Visual Basic for Applications:
Downloading a web page

How to:

To download a web page in VBA, you can make use of the Microsoft XML, v6.0 (MSXML6) library, which enables server HTTP requests. Before diving into the code, ensure you have enabled this reference in your VBA editor by going to Tools -> References and checking Microsoft XML, v6.0.

Here is a simple example of how to download the HTML content of a web page:

Sub DownloadWebPage()
    Dim request As Object
    Dim url As String
    Dim response As String
    
    ' Initialize the XML HTTP request object
    Set request = CreateObject("MSXML2.XMLHTTP")
    
    url = "http://www.example.com"
    
    ' Open a synchronous request
    request.Open "GET", url, False
    
    ' Send the request to the server
    request.send
    
    ' Get the response text
    response = request.responseText
    
    ' Output the response to the immediate window (for debugging purposes)
    Debug.Print response
    
    ' Clean up
    Set request = Nothing
End Sub

Running this subroutine will print the HTML of http://www.example.com to the Immediate Window in the VBA editor. Note that False parameter in the Open method makes the request synchronous, meaning the code will wait until the webpage is downloaded before moving on to the next line.

Deep Dive

The technique shown relies on MSXML, Microsoft’s implementation of the XML HTTP Request standard, often used for AJAX requests in web development. This component has been a part of Microsoft’s technology stack for a long while, making it a robust choice for network requests in VBA.

However, reliance on MSXML and VBA for downloading and parsing web content can be limiting, particularly with modern web applications that heavily use JavaScript for dynamic content rendering. These limitations can make other languages or tools like Python with libraries such as BeautifulSoup or Selenium more suitable for web scraping tasks due to their ability to execute JavaScript and handle complex website interactions.

Despite this, for simple tasks that involve fetching straightforward HTML content or when working within the confines of Office applications, VBA remains a practical tool. Its integration within the Office suite allows for direct manipulation of documents based on web content, offering a unique advantage for specific use cases.