salix/back/methods/image/download.js

const UserError = require('vn-loopback/util/user-error');
const fs = require('fs-extra');

module.exports = Self => {
    Self.remoteMethod('download', {
        description: 'Get the user image',
        accessType: 'READ',
        accepts: [
            {
                arg: 'collection',
                type: 'String',
                description: 'The image collection',
                http: {source: 'path'}
            },
            {
                arg: 'size',
                type: 'String',
                description: 'The image size',
                http: {source: 'path'}
            },
            {
                arg: 'id',
                type: 'Number',
                description: 'The user id',
                http: {source: 'path'}
            }

        ],
        returns: [
            {
                arg: 'body',
                type: 'file',
                root: true
            },
            {
                arg: 'Content-Type',
                type: 'String',
                http: {target: 'header'}
            },
            {
                arg: 'Content-Disposition',
                type: 'String',
                http: {target: 'header'}
            }
        ],
        http: {
            path: `/:collection/:size/:id/download`,
            verb: 'GET'
        }
    });

    Self.download = async function(collection, size, id) {
        const filter = {
            where: {
                collectionFk: collection,
                name: id},
            include: {
                relation: 'collection',
                scope: {
                    fields: ['name', 'readRoleFk'],
                    include: {
                        relation: 'readRole'
                    }
                }
            }
        };
        const image = await Self.app.models.Image.findOne(filter);
        if (!image) return false;

        const imageRole = image.collection().readRole().name;
        const hasRole = await Self.app.models.Account.hasRole(id, imageRole);
        if (!hasRole)
            throw new UserError(`You don't have enough privileges`);

        let file;
        let env = process.env.NODE_ENV;
        if (env && env != 'development') {
            file = {
                path: `/var/lib/salix/image/${collection}/${size}/${id}.png`,
                contentType: 'image/png',
                name: `${id}.png`
            };
        } else {
            file = {
                path: `${process.cwd()}/storage/image/${collection}/${size}/${id}.png`,
                contentType: 'image/png',
                name: `${id}.png`
            };
        }
        await fs.access(file.path);
        let stream = fs.createReadStream(file.path);
        return [stream, file.contentType, `filename="${file.name}"`];
    };
};