SmapiAuthTokens that expire, with sonos refreshAuthToken functionality (#81)

Bearer token to Authorization header for stream requests
Versioned SMAPI Tokens

src/api_tokens.ts

@@ -0,0 +1,30 @@
+import crypto from "crypto";
+
+export interface APITokens {
+  mint(authToken: string): string;
+  authTokenFor(apiToken: string): string | undefined;
+}
+
+
+export const sha256 = (salt: string) => (value: string) => crypto
+  .createHash("sha256")
+  .update(`${value}${salt}`)
+  .digest("hex")
+
+
+export class InMemoryAPITokens implements APITokens {
+  tokens = new Map<string, string>();
+  minter;
+
+  constructor(minter: (authToken: string) => string = sha256('bonob')) {
+    this.minter = minter
+  }
+
+  mint = (authToken: string): string => {
+    const accessToken = this.minter(authToken);
+    this.tokens.set(accessToken, authToken);
+    return accessToken;
+  }
+
+  authTokenFor = (apiToken: string): string | undefined => this.tokens.get(apiToken);
+}