[AccessHeadersJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/AccessHeaders.java
 [AccessHeadersKotlin]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/kt/AccessHeaders.kt
 [PostStringJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PostString.java

# How To - Recipes { #how-to-recipes }

Here you will see different recipes or "how to" guides for **several topics**.

Most of these ideas would be more or less **independent**, and in most cases you should only need to study them if they apply directly to **your project**.

If something seems interesting and useful to your project, go ahead and check it, but otherwise, you might probably just skip them.

/// tip

private fun mainFiles(): List<File> {
  val directories =
    listOf(
      "$prefix/samples/guide/src/main/java/okhttp3/guide",
      "$prefix/samples/guide/src/main/java/okhttp3/recipes",
      "$prefix/samples/guide/src/main/java/okhttp3/recipes/kt",
    ).map { File(it) }

  return directories.flatMap {
    it
      .listFiles()
      .orEmpty()
      .filter { f -> f.isFile }
      .toList()
  }
}

 * 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.recipes;

import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;
import com.squareup.moshi.Types;
import java.io.IOException;
import java.util.LinkedHashMap;
import java.util.Map;

# General - How To - Recipes { #general-how-to-recipes }

Here are several pointers to other places in the docs, for general or frequent questions.

## Filter Data - Security { #filter-data-security }

To ensure that you don't return more data than you should, read the docs for [Tutorial - Response Model - Return Type](../tutorial/response-model.md).

package okhttp3.recipes;

import java.util.concurrent.TimeUnit;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.WebSocket;
import okhttp3.WebSocketListener;
import okio.ByteString;

public final class WebSocketEcho extends WebSocketListener {
  private void run() {
    OkHttpClient client = new OkHttpClient.Builder()
        .readTimeout(0,  TimeUnit.MILLISECONDS)
        .build();

 [CustomTrustJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/CustomTrust.java
 [CustomTrustKotlin]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/kt/CustomTrust.kt
 [CertificatePinningJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/CertificatePinning.java

      .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+.

On Android, OkHttp uses [AndroidX Startup][androidx_startup]. If you disable the initializer in the manifest,

defines the meaning of the FIPS version alias x, listing
the exact version to use.

The zip files are created by cmd/go/internal/fips140/mkzip.go.
The fips140.sum file lists checksums for the zip files.

 * 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.recipes;

import java.io.IOException;
import java.security.cert.Certificate;
import java.util.Collections;
import java.util.Set;
import okhttp3.CertificatePinner;
import okhttp3.Interceptor;
import okhttp3.OkHttpClient;