# 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()`

    fi
  done
  echo "$basedir"
)
}

# concatenates all lines of a file and replaces variables
# Uses Java-based parser to handle all special characters correctly
# This avoids shell parsing issues with pipes, quotes, @, and other special characters
# and ensures POSIX compliance (no xargs -0, awk, or complex sed needed)
# Set MAVEN_DEBUG_SCRIPT=1 to enable debug logging
concat_lines() {
  if [ -f "$1" ]; then

# Request Parameters

Here's the reference information for the request parameters.

These are the special functions that you can put in *path operation function* parameters or dependency functions with `Annotated` to get data from the request.

It includes:

* `Query()`
* `Path()`
* `Body()`
* `Cookie()`
* `Header()`
* `Form()`
* `File()`

You can import them all directly from `fastapi`:

```python

LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

  constructor(name: ByteString, value: String) : this(name, value.encodeUtf8())

  override fun toString(): String = "${name.utf8()}: ${value.utf8()}"

  companion object {
    // Special header names defined in HTTP/2 spec.
    @JvmField val PSEUDO_PREFIX: ByteString = ":".encodeUtf8()

    const val RESPONSE_STATUS_UTF8 = ":status"
    const val TARGET_METHOD_UTF8 = ":method"

    // 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

   * available for all platforms and configurations. If that implementation is unavailable, this
   * method falls back to {@code getStackTrace}. Callers that require the special implementation can
   * check its availability with {@link #lazyStackTraceIsLazy()}.
   *
   * <p>The expected (but not guaranteed) performance of the special implementation differs from

# 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

  <modelVersion>4.0.0</modelVersion>

  <groupId>inheritance</groupId>
  <artifactId>parent</artifactId>
  <version>11-SNAPSHOT</version>

  <name>Model urls inheritance test parent, with special merge test for mergeSite_ChildSiteUrlInheritAppendPath</name>

  <scm child.scm.connection.inherit.append.path="false"
       child.scm.developerConnection.inherit.append.path="false"

            {
              "options": {
                "match": "null",
                "result": {
                  "text": "N/A"
                }
              },
              "type": "special"
            }
          ],
          "thresholds": {
            "mode": "percentage",
            "steps": [
              {
                "color": "green",
                "value": null
              }