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  • Integrating Amazon EC2 in Java via NetBeans IDE

    - by Geertjan
    Next, having looked at Amazon Associates services and Amazon S3, let's take a look at Amazon EC2, the elastic compute cloud which provides remote computing services. I started by launching an instance of Ubuntu Server 14.04 on Amazon EC2, which looks a bit like this in the on-line AWS Management Console, though I whitened out most of the details: Now that I have at least one running instance available on Amazon EC2, it makes sense to use the services that are integrated into NetBeans IDE:  I created a new application with one class, named "AmazonEC2Demo". Then I dragged the "describeInstances" service that you see above, with the mouse, into the class. Then the IDE automatically created all the other files you see below, i.e., 4 Java classes and one properties file: In the properties file, register the access ID and secret keys. These are read by the other generated Java classes. Signing and authentication are done automatically by the code that is generated, i.e., there's nothing generic you need to do and you can immediately begin working on your domain-specific code. Finally, you're now able to rewrite the code in "AmazonEC2Demo" to connect to Amazon EC2 and obtain information about your running instance: public class AmazonEC2Demo { public static void main(String[] args) { String instanceId1 = "i-something"; RestResponse result; try { result = AmazonEC2Service.describeInstances(instanceId1); System.out.println(result.getDataAsString()); } catch (IOException ex) { Logger.getLogger(AmazonEC2Demo.class.getName()).log(Level.SEVERE, null, ex); } } } From the above, you'll receive a chunk of XML with data about the running instance, it's name, status, dates, etc. In other words, you're now ready to integrate Amazon EC2 features directly into the applications you're writing, without very much work to get started. Within about 5 minutes, you're working on your business logic, rather than on the generic code that anyone needs when integrating with Amazon EC2.

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  • Nodejs removing event listeners [migrated]

    - by JeffH
    Looking to get some help. I'm new to Nodejs and wondering if it is possible, to remove this custom event emitter. Most of this code comes from the Hand on nodejs by Pedro Teixeira. My function at the bottom is attempting to remove the custom event emitter you setup in the book. var util = require('util'); var EventEmitter = require('events').EventEmitter; // Pseudo-class named ticker that will self emit every 1 second. var Ticker = function() { var self = this; setInterval(function() { self.emit('tick'); }, 1000); }; // Bind the new EventEmitter to the sudo class. util.inherits(Ticker, EventEmitter); // call and instance of the ticker class to get the first // event started. Then let the event emitter run the infinante loop. var ticker = new Ticker(); ticker.on('tick', function() { console.log('Tick'); }); (function tock() { setInterval(function() { console.log('Tock'); EventEmitter.removeListener('Ticker',function() { console.log("Clocks Dead!"); }); }, 5000); })();

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  • Changing the Default Install Location of an MSI

    - by PSteele
    A few months ago, I had to tweak an MSI installer.  It was installing into a specific directory (named the same as the application) underneath Program Files.  Since the location of Program Files can change from machine to machine, the MSI has a special token you can use for Program Files (as well as for the application name).  So the current value for “DefaultLocation” of the Application Folder was: [ProgramFilesFolder]\[ProductName] During installation, these tokens would be replaced by the actual location based on the current machine. I needed to change this to a specific folder underneath the users My Documents directory.  I poked around the help file and I could not find where these special tokens (like “[ProgramFilesFolder]”) were defined.  Obviously, there must be some specific set of values that are available and I’m sure My Documents is one of them. I finally found them documented so I’m posting the link here.  Hopefully, it will help someone else out.  Not sure where I found this link… System Folder Properties For me, it was as easy as changing the DefaultLocation to: [PersonalFolder]\MyToolName\Application Technorati Tags: .NET,MSI

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  • Tracking Protection List in IE9

    - by Emanuele Bartolesi
    To protect the privacy when I surf over the internet, I use AdBlockPlus add-in for Firefox. But when I use Internet Explorer 9, this add-in don’t work. Internet Explorer 9 (and I hope Internet Explorer 10) has built in feature to add a TPL. There is a javascript function to call named msAddTrackingProtectionList. This function has two parameter: the first one is the link of TPL and the second one is the Title of TPL. To do this is very easy. Add this simple javascript function on your website or in a blank html page. <a href="javascript:window.external.msAddTrackingProtectionList('http://easylist-msie.adblockplus.org/easyprivacy.tpl', 'EasyList Privacy')">EasyPrivacy TPL</a> The effect is below: EasyPrivacy TPL After click appears a confirmation prompt. For security reason this javascript function can only be called from a user interaction: buttons, links, forms. For more information about msAddTrackingProtectionList function  go to Msdn Library. For more information about EasyList go to Easy List TPL.

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  • How to start Sharepoint Development - Resources wanted [closed]

    - by user1249641
    I'm a apprentice for software development here in good ol' Germany and I've been doing fairly well with c#, asp.net mvc, entity framework and LINQ so far. My superiors want me to focus solely on our intranet development and Sharepoint development. They don't provide me with any resources to start. No books, no co-workers with actual webpart-dev-experience, seminars and the likes. There for it's do it on your own or die. I bought a book and started working through it on my virtual machine messing with the infrastructure and everything i can get a grip on. My main problem however stays the actual development. I have managed to write 2 webparts which can be used as a rudimentary ticket system(using WSP Builder and SP2007). But there it stops. Are there any comprehensive step by step tutorials or blogs out there, like the asp.net tutorials on www.asp.net which take you by the hand go over each step with you? Starting with the basic classes, going over custom css implementation, Jquery/Javascript ajax and async calls? No matter how trivial, I appreciate every help and hint you can give.

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  • Information I need to know as a Java Developer [on hold]

    - by Woy
    I'm a java developer. I'm trying to get more knowledge to become a better programmer. I've listed a number of technologies to learn. Instead of what I've listed, what technologies would you suggest to learn as well for a Junior Java Developer? I realize, there's a lot of things to study. Java: - how a garbage collector works - resource management - network programming - TCP/IP HTTP - transactions, - consistency: interfaces, classes collections, hash codes, algorithms, comp. complexity concurrent programming: synchronizing, semafores steam management metability: thread-safety byte code manipulations, reflections, Aspect-Oriented Programming as base to understand frameworks such as Spring etc. Web stack: servlets, filters, socket programming Libraries: JDK, GWT, Apache Commons, Joda-Time, Dependency Injections: Spring, Nano Tools: IDE: very good knowledge - debugger - profiler - web analyzers: Wireshark, firebugs - unit testing SQL/Databases: Basics SELECTing columns from a table Aggregates Part 1: COUNT, SUM, MAX/MIN Aggregates Part 2: DISTINCT, GROUP BY, HAVING + Intermediate JOINs, ANSI-89 and ANSI-92 syntax + UNION vs UNION ALL x NULL handling: COALESCE & Native NULL handling Subqueries: IN, EXISTS, and inline views Subqueries: Correlated ITH syntax: Subquery Factoring/CTE Views Advanced Topics Functions, Stored Procedures, Packages Pivoting data: CASE & PIVOT syntax Hierarchical Queries Cursors: Implicit and Explicit Triggers Dynamic SQL Materialized Views Query Optimization: Indexes Query Optimization: Explain Plans Query Optimization: Profiling Data Modelling: Normal Forms, 1 through 3 Data Modelling: Primary & Foreign Keys Data Modelling: Table Constraints Data Modelling: Link/Corrollary Tables Full Text Searching XML Isolation Levels Entity Relationship Diagrams (ERDs), Logical and Physical Transactions: COMMIT, ROLLBACK, Error Handling

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  • pointers to member functions in an event dispatcher

    - by derivative
    For the past few days I've been trying to come up with a robust event handling system for the game (using a component based entity system, C++, OpenGL) I've been toying with. class EventDispatcher { typedef void (*CallbackFunction)(Event* event); typedef std::unordered_map<TypeInfo, std::list<CallbackFunction>, hash_TypeInfo > TypeCallbacksMap; EventQueue* global_queue_; TypeCallbacksMap callbacks_; ... } global_queue_ is a pointer to a wrapper EventQueue of std::queue<Event*> where Event is a pure virtual class. For every type of event I want to handle, I create a new derived class of Event, e.g. SetPositionEvent. TypeInfo is a wrapper on type_info. When I initialize my data, I bind functions to events in an unordered_map using TypeInfo(typeid(Event)) as the key that corresponds to a std::list of function pointers. When an event is dispatched, I iterate over the list calling the functions on that event. Those functions then static_cast the event pointer to the actual event type, so the event dispatcher needs to know very little. The actual functions that are being bound are functions for my component managers. For instance, SetPositionEvent would be handled by void PositionManager::HandleSetPositionEvent(Event* event) { SetPositionEvent* s_p_event = static_cast<SetPositionEvent*>(event); ... } The problem I'm running into is that to store a pointer to this function, it has to be static (or so everything leads me to believe.) In a perfect world, I want to store pointers member functions of a component manager that is defined in a script or whatever. It looks like I can store the instance of the component manager as well, but the typedef for this function is no longer simple and I can't find an example of how to do it. Is there a way to store a pointer to a member function of a class (along with a class instance, or, I guess a pointer to a class instance)? Is there an easier way to address this problem?

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  • I don't understand how TDD helps me get a good design if I need a design to start testing it

    - by Michael Stum
    I'm trying to wrap my head around TDD, specifically the development part. I've looked at some books, but the ones I found mainly tackle the testing part - the History of NUnit, why testing is good, Red/Green/Refactor and how to create a String Calculator. Good stuff, but that's "just" Unit Testing, not TDD. Specifically, I don't understand how TDD helps me get a good design if I need a Design to start testing it. To illustrate, imagine these 3 requirements: A catalog needs to have a list of products The catalog should remember which products a user viewed Users should be able to search for a product At this points, many books pull a magic rabbit out of a hat and just dive into "Testing the ProductService", but they don't explain how they came to the conclusion that there is a ProductService in the first place. That is the "Development" part in TDD that I'm trying to understand. There needs to be an existing design, but stuff outside of entity-services (that is: There is a Product, so there should be a ProductService) is nowhere to be found (e.g., the second requirement requires me to have some concept of a User, but where would I put the functionality to remind? And is Search a feature of the ProductService or a separate SearchService? How would I know which I should choose?) According to SOLID, I would need a UserService, but if I design a system without TDD, I might end up with a whole bunch of Single-Method Services. Isn't TDD intended to make me discover my design in the first place? I'm a .net developer, but Java resources would also work. I feel that there doesn't seem to be a real sample application or book that deals with a real line of business application. Can someone provide a clear example that illustrates the process of creating a design using TDD?

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  • What kind of permission is this? (Groups+Roles)

    - by Jorge
    I'm starting to need an access control for roles in my app. I don't know much of this, but I understand how vBulletin works: I create groups, then give permissions to groups. I think that what I need is the Role Bases Access Control (RBAC) , but i'm not sure, because I need groups to give permissions instead of single users (Maybe it's not that complicated to achieve). Example of what I'm thinking: Given a post: Editor's Group has permission to view it before it's published. Editor's Group has permission to edit its content. Public Group (Default) has not permission to view it before it's published. Admin Group has permission to delete the post. So basically I wan't orientation about if RBAC is what I need. And also, how would it be good to store group membership in a user, for example, would be good to have: ID NAME PASSWORD GROUPS (1, MyName, MyPassword, 1/2/3/4/5) and explode it via PHP or one registry for every Group membership in a table named permissions, example: USERID, USERGROUP values (1, 1), (1, 2) Maybe should be the second way because of the formal norms but I didn't study yet Databases 1 at college.

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  • No sound Ubuntu 12.04 through HDMI

    - by MikeMan
    Specs: Asus G73JH i7/720; ATI Mobility 5870 I have read through a lot of threads on getting HDMI sound to work and non of them have fixed my issue. Granted I am very new to Linux and know only the GUI aspect of what it does from finding similarities that Windows 7 has. I would like to become a Linux Power User and I figured this would be a good step to get started. I was able to successfully install my graphics driver and it shows in use. I connect the HDMI to my HD TV and I get no sound. I don't care about auto switch for sound, that would be great but not necessary. I just want my sound to work through the HDMI. What I have tried: Changed GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" to GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.audio=1" pact set-card-profile 0 output:hdmi-surround Failure: no such entity Sound Settings: Right-click Sound indicator ? Sound Settings ? Output Tab, and set Digital Output (S/PDIF) Built in Audio Speakers Built in Audio I only get 2 settings. If I right-click the area below those 2 in the "play sound through" box, I get no "show hidden devices". I am also doing all this with the HDMI connected to eliminate any possibility for error.

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  • How to Keep SEO Score from Dropping with Duplicate Content

    - by joeh0717
    I'm hoping that someone has a solution for what I'm trying to accomplish. I'm working on a travel agency web site and there's a "Overview" section for each cruise line. These overviews are located on the index page for each cruise line. Here's my issue: The company is creating a search engine that includes details on each cruise line. Their write-ups on each cruise line are great, so I'd like to include the overview they created for each cruise line, rather than having to create all new ones. However, I don't want duplicating their content to negatively affect the SEO scores of the pages they originally put this content on. It's gong to duplicate, since each page that's dynamically generated by their search engine is going to include a section about the cruise line (where I'd want to place the overview). Question: Is there any way that I can include these overviews (ideally, copying the exact HTML that they've already implemented) without the search engines indexing those particular code sections? I'd want the rest of the search result pages to be indexed...just not the section of each page that contains this duplicate code. I saw something about using a span class named robots-nocontent in Yahoo (not sure if this also applies to Bing) and googleon / googleoff tags in Google. Is this the best solution? I'm open to any suggestions, thanks!

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  • Are super methods in JavaScript limited to functional inheritance, as per Crockford's book?

    - by kindohm
    In Douglas Crockford's "JavaScript: The Good Parts", he walks through three types of inheritance: classical, prototypal, and functional. In the part on functional inheritance he writes: "The functional pattern also gives us a way to deal with super methods." He then goes on to implement a method named "superior" on all Objects. However, in the way he uses the superior method, it just looks like he is copying the method on the super object for later use: // crockford's code: var coolcat = function(spec) { var that = cat(spec), super_get_name = that.superior('get_name'); that.get_name = function (n) { return 'like ' + super_get_name() + ' baby'; }; return that; }; The original get_name method is copied to super_get_name. I don't get what's so special about functional inheritance that makes this possible. Can't you do this with classical or prototypal inheritance? What's the difference between the code above and the code below: var CoolCat = function(name) { this.name = name; } CoolCat.prototype = new Cat(); CoolCat.prototype.super_get_name = CoolCat.prototype.get_name; CoolCat.prototype.get_name = function (n) { return 'like ' + this.super_get_name() + ' baby'; }; Doesn't this second example provide access to "super methods" too?

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  • Trouble with collision detection in XNA?

    - by Lewis Wilcock
    I'm trying to loop through an list of enemies (enemyList) and then any that have intersected the rectangle belonging to the box object (Which doesn't move), declare there IsAlive bool as false. Then another part of the code removes any enemies that have the IsAlive bool as false. The problem im having is getting access to the variable that holds the Rectangle (named boundingBox) of the enemy. When this is in a foreach loop it works fine, as the enemy class is declared within the foreach. However, there are issues in using the foreach as it removes more than one of the enemies at once (Usually at positions 0 and 2, 1 and 3, etc...). I was wondering the best way to declare the enemy class, without it actually creating new instances of the class? Heres the code I currently have: if (keyboardState.IsKeyDown(Keys.Q) && oldKeyState.IsKeyUp(Keys.Q)) { enemyList.Add(new enemy(textureList.ElementAt(randText), new Vector2(250, 250), graphics)); } //foreach (enemy enemy in enemyList) //{ for (int i = 0; i < enemyList.Count; i++) { if (***enemy.boundingBox***.Intersects(theDefence.boxRectangle)) { enemyList[i].IsDead = true; i++; } } //} for(int j = enemyList.Count - 1; j >= 0; j--) { if(enemyList[j].IsDead) enemyList.RemoveAt(j); } (The enemy.boundingBox is the variables I can't get access too). This is a complete copy of the code (Zipped) If it helps: https://www.dropbox.com/s/ih52k4e21g98j3k/Collision%20tests.rar I managed to find the issue. Changed enemy.boundingBox to enemyList[i].boundingBox. Collision works now! Thanks for any help!

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  • Change AccountName/LoginName for a SharePoint User (SPUser)

    - by Rohit Gupta
    Consider the following: We have an account named MYDOMAIN\eholz. This accounts Active Directory Login Name changes to MYDOMAIN\eburrell Now this user was a active user in a Sharepoint 2010 team Site, and had a userProfile using the Account name MYDOMAIN\eholz. Since the AD LoginName changed to eburrell hence we need to update the Sharepoint User (SPUser object) as well update the userprofile to reflect the new account name. To update the Sharepoint User LoginName we can run the following stsadm command on the Server: STSADM –o migrateuser –oldlogin MYDOMAIN\eholz –newlogin MYDOMAIN\eburrell –ignoresidhistory However to update the Sharepoint 2010 UserProfile, i first tried running a Incremental/Full Synchronization using the User Profile Synchronization service… this did not work. To enable me to update the AccountName field (which is a read only field) of the UserProfile, I had to first delete the User Profile for MYDOMAIN\eholz and then run a FULL Synchronization using the User Profile Synchronization service which synchronizes the Sharepoint User Profiles with the AD profiles. Update: if you just run the STSADM –o migrateuser command… the profile also gets updated automatically. so all you need is to run the stsadm –o migrate user command and you dont need to delete and recreate the User Profile

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  • MySQL Connector/Net 6.6 GA has been released

    - by fernando
    MySQL Connector/Net 6.6, a new version of the all-managed .NET driver for MySQL has been released.  This is the GA intended to introduce users to the new features in the release.  This release is feature complete. It is recommended for use in production environments. It is appropriate for use with MySQL server versions 5.0-5.6 It is now available in source and binary form from http://dev.mysql.com/downloads/connector/net/#downloads and mirror sites (note that not all mirror sites may be up to date at this point-if you can't find this version on some mirror, please try again later or choose another download site.) The 6.6 version of MySQL Connector/Net brings the following new features:   * Stored routine debugging   * Entity Framework 4.3 Code First support   * Pluggable authentication (now third parties can plug new authentications mechanisms into the driver).   * Full Visual Studio 2012 support: everything from Server Explorer to Intellisense&   the Stored Routine debugger. The release is available to download athttp://dev.mysql.com/downloads/connector/net/6.6.html Documentation ------------------------------------- You can view current Connector/Net documentation at http://dev.mysql.com/doc/refman/5.5/en/connector-net.html For specific topics: Stored Routine Debugger:http://dev.mysql.com/doc/refman/5.5/en/connector-net-visual-studio-debugger.html Authentication plugin:http://dev.mysql.com/doc/refman/5.5/en/connector-net-programming-authentication-user-plugin.html You can find our team blog at http://blogs.oracle.com/MySQLOnWindows. You can also post questions on our forums at http://forums.mysql.com/. Enjoy and thanks for the support! 

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  • What makes you look like a bad developer (ie a hacker) [on hold]

    - by user134583
    This comes from a lot of people about me, so I have to look at myself. So I would wonder what make one a bad developer (ie a hacker). These are a few things about me I used IDE intensively, all features, you name it: auto-completion, refactoring, quick fixes, open type, view hierarchy, API documentation, etcc When I deal with writing code for a project in domain I am not used to (I can't have fluency in this, this is new), I only have a very rough high level ideas. I don't use the standard modeling diagrams for early detail planning. Unorthodox diagrams that I invented when I need to draw the design in details. I don't use UML or similar, I find them not enough. I divide the sorts of diagram I drew into 3 types. Very high level diagrams which probably can be understood by almost anybody. Data entity diagram used for modeling data objects only (like ER diagrams and tree for inheritances and composition). Action diagrams for agents/classes and their interactions on data objects they contain. Constantly changing the interface (public methods) between interacting agents/classes if the need arises. I am more refrained when the interface and the module have matured Write initial concept code in a quick hackie way just so that the module works in the general cases so that I can play around with it. The module will be re-factored intensively after playing around so I could see more corner cases that I couldn't or (wouldn't want) anticipate before writing code. Using JUnit for integration-like test by using TestSuite class and ordering Unit test classes in the suite Using debugger almost anytime there is a problem instead of reading the code Constantly search on the internet for how to do some thing with some library that I haven't used a lot. So judgment, am I a bad developer? a hacker? Put in other words, to make sure this is not considered off-topic: - Is this bad practice to make your code too agile during incubating/prototyping phase of software development - Is it bad practice to use JUnit for integration testing, (I know there are other framework for integration testing, but those frameworks are for a specific products, not general)

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  • How to disguise a serverside mob as another?

    - by Shaun Wild
    I've been working a Minecraft sever mod and i want to be able to add a new entity to the server, but then make the server send the packets to the client, imitating another mob, for example.. Lets say say i have EntityPlayerNPC.class, what i want to do is have all of the packets that get sent to the client look like they are from that of another player which is on the player, therefore allowing me to add custom NPC's... Thinking about the theory i'm sure this can be done. I've tried looking around for where the packets are being sent from and whatnot, can anyone think up a solution? edit: i tried adding a new constructor to the Packet20NamedEntitySpawn class like so: public Packet20NamedEntitySpawn(String username, EntityLiving e){ this.entityId = 0; this.name = username; this.xPosition = MathHelper.floor_double(e.posX * 32.0D); this.yPosition = MathHelper.floor_double(e.posY * 32.0D); this.zPosition = MathHelper.floor_double(e.posZ * 32.0D); this.rotation = (byte)((int)(e.rotationYaw * 256.0F / 360.0F)); this.pitch = (byte)((int)(e.rotationPitch * 256.0F / 360.0F)); this.metadata = e.getDataWatcher(); } unfortunatley, that didn't work :(

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  • How to work with processes?

    - by Viesturs
    I have seen similar questions here, but I didn't get my answer. Maybe it's because I am new to all this and just don't understand. I want my app to work mostly as an indicator. And if user would start it again it would check if it is already running, if it is then give all the input data to that process and quit. So first I need to check if it is running. I saw the answer where you can make a file witch when the program starts and then check if it exists... But what if someone would delete it? Can't I just ask the OS if there is process named "myApp" or something? The next thing I don't really get is how to communicate with the process. How do I give it the input data and what is it going to do with it? Does it work just like starting a new app, through the main() method? I am trying to create this using Quickly. So it would be nice if you can give me some python examples or link to something like that.

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  • MVC 4 Authentication

    - by Aligned
    First: After searching for awhile to figure out what’s new/different with MVC 4 and forms authentication, this is the best article I've found on the subject: http://weblogs.asp.net/jgalloway/archive/2012/08/29/simplemembership-membership-providers-universal-providers-and-the-new-asp-net-4-5-web-forms-and-asp-net-mvc-4-templates.aspx Some quotes from the article: “The ASP.NET Web Pages team designed SimpleMembership to (wait for it) simplify the task of dealing with membership” "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)" “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:” “Universal Providers do not work with Simple Membership.” ~ this post (look for Bob.at.SBS’s answer) says Universal Providers is not needed for MVC 4 to work in Azure)   I've been trying to figure out the Forms Authentication in MVC4. It's different than the past approach (aspnet_regsql). If you do file new project -> MVC 4 -> internet application, you get a really nice template with the controller and model setup for you. However, the tables are different than using aspnet_regsql and the ASP.Net Configuration tool (WSAT) wasn’t connecting to the data I had (it was creating an App_Data/aspnet.mdf file, which I didn’t see right away). Points of Note The database tables are created in the SimpleMembershipInitializer class, when you first run your app using Entity Framework 5 migration functionality. The tables created are webpages_Membership, webpages_OAuthMembership, webpages_Roles, webpages_UsersInRoles, UserProfile. Web.config settings don’t seem to be needed.   Scott Hanselman on Universal Providers was also useful if not somewhat out dated. Universal Providers and SimpleMembership are not compatible. http://www.asp.net/web-pages/tutorials/security/16-adding-security-and-membership – walk-through

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  • Do there exist programming languages where a variable can truly know its own name?

    - by Job
    In PHP and Python one can iterate over the local variables and, if there is only once choice where the value matches, you could say that you know what the variable's name is, but this does not always work. Machine code does not have variable names. C compiles to assembly and does not have any native reflection capabilities, so it would not know it's name. (Edit: per Anton's answer the pre-processor can know the variable's name). Do there exist programming languages where a variable would know it's name? It gets tricky if you do something like b = a and b does not become a copy of a but a reference to the same place. EDIT: Why in the world would you want this? I can think of one example: error checking that can survive automatic refactoring. Consider this C# snippet: private void CheckEnumStr(string paramName, string paramValue) { if (paramName != "pony" && paramName != "horse") { string exceptionMessage = String.Format( "Unexpected value '{0}' of the parameter named '{1}'.", paramValue, paramName); throw new ArgumentException(exceptionMessage); } } ... CheckEnumStr("a", a); // Var 'a' does not know its name - this will not survive naive auto-refactoring There are other libraries provided by Microsoft and others that allow to check for errors (sorry the names have escaped me). I have seen one library which with the help of closures/lambdas can accomplish error checking that can survive refactoring, but it does not feel idiomatic. This would be one reason why I might want a language where a variable knows its name.

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  • How to structure reading of commands given at a(n interactive) CLI prompt?

    - by Anto
    Let's say I have a program called theprogram (the marketing team was on strike when the product was to be named). I start that program by typing, perhaps not surprisingly, the program name as a command into a command prompt. After that, I get into a loop (from the users standpoint, an interactive command-line prompt), where one command will be read from the user, and depending on what command was given, the program will execute some instructions. I have been doing something like the following (in C-like pseudocode): main_loop{ in=read_input(); if(in=="command 1") do_something(); else if(in=="command 2") do_something_else(); ... } (In a real program, I would probably encapsulate more things into different procedures, this is just an example.) This works well for a small amount of commands, but let's say you have 100, 1000 or even 10 000 of them (the manual would be huge!). It is clearly a bad idea to have 10 000 ifs and else ifs after each other, for instance, the program would be hard to read, hard to maintain, contain a lot of boilerplate code... Yeah, you don't want to do that, so what approach would you recommend me to use (I will probably never use 10 000 commands in a program, but the solution should, at least preferably, be able to scale to that kind of massive (?) problems. The solution doesn't have to allow for arguments to the commands)?

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  • decouple software components via nameconvention

    - by csteinmueller
    I'm currently evaluating alternatives to refactor a drivermanagement. In my multitier architecture I have Baseclass DAL.Device //my entity Interfaces BL.IDriver //handles the dataprocessing between application and device BL.IDriverCreator //creates an IDriver from a Device BL.IDriverFactory //handles the driver creation requests Every specialization of Device has a corresponding IDriver implementation and a corresponding IDriverCreator implementation. At the moment the mapping is fix via a type check within the business layer / DriverFactory. That means every new driver needs a) changing code within the DriverFactory and b) referencing the new IDriver implementation / assembly. On a customers point of view that means, every new driver, used or not, needs a complex revalidation of their hardware environment, because it's a critical process. My first inspiration was to use a caliburn micro like nameconvention see Caliburn.Micro: Xaml Made Easy BL.RestDriver BL.RestDriverCreator DAL.RestDevice After receiving the RestDevicewithin the IDriverFactory I can load all driver dlls via reflection and do a namesplitting/comparing (extracting the xx from xxDriverCreator and xxDevice) Another idea would be a custom attribute (which also leads to comparing strings). My question: is that a good approach above layer borders? If not, what would be a good approach?

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  • Using mod_rewrite for a Virtual Filesystem vs. Real Filesystem

    - by philtune
    I started working in a department that uses a CMS in which the entire "filesystem" is like this: create a named file or folder - this file is given a unique node (ex. 2345) as well as a default "filename" (ex. /WelcomeToOurProductsPage) and apply a template assign one or more aliases to the file for a URL redirect (ex. /home-page-products - can also be accessed by /home-page-products.aspx) A new Rewrite command is written on the .htaccess file for each and every alias Server accesses either /WelcomeToOurProductsPage or /home-page-products and redirects to something like /template.aspx?tmp=2&node=2345 (here I'm guessing what it does - I only have front-end access for now - but I have enough clues to strongly assume) Node 2345 grabs content stored in a SQL Db and applies it to the template. Note: There are no actual files being created on the filesystem. It's entirely virtual. This is probably a very common thing, but since I have never run across this kind of system before two months ago, I wanted to explain it in case it isn't common. I'm not a fan at all of ASP or closed-sourced systems, so it may be that this is common practice for ASP developers. My question, that has taken far too long to ask, is: what are the benefits of this kind of system, as opposed to creating an actual file hierarchy? Are there any drawbacks to having every single file server call redirected? To having the .htaccess file hold rewrite rules for every single alias?

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  • Creating a Predicate Builder extension method

    - by Rippo
    I have a Kendo UI Grid that I am currently allowing filtering on multiple columns. I am wondering if there is a an alternative approach removing the outer switch statement? Basically I want to able to create an extension method so I can filter on a IQueryable<T> and I want to drop the outer case statement so I don't have to switch column names. private static IQueryable<Contact> FilterContactList(FilterDescriptor filter, IQueryable<Contact> contactList) { switch (filter.Member) { case "Name": switch (filter.Operator) { case FilterOperator.StartsWith: contactList = contactList.Where(w => w.Firstname.StartsWith(filter.Value.ToString()) || w.Lastname.StartsWith(filter.Value.ToString()) || (w.Firstname + " " + w.Lastname).StartsWith(filter.Value.ToString())); break; case FilterOperator.Contains: contactList = contactList.Where(w => w.Firstname.Contains(filter.Value.ToString()) || w.Lastname.Contains(filter.Value.ToString()) || (w.Firstname + " " + w.Lastname).Contains( filter.Value.ToString())); break; case FilterOperator.IsEqualTo: contactList = contactList.Where(w => w.Firstname == filter.Value.ToString() || w.Lastname == filter.Value.ToString() || (w.Firstname + " " + w.Lastname) == filter.Value.ToString()); break; } break; case "Company": switch (filter.Operator) { case FilterOperator.StartsWith: contactList = contactList.Where(w => w.Company.StartsWith(filter.Value.ToString())); break; case FilterOperator.Contains: contactList = contactList.Where(w => w.Company.Contains(filter.Value.ToString())); break; case FilterOperator.IsEqualTo: contactList = contactList.Where(w => w.Company == filter.Value.ToString()); break; } break; } return contactList; } Some additional information, I am using NHibernate Linq. Also another problem is that the "Name" column on my grid is actually "Firstname" + " " + "LastName" on my contact entity. We can also assume that all filterable columns will be strings.

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  • How should I implement Transaction database EJB 3.0

    - by JamesBoyZ
    In the CustomerTransactions entity, I have the following field to record what the customer bought: @ManyToMany private List<Item> listOfItemsBought; When I think more about this field, there's a chance it may not work because merchants are allowed to change item's information (e.g. price, discount, etc...). Hence, this field will not be able to record what the customer actually bought when the transaction occurred. At the moment, I can only think of 2 ways to make it work. I will record the transaction details into a String field. I feel that this way would be messy if I need to extract some information about the transaction later on. Whenever the merchant changes an item's information, I will not update directly to that item's fields. Instead, I will create another new item with all the new information and keep the old item untouched. I feel that this way is better because I can easily extract information about the transaction later on. However, the bad side is that my Item table may contain a lot of rows. I'd be very grateful if someone could give me an advice on how I should tackle this problem. UPDATE: I'd like to add more information about the current design. public class Customer implements Serializable { @OneToMany private List<CustomerTransactions> listOfTransactions; } public class CustomerTransactions implements Serializable { @ManyToMany private List<Item> listOfItemsBought; } public class Merchant implements Serializable { @OneToMany private List<Item> listOfSellingItems; }

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