Strapi isOwner policy (non static)

isOwner.js

/*File /config/policies/isOwner.js */

module.exports = async (ctx, next) => {
  if (ctx.state.user) {
    const controller = ctx.request.route.controller;
    const o = `${strapi.config.ownmap[controller]}.id`;
    var data = {
      id: ctx.params.id
    };
    data[o] = ctx.state.user.id;
    const [owner] = await strapi.services[controller].find(data);
    if (!owner) {
      return ctx.unauthorized(`You don't have access to this entry`);
    }
    return await next();
  }
};

ownmap.js

/* file /config/ownmap.js */
/* this file contain a json to map all controller with the corresponding field */
/* For example if we have a Restaurant entity and and the owner in that entity is user then we ll map as follows: */

{
    "ownmap": {
        "restaurant": "user",
        "job": "owner"
    }
}

routes.json

/* File /api/restaurant/config/routes.json */
.....


    {
      "method": "PUT",
      "path": "/restaurants/:id",
      "handler": "restaurant.update",
      "config": {
        "policies": [
          "global::isOwner" //USAGE
        ]
      }
    },
    {
      "method": "DELETE",
      "path": "/restaurants/:id",
      "handler": "restaurant.delete",
      "config": {
        "policies": [
          "global::isOwner" //USAGE
        ]
      }
    },

....