👾External

Yours Protocol allows your dapp to provide on-chain utility to tokens that have their ownership on external EVM blockchains. This section will describe how you can set that up. For more higher-level information about how the tokens are synced, see the External Tokens documentation.

Configuration

```yaml
definitions:
  - &receiver # Base configuration for a chain that receives messages
    gtx:
      modules:
        - "net.postchain.d1.icmf.IcmfReceiverGTXModule"
    sync_ext:
      - "net.postchain.d1.icmf.IcmfReceiverSynchronizationInfrastructureExtension"

blockchains:
  megayours_tg:
    module: main
    config:
      <<: *receiver
      icmf:
        receiver:
          local:
            - bc-rid: x"0C034CAB6586CD4F38EAF56721905BA388762906CA75C0C67650F9AB2E69C7BC"
              topic: 'L_yours_external_amoy_c5f7f51e9de3b92a5f2ad9fd41c9e58c0cd2f2a6'
            - bc-rid: x"0C034CAB6586CD4F38EAF56721905BA388762906CA75C0C67650F9AB2E69C7BC"
              topic: 'L_yours_external_amoy_8d3a7c58f5b90b669e076ae4b01247c1561559b5'
            - bc-rid: x"0C034CAB6586CD4F38EAF56721905BA388762906CA75C0C67650F9AB2E69C7BC"
              topic: 'L_yours_external_amoy_7ddf0ca2e6ef5dac06ed79864e2cb40659b38401'
            - bc-rid: x"0C034CAB6586CD4F38EAF56721905BA388762906CA75C0C67650F9AB2E69C7BC"
              topic: 'L_yours_external_amoy_6721b9f19a1667e77107581ef79b9f2f106e81e0'
            - bc-rid: x"0C034CAB6586CD4F38EAF56721905BA388762906CA75C0C67650F9AB2E69C7BC"
              topic: 'L_yours_external_amoy_687b124886f203197ce68dc0ff14827dd13769ed'

libs:
  ft4:
    registry: https://gitlab.com/chromaway/ft4-lib.git
    path: rell/src/lib/ft4
    tagOrBranch: v1.0.0r
    rid: x"FA487D75E63B6B58381F8D71E0700E69BEDEAD3A57D1E6C1A9ABB149FAC9E65F"
    insecure: false
  iccf:
    registry: https://gitlab.com/chromaway/core/directory-chain
    path: src/iccf
    tagOrBranch: 1.32.2
    rid: x"1D567580C717B91D2F188A4D786DB1D41501086B155A68303661D25364314A4D"
    insecure: false
  icmf:
    registry: https://gitlab.com/chromaway/core/directory-chain
    path: src/messaging/icmf
    tagOrBranch: 1.32.2
    rid: x"19D6BC28D527E6D2239843608486A84F44EDCD244E253616F13D1C65893F35F6"
  yours:
    registry: [e-mail]:megayours/yours-protocol.git
    path: src/lib/yours
    tagOrBranch: main
    rid: x"B85DF44B4C7A4A94B871547EF5759E1356FCD19269419AF500A7586156B4B6D6"
    insecure: false
```

It is very easy to consume external tokens, the additional steps involved are:

1. Include the ICMF modules

2. Installing the icmf library

3. Configuring which external tokens you want to listen to

Contracts

The Gamma chain, which in our case here we specified with bc-rid x"0C034CAB6586CD4F38EAF56721905BA388762906CA75C0C67650F9AB2E69C7BC" broadcasts events for a contract on a topic basis.

In the example above we are subscribing to 5 NFT contracts and all of them on Amoy Polygon testnet.