multipart.h

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#pragma once
#include "esphome/core/defines.h"
#if defined(USE_ESP32) && defined(USE_WEBSERVER_OTA)
 
#include <cctype>
#include <cstring>
#include <esp_http_server.h>
#include <functional>
#include <multipart_parser.h>
#include <string>
#include <utility>
 
namespace esphome::web_server_idf {
 
// Wrapper around zorxx/multipart-parser for ESP-IDF OTA uploads
class MultipartReader {
 public:
  struct Part {
    std::string name;
    std::string filename;
    std::string content_type;
  };
 
  // IMPORTANT: The data pointer in DataCallback is only valid during the callback!
  // The multipart parser passes pointers to its internal buffer which will be
  // overwritten after the callback returns. Callbacks MUST process or copy the
  // data immediately - storing the pointer for deferred processing will result
  // in use-after-free bugs.
  using DataCallback = std::function<void(const uint8_t *data, size_t len)>;
  using PartCompleteCallback = std::function<void()>;
 
  explicit MultipartReader(const std::string &boundary);
  ~MultipartReader();
 
  // Set callbacks for handling data
  void set_data_callback(DataCallback &&callback) { data_callback_ = std::move(callback); }
  void set_part_complete_callback(PartCompleteCallback &&callback) { part_complete_callback_ = std::move(callback); }
 
  // Parse incoming data
  size_t parse(const char *data, size_t len);
 
  // Get current part info
  const Part &get_current_part() const { return current_part_; }
 
  // Check if we found a file upload
  bool has_file() const { return !current_part_.filename.empty(); }
 
 private:
  static int on_header_field(multipart_parser *parser, const char *at, size_t length);
  static int on_header_value(multipart_parser *parser, const char *at, size_t length);
  static int on_part_data(multipart_parser *parser, const char *at, size_t length);
  static int on_part_data_end(multipart_parser *parser);
 
  multipart_parser *parser_{nullptr};
  multipart_parser_settings settings_{};
 
  Part current_part_;
  std::string current_header_field_;
 
  DataCallback data_callback_;
  PartCompleteCallback part_complete_callback_;
 
  void process_header_(const char *value, size_t length);
};
 
// ========== Utility Functions ==========
 
// Case-insensitive string prefix check
bool str_startswith_case_insensitive(const char *str, size_t str_len, const char *prefix);
 
// Extract a parameter value from a header line
// Handles both quoted and unquoted values
// Assigns to out if found, clears out otherwise
void extract_header_param(const char *header, size_t header_len, const char *param, std::string &out);
 
// Parse boundary from Content-Type header
// Returns true if boundary found, false otherwise
// boundary_start and boundary_len will point to the boundary value
bool parse_multipart_boundary(const char *content_type, const char **boundary_start, size_t *boundary_len);
 
// Trim whitespace from both ends, assign result to out
void str_trim(const char *str, size_t len, std::string &out);
 
}  // namespace esphome::web_server_idf
#endif  // defined(USE_ESP32) && defined(USE_WEBSERVER_OTA)