okhttp3.internal.http.RouteSelector Maven / Gradle / Ivy
/*
* Copyright (C) 2012 Square, 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 okhttp3.internal.http;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.SocketAddress;
import java.net.SocketException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.NoSuchElementException;
import okhttp3.Address;
import okhttp3.HttpUrl;
import okhttp3.Route;
import okhttp3.internal.RouteDatabase;
/**
* Selects routes to connect to an origin server. Each connection requires a choice of proxy server,
* IP address, and TLS mode. Connections may also be recycled.
*/
public final class RouteSelector {
private final Address address;
private final RouteDatabase routeDatabase;
/* The most recently attempted route. */
private Proxy lastProxy;
private InetSocketAddress lastInetSocketAddress;
/* State for negotiating the next proxy to use. */
private List proxies = Collections.emptyList();
private int nextProxyIndex;
/* State for negotiating the next socket address to use. */
private List inetSocketAddresses = Collections.emptyList();
private int nextInetSocketAddressIndex;
/* State for negotiating failed routes */
private final List postponedRoutes = new ArrayList<>();
public RouteSelector(Address address, RouteDatabase routeDatabase) {
this.address = address;
this.routeDatabase = routeDatabase;
resetNextProxy(address.url(), address.proxy());
}
/**
* Returns true if there's another route to attempt. Every address has at least one route.
*/
public boolean hasNext() {
return hasNextInetSocketAddress()
|| hasNextProxy()
|| hasNextPostponed();
}
public Route next() throws IOException {
// Compute the next route to attempt.
if (!hasNextInetSocketAddress()) {
if (!hasNextProxy()) {
if (!hasNextPostponed()) {
throw new NoSuchElementException();
}
return nextPostponed();
}
lastProxy = nextProxy();
}
lastInetSocketAddress = nextInetSocketAddress();
Route route = new Route(address, lastProxy, lastInetSocketAddress);
if (routeDatabase.shouldPostpone(route)) {
postponedRoutes.add(route);
// We will only recurse in order to skip previously failed routes. They will be tried last.
return next();
}
return route;
}
/**
* Clients should invoke this method when they encounter a connectivity failure on a connection
* returned by this route selector.
*/
public void connectFailed(Route failedRoute, IOException failure) {
if (failedRoute.proxy().type() != Proxy.Type.DIRECT && address.proxySelector() != null) {
// Tell the proxy selector when we fail to connect on a fresh connection.
address.proxySelector().connectFailed(
address.url().uri(), failedRoute.proxy().address(), failure);
}
routeDatabase.failed(failedRoute);
}
/** Prepares the proxy servers to try. */
private void resetNextProxy(HttpUrl url, Proxy proxy) {
if (proxy != null) {
// If the user specifies a proxy, try that and only that.
proxies = Collections.singletonList(proxy);
} else {
// Try each of the ProxySelector choices until one connection succeeds. If none succeed
// then we'll try a direct connection below.
proxies = new ArrayList<>();
List selectedProxies = address.proxySelector().select(url.uri());
if (selectedProxies != null) proxies.addAll(selectedProxies);
// Finally try a direct connection. We only try it once!
proxies.removeAll(Collections.singleton(Proxy.NO_PROXY));
proxies.add(Proxy.NO_PROXY);
}
nextProxyIndex = 0;
}
/** Returns true if there's another proxy to try. */
private boolean hasNextProxy() {
return nextProxyIndex < proxies.size();
}
/** Returns the next proxy to try. May be PROXY.NO_PROXY but never null. */
private Proxy nextProxy() throws IOException {
if (!hasNextProxy()) {
throw new SocketException("No route to " + address.url().host()
+ "; exhausted proxy configurations: " + proxies);
}
Proxy result = proxies.get(nextProxyIndex++);
resetNextInetSocketAddress(result);
return result;
}
/** Prepares the socket addresses to attempt for the current proxy or host. */
private void resetNextInetSocketAddress(Proxy proxy) throws IOException {
// Clear the addresses. Necessary if getAllByName() below throws!
inetSocketAddresses = new ArrayList<>();
String socketHost;
int socketPort;
if (proxy.type() == Proxy.Type.DIRECT || proxy.type() == Proxy.Type.SOCKS) {
socketHost = address.url().host();
socketPort = address.url().port();
} else {
SocketAddress proxyAddress = proxy.address();
if (!(proxyAddress instanceof InetSocketAddress)) {
throw new IllegalArgumentException(
"Proxy.address() is not an " + "InetSocketAddress: " + proxyAddress.getClass());
}
InetSocketAddress proxySocketAddress = (InetSocketAddress) proxyAddress;
socketHost = getHostString(proxySocketAddress);
socketPort = proxySocketAddress.getPort();
}
if (socketPort < 1 || socketPort > 65535) {
throw new SocketException("No route to " + socketHost + ":" + socketPort
+ "; port is out of range");
}
if (proxy.type() == Proxy.Type.SOCKS) {
inetSocketAddresses.add(InetSocketAddress.createUnresolved(socketHost, socketPort));
} else {
// Try each address for best behavior in mixed IPv4/IPv6 environments.
List addresses = address.dns().lookup(socketHost);
for (int i = 0, size = addresses.size(); i < size; i++) {
InetAddress inetAddress = addresses.get(i);
inetSocketAddresses.add(new InetSocketAddress(inetAddress, socketPort));
}
}
nextInetSocketAddressIndex = 0;
}
/**
* Obtain a "host" from an {@link InetSocketAddress}. This returns a string containing either an
* actual host name or a numeric IP address.
*/
// Visible for testing
static String getHostString(InetSocketAddress socketAddress) {
InetAddress address = socketAddress.getAddress();
if (address == null) {
// The InetSocketAddress was specified with a string (either a numeric IP or a host name). If
// it is a name, all IPs for that name should be tried. If it is an IP address, only that IP
// address should be tried.
return socketAddress.getHostName();
}
// The InetSocketAddress has a specific address: we should only try that address. Therefore we
// return the address and ignore any host name that may be available.
return address.getHostAddress();
}
/** Returns true if there's another socket address to try. */
private boolean hasNextInetSocketAddress() {
return nextInetSocketAddressIndex < inetSocketAddresses.size();
}
/** Returns the next socket address to try. */
private InetSocketAddress nextInetSocketAddress() throws IOException {
if (!hasNextInetSocketAddress()) {
throw new SocketException("No route to " + address.url().host()
+ "; exhausted inet socket addresses: " + inetSocketAddresses);
}
return inetSocketAddresses.get(nextInetSocketAddressIndex++);
}
/** Returns true if there is another postponed route to try. */
private boolean hasNextPostponed() {
return !postponedRoutes.isEmpty();
}
/** Returns the next postponed route to try. */
private Route nextPostponed() {
return postponedRoutes.remove(0);
}
}