[NEW][Apps] Add support to the "encoding" option in http requests from Apps

[shiqimei]

This PR allows apps to specify encoding option while performing an HTTP request.

In this way, apps can download binary data (Buffer) from an URL instead of utf8 string only.

Proposed changes

Forward encoding option into npmRequestOptions.

Issue(s)

https://open.rocket.chat/group/t9xgtnadgqwf3xkzh?msg=x5EsHiqtzv7rJj3qR (Private)

How to test or reproduce

import { IAppAccessors, IHttp, ILogger, IModify, IPersistence, IRead } from '@rocket.chat/apps-engine/definition/accessors';
import { App } from '@rocket.chat/apps-engine/definition/App';
import { ILivechatRoom } from '@rocket.chat/apps-engine/definition/livechat';
import { IMessage, IPostMessageSent } from '@rocket.chat/apps-engine/definition/messages';
import { IAppInfo } from '@rocket.chat/apps-engine/definition/metadata';
import { RoomType } from '@rocket.chat/apps-engine/definition/rooms';

export class FileUploadApp extends App implements IPostMessageSent {
    constructor(info: IAppInfo, logger: ILogger, accessors: IAppAccessors) {
        super(info, logger, accessors);
    }

    public async executePostMessageSent(message: IMessage, read: IRead, http: IHttp, persistence: IPersistence, modify: IModify): Promise<void> {
        try {
            if (!message.text || message.room.type !== RoomType.LIVE_CHAT) {
                return;
            }
            const agent = (message.room as ILivechatRoom).servedBy;
            const { content } = await http.get('https://ss1.bdstatic.com/70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=3640940258,545464235&fm=26&gp=0.jpg', {
                encoding: null,
            });

            for (const filename of Array(1).fill(Math.random())) {
                await modify.getCreator().getUploadCreator().uploadBuffer(content as any as Buffer, {
                    filename: `${ filename } sent by ${ agent && agent.name }.png`,
                    room: message.room,
                    user: agent,
                });
            }
        } catch (err) {
            console.error(err);
        }
    }
}

fileupload_0.0.1.zip

Screenshots

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves a current function)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Hotfix (a major bugfix that has to be merged asap)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works (if applicable)
• I have added necessary documentation (if applicable)
• Any dependent changes have been merged and published in downstream modules

Changelog

Further comments

[shiqimei]

Depends on: RocketChat/Rocket.Chat.Apps-engine#321