Gmail API In-Reply-To not working(Google not handling on one side)

Question

Problem: When Reply to email is sent via api then in receiver side it is showing as thread that contains two email messages(good on receivers side

Answer 1

Noticed this in my production app today as well. The change log did not give a clue as to what happened, but I found the problem in the new documentation for managing threads:

1. The requested threadId must be specified on the Message or Draft.Message you supply with your request.
2. The References and In-Reply-To headers must be set in compliance with the RFC 2822 standard.
3. The Subject headers must match.

In other words, the threadId needs to be supplied. I don't know if this is a bug or not, since it is not documented in the sending message-documentation that was updated on the same day.

I want to respond to the latest message in my inbox. Let's get the relevant information:

Request 1:

maxResults = 1
fields = messages/id

GET https://www.googleapis.com/gmail/v1/users/me/messages?maxResults=1&fields=messages%2Fid

Response 1:

{
 "messages": [
  {
   "id": "15071b210a1ac883",
   "threadId": "15071a4886871a10"
  }
 ]
}

Request 2:

format = metadata
metadataHeaders = In-Reply-To,References,Message-ID,Subject
fields = payload/headers

GET https://www.googleapis.com/gmail/v1/users/me/messages/15071b210a1ac883?format=metadata&metadataHeaders=In-Reply-To&metadataHeaders=References&metadataHeaders=Message-ID&metadataHeaders=Subject&fields=payload%2Fheaders

Response:

{
 "payload": {
  "headers": [
   {
    "name": "In-Reply-To",
    "value": "<CADsZLRyej6wRwCNYv91+dBu9uYhuqYo4pEqOpt41NftXJJqC7g@mail.gmail.com>"
   },
   {
    "name": "References",
    "value": "<CADsZLRyej6wRwCNYv91+dBu9uYhuqYo4pEqOpt41NftXJJqC7g@mail.gmail.com>"
   },
   {
    "name": "Message-ID",
    "value": "<CADsZLRzipMRrQv-A9m-r-EJafXXm1eS9ihw3ZD5g8ybfj+LYeg@mail.gmail.com>"
   },
   {
    "name": "Subject",
    "value": "Re: Perculiar"
   }
  ]
 }
}

All that is left is to create a message with all this data in the right places:

Request 3:

POST https://www.googleapis.com/upload/gmail/v1/users/me/messages/send?uploadType=multipart
Content-Type: multipart/related; boundary="foo_bar_baz"

--foo_bar_baz
Content-Type: application/json; charset=UTF-8

{
  "threadId": "15071a4886871a10"
}

--foo_bar_baz
Content-Type: message/rfc822

Content-Type: multipart/mixed; boundary="foo_bar"
In-Reply-To: <CADsZLRzipMRrQv-A9m-r-EJafXXm1eS9ihw3ZD5g8ybfj+LYeg@mail.gmail.com>
References: <CADsZLRyej6wRwCNYv91+dBu9uYhuqYo4pEqOpt41NftXJJqC7g@mail.gmail.com> <CADsZLRzipMRrQv-A9m-r-EJafXXm1eS9ihw3ZD5g8ybfj+LYeg@mail.gmail.com>
From: emtholin@gmail.com
To: emtholin@gmail.com
Subject: Re: Perculiar

--foo_bar
Content-Type: text/html; charset="UTF-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit

<div dir="ltr"><b> This is where the message text goes </b></div>

--foo_bar
Content-Type: image/png
MIME-Version: 1.0
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="cool.png"

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

--foo_bar--
--foo_bar_baz--

This results in a new message with an attachment threaded like before:

Answer 2

To get it to thread on the senders side also you need to specify the Message.threadId field as part of your send() call. (That does not currently happen automatically, unfortunately.)