GraphQL
Talk overview
- Quick introduction
- The type system
- Querying / mutating data
- Introspection
- Retrospection
Origin
- Developed at Facebook in 2012
- REST / custom endpoints / FQL
- Serves almost all of their mobile apps
{
hero {
name
}
}{
"hero": {
"name": "R2-D2"
}
}How does a query look like?
Formal specification
- Announcement at ReactConf in January
- Formal spec released at ReactConf in July
- https://facebook.github.io/graphql/
- Language and storage engine agnostic
The type system
- Strongly typed
- Types compose to a schema
- Schema sets entry points for queries & mutations
Formal definition (shorthand)
type Character {
id: String
name: String
friends: [Character]
homePlanet: String
}JavaScript
var CharacterType = new GraphQLObjectType({
name: 'Human',
fields: () => ({
id: {
type: new GraphQLNonNull(GraphQLString)
},
name: {
type: GraphQLString
},
friends: {
type: new GraphQLList(CharacterType),
resolve: (human) => human.friends.map(getFriend)
},
homePlanet: {
type: GraphQLString
},
})
});Querying data
{
hero {
name
friends {
name
}
}
}{
"hero": {
"name": "R2-D2",
"friends": [
{ "name": "Luke Skywalker" },
{ "name": "Han Solo" },
{ "name": "Leia Organa" }
]
}
}{
hero {
name
friends {
name
friends {
name
}
}
}
}{
"hero": {
"name": "R2-D2",
"friends": [
{
"name": "Luke Skywalker",
"friends": [
{ "name": "Han Solo" },
{ "name": "Leia Organa" },
{ "name": "C-3PO" },
{ "name": "R2-D2" }
]
},
{
"name": "Han Solo",
"friends": [
{ "name": "Luke Skywalker" },
{ "name": "Leia Organa" },
{ "name": "R2-D2" }
]
},
{
"name": "Leia Organa",
"friends": [
{ "name": "Luke Skywalker" },
{ "name": "Han Solo" },
{ "name": "C-3PO" },
{ "name": "R2-D2" }
]
}
]
}
}Mutating data
mutation M {
updateUser(userId: "1" name: "Bjoern Brauer") {
userId,
name
}
}Introspection
- Inspect the whole schema
- Validation of queries
- Platform for powerful tools
Retrospection
- No more over-/under-fetching of data
- Describe data dependencies naturally
- Works well with component hierachies (React.js)
Links
- http://graphql.org/ (docs, spec, official libraries)
- awesome-graphql (community maintained list)
- https://github.com/ZauberNerd/graphql-introduction
- writing-a-basic-api-with-graphql
Questions?
GraphQL
By Björn Brauer
GraphQL
Introduction to GraphQL.
- 478
