- websocket client on ESP32

- telemetry protocol builder
- server-side message handling
- database migrations
- telemetry persistence

esp32/main/protocol.cpp

@@ -19,8 +19,59 @@ static inline int append(char* buf, size_t size, int pos, const char* fmt, ...)
     return pos + written;
 }
 
+int build_telemetry(
+    char* buf,
+    size_t buf_size,
+    uint32_t msg_id,
+    int64_t ts,
+    uint32_t device_id,
+    const char* metric,
+    const char* source,
+    const char* unit,
+    const int* values,
+    size_t count
+) {
+    int pos = 0;
+
+    // --- header ---
+    pos = append(buf, buf_size, pos,
+        "{\"v\":1,\"t\":\"t\",\"id\":%lu,\"ts\":%lld,\"d\":%lu,\"p\":{",
+        (unsigned long)msg_id,
+        (long long)ts,
+        (unsigned long)device_id
+    );
+    if (pos < 0) return -1;
+
+    // --- payload meta ---
+    pos = append(buf, buf_size, pos,
+        "\"m\":\"%s\",\"s\":\"%s\",\"u\":\"%s\",\"v\":[",
+        metric,
+        source,
+        unit
+    );
+    if (pos < 0) return -1;
+
+    // --- values ---
+    for (size_t i = 0; i < count; i++) {
+        pos = append(buf, buf_size, pos,
+            "[%u,%d]%s",
+            (unsigned)i,              // delta time (пока просто индекс)
+            values[i],
+            (i < count - 1) ? "," : ""
+        );
+        if (pos < 0) return -1;
+    }
+
+    // --- close ---
+    pos = append(buf, buf_size, pos, "]}}");
+    if (pos < 0) return -1;
+
+    return pos;
+}
+
+__attribute__((deprecated))
 // --- TELEMETRY (single measurement) ---
-int build_telemetry_single(
+    int build_telemetry_single(
     char* buf,
     size_t buf_size,
     const char* id,
@@ -76,6 +127,7 @@ int build_telemetry_single(
     return pos;
 }
 
+__attribute__((deprecated))
 // --- EVENT ---
 int build_event(
     char* buf,