[text] Add text_sensor for read-only view of text component (#15090)

esphome/components/text/text_sensor/__init__.py

@@ -0,0 +1,25 @@
+import esphome.codegen as cg
+from esphome.components import text_sensor
+import esphome.config_validation as cv
+from esphome.const import CONF_SOURCE_ID
+
+from .. import Text, text_ns
+
+TextTextSensor = text_ns.class_("TextTextSensor", text_sensor.TextSensor, cg.Component)
+
+
+CONFIG_SCHEMA = (
+    text_sensor.text_sensor_schema(TextTextSensor)
+    .extend(
+        {
+            cv.Required(CONF_SOURCE_ID): cv.use_id(Text),
+        }
+    )
+    .extend(cv.COMPONENT_SCHEMA)
+)
+
+
+async def to_code(config):
+    source = await cg.get_variable(config[CONF_SOURCE_ID])
+    var = await text_sensor.new_text_sensor(config, source)
+    await cg.register_component(var, config)

esphome/components/text/text_sensor/text_text_sensor.cpp

@@ -0,0 +1,16 @@
+#include "text_text_sensor.h"
+#include "esphome/core/log.h"
+
+namespace esphome::text {
+
+static const char *const TAG = "text.text_sensor";
+
+void TextTextSensor::setup() {
+  this->source_->add_on_state_callback([this](const std::string &value) { this->publish_state(value); });
+  if (this->source_->has_state())
+    this->publish_state(this->source_->state);
+}
+
+void TextTextSensor::dump_config() { LOG_TEXT_SENSOR("", "Text Text Sensor", this); }
+
+}  // namespace esphome::text

esphome/components/text/text_sensor/text_text_sensor.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "../text.h"
+#include "esphome/core/component.h"
+#include "esphome/components/text_sensor/text_sensor.h"
+
+namespace esphome::text {
+
+class TextTextSensor : public text_sensor::TextSensor, public Component {
+ public:
+  explicit TextTextSensor(Text *source) : source_(source) {}
+  void setup() override;
+  void dump_config() override;
+
+ protected:
+  Text *source_;
+};
+
+}  // namespace esphome::text

tests/components/text/common.yaml

@@ -23,3 +23,8 @@ text:
     min_length: 8
     max_length: 32
     mode: password
+
+text_sensor:
+  - platform: text
+    name: "Test Text State"
+    source_id: test_text