web_server_idf: support x-www-form-urlencoded POST requests (#6037)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/components/web_server_idf/utils.cpp

@@ -0,0 +1,93 @@
+#ifdef USE_ESP_IDF
+#include <memory>
+#include "esphome/core/log.h"
+#include "esphome/core/helpers.h"
+#include "http_parser.h"
+
+#include "utils.h"
+
+namespace esphome {
+namespace web_server_idf {
+
+static const char *const TAG = "web_server_idf_utils";
+
+void url_decode(char *str) {
+  char *ptr = str, buf;
+  for (; *str; str++, ptr++) {
+    if (*str == '%') {
+      str++;
+      if (parse_hex(str, 2, reinterpret_cast<uint8_t *>(&buf), 1) == 2) {
+        *ptr = buf;
+        str++;
+      } else {
+        str--;
+        *ptr = *str;
+      }
+    } else if (*str == '+') {
+      *ptr = ' ';
+    } else {
+      *ptr = *str;
+    }
+  }
+  *ptr = *str;
+}
+
+bool request_has_header(httpd_req_t *req, const char *name) { return httpd_req_get_hdr_value_len(req, name); }
+
+optional<std::string> request_get_header(httpd_req_t *req, const char *name) {
+  size_t len = httpd_req_get_hdr_value_len(req, name);
+  if (len == 0) {
+    return {};
+  }
+
+  std::string str;
+  str.resize(len);
+
+  auto res = httpd_req_get_hdr_value_str(req, name, &str[0], len + 1);
+  if (res != ESP_OK) {
+    return {};
+  }
+
+  return {str};
+}
+
+optional<std::string> request_get_url_query(httpd_req_t *req) {
+  auto len = httpd_req_get_url_query_len(req);
+  if (len == 0) {
+    return {};
+  }
+
+  std::string str;
+  str.resize(len);
+
+  auto res = httpd_req_get_url_query_str(req, &str[0], len + 1);
+  if (res != ESP_OK) {
+    ESP_LOGW(TAG, "Can't get query for request: %s", esp_err_to_name(res));
+    return {};
+  }
+
+  return {str};
+}
+
+optional<std::string> query_key_value(const std::string &query_url, const std::string &key) {
+  if (query_url.empty()) {
+    return {};
+  }
+
+  auto val = std::unique_ptr<char[]>(new char[query_url.size()]);
+  if (!val) {
+    ESP_LOGE(TAG, "Not enough memory to the query key value");
+    return {};
+  }
+
+  if (httpd_query_key_value(query_url.c_str(), key.c_str(), val.get(), query_url.size()) != ESP_OK) {
+    return {};
+  }
+
+  url_decode(val.get());
+  return {val.get()};
+}
+
+}  // namespace web_server_idf
+}  // namespace esphome
+#endif  // USE_ESP_IDF