This is normally called a **webhook**.

## Webhooks steps

The process normally is that **you define** in your code what is the message that you will send, the **body of the request**.

You also define in some way at which **moments** your app will send those requests or events.

And **your users** define in some way (for example in a web dashboard somewhere) the **URL** where your app should send those requests.

### Short

It has sensible **defaults** for everything, with optional configurations everywhere. All the parameters can be fine-tuned to do what you need and to define the API you need.

But by default, it all **"just works"**.

### Validation

* Validation for most (or all?) Python **data types**, including:
    * JSON objects (`dict`).

# where fields are strings separated by whitespace.
export TF_VER_MAJOR=$(awk '/#define TF_MAJOR_VERSION/ {print $3}' tensorflow/core/public/version.h)
export TF_VER_MINOR=$(awk '/#define TF_MINOR_VERSION/ {print $3}' tensorflow/core/public/version.h)
export TF_VER_PATCH=$(awk '/#define TF_PATCH_VERSION/ {print $3}' tensorflow/core/public/version.h)

You can import it directly from `fastapi`:

```python
from fastapi import Request
```

!!! tip
    When you want to define dependencies that should be compatible with both HTTP and WebSockets, you can define a parameter that takes an `HTTPConnection` instead of a `Request` or a `WebSocket`.

{{/* Default Prometheus is enabled if its enabled and there are no config overrides set */}} {{ define "default-prometheus" }} {{- and (not .Values.meshConfig.defaultProviders) .Values.telemetry.enabled .Values.telemetry.v2.enabled .Values.telemetry.v2.prometheus.enabled }} {{- end }} {{/* SD has metrics and logging split. Default metrics are enabled if SD is enabled */}} {{ define "default-sd-metrics" }} {{- and (not .Values.meshConfig.defaultProviders) .Values.telemetry.enabled .Values.telemetry.v2.enabled...

{{/* Default Prometheus is enabled if its enabled and there are no config overrides set */}} {{ define "default-prometheus" }} {{- and (not .Values.meshConfig.defaultProviders) .Values.telemetry.enabled .Values.telemetry.v2.enabled .Values.telemetry.v2.prometheus.enabled }} {{- end }} {{/* SD has metrics and logging split. Default metrics are enabled if SD is enabled */}} {{ define "default-sd-metrics" }} {{- and (not .Values.meshConfig.defaultProviders) .Values.telemetry.enabled .Values.telemetry.v2.enabled...

# Lifespan Events

You can define logic (code) that should be executed before the application **starts up**. This means that this code will be executed **once**, **before** the application **starts receiving requests**.

The same way, you can define logic (code) that should be executed when the application is **shutting down**. In this case, this code will be executed **once**, **after** having handled possibly **many requests**.

# `HTTPConnection` class

When you want to define dependencies that should be compatible with both HTTP and WebSockets, you can define a parameter that takes an `HTTPConnection` instead of a `Request` or a `WebSocket`.

You can import it from `fastapi.requests`:

```python
from fastapi.requests import HTTPConnection
```

It is provided directly by Starlette, but you can import it from `fastapi`:

```python
from fastapi import WebSocket
```

!!! tip
    When you want to define dependencies that should be compatible with both HTTP and WebSockets, you can define a parameter that takes an `HTTPConnection` instead of a `Request` or a `WebSocket`.

::: fastapi.WebSocket
    options:
        members:
            - scope
            - app

    with the API key and integrates that into the OpenAPI documentation. It extracts
    the key value sent in the query parameter automatically and provides it as the
    dependency result. But it doesn't define how to send that API key to the client.

    ## Usage

    Create an instance object and use that object as the dependency in `Depends()`.

    The dependency result will be a string containing the key value.