Macro gets partial response using serverxmlhttp requests - vba

Question

I'm trying to extract street address along with the builder name from a webpage. When I use xmlhttp60 requests I get those fields accordingly. However, when I go for serverxmlhttp60 requests I get partial response most of the times and as a result the script only prints the street adddress. I used json converter to parse builder name out of json content from that site.
Here is the proof of concept:
Sub GrabPropertyInfo()
Const siteLink$ = "https://www.redfin.com/TX/Austin/604-Amesbury-Ln-78752/unit-2/home/171045975"
Dim oPost As Object, oData As Object, Html As HTMLDocument
Dim jsonObject As Object, jsonStr As Object, propertyMainRaw$
Dim itemStr As Variant, sResp As String, oElem As Object
Dim propertyContainer As Object, propertyMain As Object
Set Html = New HTMLDocument
' With CreateObject("MSXML2.XMLHTTP")
' .Open "GET", siteLink, False
' .setRequestHeader "User-Agent", "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.150 Safari/537.36"
' .send
' sResp = .responseText
' Html.body.innerHTML = .responseText
' End With
With CreateObject("MSXML2.ServerXMLHTTP.6.0")
.Open "GET", siteLink, True
.setRequestHeader "User-Agent", "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.150 Safari/537.36"
.send
While .readyState < 4: DoEvents: Wend
sResp = .responseText
Html.body.innerHTML = .responseText
End With
Debug.Print "Street address: " & Html.querySelector("h1.homeAddress > .street-address").innerText
With CreateObject("VBScript.RegExp")
.Global = True
.Pattern = "reactServerState\.InitialContext = (.*);"
.MultiLine = True
Set jsonStr = .Execute(sResp)
End With
itemStr = jsonStr(0).submatches(0)
Set jsonObject = JsonConverter.ParseJson(itemStr)
Set propertyMain = jsonObject("ReactServerAgent.cache")("dataCache")("/stingray/api/home/details/mainHouseInfoPanelInfo")("res")
propertyMainRaw = Replace(propertyMain("text"), "{}&&", "")
On Error Resume Next
Set propertyContainer = JsonConverter.ParseJson(propertyMainRaw)("payload")("mainHouseInfo")("amenitiesInfo")("superGroups")
On Error GoTo 0
If Not propertyContainer Is Nothing Then
For Each oElem In propertyContainer
For Each oPost In oElem("amenityGroups")
If InStr(oPost("groupTitle"), "Building Information") > 0 Then
For Each oData In oPost("amenityEntries")
If InStr(oData("amenityName"), "Builder Name") > 0 Then
Debug.Print "Builder Name: " & oData("amenityValues")(1)
End If
Next oData
End If
Next oPost
Next oElem
End If
End Sub
Using xmlhttp requests, I always get:
Street address: 604 Amesbury Ln #2,
Builder Name: Zach Savage
Using serverxmlhttp requests, I get the following result most of the time:
Street address: 604 Amesbury Ln #2,
How can I get complete response using serverxmlhttp requests?
EDIT:
According to the answer and comments, it is clear that if I scrape browserid from that site using xmlhttp requests and use the value of that browserid as cookie while sending requests using serverxmlhttp, I'll get the desired results. However, The problem is the value of the browserid that I get using xmlhttp requests is sz9u0xmCQKKV9Wu0jRa3Yg whereas I can see this value v-J5D2IUSyqXizI7MG67fQ in page source. How can I get the latter value? This is how I parsed browserid.
Sub FetchBrowserId()
Const siteLink$ = "https://www.redfin.com/TX/Austin/604-Amesbury-Ln-78752/unit-2/home/171045975"
Dim Rxp As Object, browserId As Object, sRes$, cookie$
Set Rxp = CreateObject("VBScript.RegExp")
With CreateObject("MSXML2.XMLHTTP")
.Open "GET", siteLink, False
.setRequestHeader "User-Agent", "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.61 Safari/537.36"
.send
sRes = .responseText
End With
With Rxp
.Global = True
.Pattern = "window.__rfBrowserId=""(.*?)"";"
.MultiLine = True
Set browserId = .Execute(sRes)
End With
cookie = browserId(0).submatches(0)
Debug.Print cookie
End Sub

Answer 1

So the actual question I guess is why there are different responses returned by MSXML2.XMLHTTP and MSXML2.ServerXMLHTTP requests made to the same URL.
MSXML2.XMLHTTP uses WinINet stack and MSXML2.ServerXMLHTTP uses WinHTTP stack. Check WinINet vs. WinHTTP article for more details.
WinINet provide full processing of cookies (BTW IE also rely on it). So the first reason you have different responses is that cookies sent to server may affect flow. It can be easily compared with any service like e. g. Webhook.site. When you make second request with MSXML2.XMLHTTP the webservice logs the cookies which have been accepted from first response.
Also take in account SSL conditions. Make requests to How's My SSL? by MSXML2.XMLHTTP and MSXML2.ServerXMLHTTP, and follow the link in browser (i. e. Chrome) and compare results.