# Exceptions – `HTTPException` und `WebSocketException`

Dies sind die <abbr title="Exception – Ausnahme, Fehler: Python-Objekt, das einen Fehler nebst Metadaten repräsentiert">Exceptions</abbr>, die Sie auslösen können, um dem Client Fehler zu berichten.

# Exceptions - `HTTPException` and `WebSocketException`

These are the exceptions that you can raise to show errors to the client.

When you raise an exception, as would happen with normal Python, the rest of the execution is aborted. This way you can raise these exceptions from anywhere in the code to abort a request and show the error to the client.

You can use:

* `HTTPException`
* `WebSocketException`

    ```

An alternative you could use to catch exceptions (and possibly also raise another `HTTPException`) is to create a [Custom Exception Handler](../handling-errors.md#install-custom-exception-handlers){.internal-link target=_blank}.

## Dependencies with `yield` and `except`

 * includes both natural exceptions such as unreachable servers, as well as synthetic exceptions
 * when responses are of an unexpected type or cannot be decoded.
 *
 * Other exception types cancel the current call:
 *
 *  * For synchronous calls made with [Call.execute], the exception is propagated to the caller.
 *

```

## Install custom exception handlers

You can add custom exception handlers with <a href="https://www.starlette.io/exceptions/" class="external-link" target="_blank">the same exception utilities from Starlette</a>.

Let's say you have a custom exception `UnicornException` that you (or a library you use) might `raise`.

And you want to handle this exception globally with FastAPI.

  @JvmStatic
  val windows: Boolean
    get() = System.getProperty("os.name", "?").startsWith("Windows")

  /**
   * Make assertions about the suppressed exceptions on this. Prefer this over making direct calls
   * so tests pass on GraalVM, where suppressed exceptions are silently discarded.
   *
   * https://github.com/oracle/graal/issues/3008
   */
  @JvmStatic

import org.jetbrains.kotlin.fir.types.*
import org.jetbrains.kotlin.fir.types.impl.ConeClassLikeTypeImpl
import org.jetbrains.kotlin.fir.utils.exceptions.withConeTypeEntry
import org.jetbrains.kotlin.fir.utils.exceptions.withFirEntry
import org.jetbrains.kotlin.fir.utils.exceptions.withFirSymbolEntry
import org.jetbrains.kotlin.fir.visitors.FirVisitorVoid
import org.jetbrains.kotlin.name.ClassId
import org.jetbrains.kotlin.name.FqName

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package gradlebuild.basics.classanalysis

import org.gradle.internal.exceptions.Contextual


@Contextual

import org.jetbrains.kotlin.fir.symbols.resolvedCompilerRequiredAnnotations
import org.jetbrains.kotlin.fir.utils.exceptions.withFirEntry
import org.jetbrains.kotlin.name.*
import org.jetbrains.kotlin.utils.addToStdlib.ifNotEmpty
import org.jetbrains.kotlin.utils.exceptions.checkWithAttachment
import java.lang.annotation.ElementType

import org.jetbrains.kotlin.types.TypeApproximatorConfiguration
import org.jetbrains.kotlin.types.model.CaptureStatus
import org.jetbrains.kotlin.util.bfs
import org.jetbrains.kotlin.utils.exceptions.errorWithAttachment
import org.jetbrains.kotlin.utils.exceptions.withPsiEntry

internal class KtFirTypeProvider(
    override val analysisSession: KtFirAnalysisSession,
    override val token: KtLifetimeToken