forked from Netflix/dgs-framework
/
DgsSSESubscriptionHandler.kt
157 lines (137 loc) · 6.67 KB
/
DgsSSESubscriptionHandler.kt
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/*
* Copyright 2021 Netflix, 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
*
* http://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.netflix.graphql.dgs.subscriptions.sse
import com.fasterxml.jackson.annotation.JsonProperty
import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
import com.netflix.graphql.dgs.DgsQueryExecutor
import com.netflix.graphql.types.subscription.DataPayload
import graphql.ExecutionResult
import graphql.InvalidSyntaxError
import graphql.validation.ValidationError
import org.reactivestreams.Publisher
import org.reactivestreams.Subscriber
import org.reactivestreams.Subscription
import org.slf4j.Logger
import org.slf4j.LoggerFactory
import org.springframework.http.MediaType
import org.springframework.http.ResponseEntity
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RequestParam
import org.springframework.web.bind.annotation.RestController
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter
import java.nio.charset.StandardCharsets
import java.util.*
/**
* This class is defined as "open" only for proxy/aop use cases. It is not considered part of the API, and backwards compatibility is not guaranteed.
* Do not manually extend this class.
*/
@RestController
open class DgsSSESubscriptionHandler(open val dgsQueryExecutor: DgsQueryExecutor) {
@RequestMapping("/subscriptions", produces = ["text/event-stream"])
fun subscriptionWithId(@RequestParam("query") queryBase64: String): ResponseEntity<SseEmitter> {
val emitter = SseEmitter(-1)
val sessionId = UUID.randomUUID().toString()
val query = try {
String(Base64.getDecoder().decode(queryBase64), StandardCharsets.UTF_8)
} catch (ex: IllegalArgumentException) {
emitter.send("Error decoding base64 encoded query")
emitter.complete()
return ResponseEntity.badRequest().body(emitter)
}
val queryPayload = try {
mapper.readValue(query, QueryPayload::class.java)
} catch (ex: Exception) {
emitter.send("Error parsing query: ${ex.message}")
emitter.complete()
return ResponseEntity.badRequest().body(emitter)
}
val executionResult: ExecutionResult = dgsQueryExecutor.execute(queryPayload.query, queryPayload.variables)
if (executionResult.errors.isNotEmpty()) {
return if (executionResult.errors.asSequence().filterIsInstance<ValidationError>().any() || executionResult.errors.asSequence().filterIsInstance<InvalidSyntaxError>().any()) {
val errorMessage = "Subscription query failed to validate: ${executionResult.errors.joinToString(", ")}"
emitter.send(errorMessage)
emitter.complete()
ResponseEntity.badRequest().body(emitter)
} else {
val errorMessage = "Error executing subscription query: ${executionResult.errors.joinToString(", ")}"
logger.error(errorMessage)
emitter.send(errorMessage)
emitter.complete()
ResponseEntity.status(500).body(emitter)
}
}
val subscriber = object : Subscriber<ExecutionResult> {
lateinit var subscription: Subscription
override fun onSubscribe(s: Subscription) {
logger.info("Started subscription with id {} for request {}", sessionId, queryPayload)
subscription = s
s.request(1)
}
override fun onNext(t: ExecutionResult) {
val event = SseEmitter.event()
.data(mapper.writeValueAsString(DataPayload(t.getData(), t.errors)), MediaType.APPLICATION_JSON)
.id(UUID.randomUUID().toString())
emitter.send(event)
subscription.request(1)
}
override fun onError(t: Throwable) {
logger.error("Error on subscription {}", sessionId, t)
val event = SseEmitter.event()
.data(mapper.writeValueAsString(DataPayload(null, listOf(Error(t.message)))), MediaType.APPLICATION_JSON)
emitter.send(event)
emitter.completeWithError(t)
}
override fun onComplete() {
emitter.complete()
}
}
emitter.onError {
logger.warn("Subscription {} had a connection error", sessionId)
subscriber.subscription.cancel()
}
emitter.onTimeout {
logger.warn("Subscription {} timed out", sessionId)
subscriber.subscription.cancel()
}
val publisher = try {
executionResult.getData<Publisher<ExecutionResult>>()
} catch (ex: ClassCastException) {
return if (query.contains("subscription")) {
logger.error("Invalid return type for subscription datafetcher. A subscription datafetcher must return a Publisher<ExecutionResult>. The query was $query", ex)
emitter.send("Invalid return type for subscription datafetcher. Was a non-subscription query send to the subscription endpoint?")
emitter.complete()
ResponseEntity.status(500).body(emitter)
} else {
logger.warn("Invalid return type for subscription datafetcher. The query sent doesn't appear to be a subscription query: $query", ex)
emitter.send("Invalid return type for subscription datafetcher. Was a non-subscription query send to the subscription endpoint?")
emitter.complete()
ResponseEntity.badRequest().body(emitter)
}
}
publisher.subscribe(subscriber)
return ResponseEntity.ok(emitter)
}
data class QueryPayload(
@JsonProperty("variables") val variables: Map<String, Any> = emptyMap(),
@JsonProperty("extensions") val extensions: Map<String, Any> = emptyMap(),
@JsonProperty("operationName") val operationName: String?,
@JsonProperty("query") val query: String
)
companion object {
private val mapper = jacksonObjectMapper()
private val logger: Logger = LoggerFactory.getLogger(DgsSSESubscriptionHandler::class.java)
}
}