Getting Google Drive APK access_token programatically - google-drive-api

Question

I have a linux OS based custom embedded system. There are cameras connected to my system and i want to use google drive as cloud storage for records that were taken from my cameras.
For that purpose i used almost all google drive api functions successfully by following google drive api rest documentation in
https://developers.google.com/drive/v3/web/about-sdk
Restful api functions require an access_token for authentication purpose in accordance with OAuth2 protocol in HTTP requests. Getting this token requires some one time manual operations.
1- When signed in to google with my account, i had to create a client_id and a client_secure using google developer console.
2- Then i use these credentials to get access_code. In a response to a http request google sends me a url and a grant code.
3- Then i visit the url using a browser, typing grant code and allowing for authentication manually. Then i get access_token and refresh_token with another HTTP request.
4- After that point i can use any api function successfully with given access_token. (and i refresh it if it expires using refresh_token)
My problem is one time manual operations that are made to get tokens. I am making these operation in my computer so making them in my embedded system looks very difficult. But i want to make all the steps (signing in, client_id and client_secure, visiting url, typing grant code and allowing for authentication) in my embedded system.
So, I wonder if it is possible doing all this one time manual process to get access_code without using developer console and a browser? Can i make them programatically?
This is what i tried following oauth2 google official documentation.
After creating client_id and client_Secret i simply used curl for http operations. I wrote following bash code for testing purpose. So It is not self confident and requires some files which can be empty at first and named "access_token", "folder_id", "refresh_token", "myFile" files in the same directory.
#!/bin/bash
# Google Drive API
get_file_id() {
RESPONSE=`curl --silent -H 'GData-Version: 3.0' -H "Authorization: Bearer $ACCESS_TOKEN" \
https://www.googleapis.com/drive/v2/files?q=title+contains+\'$1\'\&fields=items%2Fid`
FILE_ID=`echo $RESPONSE | python -mjson.tool | grep -oP 'id"\s*:\s*"\K(.*)"' | sed 's/"//'`
}
set -e
CLIENT_SECRET="my client_secret"
CLIENT_ID="my_client_id"
BOUNDARY="foo_bar_baz"
SCOPE="https://docs.google.com/feeds"
MIME_TYPE="application/octet-stream"
ACCESS_TOKEN=`cat access_token`
REFRESH_TOKEN=`cat refresh_token`
FOLDER_ID=`cat folder_id`
if [ "$1" == "create_token" ]; then # Usage: <"create_token">
RESPONSE=`curl --silent "https://accounts.google.com/o/oauth2/device/code" -d "client_id=$CLIENT_ID&scope=$SCOPE"`
DEVICE_CODE=`echo "$RESPONSE" | python -mjson.tool | grep -oP 'device_code"\s*:\s*"\K(.*)"' | sed 's/"//'`
USER_CODE=`echo "$RESPONSE" | python -mjson.tool | grep -oP 'user_code"\s*:\s*"\K(.*)"' | sed 's/"//'`
URL=`echo "$RESPONSE" | python -mjson.tool | grep -oP 'verification_url"\s*:\s*"\K(.*)"' | sed 's/"//'`
echo -n "Go to $URL and enter $USER_CODE to grant access to this application. Hit enter when done..."
read
RESPONSE=`curl --silent "https://accounts.google.com/o/oauth2/token" -d "client_id=$CLIENT_ID&client_secret=$CLIENT_SECRET&code=$DEVICE_CODE&grant_type=http://oauth.net/grant_type/device/1.0"`
ACCESS_TOKEN=`echo "$RESPONSE" | python -mjson.tool | grep -oP 'access_token"\s*:\s*"\K(.*)"' | sed 's/"//'`
REFRESH_TOKEN=`echo "$RESPONSE" | python -mjson.tool | grep -oP 'refresh_token"\s*:\s*"\K(.*)"' | sed 's/"//'`
echo "Access Token: $ACCESS_TOKEN"
echo "Refresh Token: $REFRESH_TOKEN"
echo "$ACCESS_TOKEN" > access_token
echo "$REFRESH_TOKEN" > refresh_token
elif [ "$1" == "refresh_token" ]; then # Usage: <"refresh_token">
RESPONSE=`curl --silent "https://accounts.google.com/o/oauth2/token" --data "client_id=$CLIENT_ID&client_secret=$CLIENT_SECRET&refresh_token=$REFRESH_TOKEN&grant_type=refresh_token"`
ACCESS_TOKEN=`echo $RESPONSE | python -mjson.tool | grep -oP 'access_token"\s*:\s*"\K(.*)"' | sed 's/"//'`
echo "Access Token: $ACCESS_TOKEN"
echo "$ACCESS_TOKEN" > access_token
elif [ "$1" == "create_folder" ]; then # Usage: <"create_folder">
FOLDER_NAME=`date "+%F-%T"`
( echo -en "{ \"title\": \"$FOLDER_NAME\", \"mimeType\": \"application/vnd.google-apps.folder\" }\n" ) \
| curl -H 'GData-Version: 3.0' -v "https://www.googleapis.com/drive/v2/files" \
--header "Authorization: Bearer $ACCESS_TOKEN" \
--header "Content-Type: application/json" \
--data-binary "#-"
#save FILE_ID to filde
get_file_id $FOLDER_NAME
echo "$FILE_ID" > folder_id
elif [ "$1" == "upload_file" ]; then # Usage: <"upload_file"> <file name>
( echo -en "--$BOUNDARY\nContent-Type: application/json; charset=UTF-8\n\n{ \"title\": \"$2\", \"parents\": [ { \"id\": \"$FOLDER_ID\" } ] }\n\n--$BOUNDARY\nContent-Type: $MIME_TYPE\n\n" \
&& cat $2 && echo -en "\n\n--$BOUNDARY--\n" ) \
| curl -H 'GData-Version: 3.0' -v "https://www.googleapis.com/upload/drive/v2/files/?uploadType=multipart" \
--header "Authorization: Bearer $ACCESS_TOKEN" \
--header "Content-Type: multipart/related; boundary=\"$BOUNDARY\"" \
--data-binary "#-"
elif [ "$1" == "list_files" ]; then # Usage: <"list_files"> <number of files>
curl -H 'GData-Version: 3.0' -H "Authorization: Bearer $ACCESS_TOKEN" \
https://www.googleapis.com/drive/v2/files?maxResults=$2
elif [ "$1" == "download_file" ]; then # Usage: <"download_file"> <file name>
get_file_id $2
curl -H 'GData-Version: 3.0' -H "Authorization: Bearer $ACCESS_TOKEN" \
https://www.googleapis.com/drive/v2/files/$FILE_ID?alt=media
elif [ "$1" == "get_file" ]; then # Usage: <"get_file"> <file name>
get_file_id $2
curl -H 'GData-Version: 3.0' -H "Authorization: Bearer $ACCESS_TOKEN" \
https://www.googleapis.com/drive/v2/files/$FILE_ID
elif [ "$1" == "delete_file" ]; then # Usage: <"delete_file"> <file name>
get_file_id $2
curl -X Delete -H 'GData-Version: 3.0' -H "Authorization: Bearer $ACCESS_TOKEN" \
https://www.googleapis.com/drive/v2/files/$FILE_ID
elif [ "$1" == "trash_file" ]; then # Usage: <"trash_file"> <file name>
get_file_id $2
curl -d -H 'GData-Version: 3.0' -H "Authorization: Bearer $ACCESS_TOKEN" \
https://www.googleapis.com/drive/v2/files/$FILE_ID/trash
elif [ "$1" == "untrash_file" ]; then # Usage: <"untrash_file"> <file name>
get_file_id $2
curl -d -H 'GData-Version: 3.0' -H "Authorization: Bearer $ACCESS_TOKEN" \
https://www.googleapis.com/drive/v2/files/$FILE_ID/untrash
fi
exit 0
Regards

Answer 1

One way to do this would be to use Domain-Wide Delegation of Authority, a service account. This method works with a JWT for the authentication. The process is explained here: Using OAuth 2.0 for Server to Server Applications
The app would use the service account to authenticate as the id that you want t use to store the drive files.