Instrument a graphql-java server with filters on lists
This is an extension to the excellent graphql-java that adds a parameter to each list field that allows to filter the elements of that list using a simple predicate.
Given this schema:
type Query {
result: [result]
}
type result {
int: Int
string: String
}
You could write the query:
{
result(_filter: {
int: {gt: 15),
string: {eq: "hello"}
}) {
int
string
}
}
This would retrieve the list of results as usual and then remove everything where int is not greater than 15 or string not equal to "hello".
GraphQL-Query is available from maven central: https://search.maven.org/artifact/net.bloemsma.graphql.query/graphql-query
See in the file "TestSchema.kt" how to add FilterInstrumentation to your GraphQL object:
val graphQL: GraphQL = GraphQL
.newGraphQL(oldSchema)
.instrumentation(FilterInstrumentation())
.build()- Fields used in the _filter argument have to be selected, either directly or using a fragment, using their original name. Otherwise the data to test on is simply not found.
- No calculations can be done, only comparisons of fields against literals.
- There are very few operators.
- No aggregations.
- No pagination.
- The code needs some serious cleanup!
- It should be easier to add new operators.
- Needs more tests.
- NOT ready for production.