google-group-import.sh

#!/bin/bash

#1) on https://console.developers.google.com/ register project, enable Groups Migration API, and create OAuth2 credentials.
#2) set the client_id and client_secret variables below to the values provided when creating the OAuth2 credentials.
#3) make copies of the Client ID and Client Secret for the OAuth2 credentials and use them
client_id="..."
client_secret="...."

#4) get authorization code at the following link using web browser
#  (make sure you sign in with an account that has access to Google Groups you are importing to).
#
#   you will need to replace [CLIENT_ID] with the previously obtained Client ID
#
#       https://accounts.google.com/o/oauth2/auth?client_id=[CLIENT_ID]&redirect_uri=urn:ietf:wg:oauth:2.0:oob&scope=https://www.googleapis.com/auth/apps.groups.migration&response_type=code
#

#5) use the following command to obtain a OAuth2.0 Refresh Token
#
#   you will need to replace [AUTH_CODE] with the value obtained in step #4 and
#   replace [CLIENT_ID] and [CLIENT_SECRET] with the values obtained in step #1
#
#       curl --request POST --data "code=[AUTH_CODE]&client_id=[CLIENT_ID]&client_secret=[CLIENT_SECRET]&redirect_uri=urn:ietf:wg:oauth:2.0:oob&grant_type=authorization_code" https://accounts.google.com/o/oauth2/token
#
#6) set the refresh_token below with the value returned
refresh_token="......"

#7) you may now run the import.  sometimes the process will stop.  if that
#   happens, just wait 5 seconds or so and then run it again.  it will resume
#   where it left off.
#
#   for long running imports, the access token will be refreshed when there is
#   less than 5 minutes (300 seconds) left until its expiration.  if the
#   messages you are importing are really large or your connection really slow
#   such that they take longer than 5 minutes to import you may want to adjust
#   the line in the code below.
#
#   finally it should be mentioned that Google does not provie a particularly
#   fast way to accomplish this since it does not support parallel uploads
#   to the same Google Groups archive.  if parallel uploads were allowed the
#   code could be optimized to take advantage.  the only thing that would need
#   to be encounted for is that message threads need to be uploaded in order.
#   this means the only topic threads could be run in parallel.

function usage() {
  (
    echo "usage: $0 <group-address> <mbox-dir>"
  ) >&2
  exit 5
}

GROUP="$1"
shift
MBOX_DIR="$1"
shift

[ -z "$GROUP" -o -z "$MBOX_DIR" ] && usage

token=$(curl -s --request POST --data "client_id=$client_id&client_secret=$client_secret&refresh_token=$refresh_token&grant_type=refresh_token" https://accounts.google.com/o/oauth2/token | sed -n "s/^\s*\"access_token\":\s*\"\([^\"]*\)\",$/\1/p")

# create done folder if it doesn't already exist
DONE_FOLDER=$MBOX_DIR/../done
mkdir -p $DONE_FOLDER

i=0
for file in $MBOX_DIR/*; do
  echo "importing $file"
  response=$(curl -s -H"Authorization: Bearer $token" -H'Content-Type: message/rfc822' -X POST "https://www.googleapis.com/upload/groups/v1/groups/$GROUP/archive?uploadType=media" --data-binary @${file})
  result=$(echo $response | grep -c "SUCCESS")
  # check to see if it worked
  if [[ $result -eq 0 ]]; then
    echo "upload failed on file $file.  please run command again to resume."
    exit 1
  fi

  # it worked!  move message to the done folder
  mv $file $DONE_FOLDER/

  ((i=i+1))
  if [[ $i -gt 9 ]]; then
    expires_in=$(curl -s "https://www.googleapis.com/oauth2/v1/tokeninfo?access_token=$token" | sed -n "s/^\s*\"expires_in\":\s*\([0-9]*\),$/\1/p")
    if [[ $expires_in -lt 300 ]]; then
      # refresh token
      echo "Refreshing token..."
      token=$(curl -s --request POST --data "client_id=$client_id&client_secret=$client_secret&refresh_token=$refresh_token&grant_type=refresh_token" https://accounts.google.com/o/oauth2/token | sed -n "s/^\s*\"access_token\":\s*\"\([^\"]*\)\",$/\1/p")
    fi
    i=0
  fi
done