VB.NET

Cloudfare DNS over HTTPS

See more Cloudfare Examples

Cloudflare offers a DNS over HTTPS resolver at: https://cloudflare-dns.com/dns-query

This example demonstrates how to do a DNS lookup for a domain using Cloudfare's HTTPS resolver.

VB.NET

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim http As New Chilkat.Http

' Send the following CURL request:   curl -H 'accept: application/dns-json' 'https://cloudflare-dns.com/dns-query?name=chilkat.io&type=A'

http.Accept = "application/dns-json"

Dim url As String = "https://cloudflare-dns.com/dns-query?name=chilkat.io&type=A"

Dim jsonResp As String = http.QuickGetStr(url)
If (http.LastMethodSuccess <> True) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Response Status Code: " & http.LastStatus)

Dim json As New Chilkat.JsonObject
json.Load(jsonResp)
json.EmitCompact = False
Debug.WriteLine(json.Emit())

If (http.LastStatus <> 200) Then
    Debug.WriteLine("Failed.")
    Exit Sub
End If


' Sample output...
' (See the parsing code below..)
' 

' {
'   "Status": 0,
'   "TC": false,
'   "RD": true,
'   "RA": true,
'   "AD": false,
'   "CD": false,
'   "Question": [
'     {
'       "name": "chilkat.io.",
'       "type": 1
'     }
'   ],
'   "Answer": [
'     {
'       "name": "chilkat.io.",
'       "type": 1,
'       "TTL": 900,
'       "data": "52.25.83.238"
'     }
'   ]
' }

' Use this online tool to generate parsing code from sample JSON: 
' Generate Parsing Code from JSON

Dim Status As Integer
Dim TC As Boolean
Dim RD As Boolean
Dim RA As Boolean
Dim AD As Boolean
Dim CD As Boolean
Dim i As Integer
Dim count_i As Integer
Dim name As String
Dim type As Integer
Dim TTL As Integer
Dim data As String
Dim ipAddr As String

Status = json.IntOf("Status")
TC = json.BoolOf("TC")
RD = json.BoolOf("RD")
RA = json.BoolOf("RA")
AD = json.BoolOf("AD")
CD = json.BoolOf("CD")
i = 0
count_i = json.SizeOfArray("Question")
While i < count_i
    json.I = i
    name = json.StringOf("Question[i].name")
    type = json.IntOf("Question[i].type")
    i = i + 1
End While
i = 0
count_i = json.SizeOfArray("Answer")
' The domain name resolves to 1 or more IP addresses..
While i < count_i
    json.I = i
    name = json.StringOf("Answer[i].name")
    type = json.IntOf("Answer[i].type")
    TTL = json.IntOf("Answer[i].TTL")
    ipAddr = json.StringOf("Answer[i].data")

    Debug.WriteLine("IP Address: " & ipAddr)
    i = i + 1
End While