[V5] Creating a Service Provider

[remidosol]

Hello there, I'm wondering that how can I create service provider.

There is no page that tell me about providers in V5 docs and I'm trying to create a provider that will be use for CDN(AWS S3) transactions.

I've created a provider but I don't know how can I bind my service with its Config file to IoC container. I've created a config file that named as "services.ts" in config folder but when I look at to other config files (e.g. database.ts etc.), there is a type for this typed config file in ioc:Adonis/../.. (e.g. DatabaseConfig type etc.).

If I define these types in config file that I've created, does it will be effective? Otherwise where should I define these types for using this config file (services.ts) in the provider that I've create?

Actually this not the main problem, this was just an example. Is there a template for my problem? Thanks already.

[Banashek]

I don't think Service Provider docs exist for v5 yet.

My process for figuring out how they worked included:

1. Look at the v4 documentation
2. Look at the fold source to get an idea of how things wire up, specifically how it really just boils down to calling register for each provider, then calling boot for each provider
3. Looking at how some of the official providers work

Confusingly enough, the v4 service provider documentation states "The register method is used to register bindings, and you should never try to use any other binding inside this method", which is slightly confusing since some of the official providers explicitly call use with other service providers, however this rule might not apply when referencing core adonisjs providers. I have to look into this more to see if those are loaded before everything else.

Since it seems like the algorithm the application container follows is "call register on everything" -> "call boot on everything", I'm guessing that the general rule is:

1. Call as much as you can in register, but don't rely on any of the behavior of another provider's boot method (or any other services outside of core or registered later than this service).
2. Call anything that relies on other services' register results in boot.

To answer your concrete question, I'd look to the Official Redis Provider to see how it uses the Config to configure it's service.

[steschwa]

I've recently faced a similar problem (creating a service provider for S3 file management).

1. Run node ace make:provider ImageServiceProvider to create and register your Service Provider
2. Create the service (i've created a seperate folder /services inside the project root). Let's call it S3Service for now with the following stub:

import { MultipartFileContract } from "@ioc:Adonis/Core/BodyParser"

export class S3Service {
    public async upload(file: MultipartFileContract): Promise<void> {
        // Upload the file to your S3 provider ...
    }

    public async download(file: string): Promise<Readable> {
        // Stream file from S3 ...
    }
}

3. Register the S3Service class to get resolved by your Service Provider:

providers/ImageServiceProvider.ts

export default class ImageServiceProvider {
    public register() {
        this.container.singleton("MyCompany/ImageService", () => {
            const S3Service = require("../services/S3Service").S3Service // Maybe this can be improved (with import(...)?) 🤷‍♂️
            return new S3Service()
        })
    }
}

4. Inform Typescript about your custom IOC binding:

contracts/ImageService.d.ts

declare module "@ioc:MyCompany/ImageService" {
    import { S3Service } from "services/S3Service"
    const imageService: S3Service
    export default imageService
}

5. Import the IOC binding into your Controller etc.

app/Controllers/Http/ExampleController

import { HttpContextContract } from "@ioc:Adonis/Core/HttpContext"
import ImageService from "@ioc:MyCompany/ImageService"

export default class ExampleController {
    public async store({ request }: HttpContextContract) {
        // Validation ...
       
        if (validated.image?.tmpPath) {
            await ImageService.upload(validated.image) // 👈 with Typescript support
        }
    }
}

Because there isn't an official documentation yet, this solution may not be perfect.

You may also see here and here.

[remidosol]

I have to accept one mime type that is "multipart/form-data" from HTTP Request. So, I guess I'm gonna get the image fileS using request.files() method.

In your example's "app/Controllers/Http/ExampleController" part, there is a key that is named as tmpPath, what does this if's conditional statement control?

[steschwa]

If you don't want to validate your files (which i strongly discourage) you can use request.files() (Typed in adonisjs/bodyparser)

With validated.image?.tmpPath i check if the file is available on my local disk before uploading it to S3.

[remidosol]

If you don't want to validate your files (which i strongly discourage) you can use request.files() (Typed in adonisjs/bodyparser)

With validated.image?.tmpPath i check if the file is available on my local disk before uploading it to S3.

First: Maybe we can validate these files like below?
In a validation file:

    images: schema.array([
      rules.minLength(1),
      rules.maxLength(3)
    ]).members(
      schema.file({
        size: '1mb',
        extnames: ['.jpg']
      })
    )

And images's type looks like that:

Second: For uploading file/files to S3, is the file/files must be available on a local storage? Is is a necessity?

[steschwa]

1. Should work
2. The user sends the file to your API (and is temporary stored on your API server). I thought if the upload failed for some reason, your server cannot redirect (upload) it to the S3. That's why i've used if(validated.image?.tmpPath) { ... }