I have recently started a working on my first project using the ABP Framework
I am implementing it as a module with no UI.
I would like to use Hangfire for recurring tasks, having advantage of the Hangfire UI/Dashboard that comes with it.
There is currently no documentation on Hangfire integration. The documentation page is empty. I understand ABP is relatively new, but I imagine someone has implemented it correctly.
The best I could find so far are Github issues(some of them still open) where users are trying to do the same.
Configuring Hangfire as Background Job Manager #2166
Use Volo.Abp.Hangfire Module ERROR #1313
I also noticed that there are two ABP Nuget packages for Hangfire:
Volo.Abp.HangFire
Volo.Abp.BackgroundJobs.HangFire
So my two main questions are:
By ABP convention, is it correct to implement the Hangfire job in my Name.Space.Domain project?
How do implement it as a recurring job?
In the mean time, I will patch up what I have drawn from the links I have shared and will happily share my solution if it works.
For the first question, it is totally fine to implement the business logic in the domain layer. Hence the Hangfire could handle some business logic.
For the second question, you can add this code in Configure function in start up:
app.UseHangfireDashboard();
app.UseHangfireServer();
RecurringJob.AddOrUpdate<yourjobsclass>(x => x.yourJobFunction, Cron.MinuteInterval(5));
Below are some resources that I think could help:
ASP.NET Core Applications: https://docs.hangfire.io/en/latest/getting-started/aspnet-core-applications.html
ASP.NET Applications: https://docs.hangfire.io/en/latest/getting-started/aspnet-applications.html
Related
I am constructing a web service that receives data and updates it periodically. When a user pings the service, it will send specific data back to the user. In order to receive this data, I have a persistent that is created on startup and regularly receives updates, but not at periodic intervals. I have already implemented it, but I would like to add DI and make it into a service. Can this type of problem be solved with a BackgroundService or is this not recommended? Is there anything better I should use? I originally wanted to just register my connection object as a singleton, but since singletons are not initialized on startup, that does not work so well for me.
I thought I would add an answer as so expand on my comment. From what you have described, creating a BackgroundService is likely the best solution for what you want to do.
ASP.NET Core provides an IHostedService interface that can be used to implement a background task or service, in your web app. They also provide a BackgroundService class that implements IHostedService and provides a base class for implementing long running background services. These background services are registered within the CreateWebHostBuilder method in Program.cs.
You can consume services from the dependency injection container but you will have to properly manage their scopes when using them. You can decide how to manage your BackgroundService classes in order to fit your needs. It does take an understanding of how to work with Task objects and executing, queueing, monitoring them etc. So I'd recommend giving the docs a thorough read, so you don't end up impacting performance or resource usage.
I also tend to use Autofac as my DI container rather than the built in Microsoft container, since Autofac provides more features for resolving services and managing scopes. So it's worth considering if you find yourself hitting a wall because of the built in container.
Here's the link to the docs section covering this in much more depth. I believe you can also create standalone service workers now, so that might be worth a look depending on use case.
https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/hosted-services?view=aspnetcore-3.1&tabs=visual-studio
Edit: Here's another link to a guide an example implementation for a microservice background service. It goes a little more in depth on some of the specifics.
https://learn.microsoft.com/en-us/dotnet/architecture/microservices/multi-container-microservice-net-applications/background-tasks-with-ihostedservice#implementing-ihostedservice-with-a-custom-hosted-service-class-deriving-from-the-backgroundservice-base-class
I'm creating a new application in Zend Framework 3 and i have a question about a design pattern
Without entering in much details this application will have several Services, as in, will be connecting to external APIs and even in multiple databases, the workflow is also very complex, a single will action can have multiple flows depending on several external information (wich user logged in, configs, etc).
I know about dependency injections and Zend Framework 3 Service Manager, however i am worried about instanciating sereval services when the flow will actually use only a few of them in certain cases, also we will have services depending on other services aswell, for this, i was thinking about using singletons.
Is singleton really a solution here? I was looking a way to user singletons in Zend Framework 3 and haven't figured out a easy way since i can't find a way to user the Service Manager inside a service, as I can't retrive the instance of the Service Manager outside of the Factory system.
What is an easy way to implement singletons in Zend Framework 3?
Why use singletons?
You don't need to worry about too many services in your service manager since they are started only when you get them from the service manager.
Also don't use the service manager inside another class except a factory. In ZF3 it's removed from the controllers for a reason. One of them is testability. If all services are inject with a factory, you can easily write tests. Also if you read your code next year, you can easily see what dependencies are needed inside a class.
If you find there are too many services being injected inside a class which are not always needed you can:
Use the ProxyManager. This lazy loads a service but doesn't start it until a method is called.
Split the service: Move some parts from a service into a new service. e.g. You don't need to place everything in an UserService. You can also have an UserRegisterService, UserEmailService, UserAuthService and UserNotificationsService.
In stead of ZF3, you can also think about zend-expressive. Without getting into too much detail, it is a lightweight middleware framework. You can use middleware to detect what is needed for a request and route to the required action to process the request. Something like this can probably also done in ZF3 but maybe someone else can explain how to do it there.
I'm building an Ember application with ember-cli and, as a persistence layer, an HTTP API using rails-api + Grape + ActiveModelSerializer. I am at a very basic stage but I want to setup my front-end and back-end in as much standard and clean way as possible before going on with developing further API and ember models.
I could not find a comprensive guide about serialization and deserialization made by the store but I read the documentation about DS.ActiveModelSerializer and DS.ActiveModelAdapter (which says the same things!) along with their parent classes.
What are the exact roles of adapter and serializer and how are they related?
Considering the tools I am using do I need to implement both of them?
Both Grape/ActiveModelSerializer and EmberData offer customization. As my back-end and front-end are for each other and not for anything else which side is it better to customize?
Hmmm...which side is better is subjective, so this is sort of my thought process:
Generally speaking, one would want an API that is able to "talk to anything" in case a device client is required or in case the API gets to be consumed by other parties in the future, so that would suggest that you'd config your Ember App to talk to your backend. But again, I think this is a subjective question/answer 'cause no one but you and your team can tell what's good for a given scenario you are or might be experiencing while the app gets created.
I think the guides explain the Adapter and Serializer role/usage and customization pretty decently these days.
As for implementing them, it may be necessary to create an adapter for your application to define a global namespace if you have one (if your controllers are behind another area like localhost:3000/api/products, then set namespace: 'api' otherwise this is not necessary), or similarly the host if you're using cors, and if you're doing with cli you might want to set the security policy in the environment to allow connections to other domains for cors and stuff like that. This can be done per model as well. But again, all of this is subjective as it depends on what you want/need to achieve.
I've been digging into the technical details and implementation of Windows Workflow 4.5 as a beginner and having decent results. My question is more of a "why and when" vs. a "how to" question so bear with me.
I've taken a familiar concept to us all and abstracted the business logic into WF, namely the universal log on process. What I wanted to accomplish is having reusable logic that I can call from an MVC website, a Windows Forms application, etc. and have everything run through the same workflow and I have achieved that.
Now I have 2 conceptual questions as to "when" to apply WF and when to use code.
1 - Take simple validation as an example. I'm trying to login but I've passed an empty user name or password string. Obviously, I want to send a message back to the end-user "UserName Required" and "Password Required", which I've done. Now, the way that I did that is I have a validation class (FluentValidation NuGet package if it matters) but the important thing is I'm doing this in code. So, in WF I call my validation code via an ExecuteMethod and everything works just fine. My question is: Is this the wrong approach with a WF mindset? Should I be doing inline WF "If" Actions/Decisions and building up the validation messages inside of WF directly versus calling out to some chunk of code? I'm asking not just for validation but as a concept we can all relate to but more generally should I be attempting to put anything and everything I can into WF itself or is it better to call custom code? I'm looking more for best practice with reasoning from seasoned Software Architects with WF experience versus someone's opinion if possible.
2 - Picking up a workflow on another machine. So, part of the same login workflow activity requires a service method call. I've written the code and workflow in such a way that the workflow receives an In parameter of ILogOnService which has an interface method "AuthenticateUser". The concrete implementation I'm passing in calls out to an MVC4 Web Api post method, in async, to do a standard Asp.Net membership ValidateUser. Again, should I be calling this Web Api PostAsync from inside the WF workflow? If so, doesn't that tightly-couple my workflow to Asp.Net Membership and my particular service choice. It seems there are ways to get the workflow to a certain point and then resume the process on another machine, e.g. where a service is running, and continue the process but I'm not able to find good examples of attempting that.
Just looking for some guidelines and ideas from the pros at this technology but I will pick the most informative answer.
There is nothing wrong with using C# code to implement details of a workflow. In fact I always tell people that if they are using WF4 with just the standard out of the box activities they are probably doing things wrong. You really need to be creating, or have someone else do it for your, custom activities that model business activities for your business. Now if that means creating an activity that validates a login using the FluentValidation that is perfectly fine. Another time you might build a higher level business activity out of lower level WF4 activities, just combine them as works best in your case.
Calling a service with something like PostAsync can work well if you know the action is short lived and is normally available. However when you get into SOA styles you really want to start using temporal decoupling so one service is not dependent on another service being available right away. And when you get into temporal decoupling you really want to be using queues, maybe MSMQ or maybe another similar technology. So in that cas you really want to send a one way message with a response queue and have to workflow go idle and wait for the response message to arrive. This would reload the workfloe, possibly on another machine. Now that might not always be appropriate, for example in your login it would not be much use to grant the login a day later because the membership service was unavailable, but can result in very scalable and fault tolerant systems. Of course there is no free lunch as these systems are very hard to design properly.
Clarified Updated Question - Start
In the official MVC 3 Getting Started-tutorial it seems to me that all we have to do to get ORM working are two steps.
First adding the simple MovieDBContext-code as described at the end of part 4 ..
public class MovieDBContext : DbContext
{
public DbSet<Movie> Movies { get; set; }
}
.. and second in the beginning of part 5, with a simple right-click on the Controllers folder we can auto-generate a MoviesController that implements CRUD()-functionality using Entity Framework by simply telling which Model to use.
Now when using the web-application we can already write and read from the database.
What would be the simplest (or a simple) way to get this done for our Movie-Model with NHibernate instead of using Entity Framework?
Clarified Updated Question - End
Original question (only for additional background-info):
I'm trying to create an ASP.Net MVC 3 application that uses NHibernate and Postgres.
Background Info
Development is done on Windows with Visual Web Developer Express, the production environment will be/should be Linux+Mono.
Steps that have worked so far:
An ASP.Net Dynamic Data Entities Web Application using Npgsql and Postgres as the DB.
Successfully run on Windows development machine.
(Following this tutorial)
An ASP.Net MVC 3 application without using a database/model yet:
Succesfully run on Windows development machine and deployed to Linux production environment using Mono and Nginx. (Only as a proof of concept for myself not as a web app used by the public.)
An ASP.Net MVC 3 application with a model using SQL Server Express as the DB.
Successfully run on my Windows development machine.
(Following the MVC 3 Getting Started-tutorial)
Question
So far I managed to get Postgres to work with a "Dynamic Data Entities Web Application" but with an MVC 3 Web app I'm stuck on where/how to start. For the last mentioned MVC-3-Movie-Webapp I want to switch the DB from SQL Server Express to Postgres using NHibernate and Npgsql (NHibernate since Mono doesn't support Entity Framework).
When you look at the end of part 4 there's the simple MovieDBContext-code
public class MovieDBContext : DbContext
{
public DbSet<Movie> Movies { get; set; }
}
and in the beginning of part 5, we autogenerate CRUD-stuff using Entity Framework by simply telling which Model to use.
(MoviesController.cs, Create.cshtml, Delete.cshtml, Details.cshtml, Edit.cshtml, and Index.cshtml)
So I have that working with Entity Framework and SQL Server Express, but how would I achieve the same result by using NHibernate? (doesn't have to be with postgres immediately, sticking with SQL-Server as a first step would be fine) (Hopefully with similar simplicity, but getting the result itself would be great)
I found a lot of old stuff and how I would manually map things, but what would be a good-up to date standard way of achieving this with NHibernate for MVC 3?
(The closest thing I found was the source code mentioned in this thread, but it's 64 MB unzipped I got several "Projects not loaded successfully"-errors and the author said he uses MVC 2 so I think it's a little over my head for being a complete NHibernate noob.)
I think showing how this is done could be very useful for others as well, since the original tutorial is very easy to follow and is linked as the official starting point for MVC 3 app-development on http://www.asp.net/mvc ("Your First ASP.NET MVC App").
So I think this would be a great up to date example about how to use NHibernate with MVC 3.
Actually, those automated things haven't helpful enough in real world applications. We have to separate concerns and by using DataContext in UI Layer is not a good practice because that dependency will cause problems like lack of test-ability, violation of best practices. I think you need to have following things of your project
Separation of Concern (Layered Architecture - UI Layer, Servie Layer, Domain Layer, Infrastructure Layer)
Generic Repository and Unit of Work wrapping (Database functionalities, ORM - EF, NHibernate, etc
In your Service Layer process repositories and unit of work processings and expose Data Transfer objects or your domain objects (POCOs) to UI Layer
Use IOC to inject dependencies will help you to minimize dependencies
Create Unit test and Integration tests
Use Continuous Integration and Source control prefer (Distributed: Mercurial)
Useful References:
(Sharp Architecture) http://sharparchitecture.codeplex.com/
(IOC Container) http://www.castleproject.org/container/
(Generic repository) http://code.google.com/p/genericrepository/
NuGet is your friend. Here's a good example of using NuGet to automatically wire in your dependencies and configuration pretty much automatically.
Hope this helps.
Suggestion, don't get hung up on all the automatic stuff that the tutorials are showing you. Microsoft is just trying to show that you can easily get things started if you don't try to do anything unique.
Now for your situation. When you're making a controller, you're wanting to bind that controller with a type of model that you created somewhere. With nHibernate I'm thinking that you'll have manually created these POCO's and that you're using one of the many ways to map those POCO's through nHibernate to your database.
You won't be able to use the Entity Framework options because they're depending upon the features of the framework to provide information on the object, database, etc. Easiest things is to just make a controller that either gives you the options for CRUD or use an empty controller to build up your own ActionResults.
Hope this helps some and good luck with your project.