commonMain.com.algolia.client.transport.internal.KtorRequester.kt Maven / Gradle / Ivy

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"Algolia is a powerful search-as-a-service solution, made easy to use with API clients, UI libraries, and pre-built integrations. Algolia API Client for Kotlin lets you easily use the Algolia Search REST API from your JVM project, such as Android or backend implementations."
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package com.algolia.client.transport.internal

import com.algolia.client.configuration.CallType
import com.algolia.client.configuration.Host
import com.algolia.client.configuration.internal.HEADER_APIKEY
import com.algolia.client.exception.AlgoliaRetryException
import com.algolia.client.exception.internal.asApiException
import com.algolia.client.exception.internal.asClientException
import com.algolia.client.transport.RequestConfig
import com.algolia.client.transport.RequestMethod
import com.algolia.client.transport.RequestOptions
import com.algolia.client.transport.Requester
import io.ktor.client.*
import io.ktor.client.call.*
import io.ktor.client.network.sockets.*
import io.ktor.client.plugins.*
import io.ktor.client.request.*
import io.ktor.client.utils.*
import io.ktor.http.*
import io.ktor.util.*
import io.ktor.util.reflect.*
import io.ktor.utils.io.errors.*
import kotlinx.coroutines.CancellationException
import kotlinx.coroutines.sync.Mutex
import kotlinx.coroutines.sync.withLock
import kotlinx.serialization.json.JsonObject
import kotlin.time.Duration

/** Default implementation of [Requester] using Ktor's [HttpClient]. */
public class KtorRequester(
  public val httpClient: HttpClient,
  private val connectTimeout: Duration,
  private val readTimeout: Duration,
  private val writeTimeout: Duration,
  hosts: List,
) : Requester {

  private val hostStatusExpirationDelayMS: Long = 1000L * 60L * 5L
  private val mutex: Mutex = Mutex()
  private val retryableHosts = hosts.map { RetryableHost(it) }

  public override fun setClientApiKey(apiKey: String) {
    headers {
      if (contains(HEADER_APIKEY)) {
        remove(HEADER_APIKEY)
      }
      append(HEADER_APIKEY, apiKey)
    }
  }

  override suspend fun  execute(
    requestConfig: RequestConfig,
    requestOptions: RequestOptions?,
    returnType: TypeInfo,
  ): T {
    val callType = callTypeOf(requestConfig)
    val hosts = callableHosts(callType)
    val errors by lazy(LazyThreadSafetyMode.NONE) { mutableListOf() }
    val requestBuilder = httpRequestBuilderOf(requestConfig, requestOptions)

    for (host in hosts) {
      requestBuilder.url.protocol = URLProtocol.createOrDefault(host.protocol)
      requestBuilder.url.host = host.url
      if (host.port != null) {
        requestBuilder.url.port = host.port!!
      }
      requestBuilder.setTimeout(requestOptions, callType, host)
      try {
        val response = httpClient.request(requestBuilder)
        val body = response.body(returnType)
        mutex.withLock { host.reset() }
        return body
      } catch (exception: Throwable) {
        host.onError(exception)
        errors += exception.asClientException()
      }
    }
    throw AlgoliaRetryException(errors)
  }

  private fun callTypeOf(requestConfig: RequestConfig): CallType {
    return if (requestConfig.isRead || requestConfig.method == RequestMethod.GET) {
      CallType.Read
    } else {
      CallType.Write
    }
  }

  /** Get list of [RetryableHost] for a given [CallType]. */
  private suspend fun callableHosts(callType: CallType): List {
    return mutex.withLock {
      retryableHosts.expireHostsOlderThan(hostStatusExpirationDelayMS)
      val hostsCallType = retryableHosts.filterCallType(callType)
      val hostsCallTypeAreUp = hostsCallType.filter { it.isUp }
      hostsCallTypeAreUp.ifEmpty { hostsCallType.onEach { it.reset() } }
    }
  }

  /** Handle API request exceptions. */
  private suspend fun RetryableHost.onError(throwable: Throwable) {
    when (throwable) {
      is CancellationException -> throw throwable // propagate coroutine cancellation
      is ClientRequestException -> throw throwable.asApiException()
      is HttpRequestTimeoutException,
      is SocketTimeoutException,
      is ConnectTimeoutException -> mutex.withLock { hasTimedOut() }
      is IOException,
      is ResponseException -> mutex.withLock { hasFailed() }
      else -> throw throwable.asClientException()
    }
  }

  /** Set socket read/write timeout. */
  private fun HttpRequestBuilder.setTimeout(
    requestOptions: RequestOptions?,
    callType: CallType,
    host: RetryableHost,
  ) {
    timeout {
      val timeout =
        when (callType) {
          CallType.Read -> requestOptions?.readTimeout ?: readTimeout
          CallType.Write -> requestOptions?.writeTimeout ?: writeTimeout
        }
      connectTimeoutMillis = connectTimeout.inWholeMilliseconds
      socketTimeoutMillis = timeout.inWholeMilliseconds * (host.retryCount + 1)
    }
  }

  private fun List.expireHostsOlderThan(hostStatusExpirationDelayMS: Long) {
    forEach {
      val timeDelayExpired = currentTimeMillis() - it.lastUpdated
      if (timeDelayExpired > hostStatusExpirationDelayMS) {
        it.reset()
      }
    }
  }

  private fun List.filterCallType(callType: CallType): List {
    return filter { it.callType == callType || it.callType == null }
  }

  private fun httpRequestBuilderOf(
    requestConfig: RequestConfig,
    requestOptions: RequestOptions? = null,
  ): HttpRequestBuilder {
    return HttpRequestBuilder().apply {
      url {
        pathSegments = requestConfig.path
      }
      method = requestConfig.method.ktorHttpMethod
      contentType(ContentType.Application.Json)

      requestConfig.run {
        requestHeaders(headers)
        queryParameter(query)
        when {
          body != null -> setBody(body.body, body.bodyType)
          requiresBody(requestConfig) -> setBody(EmptyObject)
          else -> setBody(EmptyContent)
        }
      }

      requestOptions?.run {
        requestHeaders(headers)
        queryParameter(urlParameters)
        body?.let { setBody(it) }
      }
    }
  }

  private fun requiresBody(requestConfig: RequestConfig) =
    requestConfig.method == RequestMethod.POST || requestConfig.method == RequestMethod.PUT

  private fun HttpRequestBuilder.requestHeaders(headerOptions: Map) {
    headers.replaceAll(headerOptions)
  }

  private fun HttpRequestBuilder.queryParameter(parameters: Map) {
    url.encodedParameters.replaceAllEncoded(parameters)
  }

  private fun StringValuesBuilder.replaceAllEncoded(input: Map) {
    input.onEach { (key, value) ->
      if (contains(key)) remove(key)
      when (value) {
        is Iterable<*> -> append(
          key.encodeURLParameter(),
          value.joinToString(",") {
            it.toString()
          }.encodeURLParameter(),
        )
        else -> append(key.encodeURLParameter(), value.toString().encodeURLParameter())
      }
    }
  }

  private fun StringValuesBuilder.replaceAll(input: Map) {
    input.onEach { (key, value) ->
      if (contains(key)) remove(key)
      when (value) {
        is Iterable<*> -> appendAll(key, value.map { it.toString() })
        else -> append(key, value.toString())
      }
    }
  }

  private val RequestMethod.ktorHttpMethod: HttpMethod
    get() =
      when (this) {
        RequestMethod.DELETE -> HttpMethod.Delete
        RequestMethod.GET -> HttpMethod.Get
        RequestMethod.HEAD -> HttpMethod.Head
        RequestMethod.PATCH -> HttpMethod.Patch
        RequestMethod.PUT -> HttpMethod.Put
        RequestMethod.POST -> HttpMethod.Post
        RequestMethod.OPTIONS -> HttpMethod.Options
      }

  public companion object {
    /** Represents an empty Json object */
    private val EmptyObject = JsonObject(emptyMap())
  }
}