Announcements/server/src/app.js

const express = require("express");
const {
  createDetailedHealthRouter,
  createHealthRouter,
} = require("./health/routes");
const { createAssetRouter } = require("./assets/routes");
const { createMediaRouter } = require("./assets/media-routes");
const { createAssetService } = require("./assets/service");
const { createPlaybackService } = require("./playback");
const { createPlaybackRouter } = require("./playback/routes");
const {
  createPlaylistRouter,
  createPlaylistService,
} = require("./playlists");
const { createSettingsRouter } = require("./settings/routes");
const { createSettingsService } = require("./settings/service");

function safeNotifier(notifier, logger, failureMessage) {
  const warn = (error) => {
    try {
      logger?.warn?.(failureMessage, error);
    } catch {
      // A best-effort notification or warning must not undo a database commit.
    }
  };
  return (event) => {
    try {
      const result = notifier(event);
      result?.catch?.(warn);
    } catch (error) {
      warn(error);
    }
  };
}

function createApp({
  config,
  database,
  imageProcessor,
  lifecycle,
  logger = console,
  migrations,
  now = Date.now,
  onPlaylistsChanged = () => {},
  playbackService: suppliedPlaybackService,
  storage,
}) {
  const app = express();
  const notifyPlaylistsChanged = safeNotifier(
    onPlaylistsChanged,
    logger,
    "Playlist invalidation notification failed",
  );
  const playbackService =
    suppliedPlaybackService ||
    createPlaybackService({
      database,
      now,
      onActivationChanged: notifyPlaylistsChanged,
    });
  if (!suppliedPlaybackService) {
    playbackService.initialize();
  }
  const reconcilePlaybackDomain = (change) =>
    playbackService.domainChanged(change);
  const reconcileBeforeDomainChange = () =>
    playbackService.reconcile("before_domain_change");
  const notifyPlaylistMutation = (change) => {
    reconcilePlaybackDomain(change);
    const publicChange = { ...change };
    delete publicChange.invalidBoundaryChanged;
    notifyPlaylistsChanged(publicChange);
  };
  const settingsService = createSettingsService(database);
  const assetService = createAssetService({
    database,
    imageProcessor,
    storage,
  });
  const playlistService = createPlaylistService({
    database,
    now,
    onBeforeChange: reconcileBeforeDomainChange,
    onChanged: notifyPlaylistMutation,
  });
  app.locals.playbackService = playbackService;

  app.disable("x-powered-by");
  app.set("trust proxy", config.trustProxy);
  app.use(express.json({ limit: "1mb" }));

  app.get("/api", (request, response) => {
    response.json({ name: "Announcements API", version: 2 });
  });
  app.use(
    "/health",
    createHealthRouter({ database, lifecycle, migrations, storage }),
  );
  const detailedHealthRouterOptions = {
    config,
    database,
    lifecycle,
    migrations,
    storage,
  };
  app.use(
    "/api/health",
    createDetailedHealthRouter(detailedHealthRouterOptions),
  );
  app.use(
    "/api/status",
    createDetailedHealthRouter(detailedHealthRouterOptions),
  );
  app.use(
    "/api/settings",
    createSettingsRouter(settingsService, {
      onBeforePlaybackDomainChange: reconcileBeforeDomainChange,
      onPlaylistsChanged: notifyPlaylistsChanged,
      onPlaybackDomainChanged: reconcilePlaybackDomain,
    }),
  );
  app.use(
    "/api/assets",
    createAssetRouter({
      assetService,
      onBeforePlaybackDomainChange: reconcileBeforeDomainChange,
      onPlaylistsChanged: notifyPlaylistsChanged,
      onPlaybackDomainChanged: reconcilePlaybackDomain,
      processingConfig: config.processing,
    }),
  );
  app.use(
    "/api/playlists",
    createPlaylistRouter(playlistService, {
      playbackService,
    }),
  );
  app.use("/api/playback", createPlaybackRouter(playbackService));
  app.use("/media", createMediaRouter(assetService));

  app.use((request, response) => {
    response.status(404).json({
      error: {
        code: "NOT_FOUND",
        message: "Route not found",
      },
    });
  });

  app.use((error, request, response, next) => {
    if (response.headersSent) {
      next(error);
      return;
    }

    if (error instanceof SyntaxError && error.status === 400 && "body" in error) {
      response.status(400).json({
        error: {
          code: "INVALID_JSON",
          message: "Request body must contain valid JSON",
        },
      });
      return;
    }

    const statusCode = error.statusCode || 500;
    response.status(statusCode).json({
      error: {
        code: error.code || "INTERNAL_ERROR",
        message:
          statusCode >= 500 ? "An internal server error occurred" : error.message,
        ...(error.details ? { details: error.details } : {}),
      },
    });
  });

  return app;
}

module.exports = {
  createApp,
};