From efc73c570bb70ba4de23afc785350629ef5016a7 Mon Sep 17 00:00:00 2001
From: cai <cai@nbcai.cc>
Date: Sat, 08 Aug 2026 18:03:18 +0800
Subject: [PATCH] feat: pass bounded ASR ingress metadata

---
 src/asr_realtime.rs |  115 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 110 insertions(+), 5 deletions(-)

diff --git a/src/asr_realtime.rs b/src/asr_realtime.rs
index 16ab4d1..16d2fd3 100644
--- a/src/asr_realtime.rs
+++ b/src/asr_realtime.rs
@@ -1,4 +1,4 @@
-use std::{io, time::Duration};
+use std::{collections::HashMap, io, time::Duration};
 
 use anyhow::{Context, Result, anyhow};
 use base64::{Engine as _, engine::general_purpose};
@@ -28,6 +28,40 @@
     pub(crate) runtime_token: Option<String>,
     pub(crate) runtime_session_nonce: Option<String>,
     pub(crate) chunk_duration_ms: u64,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub(crate) struct AudioIngressMetadata {
+    pub(crate) input_source_category: String,
+    pub(crate) client_fixture_sequence: String,
+}
+
+impl AudioIngressMetadata {
+    pub(crate) fn from_participant(
+        attributes: &HashMap<String, String>,
+    ) -> Result<Option<Self>, &'static str> {
+        let source = attributes.get("inputSourceCategory").map(String::as_str);
+        let sequence = attributes.get("clientFixtureSequence").map(String::as_str);
+        match (source, sequence) {
+            (None, None) => Ok(None),
+            (Some("controlled_fixture"), Some(sequence)) if valid_sequence(sequence) => {
+                Ok(Some(Self {
+                    input_source_category: "controlled_fixture".to_string(),
+                    client_fixture_sequence: sequence.to_string(),
+                }))
+            }
+            (Some(_), _) => Err("invalid_source_or_sequence"),
+            _ => Err("incomplete_metadata"),
+        }
+    }
+}
+
+fn valid_sequence(value: &str) -> bool {
+    !value.is_empty()
+        && value.len() <= 64
+        && value
+            .chars()
+            .all(|ch| ch.is_ascii_alphanumeric() || matches!(ch, '-' | '_' | '.'))
 }
 
 impl RealtimeAsrConfig {
@@ -66,12 +100,13 @@
         trace_id: &str,
         turn_id: &str,
         initial_samples_48k: &[i16],
+        ingress_metadata: Option<&AudioIngressMetadata>,
     ) -> Result<Self> {
         if !config.is_ready() {
             return Err(anyhow!("realtime asr config is not ready"));
         }
         let nonce = config.runtime_session_nonce.as_deref().unwrap_or_default();
-        let session_line = session_start_line(call_id, trace_id, turn_id, nonce)?;
+        let session_line = session_start_line(call_id, trace_id, turn_id, nonce, ingress_metadata)?;
         let (sender, receiver) = mpsc::channel(UPLOAD_QUEUE_CAPACITY);
         let request_call_id = call_id.to_string();
         let request_trace_id = trace_id.to_string();
@@ -295,8 +330,9 @@
     trace_id: &str,
     turn_id: &str,
     runtime_session_nonce: &str,
+    ingress_metadata: Option<&AudioIngressMetadata>,
 ) -> Result<Vec<u8>> {
-    encode_line(json!({
+    let mut line = json!({
         "event": "session_start",
         "callId": call_id,
         "traceId": trace_id,
@@ -307,7 +343,12 @@
             "sampleRate": SAMPLE_RATE_16K,
             "channels": CHANNELS_MONO,
         }
-    }))
+    });
+    if let Some(metadata) = ingress_metadata {
+        line["inputSourceCategory"] = json!(metadata.input_source_category);
+        line["clientFixtureSequence"] = json!(metadata.client_fixture_sequence);
+    }
+    encode_line(line)
 }
 
 fn audio_chunk_line(chunk_seq: u64, samples: &[i16]) -> Result<Vec<u8>> {
@@ -408,7 +449,7 @@
 
     #[test]
     fn session_start_uses_canonical_nonce_hash_and_audio_contract() {
-        let line = session_start_line("call-001", "trace-001", "turn-0001", "nonce-001")
+        let line = session_start_line("call-001", "trace-001", "turn-0001", "nonce-001", None)
             .expect("session start line");
         let value: serde_json::Value = serde_json::from_slice(&line).expect("valid json");
 
@@ -417,6 +458,68 @@
         assert_eq!("pcm_s16le", value["audio"]["format"]);
         assert_eq!(16000, value["audio"]["sampleRate"]);
         assert_eq!(1, value["audio"]["channels"]);
+    }
+
+    #[test]
+    fn participant_attributes_only_metadata_is_bounded_and_frozen() {
+        let mut attributes = HashMap::new();
+        attributes.insert(
+            "inputSourceCategory".to_string(),
+            "controlled_fixture".to_string(),
+        );
+        attributes.insert(
+            "clientFixtureSequence".to_string(),
+            "fixture-01".to_string(),
+        );
+        let metadata =
+            AudioIngressMetadata::from_participant(&attributes).expect("valid attributes");
+        assert_eq!(
+            Some(AudioIngressMetadata {
+                input_source_category: "controlled_fixture".to_string(),
+                client_fixture_sequence: "fixture-01".to_string(),
+            }),
+            metadata
+        );
+
+        attributes.insert(
+            "clientFixtureSequence".to_string(),
+            "bad sequence".to_string(),
+        );
+        assert_eq!(
+            Err("invalid_source_or_sequence"),
+            AudioIngressMetadata::from_participant(&attributes)
+        );
+        assert_eq!(
+            Ok(None),
+            AudioIngressMetadata::from_participant(&HashMap::new())
+        );
+    }
+
+    #[test]
+    fn session_start_omits_absent_attributes_and_emits_bound_attributes() {
+        let bound = AudioIngressMetadata {
+            input_source_category: "controlled_fixture".to_string(),
+            client_fixture_sequence: "fixture-01".to_string(),
+        };
+        let absent = serde_json::from_slice::<serde_json::Value>(
+            &session_start_line("call-001", "trace-001", "turn-0001", "nonce-001", None)
+                .expect("absent session line"),
+        )
+        .expect("absent json");
+        assert!(absent.get("inputSourceCategory").is_none());
+        let with_metadata = serde_json::from_slice::<serde_json::Value>(
+            &session_start_line(
+                "call-001",
+                "trace-001",
+                "turn-0001",
+                "nonce-001",
+                Some(&bound),
+            )
+            .expect("bound session line"),
+        )
+        .expect("bound json");
+        assert_eq!("controlled_fixture", with_metadata["inputSourceCategory"]);
+        assert_eq!("fixture-01", with_metadata["clientFixtureSequence"]);
     }
 
     #[test]
@@ -487,6 +590,7 @@
             "trace-001",
             "turn-0001",
             &vec![1; 9_600],
+            None,
         )
         .expect("start upload");
         upload
@@ -530,6 +634,7 @@
             "trace-002",
             "turn-0002",
             &vec![1; 9_600],
+            None,
         )
         .expect("start upload");
 

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