improv_base.cpp

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#include "improv_base.h"
 
#include <cstring>
#include "esphome/components/network/util.h"
#include "esphome/core/application.h"
#include "esphome/core/defines.h"
#include "esphome/core/log.h"
 
namespace esphome::improv_base {
 
#ifdef USE_IMPROV_NEXT_URL
ESPHOME_LOG_TAG(TAG, "improv_base");
 
static constexpr const char DEVICE_NAME_PLACEHOLDER[] = "{{device_name}}";
static constexpr size_t DEVICE_NAME_PLACEHOLDER_LEN = sizeof(DEVICE_NAME_PLACEHOLDER) - 1;
static constexpr const char IP_ADDRESS_PLACEHOLDER[] = "{{ip_address}}";
static constexpr size_t IP_ADDRESS_PLACEHOLDER_LEN = sizeof(IP_ADDRESS_PLACEHOLDER) - 1;
 
static char *copy_to_buffer(char *dest, const char *end, const char *src) {
  if (src == nullptr) {
    return dest;
  }
  while (*src != '\0' && dest < end) {
    *dest++ = *src++;
  }
  return dest;
}
 
size_t ImprovBase::get_formatted_next_url_(char *buffer, size_t buffer_size) {
  if (this->next_url_ == nullptr || buffer_size == 0) {
    if (buffer_size > 0) {
      buffer[0] = '\0';
    }
    return 0;
  }
 
  // Get IP address once for replacement
  const char *ip_str = nullptr;
  char ip_buffer[network::IP_ADDRESS_BUFFER_SIZE];
  for (auto &ip : network::get_ip_addresses()) {
    if (ip.is_ip4()) {
      ip.str_to(ip_buffer);
      ip_str = ip_buffer;
      break;
    }
  }
 
  const char *device_name = App.get_name().c_str();
  char *out = buffer;
  const char *end = buffer + buffer_size - 1;
 
  // Note: {{esphome_version}} is replaced at code generation time in Python
  for (const char *p = this->next_url_; *p != '\0' && out < end;) {
    if (strncmp(p, DEVICE_NAME_PLACEHOLDER, DEVICE_NAME_PLACEHOLDER_LEN) == 0) {
      out = copy_to_buffer(out, end, device_name);
      p += DEVICE_NAME_PLACEHOLDER_LEN;
    } else if (ip_str != nullptr && strncmp(p, IP_ADDRESS_PLACEHOLDER, IP_ADDRESS_PLACEHOLDER_LEN) == 0) {
      out = copy_to_buffer(out, end, ip_str);
      p += IP_ADDRESS_PLACEHOLDER_LEN;
    } else {
      *out++ = *p++;
    }
  }
  *out = '\0';
  return out - buffer;
}
 
void ImprovBase::add_next_url_(improv::RpcResponseBuilder &builder, size_t max_len) {
  // The builder rejects strings above 254 bytes, so anything longer than this
  // buffer could never be sent anyway
  char url_buffer[256] = {};
  size_t len = this->get_formatted_next_url_(url_buffer, sizeof(url_buffer));
  if (len == 0) {
    return;
  }
  // max_len is the transport's budget for this entry; skipping an over-long URL
  // here keeps the rest of the response sendable instead of oversizing the frame
  if (len > max_len || !builder.add_string(url_buffer, len)) {
    ESP_LOGW(TAG, "Next URL too long; skipping");
  }
}
#endif
 
}  // namespace esphome::improv_base