Trouble reusing the same Http after passing it from a sub to a function

Question

I've written a script using xhr to parse the link of the first post from this website and then passed the link and the http to a function to fetch the title from it's inner page. It's important that I pass both the link and the http to the function in order to reuse the same http that I have used in the first place.

My script appears to be working in the right way but I'm not sure I did the whole thing in the right way. The reason for my confusion is that I get the result when I use like getHTTP(ByVal Http, ByVal link) As Variant. I even get the result when I go for getHTTP(ByVal Http, ByVal link) As String or getHTTP(ByVal Http, ByVal link). Moreover, I didn't explicitly define link as String or Http as XMLHTTP60 within function parameters.

I've tried with (working flawlessly):

Function getHTTP(ByVal Http, ByVal link) As Variant
    Dim Html As New HTMLDocument, oTitle$
    
    With Http
        .Open "GET", link, False
        .send
        Html.body.innerHTML = .responseText
        oTitle = Html.querySelector("h1[itemprop='name'] > a").innerText
        getHTTP = oTitle
    End With
End Function

Sub GetInfo()
    Const base$ = "https://stackoverflow.com"
    Const Url$ = "https://stackoverflow.com/questions/tagged/web-scraping"
    Dim Http As New XMLHTTP60, Html As New HTMLDocument
    Dim firstLink$, postTitle$

    With Http
        .Open "GET", Url, False
        .send
        Html.body.innerHTML = .responseText
        firstLink = base & Replace(Html.querySelector(".summary .question-hyperlink").getAttribute("href"), "about:", "")
        postTitle = getHTTP(Http, firstLink)
        MsgBox postTitle
    End With
End Sub

What is the right way to pass http between sub and function in order to reuse the same http?

Answer 1

Something like this might be appropriate:

Sub GetInfo()

    Const base As String = "https://stackoverflow.com"
    Const url As String = "https://stackoverflow.com/questions/tagged/web-scraping"
    Dim Html As HTMLDocument
    Dim firstLink As String, postTitle As String

    firstLink = base & Replace(GetPage(url).querySelector(".summary .question-hyperlink") _
                .getAttribute("href"), "about:", "")
    Debug.Print firstLink

    postTitle = GetPage(firstLink).querySelector("h1[itemprop='name'] > a").innerText
    Debug.Print postTitle

End Sub

Function GetPage(url As String) As HTMLDocument
    Dim Html As HTMLDocument
    Static Http As XMLHTTP60

    If Http Is Nothing Then
        Set Http = New XMLHTTP60
        'log in here
    End If

    With Http
        .Open "GET", url, False
        .send
        If .Status = 200 Then
            Set Html = New HTMLDocument
            Html.body.innerHTML = .responseText
        Else
            Debug.Print .Status
            'warn user
        End If
    End With
    Set GetPage = Html
End Function

Above all assumes the "happy path" so probably would benefit from some exception handling...