### Bigger Errors - Crashes { #bigger-errors-crashes }

Nevertheless, there might be cases where we write some code that **crashes the entire application** making Uvicorn and Python crash. 💥

And still, you would probably not want the application to stay dead because there was an error in one place, you probably want it to **continue running** at least for the *path operations* that are not broken.

their faces.  There was a sound of many footsteps, and Alice
looked round, eager to see the Queen.

  First came ten soldiers carrying clubs; these were all shaped
like the three gardeners, oblong and flat, with their hands and
feet at the corners:  next the ten courtiers; these were
ornamented all over with diamonds, and walked two and two, as the
soldiers did.  After these came the royal children; there were

There is some assistance in the IDE for this plus a lot of validation that is applied at build time and on CI, but it is useful to keep these constraints in mind as well.

See [Gradle runtimes](runtimes.md) for a list of these runtimes and more details.

### Build execution model

That means that, clients using your API don't have to check if the value exists or not, they can **assume the field will always be there**, but just that in some cases it will have the default value of `None`.

The way to describe this in OpenAPI, is to mark that field as **required**, because it will always be there.

Because of that, the JSON Schema for a model can be different depending on if it's used for **input or output**:

If there is no discussion for that language, you can start by requesting the new language. For that, you can follow these steps:

* Create a new discussion following the template.
* Get a few native speakers to comment on the discussion and commit to help review translations for that language.

In these cases, you would normally return an **HTTP status code** in the range of **400** (from 400 to 499).

This is similar to the 200 HTTP status codes (from 200 to 299). Those "200" status codes mean that somehow there was a "success" in the request.

The status codes in the 400 range mean that there was an error from the client.

Remember all those **"404 Not Found"** errors (and jokes)?

## Use `HTTPException` { #use-httpexception }

# OpenAPI Webhooks { #openapi-webhooks }

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

            // Optimization to skip streaming, distincting, and collecting to a new list when there is zero or one
            // project, aka there can't be duplicates.
            return filtered;
        }

        // Distinct the projects to avoid duplicates.  Duplicates are possible in multi-module projects.
        //
        // Given a scenario where there is an aggregate POM with modules A, B, C, D, and E and project E depends on

    * HTTP Digest, etc.
* `oauth2`: all the OAuth2 ways to handle security (called "flows").
    * Several of these flows are appropriate for building an OAuth 2.0 authentication provider (like Google, Facebook, X (Twitter), GitHub, etc):
        * `implicit`
        * `clientCredentials`
        * `authorizationCode`
    * But there is one specific "flow" that can be perfectly used for handling authentication in the same application directly:

	// ErrDuplicatedKey occurs when there is a unique key constraint violation
	ErrDuplicatedKey = errors.New("duplicated key not allowed")
	// ErrForeignKeyViolated occurs when there is a foreign key constraint violation
	ErrForeignKeyViolated = errors.New("violates foreign key constraint")
	// ErrCheckConstraintViolated occurs when there is a check constraint violation