{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

**FastAPI** will **extract** the data for **each field** from the **headers** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

You can see the required headers in the docs UI at `/docs`:

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

            if (field.getType() == int.class) {
                String name = field.getName();
                // Check that constant names follow UPPER_SNAKE_CASE convention
                assertTrue(name.matches("[A-Z_]+"), "Constant " + name + " should follow UPPER_SNAKE_CASE convention");
                // Check that all constants end with _SECURITY_INFO

        // Assert
        assertEquals(10, bytesWritten, "Should write 10 bytes");
        // Check FID (little-endian)
        assertEquals(0x34, dst[0] & 0xFF);
        assertEquals(0x12, dst[1] & 0xFF);
        // Check count
        assertEquals(10, dst[2] & 0xFF);
        assertEquals(0, dst[3] & 0xFF);
        // Check offset
        assertEquals(0x78, dst[4] & 0xFF);
        assertEquals(0x56, dst[5] & 0xFF);
    }

            // Check if the project is being built during this session, and if we can expect any output.
            // There is no need to check if the build has created any outputs, see MNG-2222.
            boolean projectCompiledDuringThisSession =
                    project.hasLifecyclePhase("compile") && COMPILE_PHASE_TYPES.contains(type);

Você pode declarar o tipo de um parâmetro de path na função, usando as anotações de tipo padrão do Python:

{* ../../docs_src/path_params/tutorial002_py39.py hl[7] *}

Neste caso, `item_id` é declarado como um `int`.

/// check | Verifique
Isso fornecerá suporte do editor dentro da sua função, com verificações de erros, preenchimento automático, etc.
///

import java.io.File

class CheckProject(
    model: CIBuildModel,
    functionalTestBucketProvider: FunctionalTestBucketProvider,
) : Project({
        id("Check")
        name = "Check"
        val performanceTestBucketProvider =
            StatisticsBasedPerformanceTestBucketProvider(model, File("performance-test-durations.json"), File("performance-tests-ci.json"))

        params {

You can read more about it in the <a href="https://fastapi.tiangolo.com/fastapi-cli/" target="_blank">FastAPI CLI docs</a>.

</details>

### Check it { #check-it }

Open your browser at <a href="http://127.0.0.1:8000/items/5?q=somequery" class="external-link" target="_blank">http://127.0.0.1:8000/items/5?q=somequery</a>.

You will see the JSON response as:

```JSON

        } finally {
            lock.readLock().unlock();
        }
    }

    /**
     * Check if cache entry is expired
     *
     * @return true if expired
     */
    public boolean isExpired() {
        return System.currentTimeMillis() - lastUpdateTime > maxAge;
    }

    /**
     * Check if cache needs refresh
     *
     * @return true if refresh needed
     */

        Name name = new Name(mockConfig, "TEST", 0x20, null);
        byte[] dst = new byte[100];

        int length = name.writeWireFormat(dst, 0);

        // Check first byte is 0x20
        assertEquals(0x20, dst[0]);

        // Check encoded name (TEST -> encoded as pairs)
        // T = 0x54 -> upper nibble: 0x5 -> 0x46 (F), lower nibble: 0x4 -> 0x45 (E)

        byte[] buffer = new byte[512];
        int written = trans2QueryFSInfo.writeParametersWireFormat(buffer, 0);

        // Should write 2 bytes: information level
        assertEquals(2, written);

        // Check information level (SMB_INFO_ALLOCATION maps to 0x0001)
        int actualInfoLevel = SMBUtil.readInt2(buffer, 0);
        assertEquals(0x0001, actualInfoLevel);
    }

    @Test