# Body - Fields { #body-fields }

The same way you can declare additional validation and metadata in *path operation function* parameters with `Query`, `Path` and `Body`, you can declare validation and metadata inside of Pydantic models using Pydantic's `Field`.

## Import `Field` { #import-field }

First, you have to import it:

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[4] *}


/// warning

vim: set filetype=mustache: */}} {{/* Expand the name of the chart. */}} {{- define "minio.name" -}} {{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" -}} {{- end -}} {{/* Create a default fully qualified app name. We truncate at 63 chars because some Kubernetes name fields are limited to this (by the DNS naming spec). If release name contains chart name it will be used as a full name. */}} {{- define "minio.fullname" -}} {{- if .Values.fullnameOverride -}} {{- .Values.fullnameOverride...

 
 #ifndef _UTMP_H
 # error "Never include <bits/utmp.h> directly; use <utmp.h> instead."
@@ -24,11 +24,13 @@
 #include <time.h>
 
 
-#define	UT_NAMESIZE	8
-#define	UT_LINESIZE	8
-#define	UT_HOSTSIZE	16
+#define UT_LINESIZE	32
+#define UT_NAMESIZE	32
+#define UT_HOSTSIZE	256
 
 
+/* The structure describing an entry in the database of
+   previous logins.  */
 struct lastlog
   {
     time_t ll_time;

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## Declare it as a parameter { #declare-it-as-a-parameter }

To add it to your *path operation*, declare it the same way you declared path and query parameters:

{* ../../docs_src/body/tutorial001_py310.py hl[16] *}

...and declare its type as the model you created, `Item`.

## Results { #results }

      BaseEncoding encoding, String cannotDecode, @Nullable String expectedMessage) {
    // We use this somewhat weird pattern with an enum for each assertion we want to make as a way
    // of dealing with the fact that one of the assertions is @GwtIncompatible but we don't want to
    // have to have duplicate @GwtIncompatible test methods just to make that assertion.

The `root_path` is used to handle these specific cases.

And it's also used internally when mounting sub-applications.

Having a proxy with a stripped path prefix, in this case, means that you could declare a path at `/app` in your code, but then, you add a layer on top (the proxy) that would put your **FastAPI** application under a path like `/api/v1`.

In this case, the original path `/app` would actually be served at `/api/v1/app`.

///

/// note

This is supported since FastAPI version `0.113.0`. 🤓

///

## Pydantic Models for Forms { #pydantic-models-for-forms }

You just need to declare a **Pydantic model** with the fields you want to receive as **form fields**, and then declare the parameter as `Form`:

{* ../../docs_src/request_form_models/tutorial001_an_py39.py hl[9:11,15] *}

      val length = logMessage.length
      while (i < length) {
        var newline = logMessage.indexOf('\n', i)
        newline = if (newline != -1) newline else length
        do {
          val end = minOf(newline, i + MAX_LOG_LENGTH)
          Log.println(logLevel, tag, logMessage.substring(i, end))
          i = end
        } while (i < newline)
        i++
      }
    }
  }

vim: set filetype=mustache: */}} {{/* Expand the name of the chart. */}} {{- define "minio.name" -}} {{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" -}} {{- end -}} {{/* Create a default fully qualified app name. We truncate at 63 chars because some Kubernetes name fields are limited to this (by the DNS naming spec). If release name contains chart name it will be used as a full name. */}} {{- define "minio.fullname" -}} {{- if .Values.fullnameOverride -}} {{- .Values.fullnameOverride...

vim: set filetype=mustache: */}} {{/* Expand the name of the chart. */}} {{- define "minio.name" -}} {{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" -}} {{- end -}} {{/* Create a default fully qualified app name. We truncate at 63 chars because some Kubernetes name fields are limited to this (by the DNS naming spec). If release name contains chart name it will be used as a full name. */}} {{- define "minio.fullname" -}} {{- if .Values.fullnameOverride -}} {{- .Values.fullnameOverride...