salix/modules/entry/back/methods/entry-dms/removeFile.js

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

module.exports = Self => {
    Self.remoteMethodCtx('removeFile', {
        description: 'Removes a entry document',
        accessType: 'WRITE',
        accepts: {
            arg: 'id',
            type: 'number',
            description: 'The document id',
            http: {source: 'path'}
        },
        returns: {
            type: 'object',
            root: true
        },
        http: {
            path: `/:id/removeFile`,
            verb: 'POST'
        }
    });

    Self.removeFile = async(ctx, id, options) => {
        const myOptions = {};
        let tx;

        if (typeof options == 'object')
            Object.assign(myOptions, options);

        if (!myOptions.transaction) {
            tx = await Self.beginTransaction({});
            myOptions.transaction = tx;
        }

        try {
            const targetEntryDms = await Self.findById(id, null, myOptions);
            const targetDms = await Self.app.models.Dms.removeFile(ctx, targetEntryDms.dmsFk, myOptions);

            if (!targetDms)
                throw new UserError('Try again');

            const entryDmsDestroyed = await targetEntryDms.destroy(myOptions);

            if (tx) await tx.commit();

            return entryDmsDestroyed;
        } catch (e) {
            if (tx) await tx.rollback();
            throw e;
        }
    };
};