**FastAPI**'s `UploadFile` inherits directly from **Starlette**'s `UploadFile`, but adds some necessary parts to make it compatible with **Pydantic** and the other parts of FastAPI.

///

## What is "Form Data" { #what-is-form-data }

The way HTML forms (`<form></form>`) sends the data to the server normally uses a "special" encoding for that data, it's different from JSON.

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] *}

**FastAPI** will **extract** the data for **each field** from the **form data** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

This is because we also have another variable named `router` in the submodule `users`.

If we had imported one after the other, like:

```Python
from .routers.items import router
from .routers.users import router
```

the `router` from `users` would overwrite the one from `items` and we wouldn't be able to use them at the same time.

So, to be able to use both of them in the same file, we import the submodules directly:

}

func buildServerCtxt(ctx *cli.Context, ctxt *serverCtxt) (err error) {
	// Get "json" flag from command line argument and
	ctxt.JSON = ctx.IsSet("json") || ctx.GlobalIsSet("json")
	// Get quiet flag from command line argument.
	ctxt.Quiet = ctx.IsSet("quiet") || ctx.GlobalIsSet("quiet")
	// Get anonymous flag from command line argument.
	ctxt.Anonymous = ctx.IsSet("anonymous") || ctx.GlobalIsSet("anonymous")

/// tip

To declare form bodies, you need to use `Form` explicitly, because without it the parameters would be interpreted as query parameters or body (JSON) parameters.

///

## About "Form Fields" { #about-form-fields }

The way HTML forms (`<form></form>`) sends the data to the server normally uses a "special" encoding for that data, it's different from JSON.

**FastAPI** will make sure to read that data from the right place instead of JSON.

            to.ansiHash = from.ansiHash != null ? Arrays.copyOf(from.ansiHash, from.ansiHash.length) : null;
            to.unicodeHash = from.unicodeHash != null ? Arrays.copyOf(from.unicodeHash, from.unicodeHash.length) : null;
        } else {
            NtlmPasswordAuthenticator.cloneInternal(to, from);
        }
    }

    /**
     * Compares two {@code NtlmPasswordAuthentication} objects for

        }
        // Can't map from a raw class to anything other than itself or a wildcard.
        // You can't say "assuming String is Integer".
        // And we don't support "assuming String is T"; user has to say "assuming T is String".
        throw new IllegalArgumentException("No type mapping from " + fromClass + " to " + to);
      }
    }.visit(from);
  }

  /**

        long data4 = bb2.getLong();

        // Construct UUID from components - Java UUID expects big-endian representation
        long mostSig = ((long) data1 << 32) | ((long) (data2 & 0xFFFF) << 16) | (data3 & 0xFFFF);
        long leastSig = data4;

        this.guid = new UUID(mostSig, leastSig);
    }

    /**
     * Create a handle GUID from existing UUID
     * @param uuid the UUID to wrap
     */

///

### What is "Mounting" { #what-is-mounting }

"Mounting" means adding a complete "independent" application in a specific path, that then takes care of handling all the sub-paths.

With this, we get tooling support, from editors and mypy as this code is correct in terms of types, but we also get the data filtering from FastAPI.

How does this work? Let's check that out. 🤓

### Type Annotations and Tooling { #type-annotations-and-tooling }

First let's see how editors, mypy and other tools would see this.