description: A collection of common/useful code examples for Kotlin and Java
---


# Recipes

We've written some recipes that demonstrate how to solve common problems with OkHttp. Read through them to learn about how everything works together. Cut-and-paste these examples freely; that's what they're for.

### Synchronous Get ([.kt][SynchronousGetKotlin], [.java][SynchronousGetJava])

Download a file, print its headers, and print its response body as a string.

// are equal. The signatures are expected to be HEX encoded strings
// according to the AWS S3 signature V4 spec.
func compareSignatureV4(sig1, sig2 string) bool {
	// The CTC using []byte(str) works because the hex encoding
	// is unique for a sequence of bytes. See also compareSignatureV2.
	return subtle.ConstantTimeCompare([]byte(sig1), []byte(sig2)) == 1
}

  ASSERT_TRUE(TF_GetCode(status.get()) == TF_OK) << TF_Message(status.get());
  TFE_DeleteTensorHandle(retval);

  // Custom device: inputs in same custom device works.
  matmul.reset(MatMulOp(context.get(), hcustom0.get(), hcustom0.get()));
  num_retvals = 1;
  executed = false;
  TFE_Execute(matmul.get(), &retval, &num_retvals, status.get());

#### Gateway

Gateway (referring to the [Kubernetes API](http://gateway-api.org/), not the same-named Istio type) works very similarly to [Ingress](#ingress). The Gateway controller also converts Gateway API types into `VirtualService` and `Gateway`, implementing the `ConfigStore` interface.

    SerializableTester.reserializeAndAssert(trimEqualsFoo);
  }

  /**
   * Tests for Predicates.contains(Pattern) and .containsPattern(String). We assume the regex level
   * works, so there are only trivial tests of that aspect. TODO: Fix comment style once annotation
   * stripper is fixed.
   */
  @GwtIncompatible // Predicates.containsPattern
  public void testContainsPattern_apply() {

import junit.framework.TestSuite;

/**
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
public class ImmutableDoubleArrayTest extends TestCase {
  // Test all creation paths very lazily: by assuming asList() works

  public void testOf0() {
    assertThat(ImmutableDoubleArray.of().asList()).isEmpty();
  }

  public void testOf1() {
    assertThat(ImmutableDoubleArray.of(0).asList()).containsExactly(0.0);
  }

```Python
say_hi()  # Oh, no, this throws an error! 😱
```

`name` 🔢 **✔** (🚫 *📦*) ↩️ ⚫️ 🚫 ✔️ 🔢 💲. , `name` 🚫 `None` 💲:

```Python
say_hi(name=None)  # This works, None is valid 🎉
```

👍 📰, 🕐 👆 🔛 🐍 3️⃣.1️⃣0️⃣ 👆 🏆 🚫 ✔️ 😟 🔃 👈, 👆 🔜 💪 🎯 ⚙️ `|` 🔬 🇪🇺 🆎:

```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009c_py310.py!}
```

  TFE_TensorHandleCopyToDevice(h0_task0_new, ctx, remote_device_name, status);
  EXPECT_NE(TF_OK, TF_GetCode(status)) << TF_Message(status);

  // Copying and executing on the new remote device works.
  const char new_remote_device_name[] =
      "/job:worker/replica:0/task:1/device:CPU:0";
  const char new_local_device_name[] =
      "/job:worker/replica:0/task:0/device:CPU:0";

 * if (forceCacheResponse.code() != 504) {
 *   // The resource was cached! Show it.
 * } else {
 *   // The resource was not cached.
 * }
 * ```
 *
 * This technique works even better in situations where a stale response is better than no response.
 * To permit stale cached responses, use the `max-stale` directive with the maximum staleness in
 * seconds:
 *
 * ```java

          RowSortedTable<R, ? extends C, ? extends V> table) {
    /*
     * It's not ? extends R, because it's technically not covariant in R. Specifically,
     * table.rowMap().comparator() could return a comparator that only works for the ? extends R.
     * Collections.unmodifiableSortedMap makes the same distinction.
     */
    return new UnmodifiableRowSortedMap<>(table);
  }

  private static final class UnmodifiableRowSortedMap<