Expose Astro's trailingSlash config to plugins via ctx.site

.changeset/expose-trailing-slash.md

@@ -0,0 +1,7 @@
+---
+"emdash": minor
+"@emdash-cms/cloudflare": minor
+"@emdash-cms/sandbox-workerd": minor
+---
+
+Expose the host Astro project's `trailingSlash` config to plugins via `ctx.site.trailingSlash`, so plugins that build absolute URLs (sitemaps, canonical, hreflang) can match the site's routing policy. Available to in-process and sandboxed plugins alike.

packages/cloudflare/src/sandbox/runner.ts

@@ -102,7 +102,12 @@ export class CloudflareSandboxRunner implements SandboxRunner {
 	private plugins = new Map<string, CloudflareSandboxedPlugin>();
 	private options: SandboxOptions;
 	private resolvedLimits: ResolvedLimits;
-	private siteInfo?: { name: string; url: string; locale: string };
+	private siteInfo?: {
+		name: string;
+		url: string;
+		locale: string;
+		trailingSlash?: "always" | "never" | "ignore";
+	};
 
 	constructor(options: SandboxOptions) {
 		this.options = options;
@@ -203,15 +208,25 @@ class CloudflareSandboxedPlugin implements SandboxedPluginInstance {
 	private code: string;
 	private wrapperCode: string | null = null;
 	private limits: ResolvedLimits;
-	private siteInfo?: { name: string; url: string; locale: string };
+	private siteInfo?: {
+		name: string;
+		url: string;
+		locale: string;
+		trailingSlash?: "always" | "never" | "ignore";
+	};
 
 	constructor(
 		manifest: PluginManifest,
 		code: string,
 		loader: WorkerLoader,
 		createBridge: (opts: { props: PluginBridgeProps }) => PluginBridgeBinding,
 		limits: ResolvedLimits,
-		siteInfo?: { name: string; url: string; locale: string },
+		siteInfo?: {
+			name: string;
+			url: string;
+			locale: string;
+			trailingSlash?: "always" | "never" | "ignore";
+		},
 	) {
 		this.id = `${manifest.id}:${manifest.version}`;
 		this.manifest = manifest;

packages/cloudflare/src/sandbox/wrapper.ts

@@ -27,7 +27,12 @@ const COMMENT_CLOSE_RE = /\*\//g;
  */
 export interface WrapperOptions {
 	/** Site info to inject into the context (no RPC needed) */
-	site?: { name: string; url: string; locale: string };
+	site?: {
+		name: string;
+		url: string;
+		locale: string;
+		trailingSlash?: "always" | "never" | "ignore";
+	};
 }
 
 export function generatePluginWrapper(manifest: PluginManifest, options?: WrapperOptions): string {

packages/core/src/astro/integration/index.ts

@@ -412,6 +412,9 @@ export function emdash(config: EmDashConfig = {}): AstroIntegration {
 				// EmDashHead must not access Astro.csp when the host has disabled
 				// Astro's built-in CSP runtime; Astro logs a warning for that access.
 				serializableConfig.astroCspEnabled = Boolean(astroConfig.security.csp);
+				// Expose Astro's trailingSlash routing policy so plugins can build
+				// URLs (sitemap/canonical/hreflang) that match what the site serves.
+				serializableConfig.trailingSlash = astroConfig.trailingSlash;
 				// Extract i18n config from Astro config
 				// Astro locales can be strings OR { path, codes } objects — normalize to paths
 				if (astroConfig.i18n) {

packages/core/src/emdash-runtime.ts

@@ -352,7 +352,12 @@ export interface EmDashRuntimeParts {
 		db: Kysely<Database>;
 		getDb?: () => Kysely<Database>;
 		storage?: Storage;
-		siteInfo?: { siteName?: string; siteUrl?: string; locale?: string };
+		siteInfo?: {
+			siteName?: string;
+			siteUrl?: string;
+			locale?: string;
+			trailingSlash?: "always" | "never" | "ignore";
+		};
 	};
 	runtimeDeps: RuntimeDependencies;
 	pipelineRef: { current: HookPipeline };
@@ -534,7 +539,12 @@ export class EmDashRuntime {
 		db: Kysely<Database>;
 		getDb?: () => Kysely<Database>;
 		storage?: Storage;
-		siteInfo?: { siteName?: string; siteUrl?: string; locale?: string };
+		siteInfo?: {
+			siteName?: string;
+			siteUrl?: string;
+			locale?: string;
+			trailingSlash?: "always" | "never" | "ignore";
+		};
 	};
 	/** Dependencies needed for exclusive hook resolution */
 	private runtimeDeps: RuntimeDependencies;
@@ -1106,7 +1116,14 @@ export class EmDashRuntime {
 		const storage = EmDashRuntime.getStorage(deps);
 
 		let pluginStates: Map<string, string> = new Map();
-		let siteInfo: { siteName?: string; siteUrl?: string; locale?: string } | undefined;
+		let siteInfo:
+			| {
+					siteName?: string;
+					siteUrl?: string;
+					locale?: string;
+					trailingSlash?: "always" | "never" | "ignore";
+			  }
+			| undefined;
 		// "Already set up" by default so a read failure (e.g. tables absent on a
 		// pre-migration db) skips seeding rather than seeding a half-built db.
 		let seedGate = { collectionCount: 1, setupDone: true };
@@ -1149,6 +1166,10 @@ export class EmDashRuntime {
 				siteName: siteOpts.get("emdash:site_title") ?? undefined,
 				siteUrl: siteOpts.get("emdash:site_url") ?? undefined,
 				locale: siteOpts.get("emdash:locale") ?? undefined,
+				// trailingSlash is a build-time Astro routing decision, not a
+				// user-editable setting, so it comes from the Astro config
+				// (virtual:emdash/config), not the options table.
+				trailingSlash: virtualConfig?.trailingSlash,
 			};
 		};
 
@@ -1831,7 +1852,12 @@ export class EmDashRuntime {
 		deps: RuntimeDependencies,
 		db: Kysely<Database>,
 		mediaStorage?: Storage | null,
-		siteInfo?: { siteName?: string; siteUrl?: string; locale?: string },
+		siteInfo?: {
+			siteName?: string;
+			siteUrl?: string;
+			locale?: string;
+			trailingSlash?: "always" | "never" | "ignore";
+		},
 	): Promise<Map<string, SandboxedPluginInstance>> {
 		// Return cached plugins if already loaded
 		if (sandboxedPluginCache.size > 0) {
@@ -1946,7 +1972,12 @@ export class EmDashRuntime {
 		storage: Storage,
 		deps: RuntimeDependencies,
 		cache: Map<string, SandboxedPluginInstance>,
-		siteInfo?: { siteName?: string; siteUrl?: string; locale?: string },
+		siteInfo?: {
+			siteName?: string;
+			siteUrl?: string;
+			locale?: string;
+			trailingSlash?: "always" | "never" | "ignore";
+		},
 	): Promise<void> {
 		// Ensure sandbox runner exists with media storage wired up.
 		// (storage here is the media Storage adapter from the runtime.)

packages/core/src/plugins/context.ts

@@ -882,6 +882,8 @@ export interface SiteInfoOptions {
 	siteUrl?: string;
 	/** Site locale from options table */
 	locale?: string;
+	/** Astro's `trailingSlash` config (from `virtual:emdash/config`). */
+	trailingSlash?: "always" | "never" | "ignore";
 }
 
 /**
@@ -897,6 +899,7 @@ export function createSiteInfo(options: SiteInfoOptions): SiteInfo {
 		name: options.siteName ?? "",
 		url: (options.siteUrl ?? "").replace(TRAILING_SLASH_RE, ""), // strip trailing slash
 		locale: options.locale ?? "en",
+		trailingSlash: options.trailingSlash ?? "ignore", // Astro's default
 	};
 }
 

packages/core/src/plugins/sandbox/types.ts

@@ -72,7 +72,12 @@ export interface SandboxOptions {
 	/** Default resource limits */
 	limits?: ResourceLimits;
 	/** Site info for plugin context (injected into wrapper at generation time) */
-	siteInfo?: { name: string; url: string; locale: string };
+	siteInfo?: {
+		name: string;
+		url: string;
+		locale: string;
+		trailingSlash?: "always" | "never" | "ignore";
+	};
 	/** Email send callback, wired from the EmailPipeline by the runtime */
 	emailSend?: SandboxEmailSendCallback;
 	/**

packages/core/src/plugins/types.ts

@@ -419,6 +419,14 @@ export interface SiteInfo {
 	url: string;
 	/** Site locale (from settings, defaults to "en") */
 	locale: string;
+	/**
+	 * Astro's `trailingSlash` routing policy, from the host's Astro config.
+	 * Plugins that build absolute URLs (sitemap, canonical, hreflang) should
+	 * honor this so the URLs they emit match what the site serves. `createSiteInfo`
+	 * always populates it (defaulting to `"ignore"`, Astro's default); it is
+	 * optional on the type so pre-existing `SiteInfo` construction stays valid.
+	 */
+	trailingSlash?: "always" | "never" | "ignore";
 }
 
 /**

packages/core/src/virtual-modules.d.ts

@@ -24,6 +24,7 @@ declare module "virtual:emdash/config" {
 		/** Public origin from astro.config.mjs, origin-normalized at startup. */
 		siteUrl?: string;
 		astroCspEnabled?: boolean;
+		trailingSlash?: "always" | "never" | "ignore";
 	}
 
 	const config: VirtualConfig;

packages/core/tests/integration/plugins/capabilities.test.ts

@@ -999,11 +999,13 @@ describe("Capability Enforcement Integration (v2)", () => {
 				siteName: "My Site",
 				siteUrl: "https://example.com/",
 				locale: "fr",
+				trailingSlash: "never",
 			});
 
 			expect(info.name).toBe("My Site");
 			expect(info.url).toBe("https://example.com"); // trailing slash stripped
 			expect(info.locale).toBe("fr");
+			expect(info.trailingSlash).toBe("never");
 		});
 
 		it("uses defaults for missing values", () => {
@@ -1012,6 +1014,7 @@ describe("Capability Enforcement Integration (v2)", () => {
 			expect(info.name).toBe("");
 			expect(info.url).toBe("");
 			expect(info.locale).toBe("en");
+			expect(info.trailingSlash).toBe("ignore"); // Astro's default
 		});
 
 		it("strips trailing slash from URL", () => {

packages/core/tests/integration/runtime/create.test.ts

@@ -150,6 +150,7 @@ describe("EmDashRuntime.create — cold boot", () => {
 						name: "Example Site",
 						url: "https://example.com",
 						locale: "nl",
+						trailingSlash: "ignore",
 					},
 				}),
 			);

packages/core/tests/integration/runtime/plugin-route-site-info.test.ts

@@ -83,6 +83,7 @@ describe("EmDashRuntime.handlePluginApiRoute site context", () => {
 					name: "Example Site",
 					url: "https://example.com",
 					locale: "nl",
+					trailingSlash: "ignore",
 				},
 				url: "https://example.com/checkout/success",
 			},

packages/core/tests/unit/plugins/sandbox-runner-options.test.ts

@@ -20,6 +20,7 @@ describe("createSandboxRunnerOptions", () => {
 				name: "Example Site",
 				url: "https://example.com",
 				locale: "nl",
+				trailingSlash: "ignore",
 			},
 		});
 	});
@@ -33,6 +34,6 @@ describe("createSandboxRunnerOptions", () => {
 
 		expect(options.db).toBe(db);
 		expect(options.mediaStorage).toBe(mediaStorage);
-		expect(options.siteInfo).toEqual({ name: "", url: "", locale: "en" });
+		expect(options.siteInfo).toEqual({ name: "", url: "", locale: "en", trailingSlash: "ignore" });
 	});
 });

packages/workerd/src/sandbox/dev-runner.ts

@@ -51,7 +51,12 @@ const EMDASH_SHIM = "export const definePlugin = (d) => d;\n";
  */
 export class MiniflareDevRunner implements SandboxRunner {
 	private options: SandboxOptions;
-	private siteInfo?: { name: string; url: string; locale: string };
+	private siteInfo?: {
+		name: string;
+		url: string;
+		locale: string;
+		trailingSlash?: "always" | "never" | "ignore";
+	};
 	private emailSendCallback: SandboxEmailSendCallback | null = null;
 
 	/** Miniflare instance (lazily created) */

packages/workerd/src/sandbox/runner.ts

@@ -292,7 +292,12 @@ function isTokenClaims(value: unknown): value is PluginTokenClaims {
 export class WorkerdSandboxRunner implements SandboxRunner {
 	private options: SandboxOptions;
 	private limits: ResolvedLimits;
-	private siteInfo?: { name: string; url: string; locale: string };
+	private siteInfo?: {
+		name: string;
+		url: string;
+		locale: string;
+		trailingSlash?: "always" | "never" | "ignore";
+	};
 
 	/** Loaded plugins indexed by pluginId (manifest.id:manifest.version) */
 	private plugins = new Map<string, LoadedPlugin>();

packages/workerd/src/sandbox/wrapper.ts

@@ -18,7 +18,12 @@ const NEWLINE_RE = /[\n\r]/g;
 const COMMENT_CLOSE_RE = /\*\//g;
 
 export interface WrapperOptions {
-	site?: { name: string; url: string; locale: string };
+	site?: {
+		name: string;
+		url: string;
+		locale: string;
+		trailingSlash?: "always" | "never" | "ignore";
+	};
 	/** URL of the Node backing service (e.g., http://127.0.0.1:18787) */
 	backingServiceUrl: string;
 	/** Auth token the plugin sends on outbound bridge calls to Node */