planka/server/api/controllers/users/update-avatar.js

const Errors = {
  USER_NOT_FOUND: {
    userNotFound: 'User not found',
  },
};

module.exports = {
  inputs: {
    id: {
      type: 'string',
      regex: /^[0-9]+$/,
      required: true,
    },
  },

  exits: {
    userNotFound: {
      responseType: 'notFound',
    },
    uploadError: {
      responseType: 'unprocessableEntity',
    },
  },

  async fn(inputs, exits) {
    const { currentUser } = this.req;

    let user;
    if (currentUser.isAdmin) {
      user = await sails.helpers.getUser(inputs.id);

      if (!user) {
        throw Errors.USER_NOT_FOUND;
      }
    } else if (inputs.id !== currentUser.id) {
      throw Errors.USER_NOT_FOUND; // Forbidden
    } else {
      user = currentUser;
    }

    this.req.file('file').upload(sails.helpers.createAvatarReceiver(), async (error, files) => {
      if (error) {
        return exits.uploadError(error.message);
      }

      if (files.length === 0) {
        return exits.uploadError('No file was uploaded');
      }

      user = await sails.helpers.updateUser(
        user,
        {
          avatarDirname: files[0].extra.dirname,
        },
        this.req,
      );

      if (!user) {
        throw Errors.USER_NOT_FOUND;
      }

      return exits.success({
        item: user.toJSON().avatarUrl,
      });
    });
  },
};