Removes okhttp support (#1258)

Fixes gh-1205

Author: spencergibb

docs/modules/ROOT/pages/spring-cloud-openfeign.adoc

@@ -140,12 +140,10 @@ If none of them is on the classpath, the default Feign client is used.
 
 NOTE: `spring-cloud-starter-openfeign` supports `spring-cloud-starter-loadbalancer`. However, as is an optional dependency, you need to make sure it has been added to your project if you want to use it.
 
-To use OkHttpClient-backed Feign clients and Http2Client Feign clients, make sure that the client you want to use is on the classpath and set `spring.cloud.openfeign.okhttp.enabled` or `spring.cloud.openfeign.http2client.enabled` to `true` respectively.
-
 When it comes to the Apache HttpClient 5-backed Feign clients, it's enough to ensure HttpClient 5 is on the classpath, but you can still disable its use for Feign Clients by setting  `spring.cloud.openfeign.httpclient.hc5.enabled` to `false`.
 You can customize the HTTP client used by providing a bean of either `org.apache.hc.client5.http.impl.classic.CloseableHttpClient` when using Apache HC5.
 
-You can further customise http clients by setting values in the `spring.cloud.openfeign.httpclient.xxx` properties. The ones prefixed just with `httpclient` will work for all the clients, the ones prefixed with `httpclient.hc5` to Apache HttpClient 5, the ones prefixed with `httpclient.okhttp` to OkHttpClient and the ones prefixed with `httpclient.http2` to Http2Client. You can find a full list of properties you can customise in the appendix.
+You can further customise http clients by setting values in the `spring.cloud.openfeign.httpclient.xxx` properties. The ones prefixed just with `httpclient` will work for all the clients, the ones prefixed with `httpclient.hc5` to Apache HttpClient 5, and the ones prefixed with `httpclient.http2` to Http2Client. You can find a full list of properties you can customise in the appendix.
 If you can not configure Apache HttpClient 5 by using properties, there is an `HttpClient5FeignConfiguration.HttpClientBuilderCustomizer` interface for programmatic configuration.
 
 TIP: Apache HTTP Components `5.4` have changed defaults in the HttpClient relating to HTTP/1.1 TLS upgrades. Most proxy servers handle upgrades without issue, however, you may encounter issues with Envoy or Istio. If you need to restore previous behaviour, you can use `HttpClient5FeignConfiguration.HttpClientBuilderCustomizer` to do it, as shown in the example below.
@@ -613,8 +611,6 @@ These properties allow you to be selective about the compressed media types and
 When the request matches the mime type set in `spring.cloud.openfeign.compression.request.mime-types` and the size set in `spring.cloud.openfeign.compression.request.min-request-size`, `spring.cloud.openfeign.compression.request.enabled=true` results in compression headers being added to the request.
 The functionality of the headers is to signal to the server that a compressed body is expected by the client. It is the responsibility of the server-side app to provide the compressed body based on the headers provided by the client.
 
-TIP: Since the OkHttpClient uses "transparent" compression, that is disabled if the `content-encoding` or `accept-encoding` header is present, we do not enable compression when `feign.okhttp.OkHttpClient` is present on the classpath and `spring.cloud.openfeign.okhttp.enabled` is set to `true`.
-
 [[feign-logging]]
 === Feign logging
 

docs/modules/ROOT/partials/_configprops.adoc

@@ -96,14 +96,12 @@
 |spring.cloud.openfeign.httpclient.max-connections | `+++200+++` | 
 |spring.cloud.openfeign.httpclient.max-connections-per-route | `+++50+++` | 
 |spring.cloud.openfeign.httpclient.ok-http.protocols |  | Configure the protocols used by this client to communicate with remote servers. Uses {@link String} values of {@link Protocol}.
-|spring.cloud.openfeign.httpclient.ok-http.read-timeout | `+++60s+++` | {@link OkHttpClient} read timeout; defaults to 60 seconds.
-|spring.cloud.openfeign.httpclient.time-to-live | `+++900+++` | 
+|spring.cloud.openfeign.httpclient.time-to-live | `+++900+++` |
 |spring.cloud.openfeign.httpclient.time-to-live-unit | `+++seconds+++` | 
 |spring.cloud.openfeign.lazy-attributes-resolution | `+++false+++` | Switches @FeignClient attributes resolution mode to lazy.
 |spring.cloud.openfeign.micrometer.enabled | `+++true+++` | Enables Micrometer capabilities for Feign.
 |spring.cloud.openfeign.oauth2.clientRegistrationId |  | Provides a clientId to be used with OAuth2.
 |spring.cloud.openfeign.oauth2.enabled | `+++false+++` | Enables feign interceptor for managing oauth2 access token.
-|spring.cloud.openfeign.okhttp.enabled | `+++false+++` | Enables the use of the OK HTTP Client by Feign.
 |spring.cloud.refresh.additional-property-sources-to-retain |  | Additional property sources to retain during a refresh. Typically only system property sources are retained. This property allows property sources, such as property sources created by EnvironmentPostProcessors to be retained as well.
 |spring.cloud.refresh.enabled | `+++true+++` | Enables autoconfiguration for the refresh scope and associated features.
 |spring.cloud.refresh.extra-refreshable | `+++true+++` | Additional bean names or class names for beans to post process into refresh scope.
@@ -114,4 +112,4 @@
 |spring.cloud.service-registry.auto-registration.register-management | `+++true+++` | Whether to register the management as a service. Defaults to true.
 |spring.cloud.util.enabled | `+++true+++` | Enables creation of Spring Cloud utility beans.
 
-|===
+|===

spring-cloud-openfeign-core/pom.xml

@@ -134,21 +134,11 @@
 			<artifactId>feign-hc5</artifactId>
 			<optional>true</optional>
 		</dependency>
-		<dependency>
-			<groupId>io.github.openfeign</groupId>
-			<artifactId>feign-okhttp</artifactId>
-			<optional>true</optional>
-		</dependency>
 		<dependency>
 			<groupId>io.github.openfeign</groupId>
 			<artifactId>feign-java11</artifactId>
 			<optional>true</optional>
 		</dependency>
-		<dependency>
-			<groupId>com.squareup.okhttp3</groupId>
-			<artifactId>okhttp</artifactId>
-			<optional>true</optional>
-		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-autoconfigure-processor</artifactId>

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/FeignAutoConfiguration.java

@@ -18,22 +18,9 @@
 
 import java.lang.reflect.Method;
 import java.net.http.HttpClient;
-import java.security.KeyManagementException;
-import java.security.NoSuchAlgorithmException;
-import java.security.cert.X509Certificate;
-import java.time.Duration;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
-import java.util.concurrent.TimeUnit;
-import java.util.stream.Collectors;
-
-import javax.net.ssl.HostnameVerifier;
-import javax.net.ssl.SSLContext;
-import javax.net.ssl.SSLSession;
-import javax.net.ssl.SSLSocketFactory;
-import javax.net.ssl.TrustManager;
-import javax.net.ssl.X509TrustManager;
 
 import feign.Capability;
 import feign.Client;
@@ -42,10 +29,6 @@
 import feign.Target;
 import feign.hc5.ApacheHttp5Client;
 import feign.http2client.Http2Client;
-import feign.okhttp.OkHttpClient;
-import jakarta.annotation.PreDestroy;
-import okhttp3.ConnectionPool;
-import okhttp3.Protocol;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
@@ -231,121 +214,6 @@ public String resolveCircuitBreakerName(String feignClientName, Target<?> target
 
 	}
 
-	// the following configuration is for alternate feign clients if
-	// SC loadbalancer is not on the class path.
-	// see corresponding configurations in FeignLoadBalancerAutoConfiguration
-	// for load-balanced clients.
-	@Configuration(proxyBeanMethods = false)
-	@ConditionalOnClass(OkHttpClient.class)
-	@ConditionalOnMissingBean(okhttp3.OkHttpClient.class)
-	@ConditionalOnProperty("spring.cloud.openfeign.okhttp.enabled")
-	protected static class OkHttpFeignConfiguration {
-
-		private okhttp3.OkHttpClient okHttpClient;
-
-		@Bean
-		@ConditionalOnMissingBean
-		public okhttp3.OkHttpClient.Builder okHttpClientBuilder() {
-			return new okhttp3.OkHttpClient.Builder();
-		}
-
-		@Bean
-		@ConditionalOnMissingBean(ConnectionPool.class)
-		public ConnectionPool httpClientConnectionPool(FeignHttpClientProperties httpClientProperties) {
-			int maxTotalConnections = httpClientProperties.getMaxConnections();
-			long timeToLive = httpClientProperties.getTimeToLive();
-			TimeUnit ttlUnit = httpClientProperties.getTimeToLiveUnit();
-			return new ConnectionPool(maxTotalConnections, timeToLive, ttlUnit);
-		}
-
-		@Bean
-		public okhttp3.OkHttpClient okHttpClient(okhttp3.OkHttpClient.Builder builder, ConnectionPool connectionPool,
-				FeignHttpClientProperties httpClientProperties) {
-			boolean followRedirects = httpClientProperties.isFollowRedirects();
-			int connectTimeout = httpClientProperties.getConnectionTimeout();
-			boolean disableSslValidation = httpClientProperties.isDisableSslValidation();
-			Duration readTimeout = httpClientProperties.getOkHttp().getReadTimeout();
-			List<Protocol> protocols = httpClientProperties.getOkHttp()
-				.getProtocols()
-				.stream()
-				.map(Protocol::valueOf)
-				.collect(Collectors.toList());
-			if (disableSslValidation) {
-				disableSsl(builder);
-			}
-			this.okHttpClient = builder.connectTimeout(connectTimeout, TimeUnit.MILLISECONDS)
-				.followRedirects(followRedirects)
-				.readTimeout(readTimeout)
-				.connectionPool(connectionPool)
-				.protocols(protocols)
-				.build();
-			return this.okHttpClient;
-		}
-
-		private void disableSsl(okhttp3.OkHttpClient.Builder builder) {
-			try {
-				X509TrustManager disabledTrustManager = new DisableValidationTrustManager();
-				TrustManager[] trustManagers = new TrustManager[1];
-				trustManagers[0] = disabledTrustManager;
-				SSLContext sslContext = SSLContext.getInstance("SSL");
-				sslContext.init(null, trustManagers, new java.security.SecureRandom());
-				SSLSocketFactory disabledSSLSocketFactory = sslContext.getSocketFactory();
-				builder.sslSocketFactory(disabledSSLSocketFactory, disabledTrustManager);
-				builder.hostnameVerifier(new TrustAllHostnames());
-			}
-			catch (NoSuchAlgorithmException | KeyManagementException e) {
-				LOG.warn("Error setting SSLSocketFactory in OKHttpClient", e);
-			}
-		}
-
-		@PreDestroy
-		public void destroy() {
-			if (this.okHttpClient != null) {
-				this.okHttpClient.dispatcher().executorService().shutdown();
-				this.okHttpClient.connectionPool().evictAll();
-			}
-		}
-
-		@Bean
-		@ConditionalOnMissingBean(Client.class)
-		public Client feignClient(okhttp3.OkHttpClient client) {
-			return new OkHttpClient(client);
-		}
-
-		/**
-		 * A {@link X509TrustManager} that does not validate SSL certificates.
-		 */
-		class DisableValidationTrustManager implements X509TrustManager {
-
-			@Override
-			public void checkClientTrusted(X509Certificate[] x509Certificates, String s) {
-			}
-
-			@Override
-			public void checkServerTrusted(X509Certificate[] x509Certificates, String s) {
-			}
-
-			@Override
-			public X509Certificate[] getAcceptedIssuers() {
-				return new X509Certificate[0];
-			}
-
-		}
-
-		/**
-		 * A {@link HostnameVerifier} that does not validate any hostnames.
-		 */
-		class TrustAllHostnames implements HostnameVerifier {
-
-			@Override
-			public boolean verify(String s, SSLSession sslSession) {
-				return true;
-			}
-
-		}
-
-	}
-
 	// the following configuration is for alternate feign clients if
 	// SC loadbalancer is not on the class path.
 	// see corresponding configurations in FeignLoadBalancerAutoConfiguration

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/encoding/FeignAcceptGzipEncodingAutoConfiguration.java

@@ -26,7 +26,6 @@
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.openfeign.FeignAutoConfiguration;
 import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
 
 /**
@@ -41,9 +40,6 @@
 @ConditionalOnClass(Feign.class)
 @ConditionalOnBean(Client.class)
 @ConditionalOnProperty("spring.cloud.openfeign.compression.response.enabled")
-// The OK HTTP client uses "transparent" compression.
-// If the accept-encoding header is present, it disables transparent compression.
-@Conditional(OkHttpFeignClientBeanMissingCondition.class)
 @AutoConfigureAfter(FeignAutoConfiguration.class)
 public class FeignAcceptGzipEncodingAutoConfiguration {
 

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/encoding/FeignContentGzipEncodingAutoConfiguration.java

@@ -24,7 +24,6 @@
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.openfeign.FeignAutoConfiguration;
 import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
 
 /**
@@ -37,9 +36,6 @@
 @Configuration(proxyBeanMethods = false)
 @EnableConfigurationProperties(FeignClientEncodingProperties.class)
 @ConditionalOnClass(Feign.class)
-// The OK HTTP client uses "transparent" compression.
-// If the content-encoding header is present, it disables transparent compression.
-@Conditional(OkHttpFeignClientBeanMissingCondition.class)
 @ConditionalOnProperty("spring.cloud.openfeign.compression.request.enabled")
 @AutoConfigureAfter(FeignAutoConfiguration.class)
 public class FeignContentGzipEncodingAutoConfiguration {

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/encoding/OkHttpFeignClientBeanMissingCondition.java

@@ -53,8 +53,8 @@
 // Order is important here, last should be the default, first should be optional
 // see
 // https://github.com/spring-cloud/spring-cloud-netflix/issues/2086#issuecomment-316281653
-@Import({ OkHttpFeignLoadBalancerConfiguration.class, HttpClient5FeignLoadBalancerConfiguration.class,
-		Http2ClientFeignLoadBalancerConfiguration.class, DefaultFeignLoadBalancerConfiguration.class })
+@Import({ HttpClient5FeignLoadBalancerConfiguration.class, Http2ClientFeignLoadBalancerConfiguration.class,
+		DefaultFeignLoadBalancerConfiguration.class })
 public class FeignLoadBalancerAutoConfiguration {
 
 	@Bean