This template allows you to create a front-end application that connects to a Substrate node back-end with minimal configuration. To learn about Substrate itself, visit the Substrate Developer Hub.
The template is built with Create React App and Polkadot js API. Familiarity with these tools will be helpful, but the template strives to be self-explanatory.
The codebase is installed using git and yarn. This tutorial assumes you have installed yarn globally prior to installing it within the subdirectories. For the most recent version and how to install yarn, please refer to yarn documentation and installation guides.
# Clone the repository
yarn install
You can start the template in development mode to connect to a locally running node
yarn start
You can also build the app in production mode,
yarn build
and open build/index.html
in your favorite browser.
The template's configuration is stored in the src/config
directory, with
common.json
being loaded first, then the environment-specific json file,
and finally environment variables, with precedence.
development.json
affects the development environmenttest.json
affects the test environment, triggered inyarn test
command.production.json
affects the production environment, triggered inyarn build
command.
Some environment variables are read and integrated in the template config
object,
including:
REACT_APP_PROVIDER_SOCKET
overridingconfig[PROVIDER_SOCKET]
REACT_APP_DEVELOPMENT_KEYRING
overridingconfig[DEVELOPMENT_KEYRING]
More on React environment variables.
When writing and deploying your own front end, you should configure:
- Custom types as JSON in
src/config/types.json
. See Extending types. PROVIDER_SOCKET
insrc/config/production.json
pointing to your own deployed node.DEVELOPMENT_KEYRING
insrc/config/common.json
be set tofalse
. See Keyring.
When using port 31001 use https endpoint use the loopback address ie https://127.0.0.1:31001
- Replace <API_HOST> of src/config/common.json with the endpoint to openwhisk gateway.
- Create a firebase.google.com project
- Create a Web App using https://console.firebase.google.com/project/<PROJECT_NAME>/settings/general
- Add the generated config to src/sw.js and src/config/firebase.js
There are two ways to specify it:
- With
PROVIDER_SOCKET
in{common, development, production}.json
. - With
rpc=<ws or wss connection>
query paramter after the URL. This overrides the above setting.
The custom hook useSubstrate
provides access to the Polkadot js API and thus the
keyring and the blockchain itself. Specifically it exposes this API.
{
socket,
types,
keyring,
keyringState,
api,
apiState,
}
socket
- The remote provider socket it is connecting to.types
- The custom types used in the connected node.keyring
- A keyring of accounts available to the user.keyringState
- One of"READY"
or"ERROR"
states.keyring
is valid only whenkeyringState === "READY"
.api
- The remote api to the connected node.apiState
- One of"CONNECTING"
,"READY"
, or"ERROR"
states.api
is valid only whenapiState === "READY"
.
The TxButton handles basic query and transaction requests to the connected node. You can reuse this component for a wide variety of queries and transactions. See src/Transfer.js for a transaction example and src/ChainState.js for a query example.
The Account Selector provides the user with a unified way to select their account from a keyring. If the Balances module is installed in the runtime, it also displays the user's token balance. It is included in the template already.