KARadioProtocol DRAFT

Author: pschatzmann

examples/sandbox/ka-radio-protocol-server/KA-Radio-Protocol.h

@@ -0,0 +1,173 @@
+#pragma once
+
+#include <optional>
+
+#include "AudioTools/CoreAudio/AudioBasic/Str.h"
+#include "AudioTools/CoreAudio/AudioPlayer.h"
+#include "AudioTools/Disk/AudioSource.h"
+
+#define KA_VERSION "Release: 2.4, Revision: R0"
+
+namespace audio_tools {
+
+/***
+ * @brief KA-Radio Protocol: We can use the KA-Radio protocol to control the
+ * audio player provided by the audiotools. Example: volume=50&play=128&infos
+ * See https://github.com/karawin/Ka-Radio32/blob/master/Interface.md
+ * @author Phil Schatzmann
+ */
+
+class KARadioProtocol {
+ public:
+  /// Default constructor
+  KARadioProtocol(AudioPlayer& player) { setPlayer(player); }
+
+  /// Empty constructor: call setPlayer to define the player
+  KARadioProtocol() = default;
+
+  /// Defines the player
+  void setPlayer(AudioPlayer& player) {
+    p_player = &player;
+    volume = player.volume() * 254.0f;
+  }
+
+  /// processes the commands and returns the result output via the Print object
+  bool processCommand(const char* input, Print& result) {
+    if (p_player == nullptr) {
+      LOGE("player not set");
+      return false;
+    }
+
+    Str name;
+    Str arg;
+    StrView line = input;
+
+    int start = line.indexOf('?');
+    if (start < 0) start = 0;
+    int endPos = line.length();
+    bool rc = true;
+    while (start >= 0 && start < endPos) {
+      int eqPos = line.indexOf('=', start);
+      int toPos = getEndPos(line, start + 1);
+      if (eqPos >= 0) {
+        name.substring(line, start + 1, eqPos);
+        arg.substring(line, eqPos + 1, toPos);
+      } else {
+        name.substring(line, start + 1, toPos);
+        arg = "";
+      }
+      LOGD("start=%d, eqPos=%d, toPos=%d", start, eqPos, toPos);
+      // remove leading and trailing spaces
+      name.trim();
+      arg.trim();
+      // execute the command
+      rc = processCommand(name, arg, result);
+      // calculate new positions
+      start = toPos;
+      toPos = getEndPos(line, start + 1);
+    }
+    return rc;
+  }
+
+  /// Processes a single command
+  bool processCommand(Str& name, Str& arg, Print& result) {
+    LOGI("command: %s (%s)", name.c_str(), arg.c_str());
+    if (p_player == nullptr) {
+      LOGE("No player set");
+      return false;
+    }
+    if (name == "play") {
+      if (!arg.isEmpty()) {
+        int idx = arg.toInt();
+        p_player->setIndex(idx);
+      }
+    } else if (name == "instant") {
+      p_player->setPath(arg.c_str());
+    } else if (name == "volume") {
+      if (!arg.isEmpty()) {
+        volume = arg.toInt();
+        p_player->setVolume(static_cast<float>(volume) / 254.0f);
+      }
+    } else if (name == "volume+") {
+      volume += 5;
+      if (volume > 245) {
+        volume = 254;
+      }
+      p_player->setVolume(static_cast<float>(volume) / 254.0f);
+    } else if (name == "volume-") {
+      volume -= 5;
+      if (volume < 0) {
+        volume = 0;
+      }
+      p_player->setVolume(static_cast<float>(volume) / 254.0f);
+    } else if (name == "pause") {
+      p_player->setActive(false);
+    } else if (name == "resume") {
+      p_player->setActive(true);
+    } else if (name == "stop") {
+      p_player->setActive(false);
+    } else if (name == "start") {
+      p_player->setActive(true);
+    } else if (name == "next") {
+      p_player->next();
+    } else if (name == "prev") {
+      p_player->previous();
+    } else if (name == "version") {
+      result.print("version: ");
+      result.println(KA_VERSION);
+    } else if (name == "mute") {
+      if (!arg.isEmpty()) {
+        p_player->setActive(!(arg.toInt() == 1));
+      }
+    } else if (name == "infos") {
+      result.print("vol: ");
+      result.println(volume);
+      result.print("num: ");
+      result.println(index());
+      result.print("stn: ");  // station
+      result.println(stationName());
+      result.print("tit: ");  // title
+      result.println(title());
+      result.print("sts: ");  // status
+      result.println(p_player->isActive());
+    } else if (name == "list") {
+      // arg: 0 to 254
+      if (!arg.isEmpty()) {
+        p_player->setIndex(arg.toInt());
+      }
+      result.println(stationName());
+    } else {
+      LOGE("Invalid command:", name.c_str());
+      return false;
+    }
+    result.flush();
+    return true;
+  }
+
+  /// Provides the actual index
+  int index() { return p_player->audioSource().index(); }
+
+  /// Provides the actual title
+  const char* title() { return title_str.c_str(); }
+
+ protected:
+  AudioPlayer* p_player = nullptr;
+  int volume = 0;
+  Str title_str = "n/a";
+
+  int getEndPos(StrView& line, int start) {
+    int endPos = line.indexOf('&', start);
+    if (endPos < 0) {
+      endPos = line.length();
+    }
+    return endPos;
+  }
+
+  const char* stationName() {
+    if (p_player != nullptr) {
+      return p_player->audioSource().toStr();
+    }
+    return "";
+  }
+};
+}  // namespace audio_tools