Detailed description of how the MetaMask plugin works and its configuration.

Overview

This plugin allows to sign transactions using the MetaMask browser extension.

Quick start

sys.ui.sendMessage({
  scope: 'plugin:metamask',
  name: 'sendTransaction',
  data: {gas: ..., data: ..., ...},  // this is the tx data
  callbacks: {
    approved: function(msg, res) {
      sys.logs.debug("tx hash: "+res.txHash);
      sys.logs.debug("original msg: "+JSON.stringify(msg));
    },
    declined: function(msg, res) {
      sys.logs.debug("declined: "+res.error);
      sys.logs.debug("original msg: "+JSON.stringify(msg));
    },
    error: function(msg, res) {
      sys.logs.debug("error code: "+res.errorCode);
      sys.logs.debug("error: "+res.error);
      sys.logs.debug("original msg: "+JSON.stringify(msg));        
    }
  }
});

This script sends a transaction to MetaMask (in the data field) that need to be confirmed by the user. If the user confirms the transaction, the approved callback gets executed. Otherwise, if the user declines the transaction or there is an error, the declined callback is executed.

If there are other errors, the error callback will be called. For example if the account is not configured in MetaMask, an invalidAccount error will be returned, or invalidNetwork if the network MetaMask is connected to is different than the network requested.

Configuration

There is no configuration for this plugin, however the app must be running in a browser with the MetaMask extension and at there must be an account logged in.

Inbound events

Send transaction

sys.ui.sendMessage({
  scope: 'plugin:metamask',
  name: 'sendTransaction',
  data: {gas: ..., data: ..., ...},  // this is the tx data
  callbacks: {
    approved: function(msg, res) {
      sys.logs.debug("tx hash: "+res.txHash);
      sys.logs.debug("original msg: "+JSON.stringify(msg));
    },
    declined: function(msg, res) {
      sys.logs.debug("error: "+res.error);
      sys.logs.debug("original msg: "+JSON.stringify(msg));
    }
  }
});

Sends a transaction to be signed and sent to the network using the MetaMask plugin. The tx data should be in data (see eth.sendTransaction for more information), while you can pass two callbacks:

  • approved: the user approved the transaction and it was submitted to the network. You should check the status of the transaction to see if it was confirmed. Parameter msg contains the original message sent to the plugin (where you can add more fields if you need them in the callback) while res contains the tx object and txHash.
  • declined: the user didn’t approve the transaction or there was a problem and the tx could not be submitted to the network. msg contains the original message sent to the plugin and you could find the error in res.error.
  • error: there are errors with the account or network. These are the possible error codes:
    • invalidAccount: if the account to sign the transaction is not configured in MetaMask
    • invalidNetwork: if the network MetaMask is connected to is different than the network requested

Sign data

sys.ui.sendMessage({
  scope: 'plugin:metamask',
  name: 'signData',
  data: '0x000......',  // this is the tx data
  callbacks: {
    approved: function(msg, res) {
      sys.logs.debug("signed: "+res.signedData);
      sys.logs.debug("original msg: "+JSON.stringify(msg));
    },
    declined: function(msg, res) {
      sys.logs.debug("error: "+res.error);
      sys.logs.debug("original msg: "+JSON.stringify(msg));
    }
  }
});

Signs data using the MetaMask plugin. The data to sign should be in data while you can pass two callbacks:

  • approved: the user approved the transaction and it was signed. You can find the signed data in res.signedData.
  • declined: the user didn’t approve the transaction or there was a problem signing the data. You can find the error in res.error.
  • error: there are errors with the account. These are the possible error codes:
    • invalidAccount: if the account to sign the transaction is not configured in MetaMask

Get config

sys.ui.sendMessage({
  scope: 'plugin:metamask',
  name: 'getConfig',
  callbacks: {
    response: function(msg, res) {
      sys.logs.debug("config: "+JSON.stringify(res));
      sys.logs.debug("original msg: "+JSON.stringify(msg));
    }
  }
});

Returns the configuration of MetaMask. This is useful if you want to check configured accounts or the network MetaMask is currently configured to. It supports the following callback:

  • response: the config is sent in the res parameter. This parameter has the following structure: 
    {
  "netId": 1, 
  "defaultAccount": "0x1...", 
  "accounts": ["0x1...", "0x2..."]
}

Outbound events

This plugin does not have outbound events.

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