Supermarket

Supermarket Skill

Search grocery products, find stores, add to cart, and view your profile across all Kroger-family stores (Kroger, Ralphs, Fred Meyer, Harris Teeter, King Soopers, Fry's, QFC, Mariano's, Pick 'n Save, and more) — all through the Kroger API via a hosted OAuth proxy. No API keys or developer accounts needed.

How This Works (Transparency)

This skill uses a hosted OAuth proxy at us-central1-krocli.cloudfunctions.net to handle Kroger API authentication. Here's what it does and doesn't do:

What the proxy handles:

• Stores the Kroger client_id/client_secret (as Firebase secrets — never exposed to the agent)
• Exchanges authorization codes for tokens during login
• Refreshes expired user tokens

Privacy guarantees (verifiable in source):

• User tokens are deleted from Firestore immediately after being returned to the agent (tokenUser.ts:44)
• Login sessions expire after 5 minutes (callback.ts:10)
• Firestore rules deny all direct client access — only server-side Cloud Functions can read/write
• No tokens are logged — only errors use console.error
• The proxy never sees your Kroger username or password (that goes directly to Kroger's OAuth page)

Full source code: The proxy is open source at firebase/functions/src/ in the krocli repository. You can audit every function: authorize.ts, callback.ts, tokenClient.ts, tokenUser.ts, tokenRefresh.ts.

If you don't trust the hosted proxy, see "Self-Hosting" at the bottom of this document.

Architecture

All API calls go through the hosted proxy which handles OAuth credentials. The agent never needs a client_id or client_secret.

Two token types:

• Client token — for public data (products, locations). Obtained automatically.
• User token — for personal data (cart, profile). Requires one-time browser login.

Getting a Client Token

Before searching products or locations, obtain a client token:

curl -s -X POST https://us-central1-krocli.cloudfunctions.net/tokenClient

Response:

{"access_token": "eyJ...", "expires_in": 1800, "token_type": "bearer"}

Cache the access_token for subsequent requests. It expires in 30 minutes.

Searching Products

curl -s -H "Authorization: Bearer ACCESS_TOKEN" \
  -H "Accept: application/json" \
  "https://api.kroger.com/v1/products?filter.term=milk&filter.limit=10"

Query parameters:

Response fields to show the user:

• data[].productId — UPC code
• data[].description — Product name
• data[].brand — Brand name
• data[].items[].price.regular — Price (when locationId provided)
• data[].items[].price.promo — Sale price (when available)
• data[].items[].size — Package size

Finding Store Locations

curl -s -H "Authorization: Bearer ACCESS_TOKEN" \
  -H "Accept: application/json" \
  "https://api.kroger.com/v1/locations?filter.zipCode.near=45202&filter.limit=5"

Query parameters:

Response fields to show the user:

• data[].locationId — Store ID (use for product pricing)
• data[].name — Store name
• data[].address.addressLine1, city, state, zipCode
• data[].phone — Phone number
• data[].hours — Operating hours

User Authentication (for Cart & Profile)

When the user wants to add items to their cart or view their profile, they need to authenticate with Kroger. This is a one-time browser flow.

Step 1: Generate a session ID and send the login link

Generate a random hex session ID (16-32 characters) and present the login URL to the user as a clickable link:

https://us-central1-krocli.cloudfunctions.net/authorize?session_id=SESSION_ID

Tell the user: "Click this link to log in to your Kroger account. Once you see 'Login successful', come back here and let me know."

Step 2: Poll for tokens

After the user says they've logged in, poll for their tokens:

curl -s "https://us-central1-krocli.cloudfunctions.net/tokenUser?session_id=SESSION_ID"

• If {"status": "pending"} with HTTP 202: user hasn't finished yet. Wait and retry.
• If HTTP 200: tokens are returned. Cache access_token and refresh_token.

{
  "access_token": "eyJ...",
  "refresh_token": "abc...",
  "expires_in": 1800,
  "token_type": "bearer"
}

Step 3: Use the user token

The user token is needed for cart and profile endpoints.

Adding to Cart

Requires user token from authentication above.

curl -s -X PUT \
  -H "Authorization: Bearer USER_ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  "https://api.kroger.com/v1/cart/add" \
  -d '{"items": [{"upc": "0011110838049", "quantity": 1}]}'

Request body:

{
  "items": [
    {"upc": "PRODUCT_ID", "quantity": 1}
  ]
}

HTTP 204 means success (no response body).

Viewing Profile

Requires user token.

curl -s -H "Authorization: Bearer USER_ACCESS_TOKEN" \
  -H "Accept: application/json" \
  "https://api.kroger.com/v1/identity/profile"

Refreshing an Expired User Token

If a user token returns 401, refresh it:

curl -s -X POST \
  -H "Content-Type: application/json" \
  "https://us-central1-krocli.cloudfunctions.net/tokenRefresh" \
  -d '{"refresh_token": "REFRESH_TOKEN"}'

Response includes new access_token and refresh_token. Cache both.

Token Management Summary

Error Handling

Typical Workflows

"Search for milk near me"

1. Get client token via POST /tokenClient
2. Ask user for ZIP code (or use a previously known one)
3. Find nearest store via locations API
4. Search products with filter.locationId for local pricing

"Add bananas to my Kroger cart"

1. Check if user token is cached; if not, start login flow
2. Search for "bananas" to get the UPC
3. Confirm product with user
4. PUT /cart/add with the UPC

"What Kroger stores are near 90210?"

1. Get client token
2. Search locations with filter.zipCode.near=90210
3. Format results with name, address, hours

Token Persistence

After a successful user login, save the refresh token and preferred ZIP code to your long-term memory so the user doesn't have to log in again next session.

After login, remember:

• kroger_refresh_token: the refresh_token from the login flow
• kroger_zip_code: the user's preferred ZIP code (if provided)
• kroger_store_id: the user's preferred store locationId (if identified)

At the start of a session, check your memory for a saved kroger_refresh_token. If found:

1. Call POST /tokenRefresh with the saved refresh_token
2. If it succeeds, use the new access_token — no login needed
3. If it fails (e.g. token revoked), clear the saved token and start a fresh login flow

Important: Only save the refresh_token, never the access_token (it expires in 30 minutes and is useless to persist).

Self-Hosting the Proxy

If you prefer not to use the hosted proxy, you can run your own. The full source is in the krocli repo under firebase/.

Option 1: Deploy your own Firebase proxy

1. Create a Kroger developer app at developer.kroger.com
   • Scopes: product.compact, cart.basic:write, profile.compact
   • Redirect URI: https://YOUR-PROJECT.cloudfunctions.net/callback
2. Clone the repo and set up Firebase:

   git clone https://github.com/BLANXLAIT/krocli.git
   cd krocli/firebase
   firebase init
   firebase functions:secrets:set KROGER_CLIENT_ID
   firebase functions:secrets:set KROGER_CLIENT_SECRET
   

3. Update CALLBACK_URL in callback.ts and authorize.ts to point to your project
4. Deploy:

   firebase deploy --only functions,firestore:rules
   

5. Replace all us-central1-krocli.cloudfunctions.net URLs in this skill with your own project URL

Option 2: Use the krocli CLI directly (no proxy at all)

If you have Go installed, you can skip the proxy entirely:

go install github.com/blanxlait/krocli/cmd/krocli@latest
krocli auth credentials set /path/to/your/kroger-creds.json
krocli products search --term "milk"
krocli auth login   # browser OAuth, tokens stored in OS keyring
krocli cart add --upc 0011110838049

In this mode, all API calls go directly to api.kroger.com using your own credentials. No proxy involved. Tokens are stored locally in your OS keyring.