Search Results

Search found 16050 results on 642 pages for 'linq to objects'.

Page 572/642 | < Previous Page | 568 569 570 571 572 573 574 575 576 577 578 579  | Next Page >

• Enterprise Platform in Python, Design Advice

  - by Jason Miesionczek

  I am starting the design of a somewhat large enterprise platform in Python, and was wondering if you guys can give me some advice as to how to organize the various components and which packages would help achieve the goals of scalability, maintainability, and reliability. The system is basically a service that collects data from various outside sources, with each outside source having its own separate application. These applications would poll a central database and get any requests that have been submitted to perform on the external source. There will be a main website and REST/SOAP API that should also have access to the central data service. My initial thought was to use Django for the web site, web service and data access layer (using its built-in ORM), and then the outside source applications can use the web service(s) to get the information they need to process the request and save the results. Using this method would allow me to have multiple instances of the service applications running on the same or different machines to balance out the load. Are there more elegant means of accomplishing this? i've heard of messaging systems such as MQ, would something like that be beneficial in this scenario? My other thought was to use a completely separate data service not based on Django, and use some kind of remoting or remote objects (in they exist in Python) to interact with the data model. The downside here would be with the website which would become much slower if it had to push all of its data requests through a second layer. I would love to hear what other developers have come up with to achieve these goals in the most flexible way possible.

  Read the article

• How much is too much memory allocation in NDK?

  - by Maximus

  The NDK download page notes that, "Typical good candidates for the NDK are self-contained, CPU-intensive operations that don't allocate much memory, such as signal processing, physics simulation, and so on." I came from a C background and was excited to try to use the NDK to operate most of my OpenGL ES functions and any native functions related to physics, animation of vertices, etc... I'm finding that I'm relying quite a bit on Native code and wondering if I may be making some mistakes. I've had no trouble with testing at this point, but I'm curious if I may run into problems in the future. For example, I have game struct defined (somewhat like is seen in the San-Angeles example). I'm loading vertex information for objects dynamically (just what is needed for an active game area) so there's quite a bit of memory allocation happening for vertices, normals, texture coordinates, indices and texture graphic data... just to name the essentials. I'm quite careful about freeing what is allocated between game areas. Would I be safer setting some caps on array sizes or should I charge bravely forward as I'm going now?

  Read the article

• Best way reading from dirty excel sheets

  - by Ten Ton Gorilla

  I have to manipulate some Excel documents with C#. It's a batch process with no user interaction. It's going to parse data into a database, then output nice reports. The data is very dirty and cannot be ready using ADO. The data is nowhere near a nice table format. Best is defined as the most stable(updates less likely to break)/ clear(succinct) code. Fast doesn't matter. If it runs in less than 8 hours I'm fine. I have the logic to find the data worked out. All I need to make it run is basic cell navigation and getvalue type functions. Give me X cell value as string, if it matches Y value with levenshtein distance < 3, then give me Z cell value. My question is, what is the best way to dig into the excel? VSTO? Excel Objects Library? Third Option I'm not aware of?

  Read the article

• When is a try catch not a try catch?

  - by Dearmash

  I have a fun issue where during application shutdown, try / catch blocks are being seemingly ignored in the stack. I don't have a working test project (yet due to deadline, otherwise I'd totally try to repro this), but consider the following code snippet. public static string RunAndPossiblyThrow(int index, bool doThrow) { try { return Run(index); } catch(ApplicationException e) { if(doThrow) throw; } return ""; } public static string Run(int index) { if(_store.Contains(index)) return _store[index]; throw new ApplicationException("index not found"); } public static string RunAndIgnoreThrow(int index) { try { return Run(index); } catch(ApplicationException e) { } return ""; } During runtime this pattern works famously. We get legacy support for code that relies on exceptions for program control (bad) and we get to move forward and slowly remove exceptions used for program control. However, when shutting down our UI, we see an exception thrown from "Run" even though "doThrow" is false for ALL current uses of "RunAndPossiblyThrow". I've even gone so far as to verify this by modifying code to look like "RunAndIgnoreThrow" and I'll still get a crash post UI shutdown. Mr. Eric Lippert, I read your blog daily, I'd sure love to hear it's some known bug and I'm not going crazy. EDIT This is multi-threaded, and I've verified all objects are not modified while being accessed

  Read the article

• After calling a COM-dll component, C# exceptions are not caught by the debugger

  - by shlomil

  I'm using a COM dll provided to me by 3rd-party software company (I don't have the source code). I do know for sure they used Java to implement it because their objects contain property names like 'JvmVersion'. After I instantiated an object introduced by the provided COM dll, all exceptions in my C# program cannot be caught by the VS debugger and every time an exception occurs I get the default Windows Debugger Selection dialog (And that's while executing my program in debug mode under a full VisualStudio debugging environment). To illustrate: throw new Exception("exception 1"); m_moo = new moo(); // Component taken from the COM-dll throw new Exception("exception 2"); Exception 1 will be caught by VS and show the "yellow exception window". Exception 2 will open a dialog titled "Visual Studio Just-In-Time Debugger" containing the text "An unhandled win32 exception occurred in myfile.vshost.exe[1348]." followed by a list of the existing VS instances on my system to select from. I guess the instantiation of "moo" object overrides C#'s exception handler or something like that. Am I correct and is there a way to preserve C#'s exception handler?

  Read the article

• Issue with class design to model user preferences for different classes

  - by Mulone

  Hi all, I'm not sure how to design a couple of classes in my app. Basically that's a situation: each user can have many preferences each preference can be referred to an object of different classes (e.g. album, film, book etc) the preference is expressed as a set of values (e.g. score, etc). The problem is that many users can have preferences on the same objects, e.g.: John: score=5 for filmid=apocalypsenow Paul: score=3 for filmid=apocalypsenow And naturally I don't want to duplicate the object film in each user. So I could create a class called "preference" holding a score and then a target object, something like: User{ hasMany preferences } Preference{ belongsTo User double score Film target Album target //etc } and then define just one target. Then I would create an interface for the target Classes (album, film etc): Interface canBePreferred{ hasMany preferences } And implement all of those classes. This could work, but it looks pretty ugly and it would requires a lot of joins to work. Do you have some patterns I could use to model this nicely? Cheers, Mulone

  Read the article

• Flex Tree with infinite parents and children

  - by Tempname

  I am working on a tree component and I am having a bit of the issue with populating the data-provider for this tree. The data that I get back from my database is a simple array of value objects. Each value object has 2 properties. ObjectID and ParentID. For parents the ParentID is null and for children the ParentID is the ObjectID of the parent. Any help with this is greatly appreciated. Essentially the tree should look something like this: Parent1 Child1 Child1 Child2 Child1 Child2 Parent2 Child1 Child2 Child3 Child1 This is the current code that I am testing with: public function setDataProvider(data:Array):void { var tree:Array = new Array(); for(var i:Number = 0; i < data.length; i++) { // do the top level array if(!data[i].parentID) { tree.push(data[i], getChildren(data[i].objectID, data)); } } function getChildren(objectID:Number, data:Array):Array { var childArr:Array = new Array(); for(var k:Number = 0; k < data.length; k++) { if(data[k].parentID == objectID) { childArr.push(data[k]); //getChildren(data[k].objectID, data); } } return childArr; } trace(ObjectUtil.toString(tree)); } Here is a cross section of my data: ObjectID ParentID 1 NULL 10 NULL 8 NULL 6 NULL 4 6 3 6 9 6 2 6 11 7 7 8 5 8

  Read the article

• Bad idea to have the same object, have a different side effect after method call.

  - by Nathan W

  Hi all, I'm having a bit of a gesign issue(again). Say I have this Buttonpad object: now this object is a wrapper object over one in a com object. At the moment it has a method on it called CreateInto(IComObject). Now to make a new button pad in the Com Object. You do: ButtonPad pad = new ButtonPad(); pad.Title = "Hello"; // Set some more properties. pad.CreateInto(Cominstance); The createinfo method will excute the right commands to buid the button pad in the com object. After it has been created it any calls against it are foward to the underlying object for change so: pad.Title = "New title"; will call the com object to set the title and also set the internal title variable. Basically any calls before the CreateInfo method only affect the .NET object anything after has the side effect of calling the com object also. I'm not very good at sequence diagrams but here is my attempt to explain whats going on: This doesn't feel good to me, it feels like I'm lying to the user about what the button pad does. I was going to have a object called WrappedButtonPad, which is returned from CreateInto and the user could make calls against that to make changes to the Com Object, but I feel having two objects that almost do the same thing but only differ by names might be even worse. Are these valid designs, or am I right to be worried? How else would you handle a object the can create and query a com object?

  Read the article

• Effective communication in a component-based system

  - by Tesserex

  Yes, this is another question about my game engine, which is coming along very nicely, with much thanks to you guys. So, if you watched the video (or didn't), the objects in the game are composed of various components for things like position, sprites, movement, collision, sounds, health, etc. I have several message types defined for "tell" type communication between entities and components, but this only goes so far. There are plenty of times when I just need to ask for something, for example an entity's position. There are dozens of lines in my code that look like this: SomeComponent comp = (SomeComponent)entity.GetComponent(typeof(SomeComponent)); if (comp != null) comp.GetSomething(); I know this is very ugly, and I know that casting smells of improper OO design. But as complex as things are, there doesn't seem to be a better way. I could of course "hard-code" my component types and just have SomeComponent comp = entity.GetSomeComponent(); but that seems like a cop-out, and a bad one. I literally JUST REALIZED, while writing this, after having my code this way for months with no solution, that a generic will help me. SomeComponent comp = entity.GetComponent<SomeComponent>(); Amazing how that works. Anyway, this is still only a semantic improvement. My questions remain. Is this actually that bad? What's a better alternative?

  Read the article

• assembling an object graph without an ORM -- in the service layer or data layer?

  - by Hans Gruber

  At my current gig, our persistence layer uses IBatis going against SQL Server stored procedures (puke). IMHO, this approach has many disadvantages over the use of a "true" ORM such NHibernate or EF, but the one I'm trying to address here revolves around all the boilerplate code needed to map data from a result set into an object graph. Say I have the following DTO object graph I want to return to my presentation layer: IEnumerable<CustomerDTO> |--> IEnumerable<AddressDTO> |--> LatestOrderDTO The way I've implemented this is to have a discrete method in my DAO class to return each IEnumerable<*DTO>, and then have my service class be responsible for orchestrating the calls to the DAO. It then returns the fully assembled object graph to the client: public class SomeService(){ public SomeService(IDao someDao){ this._someDao = someDao; } public IEnumerable<CustomerDTO> ListCustomersForHistory(int brokerId){ var customers = _someDao.ListCustomersForBroker(brokerId); foreach (customer in customers){ customer.Addresses = someDao.ListCustomersAddresses(brokerId); customer.LatestOrder = someDao.GetCustomerLatestOrder(brokerId); } } return customers; } My question is should this logic belong in the service layer or the should I make my DAO such that it instead returns the assembled object graph. If I was using NHibernate, I assume that this kind of relationship association between objects comes for "free"?

  Read the article

• JPA returning null for deleted items from a set

  - by Jon

  This may be related to my question from a few days ago, but I'm not even sure how to explain this part. (It's an entirely different parent-child relationship.) In my interface, I have a set of attributes (Attribute) and valid values (ValidValue) for each one in a one-to-many relationship. In the Spring MVC frontend, I have a page for an administrator to edit these values. Once it's submitted, if any of these fields (as <input> tags) are blank, I remove the ValidValue object like so: Set<ValidValue> existingValues = new HashSet<ValidValue>(attribute.getValidValues()); Set<ValidValue> finalValues = new HashSet<ValidValue>(); for(ValidValue validValue : attribute.getValidValues()) { if(!validValue.getValue().isEmpty()) { finalValues.add(validValue); } } existingValues.removeAll(finalValues); for(ValidValue removedValue : existingValues) { getApplicationDataService().removeValidValue(removedValue); } attribute.setValidValues(finalValues); getApplicationDataService().modifyAttribute(attribute); The problem is that while the database is updated appropriately, the next time I query for the Attribute objects, they're returned with an extra entry in their ValidValue set -- a null, and thus, the next time I iterate through the values to display, it shows an extra blank value in the middle. I've confirmed that this happens at the point of a merge or find, at the point of "Execute query ReadObjectQuery(entity.Attribute). Here's the code I'm using to modify the database (in the ApplicationDataService): public void modifyAttribute(Attribute attribute) { getJpaTemplate().merge(attribute); } public void removeValidValue(ValidValue removedValue) { ValidValue merged = getJpaTemplate().merge(removedValue); getJpaTemplate().remove(merged); } Here are the relevant parts of the entity classes: Entity @Table(name = "attribute") public class Attribute { @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "attribute") private Set<ValidValue> validValues = new HashSet<ValidValue>(0); } @Entity @Table(name = "valid_value") public class ValidValue { @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "attr_id", nullable = false) private Attribute attribute; }

  Read the article

• Java generics question with wildcards

  - by Sean

  Just came across a place where I'd like to use generics and I'm not sure how to make it work the way I want. I have a method in my data layer that does a query and returns a list of objects. Here's the signature. public List getList(Class cls, Map query) This is what I'd like the calling code to look like. List<Whatever> list = getList(WhateverImpl.class, query); I'd like to make it so that I don't have to cast this to a List coming out, which leads me to this. public <T> List<T> getList(Class<T> cls, Map query) But now I have the problem that what I get out is always the concrete List<WhateverImpl> passed in whereas I'd like it to be the Whatever interface. I tried to use the super keyword but couldn't figure it out. Any generics gurus out there know how this can be done?

  Read the article

• Java constructor using generic types

  - by Beer Me

  I'm having a hard time wrapping my head around Java generic types. Here's a simple piece of code that in my mind should work, but I'm obviously doing something wrong. Eclipse reports this error in BreweryList.java: The method breweryMethod() is undefined for the type <T> The idea is to fill a Vector with instances of objects that are a subclass of the Brewery class, so the invocation would be something like: BreweryList breweryList = new BreweryList(BrewerySubClass.class, list); BreweryList.java package com.beerme.test; import java.util.Vector; public class BreweryList<T extends Brewery> extends Vector<T> { public BreweryList(Class<T> c, Object[] j) { super(); for (int i = 0; i < j.length; i++) { T item = c.newInstance(); // breweryMethod() is an instance method // of Brewery, of which <T> is a subclass (right?) c.breweryMethod(); // "The method breweryMethod() is undefined // for the type <T>" } } } Brewery.java package com.beerme.test; public class Brewery { public Brewery() { super(); } protected void breweryMethod() { } } BrewerySubClass.java package com.beerme.test; public class BrewerySubClass extends Brewery { public BrewerySubClass() { super(); } public void brewerySubClassMethod() { } } I'm sure this is a complete-generics-noob question, but I'm stuck. Thanks for any tips!

  Read the article

• What problem did MS solve by creating PowerShell? [closed]

  - by Fred

  I'm asking because PowerShell confuses me. I've been trying to write some deployment scripts using PowerShell and I've been less than enthused by the result. I have a co-worker who loves PowerShell and defends it at every turn. Said co-worker claims PowerShell was never written to be a strong shell, but instead was written to: a) Allow you to peek and poke at .NET assemblies on the command-line (why is this a reason for PowerShell to exist?) b) To be hosted in .NET applications for automation, similar to DCOP in KDE and how Gnome is using CORBA. c) to be treated as ".NET script" rather than as an actual shell (related to b). I've always felt like Windows was missing a decent way to bang out automation scripts. cmd is too simplistic in many cases, and WSH is too obtuse (although the combination can be used successfully, I'm not a fan). When I first heard about PowerShell I felt like Windows was finally getting a decent shell that would be able to help with automation of many tasks, but recent experiences, and my co-worker, tell me otherwise. To be clear, I don't take issue with the fact that it's built on .NET, or that it passes objects around rather than text (despite my Unix background :]), and I'm not arguing that PowerShell is useless, but from what I can see, it doesn't solve the problem I was hoping it would solve very well. As soon as you step outside of the .NET/Powershell world, things quit being nice and cozy for you. So with all that out of the way, what problem did MS solve by creating PowerShell, or is it some political bastard child as I suspect? I've googled and haven't hit upon anything that sufficiently answered that for me, but the more citations the better.

  Read the article

• best web database solution for scala for a high traffic site?

  - by egervari

  I am in charge of a rebuilding a website that gets about 250,000 visitors a day. We'd like to use Scala, but it does not work very well with Spring (in some minor cases) and Hibernate (there is a major and very annoying mismatch here if you want to use scala collections, which we do). The application itself is going to have about 40-50 tables. Other than Hibernate, is there an ORM that works awesome with Scala and is as performant and reliable as Hibernate? Does it also have the same capabilities, or are we going to run into leaky-abstractions if we don't use Hibernate? It would be a big risk for us to go with a framework that is newer and doesn't seem to have a lot of industry backing... and at the same time, Hibernate is a real pain to program against when using Scala. 1) The Java Collection <- Scala Collection is absolutely painful. There is a lot more boilerplate and crap to write. 2) The IDE doesn't import JavaConversions and java interfaces automatically... so we this needs to be done manually. Optimizing Imports in IDEA is going to destroy all the manual work. 3) There is also a performance cost to converting back and forth all the time in your domain objects and your dao classes. 4) Not to mention there needs to be a lot of casting, which produces code ugly as sin. I actually would love to write my own orm that is 100% tailored to scala, but obviously this is really outside of the scope of our project for now. So what is the best approach?

  Read the article

• In perl, how can I call a method whose name I have in a string?

  - by Ryan Thompson

  I'm trying to write some abstract code for searching through a list of similar objects for the first one whose attributes match specific values. In order to do this, I need to call a bunch of accessor methods and check all their values one by one. I'd like to use an abstraction like this: sub verify_attribute { my ($object, $attribute_method, $wanted_value) = @_; if ( call_method($object, $attribute_method) ~~ $wanted_value ) { return 1; } else { return; } } Then I can loop through a hash whose keys are accessor method names and whose values are the values I'm looking for for those attributes. For example, if that hash is called %wanted, I might use code like this to find the object I want: my $found_object; FINDOBJ: foreach my $obj (@list_of_objects) { foreach my $accessor (keys %wanted) { next FINDOBJ unless verify_attribute($obj, $accessor, $wanted{$accessor}); } # All attrs verified $found_object = $obj; last FINDOBJ; } Of course, the only problem is that call_method does not exsit. Or does it? How can I call a method if I have a string containing its name? Or is there a better solution to this whole problem?

  Read the article

• object.valid? returns false but object.errors.full_messages is empty

  - by user549563

  Hello I'm confuse about objects that I can't save, simplified model is class Subscription < ActiveRecord::base belongs_to :user, :class_name => "User", :foreign_key => "user_id" has_many :transactions, :class_name => "SubscriptionTransaction" validates_presence_of :first_name, :message => "ne peut être vide" validates_presence_of :last_name, :message => "ne peut être vide" validates_presence_of :card_number, :message => "ne peut être vide" validates_presence_of :card_verification, :message => "ne peut être vide" validates_presence_of :card_type, :message => "ne peut être vide" validates_presence_of :card_expires_on, :message => "ne peut être vide" attr_accessor :card_number, :card_verification validate_on_create :validate_card def validate_card unless credit_card.valid? credit_card.errors.full_messages.each do |message| errors.add_to_base message end end end def credit_card @credit_card ||= ActiveMerchant::Billing::CreditCard.new( :type => card_type, :number => card_number, :verification_value => card_verification, :month => card_expires_on.month, :year => card_expires_on.year, :first_name => first_name, :last_name => last_name ) end end and in my subscription_controller if subscription.save # do something else debugger # means breakpoint where i try subscription.errors.full_messages # do something else end I tried to use ruby-debug for this adding a breakpoint before. And subscription.valid? return false which explains that ActiveRecord doesn't allow the save method. Unfortunately i can't know why the object is invalid. subscription.errors.full_messages # => [] I'm stucked, if you have any idea, thank you.

  Read the article

• How to check at runtime if a class implements certain interface?

  - by mare

  Let's say I have some content classes like Page, TabGroup, Tab, etc. Certain of those will be implementing my IWidgetContainer interface - it means they will geet an additional field named ContainedItems from the interface and some methods for manipulating this field. Now I need to reflect the fact that some class implements this interface by rendering out some special custom controls in my ASP.NET MVC Views (like jQuery Add/Remove/Move/Reorder buttons). For instance, TabGroup will implement IWidgetContainer because it will contain tabs but a tab will not implement it because it won't have the ability to contain anything. So I have to somehow check in my view, when I render my content objects (The problem is, I use my base class as strong type in my view not concrete classes), whether it implements IWidgetContainer. How is that possible or have I completely missed something? To rephrase the question, how do you reflect some special properties of a class (like interface implementation) in the UI in general (not necessarily ASP.NET MVC)? Here's my code so far: [DataContract] public class ContentClass { [DataMember] public string Slug; [DataMember] public string Title; [DataMember] protected ContentType Type; } [DataContract] public class Group : ContentClass, IWidgetContainer { public Group() { Type = ContentType.TabGroup; } public ContentList ContainedItems { get; set; } public void AddContent(ContentListItem toAdd) { throw new NotImplementedException(); } public void RemoveContent(ContentListItem toRemove) { throw new NotImplementedException(); } } [DataContract] public class GroupElement : ContentClass { public GroupElement() { Type = ContentType.Tab; } } Interface: interface IWidgetContainer { [DataMember] ContentList ContainedItems { get; set; } void AddContent(ContentListItem toAdd); void RemoveContent(ContentListItem toRemove); }

  Read the article

• NHibernate: What are child sessions and why and when should I use them?

  - by stefando

  In the comments for the ayende's blog about the auditing in NHibernate there is a mention about the need to use a child session:session.GetSession(EntityMode.Poco). As far as I understand it, it has something to do with the order of the SQL operation which session.Flush will emit. (For example: If I wanted to perform some delete operation in the pre-insert event but the session was already done with deleting operations, I would need some way to inject them in.) However I did not find documentation about this feature and behavior. Questions: Is my understanding of child sessions correct? How and in which scenarios should I use them? Are they documented somewhere? Could they be used for session "scoping"? (For example: I open the master session which will hold some data and then I create 2 child-sessions from the master one. I'd expect that the two child-scopes will be separated but the will share objects from the master session cache. Is this the case?) Are they first class citizens in NHibernate or are they just hack to support some edge-case scenarios? Thanks in advance for any info.

  Read the article

• Populate two column grid with databinding?

  - by Richard

  How do i populate a two column grid with objects from my observable collection? I've tried to achieve this effect by using the tookits wrap panel but the items just stack. <toolkit:WrapPanel Margin="5,0,0,0" Width="400"> <ItemsControl ItemsSource="{Binding Trips}"> <ItemsControl.ItemTemplate> <DataTemplate> <StackPanel Height="236" Width="182"> <Button Style="{StaticResource VasttrafikButtonTrip}"> <StackPanel Width="152" Height="140"> <TextBlock Text="{Binding FromName}" /> <TextBlock FontFamily="Segoe WP Semibold" Text="till" /> <TextBlock Text="{Binding ToName}" /> </StackPanel> </Button> <TextBlock HorizontalAlignment="Left" Width="160" FontSize="16" FontWeight="ExtraBlack" Text="{Binding TravelTimeText}" /> <TextBlock HorizontalAlignment="Left" Width="160" Margin="0,-6,0,0" FontSize="16" Text="{Binding TransferCountText}" /> </StackPanel> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> </toolkit:WrapPanel>

  Read the article

• Valid javascript object property names

  - by hawkettc

  I'm trying to work out what is considered valid for the property name of a javascript object. For example var b = {} b['-^colour'] = "blue"; // Works fine in Firefox, Chrome, Safari b['colour'] = "green"; // Ditto alert(b['-^colour']); // Ditto alert(b.colour); // Ditto for(prop in b) alert(prop); // Ditto //alert(b.-^colour); // Fails (expected) This post details valid javascript variable names, and '-^colour' is clearly not valid (as a variable name). Does the same apply to object property names? Looking at the above I'm trying to work out if b['-^colour'] is invalid, but works in all browsers by quirk, and I shouldn't trust it to work going forward b['-^colour'] is completely valid, but it's just of a form that can only be accessed in this manner - (it's supported so Objects can be used as maps perhaps?) Something else As an aside, a global variable in javascript might be declared at the top level as var abc = 0; but could also be created (as I understand it) with window['abc'] = 0; the following works in all the above browsers window['@£$%'] = "bling!"; alert(window['@£$%']); Is this valid? It seems to contradict the variable naming rules - or am I not declaring a variable there? What's the difference between a variable and an object property name? Cheers, Colin

  Read the article

• Django throws 404 at generic views

  - by x0rg

  I'm trying to get the generic views for a date-based archive working in django. I defined the urls as described in a tutorial, but django returns a 404 error whenever I want to access an url with a variable (such as month or year) in it. It don't even produces a TemplateDoesNotExist-execption. Normal urls without variables work fine. Here's my urlconf: from django.conf.urls.defaults import * from zurichlive.zhl.models import Event info_dict = { 'queryset': Event.objects.all(), 'date_field': 'date', 'allow_future': 'True', } urlpatterns += patterns('django.views.generic.date_based', (r'events/(?P<year>d{4})/(?P<month>[a-z]{3})/(?P<day>w{1,2})/(?P<slug>[-w]+)/$', 'object_detail', dict(info_dict, slug_field='slug',template_name='archive/detail.html')), (r'^events/(?P<year>d{4})/(?P<month>[a-z]{3})/(?P<day>w{1,2})/(?P<slug>[-w]+)/$', 'object_detail', dict(info_dict, template_name='archive/list.html')), (r'^events/(?P<year>d{4})/(?P<month>[a-z]{3})/(?P<day>w{1,2})/$','archive_day',dict(info_dict,template_name='archive/list.html')), (r'^events/(?P<year>d{4})/(?P<month>[a-z]{3})/$','archive_month', dict(info_dict, template_name='archive/list.html')), (r'^events/(?P<year>)/$','archive_year', dict(info_dict, template_name='archive/list.html')), (r'^events/$','archive_index', dict(info_dict, template_name='archive/list.html')), ) When I access /events/2010/may/12/this-is-a-slug I should get to the detail.html template, but instead I get a 404. What am I doing wrong?

  Read the article

• Can Haskell's monads be thought of as using and returning a hidden state parameter?

  - by AJM

  I don't understand the exact algebra and theory behind Haskell's monads. However, when I think about functional programming in general I get the impression that state would be modelled by taking an initial state and generating a copy of it to represent the next state. This is like when one list is appended to another; neither list gets modified, but a third list is created and returned. Is it therefore valid to think of monadic operations as implicitly taking an initial state object as a parameter and implicitly returning a final state object? These state objects would be hidden so that the programmer doesn't have to worry about them and to control how they gets accessed. So, the programmer would not try to copy the object representing the IO stream as it was ten minutes ago. In other words, if we have this code: main = do putStrLn "Enter your name:" name <- getLine putStrLn ( "Hello " ++ name ) ...is it OK to think of the IO monad and the "do" syntax as representing this style of code? putStrLn :: IOState -> String -> IOState getLine :: IOState -> (IOState, String) main :: IOState -> IOState -- main returns an IOState we can call "state3" main state0 = putStrLn state2 ("Hello " ++ name) where (state2, name) = getLine state1 state1 = putStrLn state0 "Enter your name:"

  Read the article

• What is the best way to remove flickering from a fast series of image loads in Flash?

  - by msandbot

  Hi, working on making a flash program that loads about 1000 jpegs and then plays them like a movie. Have all the buttons and stuff working but the time it takes for an image to load is so high that the movie can't be played at 30 fps. I've tried multiple ways of fixing this using 1 scrollpane and changing its source ever 30 ms. This one is the worst but simplest. Flickers cause strobing and it is unwatchable. used 2 scrollpanes that were duplicates of each other until I had to load. I would then make that one invisible, load it , then make it visible. Then load the background one. Works but same problem as the first at high speeds, just less severe. used 1 scrollpane per image . This works great, except that it fails miserably on any more than 100 of them due to the number of objects. Has anyone else experienced/solved/wants to help me solve this? None of my fixes have worked. Currently using action script 3, but will change if its not possible in that. Also, I want to be able to zoom in and then scroll around the window hence the scrollpanes, but if that's not possible its a sacrifice I'm willing to make

  Read the article

• Scalability 101: How can I design a scalable web application using PHP?

  - by Legend

  I am building a web-application and have a couple of quick questions. From what I learnt, one should not worry about scalability when initially building the app and should only start worrying when the traffic increases. However, this being my first web-application, I am not quite sure if I should take an approach where I design things in an ad-hoc manner and later "fix" them. I have been reading stories about how people start off with an app that gets millions of users in a week or two. Not that I will face the same situation but I can't help but wonder, how do these people do it? Currently, I bought a shared hosting account on Lunarpages and that got me started in building and testing the application. However, I am interested in learning how to build the same application in a scalable-manner using the cloud, for instance, Amazon's EC2. From my understanding, I can see a couple of components: There is a load balancer that first receives requests and then decides where to route each request This request is then handled by a server replica that then processes the request and updates (if required) the database and sends back the response to the client If a similar request comes in, then a caching mechanism like memcached kicks into picture and returns objects from the cache A blackbox that handles database replication Specifically, I am trying to do the following: Setting up a load balancer (my homework revealed that HAProxy is one such load balancer) Setting up replication so that databases can be synchronized Using memcached Configuring Apache to work with multiple web servers Partitioning application to use Amazon EC2 and Amazon S3 (my application is something that will need great deal of storage) Finally, how can I avoid burning myself when using Amazon services? Because this is just a learning phase, I can probably do with 2-3 servers with a simple load balancer and replication but until I want to avoid paying loads of money accidentally. I am able to find resources on individual topics but am unable to find something that starts off from the big picture. Can someone please help me get started?

  Read the article

< Previous Page | 568 569 570 571 572 573 574 575 576 577 578 579  | Next Page >