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Dynamic route resolver

DynamicRouteResolver handles dynamic route resolution for the client application. When a user goes to a page that is not defined in React routing - then the client will ask the back-end for the type of content for that particular url:

  • It asks every extension to get "fetch URL priority" from the assigned API DataSource instance
  • It sorts API DataSource instances that are able to determine dynamic content type by their "priority"
  • It calls fetchUrl method on every available API DataSource until it gets a proper response

Example​

The simplest example is handling content from shop and blog. Let's say we want to resolve content for /sport.html

class Magento2Api {
    getFetchUrlPriority(url) {
        // if url ends with .html then it's highly possible that it should be handed by shop
        // because it might be a product page under url generated by Magento
        return url.endsWith('.html') ? ApiUrlPriority.HIGH : ApiUrlPriority.NORMAL;
    }

    fetchUrl(obj, args, context, info) {
        // implementation of the resolver
    }
}
class WordpressApi {
    getFetchUrlPriority(url) {
        // return just static value so others can be higher or lower
        return ApiUrlPriority.NORMAL;
    }

    fetchUrl(obj, args, context, info) {
        // implementation of the resolver
    }
}

DynamicRouteResolver will try to call getFetchUrlPriority(url) method for both extensions:

  • ShopExtension/Magento2Api will return ApiUrlPriority.HIGH
  • BlogExtension/WordpressApi will return ApiUrlPriority.NORMAL

So in that case DynamicRouteResolver will call ShopExtension.fetchUrl() first, if that call returns null, it will call BlogExtension.fetchUrl() second.

By default the API priority order is the order they are added in your server/config/default.json file. With the first API being checked first. If the priorities are the same this order will be used.

We provide these orders:

@deity/falcon-server-env/src/types.ts

export enum ApiUrlPriority {
  HIGHEST = 1,
  HIGH = 2,
  NORMAL = 3,
  LOW = 4,
  LOWEST = 5,
  OFF = 0
}

DynamicRouteResolver result structure​

The correct response must match the following structure:

{
    "id": 1,
    "path": "/foo.html",
    "type": "foo-type",
    "redirect": false
}
  • id - must represent a unique ID for your back-end
  • path - must represent a canonical path for your entity (this will be used for a possible redirection situation)
  • type - must represent a unique entity type that will be later used by DynamicRoute component on falcon-client
  • redirect - must set a flag whether the given URL must be redirected to the path address (to ensure canonical URL)

Requirements​

If any extension should handle dynamic routing it should implement both methods:

  • getFetchUrlPriority(url) - accepts url (string) that should be resolved and returns the priority (number) for the extension
  • fetchUrl(obj, args, context, info) - fetches the data from the remote source or performs any other async logic to determine the type of the given url and returns a correct result or null (if the given URL is not determined by your back-end)