From 76a6c39f25f187d9b9209c857df2c6a5881d761e Mon Sep 17 00:00:00 2001
From: Anthony Uk <1492471+dataway@users.noreply.github.com>
Date: Thu, 8 Apr 2021 14:21:42 +0200
Subject: [PATCH] mqtt_client: Added MQTTClientComponent::unsubscribe() (#1672)

Co-authored-by: Otto Winter <otto@otto-winter.com>
---
 esphome/components/mqtt/mqtt_client.cpp | 20 ++++++++++++++++++++
 esphome/components/mqtt/mqtt_client.h   |  9 +++++++++
 2 files changed, 29 insertions(+)

diff --git a/esphome/components/mqtt/mqtt_client.cpp b/esphome/components/mqtt/mqtt_client.cpp
index 2eb1c52153..190df0b2f3 100644
--- a/esphome/components/mqtt/mqtt_client.cpp
+++ b/esphome/components/mqtt/mqtt_client.cpp
@@ -347,6 +347,26 @@ void MQTTClientComponent::subscribe_json(const std::string &topic, mqtt_json_cal
   this->subscriptions_.push_back(subscription);
 }
 
+void MQTTClientComponent::unsubscribe(const std::string &topic) {
+  uint16_t ret = this->mqtt_client_.unsubscribe(topic.c_str());
+  yield();
+  if (ret != 0) {
+    ESP_LOGV(TAG, "unsubscribe(topic='%s')", topic.c_str());
+  } else {
+    delay(5);
+    ESP_LOGV(TAG, "Unsubscribe failed for topic='%s'.", topic.c_str());
+    this->status_momentary_warning("unsubscribe", 1000);
+  }
+
+  auto it = subscriptions_.begin();
+  while (it != subscriptions_.end()) {
+    if (it->topic == topic)
+      it = subscriptions_.erase(it);
+    else
+      ++it;
+  }
+}
+
 // Publish
 bool MQTTClientComponent::publish(const std::string &topic, const std::string &payload, uint8_t qos, bool retain) {
   return this->publish(topic, payload.data(), payload.size(), qos, retain);
diff --git a/esphome/components/mqtt/mqtt_client.h b/esphome/components/mqtt/mqtt_client.h
index 2bbebff845..885f4a9a96 100644
--- a/esphome/components/mqtt/mqtt_client.h
+++ b/esphome/components/mqtt/mqtt_client.h
@@ -159,6 +159,15 @@ class MQTTClientComponent : public Component {
    */
   void subscribe_json(const std::string &topic, mqtt_json_callback_t callback, uint8_t qos = 0);
 
+  /** Unsubscribe from an MQTT topic.
+   *
+   * If multiple existing subscriptions to the same topic exist, all of them will be removed.
+   *
+   * @param topic The topic to unsubscribe from.
+   * Must match the topic in the original subscribe or subscribe_json call exactly.
+   */
+  void unsubscribe(const std::string &topic);
+
   /** Publish a MQTTMessage
    *
    * @param message The message.