Setting my source to a file path outside of flask static f

ghz 12hours ago ⋅ 7 views

Setting my source to a file path outside of flask static folder

I need to display some images and these image filepaths are outside of flask's static folder stored on on network folders.

<img src="{{ filepath }}"> # /some/external/network/folder/img.jpg

However this is not working and I get a broken image icon, however I can paste the image path into my browser and confirm its accessible. I need this application to be able to accept image sources from anywhere, so I can't update my static folder to the network folder. I also can't load the images to the server because there would be about 20,000+ photos.

Is there a way to get this to work?

Answer

To serve images from a network location that’s outside of Flask's static folder, you have a few options. Since you can't move all the images to Flask's static folder and can't load them all into memory, the best approach is to create a dynamic route in Flask to serve those images directly, based on the file path.

Here’s how you can implement a solution:

1. Use a Flask route to serve the images

Instead of referencing the image path directly in your HTML, you can create a Flask route that dynamically serves the images from the network folder. You can then update the image src in your template to use this route.

Example:

  1. Create a route in Flask to serve images:
import os
from flask import Flask, send_from_directory

app = Flask(__name__)

# Define your network folder path
NETWORK_FOLDER_PATH = r'\\network\folder\path\to\images'  # Adjust to your actual network path

@app.route('/images/<path:filename>')
def serve_image(filename):
    """
    Serve images from a network folder.
    The filename should be passed as part of the URL path.
    """
    # Ensure the file exists
    file_path = os.path.join(NETWORK_FOLDER_PATH, filename)
    if os.path.exists(file_path):
        return send_from_directory(NETWORK_FOLDER_PATH, filename)
    else:
        return 'File not found', 404

if __name__ == '__main__':
    app.run(debug=True)
  • Explanation:
    • send_from_directory is a Flask function that securely sends files from a specified directory.
    • The route /images/<path:filename> takes in the filename as part of the URL, allowing you to serve images from the network location.
    • The path to the network folder (NETWORK_FOLDER_PATH) is used in send_from_directory to fetch the image.
  1. Update your HTML template to reference this route:

Instead of directly linking to the image file (which is outside Flask's static folder), reference the new Flask route that serves the images dynamically.

<img src="{{ url_for('serve_image', filename='img.jpg') }}" alt="Image">
  • Explanation:
    • url_for('serve_image', filename='img.jpg') generates the correct URL for the image based on the Flask route you created.
    • This way, the image will be served via Flask, even though it’s physically located outside of Flask's static folder.

2. Allow access to external directories in production

If you’re deploying this application in a production environment, make sure that the server has proper access to the network folder (i.e., the right permissions and network access).

Additionally, consider setting up a reverse proxy in production (e.g., with Nginx or Apache) to ensure that Flask can handle image requests efficiently without bottlenecking on I/O operations.

3. Performance considerations

Since there are a large number of images (20,000+), you should keep performance in mind:

  • Cache headers: You can add cache headers to serve static content more efficiently and reduce unnecessary requests to the network.
  • Asynchronous loading: If the page has many images, consider using techniques like lazy loading or background fetching to improve the user experience.

Example with caching:

from flask import Response

@app.route('/images/<path:filename>')
def serve_image(filename):
    """
    Serve images with cache headers for better performance.
    """
    file_path = os.path.join(NETWORK_FOLDER_PATH, filename)
    if os.path.exists(file_path):
        response = send_from_directory(NETWORK_FOLDER_PATH, filename)
        response.cache_control.public = True
        response.cache_control.max_age = 86400  # Cache for 24 hours
        return response
    else:
        return 'File not found', 404

Alternative approach: Direct network folder URL (not recommended in all environments)

If the network folder is publicly accessible and can be exposed directly to the browser, you could just use the absolute network URL in the src tag. However, this is often impractical because:

  • It may require configuring your web server or network to allow HTTP access to that folder.
  • There are security and performance concerns when directly exposing file shares over HTTP.

But if it’s possible in your environment, you could use:

<img src="file://<network-path>/img.jpg" alt="Image">

Or serve the files through your web server if you have proper network folder access (e.g., Nginx can serve files from any location).

Conclusion:

The best and most secure solution in your case is to use Flask's dynamic routing (send_from_directory) to serve the images directly, as it allows you to keep the images in a separate network folder and makes sure Flask controls the access and security around serving these files.

#py