Search Results

Search found 4960 results on 199 pages for 'onion architecture'.

Page 27/199 | < Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34  | Next Page >

• Characteristics of a Web service that promote reusability and change

  Characteristics of a Web service that promote reusability and change:  Standardized Data Exchange Formats (XML, JSON) Standardized communication protocols (Soap, Rest) Promotes Loosely Coupled Systems  Standardized Data Exchange Formats (XML, JSON) XML W3.org defines Extensible Markup Language (XML) as a simplistic text format derived from SGML. XML was designed to solve challenges found in large-scale electronic publishing. In addition,  XML is playing an important role in the exchange of data primarily focusing on data exchange on the web. JSON JavaScript Object Notation (JSON) is a human-readable text-based standard designed for data interchange. This format is used for serializing and transmitting data over a network connection in a structured format. The primary use of JSON is to transmit data between a server and web application. JSON is an alternative to XML. Standardized communication protocols (Soap, Rest) Soap W3Scools.com defines SOAP as a simple XML-based protocol. This protocol lets applications exchange data over HTTP.  SOAP provides a way to communicate between applications running on different operating systems, with different technologies and programming languages. Rest In 2007, Stefan Tilkov defines Representational State Transfer (REST) as a set of principles that outlines how Web standards are supposed to be used.  Using REST in an application will ensure that it exploits the Web’s architecture to its benefit. Promotes Loosely Coupled Systems “Loose coupling as an approach to interconnecting the components in a system or network so that those components, also called elements, depend on each other to the least extent practicable. Coupling refers to the degree of direct knowledge that one element has of another.” (TechTarget.com, 2007) “Loosely coupled system can be easily broken down into definable elements. The extent of coupling in a system can be measured by mapping the maximum number of element changes that can occur without adverse effects. Examples of such changes include adding elements, removing elements, renaming elements, reconfiguring elements, modifying internal element characteristics and rearranging the way in which elements are interconnected.” (TechTarget.com, 2007) References: W3C. (2011). Extensible Markup Language (XML). Retrieved from W3.org: http://www.w3.org/XML/ W3Scools.com. (2011). SOAP Introduction. Retrieved from W3Scools.com: http://www.w3schools.com/soap/soap_intro.asp Tilkov, Stefan. (2007). A Brief Introduction to REST. Retrieved from Infoq.com: http://www.infoq.com/articles/rest-introduction TechTarget.com. (2011). loose coupling. Retrieved from TechTarget.com: http://searchnetworking.techtarget.com/definition/loose-coupling

  Read the article

• How do you manage extensibility in your multi-tenant systems?

  - by Brian MacKay

  I've got a few big web based multi-tenant products now, and very soon I can see that there will be a lot of customizations that are tenant specific. An extra field here or there, maybe an extra page or some extra logic in the middle of a workflow - that sort of thing. Some of these customizations can be rolled into the core product, and that's great. Some of them are highly specific and would get in everyone else's way. I have a few ideas in mind for managing this, but none of them seem to scale well. The obvious solution is to introduce a ton of client-level settings, allowing various 'features' to be enabled on per-client basis. The downside with that, of course, is massive complexity and clutter. You could introduce a truly huge number of settings, and over time various types of logic (presentation, business) could get way out of hand. Then there's the problem of client-specific fields, which begs for something cleaner than just adding a bunch of nullable fields to the existing tables. So what are people doing to manage this? Force.com seems to be the master of extensibility; obviously they've created a platform from the ground up that is super extensible. You can add on to almost anything with their web-based UI. FogBugz did something similiar where they created a robust plugin model that, come to think of it, might have actually been inspired by Force. I know they spent a lot of time and money on it and if I'm not mistaken the intention was to actually use it internally for future product development. Sounds like the kind of thing I could be tempted to build but probably shouldn't. :) Is a massive investment in pluggable architecture the only way to go? How are you managing these problems, and what kind of results are you seeing? EDIT: It does look as though FogBugz handled the problem by building a fairly robust platform and then using that to put together their screens. To extend it you create a DLL containing classes that implement interfaces like ISearchScreenGridColumn, and that becomes a module. I'm sure it was tremendously expensive to build considering that they have a large of devs and they worked on it for months, plus their surface area is perhaps 5% of the size of my application. Right now I am seriously wondering if Force.com is the right way to handle this. And I am a hard core ASP.Net guy, so this is a strange position to find myself in.

  Read the article

• Single Responsibility Principle Implementation

  - by Mike S

  In my spare time, I've been designing a CMS in order to learn more about actual software design and architecture, etc. Going through the SOLID principles, I already notice that ideas like "MVC", "DRY", and "KISS", pretty much fall right into place. That said, I'm still having problems deciding if one of two implementations is the best choice when it comes to the Single Responsibility Principle. Implementation #1: class User getName getPassword getEmail // etc... class UserManager create read update delete class Session start stop class Login main class Logout main class Register main The idea behind this implementation is that all user-based actions are separated out into different classes (creating a possible case of the aptly-named Ravioli Code), but following the SRP to a "tee", almost literally. But then I thought that it was a bit much, and came up with this next implementation class UserView extends View getLogin //Returns the html for the login screen getShortLogin //Returns the html for an inline login bar getLogout //Returns the html for a logout button getRegister //Returns the html for a register page // etc... as needed class UserModel extends DataModel implements IDataModel // Implements no new methods yet, outside of the interface methods // Haven't figured out anything special to go here at the moment // All CRUD operations are handled by DataModel // through methods implemented by the interface class UserControl extends Control implements IControl login logout register startSession stopSession class User extends DataObject getName getPassword getEmail // etc... This is obviously still very organized, and still very "single responsibility". The User class is a data object that I can manipulate data on and then pass to the UserModel to save it to the database. All the user data rendering (what the user will see) is handled by UserView and it's methods, and all the user actions are in one space in UserControl (plus some automated stuff required by the CMS to keep a user logged in or to ensure that they stay out.) I personally can't think of anything wrong with this implementation either. In my personal feelings I feel that both are effectively correct, but I can't decide which one would be easier to maintain and extend as life goes on (despite leaning towards Implementation #1.) So what about you guys? What are your opinions on this? Which one is better? What basics (or otherwise, nuances) of that principle have I missed in either design?

  Read the article

• How to keep a data structure synchronized over a network?

  - by David Gouveia

  Context In the game I'm working on (a sort of a point and click graphic adventure), pretty much everything that happens in the game world is controlled by an action manager that is structured a bit like: So for instance if the result of examining an object should make the character say hello, walk a bit and then sit down, I simply spawn the following code: var actionGroup = actionManager.CreateGroup(); actionGroup.Add(new TalkAction("Guybrush", "Hello there!"); actionGroup.Add(new WalkAction("Guybrush", new Vector2(300, 300)); actionGroup.Add(new SetAnimationAction("Guybrush", "Sit")); This creates a new action group (an entire line in the image above) and adds it to the manager. All of the groups are executed in parallel, but actions within each group are chained together so that the second one only starts after the first one finishes. When the last action in a group finishes, the group is destroyed. Problem Now I need to replicate this information across a network, so that in a multiplayer session, all players see the same thing. Serializing the individual actions is not the problem. But I'm an absolute beginner when it comes to networking and I have a few questions. I think for the sake of simplicity in this discussion we can abstract the action manager component to being simply: var actionManager = new List<List<string>>(); How should I proceed to keep the contents of the above data structure syncronized between all players? Besides the core question, I'm also having a few other concerns related to it (i.e. all possible implications of the same problem above): If I use a server/client architecture (with one of the players acting as both a server and a client), and one of the clients has spawned a group of actions, should he add them directly to the manager, or only send a request to the server, which in turn will order every client to add that group? What about packet losses and the like? The game is deterministic, but I'm thinking that any discrepancy in the sequence of actions executed in a client could lead to inconsistent states of the world. How do I safeguard against that sort of problem? What if I add too many actions at once, won't that cause problems for the connection? Any way to alleviate that?

  Read the article

• Separating logic and data in browser game

  - by Tesserex

  I've been thinking this over for days and I'm still not sure what to do. I'm trying to refactor a combat system in PHP (...sorry.) Here's what exists so far: There are two (so far) types of entities that can participate in combat. Let's just call them players and NPCs. Their data is already written pretty well. When involved in combat, these entities are wrapped with another object in the DB called a Combatant, which gives them information about the particular fight. They can be involved in multiple combats at once. I'm trying to write the logic engine for combat by having combatants injected into it. I want to be able to mock everything for testing. In order to separate logic and data, I want to have two interfaces / base classes, one being ICombatantData and the other ICombatantLogic. The two implementers of data will be one for the real objects stored in the database, and the other for my mock objects. I'm now running into uncertainties with designing the logic side of things. I can have one implementer for each of players and NPCs, but then I have an issue. A combatant needs to be able to return the entity that it wraps. Should this getter method be part of logic or data? I feel strongly that it should be in data, because the logic part is used for executing combat, and won't be available if someone is just looking up information about an upcoming fight. But the data classes only separate mock from DB, not player from NPC. If I try having two child classes of the DB data implementer, one for each entity type, then how do I architect that while keeping my mocks in the loop? Do I need some third interface like IEntityProvider that I inject into the data classes? Also with some of the ideas I've been considering, I feel like I'll have to put checks in place to make sure you don't mismatch things, like making the logic for an NPC accidentally wrap the data for a player. Does that make any sense? Is that a situation that would even be possible if the architecture is correct, or would the right design prohibit that completely so I don't need to check for it? If someone could help me just layout a class diagram or something for this it would help me a lot. Thanks. edit Also useful to note, the mock data class doesn't really need the Entity, since I'll just be specifying all the parameters like combat stats directly instead. So maybe that will affect the correct design.

  Read the article

• Keeping your options open in a cloud solution

  - by BuckWoody

  In on-premises solutions we have the full range of options open for a given computing solution – but we don’t always take advantage of them, for multiple reasons. Data goes in a Relational Database Management System, files go on a share, and e-mail goes to the Exchange server. Over time, vendors (including ourselves) add in functionality to one product that allow non-standard use of the platform. For example, SQL Server (and Oracle, and others) allow large binary storage in or through the system – something not originally intended for an RDBMS to handle. There are certainly times when this makes sense, of course, but often these platform hammers turn every problem into a nail. It can make us “lazy” in our design – we sometimes don’t take the time to learn another architecture because the one we’ve spent so much time with can handle what we want to do. But there’s a distinct danger here. In nature, when a population shares too many of the same traits, it can cause a complete collapse if a situation exploits a weakness shared by that population. The same is true with not using the righttool for the job in a computing environment. Your company or organization depends on your knowledge as a professional to select the best mix of supportable, flexible, cost-effective technologies to solve their problems, whether you’re in an architect role or not.  So take some time today to learn something new. The way I do this is to select a given problem, and try to solve it with a technology I’m not familiar with. For instance – create a Purchase Order system in Excel, then in Hadoop or MongoDB, or even in flat-files using PowerShell as an interface. No, I’m not suggesting any of these architectures are the proper way to solve the PO problem, but taking something concrete that you know well and applying that meta-knowledge to another platform will assist you in exercising the “little grey cells” and help you and your organization understand what is open to you. And of course you can do all of this on-premises – but my recommendation is to check out a cloud platform (my suggestion would of course be Windows Azure :) ) and try it there. Most providers (including Microsoft) provide free time to do that.

  Read the article

• Architecture for Qt SIGNAL with subclass-specific, templated argument type

  - by Barry Wark

  I am developing a scientific data acquisition application using Qt. Since I'm not a deep expert in Qt, I'd like some architecture advise from the community on the following problem: The application supports several hardware acquisition interfaces but I would like to provide an common API on top of those interfaces. Each interface has a sample data type and a units for its data. So I'm representing a vector of samples from each device as a std::vector of Boost.Units quantities (i.e. std::vector<boost::units::quantity<unit,sample_type> >). I'd like to use a multi-cast style architecture, where each data source broadcasts newly received data to 1 or more interested parties. Qt's Signal/Slot mechanism is an obvious fit for this style. So, I'd like each data source to emit a signal like typedef std::vector<boost::units::quantity<unit,sample_type> > SampleVector signals: void samplesAcquired(SampleVector sampleVector); for the unit and sample_type appropriate for that device. Since tempalted QObject subclasses aren't supported by the meta-object compiler, there doesn't seem to be a way to have a (tempalted) base class for all data sources which defines the samplesAcquired Signal. In other words, the following won't work: template<T,U> //sample type and units class DataSource : public QObject { Q_OBJECT ... public: typedef std::vector<boost::units::quantity<U,T> > SampleVector signals: void samplesAcquired(SampleVector sampleVector); }; The best option I've been able to come up with is a two-layered approach: template<T,U> //sample type and units class IAcquiredSamples { public: typedef std::vector<boost::units::quantity<U,T> > SampleVector virtual shared_ptr<SampleVector> acquiredData(TimeStamp ts, unsigned long nsamples); }; class DataSource : public QObject { ... signals: void samplesAcquired(TimeStamp ts, unsigned long nsamples); }; The samplesAcquired signal now gives a timestamp and number of samples for the acquisition and clients must use the IAcquiredSamples API to retrieve those samples. Obviously data sources must subclass both DataSource and IAcquiredSamples. The disadvantage of this approach appears to be a loss of simplicity in the API... it would be much nicer if clients could get the acquired samples in the Slot connected. Being able to use Qt's queued connections would also make threading issues easier instead of having to manage them in the acquiredData method within each subclass. One other possibility, is to use a QVariant argument. This necessarily puts the onus on subclass to register their particular sample vector type with Q_REGISTER_METATYPE/qRegisterMetaType. Not really a big deal. Clients of the base class however, will have no way of knowing what type the QVariant value type is, unless a tag struct is also passed with the signal. I consider this solution at least as convoluted as the one above, as it forces clients of the abstract base class API to deal with some of the gnarlier aspects of type system. So, is there a way to achieve the templated signal parameter? Is there a better architecture than the one I've proposed?

  Read the article

• nTop RRD file architecture

  - by Seanny123

  I have a gig of nTop RRD files and I would like to start graphing them with rrdtool (but not with nTop, since I'm hoping to do this with a separate backup of the database as workaround to the impossibility of limiting the RRD files by size), but I don't know how the files are structured. I've tried reading the RRD documentation from SourceForge and the nTop FAQ, but I'm not finding the information I need. Does anyone know of any documentation I should be looking at or how the files are structured? Here https://dl.dropbox.com/u/669437/file%20structure.png is a screenshot of the file structure. At first I thought it was organized by IP address (so the rrd files for address 1.1.2.3 would be stored in folder 1-1-2-3 or even the reverse order), but that doesn't seem to be the case. It isn't organized by MAC address either, although some hosts are saved that way. Any help would be appreciated.

  Read the article

• Key components to take care of in an Email architecture

  - by SQL Baba

  What are key components to take care of in an inhouse or hosted email system? What configuration settings doea an administrator have to go through periodically?

  Read the article

• shared web hosting architecture in a university setting

  - by gaspol

  We're in the process of creating a shared webhosting infrastructure for our university. Departments within the university can host their sites on this infrastructure. We're thinking of setting up multiple, load balanced web servers attached to shared storage (for web content and Apache config files). There will also be database servers behind these web servers. Does anyone have any other suggestions about this? Any recommendations for an alternative setup? Would having cPanel/WHM/Plesk be a good idea to automate account creation/maintenance?

  Read the article

• 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.

  Read the article

• Online modelling tool for server desing / architecture

  - by 2ge

  I am looking for some online (the best is free) tool for designing our servers. We use almost 10 servers now, and it becoming mess, to remember, where, what service is running. So, I'd like to have some online modeling tool, where I can set up things like: - server host - server hw parameters - server os - server services with running programs I am looking for server designing tool like online SQL modeling on http://ondras.zarovi.cz/sql/demo/?keyword=default (WWW SQL designer) Any ideas ?

  Read the article

• Looking for a real-world example illustrating that composition can be superior to inheritance

  - by Job

  I watched a bunch of lectures on Clojure and functional programming by Rich Hickey as well as some of the SICP lectures, and I am sold on many concepts of functional programming. I incorporated some of them into my C# code at a previous job, and luckily it was easy to write C# code in a more functional style. At my new job we use Python and multiple inheritance is all the rage. My co-workers are very smart but they have to produce code fast given the nature of the company. I am learning both the tools and the codebase, but the architecture itself slows me down as well. I have not written the existing class hierarchy (neither would I be able to remember everything about it), and so, when I started adding a fairly small feature, I realized that I had to read a lot of code in the process. At the surface the code is neatly organized and split into small functions/methods and not copy-paste-repetitive, but the flip side of being not repetitive is that there is some magic functionality hidden somewhere in the hierarchy chain that magically glues things together and does work on my behalf, but it is very hard to find and follow. I had to fire up a profiler and run it through several examples and plot the execution graph as well as step through a debugger a few times, search the code for some substring and just read pages at the time. I am pretty sure that once I am done, my resulting code will be short and neatly organized, and yet not very readable. What I write feels declarative, as if I was writing an XML file that drives some other magic engine, except that there is no clear documentation on what the XML should look like and what the engine does except for the existing examples that I can read as well as the source code for the 'engine'. There has got to be a better way. IMO using composition over inheritance can help quite a bit. That way the computation will be linear rather than jumping all over the hierarchy tree. Whenever the functionality does not quite fit into an inheritance model, it will need to be mangled to fit in, or the entire inheritance hierarchy will need to be refactored/rebalanced, sort of like an unbalanced binary tree needs reshuffling from time to time in order to improve the average seek time. As I mentioned before, my co-workers are very smart; they just have been doing things a certain way and probably have an ability to hold a lot of unrelated crap in their head at once. I want to convince them to give composition and functional as opposed to OOP approach a try. To do that, I need to find some very good material. I do not think that a SCIP lecture or one by Rich Hickey will do - I am afraid it will be flagged down as too academic. Then, simple examples of Dog and Frog and AddressBook classes do not really connivence one way or the other - they show how inheritance can be converted to composition but not why it is truly and objectively better. What I am looking for is some real-world example of code that has been written with a lot of inheritance, then hit a wall and re-written in a different style that uses composition. Perhaps there is a blog or a chapter. I am looking for something that can summarize and illustrate the sort of pain that I am going through. I already have been throwing the phrase "composition over inheritance" around, but it was not received as enthusiastically as I had hoped. I do not want to be perceived as a new guy who likes to complain and bash existing code while looking for a perfect approach while not contributing fast enough. At the same time, my gut is convinced that inheritance is often the instrument of evil and I want to show a better way in a near future. Have you stumbled upon any great resources that can help me?

  Read the article

• Time Synch Architecture in Windows Domain Environment

  - by Param

  I just read the following article -- "In a domain, time synchronization takes place when Windows Time Service turns on during system startup and periodically while the system is running." ( http://technet.microsoft.com/en-us/library/cc779145%28v=ws.10%29.aspx ) From the above article i get to know that the first sync it take as soon as i start my system, but after that in how many minutes or second or in how many periodic interval my windows client ( Window XP, window7 or window server 2008 member ) synch with my Domain controller (PDC emulator )??? Do you have any idea, and how should i verify my synch time interval? My Domain Controller is Window server 2008 R2 Standard

  Read the article

• Sharp architecture; Accessing Validation Results

  - by nabeelfarid

  I am exploring Sharp Architecture and I would like to know how to access the validation results after calling Entity.IsValid(). I have two scenarios e.g. 1) If the entity.IsValid() return false, I would like to add the errors to ModelState.AddModelError() collection in my controller. E.g. in the Northwind sample we have an EmployeesController.Create() action when we do employee.IsValid(), how can I get access to the errors? public ActionResult Create(Employee employee) { if (ViewData.ModelState.IsValid && employee.IsValid()) { employeeRepository.SaveOrUpdate(employee); } // .... } [I already know that when an Action method is called, modelbinder enforces validation rules(nhibernate validator attributes) as it parses incoming values and tries to assign them to the model object and if it can't parse the incoming values  then it register those as errors in modelstate for each model object property. But what if i have some custom validation. Thats why we do ModelState.IsValid first.] 2) In my test methods I would like to test the nhibernate validation rules as well. I can do entity.IsValid() but that only returns true/ false. I would like to Assert against the actual error not just true/ false. In my previous projects, I normally use a wrapper Service Layer for Repositories, and instead of calling Repositories method directly from controller, controllers call service layer methods which in turn call repository methods. In my Service Layer all my custom validation rules resides and Service Layer methods throws a custom exception with a NameValueCollection of errors which I can easily add to ModelState in my controller. This way I can also easily implement sophisticated business rules in my service layer as well. I kow sharp architecture also provides a Service Layer project. But what I am interested in and my next question is: How I can use NHibernate Vaidators to implement sophisticated custom business rules (not just null,empty, range etc.) and make Entity.IsValid() to verify those rules too ?

  Read the article

• Python libusb pyusb "mach-o, but wrong architecture"

  - by Jon

  I am having some trouble with the pyusb module. I have narrowed down the problem to a single line, and have created a small example script to replicate the error. #!/usr/bin/env python """ This module was created to isolate the problem in the pyusb package. Operating system: Mac OS 10.6.3 Python Version: 2.6.4 libusb 1.0.8 has been successfully installed using: sudo port install libusb I have also tried modifying /opt/local/etc/macports/macports.conf to force the i386 architecture instead of x86_64. """ from ctypes import * import ctypes.util libname = ctypes.util.find_library('usb-1.0') print 'libname: ', libname l = CDLL(libname, RTLD_GLOBAL) # RESULT: #libname: /usr/local/lib/libusb-1.0.dylib #Traceback (most recent call last): # File "./pyusb_problem.py", line 7, in <module> # l = CDLL(libname, RTLD_GLOBAL) # File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/ctypes/__init__.py", line 353, in __init__ # self._handle = _dlopen(self._name, mode) #OSError: dlopen(/usr/local/lib/libusb-1.0.dylib, 10): no suitable image found. Did find: # /usr/local/lib/libusb-1.0.dylib: mach-o, but wrong architecture # End of File This same script runs on Ubuntu 10.04 successfully. I have tried building the libusb module (directly from source AND through macports) for 32-bit (i386) instead of x86_64 (default for OS 10.6), but I receive the same error. Thank-you in advance for your help!

  Read the article

• sharp architecture question

  - by csetzkorn

  I am trying to get my head around the sharp architecture and follow the tutorial. I am using this code: using Bla.Core; using System.Collections.Generic; using Bla.Core.DataInterfaces; using System.Web.Mvc; using SharpArch.Core; using SharpArch.Web; using Bla.Web; namespace Bla.Web.Controllers { public class UsersController { public UsersController(IUserRepository userRepository) { Check.Require(userRepository != null,"userRepository may not be null"); this.userRepository = userRepository; } public ActionResult ListStaffMembersMatching(string filter) { List<User> matchingUsers = userRepository.FindAllMatching(filter); return View("ListUsersMatchingFilter", matchingUsers); } private readonly IUserRepository userRepository; } } I get this error: The name 'View' does not exist in the current context I have used all the correct using statements and referenced the assemblies as far as I can see. The views live in Bla.Web in this architecture. Can anyone see the problem? Thanks. Christian

  Read the article

• Architecture for data layer that uses both localStorage and a REST remote server

  - by Zack

  Anybody has any ideas or references on how to implement a data persistence layer that uses both a localStorage and a REST remote storage: The data of a certain client is stored with localStorage (using an ember-data indexedDB adapter). The locally stored data is synced with the remote server (using ember-data RESTadapter). The server gathers all data from clients. Using mathematical sets notation: Server = Client1 ? Client2 ? ... ? ClientN where, in general, a record may not be unique to a certain client. Here are some scenarios: A client creates a record. The id of the record can not set on the client, since it may conflict with a record stored on the server. Therefore a newly created record needs to be committed to the server - receive the id - create the record in localStorage. A record is updated on the server, and as a consequence the data in localStorage and in the server go out of sync. Only the server knows that, so the architecture needs to implement a push architecture (?) Would you use 2 stores (one for localStorage, one for REST) and sync between them, or use a hybrid indexedDB/REST adapter and write the sync code within the adapter? Can you see any way to avoid implementing push (Web Sockets, ...)?

  Read the article

• Web application architecture, and application servers?

  - by seanieb

  Hi, I'm building a web application, and I need to use an architecture that allows me to run it on two servers. The application scrapes information from other sites periodically, and on input from the end user. To do this I'm using Php+curl to scrape the information, Php or python to parse it and store the results in a MySQLDB. Then I will use Python to run some algorithms on the data, this will happen both periodically and on input from the end user. I'm going to cache some of the results in the MySQL DB and sometimes if it is specific to the user, skip storing the data and serve it to the user. I'm think of using Php for the website front end on a separate web server, running the Php spider, MySQL DB and python on another server. As you can see I'm fairly clueless. I'm familiar with using Php, MySQL and the basics of Python, but bringing this all together using something more complex than a cron job is new to me. How do go about implementing this? What frame work(s) should I use? Is MVC a good architecture for this? (I'm new to MVC, architectures etc.) Is Cakephp a good solution? If so will I be able to control and monitor the Python code using it?

  Read the article

• make arm architecture c library in mac

  - by gamegamelife

  I'm trying to make my own c library in Mac and include it to my iphone program. The c code is simple , like this: math.h: int myPow2(int); math.c: #include "math.h" int myPow2(int num) { return num*num; } I search how to make the c library file ( .a or .lib ..etc) seems need to use gcc compiler (Is there other methods?) so I use this command: gcc -c math.c -o math.o ar rcs libmath.a math.o And include it in iPhone Project. Now it has the problem when build xcode iphone project. "file was built for unsupported file format which is not the architecture being linked" I found some pages discuss about the problem, but no detail how to make the i386/arm architecture library. And I finally use this command to do it: gcc -arch i386 -c math.c -o math.o /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-gcc-4.2.1 -c math.c -o math.o I dont know if this method is correct? Or there has another method to do it?

  Read the article

• Declarative Architectures in Infrastructure as a Service (IaaS)

  - by BuckWoody

  I deal with computing architectures by first laying out requirements, and then laying in any constraints for it's success. Only then do I bring in computing elements to apply to the system. As an example, a requirement might be "world-side availability" and a constraint might be "with less than 80ms response time and full HA" or something similar. Then I can choose from the best fit of technologies which range from full-up on-premises computing to IaaS, PaaS or SaaS. I also deal in abstraction layers - on-premises systems are fully under your control, in IaaS the hardware is abstracted (but not the OS, scale, runtimes and so on), in PaaS the hardware and the OS is abstracted and you focus on code and data only, and in SaaS everything is abstracted - you merely purchase the function you want (like an e-mail server or some such) and simply use it. When you think about solutions this way, the architecture moves to the primary factor in your decision. It's problem-first architecting, and then laying in whatever technology or vendor best fixes the problem. To that end, most architects design a solution using a graphical tool (I use Visio) and then creating documents that  let the rest of the team (and business) know what is required. It's the template, or recipe, for the solution. This is extremely easy to do for SaaS - you merely point out what the needs are, research the vendor and present the findings (and bill) to the business. IT might not even be involved there. In PaaS it's not much more complicated - you use the same Application Lifecycle Management and design tools you always have for code, such as Visual Studio or some other process and toolset, and you can "stamp out" the application in multiple locations, update it and so on. IaaS is another story. Here you have multiple machines, operating systems, patches, virus scanning, run-times, scale-patterns and tools and much more that you have to deal with, since essentially it's just an in-house system being hosted by someone else. You can certainly automate builds of servers - we do this as technical professionals every day. From Windows to Linux, it's simple enough to create a "build script" that makes a system just like the one we made yesterday. What is more problematic is being able to tie those systems together in a coherent way (as a solution) and then stamp that out repeatedly, especially when you might want to deploy that solution on-premises, or in one cloud vendor or another. Lately I've been working with a company called RightScale that does exactly this. I'll point you to their site for more info, but the general idea is that you document out your intent for a set of servers, and it will deploy them to on-premises clouds, Windows Azure, and other cloud providers all from the same script. In other words, it doesn't contain the images or anything like that - it contains the scripts to build them on-premises or on a cloud vendor like Microsoft. Using a tool like this, you combine the steps of designing a system (all the way down to passwords and accounts if you wish) and then the document drives the distribution and implementation of that intent. As time goes on and more and more companies implement solutions on various providers (perhaps for HA and DR) then this becomes a compelling investigation. The RightScale information is here, if you want to investigate it further. Yes, there are other methods I've found, but most are tied to a single kind of cloud, and I'm not into vendor lock-in. Poppa Bear Level - Hands-on EvaluateRightScale at no cost.  Just bring your Windows Azurecredentials and follow the these tutorials: Sign Up for Windows Azure Add     Windows Azure to a RightScale Account Windows Azure Virtual Machines     3-tier Deployment Momma Bear Level - Just the Right level... ;0)  WindowsAzure Evaluation Guide - if you are new toWindows Azure Virtual Machines and new to RightScale, we recommend that youread the entire evaluation guide to gain a more complete understanding of theWindows Azure + RightScale solution.    WindowsAzure Support Page @ support.rightscale.com - FAQ's, tutorials,etc. for  Windows Azure Virtual Machines (Work in Progress) Baby Bear Level - Marketing WindowsAzure Page @ www.rightscale.com - find overview informationincluding solution briefs and presentation & demonstration videos   Scale     and Automate Applications on Windows Azure  Solution Brief     - how RightScale makes Windows Azure Virtual Machine even better SQL     Server on Windows Azure  Solution Brief   -       Run Highly Available SQL Server on Windows Azure Virtual Machines

  Read the article

• High Availability for IaaS, PaaS and SaaS in the Cloud

  - by BuckWoody

  Outages, natural disasters and unforeseen events have proved that even in a distributed architecture, you need to plan for High Availability (HA). In this entry I'll explain a few considerations for HA within Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). In a separate post I'll talk more about Disaster Recovery (DR), since each paradigm has a different way to handle that. Planning for HA in IaaS IaaS involves Virtual Machines - so in effect, an HA strategy here takes on many of the same characteristics as it would on-premises. The primary difference is that the vendor controls the hardware, so you need to verify what they do for things like local redundancy and so on from the hardware perspective. As far as what you can control and plan for, the primary factors fall into three areas: multiple instances, geographical dispersion and task-switching. In almost every cloud vendor I've studied, to ensure your application will be protected by any level of HA, you need to have at least two of the Instances (VM's) running. This makes sense, but you might assume that the vendor just takes care of that for you - they don't. If a single VM goes down (for whatever reason) then the access to it is lost. Depending on multiple factors, you might be able to recover the data, but you should assume that you can't. You should keep a sync to another location (perhaps the vendor's storage system in another geographic datacenter or to a local location) to ensure you can continue to serve your clients. You'll also need to host the same VM's in another geographical location. Everything from a vendor outage to a network path problem could prevent your users from reaching the system, so you need to have multiple locations to handle this. This means that you'll have to figure out how to manage state between the geo's. If the system goes down in the middle of a transaction, you need to figure out what part of the process the system was in, and then re-create or transfer that state to the second set of systems. If you didn't write the software yourself, this is non-trivial. You'll also need a manual or automatic process to detect the failure and re-route the traffic to your secondary location. You could flip a DNS entry (if your application can tolerate that) or invoke another process to alias the first system to the second, such as load-balancing and so on. There are many options, but all of them involve coding the state into the application layer. If you've simply moved a state-ful application to VM's, you may not be able to easily implement an HA solution. Planning for HA in PaaS Implementing HA in PaaS is a bit simpler, since it's built on the concept of stateless applications deployment. Once again, you need at least two copies of each element in the solution (web roles, worker roles, etc.) to remain available in a single datacenter. Also, you need to deploy the application again in a separate geo, but the advantage here is that you could work out a "shared storage" model such that state is auto-balanced across the world. In fact, you don't have to maintain a "DR" site, the alternate location can be live and serving clients, and only take on extra load if the other site is not available. In Windows Azure, you can use the Traffic Manager service top route the requests as a type of auto balancer. Even with these benefits, I recommend a second backup of storage in another geographic location. Storage is inexpensive; and that second copy can be used for not only HA but DR. Planning for HA in SaaS In Software-as-a-Service (such as Office 365, or Hadoop in Windows Azure) You have far less control over the HA solution, although you still maintain the responsibility to ensure you have it. Since each SaaS is different, check with the vendor on the solution for HA - and make sure you understand what they do and what you are responsible for. They may have no HA for that solution, or pin it to a particular geo, or perhaps they have a massive HA built in with automatic load balancing (which is often the case).   All of these options (with the exception of SaaS) involve higher costs for the design. Do not sacrifice reliability for cost - that will always cost you more in the end. Build in the redundancy and HA at the very outset of the project - if you try to tack it on later in the process the business will push back and potentially not implement HA. References: http://www.bing.com/search?q=windows+azure+High+Availability  (each type of implementation is different, so I'm routing you to a search on the topic - look for the "Patterns and Practices" results for the area in Azure you're interested in)

  Read the article

• SOA, Governance, and Drugs

  Why is IT governance important in service oriented architecture (SOA)? IT Governance provides a framework for making appropriate decisions based on company guidelines and accepted standards. This framework also outlines each stakeholder’s responsibilities and authority when making important architectural or design decisions. Furthermore, this framework of governance defines parameters and constraints that are used to give context and perspective when making decisions. The use of governance as it applies to SOA ensures that specific design principles and patterns are used when developing and maintaining services. When governance is consistently applied systems the following benefits are achieved according to Anne Thomas Manes in 2010. Governance makes sure that services conform to standard interface patterns, common data modeling practices, and promotes the incorporation of existing system functionality by building on top of other available services across a system. Governance defines development standards based on proven design principles and patterns that promote reuse and composition. Governance provides developers a set of proven design principles, standards and practices that promote the reduction in system based component dependencies.  By following these guidelines, individual components will be easier to maintain. For me personally, I am a fan of IT governance, and feel that it valuable part of any corporate IT department. However, depending on how it is implemented can really affect the value of using IT governance.  Companies need to find a way to ensure that governance does not become extreme in its policies and procedures. I know for me personally, I would really dislike working under a completely totalitarian or laissez-faire version of governance. Developers need to be able to be creative in their designs and too much governance can really impede the design process and prevent the most optimal design from being developed. On the other hand, with no governance enforced, no standards will be followed and accepted design patterns will be ignored. I have personally had to spend a lot of time working on this particular scenario and I have found that the concept of code reuse and composition is almost nonexistent.  Based on this, too much time and money is wasted on redeveloping existing aspects of an application that already exist within the system as a whole. I think moving forward we will see a staggered form of IT governance, regardless if it is for SOA or IT in general.  Depending on the size of a company and the size of its IT department,  I can see IT governance as a layered approach in that the top layer will be defined by enterprise architects that focus on abstract concepts pertaining to high level design, general  guidelines, acceptable best practices, and recommended design patterns.  The next layer will be defined by solution architects or department managers that further expand on abstracted guidelines defined by the enterprise architects. This layer will contain further definitions as to when various design patterns, coding standards, and best practices are to be applied based on the context of the solutions that are being developed by the department. The final layer will be defined by the system designer or a solutions architect assed to a project in that they will define what design patterns will be used in a solution, naming conventions, as well as outline how a system will function based on the best practices defined by the previous layers. This layered approach allows for IT departments to be flexible in that system designers have creative leeway in designing solutions to meet the needs of the business, but they must operate within the confines of the abstracted IT governance guidelines.  A real world example of this can be seen in the United States as it pertains to governance of the people in that the US government defines rules and regulations in the abstract and then the state governments take these guidelines and applies them based on the will of the people in each individual state. Furthermore, the county or city governments are the ones that actually enforce these rules based on how they are interpreted by local community.  To further define my example, the United States government defines that marijuana is illegal. Each individual state has the option to determine this regulation as it wishes in that the state of Florida determines that all uses of the drug are illegal, but the state of California legally allows the use of marijuana for medicinal purposes only. Based on these accepted practices each local government enforces these rules in that a police officer will arrest anyone in the state of Florida for having this drug on them if they walk down the street, but in California if a person has a medical prescription for the drug they will not get arrested.  REFERENCESThomas Manes, Anne. (2010). Understanding SOA Governance: http://www.soamag.com/I40/0610-2.php

  Read the article

• Facebook Game Development - .NET - Which architecture?

  - by Ben

  I am starting to develop a facebook game using ASP.NET + Silverlight Which architecture would you use? ASP.NET MVC or MVVM or RIA Services? ALso what do you think about using XNA with Silversprite? The game won't be a arcade game. It will be more strategy/RPG. Thanks a lot in advance.

  Read the article

• Can I upgrade to VS2010 Ultimate if I buy Visual Studio Team System 2008 Architecture Edition

  - by naveed

  If I were to buy Microsoft Visual Studio Team System 2008 Architecture Edition that includes MSDN Premium (UEF-00026), would I be upgraded to Visual 2010 Ultimate?

  Read the article

< Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34  | Next Page >