Library that works with Flask & SqlAlchemy to store files on your server & in your database
Read the docs: Documentation
Installation
Please install the latest stable release:
pip install flask-file-upload
General Flask config options
(Important: The below configuration variables need to be set before initiating FileUpload)
# This is the directory that flask-file-upload saves files to. Make sure the UPLOAD_FOLDER is the same as Flasks's static_folder or a child. For example:
app.config["UPLOAD_FOLDER"] = join(dirname(realpath(__file__)), "static/uploads")
# Other FLASK config varaibles ...
app.config["ALLOWED_EXTENSIONS"] = ["jpg", "png", "mov", "mp4", "mpg"]
app.config["MAX_CONTENT_LENGTH"] = 1000 * 1024 * 1024 # 1000mb
app.config["SQLALCHEMY_DATABASE_URI"] = "postgresql://localhost:5432/blog_db"
Setup
We can either pass the instance to FileUpload(app) or to the init_app(app) method:
from flask_jwt_router import JwtRoutes
app = Flask(__name__, static_folder="static") # IMPORTANT: This is your root directory for serving ALL static content!
db = SQLAlchemy()
file_upload = FileUpload()
# An example using the Flask factory pattern
def create_app():
db.init_app(app)
# Pass the Flask app instance as the 1st arg &
# the SQLAlchemy object as the 2nd arg to file_upload.init_app.
file_upload.init_app(app, db)
# If you require importing your SQLAlchemy models then make sure you import
# your models after calling `file_upload.init_app(app, db)` or `FileUpload(app, db)`.
from .model import *
# Or we can pass the Flask app instance directly & the Flask-SQLAlchemy instance:
db = SQLAlchemy(app)
# Pass the Flask app instance as the 1st arg &
# the SQLAlchemy object as the 2nd arg to FileUpload
file_upload = FileUpload(app, db)
app: Flask = None
Decorate your SqlAlchemy models
Flask-File-Upload (FFU) setup requires each SqlAlchemy model that wants to use FFU library to be decorated with @file_upload.Model .This will enable FFU to update your database with the extra columns required to store files in your database. Declare your attributes as normal but assign a value of file_upload.Column. This is easy if you are using Flask-SqlAlchemy:
from flask_sqlalchemy import SqlAlchemy
db = SqlAlchemy()
Full example:
from my_app import file_upload
@file_upload.Model
class blogModel(db.Model):
__tablename__ = "blogs"
id = db.Column(db.Integer, primary_key=True)
# Use flask-file-upload's `file_upload.Column()` to associate a file with a SQLAlchemy Model:
my_placeholder = file_upload.Column()
my_video = file_upload.Column()
define files to be uploaded:
# A common scenario could be a video with placeholder image.
# So first lets grab the files from Flask's request object:
my_video = request.files["my_video"]
placeholder_img = request.files["placeholder_img"]
Save files
Now we have the files assigned to variables, we can start using the m with flask-file-upload:
file_upload.save_files(blog_post, files={
"my_video": my_video,
"placeholder_img": placeholder_img,
})
If you followed the setup above you will see the following structure saved to your app:
Update files
blog_post = file_upload.update_files(blog_post, files={
"my_video": new_my_video,
"placeholder_img": new_placeholder_img,
})
Delete files
Deleting files from the db & server can be non trivial, especially to keep both in sync. The file_upload.delete_files method can be called with a kwarg of clean_up & then depending of the string value passed it will provide 2 types of clean up functionality:
fileswill clean up files on the server but not update the modelmodelwill update the model but not attempt to remove the files from the server. See delete_files Docs for more details
# Example using a SqlAlchemy model with an appended
# method that fetches a single `blog`
blogModel = BlogModel()
blog_results = blogModel.get_one()
# We pass the blog & files
blog = file_upload.delete_files(blog_result, files=["my_video"])
# If parent kwarg is set to True then the root primary directory & all its contents will be removed.
# The model will also get cleaned up by default unless set to `False`.
blog_result = file_upload.delete_files(blog_result, parent=True, files=["my_video"])
# If the kwarg `commit` is not set or set to True then the updates are persisted.
# to the session. And therefore the session has been commited.
blog = file_upload.delete_files(blog_result, files=["my_video"])
# Example of cleaning up files but not updating the model:
blog = file_upload.delete_files(blog_result, files=["my_video"], clean_up="files")
Stream a file
file_upload.stream_file(blog_post, filename="my_video")
File Url paths
file_upload.get_file_url(blog_post, filename="placeholder_img")
Example for getting file urls from many objects:
# If blogs_model are many blogs:
for blog in blog_models:
blog_image_url = file_upload.get_file_url(blog, filename="blog_image")
setattr(blog, "blog_image", blog_image_url)
Set file paths to multiple objects – Available in 0.1.0-rc.6 & v0.1.0
The majority of requests will require many entities to be returned & these entities may have SQLAlchemy backrefs with relationships that may also contain Flask-File-Upload (FFU) modified SQLAlchemy models. To make this trivial, this method will set the appropriate filename urls to your SQLAlchemy model objects (if the transaction hasn’t completed then add_file_urls_to_models will complete the transaction by default).
The first argument required by this method is models – the SQLAlchemy model(s).
Then pass in the required kwarg filenames which references the parent’s FFU Model values – this is the file_upload.Model decorated SQLALchemy model
file_upload.Column()method.
Important! Also take note that each attribute set by this method postfixes a _url tag. e.g blog_image becomes blog_image_url
Example for many SQLAlchemy entity objects (or rows in your table)::
@file_upload.Model
class BlogModel(db.Model):
blog_image = file_upload.Column()
Now we can use the file_upload.add_file_urls_to_models to add file urls to each SQLAlchemy object. For example::
blogs = add_file_urls_to_models(blogs, filenames="blog_image")
# Notice that we can get the file path `blog_image` + `_url`
assert blogs[0].blog_image_url == "path/to/blogs/1/blog_image_url.png"
To set filename attributes to a a single or multiple SQLAlchemy parent models with backrefs to multiple child SQLAlchemy models, we can assign to the optional backref kwarg the name of the backref model & a list of the file attributes we set with the FFU Model decorated SQLAlchemy model.
To use backrefs we need to declare a kwarg of backref & pass 2 keys: – name: The name of the backref relation – filenames: The FFU attribute values assigned to the backref model
For example::
# Parent model
@file_upload.Model
class BlogModel(db.Model):
# The backref:
blog_news = db.relationship("BlogNewsModel", backref="blogs")
blog_image = file_upload.Column()
blog_video = file_upload.Column()
# Model that has a foreign key back up to `BlogModel
@file_upload.Model
class BlogNewsModel(db.Model):
# The foreign key assigned to this model:
blog_id = db.Column(db.Integer, db.ForeignKey("blogs.blog_id"))
news_image = file_upload.Column()
news_video = file_upload.Column()
The kwarg backref keys represent the backref model or entity (in the above example this would be the BlogNewsModel which we have named blog_news. Example::
blogs = add_file_urls_to_models(blogs, filenames=["blog_image, blog_video"],
backref={
"name": "blog_news",`
"filenames": ["news_image", "news_video],
})
WARNING: You must not set the relationship kwarg: lazy="dynamic"! If backref is set to “dynamic” then back-referenced entity’s filenames will not get set. Example::
# This will work
blog_news = db.relationship("BlogNewsModel", backref="blog")
# this will NOT set filenames on your model class
blog_news = db.relationship("BlogNewsModel", backref="blog", lazy="dynamic")
Running Flask-Migration After including Flask-File-Upload in your project
The arguments below will also run if you’re using vanilla Alembic.
export FLASK_APP=flask_app.py # Path to your Flask app
# with pip
flask db stamp head
flask db migrate
flask db upgrade
# with pipenv
pipenv run flask db stamp head
pipenv run flask db migrate
pipenv run flask db upgrade
