veniaClojure(Script) graphql query generation
venia
A Clojure(Script) qraphql query client library. Generate valid graphql queries with Clojure data structures.
Usage
Venia is originally supposed to be used in Clojurescript apps, but can be used as well in Clojure, as the core is written in CLJC. The sole purpose of this library is graphql query string generation from Clojure data, so that strings concatenations and manipulations could be avoided when using grapqhl. It is up to developers to hook it up to frontend apps. However, at least some sort of re-frame-graphql-fx library is on a roadmap.
Simple query
The easiest way to start with venia, is simple's query generation.
(ns my.project
(:require [venia.core :as v]))
(v/graphql-query {:venia/queries [[:employee {:id 1 :active true} [:name :address [:friends [:name :email]]]]]})
=> "{employee(id:1,active:true){name,address,friends{name,email}}}" Obviously, If we would like to fetch employees and projects within the same simple query, we would do it this way:
(v/graphql-query {:venia/queries [[:employee {:id 1 :active true} [:name :address [:friends [:name :email]]]]
[:projects {:active true} [:customer :price]]]})
=> "{employee(active:true){name,address},project(active:true){customer,price}}" Field arguments
In the example above, :employee and :projects fields have arguments {:id 1 :active true} and {:id 1 :active true} respectively.
We can add arguments to other fields easily by wrapping field name and its arguments to vector [:customer {:id 2}]:
(v/graphql-query {:venia/queries [[:projects {:active true} [[:customer {:id 2}] :price]]]})
=> "{project(active:true){customer(id:2),price}}" Query with alias
Now, if we need to have an alias for query, it can be easily achieved by using venia's query-with-data map
(v/graphql-query {:venia/queries [{:query/data [:employee {:id 1 :active true} [:name :address [:friends [:name :email]]]]
:query/alias :workhorse}
{:query/data [:employee {:id 2 :active true} [:name :address [:friends [:name :email]]]]
:query/alias :boss}]})
=> prettified:
{
workhorse: employee(id: 1, active: true) {
name
address
},
boss: employee(id: 2, active: true) {
name
address
}
} In the query above, we use :query/data key for query definition and :query/alias for query's alias definition.
Query with fragments
What about fragments? Just add :venia/fragments vector with fragments definitions
(v/graphql-query {:venia/queries [{:query/data [:employee {:id 1 :active true} :fragment/comparisonFields]
:query/alias :workhorse}
{:query/data [:employee {:id 2 :active true} :fragment/comparisonFields]
:query/alias :boss}]
:venia/fragments [{:fragment/name "comparisonFields"
:fragment/type :Worker
:fragment/fields [:name :address]}]})
=> prettified:
{
workhorse: employee(id: 1, active: true) {
...comparisonFields
}
boss: employee(id: 2, active: true) {
...comparisonFields
}
}
fragment comparisonFields on Worker {
name
address
} Query with variables
Now you can generate really complex queries with variables as well. In order to define variables, we need to define an operation type and name.
(v/graphql-query {:venia/operation {:operation/type :query
:operation/name "employeeQuery"}
:venia/variables [{:variable/name "id"
:variable/type :Int
:variable/default 1}
{:variable/name "name"
:variable/type :String}]
:venia/queries [{:query/data [:employee {:id :$id
:active true
:name :$name}
:fragment/comparisonFields]
:query/alias :workhorse}
{:query/data [:employee {:id :$id
:active false}
:fragment/comparisonFields]
:query/alias :boss}]
:venia/fragments [{:fragment/name "comparisonFields"
:fragment/type :Worker
:fragment/fields [:name :address [:friends [:name :email]]]}]})
=> prettified:
query employeeQuery($id: Int = 1, $name: String) {
workhorse: employee(id: $id, active: true, name: $name) {
...comparisonFields
}
boss: employee(id: $id, active: false) {
...comparisonFields
}
}
fragment comparisonFields on Worker {
name
address
friends {
name
email
}
}
Mutation
Mutations are also supported, just use :mutation operation type:
(v/graphql-query {:venia/operation {:operation/type :mutation
:operation/name "AddProjectToEmployee"}
:venia/variables [{:variable/name "id"
:variable/type :Int!}
{:variable/name "project"
:variable/type :ProjectNameInput!}]
:venia/queries [[:addProject {:employeeId :$id
:project :$project}
[:allocation :name]]]})
=> prettified:
mutation AddProjectToEmployee($id:Int!,$project:ProjectNameInput!) {
addProject(employeeId:$id, project:$project) {
allocation,
name
}
} Validation
Venia will verify that you don't use undefined variables or fragments.
For example, the following v/graphql-query calls will throw exceptions:
(v/graphql-query {:venia/queries [[:employee {:id 1 :active true} :fragment/undefined]]}
(v/graphql-query {:venia/queries [[:employee {:id 1 :active :$undefined} [:name]]]})) because fragment and variable are never defined.
Meta fields
You can use graphql's __typename meta field anywhere inside of your query. For example:
(v/graphql-query {:venia/queries [[:employee [:meta/typename :name :address]]}
=> prettified:
{
employee {
__typename,
name,
address
}
}
License
Copyright © 2017 Vincit
Distributed under the Eclipse Public License, the same as Clojure.