com.google.maps.internal.OkHttpPendingResult Maven / Gradle / Ivy
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/*
* Copyright 2014 Google Inc. All rights reserved.
*
*
* 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.google.maps.internal;
import com.google.gson.FieldNamingPolicy;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonSyntaxException;
import com.google.maps.GeolocationApi;
import com.google.maps.ImageResult;
import com.google.maps.PendingResult;
import com.google.maps.errors.ApiException;
import com.google.maps.metrics.RequestMetrics;
import com.google.maps.model.AddressComponentType;
import com.google.maps.model.AddressType;
import com.google.maps.model.Distance;
import com.google.maps.model.Duration;
import com.google.maps.model.Fare;
import com.google.maps.model.LatLng;
import com.google.maps.model.LocationType;
import com.google.maps.model.OpeningHours.Period.OpenClose.DayOfWeek;
import com.google.maps.model.PlaceDetails.Review.AspectRating.RatingType;
import com.google.maps.model.PriceLevel;
import com.google.maps.model.TravelMode;
import com.google.maps.model.VehicleType;
import java.io.IOException;
import java.time.Instant;
import java.time.LocalTime;
import java.time.ZonedDateTime;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.ResponseBody;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A PendingResult backed by a HTTP call executed by OkHttp, a deserialization step using Gson, rate
* limiting and a retry policy.
*
* {@code T} is the type of the result of this pending result, and {@code R} is the type of the
* request.
*/
public class OkHttpPendingResult>
implements PendingResult, Callback {
private final Request request;
private final OkHttpClient client;
private final Class responseClass;
private final FieldNamingPolicy fieldNamingPolicy;
private final Integer maxRetries;
private final RequestMetrics metrics;
private Call call;
private Callback callback;
private long errorTimeOut;
private int retryCounter = 0;
private long cumulativeSleepTime = 0;
private ExceptionsAllowedToRetry exceptionsAllowedToRetry;
private static final Logger LOG = LoggerFactory.getLogger(OkHttpPendingResult.class.getName());
private static final List RETRY_ERROR_CODES = Arrays.asList(500, 503, 504);
/**
* @param request HTTP request to execute.
* @param client The client used to execute the request.
* @param responseClass Model class to unmarshal JSON body content.
* @param fieldNamingPolicy FieldNamingPolicy for unmarshaling JSON.
* @param errorTimeOut Number of milliseconds to re-send erroring requests.
* @param maxRetries Number of times allowed to re-send erroring requests.
* @param exceptionsAllowedToRetry The exceptions to retry.
*/
public OkHttpPendingResult(
Request request,
OkHttpClient client,
Class responseClass,
FieldNamingPolicy fieldNamingPolicy,
long errorTimeOut,
Integer maxRetries,
ExceptionsAllowedToRetry exceptionsAllowedToRetry,
RequestMetrics metrics) {
this.request = request;
this.client = client;
this.responseClass = responseClass;
this.fieldNamingPolicy = fieldNamingPolicy;
this.errorTimeOut = errorTimeOut;
this.maxRetries = maxRetries;
this.exceptionsAllowedToRetry = exceptionsAllowedToRetry;
this.metrics = metrics;
metrics.startNetwork();
this.call = client.newCall(request);
}
@Override
public void setCallback(Callback callback) {
this.callback = callback;
call.enqueue(this);
}
/** Preserve a request/response pair through an asynchronous callback. */
private class QueuedResponse {
private final OkHttpPendingResult request;
private final Response response;
private final IOException e;
public QueuedResponse(OkHttpPendingResult request, Response response) {
this.request = request;
this.response = response;
this.e = null;
}
public QueuedResponse(OkHttpPendingResult request, IOException e) {
this.request = request;
this.response = null;
this.e = e;
}
}
@Override
public T await() throws ApiException, IOException, InterruptedException {
// Handle sleeping for retried requests
if (retryCounter > 0) {
// 0.5 * (1.5 ^ i) represents an increased sleep time of 1.5x per iteration,
// starting at 0.5s when i = 0. The retryCounter will be 1 for the 1st retry,
// so subtract 1 here.
double delaySecs = 0.5 * Math.pow(1.5, retryCounter - 1);
// Generate a jitter value between -delaySecs / 2 and +delaySecs / 2
long delayMillis = (long) (delaySecs * (Math.random() + 0.5) * 1000);
LOG.debug(
String.format(
"Sleeping between errors for %dms (retry #%d, already slept %dms)",
delayMillis, retryCounter, cumulativeSleepTime));
cumulativeSleepTime += delayMillis;
try {
Thread.sleep(delayMillis);
} catch (InterruptedException e) {
// No big deal if we don't sleep as long as intended.
}
}
final BlockingQueue waiter = new ArrayBlockingQueue<>(1);
final OkHttpPendingResult parent = this;
// This callback will be called on another thread, handled by the RateLimitExecutorService.
// Calling call.execute() directly would bypass the rate limiting.
call.enqueue(
new okhttp3.Callback() {
@Override
public void onFailure(Call call, IOException e) {
metrics.endNetwork();
waiter.add(new QueuedResponse(parent, e));
}
@Override
public void onResponse(Call call, Response response) throws IOException {
metrics.endNetwork();
waiter.add(new QueuedResponse(parent, response));
}
});
QueuedResponse r = waiter.take();
if (r.response != null) {
return parseResponse(r.request, r.response);
} else {
metrics.endRequest(r.e, 0, retryCounter);
throw r.e;
}
}
@Override
public T awaitIgnoreError() {
try {
return await();
} catch (Exception e) {
return null;
}
}
@Override
public void cancel() {
call.cancel();
}
@Override
public void onFailure(Call call, IOException ioe) {
metrics.endNetwork();
if (callback != null) {
metrics.endRequest(ioe, 0, retryCounter);
callback.onFailure(ioe);
}
}
@Override
public void onResponse(Call call, Response response) throws IOException {
metrics.endNetwork();
if (callback != null) {
try {
callback.onResult(parseResponse(this, response));
} catch (Exception e) {
callback.onFailure(e);
}
}
}
@SuppressWarnings("unchecked")
private T parseResponse(OkHttpPendingResult request, Response response)
throws ApiException, InterruptedException, IOException {
try {
T result = parseResponseInternal(request, response);
metrics.endRequest(null, response.code(), retryCounter);
return result;
} catch (Exception e) {
metrics.endRequest(e, response.code(), retryCounter);
throw e;
}
}
@SuppressWarnings("unchecked")
private T parseResponseInternal(OkHttpPendingResult request, Response response)
throws ApiException, InterruptedException, IOException {
if (shouldRetry(response)) {
// since we are retrying the request we must close the response
response.close();
// Retry is a blocking method, but that's OK. If we're here, we're either in an await()
// call, which is blocking anyway, or we're handling a callback in a separate thread.
return request.retry();
}
byte[] bytes;
try (ResponseBody body = response.body()) {
bytes = body.bytes();
}
R resp;
String contentType = response.header("Content-Type");
if (contentType != null
&& contentType.startsWith("image")
&& responseClass == ImageResult.Response.class
&& response.code() == 200) {
ImageResult result = new ImageResult(contentType, bytes);
return (T) result;
}
Gson gson =
new GsonBuilder()
.registerTypeAdapter(ZonedDateTime.class, new ZonedDateTimeAdapter())
.registerTypeAdapter(Distance.class, new DistanceAdapter())
.registerTypeAdapter(Duration.class, new DurationAdapter())
.registerTypeAdapter(Fare.class, new FareAdapter())
.registerTypeAdapter(LatLng.class, new LatLngAdapter())
.registerTypeAdapter(
AddressComponentType.class,
new SafeEnumAdapter(AddressComponentType.UNKNOWN))
.registerTypeAdapter(
AddressType.class, new SafeEnumAdapter(AddressType.UNKNOWN))
.registerTypeAdapter(
TravelMode.class, new SafeEnumAdapter(TravelMode.UNKNOWN))
.registerTypeAdapter(
LocationType.class, new SafeEnumAdapter(LocationType.UNKNOWN))
.registerTypeAdapter(
RatingType.class, new SafeEnumAdapter(RatingType.UNKNOWN))
.registerTypeAdapter(
VehicleType.class, new SafeEnumAdapter(VehicleType.OTHER))
.registerTypeAdapter(DayOfWeek.class, new DayOfWeekAdapter())
.registerTypeAdapter(PriceLevel.class, new PriceLevelAdapter())
.registerTypeAdapter(Instant.class, new InstantAdapter())
.registerTypeAdapter(LocalTime.class, new LocalTimeAdapter())
.registerTypeAdapter(GeolocationApi.Response.class, new GeolocationResponseAdapter())
.setFieldNamingPolicy(fieldNamingPolicy)
.create();
// Attempt to de-serialize before checking the HTTP status code, as there may be JSON in the
// body that we can use to provide a more descriptive exception.
try {
resp = gson.fromJson(new String(bytes, "utf8"), responseClass);
} catch (JsonSyntaxException e) {
// Check HTTP status for a more suitable exception
if (!response.isSuccessful()) {
// Some of the APIs return 200 even when the API request fails, as long as the transport
// mechanism succeeds. In these cases, INVALID_RESPONSE, etc are handled by the Gson
// parsing.
throw new IOException(
String.format("Server Error: %d %s", response.code(), response.message()));
}
// Otherwise just cough up the syntax exception.
throw e;
}
if (resp.successful()) {
// Return successful responses
return resp.getResult();
} else {
ApiException e = resp.getError();
if (shouldRetry(e)) {
return request.retry();
} else {
throw e;
}
}
}
private T retry() throws ApiException, InterruptedException, IOException {
retryCounter++;
LOG.info("Retrying request. Retry #" + retryCounter);
metrics.startNetwork();
this.call = client.newCall(request);
return this.await();
}
private boolean shouldRetry(Response response) {
return RETRY_ERROR_CODES.contains(response.code())
&& cumulativeSleepTime < errorTimeOut
&& (maxRetries == null || retryCounter < maxRetries);
}
private boolean shouldRetry(ApiException exception) {
return exceptionsAllowedToRetry.contains(exception.getClass())
&& cumulativeSleepTime < errorTimeOut
&& (maxRetries == null || retryCounter < maxRetries);
}
}