<div class="screenshot">
<img src="/img/tutorial/query-param-models/image01.png">
</div>

## Forbid Extra Query Parameters { #forbid-extra-query-parameters }

In some special use cases (probably not very common), you might want to **restrict** the query parameters that you want to receive.

You can use Pydantic's model configuration to `forbid` any `extra` fields:

 * parameter word (the session identifier) is written in little‑endian form
 * and that the {@code toString} helper contains the expected values.
 *
 * <p>The tests also exercise edge cases such as negative (wrap‑around) session
 * identifiers and confirm that the writer does not alter any internal state.
 *</p>
 */
@ExtendWith(MockitoExtension.class)
class SmbComFindClose2Test {

    @Mock

		// Short; unchanged:
		{`C:\short.txt`, `C:\short.txt`},
		{`C:\`, `C:\`},
		{`C:`, `C:`},
		// The "long" substring is replaced by a looooooong
		// string which triggers the rewriting. Except in the
		// cases below where it doesn't.
		{`C:\long\foo.txt`, `\\?\C:\long\foo.txt`},
		{`C:/long/foo.txt`, `\\?\C:\long\foo.txt`},
		{`C:\long\foo\\bar\.\baz\\`, `\\?\C:\long\foo\bar\baz`},
		{`\\unc\path`, `\\unc\path`},

   * will return {@code Double.MAX_VALUE}, not {@code Double.POSITIVE_INFINITY}.
   *
   * <p>For the case of {@link RoundingMode#HALF_EVEN}, this implementation uses the IEEE 754
   * default rounding mode: if the two nearest representable values are equally near, the one with
   * the least significant bit zero is chosen. (In such cases, both of the nearest representable

# JSON Compatible Encoder { #json-compatible-encoder }

There are some cases where you might need to convert a data type (like a Pydantic model) to something compatible with JSON (like a `dict`, `list`, etc).

For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder` { #using-the-jsonable-encoder }

### Certificate Renewal { #certificate-renewal }

At some point in the future, each certificate would **expire** (about 3 months after acquiring it).

And then, there would be another program (in some cases it's another program, in some cases it could be the same TLS Termination Proxy) that would talk to Let's Encrypt, and renew the certificate(s).

In these cases you can use `root_path` to configure your application.

The `root_path` is a mechanism provided by the ASGI specification (that FastAPI is built on, through Starlette).

The `root_path` is used to handle these specific cases.

And it's also used internally when mounting sub-applications.

        "HashMap w/out null values",
        ALLOWS_NULL_KEYS);
  }

  /**
   * Map generator that verifies that {@code setUp()} methods are called in all the test cases. The
   * {@code setUpRan} parameter is set true by the {@code setUp} that every test case is supposed to
   * have registered, and set false by the {@code tearDown}. We use a dynamic proxy to intercept all

    assertFalse(
        "after removeAll(e), a collection should not contain e even "
            + "if it initially contained e more than once.",
        getList().contains(duplicate));
  }

  // All other cases are covered by CollectionRemoveAllTester.

import org.apache.maven.wagon.events.TransferListener;
import org.apache.maven.wagon.providers.file.FileWagon;
import org.apache.maven.wagon.resource.Resource;

/**
 * Wagon used for test cases that annotate some methods. Note that this is not a thread-safe implementation.
 */
public class TestFileWagon extends FileWagon {
    private TestTransferListener testTransferListener;
    private boolean insideGet;