# Concurrency and async / await { #concurrency-and-async-await }

Details about the `async def` syntax for *path operation functions* and some background about asynchronous code, concurrency, and parallelism.

## In a hurry? { #in-a-hurry }

<abbr title="too long; didn't read"><strong>TL;DR:</strong></abbr>

If you are using third party libraries that tell you to call them with `await`, like:

```Python
results = await some_library()
```

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.artifact.metadata;

/**
 * Contains metadata about an artifact, and methods to retrieve/store it from an artifact repository.
 */
@Deprecated
public interface ArtifactMetadata extends org.apache.maven.repository.legacy.metadata.ArtifactMetadata {

---
name: Question
about: Use Stack Overflow instead
title: "\U0001F649"
labels: ''
assignees: ''

---

🛑 𝙎𝙏𝙊𝙋

This issue tracker is not the place for questions!

If you want to ask how to do something, or to understand why something isn't working the way you expect it to, use Stack Overflow. https://stackoverflow.com/questions/tagged/okhttp

# Test Client - `TestClient`

You can use the `TestClient` class to test FastAPI applications without creating an actual HTTP and socket connection, just communicating directly with the FastAPI code.

Read more about it in the [FastAPI docs for Testing](https://fastapi.tiangolo.com/tutorial/testing/).

You can import it directly from `fastapi.testclient`:

```python
from fastapi.testclient import TestClient
```

labels: kind/failing-test
body:
  - type: textarea
    id: jobs
    attributes:
      label: Which jobs are failing?
      placeholder: |
        Please only use this template for submitting reports about continuously failing tests or jobs in Kubernetes CI.
    validations:
      required: true

  - type: textarea
    id: tests
    attributes:
      label: Which tests are failing?
    validations:

# o schema   -- The schema name.
# o user     -- The database user name.
# o password -- The database password.
# o propertiesMap -- The properties that depends on the database.
# o variousMap    -- The various settings about JDBC task.
#
# *The line that starts with '#' means comment-out.
#
map:{
    ; driver   = org.h2.Driver
    ; url      = jdbc:h2:file:../src/test/resources/dummydb/dummydb
    ; schema   =  
    ; user     = sa

{* ../../docs_src/body_updates/tutorial001_py310.py hl[28:33] *}

`PUT` is used to receive data that should replace the existing data.

### Warning about replacing { #warning-about-replacing }

That means that if you want to update the item `bar` using `PUT` with a body containing:

```Python
{
    "name": "Barz",
    "price": 3,
    "description": None,
}
```

But first, let's check some small concepts.

## In a hurry? { #in-a-hurry }

If you don't care about any of these terms and you just need to add security with authentication based on username and password *right now*, skip to the next chapters.

## OAuth2 { #oauth2 }

And those two things, `scope` and `receive`, are what is needed to create a new `Request` instance.

To learn more about the `Request` check <a href="https://www.starlette.dev/requests/" class="external-link" target="_blank">Starlette's docs about Requests</a>.

///

The only thing the function returned by `GzipRequest.get_route_handler` does differently is convert the `Request` to a `GzipRequest`.

    """
    An HTTP exception you can raise in your own code to show errors to the client.

    This is for client errors, invalid authentication, invalid data, etc. Not for server
    errors in your code.

    Read more about it in the
    [FastAPI docs for Handling Errors](https://fastapi.tiangolo.com/tutorial/handling-errors/).

    ## Example

    ```python
    from fastapi import FastAPI, HTTPException

    app = FastAPI()