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• what differs a computer scientist/software engineer to regular people who learn programming language and APIs?

  - by Amumu

  In University, we learn and reinvent the wheel a lot to truly learn the programming concepts. For example, we may learn assembly language to understand, what happens inside the box, and how the system operates, when we execute our code. This helps understanding higher level concepts deeper. For example, memory management like in C is just an abstraction of manually managed memory contents and addresses. The problem is, when we're going to work, usually productivity is required more. I could program my own containers, or string class, or date/time (using POSIX with C system call) to do the job, but then, it would take much longer time to use existing STL or Boost library, which abstract all of those thing and very easy to use. This leads to an issue, that a regular person doesn't need to get through all the low level/under the hood stuffs, who learns only one programming language and using language-related APIs. These people may eventually compete with the mainstream graduates from computer science or software engineer and call themselves programmers. At first, I don't think it's valid to call them programmers. I used to think, a real programmer needs to understand the computer deeply (but not at the electronic level). But then I changed my mind. After all, they get the job done and satisfy all the test criteria (logic, performance, security...), and in business environment, who cares if you're an expert and understand how computer works or not. You may get behind the "amateurs" if you spend to much time learning about how things work inside. It is totally valid for those people to call themselves programmers. This makes me confuse. So, after all, programming should be considered an universal skill? Does programming language and concepts matter or the problems we solve matter? For example, many C/C++ vs Java and other high level language, one of the main reason is because C/C++ features performance, as well as accessing low level facility. One of the main reason (in my opinion), is coding in C/C++ seems complex, so people feel good about it (not trolling anyone, just my observation, and my experience as well. Try to google "C hacker syndrome"). While Java on the other hand, made for simplifying programming tasks to help developers concentrate on solving their problems. Based on Java rationale, if the programing language keeps evolve, one day everyone can map their logic directly with natural language. Everyone can program. On that day, maybe real programmers are mathematicians, who could perform most complex logic (including business logic and academic logic) without worrying about installing/configuring compiler, IDEs? What's our job as a computer scientist/software engineer? To solve computer specific problems or to solve problems in general? For example, take a look at this exame: http://cm.baylor.edu/ICPCWiki/attach/Problem%20Resources/2010WorldFinalProblemSet.pdf . The example requires only basic knowledge about the programming language, but focus more on problem solving with the language. In sum, what differs a computer scientist/software engineer to regular people who learn programming language and APIs? A mathematician can be considered a programmer, if he is good enough to use programming language to implement his formula. Can we programmer do this? Probably not for most of us, since we specialize about computer, not math. An electronic engineer, who learns how to use C to program for his devices, can be considered a programmer. If the programming languages keep being simplified, may one day the software engineers, who implements business logic and create softwares, be obsolete? (Not for computer scientist though, since many of the CS topics are scientific, and science won't change, but technology will).

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• Where to store front-end data for "object calculator"

  - by Justin Grahn

  I recently have completed a language library that acts as a giant filter for food items, and flows a bit like this :Products -> Recipes -> MenuItems -> Meals and finally, upon submission, creates an Order. I have also completed a database structure that stores all the pertinent information to each class, and seems to fit my needs. The issue I'm having is linking the two. I imagined all of the information being local to each instance of the product, where there exists one backend user who edits and manipulates data, and multiple front end users who select their Meal(s) to create an Order. Ideally, all of the front end users would have all of this information stored locally within the library, and would update the library on startup from a database. How should I go about storing the data so that I can load it into the library every time the user opens the application? Do I package a database onboard and just load and populate every time? The only method I can currently conceive of doing this, even if I only have 500 possible Product objects, would require me to foreach the list for every Product that I need to match to a Recipe and so on and so forth every time I relaunch the program, which seems like a lot of wasteful loading. Here is a general flow of my architecture: Products: public class Product : IPortionable { public Product(string n, uint pNumber = 0) { name = n; productNumber = pNumber; } public string name { get; set; } public uint productNumber { get; set; } } Recipes: public Recipe(string n, decimal yieldAmt, Volume.Unit unit) { name = n; yield = new Volume(yieldAmt, unit); yield.ConvertUnit(); } /// <summary> /// Creates a new ingredient object /// </summary> /// <param name="n">Name</param> /// <param name="yieldAmt">Recipe Yield</param> /// <param name="unit">Unit of Yield</param> public Recipe(string n, decimal yieldAmt, Weight.Unit unit) { name = n; yield = new Weight(yieldAmt, unit); } public Recipe(Recipe r) { name = r.name; yield = r.yield; ingredients = r.ingredients; } public string name { get; set; } public IMeasure yield; public Dictionary<IPortionable, IMeasure> ingredients = new Dictionary<IPortionable,IMeasure>(); MenuItems: public abstract class MenuItem : IScalable { public static string title = null; public string name { get; set; } public decimal maxPortionSize { get; set; } public decimal minPortionSize { get; set; } public Dictionary<IPortionable, IMeasure> ingredients = new Dictionary<IPortionable, IMeasure>(); and Meal: public class Meal { public Meal(int guests) { guestCount = guests; } public int guestCount { get; private set; } //TODO: Make a new MainCourse class that holds pasta and Entree public Dictionary<string, int> counts = new Dictionary<string, int>(){ {MainCourse.title, 0}, {Side.title , 0}, {Appetizer.title, 0} }; public List<MenuItem> items = new List<MenuItem>(); The Database just stores and links each of these basic names and amounts together usings ID's (RecipeID, ProductID and MenuItemID)

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• Handling Configuration Changes in Windows Azure Applications

  - by Your DisplayName here!

  While finalizing StarterSTS 1.5, I had a closer look at lifetime and configuration management in Windows Azure. (this is no new information – just some bits and pieces compiled at one single place – plus a bit of reality check) When dealing with lifetime management (and especially configuration changes), there are two mechanisms in Windows Azure – a RoleEntryPoint derived class and a couple of events on the RoleEnvironment class. You can find good documentation about RoleEntryPoint here. The RoleEnvironment class features two events that deal with configuration changes – Changing and Changed. Whenever a configuration change gets pushed out by the fabric controller (either changes in the settings section or the instance count of a role) the Changing event gets fired. The event handler receives an instance of the RoleEnvironmentChangingEventArgs type. This contains a collection of type RoleEnvironmentChange. This in turn is a base class for two other classes that detail the two types of possible configuration changes I mentioned above: RoleEnvironmentConfigurationSettingsChange (configuration settings) and RoleEnvironmentTopologyChange (instance count). The two respective classes contain information about which configuration setting and which role has been changed. Furthermore the Changing event can trigger a role recycle (aka reboot) by setting EventArgs.Cancel to true. So your typical job in the Changing event handler is to figure if your application can handle these configuration changes at runtime, or if you rather want a clean restart. Prior to the SDK 1.3 VS Templates – the following code was generated to reboot if any configuration settings have changed: private void RoleEnvironmentChanging(object sender, RoleEnvironmentChangingEventArgs e) {     // If a configuration setting is changing     if (e.Changes.Any(change => change is RoleEnvironmentConfigurationSettingChange))     {         // Set e.Cancel to true to restart this role instance         e.Cancel = true;     } } This is a little drastic as a default since most applications will work just fine with changed configuration – maybe that’s the reason this code has gone away in the 1.3 SDK templates (more). The Changed event gets fired after the configuration changes have been applied. Again the changes will get passed in just like in the Changing event. But from this point on RoleEnvironment.GetConfigurationSettingValue() will return the new values. You can still decide to recycle if some change was so drastic that you need a restart. You can use RoleEnvironment.RequestRecycle() for that (more). As a rule of thumb: When you always use GetConfigurationSettingValue to read from configuration (and there is no bigger state involved) – you typically don’t need to recycle. In the case of StarterSTS, I had to abstract away the physical configuration system and read the actual configuration (either from web.config or the Azure service configuration) at startup. I then cache the configuration settings in memory. This means I indeed need to take action when configuration changes – so in my case I simply clear the cache, and the new config values get read on the next access to my internal configuration object. No downtime – nice! Gotcha A very natural place to hook up the RoleEnvironment lifetime events is the RoleEntryPoint derived class. But with the move to the full IIS model in 1.3 – the RoleEntryPoint methods get executed in a different AppDomain (even in a different process) – see here.. You might no be able to call into your application code to e.g. clear a cache. Keep that in mind! In this case you need to handle these events from e.g. global.asax.

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• Design Pattern for building a Budget

  - by Scott

  So I've looked at the Builder Pattern, Abstract Interfaces, other design patterns, etc. - and I think I'm over thinking the simplicity behind what I'm trying to do, so I'm asking you guys for some help with either recommending a design pattern I should use, or an architecture style I'm not familiar with that fits my task. So I have one model that represents a Budget in my code. At a high level, it looks like this: public class Budget { public int Id { get; set; } public List<MonthlySummary> Months { get; set; } public float SavingsPriority { get; set; } public float DebtPriority { get; set; } public List<Savings> SavingsCollection { get; set; } public UserProjectionParameters UserProjectionParameters { get; set; } public List<Debt> DebtCollection { get; set; } public string Name { get; set; } public List<Expense> Expenses { get; set; } public List<Income> IncomeCollection { get; set; } public bool AutoSave { get; set; } public decimal AutoSaveAmount { get; set; } public FundType AutoSaveType { get; set; } public decimal TotalExcess { get; set; } public decimal AccountMinimum { get; set; } } To go into more detail about some of the properties here shouldn't be necessary, but if you have any questions about those I will fill more out for you guys. Now, I'm trying to create code that builds one of these things based on a set of BudgetBuildParameters that the user will create and supply. There are going to be multiple types of these parameters. For example, on the sites homepage, there will be an example section where you can quickly see what your numbers look like, so they would be a much simpler set of SampleBudgetBuildParameters then say after a user registers and wants to create a fully filled out Budget using much more information in the DebtBudgetBuildParameters. Now a lot of these builds are going to be using similar code for certain tasks, but might want to also check the status of a users DebtCollection when formulating a monthly spending report, where as a Budget that only focuses on savings might not want to. I'd like to reduce code duplication (obviously) as much as possible, but in my head, every way I can think to do this would require using a base BudgetBuilderFactory to return the correct builder to the caller, and then creating say a SimpleBudgetBuilder that inherits from a BudgetBuilder, and put all duplicate code in the BudgetBuilder, and let the SimpleBudgetBuilder handle it's own cases. Problem is, a lot of the unique cases are unique to 2/4 builders, so there will be duplicate code somewhere in there obviously if I did that. Can anyone think of a better way to either explain a solution to this that may or may not be similar to mine, or a completely different pattern or way of thinking here? I really appreciate it.

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• methods DSA_do_verify and SHA1 (OpenSSL library for Windows)

  - by Rei

  i am working on a program to authenticate an ENC signature file by using OpenSSL for windows, and specifically methods DSA_do_verify(...) and SHA1(...) hash algorithm, but is having problems as the result from DSA_do_verify is always 0 (invalid). I am using the signature file of test set 4B from the IHO S-63 Data Protection Scheme, and also the SA public key (downloadable from IHO) for verification. Below is my program, can anyone help to see where i have gone wrong as i have tried many ways but failed to get the verification to be valid, thanks.. The signature file from test set 4B // Signature part R: 3F14 52CD AEC5 05B6 241A 02C7 614A D149 E7D6 C408. // Signature part S: 44BB A3DB 8C46 8D11 B6DB 23BE 1A79 55E6 B083 7429. // Signature part R: 93F5 EF86 1FF6 BA6F 1C2B B9BB 7F36 0C80 2F9B 2414. // Signature part S: 4877 8130 12B4 50D8 3688 B52C 7A84 8E26 D442 8B6E. // BIG p C16C BAD3 4D47 5EC5 3966 95D6 94BC 8BC4 7E59 8E23 B5A9 D7C5 CEC8 2D65 B682 7D44 E953 7848 4730 C0BF F1F4 CB56 F47C 6E51 054B E892 00F3 0D43 DC4F EF96 24D4 665B. // BIG q B7B8 10B5 8C09 34F6 4287 8F36 0B96 D7CC 26B5 3E4D. // BIG g 4C53 C726 BDBF BBA6 549D 7E73 1939 C6C9 3A86 9A27 C5DB 17BA 3CAC 589D 7B3E 003F A735 F290 CFD0 7A3E F10F 3515 5F1A 2EF7 0335 AF7B 6A52 11A1 1035 18FB A44E 9718. // BIG y 15F8 A502 11C2 34BB DF19 B3CD 25D1 4413 F03D CF38 6FFC 7357 BCEE 59E4 EBFD B641 6726 5E5F 0682 47D4 B50B 3B86 7A85 FB4D 6E01 8329 A993 C36C FD9A BFB6 ED6D 29E0. dataServer_pkeyfile.txt (extracted from above) // BIG p C16C BAD3 4D47 5EC5 3966 95D6 94BC 8BC4 7E59 8E23 B5A9 D7C5 CEC8 2D65 B682 7D44 E953 7848 4730 C0BF F1F4 CB56 F47C 6E51 054B E892 00F3 0D43 DC4F EF96 24D4 665B. // BIG q B7B8 10B5 8C09 34F6 4287 8F36 0B96 D7CC 26B5 3E4D. // BIG g 4C53 C726 BDBF BBA6 549D 7E73 1939 C6C9 3A86 9A27 C5DB 17BA 3CAC 589D 7B3E 003F A735 F290 CFD0 7A3E F10F 3515 5F1A 2EF7 0335 AF7B 6A52 11A1 1035 18FB A44E 9718. // BIG y 15F8 A502 11C2 34BB DF19 B3CD 25D1 4413 F03D CF38 6FFC 7357 BCEE 59E4 EBFD B641 6726 5E5F 0682 47D4 B50B 3B86 7A85 FB4D 6E01 8329 A993 C36C FD9A BFB6 ED6D 29E0. Program abstract: QbyteArray pk_data; QFile pk_file("./dataServer_pkeyfile.txt"); if (pk_file.open(QIODevice::Text | QIODevice::ReadOnly)) { pk_data.append(pk_file.readAll()); } pk_file.close(); unsigned char ptr_sha_hashed[20]; unsigned char *ptr_pk_data = (unsigned char *)pk_data.data(); // openssl SHA1 hashing algorithm SHA1(ptr_pk_data, pk_data.length(), ptr_sha_hashed); DSA_SIG *dsasig = DSA_SIG_new(); char ptr_r[] = "93F5EF861FF6BA6F1C2BB9BB7F360C802F9B2414"; //from tset 4B char ptr_s[] = "4877813012B450D83688B52C7A848E26D4428B6E"; //from tset 4B if (BN_hex2bn(&dsasig->r, ptr_r) == 0) return 0; if (BN_hex2bn(&dsasig->s, ptr_s) == 0) return 0; DSA *dsakeys = DSA_new(); //the following values are from the SA public key char ptr_p[] = "FCA682CE8E12CABA26EFCCF7110E526DB078B05EDECBCD1EB4A208F3AE1617AE01F35B91A47E6DF63413C5E12ED0899BCD132ACD50D99151BDC43EE737592E17"; char ptr_q[] = "962EDDCC369CBA8EBB260EE6B6A126D9346E38C5"; char ptr_g[] = "678471B27A9CF44EE91A49C5147DB1A9AAF244F05A434D6486931D2D14271B9E35030B71FD73DA179069B32E2935630E1C2062354D0DA20A6C416E50BE794CA4"; char ptr_y[] = "963F14E32BA5372928F24F15B0730C49D31B28E5C7641002564DB95995B15CF8800ED54E354867B82BB9597B158269E079F0C4F4926B17761CC89EB77C9B7EF8"; if (BN_hex2bn(&dsakeys->p, ptr_p) == 0) return 0; if (BN_hex2bn(&dsakeys->q, ptr_q) == 0) return 0; if (BN_hex2bn(&dsakeys->g, ptr_g) == 0) return 0; if (BN_hex2bn(&dsakeys->pub_key, ptr_y) == 0) return 0; int result; //valid = 1, invalid = 0, error = -1 result = DSA_do_verify(ptr_sha_hashed, 20, dsasig, dsakeys); //result is 0 (invalid)

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• JavaOne 2012: Nashorn Edition

  - by $utils.escapeXML($entry.author)

  As with my JavaOne 2012: OpenJDK Edition post a while back (now updated to reflect the schedule of the talks), I find it convenient to have my JavaOne schedule ordered by subjects of interest. Beside OpenJDK in all its flavors, another subject I find very exciting is Nashorn. I blogged about the various material on Nashorn in the past, and we interviewed Jim Laskey, the Project Lead on Project Nashorn in the Java Spotlight podcast. So without further ado, here are the JavaOne 2012 talks and BOFs with Nashorn in their title, or abstract:CON5390 - Nashorn: Optimizing JavaScript and Dynamic Language Execution on the JVM - Monday, Oct 1, 8:30 AM - 9:30 AMThere are many implementations of JavaScript, meant to run either on the JVM or standalone as native code. Both approaches have their respective pros and cons. The Oracle Nashorn JavaScript project is based on the former approach. This presentation goes through the performance work that has gone on in Oracle’s Nashorn JavaScript project to date in order to make JavaScript-to-bytecode generation for execution on the JVM feasible. It shows that the new invoke dynamic bytecode gets us part of the way there but may not quite be enough. What other tricks did the Nashorn project use? The presentation also discusses future directions for increased performance for dynamic languages on the JVM, covering proposed enhancements to both the JVM itself and to the bytecode compiler.CON4082 - Nashorn: JavaScript on the JVM - Monday, Oct 1, 3:00 PM - 4:00 PMThe JavaScript programming language has been experiencing a renaissance of late, driven by the interest in HTML5. Nashorn is a JavaScript engine implemented fully in Java on the JVM. It is based on the Da Vinci Machine (JSR 292) and will be available with JDK 8. This session describes the goals of Project Nashorn, gives a top-level view of how it all works, provides the current status, and demonstrates examples of JavaScript and Java working together.BOF4763 - Meet the Nashorn JavaScript Team - Tuesday, Oct 2, 4:30 PM - 5:15 PMCome to this session to meet the Oracle JavaScript (Project Nashorn) language teamBOF6661 - Nashorn, Node, and Java Persistence - Tuesday, Oct 2, 5:30 PM - 6:15 PMWith Project Nashorn, developers will have a full and modern JavaScript engine available on the JVM. In addition, they will have support for running Node applications with Node.jar. This unique combination of capabilities opens the door for best-of-breed applications combining Node with Java SE and Java EE. In this session, you’ll learn about Node.jar and how it can be combined with Java EE components such as EclipseLink JPA for rich Java persistence. You’ll also hear about all of Node.jar’s mapping, caching, querying, performance, and scaling features.CON10657 - The Polyglot Java VM and Java Middleware - Thursday, Oct 4, 12:30 PM - 1:30 PMIn this session, Red Hat and Oracle discuss the impact of polyglot programming from their own unique perspectives, examining non-Java languages that utilize Oracle’s Java HotSpot VM. You’ll hear a discussion of topics relating to Ruby, Lisp, and Clojure and the intersection of other languages where they may touch upon individual frameworks and projects, and you’ll get perspectives on JavaScript via the Nashorn Project, an upcoming JavaScript engine, developed fully in Java.CON5251 - Putting the Metaobject Protocol to Work: Nashorn’s Java Bindings - Thursday, Oct 4, 2:00 PM - 3:00 PMProject Nashorn is Oracle’s new JavaScript runtime in Java 8. Being a JavaScript runtime running on the JVM, it provides integration with the underlying runtime by enabling JavaScript objects to manipulate Java objects, implement Java interfaces, and extend Java classes. Nashorn is invokedynamic-based, and for its Java integration, it does away with the concept of wrapper objects in favor of direct virtual machine linking to Java objects’ methods provided by a metaobject protocol, providing much higher performance than what could be expected from a scripting runtime. This session looks at the details of the integration, a topic of interest to other language implementers on the JVM and a wider audience of developers who want to understand how Nashorn works.That's 6 sessions tooting the Nashorn this year at JavaOne, up from 2 last year.

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• What common interface would be appropriate for these game object classes?

  - by Jefffrey

  Question A component based system's goal is to solve the problems that derives from inheritance: for example the fact that some parts of the code (that are called components) are reused by very different classes that, hypothetically, would lie in a very different branch of the inheritance tree. That's a very nice concept, but I've found out that CBS is often hard to accomplish without using ugly hacks. Implementations of this system are often far from clean. But I don't want to discuss this any further. My question is: how can I solve the same problems a CBS try to solve with a very clean interface? (possibly with examples, there are a lot of abstract talks about the "perfect" design already). Context Here's an example I was going for before realizing I was just reinventing inheritance again: class Human { public: Position position; Movement movement; Sprite sprite; // other human specific components }; class Zombie { Position position; Movement movement; Sprite sprite; // other zombie specific components }; After writing that I realized I needed an interface, otherwise I would have needed N containers for N different types of objects (or to use boost::variant to gather them all together). So I've thought of polymorphism (move what systems do in a CBS design into class specific functions): class Entity { public: virtual void on_event(Event) {} // not pure virtual on purpose virtual void on_update(World) {} virtual void on_draw(Window) {} }; class Human : public Entity { private: Position position; Movement movement; Sprite sprite; public: virtual void on_event(Event) { ... } virtual void on_update(World) { ... } virtual void on_draw(Window) { ... } }; class Zombie : public Entity { private: Position position; Movement movement; Sprite sprite; public: virtual void on_event(Event) { ... } virtual void on_update(World) { ... } virtual void on_draw(Window) { ... } }; Which was nice, except for the fact that now the outside world would not even be able to know where a Human is positioned (it does not have access to its position member). That would be useful to track the player position for collision detection or if on_update the Zombie would want to track down its nearest human to move towards him. So I added const Position& get_position() const; to both the Zombie and Human classes. And then I realized that both functionality were shared, so it should have gone to the common base class: Entity. Do you notice anything? Yes, with that methodology I would have a god Entity class full of common functionality (which is the thing I was trying to avoid in the first place). Meaning of "hacks" in the implementation I'm referring to I'm talking about the implementations that defines Entities as simple IDs to which components are dynamically attached. Their implementation can vary from C-stylish: int last_id; Position* positions[MAX_ENTITIES]; Movement* movements[MAX_ENTITIES]; Where positions[i], movements[i], component[i], ... make up the entity. Or to more C++-style: int last_id; std::map<int, Position> positions; std::map<int, Movement> movements; From which systems can detect if an entity/id can have attached components.

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• Apache config that uses two document roots based on whether the requested resource exists in the first [closed]

  - by mattalexx

  Background I have a client site that consists of a CakePHP installation and a Magento installation: /web/example.com/ /web/example.com/app/ <== CakePHP /web/example.com/app/webroot/ <== DocumentRoot /web/example.com/app/webroot/store/ <== Magento /web/example.com/config/ <== Site-wide config /web/example.com/vendors/ <== Site-wide libraries The server runs Apache 2.2.3. The problem The whole company has FTP access and got used to clogging up the /web/example.com/, /web/example.com/app/webroot/, and /web/example.com/app/webroot/store/ directories with their own files. Sometimes these files need HTTP access and sometimes they don't. In any case, this mess makes my job harder when it comes to maintaining the site. Code merges, tarring the live code, etc, is very complicated and usually requires a bunch of filters. Abandoned solution At first, I thought I would set up a new subdomain on the same server, move all of their files there, and change their FTP chroot. But that wouldn't work for these reasons: Firstly, I have no idea (and neither do they remember) what marketing materials they've sent out that contain URLs to certain resources they've uploaded to the server, using the main domain, and also using abstract subdomains that use the main virtual host because it has ServerAlias *.example.com. So suddenly having them only use static.example.com isn't feasible. Secondly, The PHP scripts in their projects are potentially very non-portable. I want their files to stay in as similar an environment as they were built as I can. Also, I do not want to debug their code to make it portable. Half-baked solution After some thought, I decided to find a way to section off the actual website files into another directory that they would not touch. The company's uploaded files would stay where they were. This would ensure that I didn't break any of their projects that needed HTTP access. It would look something like this: /web/example.com/ <== A bunch of their files are in here /web/example.com/app/webroot/ <== 1st DocumentRoot; A bunch of their files are in here /web/example.com/app/webroot/store/ <== Some more are in here /web/example.com/site/ <== New dir; Contains only site files /web/example.com/site/app/ <== CakePHP /web/example.com/site/app/webroot/ <== 2nd DocumentRoot /web/example.com/site/app/webroot/store/ <== Magento /web/example.com/site/config/ <== Site-wide config /web/example.com/site/vendors/ <== Site-wide libraries After I made this change, I would not need to pay attention to anything except for the stuff within /web/example.com/site/ and my job would be a lot easier. I would be the only one changing stuff in there. So here's where the Apache magic would happen: I need an HTTP request to http://www.example.com/ to first use /web/example.com/app/webroot/ as the document root. If nothing is found (no miscellaneous uploaded company projects are found), try finding something within /web/example.com/site/app/webroot/. Another thing to keep in mind is, the site might have some problems if the $_SERVER['DOCUMENT_ROOT'] variable reads /web/example.com/app/webroot/ but the actual files are within /web/example.com/site/app/webroot/. It would be better if the DOCUMENT_ROOT environment variable could be /web/example.com/site/app/webroot/ for anything within the /web/example.com/site/app/webroot/ directory. Conclusion Is my half-baked solution possible with Apache 2.2.3? Is there a better way to solve this problem?

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• Moving StarterSTS to the (Azure) Cloud

  - by Your DisplayName here!

  Quite some people asked me about an Azure version of StarterSTS. While I kinda knew what I had to do to make the move, I couldn’t find the time. Until recently. This blog post briefly documents the necessary changes and design decisions for the next version of StarterSTS which will work both on-premise and on Azure. Provider Fortunately StarterSTS is already based on the idea of “providers”. Authentication, roles and claims generation is based on the standard ASP.NET provider infrastructure. This makes the migration to different data stores less painful. In my case I simply moved the ASP.NET provider database to SQL Azure and still use the standard SQL Server based membership, roles and profile provider. In addition StarterSTS has its own providers to abstract resource access for certificates, relying party registration, client certificate registration and delegation. So I only had to provide new implementations. Signing and SSL keys now go in the Azure certificate store and user mappings (client certificates and delegation settings) have been moved to Azure table storage. The one thing I didn’t anticipate when I originally wrote StarterSTS was the need to also encapsulate configuration. Currently configuration is “locked” to the standard .NET configuration system. The new version will have a pluggable SettingsProvider with versions for .NET configuration as well as Azure service configuration. If you want to externalize these settings into e.g. a database, it is now just a matter of supplying a corresponding provider. Moving between the on-premise and Azure version will be just a matter of using different providers. URL Handling Another thing that’s substantially different on Azure (and load balanced scenarios in general) is the handling of URLs. In farm scenarios, the standard APIs like ASP.NET’s Request.Url return the current (internal) machine name, but you typically need the address of the external facing load balancer. There’s a hotfix for WCF 3.5 (included in v4) that fixes this for WCF metadata. This was accomplished by using the HTTP Host header to generate URLs instead of the local machine name. I now use the same approach for generating WS-Federation metadata as well as information card files. New Features I introduced a cache provider. Since we now have slightly more expensive lookups (e.g. relying party data from table storage), it makes sense to cache certain data in the front end. The default implementation uses the ASP.NET web cache and can be easily extended to use products like memcached or AppFabric Caching. Starting with the relying party provider, I now also provide a read/write interface. This allows building management interfaces on top of this provider. I also include a (very) simple web page that allows working with the relying party provider data. I guess I will use the same approach for other providers in the future as well. I am also doing some work on the tracing and health monitoring area. Especially important for the Azure version. Stay tuned.

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• Pantech Link II, Ubuntu and Virtual XP

  - by user85041

  Okay this is my problem. I have a Pantech Link II, dmesg states: [ 896.072037] usb 2-3: new high-speed USB device number 3 using ehci_hcd [ 896.258562] cdc_acm 2-3:1.0: ttyACM0: USB ACM device [ 896.260039] usbcore: registered new interface driver cdc_acm [ 896.260042] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters Have it installed through wine (pc suite and driver) and it doesn't see it. Virtual XP through VMWare Player sees my device, knows it needs a driver. The removable devices says Curitel Pantech USB Device (Maybe Driver). I have PC Suite installed in XP, I install the driver through the executable.. it says problem with installing hardware, and then it disappears. Ubuntu sees it after restart, but if I start XP with that driver installed, it disappears from both and I get these errors in dmesg: [ 1047.760555] /dev/vmmon[2882]: PTSC: initialized at 3093322000 Hz using TSC, TSCs are synchronized. [ 1048.174033] /dev/vmmon[2882]: Monitor IPI vector: 0 [ 1055.293060] /dev/vmnet: open called by PID 3163 (vmx-vcpu-0) [ 1055.293074] /dev/vmnet: port on hub 8 successfully opened [ 1055.293088] /dev/vmnet: open called by PID 3163 (vmx-vcpu-0) [ 1055.293094] /dev/vmnet: port on hub 8 successfully opened [ 1072.446305] /dev/vmnet: open called by PID 3163 (vmx-vcpu-0) [ 1072.446316] /dev/vmnet: port on hub 8 successfully opened [ 1072.446328] /dev/vmnet: open called by PID 3163 (vmx-vcpu-0) [ 1072.446334] /dev/vmnet: port on hub 8 successfully opened [ 1072.856024] usb 1-1: reset high-speed USB device number 2 using ehci_hcd [ 1079.292024] usb 1-1: reset high-speed USB device number 2 using ehci_hcd [ 1079.732024] usb 1-1: reset high-speed USB device number 2 using ehci_hcd [ 1127.743034] NET: Registered protocol family 39 [ 1127.749320] [3163]: VMCI: IOCTL_VMCI_QUEUEPAIR_ALLOC (cid=1522210225,result=4). [ 1144.104031] usb 2-3: reset high-speed USB device number 3 using ehci_hcd [ 1144.412031] usb 2-3: reset high-speed USB device number 3 using ehci_hcd [ 1155.889976] ehci_hcd 0000:00:13.2: force halt; handshake ffffc90000642024 00004000 00000000 -> -110 [ 1155.889980] ehci_hcd 0000:00:13.2: HC died; cleaning up [ 1155.890008] usb 2-3: USB disconnect, device number 3 [ 1155.890013] usb 2-3: usbfs: usb_submit_urb returned -110 [ 1658.310777] [3163]: VMCI: IOCTL_VMCI_QUEUEPAIR_DETACH (cid=1522210225,result=3). [ 1658.392018] NET: Unregistered protocol family 39 [ 1666.546438] /dev/vmnet: open called by PID 3163 (vmx-vcpu-0) [ 1666.546450] /dev/vmnet: port on hub 8 successfully opened [ 1666.546462] /dev/vmnet: open called by PID 3163 (vmx-vcpu-0) [ 1666.546467] /dev/vmnet: port on hub 8 successfully opened [ 1671.431383] uvcvideo: Found UVC 1.00 device USB2.0 Camera (1871:0101) [ 1671.432533] input: USB2.0 Camera as /devices/pci0000:00/0000:00:12.2/usb1/1-1/1-1:1.0/input/input13 lessa@X:~$ dmesg|tail [ 1155.890008] usb 2-3: USB disconnect, device number 3 [ 1155.890013] usb 2-3: usbfs: usb_submit_urb returned -110 [ 1658.310777] [3163]: VMCI: IOCTL_VMCI_QUEUEPAIR_DETACH (cid=1522210225,result=3). [ 1658.392018] NET: Unregistered protocol family 39 [ 1666.546438] /dev/vmnet: open called by PID 3163 (vmx-vcpu-0) [ 1666.546450] /dev/vmnet: port on hub 8 successfully opened [ 1666.546462] /dev/vmnet: open called by PID 3163 (vmx-vcpu-0) [ 1666.546467] /dev/vmnet: port on hub 8 successfully opened [ 1671.431383] uvcvideo: Found UVC 1.00 device USB2.0 Camera (1871:0101) [ 1671.432533] input: USB2.0 Camera as /devices/pci0000:00/0000:00:12.2/usb1/1-1/1-1:1.0/input/input13 I have tried uninstalling, and installing manually from the device manager update driver while it's still has the warning sign.. it doesn't see the drivers as valid. No idea how to fix this.. would prefer to not have to go to another computer. I'm not trying to do anything but get the pictures off of it. I have to restart ubuntu, plug in device, for ubuntu to see it correctly again. I am like a month and a half old linux newbie so I have no idea the commands I could use for this, and I don't have a memory card in the phone to mount.

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• Patterns for a tree of persistent data with multiple storage options?

  - by Robin Winslow

  I have a real-world problem which I'll try to abstract into an illustrative example. So imagine I have data objects in a tree, where parent objects can access children, and children can access parents: // Interfaces interface IParent<TChild> { List<TChild> Children; } interface IChild<TParent> { TParent Parent; } // Classes class Top : IParent<Middle> {} class Middle : IParent<Bottom>, IChild<Top> {} class Bottom : IChild<Middle> {} // Usage var top = new Top(); var middles = top.Children; // List<Middle> foreach (var middle in middles) { var bottoms = middle.Children; // List<Bottom> foreach (var bottom in bottoms) { var middle = bottom.Parent; // Access the parent var top = middle.Parent; // Access the grandparent } } All three data objects have properties that are persisted in two data stores (e.g. a database and a web service), and they need to reflect and synchronise with the stores. Some objects only request from the web service, some only write to it. Data Mapper My favourite pattern for data access is Data Mapper, because it completely separates the data objects themselves from the communication with the data store: class TopMapper { public Top FetchById(int id) { var top = new Top(DataStore.TopDataById(id)); top.Children = MiddleMapper.FetchForTop(Top); return Top; } } class MiddleMapper { public Middle FetchById(int id) { var middle = new Middle(DataStore.MiddleDataById(id)); middle.Parent = TopMapper.FetchForMiddle(middle); middle.Children = BottomMapper.FetchForMiddle(bottom); return middle; } } This way I can have one mapper per data store, and build the object from the mapper I want, and then save it back using the mapper I want. There is a circular reference here, but I guess that's not a problem because most languages can just store memory references to the objects, so there won't actually be infinite data. The problem with this is that every time I want to construct a new Top, Middle or Bottom, it needs to build the entire object tree within that object's Parent or Children property, with all the data store requests and memory usage that that entails. And in real life my tree is much bigger than the one represented here, so that's a problem. Requests in the object In this the objects request their Parents and Children themselves: class Middle { private List<Bottom> _children = null; // cache public List<Bottom> Children { get { _children = _children ?? BottomMapper.FetchForMiddle(this); return _children; } set { BottomMapper.UpdateForMiddle(this, value); _children = value; } } } I think this is an example of the repository pattern. Is that correct? This solution seems neat - the data only gets requested from the data store when you need it, and thereafter it's stored in the object if you want to request it again, avoiding a further request. However, I have two different data sources. There's a database, but there's also a web service, and I need to be able to create an object from the web service and save it back to the database and then request it again from the database and update the web service. This also makes me uneasy because the data objects themselves are no longer ignorant of the data source. We've introduced a new dependency, not to mention a circular dependency, making it harder to test. And the objects now mask their communication with the database. Other solutions Are there any other solutions which could take care of the multiple stores problem but also mean that I don't need to build / request all the data every time?

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• Is this over-abstraction? (And is there a name for it?)

  - by mwhite

  I work on a large Django application that uses CouchDB as a database and couchdbkit for mapping CouchDB documents to objects in Python, similar to Django's default ORM. It has dozens of model classes and a hundred or two CouchDB views. The application allows users to register a "domain", which gives them a unique URL containing the domain name that gives them access to a project whose data has no overlap with the data of other domains. Each document that is part of a domain has its domain property set to that domain's name. As far as relationships between the documents go, all domains are effectively mutually exclusive subsets of the data, except for a few edge cases (some users can be members of more than one domain, and there are some administrative reports that include all domains, etc.). The code is full of explicit references to the domain name, and I'm wondering if it would be worth the added complexity to abstract this out. I'd also like to know if there's a name for the sort of bound property approach I'm taking here. Basically, I have something like this in mind: Before in models.py class User(Document): domain = StringProperty() class Group(Document): domain = StringProperty() name = StringProperty() user_ids = StringListProperty() # method that returns related document set def users(self): return [User.get(id) for id in self.user_ids] # method that queries a couch view optimized for a specific lookup @classmethod def by_name(cls, domain, name): # the view method is provided by couchdbkit and handles # wrapping json CouchDB results as Python objects, and # can take various parameters modifying behavior return cls.view('groups/by_name', key=[domain, name]) # method that creates a related document def get_new_user(self): user = User(domain=self.domain) user.save() self.user_ids.append(user._id) return user in views.py: from models import User, Group # there are tons of views like this, (request, domain, ...) def create_new_user_in_group(request, domain, group_name): group = Group.by_name(domain, group_name)[0] user = User(domain=domain) user.save() group.user_ids.append(user._id) group.save() in group/by_name/map.js: function (doc) { if (doc.doc_type == "Group") { emit([doc.domain, doc.name], null); } } After models.py class DomainDocument(Document): domain = StringProperty() @classmethod def domain_view(cls, *args, **kwargs): kwargs['key'] = [cls.domain.default] + kwargs['key'] return super(DomainDocument, cls).view(*args, **kwargs) @classmethod def get(cls, *args, **kwargs, validate_domain=True): ret = super(DomainDocument, cls).get(*args, **kwargs) if validate_domain and ret.domain != cls.domain.default: raise Exception() return ret def models(self): # a mapping of all models in the application. accessing one returns the equivalent of class BoundUser(User): domain = StringProperty(default=self.domain) class User(DomainDocument): pass class Group(DomainDocument): name = StringProperty() user_ids = StringListProperty() def users(self): return [self.models.User.get(id) for id in self.user_ids] @classmethod def by_name(cls, name): return cls.domain_view('groups/by_name', key=[name]) def get_new_user(self): user = self.models.User() user.save() views.py @domain_view # decorator that sets request.models to the same sort of object that is returned by DomainDocument.models and removes the domain argument from the URL router def create_new_user_in_group(request, group_name): group = request.models.Group.by_name(group_name) user = request.models.User() user.save() group.user_ids.append(user._id) group.save() (Might be better to leave the abstraction leaky here in order to avoid having to deal with a couchapp-style //! include of a wrapper for emit that prepends doc.domain to the key or some other similar solution.) function (doc) { if (doc.doc_type == "Group") { emit([doc.name], null); } } Pros and Cons So what are the pros and cons of this? Pros: DRYer prevents you from creating related documents but forgetting to set the domain. prevents you from accidentally writing a django view - couch view execution path that leads to a security breach doesn't prevent you from accessing underlying self.domain and normal Document.view() method potentially gets rid of the need for a lot of sanity checks verifying whether two documents whose domains we expect to be equal are. Cons: adds some complexity hides what's really happening requires no model modules to have classes with the same name, or you would need to add sub-attributes to self.models for modules. However, requiring project-wide unique class names for models should actually be fine because they correspond to the doc_type property couchdbkit uses to decide which class to instantiate them as, which should be unique. removes explicit dependency documentation (from group.models import Group)

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• Too complex/too many objects?

  - by Mike Fairhurst

  I know that this will be a difficult question to answer without context, but hopefully there are at least some good guidelines to share on this. The questions are at the bottom if you want to skip the details. Most are about OOP in general. Begin context. I am a jr dev on a PHP application, and in general the devs I work with consider themselves to use many more OO concepts than most PHP devs. Still, in my research on clean code I have read about so many ways of using OO features to make code flexible, powerful, expressive, testable, etc. that is just plain not in use here. The current strongly OO API that I've proposed is being called too complex, even though it is trivial to implement. The problem I'm solving is that our permission checks are done via a message object (my API, they wanted to use arrays of constants) and the message object does not hold the validation object accountable for checking all provided data. Metaphorically, if your perm containing 'allowable' and 'rare but disallowed' is sent into a validator, the validator may not know to look for 'rare but disallowed', but approve 'allowable', which will actually approve the whole perm check. We have like 11 validators, too many to easily track at such minute detail. So I proposed an AtomicPermission class. To fix the previous example, the perm would instead contain two atomic permissions, one wrapping 'allowable' and the other wrapping 'rare but disallowed'. Where previously the validator would say 'the check is OK because it contains allowable,' now it would instead say '"allowable" is ok', at which point the check ends...and the check fails, because 'rare but disallowed' was not specifically okay-ed. The implementation is just 4 trivial objects, and rewriting a 10 line function into a 15 line function. abstract class PermissionAtom { public function allow(); // maybe deny() as well public function wasAllowed(); } class PermissionField extends PermissionAtom { public function getName(); public function getValue(); } class PermissionIdentifier extends PermissionAtom { public function getIdentifier(); } class PermissionAction extends PermissionAtom { public function getType(); } They say that this is 'not going to get us anything important' and it is 'too complex' and 'will be difficult for new developers to pick up.' I respectfully disagree, and there I end my context to begin the broader questions. So the question is about my OOP, are there any guidelines I should know: is this too complicated/too much OOP? Not that I expect to get more than 'it depends, I'd have to see if...' when is OO abstraction too much? when is OO abstraction too little? how can I determine when I am overthinking a problem vs fixing one? how can I determine when I am adding bad code to a bad project? how can I pitch these APIs? I feel the other devs would just rather say 'its too complicated' than ask 'can you explain it?' whenever I suggest a new class.

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• Javascript Inheritance Part 2

  - by PhubarBaz

  A while back I wrote about Javascript inheritance, trying to figure out the best and easiest way to do it (http://geekswithblogs.net/PhubarBaz/archive/2010/07/08/javascript-inheritance.aspx). That was 2 years ago and I've learned a lot since then. But only recently have I decided to just leave classical inheritance behind and embrace prototypal inheritance. For most of us, we were trained in classical inheritance, using class hierarchies in a typed language. Unfortunately Javascript doesn't follow that model. It is both classless and typeless, which is hard to fathom for someone who's been using classes the last 20 years. For the last two or three years since I've got into Javascript I've been trying to find the best way to force it into the class model without much success. It's clunky and verbose and hard to understand. I think my biggest problem was that it felt so wrong to add or change object members at run time. Every time I did it I felt like I needed a shower. That's the 20 years of classical inheritance in me. Finally I decided to embrace change and do something different. I decided to use the factory pattern to build objects instead of trying to use inheritance. Javascript was made for the factory pattern because of the way you can construct objects at runtime. In the factory pattern you have a factory function that you call and tell it to give you a certain type of object back. The factory function takes care of constructing the object to your specification. Here's an example. Say we want to have some shape objects and they have common attributes like id and area that we want to depend on in other parts of your application. So first thing to do is create a factory object and give it a factory method to create an abstract shape object. The factory method builds the object then returns it. var shapeFactory = { getShape: function(id){ var shape = { id: id, area: function() { throw "Not implemented"; } }; return shape; }}; Now we can add another factory method to get a rectangle. It calls the getShape() method first and then adds an implementation to it. getRectangle: function(id, width, height){ var rect = this.getShape(id); rect.width = width; rect.height = height; rect.area = function() { return this.width * this.height; }; return rect;} That's pretty simple right? No worrying about hooking up prototypes and calling base constructors or any of that crap I used to do. Now let's create a factory method to get a cuboid (rectangular cube). The cuboid object will extend the rectangle object. To get the area we will call into the base object's area method and then multiply that by the depth. getCuboid: function(id, width, height, depth){ var cuboid = this.getRectangle(id, width, height); cuboid.depth = depth; var baseArea = cuboid.area; cuboid.area = function() { var a = baseArea.call(this); return a * this.depth; } return cuboid;} See how we called the area method in the base object? First we save it off in a variable then we implement our own area method and use call() to call the base function. For me this is a lot cleaner and easier than trying to emulate class hierarchies in Javascript.

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• Is my class structure good enough?

  - by Rivten

  So I wanted to try out this challenge on reddit which is mostly about how you structure your data the best you can. I decided to challenge my C++ skills. Here's how I planned this. First, there's the Game class. It deals with time and is the only class main has access to. A game has a Forest. For now, this class does not have a lot of things, only a size and a Factory. Will be put in better use when it will come to SDL-stuff I guess A Factory is the thing that deals with the Game Objects (a.k.a. Trees, Lumberjack and Bears). It has a vector of all GameObjects and a queue of Events which will be managed at the end of one month. A GameObject is an abstract class which can be updated and which can notify the Event Listener The EventListener is a class which handles all the Events of a simulation. It can recieve events from a Game Object and notify the Factory if needed, the latter will manage correctly the event. So, the Tree, Lumberjack and Bear classes all inherits from GameObject. And Sapling and Elder Tree inherits from Tree. Finally, an Event is defined by an event_type enumeration (LUMBERJACK_MAWED, SAPPLING_EVOLUTION, ...) and an event_protagonists union (a GameObject or a pair of GameObject (who killed who ?)). I was quite happy at first with this because it seems quite logic and flexible. But I ended up questionning this structure. Here's why : I dislike the fact that a GameObject need to know about the Factory. Indeed, when a Bear moves somewhere, it needs to know if there's a Lumberjack ! Or it is the Factory which handles places and objects. It would be great if a GameObject could only interact with the EventListener... or maybe it's not that much of a big deal. Wouldn't it be better if I separate the Factory in three vectors ? One for each kind of GameObject. The idea would be to optimize research. If I'm looking do delete a dead lumberjack, I would only have to look in one shorter vector rather than a very long vector. Another problem arises when I want to know if there is any particular object in a given case because I have to look for all the gameObjects and see if they are at the given case. I would tend to think that the other idea would be to use a matrix but then the issue would be that I would have empty cases (and therefore unused space). I don't really know if Sapling and Elder Tree should inherit from Tree. Indeed, a Sapling is a Tree but what about its evolution ? Should I just delete the sapling and say to the factory to create a new Tree at the exact same place ? It doesn't seem natural to me to do so. How could I improve this ? Is the design of an Event quite good ? I've never used unions before in C++ but I didn't have any other ideas about what to use. Well, I hope I have been clear enough. Thank you for taking the time to help me !

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• Rails3 server and bundler error: uninitialized constant Bundler (NameError)

  - by .yandex.rurap-kasta

  I just install rails 3 and all gems that it need, but when I try to start server, it says about problem in boot script. [rap-kasta@acerAspire testR3]$ script/rails server /home/rap-kasta/tmp/testR3/config/boot.rb:7:in `rescue in <top (required)>': uninitialized constant Bundler (NameError) from /home/rap-kasta/tmp/testR3/config/boot.rb:2:in `<top (required)>' from script/rails:9:in `require' from script/rails:9:in `<main> So, I tried to reinstall Bundler, install "pre"-version (but really it has version number lower then i install by gem install bundler Now there are next gems in system: abstract (1.0.0) actionmailer (3.0.0.beta, 2.3.5, 2.3.4) actionpack (3.0.0.beta, 2.3.5, 2.3.4) activemodel (3.0.0.beta) activerecord (3.0.0.beta, 2.3.5, 2.3.4) activeresource (3.0.0.beta, 2.3.5, 2.3.4) activesupport (3.0.0.beta, 2.3.5, 2.3.4) arel (0.2.1, 0.2.pre) builder (2.1.2) bundler (0.9.5) erubis (2.6.5) fxri (0.3.7) fxruby (1.6.20) i18n (0.3.3) jemini (2010.1.24, 2010.1.5) mail (2.1.2) memcache-client (1.7.8) mime-types (1.16) mysql (2.8.1) nifty-generators (0.3.2, 0.3.0) rack (1.1.0, 1.0.1, 1.0.0) rack-mount (0.5.1, 0.4.0) rack-openid (0.2.3, 0.2.2) rack-test (0.5.3) rails (3.0.0.beta, 2.3.5, 2.3.4) railties (3.0.0.beta) rake (0.8.7) rawr (1.3.8) RedCloth (4.2.2) ruby-mysql (3.0.2) ruby-openid (2.1.7) rubygems-update (1.3.5) rubyzip (0.9.4, 0.9.1) rubyzip2 (2.0.1) sqlite3-ruby (1.2.5) text-format (1.0.0) text-hyphen (1.0.0) thor (0.13.2, 0.13.1) tzinfo (0.3.16) Also, there is same error with rails console and similar with bundle check: [rap-kasta@acerAspire testR3]$ bundle check /usr/lib/ruby/gems/1.9.1/gems/bundler-0.9.5/bin/bundle:12:in `rescue in <top (required)>': uninitialized constant Bundler::BundlerError (NameError) from /usr/lib/ruby/gems/1.9.1/gems/bundler-0.9.5/bin/bundle:10:in `<top (required)>' from /usr/bin/bundle:19:in `load' from /usr/bin/bundle:19:in `<main>'

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• 'EditItem' is not allowed for this view - databinding issue

  - by Pawan

  Hi, I am trying to do data binding in WPF on data grid using a cutom list. My custom list class contains a private data list of type List. I can not expose this list however the indexers are exposed for seeting and getting individual items. My custom class looks like this: public abstract class TestElementList<T> : IEnumerable where T : class { protected List<T> Data { get; set; } public virtual T Get(int index) { T item = Data[index]; return item; } public virtual void Set(int index, T item) { Data[index] = item; } ... } The data is binded but when I try to edit it, i get "'EditItem' is not allowed for this view." Error. On doing extensive searching over web, I found that i might need to implement IEditableCollectionView interface also. Can anybody please help me to either give pointers on how to implement this interface or any suggest any other better way to do databinding on custom list. Thanks in advance.

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• WPF MVVM UserControl Binding "Container", dispose to avoid memory leak.

  - by user178657

  For simplicity. I have a window, with a bindable usercontrol <UserControl Content="{Binding Path = BindingControl, UpdateSourceTrigger=PropertyChanged}"> I have two user controls, ControlA, and ControlB, Both UserControls have their own Datacontext ViewModel, ControlAViewModel and ControlBViewModel. Both ControlAViewModel and ControlBViewModel inh. from a "ViewModelBase" public abstract class ViewModelBase : DependencyObject, INotifyPropertyChanged, IDisposable........ Main window was added to IoC... To set the property of the Bindable UC, i do ComponentRepository.Resolve<MainViewWindow>().Bindingcontrol= new ControlA; ControlA, in its Datacontext, creates a DispatcherTimer, to do "somestuff".. Later on., I need to navigate elsewhere, so the other usercontrol is loaded into the container ComponentRepository.Resolve<MainViewWindow>().Bindingcontrol= new ControlB If i put a break point in the "someStuff" that was in ControlA's datacontext. The DispatcherTimer is still running... i.e. loading a new usercontrol into the bindable Usercontrol on mainwindow does not dispose/close/GC the DispatcherTimer that was created in the DataContext View Model... Ive looked around, and as stated by others, dispose doesnt get called because its not supposed to... :) Not all my usercontrols have DispatcherTimer, just a few that need to do some sort of "read and refresh" updates./. Should i track these DispatcherTimer objects in the ViewModelBase that all Usercontrols inh. and manually stop/dispose them everytime a new usercontrol is loaded? Is there a better way?

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• WCF service dataContractSerializer maxItemsInObjectGraph in web.config

  - by Dave

  I am having issues specifying the dataContractSerializer maxItemsInObjectGraph in host's web.config. <behaviors> <serviceBehaviors> <behavior name="beSetting"> <serviceMetadata httpGetEnabled="True"/> <serviceDebug includeExceptionDetailInFaults="True" /> <dataContractSerializer maxItemsInObjectGraph="2147483646"/> </behavior> </serviceBehaviors> </behaviors> <services> <service name="MyNamespace.MyService" behaviorConfiguration="beSetting" > <endpoint address="http://localhost/myservice/" binding="webHttpBinding" bindingConfiguration="webHttpBinding1" contract="MyNamespace.IMyService" bindingNamespace="MyNamespace"> </endpoint> </service> </services> The above has no effect on my data pull. The server times out because of the large volume of data. I can however specify the max limit in code and that works [ServiceBehavior(MaxItemsInObjectGraph=2147483646, IncludeExceptionDetailInFaults = true)] public abstract class MyService : MyService { blah... } Does anyone know why I can't make this work through a web.config setting? I would like to keep in the web.config so it is easier for future updates.

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• Multi tenant membership provider ASP.NET MVC

  - by Masna

  Hello, I'm building a multi-tenant app with ASP.NET MVC and have a problem with validating users. Situation I have: -a table with User(ID, Name, FirstName, Email) This table is made, so that a users who is registered in two tenants doesn't need to login again. -a table with Tentantuser(ID, TenantID, UserID (FK to table User), UserName, Loginname, Password, Active) This table contains de login en password for one tenant. Example: UserX is registered in TenantA and TenantB UserX logs in on TenantA, with his login and password for TenantA System verifies or login and password are correct in the table TenantUser System validates UserX which userID corresponds to the Id in the table User UserX goes to TenantB and is automatically logged in My problem: How can I create a custom Provider so I can check the login & password in a tenant? For example: public abstract bool ValidateUser(string username,string password); How can I say to my provider on which tenant the user is? How can I change this in something like: public overrides bool ValidateUser(string username,string password, string tenant); ? Or what is another way to solve this issue?

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• Hibernate 3.5-Final in JBoss 5.1.0.GA

  - by Bozhidar Batsov

  Hibernate 3.5-Final is finally here and it offers the much anticipated JPA2 support, amongst other features. I am working on a project(EJB3 based) using JBoss 5.1.0.GA and Hibernate 3.3, but I wanted to take advantage of the JPA2 and tried to upgrade to Hibernate 3.5. What I did was fairly simple and standard - I just put all the hibernate 3.5 jars in the server/configuration(default,all,etc)/lib folder - that way they take precedence over the hibernate artifacts shipped with JBoss. It seems though that JBoss ships with libraries that are dependent on the JPA1 implementation part of the hibernate 3.3, because I started getting some errors about unimplemented abstract methods and stuff like that on deploy: 23:21:26,792 WARN [Ejb3Configuration] Persistence provider caller does not implement the EJB3 spec correctly. PersistenceUnitInfo.getNewTempClassLoader() is null. 23:21:26,792 ERROR [AbstractKernelController] Error installing to Start: name=persistence.unit:unitName=kernel-ear-3.3.0-SNAPSHOT.ear/config-persistence.jar#ConfigurationPersistenceUnit state=Create java.lang.AbstractMethodError: org.jboss.jpa.deployment.PersistenceUnitInfoImpl.getValidationMode()Ljavax/persistence/ValidationMode; at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:613) at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:72) at org.jboss.jpa.deployment.PersistenceUnitDeployment.start(PersistenceUnitDeployment.java:301) at sun.reflect.GeneratedMethodAccessor308.invoke(Unknown Source) Maybe I should use a different persistence provided? Currently it's: org.hibernate.ejb.HibernatePersistence I looked around the net and didn't find any documented upgrade paths. There was even an unanswered question here in stack overflow on the topic. Any ideas, suggestions? Thanks in advance for your help.

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• Serialize C# dynamic object to JSON object to be consumed by javascript

  - by Jeff Jin

  Based on the example c# dynamic with XML, I modified DynamicXml.cs and parsed my xml string. the modified part is as follows public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; if (binder.Name == "Controls") result = new DynamicXml(_elements.Elements()); else if (binder.Name == "Count") result = _elements.Count; else { var attr = _elements[0].Attribute( XName.Get(binder.Name)); if (attr != null) result = attr.Value; else { var items = _elements.Descendants( XName.Get(binder.Name)); if (items == null || items.Count() == 0) return false; result = new DynamicXml(items); } } return true; } The xml string to parse: "< View runat='server' Name='Doc111'>" + "< Caption Name='Document.ConvertToPdf' Value='Allow Conversion to PDF'></ Caption>" + "< Field For='Document.ConvertToPdf' ReadOnly='False' DisplayAs='checkbox' EditAs='checkbox'></ Field>" + "< Field For='Document.Abstract' ReadOnly='False' DisplayAs='label' EditAs='textinput'></ Field>" + "< Field For='Document.FileName' ReadOnly='False' DisplayAs='label' EditAs='textinput'></ Field>" + "< Field For='Document.KeyWords' ReadOnly='False' DisplayAs='label' EditAs='textinput'></ Field>" + "< FormButtons SaveCaption='Save' CancelCaption='Cancel'></ FormButtons>" + "</ View>"; dynamic form = new DynamicXml(markup_fieldsOnly); is there a way to serialize the content of this dynamic object(name value pairs inside dynamic) form as JSON object and sent to client side(browser)?

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• Undefined control sequence

  - by Jelle Fresen

  Hi, I am making my Master's Thesis with LaTeX, but I can't get the provided style to work. Specifically, I get the error 'Undefined control sequence' when using the function makeformaltitlepages, which is defined in mscthesis.sty. On the internet, the only answer I could find is the straightforward 'you probably made a typo', or 'you probably forgot to include the package', but I have reason to believe neither of those apply to me. I am quite sure that the function exists, for when I add a little verification, using the @ifundefined command, the logfile shows that the function actually does exist. And, as can be seen in the following piece of code, I also include the package: \usepackage{mscthesis} % setup information like author, company, title, etc. \begin{document} \formatmatter \thispagestyle{empty} \maketitle \makeatletter \@ifundefined{makeformaltitlepages}{\message{Function is not defined.}}{\message{Function is defined.}} \makeatother \makeformaltitlepages{\input{abstract}} % add chapters, sections, etc. and end the document Now, the output shows the line "Function is defined." just before the output of maketitle (which I think is rather strange on its own, but that might be a flushing issue), followed by the following infinitely repeated error (well, cut off after 100 times by LaTeX): Function is defined. // some gibberish about font info ! Undefined control sequence. \GenericError ... #4 \errhelp \@err@ ... l.112 \makeformaltitlepages{} The control sequence at the end of the top line of your error message was never \def'ed. If you have misspelled it (e.g., `\hobx'), type `I' and the correct spelling (e.g., `I\hbox'). Otherwise just continue, and I'll forget about whatever was undefined. While the error keeps repeating, the line that starts with '#4' cycles between the following four lines: #4 \errhelp \@err@ ... \let \@err@ ... \@empty \def \MessageBreak... \endgroup Ok, so, do any of you have a suggestion of how I might continue to hunt this bug? Or what blatantly obvious mistake did I make?

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• MVC: Nested Views, and Controllers (for a website)

  - by incrediman

  I'm doing a PHP website using the MVC pattern. I am not using a framework as the site is fairly simple and I feel that this will give me a good opportunity to learn about the pattern directly. I have a couple questions. Question 1: How should I organize my views? I'm thinking of having a Page view which will have the header and footer, and which will allow for a Content view to be nested between them. Question 2: If I have 5 Content pages, should I make 5 different views that can be used as the content that is nested within the Page view? Or, should I make them all extend an abstract view called AbstractContent? Question 3: What about controllers? I think there should be one main controller at least. But then where does the request go from there? To another controller? Or should I just call the Page view and leave it at that? I thought that controllers were supposed to handle input, possibly modify a model, and select a view. But what if one of the views nested within the view that a controller calls requires additional input to be parsed? Question 4: Are controllers allowed to pass parameters into the view? Or should the controller simply modify the model, which will then affect the view? Or is the model only for DB access and other such things?

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• POST from edit/create partial views loaded into Twitter Bootstrap modal

  - by mare

  I'm struggling with AJAX POST from the form that was loaded into Twitter Bootstrap modal dialog. Partial view form goes like this: @using (Html.BeginForm()) { // fields // ... // submit <input type="submit" value="@ButtonsRes.button_save" /> } Now this is being used in non AJAX editing with classic postbacks. Is it possible to use the same partial for AJAX functionality? Or should I abstract away the inputs into it's own partial view? Like this: @using (Ajax.BeginForm()) { @Html.Partial("~/Views/Shared/ImageEditInputs.cshtml") // but what to do with this one then? <input type="submit" value="@ButtonsRes.button_save" /> } I know how to load this into Bootstrap modal but few changes should be done on the fly: the buttons in Bootstrap modal should be placed in a special container (the modal footer), the AJAX POST should be done when clicking Save which would first, validate the form and keep the modal opened if not valid (display the errors of course) second, post and close the modal if everything went fine in the view that opened the modal, display some feedback information at the top that save was succesful. I'm mostly struggling where to put what JS code. So far I have this within the List view, which wires up the modals: $(document).ready(function () { $('.openModalDialog').click(function (event) { event.preventDefault(); var url = $(this).attr('href'); $.get(url, function (data) { $('#modalContent').html(data); $('#modal').modal('show'); }); }); }); The above code, however, doesn't take into the account the special Bootstrap modal content placeholder (header, content, footer). Is it possible to achieve what I want without having multiple partial views with the same inputs but different @using and without having to do hacks with moving the Submit button around?

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