Google analytics shows clicks from cached amp pages as direct/none - google-analytics

Question

I implemented AMP pages and they are indexed with no errors and appear in Google search. When a visitor clicks on a link on Google SERP then they appear on Google Analytics (including cached pages) as referenced from organic/google. But when a visitor clicks on a link on that AMP page then the referrer is sometimes expected referral/ampprogect.org and in many cases direct/none.
Of course, amp-analytics is set.
I suspect that direct/none appear when AMP pages served from the main server in response to a click from cached page.
Just in case, AMP were published a few days ago and not all have been discovered by now.
Does it make any sense?
Amp-analytics is implemented in a very basic way
<amp-analytics type="googleanalytics">
<script type="application/json">
{
"vars": {
"account": "UA-XXXXX-Y" //real account id for sure
},
"triggers": {
"trackPageview": {
"on": "visible",
"request": "pageview"
}
}
}
</script>
</amp-analytics>
Update
I set up Google Tag Manager for AMP and changed amp-analitics block with
<amp-analytics config="https://www.googletagmanager.com/amp.json?id=GTM-zzzzzz&gtm.url=SOURCE_URL" data-credentials="include"></amp-analytics>
with the same result.
The click from cached AMP page (that is https://google.com/mydomain-com.cdn...) to non-amp shows referral/ampproject.org and click on non-cached AMP (that is https : //mydomain.com/amp/something.aspx) shows direct/none.

Answer 1

Thanks to this great post I understood what goes wrong and applied the ideas to .NET. The main idea is to catch amp-analytics configuration object (JSON formatted) and replace it with my own (with clientId inside).
First I created HttpHandler
''//.VB
Namespace AmpHandlers
Public Class AmpConfig
Implements IHttpHandler
Private Const unixStart As DateTime = #1/1/1970# ''//start of epoc
Public ReadOnly Property IsReusable As Boolean Implements IHttpHandler.IsReusable
Get
Return False
End Get
End Property
Public Sub ProcessRequest(context As HttpContext) Implements IHttpHandler.ProcessRequest
context.Response.Clear()
''//ecpected request
''// https : //mydomain.com/gtm-amp.json?id=GTM-zzzzzz&gtm.url=SOURCE_URL
If String.IsNullOrEmpty(context.Request.QueryString("id")) OrElse context.Request.QueryString("id") <> "GTM-zzzzzz" Then
''//no answer
context.Response.End()
Return
End If
Dim clientId As String = ""
If context.Request.Cookies("_ga") IsNot Nothing Then
Dim ga As String = context.Request.Cookies("_ga").Value ''//GA1.2.12321354.1507250223
clientId = Regex.Match(ga, "(\d+?\.\d+?$)").Groups(1).Value
Else
Dim rand As New Random()
''//Majic 2147483647 is upper limit of Google's random part of _ga cookie
''//The second part is Unix time, in seconds
clientId = rand.Next(2147483647) & "." & CInt(DateTime.UtcNow.Subtract(unixStart).TotalSeconds)
End If
''//Set cookie and response headers
context.Response.ContentType = "application/json" '; charset=UTF-8
context.Response.SetCookie(New HttpCookie("_ga") With {.Value = "GA1.2." & clientId,
.Path = "/", .Domain = context.Request.Url.Host, .Expires = DateTime.UtcNow.AddYears(2)
})
context.Response.AddHeader("Access-Control-Allow-Origin", "https://mydomain-com.cdn.ampproject.org")
context.Response.AddHeader("Access-Control-Expose-Headers", "AMP-Access-Control-Allow-Source-Origin")
context.Response.AddHeader("AMP-Access-Control-Allow-Source-Origin", "https://" & context.Request.Url.Host)
context.Response.AddHeader("Access-Control-Allow-Source-Origin", "https://" & context.Request.Url.Host)
context.Response.AddHeader("Access-Control-Allow-Credentials", "true")
context.Response.AddHeader("Content-Disposition", "attachment; filename=""GTM-NZPM27T.json""")
context.Response.AddHeader("cache-control", "no-cache, no-store, must-revalidate")
''//https://www.googletagmanager.com/amp.json?id=GTM-zzzzzz&gtm.url=SOURCE_URL response is saved locally and edited
''//possibly it is not the best colution
Dim sr As New IO.StreamReader(context.Server.MapPath("~/amp-gtm.config"))
Dim str As String = sr.ReadToEnd()
str = str.Replace("[[clientId]]", clientId)
context.Response.Write(str)
context.Response.Flush()
context.Response.End()
End Sub
End Class
End Namespace
Next I registered it in web.config.
<handlers>
<add name="amp-gtm" verb="GET" path="gtm-amp.json" type="AmpHandlers.AmpConfig" resourceType="Unspecified"/>
</handlers>
and finally put into amp-analytics tag.
<amp-analytics config="https : //mydomain.com/gtm-amp.json?id=GTM-zzzzzz&gtm.url=SOURCE_URL" data-credentials="include"></amp-analytics>
Now all clicks from cached and non-cached AMP pages show organic/google.