Add client-side bidder support for Prebid.js

crates/common/src/integrations/prebid.rs

@@ -69,6 +69,18 @@ pub struct PrebidIntegrationConfig {
         deserialize_with = "crate::settings::vec_from_seq_or_map"
     )]
     pub script_patterns: Vec<String>,
+    /// Bidders that should run client-side in the browser via native Prebid.js
+    /// adapters instead of being routed through the server-side auction.
+    ///
+    /// These bidders are **not** absorbed into the `trustedServer` adapter and
+    /// remain as standalone bids in each ad unit.  The corresponding Prebid.js
+    /// adapter modules must be statically imported in the JS bundle so they are
+    /// available at runtime.
+    ///
+    /// This list is independent of [`bidders`](Self::bidders) — the operator
+    /// manages both lists explicitly.
+    #[serde(default, deserialize_with = "crate::settings::vec_from_seq_or_map")]
+    pub client_side_bidders: Vec<String>,
     /// Per-bidder, per-zone param overrides. The outer key is a bidder name, the
     /// inner key is a zone name (sent by the JS adapter from `mediaTypes.banner.name`
     /// — a non-standard Prebid.js field used as a temporary workaround),
@@ -218,6 +230,20 @@ fn build(settings: &Settings) -> Option<Arc<PrebidIntegration>> {
         log::warn!("Prebid integration disabled: prebid.server_url missing");
         return None;
     }
+
+    // Warn about bidders that appear in both lists — this is likely a config
+    // mistake. A bidder should be in either `bidders` (server-side) or
+    // `client_side_bidders` (browser-side), not both.
+    for bidder in &config.client_side_bidders {
+        if config.bidders.iter().any(|b| b == bidder) {
+            log::warn!(
+                "prebid: bidder \"{}\" is in both bidders and client_side_bidders — \
+                 it will run server-side AND be left for client-side, which is likely unintended",
+                bidder
+            );
+        }
+    }
+
     Some(PrebidIntegration::new(config))
 }
 
@@ -306,13 +332,16 @@ impl IntegrationHeadInjector for PrebidIntegration {
             timeout: u32,
             debug: bool,
             bidders: &'a [String],
+            #[serde(skip_serializing_if = "<[String]>::is_empty")]
+            client_side_bidders: &'a [String],
         }
 
         let payload = InjectedPrebidClientConfig {
             account_id: self.config.account_id.as_deref().unwrap_or_default(),
             timeout: self.config.timeout_ms,
             debug: self.config.debug,
             bidders: &self.config.bidders,
+            client_side_bidders: &self.config.client_side_bidders,
         };
 
         // Escape `</` to prevent breaking out of the script tag.
@@ -1022,6 +1051,7 @@ mod tests {
             test_mode: false,
             debug_query_params: None,
             script_patterns: default_script_patterns(),
+            client_side_bidders: Vec::new(),
             bid_param_zone_overrides: HashMap::new(),
         }
     }
@@ -1477,6 +1507,48 @@ server_url = "https://prebid.example"
         );
     }
 
+    #[test]
+    fn head_injector_omits_client_side_bidders_when_empty() {
+        let integration = PrebidIntegration::new(base_config());
+        let document_state = IntegrationDocumentState::default();
+        let ctx = IntegrationHtmlContext {
+            request_host: "pub.example",
+            request_scheme: "https",
+            origin_host: "origin.example",
+            document_state: &document_state,
+        };
+
+        let inserts = integration.head_inserts(&ctx);
+        let script = &inserts[0];
+        assert!(
+            !script.contains("clientSideBidders"),
+            "should omit clientSideBidders when empty: {}",
+            script
+        );
+    }
+
+    #[test]
+    fn head_injector_includes_client_side_bidders_when_configured() {
+        let mut config = base_config();
+        config.client_side_bidders = vec!["rubicon".to_string(), "magnite".to_string()];
+        let integration = PrebidIntegration::new(config);
+        let document_state = IntegrationDocumentState::default();
+        let ctx = IntegrationHtmlContext {
+            request_host: "pub.example",
+            request_scheme: "https",
+            origin_host: "origin.example",
+            document_state: &document_state,
+        };
+
+        let inserts = integration.head_inserts(&ctx);
+        let script = &inserts[0];
+        assert!(
+            script.contains(r#""clientSideBidders":["rubicon","magnite"]"#),
+            "should include clientSideBidders array: {}",
+            script
+        );
+    }
+
     #[test]
     fn to_openrtb_includes_debug_flags_when_enabled() {
         let mut config = base_config();

crates/js/lib/build-all.mjs

@@ -7,6 +7,12 @@
  * Output (in ../dist/):
  *   tsjs-core.js          — core API (always included)
  *   tsjs-<integration>.js — one per discovered integration
+ *
+ * Environment variables:
+ *   TSJS_PREBID_ADAPTERS — Comma-separated list of Prebid.js bid adapter
+ *     names to include in the bundle (e.g. "rubicon,appnexus,openx").
+ *     Each name must have a corresponding {name}BidAdapter.js module in
+ *     the prebid.js package. Default: "rubicon".
  */
 
 import fs from 'node:fs';
@@ -19,6 +25,90 @@ const srcDir = path.resolve(__dirname, 'src');
 const distDir = path.resolve(__dirname, '..', 'dist');
 const integrationsDir = path.join(srcDir, 'integrations');
 
+// ---------------------------------------------------------------------------
+// Prebid adapter generation
+// ---------------------------------------------------------------------------
+
+const DEFAULT_PREBID_ADAPTERS = 'rubicon';
+const ADAPTERS_FILE = path.join(
+  integrationsDir,
+  'prebid',
+  '_adapters.generated.ts',
+);
+
+/**
+ * Generate `_adapters.generated.ts` with import statements for each adapter
+ * listed in the TSJS_PREBID_ADAPTERS environment variable.
+ *
+ * Invalid adapter names (those without a matching module in prebid.js) are
+ * logged and skipped.
+ */
+function generatePrebidAdapters() {
+  const raw = process.env.TSJS_PREBID_ADAPTERS || DEFAULT_PREBID_ADAPTERS;
+  const names = raw
+    .split(',')
+    .map((s) => s.trim())
+    .filter(Boolean);
+
+  if (names.length === 0) {
+    console.warn(
+      '[build-all] TSJS_PREBID_ADAPTERS is empty, falling back to default:',
+      DEFAULT_PREBID_ADAPTERS,
+    );
+    names.push(DEFAULT_PREBID_ADAPTERS);
+  }
+
+  const modulesDir = path.join(
+    __dirname,
+    'node_modules',
+    'prebid.js',
+    'modules',
+  );
+
+  // Validate each adapter and build import lines
+  const imports = [];
+  for (const name of names) {
+    const moduleFile = `${name}BidAdapter.js`;
+    const modulePath = path.join(modulesDir, moduleFile);
+    if (!fs.existsSync(modulePath)) {
+      console.error(
+        `[build-all] WARNING: Prebid adapter "${name}" not found (expected ${moduleFile}), skipping`,
+      );
+      continue;
+    }
+    imports.push(`import 'prebid.js/modules/${moduleFile}';`);
+  }
+
+  if (imports.length === 0) {
+    console.error(
+      '[build-all] WARNING: No valid Prebid adapters found, bundle will have no client-side adapters',
+    );
+  }
+
+  const content = [
+    '// Auto-generated by build-all.mjs — manual edits will be overwritten at build time.',
+    '//',
+    '// Controls which Prebid.js bid adapters are included in the bundle.',
+    '// Set the TSJS_PREBID_ADAPTERS environment variable to a comma-separated list',
+    '// of adapter names (e.g. "rubicon,appnexus,openx") before building.',
+    `// Default: "${DEFAULT_PREBID_ADAPTERS}"`,
+    '',
+    ...imports,
+    '',
+  ].join('\n');
+
+  fs.writeFileSync(ADAPTERS_FILE, content);
+
+  const adapterNames = names.filter((name) =>
+    fs.existsSync(path.join(modulesDir, `${name}BidAdapter.js`)),
+  );
+  console.log('[build-all] Prebid adapters:', adapterNames);
+}
+
+generatePrebidAdapters();
+
+// ---------------------------------------------------------------------------
+
 // Clean dist directory
 fs.rmSync(distDir, { recursive: true, force: true });
 fs.mkdirSync(distDir, { recursive: true });
@@ -47,6 +137,16 @@ async function buildModule(name, entryPath) {
   await build({
     configFile: false,
     root: __dirname,
+    resolve: {
+      alias: {
+        // prebid.js doesn't expose src/adapterManager.js via its package
+        // "exports" map, but we need it for client-side bidder validation.
+        'prebid.js/src/adapterManager.js': path.resolve(
+          __dirname,
+          'node_modules/prebid.js/dist/src/src/adapterManager.js',
+        ),
+      },
+    },
     build: {
       emptyOutDir: false,
       outDir: distDir,

crates/js/lib/src/integrations/prebid/_adapters.generated.ts

@@ -0,0 +1,8 @@
+// Auto-generated by build-all.mjs — manual edits will be overwritten at build time.
+//
+// Controls which Prebid.js bid adapters are included in the bundle.
+// Set the TSJS_PREBID_ADAPTERS environment variable to a comma-separated list
+// of adapter names (e.g. "rubicon,appnexus,openx") before building.
+// Default: "rubicon"
+
+import 'prebid.js/modules/rubiconBidAdapter.js';