better error msg on live view when misconfigured

Improves (but doesn't fix) #119 and #120.

CHANGELOG.md

@@ -14,7 +14,8 @@ Each release is tagged in Git and on the Docker repository
     workaround, so anamorphic videos looked correct on Chrome but slightly
     stretched on Firefox. Now both live streams and playback are fully correct
     on all browsers.
-*   UI: better error message on browsers where live view is unsupported.
+*   UI: better error messages on live view when browser is unsupported,
+    `sub` stream is unconfigured, or `sub` stream is not set to record.
 *   upgrade to retina v0.1.0, which uses `SET_PARAMETERS` rather than
     `GET_PARAMETERS` as a RTSP keepalive. GW Security cameras would ignored
     the latter, causing Moonfire NVR to drop the connection every minute.

design/api.md

@@ -177,6 +177,7 @@ Example response:
           "maxEndTime90k": 130985466591817,
           "totalDuration90k": 96736169725,
           "totalSampleFileBytes": 446774393937,
+          "record": true,
           "days": {
             "2016-05-01": {
               "endTime90k": 131595516000000,

guide/troubleshooting.md

@@ -399,9 +399,6 @@ here are some things to check:
     guide](schema.md) prior to 29 Feb 2020, look at [this
     update](https://github.com/scottlamb/moonfire-nvr/commit/92266612b5c9163eb6096c580ba751280a403648#diff-e8bdd96dda101a25a541a6629675ea46bd6eaf670c6417c76662db5397c50c19)
     to those instructions.
-*   The live view currently only uses the `sub` stream. If you configure only
-    a `main` stream on your cameras, you will see this error consistently.
-    [#119](https://github.com/scottlamb/moonfire-nvr/issues/119)
 
 ### Errors in kernel logs
 

server/src/json.rs

@@ -83,6 +83,7 @@ pub struct Stream<'a> {
     pub total_duration_90k: Duration,
     pub total_sample_file_bytes: i64,
     pub fs_bytes: i64,
+    pub record: bool,
 
     #[serde(skip_serializing_if = "Option::is_none")]
     #[serde(serialize_with = "Stream::serialize_days")]
@@ -243,6 +244,7 @@ impl<'a> Stream<'a> {
             total_duration_90k: s.duration,
             total_sample_file_bytes: s.sample_file_bytes,
             fs_bytes: s.fs_bytes,
+            record: s.record,
             days: if include_days { Some(s.days()) } else { None },
             config: match include_config {
                 false => None,

ui/src/Live/LiveCamera.tsx

@@ -80,6 +80,15 @@ class LiveCameraDriver {
     if (this.ws !== undefined) {
       return;
     }
+    const subStream = this.camera.streams.sub;
+    if (subStream === undefined || !subStream.record) {
+      this.error(
+        "Must have sub stream set to record; see " +
+          "https://github.com/scottlamb/moonfire-nvr/issues/119 and " +
+          "https://github.com/scottlamb/moonfire-nvr/issues/120"
+      );
+      return;
+    }
     console.log(`${this.camera.shortName}: starting stream: ${reason}`);
     const loc = window.location;
     const proto = loc.protocol === "https:" ? "wss" : "ws";

ui/src/types.ts

@@ -31,6 +31,7 @@ export interface Stream {
   totalSampleFileBytes: number;
   fsBytes: number;
   days: Record<string, Day>;
+  record: boolean;
 }
 
 export interface Day {