pluto/docs/concepts/Query.md

title, sidebar_label

title	sidebar_label
Query	Query

Query

Queries are exposed by the platform in the form of :queries key in the capacities map. Only those queries which are exposed can be either referenced by hook property (when the property is of the type :query), or used to read data in let block in view (eq (let [network-name (query [:get-in [:network :name]])] [text {} network-name])).

Query as hook property

To refer to some query via hook property (might be required for some host app hooks), the property must be defined as :query type by the app-hook and extension must correctly refer to query from capacities map.

Example

;; App hook code in host application
(reify host/AppHook
  (id [_] :wallet-asset)
  (properties [_] {:able-to-send :query}))
  
;; Capacities map in the host application
{:capacities {:queries #{:network-up}}}

;; Extension hook data
hooks/wallet-asset.next-coin
{:able-to-send :network-up}

Queries in views

To use some queries in extension defined view, the query must be exposed via capacities map of the host platform.

Example

;; Capacities map in the host application
{:capacities {:queries #{:get-in}}}

;; Extension view data
views/coin-item
[view {}
  (let [current-network (query [:get-in [:networks :current :name]])]
    [text {} "Current network: "]
      [text {} current-network]])

Queries permission checking

There is a special treatment for generic query :get-in where it's data path (where to read data from app-state exposed by host platform) is checked against the declared [:permissions :read] map in the capacities. Whenever this check fails (extension is reading data in view not exposed the host), meaningfull parse error will be produced.