====== 3.1 Osnove GraphQL-a ======

GraphQL((GraphQL specifikacija: https://spec.graphql.org/)) omogućuje fleksibilne, precizne upite podataka.

===== Što je GraphQL? =====

GraphQL((GraphQL Foundation: https://graphql.org/)) je jezik upita za API-je i runtime okruženje za izvršavanje tih upita. Za razliku od REST-a((Representational State Transfer: https://de.wikipedia.org/wiki/Representational_State_Transfer)), klijenti mogu zatražiti točno one podatke koji su im potrebni.

===== Endpoint =====

<code>
POST /api/v1/dsn/{dbName}/graphql
Content-Type: application/json
</code>

===== Jednostavan upit =====

<code javascript>
{
  "query": "{ customers { id name country } }"
}
</code>

===== S parametrima =====

<code javascript>
{
  "query": "{ customers(first: 10, filter: \"Country eq 'DE'\") { id name } }"
}
</code>

===== Dohvaćanje sheme =====

<code>
GET /api/v1/dsn/demo/graphql/schema
</code>

Vraća GraphQL shemu u SDL((Schema Definition Language: https://graphql.org/learn/schema/)) formatu.

===== Prednosti u odnosu na REST =====

^ Aspekt ^ REST ^ GraphQL ^
| Endpointi | Mnogo (po resursu) | Jedan |
| Over-fetching | Često | Nikad |
| Under-fetching | Često (N+1) | Nikad |
| Tipska sigurnost | Opcionalno | Ugrađeno |
| Dokumentacija | Vanjska (OpenAPI((OpenAPI Specification: https://www.openapis.org/))) | Integrirana (Introspection) |

===== Izvori =====

  * [[https://graphql.org/|GraphQL Foundation - Službena stranica]]
  * [[https://spec.graphql.org/|GraphQL specifikacija]]
  * [[https://graphql.org/learn/|GraphQL Learn]]