Python Flask – How to Serve Static Files

flaskpython

I'm trying to serve a static file using flask. I don't know how to use the url_for function. All my routes generating dynamic content are working fine, I've imported url_for, but when I have this code:

@app.route('/')
def home():
    return url_for('static', filename='hi.html')

Along with my 'hi.html' file (which has some basic html in it) sitting in directory static, what I get when I load the page is literally this:

/static/hi.html

Am I just using url_for incorrectly?

Best Answer

url_for just returns, precisely, the URL for that file. It sounds like you want to redirect to the URL for that file. Instead, you are just sending the text of the URL to the client as a response.

from flask import url_for, redirect

@app.route('/')
def home():
    return redirect(url_for('static', filename='hi.html'))

Related Solutions

Flask Static Files – How to Serve Static Files in Flask

In production, configure the HTTP server (Nginx, Apache, etc.) in front of your application to serve requests to /static from the static folder. A dedicated web server is very good at serving static files efficiently, although you probably won't notice a difference compared to Flask at low volumes.

Flask automatically creates a /static/<path:filename> route that will serve any filename under the static folder next to the Python module that defines your Flask app. Use url_for to link to static files: url_for('static', filename='js/analytics.js')

You can also use send_from_directory to serve files from a directory in your own route. This takes a base directory and a path, and ensures that the path is contained in the directory, which makes it safe to accept user-provided paths. This can be useful in cases where you want to check something before serving the file, such as if the logged in user has permission.

from flask import send_from_directory

@app.route('/reports/<path:path>')
def send_report(path):
    return send_from_directory('reports', path)

Do not use send_file or send_static_file with a user-supplied path. This will expose you to directory traversal attacks. send_from_directory was designed to safely handle user-supplied paths under a known directory, and will raise an error if the path attempts to escape the directory.

If you are generating a file in memory without writing it to the filesystem, you can pass a BytesIO object to send_file to serve it like a file. You'll need to pass other arguments to send_file in this case since it can't infer things like the file name or content type.

Python Flask – How to Serve Static Files Using Nginx

Add this to your nginx configuration

location ^~ /static/  {
    include  /etc/nginx/mime.types;
    root /project_path/;
}

replace /project_path/ with your app's absolute path, you should note that it doesn't include static directory and all the contents inside /project_path/static/ will be serverd in url /static/.

Best Answer

Related Solutions

Flask Static Files – How to Serve Static Files in Flask

Python Flask – How to Serve Static Files Using Nginx

Related Question