FastAPI-VO 0.1.4
Utilities to simplify FastAPI view objects
License: MIT
Requires Python: >=3.6
Keywords: fastapi,view objects,model

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<p align="center">
    <em>FastAPI-VO, view objects for FastAPI designed for simplicity.</em>
</p>

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---

**Documentation**: <a href="https://fastapi-vo.r3ck.com.br" target="_blank">https://fastapi-vo.r3ck.com.br</a>

**Source Code**: <a href="https://github.com/rennancockles/fastapi-vo" target="_blank">https://github.com/rennancockles/fastapi-vo</a>

---

FastAPI-VO is a lightweight library for creating simple <a href="https://pydantic-docs.helpmanual.io/" class="external-link" target="_blank">FastAPI</a> view objects just by `picking` or `omitting` parts of a model. It is designed to be simple, intuitive and easy to use.

It is so simple that doesn't need much explanation. Just check some examples below.


## Requirements

A recent and currently supported version of Python (right now, <a href="https://www.python.org/downloads/" class="external-link" target="_blank">Python supports versions 3.6 and above</a>).

**FastAPI-VO** only requires **FastAPI**, but it will be automatically installed when you install FastAPI-VO.

## Installation

<div class="termy">

```console
$ pip install fastapi-vo
---> 100%
Successfully installed fastapi-vo
```

</div>

## Example

For an introduction to FastAPI, see the <a href="https://fastapi.tiangolo.com/" class="external-link" target="_blank">FastAPI documentation</a>.

Here's a quick example. âœ¨

<details>
<summary>ðŸ‘€ Full code preview</summary>


```Python
from typing import List
from fastapi import FastAPI
from pydantic import BaseModel

from fastapi_vo import Omit, Pick


class User(BaseModel):
    username: str
    password: str
    is_active: bool = True
    is_admin: bool = False


Auth = Pick(User, ["username", "password"], classname="Auth")
NoPassword = Omit(User, "password", classname="NoPasswordUser")

app = FastAPI()
johndoe = User(
    username="johndoe",
    password="secret",
    is_admin=False,
    is_active=True,
)
janedoe = User(
    username="janedoe",
    password="janesecret",
    is_admin=True,
    is_active=True,
)


@app.get("/users/", response_model=List[NoPassword])
async def list_users():
    return [johndoe, janedoe]


@app.get("/users/john/", response_model=NoPassword)
async def get_user():
    return johndoe


@app.get("/login/", response_model=NoPassword)
async def login(user: Auth):
    # some authentication logic in here
    return user
```

</details>


### Create a Model

Let's create a model called `user` with:

* `username`
* `password`
* `is_active`
* `is_admin`


```Python hl_lines="1 4-8"
from pydantic import BaseModel


class User(BaseModel):
    username: str
    password: str
    is_active: bool = True
    is_admin: bool = False


johndoe = User(
    username="johndoe",
    password="secret",
    is_admin=False,
    is_active=True,
)

janedoe = User(
    username="janedoe",
    password="janeSecret",
    is_admin=True,
    is_active=True,
)
```

Now we create 2 instances of the **User** model:


```Python hl_lines="11-16 18-23"
from pydantic import BaseModel


class User(BaseModel):
    username: str
    password: str
    is_active: bool = True
    is_admin: bool = False


johndoe = User(
    username="johndoe",
    password="secret",
    is_admin=False,
    is_active=True,
)

janedoe = User(
    username="janedoe",
    password="janeSecret",
    is_admin=True,
    is_active=True,
)
```

### Create a Route

Now we are going to create a FastAPI app with a route to get the user data.


```Python hl_lines="1 26 29-31"
from fastapi import FastAPI
from pydantic import BaseModel


class User(BaseModel):
    username: str
    password: str
    is_active: bool = True
    is_admin: bool = False


johndoe = User(
    username="johndoe",
    password="secret",
    is_admin=False,
    is_active=True,
)

janedoe = User(
    username="janedoe",
    password="janeSecret",
    is_admin=True,
    is_active=True,
)

app = FastAPI()


@app.get("/user/john", response_model=User)
async def get_john():
    return johndoe
```

This way, FastAPI will return all the user data, including the **password**, and it is not a good thing to do.


### Omitting a field

Now let's use the **Omit** function to return everything from the user **but** the password.


```Python hl_lines="4 31"
from fastapi import FastAPI
from pydantic import BaseModel

from fastapi_vo import Omit


class User(BaseModel):
    username: str
    password: str
    is_active: bool = True
    is_admin: bool = False


johndoe = User(
    username="johndoe",
    password="secret",
    is_admin=False,
    is_active=True,
)

janedoe = User(
    username="janedoe",
    password="janeSecret",
    is_admin=True,
    is_active=True,
)

app = FastAPI()


@app.get("/user/john", response_model=Omit(User, "password"))
async def get_john():
    return johndoe
```

### Multiple variations of the same model

If you want to use multiple variations of the same class, you have to give it a new `classname` to avoid conflicts. Another approach is to assign it to a **variable** for reuse.


```Python hl_lines="1 15 35-37 40"
from typing import List
from fastapi import FastAPI
from pydantic import BaseModel

from fastapi_vo import Omit


class User(BaseModel):
    username: str
    password: str
    is_active: bool = True
    is_admin: bool = False


NoPassword = Omit(User, "password", classname="NoPasswordUser")


johndoe = User(
    username="johndoe",
    password="secret",
    is_admin=False,
    is_active=True,
)

janedoe = User(
    username="janedoe",
    password="janeSecret",
    is_admin=True,
    is_active=True,
)

app = FastAPI()


@app.get("/users", response_model=List[NoPassword])
async def list_users():
    return [johndoe, janedoe]


@app.get("/user/john", response_model=NoPassword)
async def get_john():
    return johndoe
```


### Picking a field

Now let's create a login route with another variation of the user model by picking some fields.


```Python hl_lines="5 16 46-50"
from typing import List
from fastapi import FastAPI
from pydantic import BaseModel

from fastapi_vo import Omit, Pick


class User(BaseModel):
    username: str
    password: str
    is_active: bool = True
    is_admin: bool = False


NoPassword = Omit(User, "password", classname="NoPasswordUser")
Auth = Pick(User, ["username", "password"], classname="Auth")


johndoe = User(
    username="johndoe",
    password="secret",
    is_admin=False,
    is_active=True,
)

janedoe = User(
    username="janedoe",
    password="janeSecret",
    is_admin=True,
    is_active=True,
)

app = FastAPI()


@app.get("/users", response_model=List[NoPassword])
async def list_users():
    return [johndoe, janedoe]


@app.get("/user/john", response_model=NoPassword)
async def get_john():
    return johndoe


@app.get("/login", response_model=NoPassword)
async def login(user: Auth):
    # some authentication logic in here
    return user
```


## License

This project is licensed under the terms of the MIT license.