How do you send a HEAD HTTP request in Python 2?

In Python 2, sending a HEAD HTTP request can be achieved through several methods, with the most straightforward approach being the use of the httplib library. Below, I will detail how to utilize this library to send a HEAD request.

Using httplib

httplib is a built-in library in Python 2 for handling HTTP requests. Here are the steps to send a HEAD request using httplib:

1. Import the library: First, import the httplib library.

   python
   import httplib

2. Establish a connection: Create an HTTP connection to the target server.

   python
   conn = httplib.HTTPConnection('www.example.com')

3. Send the HEAD request: Use the request method to send a HEAD request. The HEAD method is one of the pre-defined methods in the HTTP protocol, used to retrieve metadata (such as header information) of a document without fetching the actual content.

   python
   conn.request("HEAD", "/path")

4. Retrieve the response: Obtain the response returned by the server.

   python
   res = conn.getresponse()

5. Read header information: The primary purpose of a HEAD request is to retrieve header information; you can use the getheaders() method to obtain all header details.

   python
   headers = res.getheaders()
   print(headers)

6. Close the connection: Finally, close the connection to release system resources.

   python
   conn.close()

Example Code

Integrating the above steps into a single code snippet:

python
import httplib

def send_head_request():
    # Establish connection to the target server
    conn = httplib.HTTPConnection('www.example.com')
    
    # Send HEAD request
    conn.request("HEAD", "/path")
    
    # Retrieve and process response
    response = conn.getresponse()
    headers = response.getheaders()
    
    # Print header information
    print("Status Code:", response.status)
    print("Headers:")
    for header in headers:
        print(header)
    
    # Close connection
    conn.close()

# Call the function
send_head_request()

In this example, www.example.com should be replaced with the actual domain you wish to query, and /path should be replaced with the actual resource path. This code will print the status code and header information retrieved from the server, which is useful for inspecting metadata of web pages.