server/packages/media-manager/index.ts

import type { Config } from "config-manager";

export enum MediaBackendType {
    LOCAL = "local",
    S3 = "s3",
}

interface UploadedFileMetadata {
    uploadedFile: File;
    path?: string;
    hash: string;
}

export class MediaHasher {
    /**
     * Returns the SHA-256 hash of a file in hex format
     * @param media The file to hash
     * @returns The SHA-256 hash of the file in hex format
     */
    public async getMediaHash(media: File) {
        const hash = new Bun.SHA256()
            .update(await media.arrayBuffer())
            .digest("hex");

        return hash;
    }
}

export class MediaBackend {
    constructor(
        public config: Config,
        public backend: MediaBackendType,
    ) {}

    static async fromBackendType(
        backend: MediaBackendType,
        config: Config,
    ): Promise<MediaBackend> {
        switch (backend) {
            case MediaBackendType.LOCAL:
                return new (await import("./backends/local")).LocalMediaBackend(
                    config,
                );
            case MediaBackendType.S3:
                return new (await import("./backends/s3")).S3MediaBackend(
                    config,
                );
            default:
                throw new Error(`Unknown backend type: ${backend as string}`);
        }
    }

    public getBackendType() {
        return this.backend;
    }

    public shouldConvertImages(config: Config) {
        return config.media.conversion.convert_images;
    }

    /**
     * Fetches file from backend from SHA-256 hash
     * @param file SHA-256 hash of wanted file
     * @param databaseHashFetcher Function that takes in a sha256 hash as input and outputs the filename of that file in the database
     * @returns The file as a File object
     */
    public getFileByHash(
        // eslint-disable-next-line @typescript-eslint/no-unused-vars
        file: string,
        // eslint-disable-next-line @typescript-eslint/no-unused-vars
        databaseHashFetcher: (sha256: string) => Promise<string>,
    ): Promise<File | null> {
        return Promise.reject(
            new Error("Do not call MediaBackend directly: use a subclass"),
        );
    }

    /**
     * Fetches file from backend from filename
     * @param filename File name
     * @returns The file as a File object
     */
    // eslint-disable-next-line @typescript-eslint/no-unused-vars
    public getFile(filename: string): Promise<File | null> {
        return Promise.reject(
            new Error("Do not call MediaBackend directly: use a subclass"),
        );
    }

    /**
     * Adds file to backend
     * @param file File to add
     * @returns Metadata about the uploaded file
     */
    // eslint-disable-next-line @typescript-eslint/no-unused-vars
    public addFile(file: File): Promise<UploadedFileMetadata> {
        return Promise.reject(
            new Error("Do not call MediaBackend directly: use a subclass"),
        );
    }
}