79 lines
2.1 KiB
Markdown
79 lines
2.1 KiB
Markdown
# Form Models { #form-models }
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You can use **Pydantic models** to declare **form fields** in FastAPI.
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/// note
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To use forms, first install [`python-multipart`](https://github.com/Kludex/python-multipart).
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Make sure you create a [virtual environment](../virtual-environments.md), activate it, and then install it, for example:
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```console
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$ pip install python-multipart
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```
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///
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/// note
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This is supported since FastAPI version `0.113.0`. 🤓
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///
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## Pydantic Models for Forms { #pydantic-models-for-forms }
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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`:
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{* ../../docs_src/request_form_models/tutorial001_an_py310.py hl[9:11,15] *}
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**FastAPI** will **extract** the data for **each field** from the **form data** in the request and give you the Pydantic model you defined.
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## Check the Docs { #check-the-docs }
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You can verify it in the docs UI at `/docs`:
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<div class="screenshot">
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<img src="/img/tutorial/request-form-models/image01.png">
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</div>
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## Forbid Extra Form Fields { #forbid-extra-form-fields }
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In some special use cases (probably not very common), you might want to **restrict** the form fields to only those declared in the Pydantic model. And **forbid** any **extra** fields.
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/// note
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This is supported since FastAPI version `0.114.0`. 🤓
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///
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You can use Pydantic's model configuration to `forbid` any `extra` fields:
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{* ../../docs_src/request_form_models/tutorial002_an_py310.py hl[12] *}
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If a client tries to send some extra data, they will receive an **error** response.
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For example, if the client tries to send the form fields:
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* `username`: `Rick`
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* `password`: `Portal Gun`
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* `extra`: `Mr. Poopybutthole`
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They will receive an error response telling them that the field `extra` is not allowed:
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```json
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{
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"detail": [
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{
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"type": "extra_forbidden",
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"loc": ["body", "extra"],
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"msg": "Extra inputs are not permitted",
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"input": "Mr. Poopybutthole"
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}
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]
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}
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```
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## Summary { #summary }
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You can use Pydantic models to declare form fields in FastAPI. 😎
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