/
ExampleSubscriptionService.kt
77 lines (67 loc) · 2.66 KB
/
ExampleSubscriptionService.kt
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/*
* Copyright 2023 Expedia, Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.expediagroup.graphql.examples.server.ktor.schema
import com.expediagroup.graphql.generator.annotations.GraphQLDescription
import com.expediagroup.graphql.server.operations.Subscription
import graphql.GraphqlErrorException
import graphql.execution.DataFetcherResult
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.flow
import kotlinx.coroutines.flow.flowOf
import kotlinx.coroutines.flow.map
import kotlinx.coroutines.reactive.asPublisher
import org.reactivestreams.Publisher
import kotlin.random.Random
class ExampleSubscriptionService : Subscription {
@GraphQLDescription("Returns a single value")
fun singleValue(): Flow<Int> = flowOf(1)
@GraphQLDescription("Returns stream of values")
fun multipleValues(): Flow<Int> = flowOf(1, 2, 3)
@GraphQLDescription("Returns a random number every second")
suspend fun counter(limit: Int? = null): Flow<Int> = flow {
var count = 0
while (true) {
count++
if (limit != null) {
if (count > limit) break
}
emit(Random.nextInt())
delay(1000)
}
}
@GraphQLDescription("Returns a random number every second, errors if even")
fun counterWithError(): Flow<Int> = flow {
while (true) {
val value = Random.nextInt()
if (value % 2 == 0) {
throw Exception("Value is even $value")
} else emit(value)
delay(1000)
}
}
@GraphQLDescription("Returns one value then an error")
fun singleValueThenError(): Flow<Int> = flowOf(1, 2)
.map { if (it == 2) throw Exception("Second value") else it }
@GraphQLDescription("Returns stream of errors")
fun flowOfErrors(): Publisher<DataFetcherResult<String?>> {
val dfr: DataFetcherResult<String?> = DataFetcherResult.newResult<String?>()
.data(null)
.error(GraphqlErrorException.newErrorException().cause(Exception("error thrown")).build())
.build()
return flowOf(dfr, dfr).asPublisher()
}
}