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Common API

API server intended to connect multiple sources of data:

  1. GraphQL database, populated by Common Indexer.
  2. Archive nodes.
  3. Coingecko API

and exposing it all over unified APIs:

  1. HTTP REST - for request<->response updates.
  2. Websocket - for live updates of the state.

Currently does the following:

  1. Connects to a GraphQL DB and subscribes to:
  • Updates of pools' reserves.
  • Updates of accounts' PSP22 token balances.
  1. Sets up up a HTTP REST server.
  2. Sets up up a Websocket server.

Usage

  1. GraphQL client controlled with three env variables:
  • COMMON_API_GRAPHQL_PROTO - defaults to ws
  • COMMON_API_GRAPHQL_HOST - defaults to localhost
  • COMMON_API_GRAPHQL_PORT - defaults to 4351

Subscription can be turned off by setting env COMMON_API_ENABLE_GRAPHQL=false.

  1. HTTP REST controlled with:
  • COMMON_API_HTTP_PORT specifies the port to which the HTTP server binds to. Defaults to 3000.
  1. Websocket server controlled with:
  • COMMON_API_WS_PORT defaults to 80.

When client connects over websocket - it will push pool updates to the client. Data format description below.

HTTP server, currently, supports the following endpoints:

  • GET /api/v1/price/usd/azero where it serves the A0 price in dollars.
  • GET /api/v1/accounts/:accountId returns account's tokens balances.
  • GET /api/v1/accounts/:accountId/tokens/:token returns a balance of :token under :accountId
  • GET /api/v1/pools returns reserves of all indexed pools.
  • GET /api/v1/pools/:poolId returns reserves of a specific pool
  • GET /api/v1/pools/:poolId/volume?from={from}&to={to} - returns swaps volume for the poolId and requested period.

Configuration

Application's settings can be controlled in three ways (from highest to lowest priority):

  1. Env variables. All variables have a common prefix COMMON_API_. To list all currently set envs run make show-envs in the root directory.
  2. Configuration file. We use node-config for managing the configuration. There's a strict order of loading files so consult the wiki to understand it. Currently, /config directory contains a single local.json file which is quite low on the precedence list.
  3. Defaults.

Demo mode

So called DEMO mode is available. If enabled, Common API will not subscribe to updates from the GraphQL database but send a mocked pool reserves data every second, down to the client.

To enable demo mode, set env variable ENABLE_DEMO_MODE=true or in the config/*.json set the enableDemoMode to true.

Websocket server

Pool data format

Example line sent to WS client:

{
  "id": "5GHmztr49msyhZqp57tkwBwMn7k84yMBmkdxoyozQFzKcKuZ",
  "token0": "5CQyQesQgHj9sPrvtQwnyY6ZWRqBStvTVHMBQWawxNJpuzJS",
  "token1": "5HqSLGvq2qRrAtSqMEcz35rCzr57e1w75cuRGa1CLdNDB3gi",
  "reserves0": "40000000000000",
  "reserves1": "1000000000000000",
  "lastUpdateTimestamp": "1703774206000"
}

so the format is:

interface PoolV2 {
  id: string;
  token0: TokenId;
  token1: TokenId;
  reserves0: bigint;
  reserves1: bigint;
  lastUpdateTimestamp: bigint;
}

where id is the address of the pool.

HTTP REST server

GET /api/v1/price/usd/:ticker - USD token prices

Returns cached USD prices of selected tickers. Prices fetched from Coingecko API and cached up to PRICE_CACHE_INVALIDITY_SECONDS or every hour (default) after which it's invalidated and re-requested. Note that Coingecko itself updates the price every 60 seconds. If we can't query the Coingecko API, we return cached price. If PRICE_CACHE_INVALIDITY_SECONDS is unset, it defaults to 3600 seconds.

Currently supported tickers are:

  • AZERO
  • Bitcoin
  • Ethereum
  • USDT
  • USDC

Example

{ "price": 1.52, "lastUpdateTimestampSeconds": 1710250979 }

GET /api/v1/accounts/:accountId - Account balance

Returns last known state of the :accountId.

Example

{
  "account": "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY",
  "tokens": [
    {
      "account": "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY",
      "amount": "589379986793",
      "token": "5GtkZxmJtKmzygr3CkgFjhmmaGprYNb6XYnMxLRy9BKharh1",
      "lastUpdateBlockHeight": "50928711",
      "lastUpdateTimestamp": "1704291321000",
      "id": "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY-5GtkZxmJtKmzygr3CkgFjhmmaGprYNb6XYnMxLRy9BKharh1"
    },
    {
      "account": "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY",
      "amount": "50000000000000000000",
      "token": "5GUfU2RbEPyGjvojUwoZua3L4X2FiYf213Lddvj3PgFYpAAL",
      "lastUpdateBlockHeight": "50928589",
      "lastUpdateTimestamp": "1704291199000",
      "id": "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY-5GUfU2RbEPyGjvojUwoZua3L4X2FiYf213Lddvj3PgFYpAAL"
    }
  ]
}

GET /api/v1/accounts/:accountId/tokens/:token - Account's specific token state

Returns last known state of :token for :accountId. Example format of the response is:

{
  "account": "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY",
  "amount": "589379986793",
  "token": "5GtkZxmJtKmzygr3CkgFjhmmaGprYNb6XYnMxLRy9BKharh1",
  "lastUpdateBlockHeight": "50928711",
  "lastUpdateTimestamp": "1704291321000",
  "id": "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY-5GtkZxmJtKmzygr3CkgFjhmmaGprYNb6XYnMxLRy9BKharh1"
}

GET /api/v1/pools

Returns all known pools' reserves. Example response is:

{
  "5CanvcAQYZqJ4Qa3LUCqGJZhoa3cDPQxbV22y4DC6DdjXNEd": {
    "id": "5CanvcAQYZqJ4Qa3LUCqGJZhoa3cDPQxbV22y4DC6DdjXNEd",
    "token0": "5E2xuRb3k5h4TdrPAK543TiFBdRvhWSTmz6qT6b1hfq6LA2U",
    "token1": "5HKuP2yvvK2MXst7sgGnG715DqVifidEzwopunjKVtRNA1tf",
    "reserves0": "4000000000000000000000",
    "reserves1": "80000000000000000",
    "lastUpdateTimestamp": "1703774256000"
  },
  "5CtfFw2GBs2MTppjWPWx8ewSwVGpwVyfyj9E4GKf4SetxHJm": {
    "id": "5CtfFw2GBs2MTppjWPWx8ewSwVGpwVyfyj9E4GKf4SetxHJm",
    "token0": "5EAAet9jxK8a4xZk35YeMJgTFUVswEQzbRox32qYK8W2KBCn",
    "token1": "5GUfU2RbEPyGjvojUwoZua3L4X2FiYf213Lddvj3PgFYpAAL",
    "reserves0": "1993375349255972651",
    "reserves1": "3010000000000000000000",
    "lastUpdateTimestamp": "1708125424000"
  }
}

So Map<PoolId, Pool> - a mapping between pool's ID (address) and its last-known state.

GET /api/v1/pools/:poolId - specific pool's reserves

Returns current reserves of a specific pool, identifier by poolId. Example response:

{
  "id": "5CanvcAQYZqJ4Qa3LUCqGJZhoa3cDPQxbV22y4DC6DdjXNEd",
  "token0": "5E2xuRb3k5h4TdrPAK543TiFBdRvhWSTmz6qT6b1hfq6LA2U",
  "token1": "5HKuP2yvvK2MXst7sgGnG715DqVifidEzwopunjKVtRNA1tf",
  "reserves0": "4000000000000000000000",
  "reserves1": "80000000000000000",
  "lastUpdateTimestamp": "1703774256000"
}

GET /api/v1/pools/:poolId/volume?from={from}&to={to} - pool's swap volume

Returns swap volume starting from {from} until {to} (both argument expected to be milliseconds). The server rounds them down to the nearest minute so that we can levarage GraphQL server's caching.

Example response:

{
  "pool": "5Ek4Z1rkEx8aS1oRTekEZ3MtDseurx4ZQV8v56YE6Bj8BqMp",
  "fromMillis": "1",
  "toMillis": "1704294000100",
  "amount0_in": 15000000000000,
  "amount1_in": 0
}

GET /health - health check endpoint

Returns basic information about the Common API configuration.

Response format:

{
      priceCacheEnabled: <boolean>,
      demoModeEnabled: <boolean>,
      graphqlUpdatesEnabled: <boolean>,
    }