Filter Mail by Custom InternetMessageHeaders - microsoft-graph-api

Question

I am able to send mail and add custom internetMessageHeaders. But what I'm attempting to do now is return messages based on filtering to the custom headers I'm adding.
Example:
If I add a custom header to the message for "x-custom-header-productid = x123z" I want to filter and return all messages that have the custom header for x-custom-header-productid that equals x123z. Is this possible?
Thanks!

Answer 1

The header needs to be provisioned in the Mailbox you want to search for it on eg https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/how-to-provision-x-headers-by-using-ews-in-exchange
So in the Graph if you send a Message using that mailbox that would provision it for use in that Mailbox eg
{
"message": {
"subject": "Meet for lunch?",
"body": {
"contentType": "Text",
"content": "The new cafeteria is open."
},
"toRecipients": [
{
"emailAddress": {
"address": "youmailbox#domain.com"
}
}
],
"singleValueExtendedProperties": [
{
"id": "String {00020386-0000-0000-C000-000000000046} Name X-blah-blah",
"value": "Food"
}
]
}
}
You could then search for any messages that arrived (after you provisioned that header)eg which would mean the property would be promoted in the store.
https://graph.microsoft.com/v1.0/me/mailfolders/inbox/messages?$filter=singleValueExtendedProperties/any(ep:ep/id eq 'String {00020386-0000-0000-C000-000000000046} Name X-blah-blah' and ep/value eq 'Food')