aps_get_token

Instructions

Implementation Reference

• src/index.ts:1023-1030 (handler)

  The handler function that executes the 'aps_get_token' tool logic. It calls the internal token() function which prefers a cached 3-legged token, falling back to a 2-legged token via getApsToken(), then returns a success message with the token length.

  // ── aps_get_token ────────────────────────────────────────────
  if (name === "aps_get_token") {
    const t = await token();
    return ok(
      `2‑legged token obtained (length ${t.length}). ` +
      "All other tools use this token automatically – you don't need to pass it.",
    );
  }

• src/index.ts:167-175 (schema)

  The input schema definition for 'aps_get_token'. It declares the tool name, description, and input schema (empty object, no parameters required).

  // 1 ── aps_get_token
  {
    name: "aps_get_token",
    description:
      "Get a 2‑legged access token for Autodesk Platform Services (APS). " +
      "Use this to verify that credentials are configured correctly. " +
      "The token is cached and auto‑refreshed by all other tools, so you rarely need to call this explicitly.",
    inputSchema: { type: "object" as const, properties: {} },
  },

• src/index.ts:1588-1588 (registration)

  The tool is registered in the TOOLS array (which is passed to ListToolsRequestSchema handler), making 'aps_get_token' available as an MCP tool.

  server.setRequestHandler(ListToolsRequestSchema, async () => ({ tools: TOOLS }));

• src/index.ts:112-117 (helper)

  The internal token() helper function used by the handler. Prefers a valid 3-legged token (user context) via getValid3loToken(), otherwise falls back to a 2-legged (app context) token via getApsToken() from aps-auth.ts.

  async function token(): Promise<string> {
    requireApsEnv();
    const three = await getValid3loToken(APS_CLIENT_ID, APS_CLIENT_SECRET);
    if (three) return three;
    return getApsToken(APS_CLIENT_ID, APS_CLIENT_SECRET, APS_SCOPE || undefined);
  }

• src/aps-auth.ts:68-108 (helper)

  The core getApsToken() function that obtains a 2-legged OAuth access token from APS. It uses client credentials grant, caches the token in memory until near expiry, and defaults to 'data:read' scope.

  export async function getApsToken(
    clientId: string,
    clientSecret: string,
    scope?: string
  ): Promise<string> {
    const effectiveScope = (scope?.trim() || DEFAULT_SCOPE);
    const now = Date.now();
    if (
      cachedToken &&
      cachedToken.expiresAt > now + 60_000 &&
      cachedToken.scope === effectiveScope
    ) {
      return cachedToken.token;
    }
  
    const body = new URLSearchParams({
      grant_type: "client_credentials",
      client_id: clientId,
      client_secret: clientSecret,
      scope: effectiveScope,
    });
  
    const res = await fetch(APS_TOKEN_URL, {
      method: "POST",
      headers: { "Content-Type": "application/x-www-form-urlencoded" },
      body: body.toString(),
    });
  
    if (!res.ok) {
      const text = await res.text();
      throw new Error(`APS token failed (${res.status}): ${text}`);
    }
  
    const data = (await res.json()) as ApsTokenResponse;
    cachedToken = {
      token: data.access_token,
      expiresAt: now + (data.expires_in - 60) * 1000,
      scope: effectiveScope,
    };
    return data.access_token;
  }