esphome/esphome/components/esp32_camera_web_server/camera_web_server.cpp

#ifdef USE_ESP32

#include "camera_web_server.h"
#include "esphome/core/application.h"
#include "esphome/core/hal.h"
#include "esphome/core/helpers.h"
#include "esphome/core/log.h"
#include "esphome/core/util.h"

#include <cstdlib>
#include <esp_http_server.h>
#include <utility>

namespace esphome {
namespace esp32_camera_web_server {

static const int IMAGE_REQUEST_TIMEOUT = 2000;
static const char *const TAG = "esp32_camera_web_server";

#define PART_BOUNDARY "123456789000000000000987654321"
#define CONTENT_TYPE "image/jpeg"
#define CONTENT_LENGTH "Content-Length"

static const char *const STREAM_HEADER =
    "HTTP/1.1 200\r\nAccess-Control-Allow-Origin: *\r\nContent-Type: multipart/x-mixed-replace;boundary=" PART_BOUNDARY
    "\r\n";
static const char *const STREAM_500 = "HTTP/1.1 500\r\nContent-Type: text/plain\r\n\r\nNo frames send.\r\n";
static const char *const STREAM_BOUNDARY = "\r\n--" PART_BOUNDARY "\r\n";
static const char *const STREAM_PART = "Content-Type: " CONTENT_TYPE "\r\n" CONTENT_LENGTH ": %u\r\n\r\n";

CameraWebServer::CameraWebServer() {}

CameraWebServer::~CameraWebServer() {}

void CameraWebServer::setup() {
  if (!esp32_camera::global_esp32_camera || esp32_camera::global_esp32_camera->is_failed()) {
    this->mark_failed();
    return;
  }

  this->semaphore_ = xSemaphoreCreateBinary();

  httpd_config_t config = HTTPD_DEFAULT_CONFIG();
  config.server_port = this->port_;
  config.ctrl_port = this->port_;
  config.max_open_sockets = 1;
  config.backlog_conn = 2;

  if (httpd_start(&this->httpd_, &config) != ESP_OK) {
    mark_failed();
    return;
  }

  httpd_uri_t uri = {
      .uri = "/",
      .method = HTTP_GET,
      .handler = [](struct httpd_req *req) { return ((CameraWebServer *) req->user_ctx)->handler_(req); },
      .user_ctx = this};

  httpd_register_uri_handler(this->httpd_, &uri);

  esp32_camera::global_esp32_camera->add_image_callback([this](std::shared_ptr<esp32_camera::CameraImage> image) {
    if (this->running_) {
      this->image_ = std::move(image);
      xSemaphoreGive(this->semaphore_);
    }
  });
}

void CameraWebServer::on_shutdown() {
  this->running_ = false;
  this->image_ = nullptr;
  httpd_stop(this->httpd_);
  this->httpd_ = nullptr;
  vSemaphoreDelete(this->semaphore_);
  this->semaphore_ = nullptr;
}

void CameraWebServer::dump_config() {
  ESP_LOGCONFIG(TAG, "ESP32 Camera Web Server:");
  ESP_LOGCONFIG(TAG, "  Port: %d", this->port_);
  if (this->mode_ == STREAM)
    ESP_LOGCONFIG(TAG, "  Mode: stream");
  else
    ESP_LOGCONFIG(TAG, "  Mode: snapshot");

  if (this->is_failed()) {
    ESP_LOGE(TAG, "  Setup Failed");
  }
}

float CameraWebServer::get_setup_priority() const { return setup_priority::LATE; }

void CameraWebServer::loop() {
  if (!this->running_) {
    this->image_ = nullptr;
  }
}

std::shared_ptr<esphome::esp32_camera::CameraImage> CameraWebServer::wait_for_image_() {
  std::shared_ptr<esphome::esp32_camera::CameraImage> image;
  image.swap(this->image_);

  if (!image) {
    // retry as we might still be fetching image
    xSemaphoreTake(this->semaphore_, IMAGE_REQUEST_TIMEOUT / portTICK_PERIOD_MS);
    image.swap(this->image_);
  }

  return image;
}

esp_err_t CameraWebServer::handler_(struct httpd_req *req) {
  esp_err_t res = ESP_FAIL;

  this->image_ = nullptr;
  this->running_ = true;

  switch (this->mode_) {
    case STREAM:
      res = this->streaming_handler_(req);
      break;

    case SNAPSHOT:
      res = this->snapshot_handler_(req);
      break;
  }

  this->running_ = false;
  this->image_ = nullptr;
  return res;
}

static esp_err_t httpd_send_all(httpd_req_t *r, const char *buf, size_t buf_len) {
  int ret;

  while (buf_len > 0) {
    ret = httpd_send(r, buf, buf_len);
    if (ret < 0) {
      return ESP_FAIL;
    }
    buf += ret;
    buf_len -= ret;
  }
  return ESP_OK;
}

esp_err_t CameraWebServer::streaming_handler_(struct httpd_req *req) {
  esp_err_t res = ESP_OK;
  char part_buf[64];

  // This manually constructs HTTP response to avoid chunked encoding
  // which is not supported by some clients

  res = httpd_send_all(req, STREAM_HEADER, strlen(STREAM_HEADER));
  if (res != ESP_OK) {
    ESP_LOGW(TAG, "STREAM: failed to set HTTP header");
    return res;
  }

  uint32_t last_frame = millis();
  uint32_t frames = 0;

  while (res == ESP_OK && this->running_) {
    if (esp32_camera::global_esp32_camera != nullptr) {
      esp32_camera::global_esp32_camera->request_stream();
    }

    auto image = this->wait_for_image_();

    if (!image) {
      ESP_LOGW(TAG, "STREAM: failed to acquire frame");
      res = ESP_FAIL;
    }
    if (res == ESP_OK) {
      res = httpd_send_all(req, STREAM_BOUNDARY, strlen(STREAM_BOUNDARY));
    }
    if (res == ESP_OK) {
      size_t hlen = snprintf(part_buf, 64, STREAM_PART, image->get_data_length());
      res = httpd_send_all(req, part_buf, hlen);
    }
    if (res == ESP_OK) {
      res = httpd_send_all(req, (const char *) image->get_data_buffer(), image->get_data_length());
    }
    if (res == ESP_OK) {
      frames++;
      int64_t frame_time = millis() - last_frame;
      last_frame = millis();

      ESP_LOGD(TAG, "MJPG: %uB %ums (%.1ffps)", (uint32_t) image->get_data_length(), (uint32_t) frame_time,
               1000.0 / (uint32_t) frame_time);
    }
  }

  if (!frames) {
    res = httpd_send_all(req, STREAM_500, strlen(STREAM_500));
  }

  ESP_LOGI(TAG, "STREAM: closed. Frames: %u", frames);

  return res;
}

esp_err_t CameraWebServer::snapshot_handler_(struct httpd_req *req) {
  esp_err_t res = ESP_OK;

  if (esp32_camera::global_esp32_camera != nullptr) {
    esp32_camera::global_esp32_camera->request_image();
  }

  auto image = this->wait_for_image_();

  if (!image) {
    ESP_LOGW(TAG, "SNAPSHOT: failed to acquire frame");
    httpd_resp_send_500(req);
    res = ESP_FAIL;
    return res;
  }

  res = httpd_resp_set_type(req, CONTENT_TYPE);
  if (res != ESP_OK) {
    ESP_LOGW(TAG, "SNAPSHOT: failed to set HTTP response type");
    return res;
  }

  httpd_resp_set_hdr(req, "Content-Disposition", "inline; filename=capture.jpg");

  if (res == ESP_OK) {
    res = httpd_resp_set_hdr(req, CONTENT_LENGTH, esphome::to_string(image->get_data_length()).c_str());
  }
  if (res == ESP_OK) {
    res = httpd_resp_send(req, (const char *) image->get_data_buffer(), image->get_data_length());
  }
  return res;
}

}  // namespace esp32_camera_web_server
}  // namespace esphome

#endif  // USE_ESP32