# Dependencies - `Depends()` and `Security()`

## `Depends()`

Dependencies are handled mainly with the special function `Depends()` that takes a callable.

Here is the reference for it and its parameters.

You can import it directly from `fastapi`:

```python
from fastapi import Depends
```

::: fastapi.Depends

## `Security()`

            retValue = decode(retValue);
            // special case: if omitted // on protocol, keep path as is
            if (retValue.startsWith("//")) {
                retValue = retValue.substring(2);

                if (retValue.length() >= 2 && (retValue.charAt(1) == '|' || retValue.charAt(1) == ':')) {
                    // special case: if there is a windows drive letter, then keep the original return value

# Test generating the javadoc jars
./gradlew publishToMavenLocal -DRELEASE_SIGNING_ENABLED=false

# Generate the API docs
./gradlew dokkaHtmlMultiModule

mv ./build/dokka/htmlMultiModule docs/4.x

# Copy in special files that GitHub wants in the project root.
cat README.md | grep -v 'project website' > docs/index.md
cp CHANGELOG.md docs/changelogs/changelog.md
cp CONTRIBUTING.md docs/contribute/contributing.md

# Build the site locally

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

/// info | Información

Ten en cuenta que, como los **navegadores manejan las cookies** de maneras especiales y detrás de escenas, **no** permiten fácilmente que **JavaScript** las toque.

Si vas a la **UI de la documentación de la API** en `/docs` podrás ver la **documentación** de las cookies para tus *path operations*.

    // my best guess is that the jdk authors have spent more time optimizing that callpath than this
    // one. (StringCoding$StringDecoder vs. StreamDecoder).  StringCoding has a ton of special cases
    // theoretically we could duplicate all that logic here to try to beat 'new String' or at least
    // come close.
    USING_DECODER_WITH_SIZE_HINT {
      @Override

are the reason we use the ordinary General Public License for many
libraries.  However, the Lesser license provides advantages in certain
special circumstances.

  For example, on rare occasions, there may be a special need to
encourage the widest possible use of a certain library, so that it becomes
a de-facto standard.  To achieve this, non-free programs must be

    public void test_isUrlChar_commonSpecialChars() {
        // Test common special characters
        assertTrue(CharUtil.isUrlChar('.'));
        assertTrue(CharUtil.isUrlChar('-'));
        assertTrue(CharUtil.isUrlChar('*'));
        assertTrue(CharUtil.isUrlChar('_'));
    }

    public void test_isUrlChar_urlSpecialChars() {
        // Test URL-specific special characters
        assertTrue(CharUtil.isUrlChar(':'));

        assertEquals(mockNotifyInfo2, response2.getNotifyInformation().get(0));
    }

    @Test
    @DisplayName("Test NotifyResponse with special characters in filenames")
    void testNotifyResponseWithSpecialCharactersInFilenames() {
        // Create notifications with special characters
        FileNotifyInformation unicodeFile = mock(FileNotifyInformation.class);

```

Again, doing just that declaration, with **FastAPI** you get:

* Editor support (completion, etc.), even for nested models
* Data conversion
* Data validation
* Automatic documentation

## Special types and validation { #special-types-and-validation }

Apart from normal singular types like `str`, `int`, `float`, etc. you can use more complex singular types that inherit from `str`.

 *
 * <p>
 * This class provides methods to:
 * </p>
 * <ul>
 *   <li>Detect the MIME type based on the input stream and filename.</li>
 *   <li>Normalize the filename to handle special characters.</li>
 *   <li>Configure whether to use the filename for MIME type detection.</li>
 *   <li>Configure whether to use the filename for MIME type detection when the stream is octet-stream.</li>
 * </ul>
 *
 * <p>