example app for uploading files

uploadapp.ts

import {
    IAppAccessors,
    IConfigurationExtend,
    IEnvironmentRead,
    IHttp,
    ILogger,
    IModify,
    IPersistence,
    IRead,
} from '@rocket.chat/apps-engine/definition/accessors';
import { App } from '@rocket.chat/apps-engine/definition/App';
import { IAppInfo } from '@rocket.chat/apps-engine/definition/metadata';
import { ISlashCommand, SlashCommandContext } from '@rocket.chat/apps-engine/definition/slashcommands';
import { IUser } from '@rocket.chat/apps-engine/definition/users';

export default class UploadApp extends App {
    constructor(info: IAppInfo, logger: ILogger, accessors: IAppAccessors) {
        super(info, logger, accessors);
    }

    protected async extendConfiguration(configuration: IConfigurationExtend, environmentRead: IEnvironmentRead): Promise<void> {
        await configuration.slashCommands.provideSlashCommand(new (class implements ISlashCommand {
            command = "upload"
            i18nDescription: string = ""
            i18nParamsExample: string = ""
            providesPreview: boolean = false

            async executor(context: SlashCommandContext, read: IRead, modify: IModify, http: IHttp, persis: IPersistence): Promise<void> {
                const url = "https://www.africau.edu/images/default/sample.pdf"
                const res = await http.get(context.getArguments()[0] || url)
                if (!res.content) {
                    return;
                }
                modify.getCreator().getUploadCreator().uploadBuffer(Buffer.from(res.content, "utf-8"), {
                    filename: context.getArguments()[1] || 'dummy.pdf',
                    room: context.getRoom(),
                    user: (await read.getUserReader().getAppUser()) as IUser
                });
            }
        }))
    }
}