PLT-7211: Connecting to token metadata registry

packages/token-metadata-client/src/index.ts

@@ -1,26 +1,65 @@
 export interface TokenMetadata {
-  precision: number;
-  symbol: string;
+  /** A human-readable name for the subject, suitable for use in an interface. */
   name: string;
-  network: "mainnet" | "preview" | "preprod";
+  /** A human-readable description for the subject, suitable for use in an interface. */
+  description: string;
+  /** The base16-encoded CBOR representation of the monetary policy script, used to verify ownership. Optional in the case of Plutus scripts as verification is handled elsewhere. */
+  policy?: string;
+  /** A human-readable ticker name for the subject, suitable for use in an interface. */
+  ticker?: string;
+  /** A HTTPS URL (web page relating to the token). */
+  url?: string;
+  /** A PNG image file as a byte string. */
+  logo?: string;
+  /** How many decimals to the token. */
+  decimals?: number;
 }
 
-export const lookupTokenMetadata = (
+interface TokenMetadataJSONResponse {
+  name: { value: string };
+  description: { value: string };
+  policy?: string;
+  ticker?: { value: string };
+  url?: { value: string };
+  logo?: { value: string };
+  decimals?: { value: number };
+}
+
+const cardano_foundation_server_url =
+  "https://raw.githubusercontent.com/cardano-foundation/cardano-token-registry/master/mappings/";
+const iohk_server_url =
+  "https://raw.githubusercontent.com/input-output-hk/metadata-registry-testnet/master/registry/";
+
+export const lookupTokenMetadata = async (
   policyId: string,
-  tokenName: string
-): Promise<TokenMetadata> =>
-  new Promise((resolve, reject) => {
-    if (policyId === "" && tokenName === "")
-      return resolve({
-        precision: 1e-6,
-        symbol: "₳",
-        name: "Ada",
-        network: "mainnet",
-      });
-    throw reject("not found");
-  });
+  assetName: string,
+  network: "mainnet" | "preview" | "preprod"
+): Promise<TokenMetadata> => {
+  if (policyId === "" && assetName === "") {
+    return {
+      decimals: 6,
+      ticker: network === "mainnet" ? "₳" : "t₳",
+      name: "Ada",
+      description: "Cardano ADA",
+    };
+  } else {
+    const server_url =
+      network === "mainnet" ? cardano_foundation_server_url : iohk_server_url;
+    const response = await fetch(`${server_url}/${policyId + assetName}.json`);
+    const json: TokenMetadataJSONResponse = await response.json();
+    return {
+      name: json.name.value,
+      description: json.description.value,
+      policy: json.policy,
+      ticker: json.ticker?.value,
+      url: json.url?.value,
+      logo: json.logo?.value,
+      decimals: json.decimals?.value,
+    };
+  }
+};
 
 export const formatToken = (
-  { precision, symbol }: TokenMetadata,
+  { decimals, ticker, name }: TokenMetadata,
   value: number
-): string => `${value * precision} ${symbol}`;
+): string => `${value * 10 ** -(decimals || 0)} ${ticker || name}`;

tsconfig.json

@@ -6,6 +6,7 @@
     { "path": "./packages/wallet/src" },
     { "path": "./packages/runtime/client/rest/src" },
     { "path": "./packages/runtime/core/src" },
-    { "path": "./packages/runtime/api/src" }
+    { "path": "./packages/runtime/api/src" },
+    { "path": "./packages/token-metadata-client/src" }
   ]
 }