mongoose/docs/c-api/http.h/mg_get_http_header.md

title	decl_name	symbol_kind	signature
mg_get_http_header()	mg_get_http_header	func	struct mg_str *mg_get_http_header(struct http_message *hm, const char *name);

Search and return header name in parsed HTTP message hm. If header is not found, NULL is returned. Example:

struct mg_str *host_hdr = mg_get_http_header(hm, "Host");