`from flask import Flask, render_template, request, abort
import requests
import os
from werkzeug.utils import secure_filename

app = Flask(name)

Create necessary directories

os.makedirs('static/images', exist_ok=True)

@app.route('/')
def index():
return render_template('index.html')

@app.route('/fetch/path:image_url')
def fetch_image(image_url):
try:
# Fetch image from provided URL
response = requests.get(image_url, stream=True)

if response.status_code != 200:
        return abort(404, "Could not fetch image from URL")

    # Generate a secure filename for the image
    filename = secure_filename(image_url.split('/')[-1])
    if not filename.endswith('.png'):
        filename = filename.split('.')[0] + '.png'

    # Save the image
    img_path = os.path.join('static/images', filename)
    with open(img_path, 'wb') as f:
        for chunk in response.iter_content(1024):
            f.write(chunk)

    # Store image info in a variable that will be passed to template
    img1 = {
        'filename': filename,
        'path': f'images/{filename}',
        'source_url': image_url
    }

    return render_template('image.html', img1=img1)

except Exception as e:
    return abort(500, f"Error processing image: {str(e)}")

if name == 'main':
app.run(debug=True)`

Here’s a clean and clear explanation of the Flask code you’ve shared, with a focus on what each part does and how the image fetching works:

✅ Purpose of This App:

This Flask app takes an image URL as input, fetches the image from the internet, saves it locally in a static/images folder, and displays it on a webpage.

🔍 Code Breakdown:

1. Imports

from flask import Flask, render_template, request, abort
import requests
import os
from werkzeug.utils import secure_filename

Flask – creates the web application.
render_template – renders HTML templates.
request – handles incoming data (not directly used here, but useful if you plan to extend it).
abort – returns error codes like 404 or 500.
requests – used to fetch the image from a URL.
os – helps in creating folders and handling file paths.
secure_filename – safely formats the filename to avoid path traversal and other issues.

2. App Setup and Directory Creation

app = Flask(__name__)
os.makedirs('static/images', exist_ok=True)

Flask(__name__) – starts the Flask app.
os.makedirs(...) – creates the folder static/images if it doesn’t already exist.

3. Homepage Route

@app.route('/')
def index():
    return render_template('index.html')

Loads index.html when you open the root URL /.

4. Image Fetching Route

@app.route('/fetch/')
def fetch_image(image_url):

This route is triggered when the user goes to /fetch/.
allows slashes in the image URL.

5. Fetch and Save the Image

response = requests.get(image_url, stream=True)

Sends a GET request to fetch the image content.

if response.status_code != 200:
    return abort(404, "Could not fetch image from URL")

If the image is not available (status ≠ 200), return a 404 error.

6. Create a Safe Filename

filename = secure_filename(image_url.split('/')[-1])

Extracts the last part of the URL (likely the filename) and secures it.

if not filename.endswith('.png'):
    filename = filename.split('.')[0] + '.png'

Ensures the file ends with .png for uniformity.

7. Save the Image Locally

img_path = os.path.join('static/images', filename)
with open(img_path, 'wb') as f:
    for chunk in response.iter_content(1024):
        f.write(chunk)

Saves the image in chunks (1KB at a time) to static/images.

8. Prepare Image Info for Display

img1 = {
    'filename': filename,
    'path': f'images/{filename}',
    'source_url': image_url
}

A dictionary storing info about the saved image: filename, relative path, and original source URL.

9. Render the Image Page

return render_template('image.html', img1=img1)

Passes the image info to image.html to display it.

10. Error Handling

except Exception as e:
    return abort(500, f"Error processing image: {str(e)}")

Handles unexpected errors (network issues, disk problems, etc.) and shows a 500 error.

11. Start the Flask App

if __name__ == '__main__':
    app.run(debug=True)

Starts the app in debug mode for easier development and error tracking.

🖼️ Folder Structure Assumed:

project_folder/
│
├── app.py
├── templates/
│   ├── index.html
│   └── image.html
└── static/
    └── images/

✅ TL;DR:

What it does: Takes an image URL, fetches it, saves it as .png, and displays it.
Key features: Safe filename handling, local storage, error handling, and rendering via templates.
Useful for: Image preview tools, downloaders, or web-based image processors.

Would you like me to give sample index.html and image.html code too, to complete this app?

for soniya - shreya