The error you’re seeing (HTTP Error 307: Temporary Redirect) indicates that the server is trying to redirect your request to another URL temporarily. This is often caused by either a login or session management mechanism on the server that expects certain cookies, headers, or authentication tokens.

1. Redirect and Cookies Handling

• The 307 Temporary Redirect means that the server is sending a redirect to another URL, which is often related to login sessions or post-login redirection. Since you mentioned that you are logged in through the browser, it seems the site expects a valid session to be passed along with the request.

Solution:
- Session Management: Use a session object in urllib or requests to handle cookies and maintain the session between requests.

Here’s an example using requests to handle the session:

```python
import requests
import urllib.parse

# Create a session to maintain the login state
session = requests.Session()

# URL for the form submission
url = ‘https://www.aug.ipp.mpg.de/cgibin/sfread_only/isis?'

shotn = shot_a
# shot_a, shot_z, diag, param are user inputs

while shotn <= shot_z:
values = {
‘shot’: shotn,
‘exp’: ‘AUGD’,
‘diag’: diag,
‘action’: ‘SignalDetails’,
‘signal’: param
}

   data = urllib.parse.urlencode(values).encode('utf-8')

   # Send the POST request through the session
   response = session.post(url, data=data)

   if response.status_code == 200:
       # If the response is successful, handle the data
       respData = response.text
       # Process respData (e.g., save to a file)
   else:
       print(f"Failed to retrieve data for shot {shotn}, Status Code: {response.status_code}")

   shotn += 1

```

In this example:
- Session Handling: requests.Session() automatically manages cookies and headers, keeping your login session active across requests.
- POST Request: Use session.post instead of urllib to send the data. This allows easier handling of form data, cookies, and redirects.
- Response Handling: You can check if the request was successful by looking at response.status_code.

2. Internal Network (Intranet) Issues

Since you mentioned that the website is on an “internal network” rather than the public internet, this could also be a factor:

• Access Restrictions: The website might be accessible only from within the internal network or from IPs that are authenticated through a VPN or other internal infrastructure. If you are outside of the internal network, the request might be blocked or redirected to a login page.

Solution:
- Check Network Access: Ensure you have proper access to the internal network from your script. If you’re using a VPN or a proxy for internal network access, you will need to replicate that in your code (e.g., through requests‘ proxy configuration).

3. Check Headers and Authentication

• Even though you can access the site through the browser, your script might be missing headers (like User-Agent) or other authentication tokens that the website expects.

Solution:
- Mimic the headers from your browser request using the requests library. You can inspect the headers using your browser’s developer tools and replicate them in the script.

Example to add headers:

python headers = { 'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36', # Add any other necessary headers here } response = session.post(url, data=data, headers=headers)

You can find the required headers by inspecting the network traffic in the browser’s developer tools (F12 > Network tab).

4. Redirection Handling

Sometimes, requests or urllib may follow redirects automatically. If you want to handle redirects manually or if the automatic redirection doesn’t work for some reason, you can control it like this:

python response = session.post(url, data=data, allow_redirects=True) # Set allow_redirects=False to handle redirects manually

Summary of Steps:

1. Use requests.Session() to maintain login state and cookies.
2. Handle redirects by ensuring you follow or manage them properly.
3. Mimic browser headers to ensure the server doesn’t block or misinterpret the request.
4. Verify internal network access if the site is on an intranet.

If you still encounter issues after these adjustments, you may need to check how the site is managing sessions and authentication or whether additional network-specific configurations (like VPNs or proxies) are required for access.