Questions tagged [dependency-injection]
Dependency Injection, is a design pattern where dependencies (instances of objects, properties) of a component are set through the constructor(s), methods or fields (properties). It is a special form of the more general dependency inversion.
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Can DI without the dependency inversion be replaced by protected properties?
Many people come from frameworks that implement Dependency Injection and IoC containers for everything (in my case Angular 2+), so, this group of people will try to use dependency injection and IoC ...
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Dependency injection into method calls
Let's use PHP here for examples and illustraion purposes but the question is language and framework agnostic.
Many experts say Service Locator (anti)pattern should be avoided and recommend using ...
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What is considered best practice for managing dependency injection for multiple libraries with ASP.NET Core Web API?
Suppose we are building a REST API with ASP.NET Core. Suppose there are 3 projects in our solution:
The ASP.NET Core Web API project.
A class library project for the businnes layer.
A class library ...
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better structure of a software project to prevent circular dependencies
I am contacting you today regarding a recent problem with circular dependencies. It's about a Spring boot application that accepts data via a Rest API and then forwards it to an internal Spring ...
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How to reconcile the fact that dependency Injection break encapsulation? (Especially when others are allowed to wire up your dependencies for you)
I was reading Martin Fowlers take on Dependency Injection, and in general have been trying to discuss it a bit online to help get rid of my own misconceptions and to understand this principle better.
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Please explain the "swapable dependency" arguments for IOC containers
I get that IOC containers can be useful to help break dependencies and allow you to test a class in isolation. I don't wish to focus on that right now, instead, I'm trying to understand some of the ...
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Passing data into Repository via dependency injection
Let's say I have a blog, I use DDD approach, I need to pass an instance of PaginationParameters class to PostsRepository, is it ok to bind DI container to concrete instance of PaginationParameters ...
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Relevance of dependency Injection
During my career I only used DI to insert object of certain class based on certain interface. So there was never the situation when I needed two different bindings for one interface.
So natural ...
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Why is Dependency Injection called "alternative of global state"?I think global state still exists
According to Why is Global State so Evil?, I believe we should avoid global state, so suppose I have an App that count user clicks in all pages like it:
public class GlobalState{
public int ...
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If you use Inversion of Control, what alternatives to obfuscated function calls exist?
Consider a class that follows the obfuscated function call anti-pattern. I've also seen these called "stupid classes". The definition of such a class is that it only has one public method ...
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Dependency Injection Usage
I'm very new to DI, and must admit, am having a hard time understanding to what extent it should be used in an application.
Even in a basic project, you can have hundreds of classes that have ...
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Is having many build-once factories a sign of bad dependency injection design?
I have a form. It contains things like grids. Users do things with these grids and what they do with them is sent to a SQL server. Clearly, the server is a volatile dependency and should be dependency ...
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Is it okay to use Dependency injection only because of unit testing?
I have a class that has dependencies that I know are not going to change.
class ConversationFinder
{
public function __construct(
protected Conversation $conversationDbFinder = new ...
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In .net 6 dependency injection and Program.cs, what is the best practice for handling a large number of dependencies?
I've seen a ton of examples of how to do DI, and the example always shows two dependencies. But what about when you have 50 or 100 dependencies (or more) in a large-ish application? The Program.cs ...
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Is it best practice for each call to a SQL Server to be in its own class, even when using dependency injection?
I often see/write classes that contain every part of the application where the application will talk to a SQL server. For example, you may have a class like this
public class Data
{
private Func&...
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How to handle dependency injection in a library to avoid frequent breaking changes?
Let's say I have a C# .NET library with the following classes:
public class FooService
{
private readonly IDependencyA a;
public FooService(IDependencyA a)
{
this.a = a;
}
...
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Dependency injection using method injection vs constructor injection
Where should I inject the dependency when I write a class? Should it be given to __init__ or to the specific method that uses the dependent object?
Take the below two pieces of code for example, to me ...
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Composite repositories: minimizing dependency injections
I have an application with dependency injection that consumes a REST API. The API calls are abstracted into entity-specific repositories. Some of the repositories are: HttpNotebookRepository, ...
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WPF plugin system - Dependency injection in plugin class libraries
The main application loads plugins, list them and when user selects one it is initialized and displayed. Each plugin is a complex class library which contains several views/viewmodels/repositories/etc....
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Dependency injection in legacy code
I have a legacy project with many classes with high coupling, and I have a necessity to test some of them. So, I decided to introduce dependency injection principle but stumbled upon where to create ...
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Injecting Adapters Into Client
So I'm building a client for a third API and I want to be able to Get() and GetMany() for each type this controller can provide.
So I've built this adapter, that provides generically typed methods for ...
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Benefit of using Dependency Injection inside ASP.NET Core MVC
I am reading this article about using DI inside ASP.NET Core @ https://learn.microsoft.com/en-us/aspnet/core/fundamentals/dependency-injection?view=aspnetcore-6.0 .. but i can not understand its ...
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Dependency Injection with multiple, dynamically created objects
All guides and blog posts that I have read about dependency injection use a simple example where one object A depends on one object B. They apply DI by creating object B somewhere else and passing it ...
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Why do we separate interface when implementing interface injection variant of DI?
With interface injection (wikpedia) we have a method to set the dependency on the client as part of an interfase.
public interface ServiceSetter {
public void setService(Service service);
}
Why ...
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Best practices when it comes to extending Service collections in .NET for dependency injection
Most of the information that I can find online is about how to do basic dependency injection in the common flows. eg one DI container where services are registered.
For a project we are writing a ...
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Dependency Injection vs Static Dependencies
I am building a wrapper for a library that requires little complex logic. The whole project is 8 builder classes, 4 classes for doing some pre-processing, and a couple visitor classes. Essentially I ...
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Abstracting calls to common library methods in C#
I‘m working on making a legacy code base more testable and made good progress with (constructor)-injecting dependencies to classes.
I noticed something in all classes that access the file system: they ...
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Inheritance/Composition VS "Direct Injection Construction"
my following example seems to go into the direction Inheritance VS Composition. But that's not, what i want to ask. I see the concept Inheritance and Composition on one side and the alternative, which ...
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Java Library - How to do Pure Dependency Injection When State is a Factor?
To set the stage, I am trying to do pure dependency injection for a Java Library I am creating to make it more testable. As it is a library, I want to do pure dependency injection without creating a ...
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Correct IHttpClientFactory implementation with dependency injection?
In Microsoft's documentation, in the Named Clients example, they retrieve an HttpClient from the IoC container:
var httpClient = _httpClientFactory.CreateClient("GitHub");
In the Typed ...
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Is It Considered Good Practice to Use Dependency Injection with Strategies from a NuGet Package?
I am developing a NuGet package which contains shared code for various ASP.NET Core projects. I am planning to use the strategy pattern to solve the same problem in a few different ways. So there will ...
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Android + Kotlin + Hilt + multi-module app: Should I "migrate" all classes with static methods to "injection"?
With the purpose of learning Hilt I started "migrating" my multi-module Kotlin app from using classes with static methods as helpers to Hilt injection.
After a lot of headaches, now ...
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DI: Injecting interfaces vs actual classes
In my job I work with C# (although the language is irrelevant for my question, and now I'd like to focus on Android) and we usually inject interfaces and not the actual classes, so I was wondering ...
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Android + Kotlin + Hilt: Dependency Injection vs Static Methods
I've already read this carefully, but still need more clarification.
I'm not new to dependency injection, but new to Hilt, and trying to implement Hilt in my multi-module app.
The reason?
I currently ...
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C# - Class creating instances of other classes requiring different services
Context
I have a service class whose sole purpose is to interact with a specific API, let's say the Automotive API. The API mostly works with generic AutomativeRecord which basically represents a ...
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Dependency Injection for dynamic objects
I am learning about Dependency Injection and I have been recently implementing the following classes for an app that executes commands over ssh using Python. I am confused about whether I am using it ...
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Is going through network during DI anti pattern?
So I want to inject an Application Client, say a Rest Api client, in my code. In order to create this client I need to go over the network to get it's user and password that is in a HTTP Vault.
This ...
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Dependency injection vs function parameter
I am working on a project that is structured in hexagonal architecture. It is a multi module gradle project where web layer is a separate module that depends on the domain module.
Sample code related ...
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Is it a bad practice to manipulate the behaviour of a class by replacing it's DI arguments?
I am well aware of a programming-to-an-interface term. That's a good thing! I understand that these allow to add decorators; or perhaps one can implement a service that works faster and by injecting ...
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Externally relying on the method call of the DI class means introducing a dependency on the implementation detail?
So I've got a class that calculates a discount (Let's call it class "A"). It has a price fetcher class as a dependency (constructor injection) (Class "B"). The price that is ...
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Struggle with catch 22 in initialization code
I have a command line application written in C#. Here's some facts about the program that are relevant to my question:
The application has a "data directory" (e.g. ~/.config/myapp) where ...
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Would Injecting dependencies in C# as default parameters be a bad practice?
Given the (old) debate over whether Singletons are overused/abused/are worth it - would it be a bad idea to inject the dependencies as default parameters? In this way, we could get rid of defining ...
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How Should I Go About Refactoring My Code With Dependency Injection? [closed]
I work on WPF applications used in testing hardware. I need to make my code base more testable and re-usable. I believe DI would help, but I'm not quite sure where to start. I've done my best with the ...
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WPF Best way to create viewmodel from another viewmodel
Often I want to open a new window from within some view.
I see opening a window as view logic. So I don't want code in my viewmodel that creates/opens/changes windows or anything else that interacts ...
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Best way make a complex libraries as a plugin with dependency inversion principle [closed]
For instance, if we have a complex library with many functionalities, how can we make this lib a plugin such that it can be replaced with another lib more easily.
The answer obviously is the ...
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How to get an ILogger instance from extension methods?
Let's say I have this service abstraction exposed from a library.
public interface INavigator
{
ImmutableList<IPageViewModel> Entries { get; }
void NavigateForward(IPageViewModel page);
...
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Golang interface-implementation circular dependency
In trying to separate interface from implementation, I ran into a circular dependency problem.
There is a best practice in the world of Java: consume interfaces instead of concrete classes. That is, ...
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Services should depend on Data or Factories?
I have app which uses IOC container. I have services registered in container, and I can consume either data factory, or particular data object. Which approach is preffereable?
Consuming factory object:...
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Instability metric vs Dependency Injection
Below is an excerpt of Fundamentals of Software Architecture, page 65, which I am reading:
The instability metric determines the volatility of a code base. A
code base that exhibits high degrees of ...
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Plugin system design core component access: Common practice?
I wonder how to design a good plugin architecture in C++/Qt. The main concern I have is about dependency injection vs globals when it comes to the core components. Plugins should have access to ...
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