenville, SC April 17-18, JavaOne Russia, Moscow Russia April 18–20, Devoxx France, Paris, France April 26, Mix-IT, Lyon, France, May 3-4, JavaOne India, Hyderabad, India Feature InterviewPro JavaFX 2: A Definitive Guide to Rich Clients with Java Technology is available from Amazon.com in either paperback or on the Kindle.James L. (Jim) Weaver is a Java and JavaFX developer, author, and speaker with a passion for helping rich-client Java and JavaFX become preferred technologies for new application development. Books that Jim has authored include Inside Java, Beginning J2EE, and Pro JavaFX Platform, with the latter being updated to cover JavaFX 2.0. His professional background includes 15 years as a systems architect at EDS, and the same number of years as an independent developer. Jim is an international speaker at software technology conferences, including the JavaOne conferences in San Francisco and São Paulo. Jim blogs at http://javafxpert.com, tweets @javafxpert. Weiqi Gao is a principal software engineer with Object Computing, Inc., in St. Louis, MO. He has more than 18 years of software development experience and has been using Java technology since 1998. He is interested in programming languages, object-oriented systems, distributed computing, and graphical user interfaces. He is a presenter and a member of the steering committee of the St. Louis Java Users Group. Weiqi holds a PhD in mathematics. Stephen Chin is chief agile methodologist at GXS and a technical expert in client UI technologies. He is lead author on the Pro Android Flash title and coauthored the Pro JavaFX Platform title, which is the leading technical reference for JavaFX. In addition, Stephen runs the very successful Silicon Valley JavaFX User Group, which has hundreds of members and tens of thousands of online viewers. Finally, he is a Java Champion, chair of the OSCON Java conference, and an internationally recognized speaker featured at Devoxx, Codemash, AnDevCon, Jazoon, and JavaOne, where he received a Rock Star Award. Stephen can be followed on twitter @steveonjava and reached via his blog: http://steveonjava.com.Dean Iverson has been writing software professionally for more than 15 years. He is employed by the Virginia Tech Transportation Institute, where he is a rich client application developer. He also has a small software consultancy called Pleasing Software Solutions, which he cofounded with his wife. Johan Vos started to work with Java in 1995. As part of the Blackdown team, he helped port Java to Linux. With LodgON, the company he cofounded, he has been mainly working on Java-based solutions for social networking software. Because he can't make a choice between embedded development and enterprise development, his main focus is on end-to-end Java, combining the strengths of backend systems and embedded devices. His favorite technologies are currently Java EE/Glassfish at the backend and JavaFX at the frontend. Johan's blog can be followed at http://blogs.lodgon.com/johan, he tweets at http://twitter.com/johanvos. Mail Bag What’s Cool Gerrit Grunwald's SteelSeries FX Experience Tools Canned Animations ComboBox

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  • Growing Talent

    The subtitle of Daniel Coyles intriguing book The Talent Code is Greatness Isnt Born. Its Grown. Heres How. The Talent Code proceeds to layout a theory of how expertise can be cultivated through specific practices that encourage the growth of myelin in the brain. Myelin is a material that is produced and wraps around heavily used circuits in the brain, making them more efficient. Coyle uses an analogy that geeks will appreciate. When a circuit in the brain is used a lot (i.e. a specific action is repeated), the myelin insulates that circuit, increasing its bandwidth from telephone over copper to high speed broadband. This leads to the funny phenomenon of effortless expertise. Although highly skilled, the best players make it look easy. Coyle provides some biological backing for the long held theory that it takes 10,000 hours of practice to achieve mastery over a given subject. 10,000 hours or 10 years, as in, Teach Yourself Programming in Ten Years and others. However, it is not just that more hours equals more mastery. The other factors that Coyle identifies includes deep practice, practice which crucially involves drills that are challenging without being impossible. Another way to put it is that every day you spend doing only tasks you find monotonous and automatic, you are literally stagnating your brains development! Perhaps Coyles subtitle, needs one more phrase, Greatness Isnt Born. Its Grown. Heres How. And oh yeah, its not easy. Challenging yourself, continuing to persist in the face of repeated failures, practicing every day is not easy. As consultants, we sell our expertise, so it makes sense that we plan projects so that people can play to their strengths. At the same time, an important part of our culture is constant improvement, challenging yourself to be better. And the balancing contest ensues. I just finished working on a proof of concept (POC) we did for a project we are bidding on. Completely time boxed, so our team naturally split responsibilities amongst ourselves according to who was better at what. I must have been pretty bad at the other components, as I found myself working on the user interface, not my usual strength. The POC had a website frontend, and one thing I do know is HTML. After starting out in pure ASP.NET WebForms, I got frustrated as time was ticking, I knew what I wanted in HTML, but I couldnt coax the right output out of the ASP.NET controls. I needed two or three elements on the screen that were identical in layout, with different content. With a backup plan in  of writing the HTML into the response by hand, I decided to challenge myself a bit and see what I could do in an hour or two using the Microsoft submitted jQuery micro-templating JavaScript library. This risk paid off. I was able to quickly get the user interface up and running, responsive to the JSON data we were working with. I felt energized by the double win of getting the POC ready and learning something new. Opportunities  specifically like this POC dont come around often, but the takeaway is that while it wont be easy, there are ways to generate your own opportunities to grow towards greatness.Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Should I manage authentication on my own if the alternative is very low in usability and I am already managing roles?

    - by rumtscho
    As a small in-house dev department, we only have experience with developing applications for our intranet. We use the existing Active Directory for user account management. It contains the accounts of all company employees and many (but not all) of the business partners we have a cooperation with. Now, the top management wants a technology exchange application, and I am the lead dev on the new project. Basically, it is a database containing our know-how, with a web frontend. Our employees, our cooperating business partners, and people who wish to become our cooperating business partners should have access to it and see what technologies we have, so they can trade for them with the department which owns them. The technologies are not patented, but very valuable to competitors, so the department bosses are paranoid about somebody unauthorized gaining access to their technology description. This constraint necessitates a nightmarishly complicated multi-dimensional RBAC-hybrid model. As the Active Directory doesn't even contain all the information needed to infer the roles I use, I will have to manage roles plus per-technology per-user granted access exceptions within my system. The current plan is to use Active Directory for authentication. This will result in a multi-hour registration process for our business partners where the database owner has to manually create logins in our Active Directory and send them credentials. If I manage the logins in my own system, we could improve the usability a lot, for example by letting people have an active (but unprivileged) account as soon as they register. It seems to me that, after I am having a users table in the DB anyway (and managing ugly details like storing historical user IDs so that recycled user IDs within the Active Directory don't unexpectedly get rights to view someone's technologies), the additional complexity from implementing authentication functionality will be minimal. Therefore, I am starting to lean towards doing my own user login management and forgetting the AD altogether. On the other hand, I see some reasons to stay with Active Directory. First, the conventional wisdom I have heard from experienced programmers is to not do your own user management if you can avoid it. Second, we have code I can reuse for connection to the active directory, while I would have to code the authentication if done in-system (and my boss has clearly stated that getting the project delivered on time has much higher priority than delivering a system with high usability). Third, I am not a very experienced developer (this is my first lead position) and have never done user management before, so I am afraid that I am overlooking some important reasons to use the AD, or that I am underestimating the amount of work left to do my own authentication. I would like to know if there are more reasons to go with the AD authentication mechanism. Specifically, if I want to do my own authentication, what would I have to implement besides a secure connection for the login screen (which I would need anyway even if I am only transporting the pw to the AD), lookup of a password hash and a mechanism for password recovery (which will probably include manual identity verification, so no need for complex mTAN-like solutions)? And, if you have experience with such security-critical systems, which one would you use and why?

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  • Admin Panel like Custom Framework

    - by bhuvin
    I want to Create a Framework , like Admin panel , which can rule almost all the aspects of what is shown on the frontend. For an (most basic) example: If suppose the links which are to be shown in a navigation area is passed from the server, with the order and the url , etc. The whole aim is to save the time on the tedious tasks. You can just start creating menus and start assigning pages to it. Give a url, actual files which are to be rendered (in case of static files.), in case of dynamic files, giving the file accordingly. And all this is fully server side manageable using different portlets, sort of things. So basic Roadmap is having : Areas like: Header Area - Which can contain logos, links etc. Navigation Area - Which can contains links and submenus. Content Area - Now this is where the tricky part is that that it has zones like: left, center & right. It contains Order in which it has to be displayed. So, when someday we want to change the way the articles appear on the page, we can do so easily, without any deployments. Now these zones can have n number of internal elements, like the word cloud, or the advertisement area. Footer Area: Again similar as Header Area. Currently there is a preexisting custom framework, which uses XSLT files for pulling out data from the server side. And it has the above capabilities. For example: If there's a grid it will be having a <table> tag embedded in the XSLT file. Now whatever might be the source of the data, we serialize this as XML and give it to the XSLT file and the html is derived from this and is appended to the layer in a page. The problem with this approach is: The XSLT conversion is occurring on the server side, so the server is responsible for getting the data, running XSLT transform, and append the html generated to the layer div. So, according to me, firstly this isn't the server's concern to do so. Secondly for larger applications this might be slower. Debugging isn't possible for XSLT transformation. So, whenever we face problems with data its always a bit of a trial & error method. Maintaining it is a bit of an eerie job i.e. styling changes, and other stuff. Adding dynamic values. Like JavaScript can't actually be very easily used in this. Secondly, we can't use JQuery or any other libraries with this since this is all occurring on the server. For now what I have thought about is using Templating - Javascript - JSON combination in place of XSLT, this will be offloaded to the client and the rendering will take place accordingly. This could solve the above problems and also could add mobile support for the same. Only problem which I could think of is that: It is much work and adding new portlets on the go needs to be looked into. What could be the alternatives for this? What kind of problems are there with the JavaScript approach? What are the different ways to implement the same? Are there any existing frameworks for similar usage?

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  • multiple webapps in tomcat -- what is the optimal architecture?

    - by rvdb
    I am maintaining a growing base of mainly Cocoon-2.1-based web applications [http://cocoon.apache.org/2.1/], deployed in a Tomcat servlet container [http://tomcat.apache.org/], and proxied with an Apache http server [http://httpd.apache.org/docs/2.2/]. I am conceptually struggling with the best way to deploy multiple web applications in Tomcat. Since I'm not a Java programmer and we don't have any sysadmin staff I have to figure out myself what is the most sensible way to do this. My setup has evolved through 2 scenarios and I'm considering a third for maximal separation of the distinct webapps. [1] 1 Tomcat instance, 1 Cocoon instance, multiple webapps -tomcat |_ webapps |_ webapp1 |_ webapp2 |_ webapp[n] |_ WEB-INF (with Cocoon libs) This was my first approach: just drop all web applications inside a single Cocoon webapps folder inside a single Tomcat container. This seemed to run fine, I did not encounter any memory issues. However, this poses a maintainability drawback, as some Cocoon components are subject to updates, which often affect the webapp coding. Hence, updating Cocoon becomes unwieldy: since all webapps share the same pool of Cocoon components, updating one of them would require the code in all web applications to be updated simultaneously. In order to isolate the web applications, I moved to the second scenario. [2] 1 Tomcat instance, each webapp in its dedicated Cocoon environment -tomcat |_ webapps |_ webapp1 | |_ WEB-INF (with Cocoon libs) |_ webapp1 | |_ WEB-INF (with Cocoon libs) |_ webapp[n] |_ WEB-INF (with Cocoon libs) This approach separates all webapps into their own Cocoon environment, run inside a single Tomcat container. In theory, this works fine: all webapps can be updated independently. However, this soon results in PermGenSpace errors. It seemed that I could manage the problem by increasing memory allocation for Tomcat, but I realise this isn't a structural solution, and that overloading a single Tomcat in this way is prone to future memory errors. This set me thinking about the third scenario. [3] multiple Tomcat instances, each with a single webapp in its dedicated Cocoon environment -tomcat |_ webapps |_ webapp1 |_ WEB-INF (with Cocoon libs) -tomcat |_ webapps |_ webapp2 |_ WEB-INF (with Cocoon libs) -tomcat |_ webapps |_ webapp[n] |_ WEB-INF (with Cocoon libs) I haven't tried this approach, but am thinking of the $CATALINA_BASE variable. A single Tomcat distribution can be multiply instanciated with different $CATALINA_BASE environments, each pointing to a Cocoon instance with its own webapp. I wonder whether such an approach could avoid the structural memory-related problems of approach [2], or will the same issues apply? On the other hand, this approach would complicate management of the Apache http frontend, as it will require the AJP connectors of the different Tomcat instances to be listening at different ports. Hence, Apache's worker configuration has to be updated and reloaded whenever a new webapp (in its own Tomcat instance) is added. And there seems no way to reload worker.properties without restarting the entire Apache http server. Is there perhaps another / more dynamic way of 'modularizing' multiple Tomcat-served webapps, or can one of these scenarios be refined? Any thoughts, suggestions, advice much appreciated. Ron

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  • HAproxy roundrobin balancing does not appear to be distributing evently

    - by andrew
    Hello, I know that with loaded servers, roundrobin in HAproxy (1.4.4) does not evenly distribute, but my servers are currently getting NO traffic (test setup), and roundrobin balancing does www1,www1,www1,www1,www1,...www2,www2,www2,...,www1... I'm verifying this by having the script being run on each server cat /etc/HOSTNAME (slackware). I need to have it switch back and forth each time to test some session stuff (stored in shared memcached) but am having trouble getting it to switch between my two web servers on each request. global log 127.0.0.1 local0 warning maxconn 4096 chroot /usr/share/haproxy pidfile /var/run/haproxy.pid uid 99 gid 99 daemon defaults balance roundrobin fullconn 100 maxconn 4096 mode http option dontlognull option http-server-close option forwardfor option redispatch retries 3 timeout connect 5000 timeout client 20000 timeout server 60000 timeout queue 60000 stats enable stats uri /haproxy stats auth ***:*** frontend www *:80 log global acl is_upload hdr_dom(host) -i uploads.site.com acl is_api hdr_dom(host) -i api.site.com acl is_dev hdr_dom(host) -i dev.site.com acl is_apidev hdr_dom(host) -i apidev.site.com use_backend uploads.site.com if is_upload use_backend api.site.com if is_api use_backend dev.site.com if is_dev !is_apidev default_backend site.com backend site.com option httpchk HEAD /alive.php HTTP/1.1\r\nHost:site.com server www1 1.1.1.1:8080 weight 10 minconn 5 maxconn 25 check inter 2000 rise 2 fall 2 server www2 1.1.1.2:8080 weight 10 minconn 5 maxconn 25 check inter 2000 rise 2 fall 2 backend api.site.com option httpchk HEAD /alive.php HTTP/1.1\r\nHost:api.site.com server www1 1.1.1.1:8080 weight 10 minconn 5 maxconn 25 check inter 2000 rise 2 fall 2 server www2 1.1.1.2:8080 weight 10 minconn 5 maxconn 25 check inter 2000 rise 2 fall 2 backend dev.site.com option httpchk HEAD /alive.php HTTP/1.1\r\nHost:dev.site.com server www1 1.1.1.1:8080 weight 10 minconn 5 maxconn 25 check inter 2000 rise 2 fall 2 server www2 1.1.1.2:8080 weight 10 minconn 5 maxconn 25 check inter 2000 rise 2 fall 2 backend uploads.site.com option httpchk HEAD /alive.php HTTP/1.1\r\nHost:uploads.site.com server www1 1.1.1.1:8080 weight 10 minconn 5 maxconn 25 check inter 2000 rise 2 fall 2 server www2 1.1.1.2:8080 backup weight 10 minconn 5 maxconn 25 check inter 2000 rise 2 fall 2 So basically, I have some different back-ends (I've verified the ACLs are working), with the default option "roundrobin" selected. I've tried removing weights, removing the minconn/maxconn/fullconn attributes for all servers (not just the backend I'm testing), tried removing the ACLs, etc. I've been testing on dev.site.com BTW. Anyone see a reason why I can't get something like www1,www2,www1,www2,...? Also, this is one of my first questions on here, so please let me know if I left anything needed out of my post. Thanks!

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  • What is the coolest thing you can do in <10 lines of simple code? Help me inspire beginners!

    - by Tom Ritter
    I'm looking for the coolest thing you can do in a few lines of simple code. I'm sure you can write a Mandelbrot set in Haskell in 15 lines but it's difficult to follow. My goal is to inspire students that programming is cool. We know that programming is cool because you can create anything you imagine - it's the ultimate creative outlet. I want to inspire these beginners and get them over as many early-learning humps as I can. Now, my reasons are selfish. I'm teaching an Intro to Computing course to a group of 60 half-engineering, half business majors; all freshmen. They are the students who came from underprivileged High schools. From my past experience, the group is generally split as follows: a few rock-stars, some who try very hard and kind of get it, the few who try very hard and barely get it, and the few who don't care. I want to reach as many of these groups as effectively as I can. Here's an example of how I'd use a computer program to teach: Here's an example of what I'm looking for: a 1-line VBS script to get your computer to talk to you: CreateObject("sapi.spvoice").Speak InputBox("Enter your text","Talk it") I could use this to demonstrate order of operations. I'd show the code, let them play with it, then explain that There's a lot going on in that line, but the computer can make sense of it, because it knows the rules. Then I'd show them something like this: 4(5*5) / 10 + 9(.25 + .75) And you can see that first I need to do is (5*5). Then I can multiply for 4. And now I've created the Object. Dividing by 10 is the same as calling Speak - I can't Speak before I have an object, and I can't divide before I have 100. Then on the other side I first create an InputBox with some instructions for how to display it. When I hit enter on the input box it evaluates or "returns" whatever I entered. (Hint: 'oooooo' makes a funny sound) So when I say Speak, the right side is what to Speak. And I get that from the InputBox. So when you do several things on a line, like: x = 14 + y; You need to be aware of the order of things. First we add 14 and y. Then we put the result (what it evaluates to, or returns) into x. That's my goal, to have a bunch of these cool examples to demonstrate and teach the class while they have fun. I tried this example on my roommate and while I may not use this as the first lesson, she liked it and learned something. Some cool mathematica programs that make beautiful graphs or shapes that are easy to understand would be good ideas and I'm going to look into those. Here are some complicated actionscript examples but that's a bit too advanced and I can't teach flash. What other ideas do you have?

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  • Code golf: Word frequency chart

    - by ChristopheD
    The challenge: Build an ASCII chart of the most commonly used words in a given text. The rules: Only accept a-z and A-Z (alphabetic characters) as part of a word. Ignore casing (She == she for our purpose). Ignore the following words (quite arbitary, I know): the, and, of, to, a, i, it, in, or, is Clarification: considering don't: this would be taken as 2 different 'words' in the ranges a-z and A-Z: (don and t). Optionally (it's too late to be formally changing the specifications now) you may choose to drop all single-letter 'words' (this could potentially make for a shortening of the ignore list too). Parse a given text (read a file specified via command line arguments or piped in; presume us-ascii) and build us a word frequency chart with the following characteristics: Display the chart (also see the example below) for the 22 most common words (ordered by descending frequency). The bar width represents the number of occurences (frequency) of the word (proportionally). Append one space and print the word. Make sure these bars (plus space-word-space) always fit: bar + [space] + word + [space] should be always <= 80 characters (make sure you account for possible differing bar and word lenghts: e.g.: the second most common word could be a lot longer then the first while not differing so much in frequency). Maximize bar width within these constraints and scale the bars appropriately (according to the frequencies they represent). An example: The text for the example can be found here (Alice's Adventures in Wonderland, by Lewis Carroll). This specific text would yield the following chart: _________________________________________________________________________ |_________________________________________________________________________| she |_______________________________________________________________| you |____________________________________________________________| said |____________________________________________________| alice |______________________________________________| was |__________________________________________| that |___________________________________| as |_______________________________| her |____________________________| with |____________________________| at |___________________________| s |___________________________| t |_________________________| on |_________________________| all |______________________| this |______________________| for |______________________| had |_____________________| but |____________________| be |____________________| not |___________________| they |__________________| so For your information: these are the frequencies the above chart is built upon: [('she', 553), ('you', 481), ('said', 462), ('alice', 403), ('was', 358), ('that ', 330), ('as', 274), ('her', 248), ('with', 227), ('at', 227), ('s', 219), ('t' , 218), ('on', 204), ('all', 200), ('this', 181), ('for', 179), ('had', 178), (' but', 175), ('be', 167), ('not', 166), ('they', 155), ('so', 152)] A second example (to check if you implemented the complete spec): Replace every occurence of you in the linked Alice in Wonderland file with superlongstringstring: ________________________________________________________________ |________________________________________________________________| she |_______________________________________________________| superlongstringstring |_____________________________________________________| said |______________________________________________| alice |________________________________________| was |_____________________________________| that |______________________________| as |___________________________| her |_________________________| with |_________________________| at |________________________| s |________________________| t |______________________| on |_____________________| all |___________________| this |___________________| for |___________________| had |__________________| but |_________________| be |_________________| not |________________| they |________________| so The winner: Shortest solution (by character count, per language). Have fun! Edit: Table summarizing the results so far (2012-02-15) (originally added by user Nas Banov): Language Relaxed Strict ========= ======= ====== GolfScript 130 143 Perl 185 Windows PowerShell 148 199 Mathematica 199 Ruby 185 205 Unix Toolchain 194 228 Python 183 243 Clojure 282 Scala 311 Haskell 333 Awk 336 R 298 Javascript 304 354 Groovy 321 Matlab 404 C# 422 Smalltalk 386 PHP 450 F# 452 TSQL 483 507 The numbers represent the length of the shortest solution in a specific language. "Strict" refers to a solution that implements the spec completely (draws |____| bars, closes the first bar on top with a ____ line, accounts for the possibility of long words with high frequency etc). "Relaxed" means some liberties were taken to shorten to solution. Only solutions shorter then 500 characters are included. The list of languages is sorted by the length of the 'strict' solution. 'Unix Toolchain' is used to signify various solutions that use traditional *nix shell plus a mix of tools (like grep, tr, sort, uniq, head, perl, awk).

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  • Surface development: it&rsquo;s just like software development

    - by Dennis Vroegop
    Surface is magic. Everyone using it seems to think that way. And I have to be honest, after working for almost 2 years with the platform I still get that special feeling the moment I turn on the unit to do some more work. The whole user experience, the rich environment of the SDK, the touch, even the look and feel of the Surface environment is so much different from the stuff I’ve been working on all my career that I am still bewildered by it. But… and this is a big but.. in the end we’re still talking about a computer and that needs software to become useful. Deep down the magic of the Surface unit there is a PC somewhere, running Windows Vista and the .net framework 3.5. When you write that magic software that makes the platform come alive you’re still working with .net, WPF/XNA, C#, VB.Net and all those other tools and technologies you know so well. Sure, the whole user experience is different from what you’ve known. And the way of thinking about users, their interaction and the positioning of screen elements requires a whole new paradigm. And that takes time. It took me about half a year before I had the feeling I got it nailed down. But when that moment came (about 18 months ago…) I realized that everything I had learned so far on software development still is true when it comes to Surface. The last 6 months I have been working with some people with a different background to start a new company. The idea was that the new company would be focussing on Surface and Surface only. These people come from a marketing background and had some good ideas for some applications. And I have to admit: their ideas were good. Very good. Where it all fell down of course is that these ideas need to be implemented in a piece of software. And creating great software takes skilled developers and a lot of time and money. That’s where things went wrong: the marketing guys didn’t realize and didn’t want to realize that software development is a job that takes skill. You can’t just hire a bunch of developers and expect them to deliver the best sort of software, especially not when it comes to Surface. I tried to explain that yes, their User Interface in Photoshop looked great, but no: I couldn’t develop an application like that in a weeks time. Even worse: the while backend of the software (WCF for communications, SQL Server for the database, etc) would take a lot more time than the frontend. They didn’t understand. It took them a couple of days to drawn the UI in Photoshop so in Blend I should be able to build the software in about the same amount of time. Well, you and I know that it doesn’t work that way. Software is hard to write, and even harder to write well, and it takes skill and dedication. It’s not something you can do as fast as you can draw a mock up for a Surface application in Photohop. The same holds true for web applications of course. A lot of designers there fail to appreciate the hard work that goes into writing the plumbing for a good web app that can handle thousands of users. Although the UI is very important, it’s not all there is to it. And in Surface development this is the same. The UI should create the feeling of magic, but the software behind it is what makes it come alive. And that takes time. A lot of time. So brush of you skills and don’t throw them away if you start developing for Surface. Because projects (and colaborations) can fail there as hard as they can in any other area of software development. On a side note: we decided to stop the colaboration (something the other parties involved didn’t appreciate and were very angry about) and decided to hire a designer for the Surface projects. The focus is back where it belongs: on the software development we know so well and have been doing very well for 13 years. UI is just a part of the whole project and not the end product. So my company Detrio is still going strong when it comes to develivering Surface solutions but once again from a technological background, not a marketing background.

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  • Play Your Favorite DOS Games in XP, Vista, and Windows 7

    - by Matthew Guay
    Want to take a trip down memory lane with old school DOS games?  D-Fend Reloaded makes it easy for you to play your favorite DOS games directly on XP, Vista, and Windows 7. D-Fend Reloaded is a great frontend for DOSBox, the popular DOS emulator.  It lets you install and run many DOS games and applications directly from its interface without ever touching a DOS prompt.  It works great on XP, Vista, and Windows 7 32 & 64-bit versions.   Getting Started Download D-Fend Reloaded (link below), and install with the default settings.  You don’t need to install DOSBox, as D-Fend Reloaded will automatically install all the components you need to run DOS games on Windows. D-Fend Reloaded can also be installed as a portable application, so you can run it from a flash drive on any Windows computer by selecting User defined installation. Then select Portable mode installation. Once D-Fend Reloaded is installed, you can go ahead and open the program. Then simply click “Accept all settings” to apply the default settings.   D-Fend is now ready to run all of your favorite DOS games. Installing DOS Games and Applications: To install a DOS game or application, simply drag-and-drop a zip file of the app into D-Fend Reloaded’s window.  D-Fend Reloaded will automatically extract the program… Then will ask you to name the application and choose where to store it — by default it uses the name of the DOS app. Now you’ll see a new entry for the app you just installed.  Simply double-click to run it.   D-Fend will remind you that you can switch out of fullscreen mode by pressing Alt+Enter, and can also close the DOS application by pressing Ctrl+F9.  Press Ok to run the program. Here we’re running Ms. PacPC, a remake of the classic game Ms. Pac-Man, in full-screen mode.  All features work automatically, including sound, and you never have to setup anything from DOS command line — it just works. Here it’s in windowed mode running on Windows 7. Please note that your color scheme may change to Windows Basic while running DOS applications. You can run DOS application just as easily.  Here’s Word 5.5 running in in DOSBox through D-Fend Reloaded… Game Packs: Want to quickly install many old DOS freeware and trial games?  D-Fend Reloaded offers several game packs that let you install dozens of DOS games with only four clicks…just download and run the game pack installer of your choice (link below). Now you’ve got a selection of DOS games to choose from. Here’s a group of poor lemmings walking around … in Windows 7. Conclusion D-Fend Reloaded gives you a great way to run your favorite DOS games and applications directly from XP, Vista, and Windows 7.  Give it a try, and relive your DOS days from the comfort of your Windows desktop. What were some of your favorite DOS games and applications? Leave a comment and let us know. Links Download D-Fend Reloaded Download DOS game packs for D-Fend Reloaded Download Ms. Pac-PC Similar Articles Productive Geek Tips Friday Fun: Get Your Mario OnFriday Fun: Go Retro with PacmanThursday’s Pre-Holiday Lazy Links RoundupFriday Fun: Five More Time Wasting Online GamesFriday Fun: Holiday Themed Games TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional The Growth of Citibank Quickly Switch between Tabs in IE Windows Media Player 12: Tweak Video & Sound with Playback Enhancements Own a cell phone, or does a cell phone own you? Make your Joomla & Drupal Sites Mobile with OSMOBI Integrate Twitter and Delicious and Make Life Easier

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  • International Radio Operators Alphabet in F# &amp; Silverlight &ndash; Part 1

    - by MarkPearl
    So I have been delving into F# more and more and thought the best way to learn the language is to write something useful. I have been meaning to get some more Silverlight knowledge (up to now I have mainly been doing WPF) so I came up with a really simple project that I can actually use at work. Simply put – I often get support calls from clients wanting new activation codes. One of our main app’s was written in VB6 and had its own “security” where it would require about a 45 character sequence for it to be activated. The catch being that each time you reopen the program it would require a different character sequence, which meant that when we activate clients systems we have to do it live! This involves us either referring them to a website, or reading the characters to them over the phone and since nobody in the office knows the IROA off by heart we would come up with some interesting words to represent characters… 9 times out of 10 the client would type in the wrong character and we would have to start all over again… with this app I am hoping to reduce the errors of reading characters over the phone by treating it like a ham radio. My “Silverlight” application will allow for the user to input a series of characters and the system will then generate the equivalent IROA words… very basic stuff e.g. Character Input – abc Words Generated – Alpha Bravo Charlie After listening to Anders Hejlsberg on Dot Net Rocks Show 541 he mentioned that he felt many applications could make use of F# but in an almost silo basis – meaning that you would write modules that leant themselves to Functional Programming in F# and then incorporate it into a solution where the front end may be in C# or where you would have some other sort of glue. I buy into this kind of approach, so in this project I will use F# to do my very intensive “Business Logic” and will use Silverlight/C# to do the front end. F# Business Layer I am no expert at this, so I am sure to get some feedback on way I could improve my algorithm. My approach was really simple. I would need a function that would convert a single character to a string – i.e. ‘A’ –> “Alpha” and then I would need a function that would take a string of characters, convert them into a sequence of characters, and then apply my converter to return a sequence of words… make sense? Lets start with the CharToString function let CharToString (element:char) = match element.ToString().ToLower() with | "1" -> "1" | "5" -> "5" | "9" -> "9" | "2" -> "2" | "6" -> "6" | "0" -> "0" | "3" -> "3" | "7" -> "7" | "4" -> "4" | "8" -> "8" | "a" -> "Alpha" | "b" -> "Bravo" | "c" -> "Charlie" | "d" -> "Delta" | "e" -> "Echo" | "f" -> "Foxtrot" | "g" -> "Golf" | "h" -> "Hotel" | "i" -> "India" | "j" -> "Juliet" | "k" -> "Kilo" | "l" -> "Lima" | "m" -> "Mike" | "n" -> "November" | "o" -> "Oscar" | "p" -> "Papa" | "q" -> "Quebec" | "r" -> "Romeo" | "s" -> "Sierra" | "t" -> "Tango" | "u" -> "Uniform" | "v" -> "Victor" | "w" -> "Whiskey" | "x" -> "XRay" | "y" -> "Yankee" | "z" -> "Zulu" | element -> "Unknown" Quite simple, an element is passed in, this element is them converted to a lowercase single character string and then matched up with the equivalent word. If by some chance a character is not recognized, “Unknown” will be returned… I know need a function that can take a string and can parse each character of the string and generate a new sequence with the converted words… let ConvertCharsToStrings (s:string) = s |> Seq.toArray |> Seq.map(fun elem -> CharToString(elem)) Here… the Seq.toArray converts the string to a sequence of characters. I then searched for some way to parse through every element in the sequence. Originally I tried Seq.iter, but I think my understanding of what iter does was incorrect. Eventually I found Seq.map, which applies a function to every element in a sequence and then creates a new collection with the adjusted processed element. It turned out to be exactly what I needed… To test that everything worked I created one more function that parsed through every element in a sequence and printed it. AT this point I realized the the Seq.iter would be ideal for this… So my testing code is below… let PrintStrings items = items |> Seq.iter(fun x -> Console.Write(x.ToString() + " ")) let newSeq = ConvertCharsToStrings("acdefg123") PrintStrings newSeq Console.ReadLine()   Pretty basic stuff I guess… I hope my approach was right? In Part 2 I will look into doing a simple Silverlight Frontend, referencing the projects together and deploying….

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  • International Radio Operators Alphabet in F# &amp; Silverlight &ndash; Part 2

    - by MarkPearl
    So the brunt of my my very complex F# code has been done. Now it’s just putting the Silverlight stuff in. The first thing I did was add a new project to my solution. I gave it a name and VS2010 did the rest of the magic in creating the .Web project etc. In this instance because I want to take the MVVM approach and make use of commanding I have decided to make the frontend a Silverlight4 project. I now need move my F# code into a proper Silverlight Library. Warning – when you create the Silverlight Library VS2010 will ask you whether you want it to be based on Silverlight3 or Silverlight4. I originally went for Silverlight4 only to discover when I tried to compile my solution that I was given an error… Error 12 F# runtime for Silverlight version v4.0 is not installed. Please go to http://go.microsoft.com/fwlink/?LinkId=177463 to download and install matching.. After asking around I discovered that the Silverlight4 F# runtime is not available yet. No problem, the suggestion was to change the F# Silverlight Library to a Silverlight3 project however when going to the properties of the project file – even though I changed it to Silverlight3, VS2010 did not like it and kept reverting it to a Silverlight4 project. After a few minutes of scratching my head I simply deleted Silverlight4 F# Library project and created a new F# Silverlight Library project in Silverlight3 and VS2010 was happy. Now that the project structure is set up, rest is fairly simple. You need to add the Silverlight Library as a reference to the C# Silverlight Front End. Then setup your views, since I was following the MVVM pattern I made a Views & ViewModel folder and set up the relevant View and ViewModels. The MainPageViewModel file looks as follows using System; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Ink; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; using System.Collections.ObjectModel; namespace IROAFrontEnd.ViewModels { public class MainPageViewModel : ViewModelBase { private string _iroaString; private string _inputCharacters; public string InputCharacters { get { return _inputCharacters; } set { if (_inputCharacters != value) { _inputCharacters = value; OnPropertyChanged("InputCharacters"); } } } public string IROAString { get { return _iroaString; } set { if (_iroaString != value) { _iroaString = value; OnPropertyChanged("IROAString"); } } } public ICommand MySpecialCommand { get { return new MyCommand(this); } } public class MyCommand : ICommand { readonly MainPageViewModel _myViewModel; public MyCommand(MainPageViewModel myViewModel) { _myViewModel = myViewModel; } public event EventHandler CanExecuteChanged; public bool CanExecute(object parameter) { return true; } public void Execute(object parameter) { var result = ModuleMain.ConvertCharsToStrings(_myViewModel.InputCharacters); var newString = ""; foreach (var Item in result) { newString += Item + " "; } _myViewModel.IROAString = newString.Trim(); } } } } One of the features I like in Silverlight4 is the new commanding. You will notice in my I have put the code under the command execute to reference to my F# module. At the moment this could be cleaned up even more, but will suffice for now.. public void Execute(object parameter) { var result = ModuleMain.ConvertCharsToStrings(_myViewModel.InputCharacters); var newString = ""; foreach (var Item in result) { newString += Item + " "; } _myViewModel.IROAString = newString.Trim(); } I then needed to set the view up. If we have a look at the MainPageView.xaml the xaml code will look like the following…. Nothing to fancy, but battleship grey for now… take careful note of the binding of the command in the button to MySpecialCommand which was created in the ViewModel. <UserControl x:Class="IROAFrontEnd.Views.MainPageView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400"> <Grid x:Name="LayoutRoot" Background="White"> <Grid.RowDefinitions> <RowDefinition/> <RowDefinition/> <RowDefinition/> </Grid.RowDefinitions> <TextBox Grid.Row="0" Text="{Binding InputCharacters, Mode=TwoWay}"/> <Button Grid.Row="1" Command="{Binding MySpecialCommand}"> <TextBlock Text="Generate"/> </Button> <TextBlock Grid.Row="2" Text="{Binding IROAString}"/> </Grid> </UserControl> Finally in the App.xaml.cs file we need to set the View and link it to the ViewModel. private void Application_Startup(object sender, StartupEventArgs e) { var myView = new MainPageView(); var myViewModel = new MainPageViewModel(); myView.DataContext = myViewModel; this.RootVisual = myView; }   Once this is done – hey presto – it worked. I typed in some “Test Input” and clicked the generate button and the correct Radio Operators Alphabet was generated. And that’s the end of my first very basic F# Silverlight application.

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  • Career guidance/advice for Junior-level Software Engineer [closed]

    - by John Do
    I have quite a few questions on my mind, so please bare with me. Please don't feel obligated to answer all of them, any as you choose will do. I'd appreciate if you could share some insight on any of these. Before I begin, some context: I currently have almost two years of professional experience as a Software Engineer, mainly developing software in Java. At this point, I feel that I have reached the peak in my career growth at the current company I am at and therefore I am looking for a new job, ideally again, as a Software Engineer. I have been interviewing for the past few months casually but have not had luck with companies I have a passion for. So, in no particular order - 1) In general, what are your thoughts on having graduate degrees in CS / Software Engineering. How much does it influence a salary increase, and do you think it's beneficial when working on real-world problems? I get the sense that a graduate degree in the field is trivial unless you really have a passion for research. 2) In general, in professional practice, how often had you have to write your own data structures and "complex" algorithms from scratch? In my own work, I have found myself relying mainly on third-party frameworks and the Java standard library to implement solutions as per business requirements. What are your thoughts on this? 3) In terms of resume, I feel the most ambivalent here. I want to be able to "blemish" my resume to a certain extent so that it stands out from others', but at the same time I do not want to over-exagerate my abilities. How do you strike a balance here? For example: I say that I am proficient in Java with data structures and algorithms. This is obviously a subjective and relative statement. I've taken the classes in my undergrad, and I've applied it in my work experience. What I feel as "prociency" can be seen as junior-level to others. How do you know what to say? Most of the time, recruiters (with no technical background) will be looking for keywords that stand out. This leads me to my next question (4). 4) Just from interviewing for the past few months (and getting plenty of rejections), I've come to realize that I may not be as proficient in data structures and algorithms as I thought I was. Do you think it's a good idea to remove the "proficient in java/data structure and algorithms"? I feel that being too hoenst on the resume will impede me from scoring opportunities to even have an interview with top-notch companies. What are your thoughts? 5) What is the absolute "must-have" knowledge going into a technical interview? I've been practicing several algorithmic and data sturcture problems now, and I feel that my abilities to solve arbitrary problems efficiently has not gotten significantly better. Do you think these abilities are something innate - it's either you have in you, or you don't? How can you teach yourself to learn, if you will? 6) How easy is it to go from industry/function to the next? I work mainly with backend technologies and I'm now interested in working with the frontend, i.e javascript,jquery,php or even mobile development. In your own experience, how did you not get pidgeon holed in your career? I feel that the choices you make now ultimately decide your future. As cliche as it sounds, I think it may be true. Here's what I mean: you've worked mainly as a backend engineer, people are interested in you doing the same thing since you've already accumulated experience in that function. How do get experience in a new function if people won't accept you because you don't already have it? It's a catch 22, you see... Are side projects the only real way to help you move from one function to another that you're truly interested in? For example: I could start writing my own mobile applications, even though I've worked mainly on the backend. Thanks so much for the long read. As a relatively new engineer to the real world, I am very humble and would like those who are experienced to shed some light. Thank you so much.

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  • YouTube Scalability Lessons

    - by Bertrand Matthelié
    @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Calibri"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }h2 { margin: 12pt 0cm 3pt; page-break-after: avoid; font-size: 14pt; font-family: "Times New Roman"; font-style: italic; }a:link, span.MsoHyperlink { color: blue; text-decoration: underline; }a:visited, span.MsoHyperlinkFollowed { color: purple; text-decoration: underline; }span.Heading2Char { font-family: Calibri; font-weight: bold; font-style: italic; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Very interesting blog post by Todd Hoff at highscalability.com presenting “7 Years of YouTube Scalability Lessons in 30 min” based on a presentation from Mike Solomon, one of the original engineers at YouTube: …. The key takeaway away of the talk for me was doing a lot with really simple tools. While many teams are moving on to more complex ecosystems, YouTube really does keep it simple. They program primarily in Python, use MySQL as their database, they’ve stuck with Apache, and even new features for such a massive site start as a very simple Python program. That doesn’t mean YouTube doesn’t do cool stuff, they do, but what makes everything work together is more a philosophy or a way of doing things than technological hocus pocus. What made YouTube into one of the world’s largest websites? Read on and see... Stats @font-face { font-family: "Arial"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } 4 billion Views a day 60 hours of video is uploaded every minute 350+ million devices are YouTube enabled Revenue double in 2010 The number of videos has gone up 9 orders of magnitude and the number of developers has only gone up two orders of magnitude. 1 million lines of Python code Stack @font-face { font-family: "Arial"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } Python - most of the lines of code for YouTube are still in Python. Everytime you watch a YouTube video you are executing a bunch of Python code. Apache - when you think you need to get rid of it, you don’t. Apache is a real rockstar technology at YouTube because they keep it simple. Every request goes through Apache. Linux - the benefit of Linux is there’s always a way to get in and see how your system is behaving. No matter how bad your app is behaving, you can take a look at it with Linux tools like strace and tcpdump. MySQL - is used a lot. When you watch a video you are getting data from MySQL. Sometime it’s used a relational database or a blob store. It’s about tuning and making choices about how you organize your data. Vitess- a  new project released by YouTube, written in Go, it’s a frontend to MySQL. It does a lot of optimization on the fly, it rewrites queries and acts as a proxy. Currently it serves every YouTube database request. It’s RPC based. Zookeeper - a distributed lock server. It’s used for configuration. Really interesting piece of technology. Hard to use correctly so read the manual Wiseguy - a CGI servlet container. Spitfire - a templating system. It has an abstract syntax tree that let’s them do transformations to make things go faster. Serialization formats - no matter which one you use, they are all expensive. Measure. Don’t use pickle. Not a good choice. Found protocol buffers slow. They wrote their own BSON implementation, which is 10-15 time faster than the one you can download. ...Contiues. Read the blog Watch the video

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