google_storage

Example google_storage

Connects with Google Cloud Storage using OAuth2, takes pictures every 20 seconds and upload it to the cloud.

Requirements

• A Firebase project or a Google Cloud Storage bucket
• An OAuth2 client ID of type other in google cloud credential manager.
• An authorized device_code

This example relies on Google's API. Recommended read:

• documentation for OAuth2ForDevice
• documentation about OAuth2 protocol

Steps

Step 0: Create a Firebase project / GCP project

This is step is a no-brainer.

Step 1: Configure your Google Credential

Register a new OAuth client ID credential in google cloud credential manager. Make sure the right project is selected.

Make sure to select application type as TVs and Limited Input devices:

Save the newly generated client ID and client secret:

Be aware that personal data show in examples will not work you.

Step 2: Create a device_code

Run the following HTTP request to obtain your device_code:

curl -X POST \
  https://accounts.google.com/o/oauth2/device/code \
  -d 'scope=[scope1 scope2 ...]&client_id=[client_id]'

For this example we need Cloud Storage API scope: https://www.googleapis.com/auth/devstorage.read_write, and our previous generated cliend_id: 188222768791-lb424a2dqca59bohh1uhitnbanl48usi.apps.googleusercontent.com.

If you need other scopes, check this URL for available scopes.

You request should be someting like this:

curl -X POST \
  https://accounts.google.com/o/oauth2/device/code \
  -d 'scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fdevstorage.read_write&client_id=188222768791-lb424a2dqca59bohh1uhitnbanl48usi.apps.googleusercontent.com'

Note that all characters were URI encoded.

And then we finnaly get our device_code:

{
  "device_code": "AH-1Ng2V5ESScqq8dz6Ena7n8-gYFKBAl2Y5QZfNemoEYFtOj_I-zNdNHpaEgjflkhT-qBWFCzyC_JfEsxKbfyh5WoPkMyDW1Q",
  "user_code": "ZPZ-KSH-WBV",
  "expires_in": 1800,
  "interval": 5,
  "verification_url": "https://www.google.com/device"
}

Step 3: Autorize your device

With your device_code in hands, just navigate to verification_url.

Next step you will see OAuth's scope autorization screen. It shows a summary of all permissions necessary.

Be aware: following the OAuth protocol, this kind of application have access to services binded to a given gmail account.

Step 4: Get a refresh_token

Run the following HTTP request to obtain your refresh_token:

curl -X POST \
  https://www.googleapis.com/oauth2/v4/token \
  -d 'client_secret=[client_secret]&client_id=[client_id]&device_code=[device_code]&grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Adevice_code'

You request should be someting like this:

curl -X POST \
  https://www.googleapis.com/oauth2/v4/token \
  -d 'client_secret=SbtStO7IgIcIJDrLEg7inTXD&client_id=188222768791-lb424a2dqca59bohh1uhitnbanl48usi.apps.googleusercontent.com&device_code=AH-1Ng2V5ESScqq8dz6Ena7n8-gYFKBAl2Y5QZfNemoEYFtOj_I-zNdNHpaEgjflkhT-qBWFCzyC_JfEsxKbfyh5WoPkMyDW1Q&grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Adevice_code'

Note that all characters were URI encoded.

You will receive both access_token and refresh_token:

{
    "access_token": "ya29.GluuBlCdOPCXpCkeRZWOqYzYycshVGqTpKR4L5Qc7jgKLuytVWrPqtLeA9jfr9-_oVsIDTthfY-cN2U3Fz0NeMvewb4H3xbSqBsqxOwoC9kFDJiU0nkiy5NwZyED",
    "expires_in": 3600,
    "refresh_token": "1/_SClVR_5IhCA3WDXqyaRoYJFPVU-1yhFhFAPWcFL9XtnJSTfGJhlx4tngrU1wGLO",
    "scope": "https://www.googleapis.com/auth/devstorage.read_write",
    "token_type": "Bearer"
}

Step 5: Burn to KConfig

Besides setting your WiFi SSID and Password via make menuconfig or directly in Kconfig.projbuild, you also need to set GCP_CLIENT_ID, GCP_CLIENT_SECRET, GCP_REFRESH_TOKEN, GCP_DEVICE_CODE, GCP_BUCKET and GCP_PROJECT.

The bucket name can be found on Google Cloud's Storage page.

This example does NOT url encode any parameter. You need to do it before adding they to Kconfig. I.e. replace '1/' in refresh token for '1%2F'.

Notes

All camera pins are configured by default accordingly to this A.I. Thinker document and you can check then inside Kconfig.projbuild.

Make sure to read sdkconfig.defaults file to get a grasp of required configurations to enable PSRAM and set it to 64MBit.