Скачать или смотреть Implementing NestJS Middleware with Dependencies

Learn how to create powerful `NestJS` middleware with dependencies like Firebase and TypeORM using this step-by-step guide. Enhance your app's functionality effortlessly!
---
This video is based on the question https://stackoverflow.com/q/68396868/ asked by the user 'Tomer' ( https://stackoverflow.com/u/9509394/ ) and on the answer https://stackoverflow.com/a/68397158/ provided by the user 'Jay McDoniel' ( https://stackoverflow.com/u/9576186/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Nestjs middleware with dependencies

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Implementing NestJS Middleware with Dependencies - A Comprehensive Guide

NestJS is a powerful framework that allows you to build scalable server-side applications using Node.js. One of the essential features it offers is middleware, which helps you manage requests before they reach your route handlers. However, when dealing with middleware that has dependencies from other modules, things can get tricky. In this guide, we'll tackle a common problem faced when creating NestJS middleware with dependencies and provide a solution that you can apply to simplify your code structure.

The Problem: Middleware with Dependencies

Imagine you're working on a NestJS application where you want to implement middleware that relies on both TypeORM (to access your database) and Firebase (to handle authentication). You may find yourself struggling with dependency injection and module configurations. Here’s a look at what that setup typically looks like:

You have an AuthModule that imports FirebaseModule and TypeOrmModule.forFeature([User]), which manages user entities.

Your middleware (e.g., AuthMiddleware) requires both a repository of users and a service from Firebase.

You may be encountering errors regarding unavailable repositories or wondering how to set this up correctly in your app structure. The primary concerns often boil down to dependency injection and module scoping.

The Solution: Restructure Your Middleware Setup

Step 1: Adjust Your AuthModule Configuration

You won't need to re-add your AuthMiddleware to the AppModule's providers, as it already exists within the AuthModule. Here’s how you can streamline your module setup:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Middleware Registration

You can bind the middleware directly within the AuthModule instead of trying to set it up in the AppModule. This approach allows the middleware to have global scope while keeping your application organized.

Here's how you can configure it inside the AuthModule:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Simplifying the AppModule

Now, your AppModule does not need to worry about the middleware since it’s managed in the AuthModule. Here’s how your AppModule should look:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion: Middleware Management in NestJS

Creating middleware in NestJS with dependencies doesn’t have to be a headache. By properly structuring your modules and recognizing that you don’t need to duplicate the middleware in your AppModule, you can create a clean and efficient codebase. Here are some key takeaways:

Centralize Middleware: Keep all middleware registration within the respective module to maintain clarity and manageability.

No Redundant Providers: Avoid adding the same provider in multiple modules. Instead, focus on leveraging the module within which the dependencies reside.

Global Middleware: Employ middleware globally by configuring it within its module, which simplifies route handling.

By following these steps, your application will be easier to understand and maintain while keeping functionality robust and seamless.

If you have further questions or need more help with your NestJS application, feel free to ask!