Testing the dapp

We test the dapp manually by starting the corresponding blockchains, creating a subscription, and using it to access the warehouse.

First, ensure that the blockchains are defined in the following order to align with the internal IDs used in this course:

chromia.yml

blockchains:
  subscription_chain: # Chain id 1
  ...
  digital-warehouse-chain: # Chain id 2
  ...

To start the blockchains, you need to run the node from the project folder in a separate terminal window:

chr node start --directory-chain-mock

Expected output of logs:

...
Starting blockchain directory-chain with brid B39406781EE6CA71391B519AA1D3B009DA77A0A63B12DCB2BD4DD59C679E2703 on id 0
Starting blockchain subscription_chain with brid EB0A24835FC5B49CFCB6A9C3DC688FBC7D457455E69B9B2956E7689BC830CA49 on id 1
Starting blockchain digital_warehouse_chain with brid 42C95A7CCDAE9B78524A32428E7B313F60AEB31BA66FF41A0ECE2FCB576D5FF4 on id 2
...

Please note that values of brids can be different on your side.

Let`s save brids into environment variables for convenient reuse in the following steps:

SUBSCRIPTION_CHAIN_BRID=$(curl -s localhost:7740/brid/iid_1) && echo $SUBSCRIPTION_CHAIN_BRID

DIGITAL_WAREHOUSE_BRID=$(curl -s localhost:7740/brid/iid_2) && echo $DIGITAL_WAREHOUSE_BRID

Proceed with the setup by creating a new keypair and storing it in the .chromia/config directory, the default search path for Chromia CLI:

chr keygen --file .chromia/config

Note down the pubkey printed to the console. You will use this as the account ID input for our operations.

Next, attempt to register a new product category to observe that making a transaction towards the digital warehouse will fail:

chr tx -brid $DIGITAL_WAREHOUSE_BRID register_product_category 555 0 --await -cfg .chromia/config

Result

... Operation 'digital_warehouse_chain:register_product_category' failed: No account found

Create a new subscription on the Subscription chain before attempting again.

Now, you can create a new subscription. Replace <pubkey> with the previously generated one:

chr tx -brid $SUBSCRIPTION_CHAIN_BRID subscribe 'x"<digital_warehouse_brid>" '[x"<pubkey>", 0]' --await -cfg .chromia/config

Example for using an environment variable substitution:

chr tx -brid $SUBSCRIPTION_CHAIN_BRID subscribe  'x"'"$DIGITAL_WAREHOUSE_BRID"'"' '[x"021E6EE49D997C6DF7721F87027BB56D7436A9CC78F344AE6FF2E8A08789D37F5A", 0]' --await -cfg .chromia/config

Output should be like this:

transaction with rid F300CBD62F22917145F8594DB63F1780803CD123CA7F89DBE952431409EE2629 was posted CONFIRMED

Note the transaction rid that was output from the command. You can now use the following command to authenticate the digital warehouse. Replace <tx-rid> with the previously obtained value.

This command specifies that we intend to make a transaction towards chain ID 2 and include an iccf-transaction that needs verification against chain 1:

chr tx -brid $DIGITAL_WAREHOUSE_BRID --iccf-source $SUBSCRIPTION_CHAIN_BRID --iccf-tx <tx-rid> authorize  --await -cfg .chromia/config

Now, we should be able to access the system. Let's attempt to register a product category and update the inventory again:

chr tx -brid $DIGITAL_WAREHOUSE_BRID register_product_category 555 0 --await -cfg .chromia/config

chr tx -brid $DIGITAL_WAREHOUSE_BRID update_inventory '[555, 1500, "Got some stuff"]' --await -cfg .chromia/config

Let's wrap up by generating a warehouse report and checking the receipts in the subscription chain:

chr query -brid $DIGITAL_WAREHOUSE_BRID create_report 'from=0' 'to=null' -cfg .chromia/config

Result

[
    "history": [
        [555, [
            ["amount": 1500, "comment": "Got some stuff", "product_category": 555, "transaction": 5]]
            ]
        ],
    "inventory": [
        ["UNIT": "LITRE", "product_category": 555, "stock": 1500]
        ],
    "warehouse_id": 1
]

chr query -brid $SUBSCRIPTION_CHAIN_BRID get_receipts 'account_id=null' 'blockchain_rid=null' 'from=null'

Result

[
    [
        "account_id": x"02EEB43C7400CA3CEBDECF1C8AC049EAC05EB361FE4C003EF6D298DEA792F58526",
        "blockchain_rid": x"237B0EE3C60CBB1884E63F883F8230FED5C804A9C6933B28FD9214D65FD033B5",
        "payment_amount": 30,
        "period": "WEEK",
        "receipt_id": x"6006EFC423E9032EA4C9584CDE791623A015749FD8BA4831457CCE0769BCA20A",
        "timestamp": 1705504892289
    ]
]

Congratulations! You have now learned how to develop a dapp that verifies transactions on another chain to authenticate users.