# FastAPI template
It is a simple and handy FastAPI template
for combined frontend and backend as in Flask.  
Includes Jinja, WTForms, MySQL ORM and Docker.


## Features
 - Basic FastAPI app
 - `@app.route`s are defined in separate files
 - Lots of helper functions
 - Jinja2 templates, WTForms
 - MySQL/MariaDB database, SQLAlchemy 2
 - AutoPEP8 formatter, MyPy and Pylint
 - Dockerfile, Docker-Compose


## Usage
1. Create a repository from this template
2. For debugging, change the database connection parameters
in `.env_debug` file correspoding to the configuration
of MariaDB/MySQL server on your PC
3. Edit app [paths](#paths),
[custom error pages](#custom-error-pages)
and [forms](#wtforms)
as explained in the "Structure" section
4. Create your own Jinja templates in the `templates/` directory,
editing `base.html` and inheriting other templates from it is recommended
(see `index,table,admin.html` for examples)
5. Edit or remove CSS and JS files in `static/`
6. Edit `sql/models,schemas,crud.py`
corresponding to your database structure
as explained below ([Structure > Database](#database))
7. Check if `Makefile`, `Dockerfile`, `docker-compose.yml` are correct
8. Run the formatter and linters (`make format`, then `make check`)
9. Build a docker image and [publish](#publishing-app) it

### Makefile
Make commands:
|Command|Description|
|:-----:|:----------|
|`make format`|Format the code using AutoPEP8|
|`make check`|Check the code with linters (MyPy, Pylint)|
|`make dev`|Run the app in development mode|
|`make prod`|Run a production server|
|`make docker`|Build a docker image from `Dockerfile`|
|`make clean`|Clean all cache|


## Structure

### Configuration
#### `.env`s
 - `.env_debug` contains the DB configuration and tokens
 for the development environment, must not be used in production
 - `.env` is a config for the application itself,
 loaded only in docker-compose by default
 - `.env_db` is a config for MySQL/MariaDB server,
 also loaded only in docker-compose for the mariadb container
#### The main config loaded by `app/common.py`:
 - `templates_dir`, `static_dir` contain the paths
 to templates and static files directories correspondingly
 - `settings` (pydantic.BaseSettings):
    - `debug` means the application is running
    in a development environment
    - `session_key`, `csrf_key` are secret keys
    for WTForms CSRF protection;  
    generated with secrets.token_urlsafe
    if are not set in the environment variables
 - `templates` is a Jinja2Templates FastAPI object,
 shouldn't be used manually, see
 Helper Functions -> respond.with_tmpl
 below
#### The database config loaded by `sql/db.py`:
 - `sql_settings` (pydantic.BaseSettings):
    - `db_host`
    - `db_port`
    - `db_user`
    - `db_password`
    - `db_database`
 - `db_url` is the MySQL connection URL
 generated from the sql_settings configuration;  
 just edit the line declaring `db_url` in `db.py`
 if you are going to use other DBMS, e.g. PostgreSQL

### Paths
`app/paths` directory contains all FastAPI paths
separated into multiple files.  
Each file have a class inside with the `add_paths` method.  
This method is called on application startup.

You can
 - add your own paths to the existing files
 - rename or delete a file in `app/paths/`
 (it's *not* recommended to do this with `errors.py`,
 see about [error pages](#custom-error-pages) below)
 - create a new file in this directory
 copying the contents of `pages.py`

> **Note**
> In the paths files, FastAPI's decorators
are called with `@self.app.`, not just `@app.`

In case of deleteing/renaming/creating any paths files,
`app/main.py` also must be modified:
1. Find the comment `# Add your own paths...`
2. Add or remove import statements below
3. Add or remove elements in `paths` list below

### Custom Error Pages
`app/paths/errors.py` automatically adds error handlers
when the application launches.  
By default, 404 and 500 HTTP codes are configured
for the custom pages (`templates/404.html` and `500.html`),
but you can add your own:
1. Open `errors.py`
2. Find the comment `# Add other...`
3. Add (or remove) elements to the list below

### WTForms
TODO

### Database
TODO


## Helper functions

### `respond.py`
Import: `from . import respond`

#### `with_redirect(url=/, code=200, ...)`
Return a redirect to the page specified in `url`.  
By default, code is 302 so method is changed to GET.
To leave the same HTTP method, use 307 status code
or call `with_redirect_307` function.  
`args` and `kwargs` are passed directly
to the Response contructor.

**Args:**
    url (str, optional): Target URL, root by default
    code (int, optional): HTTP response code

**Returns:** FastAPI's RedirectResponse object

#### `with_redirect_302(url=/, ...)`
#### `with_redirect_307(url=/, ...)`
As said before,
 - HTTP 302 Found redirects to a page
 without saving the same method
 as in the current request
 - HTTP 307 Temporary Redirect
 doesn't change the method
 (POST request = POST method after redirect)

#### `with_text(content, code=200, ...)`
Return a plain text to the user.  
`args` and `kwargs` are passed directly
to the Response contructor.

**Args:**
    content (str): Plain text content
    code (int, optional): HTTP response code

**Returns:** FastAPI's PlainTextResponse object

#### `with_template(name, request, code=200, ..., **context)`
#### `with_tmpl(name, request, code=200, ..., **context)`
Render a Jinja2 template and return Response object.  
`response_class` parameter is not needed.  
A small explanation about the `request` function argument:
```python
from fastapi import Request
from . import respond

@app.get('/')
async def main_page(req: Request):  # <--
    return respond.with_tmpl(
        'index.html',
        request=req,  # <--
        ...
    )
```
FastAPI will automatically pass the Request object
to your function if you specify
the correct type hint (`: Request`)

**Args:**
    name (str): Template filename
    request (Request): FastAPI request object
    code (int, optional): HTTP response code
    headers (Optional[Mapping[str, str]], optional):
        Additional headers, passed to the Response constructor
    background (Optional[BackgroundTask], optional):
        Background task, passed to the Response constructor

**Returns:** FastAPI's TemplateResponse object

#### `with_file(path, mime=None, code=200, ...)`
Send the file specified in `path`
automatically guessing its mimetype if `mime` is None.  
`args` and `kwargs` are passed directly
to the Response contructor.

**Args:**
    path (os.PathLike): File path
    mime (Optional[str], optional): File mimetype
    code (int, optional): HTTP response code

**Returns:** FileResponse: FastAPI's FileResponse object

### `forms/__init__.py`
Import: `from . import forms`

#### `async get_form(form, req)`
Almost the same as `form.from_formdata`,
and must be used *instead* of instantiating
form object directly as in Flask.  
See `respond.with_tmpl` for explanation
about the `request` argument.

**Args:**
    form (Type[StarletteForm]): StarletteForm class
    req (Request): Request object

**Returns:** StarletteForm instance

### `sql/db.py`

#### `async get_db()`
FastAPI dependency returning database Session object.  
Code is copied from the official docs.

**Yields:** SQLAlchemy Session object


## Publishing app
First of all, build an image: `make docker`  
Follow [this documentation page](https://docs.docker.com/get-started/04_sharing_app/)
to upload your image to Docker Hub.