excel vba download text file from the internet that update every 5 minutes

Question

I wanted to download a file from this link: https://www.hko.gov.hk/tide/marine/data/ALL.txt

This file updates itself every 5 minutes. So I went on and create an excel VB

Answer 1

There may be caching. Try the following where a requestHeader is added to try and mitigate for potential caching. The other common alternative, adding a random number to the end of the URL doesn't seem to work for this site.

Option Explicit

Public Sub test()
    Dim i As Long
    For i = 1 To 3
        DownloadFile "https://www.hko.gov.hk/tide/marine/data/ALL.txt"
        Debug.Print Now
        Application.Wait Now + TimeSerial(0, 5, 0)
    Next
End Sub

Public Sub DownloadFile(ByVal link As String)
    Dim WinHttpReq As Object, oStream  As Object
    Set WinHttpReq = CreateObject("Microsoft.XMLHTTP")
    With WinHttpReq
        .Open "GET", link, False
        .setRequestHeader "If-Modified-Since", "Sat, 1 Jan 2000 00:00:00 GMT"
        .send

        Debug.Print StrConv(.responsebody, vbUnicode)

        If WinHttpReq.Status = 200 Then
            Set oStream = CreateObject("ADODB.Stream")
            oStream.Open
            oStream.Type = 1
            oStream.Write .responsebody
            oStream.SaveToFile ThisWorkbook.Path & "\raw\" & "temp.csv", 2 ' 1 = no overwrite, 2 = overwrite
            oStream.Close
        End If

    End With

End Sub