OkHttp ====== See the [project website][okhttp] for documentation and APIs. HTTP is the way modern applications network. It’s how we exchange data & media. Doing HTTP efficiently makes your stuff load faster and saves bandwidth. OkHttp is an HTTP client that’s efficient by default: * HTTP/2 support allows all requests to the same host to share a socket. * Connection pooling reduces request latency (if HTTP/2 isn’t available). * Transparent GZIP shrinks download sizes. * Response caching avoids the network completely for repeat requests. OkHttp perseveres when the network is troublesome: it will silently recover from common connection problems. If your service has multiple IP addresses, OkHttp will attempt alternate addresses if the first connect fails. This is necessary for IPv4+IPv6 and services hosted in redundant data centers. OkHttp supports modern TLS features (TLS 1.3, ALPN, certificate pinning). It can be configured to fall back for broad connectivity. Using OkHttp is easy. Its request/response API is designed with fluent builders and immutability. It supports both synchronous blocking calls and async calls with callbacks. Get a URL --------- This program downloads a URL and prints its contents as a string. [Full source][get_example]. ```java OkHttpClient client = new OkHttpClient(); String run(String url) throws IOException { Request request = new Request.Builder() .url(url) .build(); try (Response response = client.newCall(request).execute()) { return response.body().string(); } } ``` Post to a Server ---------------- This program posts data to a service. [Full source][post_example]. ```java public static final MediaType JSON = MediaType.get("application/json"); OkHttpClient client = new OkHttpClient(); String post(String url, String json) throws IOException { RequestBody body = RequestBody.create(json, JSON); Request request = new Request.Builder() .url(url) .post(body) .build(); try (Response response = client.newCall(request).execute()) { return response.body().string(); } } ``` Further examples are on the [OkHttp Recipes page][recipes]. Requirements ------------ OkHttp works on Android 5.0+ (API level 21+) and Java 8+. OkHttp depends on [Okio][okio] for high-performance I/O and the [Kotlin standard library][kotlin]. Both are small libraries with strong backward-compatibility. We highly recommend you keep OkHttp up-to-date. As with auto-updating web browsers, staying current with HTTPS clients is an important defense against potential security problems. [We track][tls_history] the dynamic TLS ecosystem and adjust OkHttp to improve connectivity and security. OkHttp uses your platform's built-in TLS implementation. On Java platforms OkHttp also supports [Conscrypt][conscrypt], which integrates [BoringSSL](https://github.com/google/boringssl) with Java. OkHttp will use Conscrypt if it is the first security provider: ```java Security.insertProviderAt(Conscrypt.newProvider(), 1); ``` The OkHttp `3.12.x` branch supports Android 2.3+ (API level 9+) and Java 7+. These platforms lack support for TLS 1.2 and should not be used. Releases -------- Our [change log][changelog] has release history. The latest release is available on [Maven Central](https://search.maven.org/artifact/com.squareup.okhttp3/okhttp/4.12.0/jar). ```kotlin implementation("com.squareup.okhttp3:okhttp:4.12.0") ``` Snapshot builds are [available][snap]. [R8 and ProGuard][r8_proguard] rules are available. Also, we have a [bill of materials (BOM)][bom] available to help you keep OkHttp artifacts up to date and be sure about version compatibility. ```kotlin dependencies { // define a BOM and its version implementation(platform("com.squareup.okhttp3:okhttp-bom:4.12.0")) // define any required OkHttp artifacts without version implementation("com.squareup.okhttp3:okhttp") implementation("com.squareup.okhttp3:logging-interceptor") } ``` MockWebServer ------------- OkHttp includes a library for testing HTTP, HTTPS, and HTTP/2 clients. The latest release is available on [Maven Central](https://search.maven.org/artifact/com.squareup.okhttp3/mockwebserver/4.12.0/jar). ```kotlin testImplementation("com.squareup.okhttp3:mockwebserver:4.12.0") ``` GraalVM Native Image -------------------- Building your native images with Graal https://www.graalvm.org/ should work automatically. This is not currently in a final released version, so `5.0.0-alpha.2` should be used. Please report any bugs or workarounds you find. See the okcurl module for an example build. ```shell $ ./gradlew okcurl:nativeImage $ ./okcurl/build/graal/okcurl https://httpbin.org/get ``` License ------- ``` Copyright 2019 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. ``` [bom]: https://docs.gradle.org/6.2/userguide/platforms.html#sub:bom_import [changelog]: https://square.github.io/okhttp/changelog/ [conscrypt]: https://github.com/google/conscrypt/ [get_example]: https://raw.github.com/square/okhttp/master/samples/guide/src/main/java/okhttp3/guide/GetExample.java [kotlin]: https://kotlinlang.org/ [okhttp3_pro]: https://raw.githubusercontent.com/square/okhttp/master/okhttp/src/main/resources/META-INF/proguard/okhttp3.pro [okhttp_312x]: https://github.com/square/okhttp/tree/okhttp_3.12.x [okhttp]: https://square.github.io/okhttp/ [okio]: https://github.com/square/okio [post_example]: https://raw.github.com/square/okhttp/master/samples/guide/src/main/java/okhttp3/guide/PostExample.java [r8_proguard]: https://square.github.io/okhttp/features/r8_proguard/ [recipes]: https://square.github.io/okhttp/recipes/ [snap]: https://s01.oss.sonatype.org/content/repositories/snapshots/ [tls_history]: https://square.github.io/okhttp/tls_configuration_history/