HTTP compression

/* This file is part of libmicrohttpd Copyright (C) 2019 Christian Grothoff (and other contributing authors) This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file http_compression.c * @brief minimal example for how to compress HTTP response * @author Silvio Clecio (silvioprog) */ #include "platform.h" #include #include #define PAGE \ "HTTP compressionHello, " \ "hello, hello. This is a 'hello world' message for the world, " \ "repeat, for the world." static int can_compress (struct MHD_Connection *con) { const char *ae; const char *de; ae = MHD_lookup_connection_value (con, MHD_HEADER_KIND, MHD_HTTP_HEADER_ACCEPT_ENCODING); if (NULL == ae) return MHD_NO; if (0 == strcmp (ae, "*")) return MHD_YES; de = strstr (ae, "deflate"); if (NULL == de) return MHD_NO; if (((de == ae) || (de[-1] == ',') || (de[-1] == ' ')) && ((de[strlen ("deflate")] == '\0') || (de[strlen ("deflate")] == ',') || (de[strlen ("deflate")] == ';'))) return MHD_YES; return MHD_NO; } static int body_compress (void **buf, size_t *buf_size) { Bytef *cbuf; uLongf cbuf_size; int ret; cbuf_size = compressBound (*buf_size); cbuf = malloc (cbuf_size); if (NULL == cbuf) return MHD_NO; ret = compress (cbuf, &cbuf_size, (const Bytef *) *buf, *buf_size); if ((Z_OK != ret) || (cbuf_size >= *buf_size)) { /* compression failed */ free (cbuf); return MHD_NO; } free (*buf); *buf = (void *) cbuf; *buf_size = (size_t) cbuf_size; return MHD_YES; } static int ahc_echo (void *cls, struct MHD_Connection *connection, const char *url, const char *method, const char *version, const char *upload_data, size_t *upload_data_size, void **ptr) { struct MHD_Response *response; int ret; int comp; size_t body_len; char *body_str; (void) url; /* Unused. Silent compiler warning. */ (void) version; /* Unused. Silent compiler warning. */ (void) upload_data; /* Unused. Silent compiler warning. */ (void) upload_data_size; /* Unused. Silent compiler warning. */ if (0 != strcmp (method, "GET")) return MHD_NO; /* unexpected method */ if (!*ptr) { *ptr = (void *) 1; return MHD_YES; } *ptr = NULL; body_str = strdup (PAGE); if (NULL == body_str) { return MHD_NO; } body_len = strlen (body_str); /* try to compress the body */ comp = MHD_NO; if (MHD_YES == can_compress (connection)) comp = body_compress ((void **) &body_str, &body_len); response = MHD_create_response_from_buffer (body_len, body_str, MHD_RESPMEM_MUST_FREE); if (NULL == response) { free (body_str); return MHD_NO; } if (MHD_YES == comp) { /* Need to indicate to client that body is compressed */ if (MHD_NO == MHD_add_response_header (response, MHD_HTTP_HEADER_CONTENT_ENCODING, "deflate")) { MHD_destroy_response (response); return MHD_NO; } } ret = MHD_queue_response (connection, 200, response); MHD_destroy_response (response); return ret; } int main (int argc, char *const *argv) { struct MHD_Daemon *d; if (argc != 2) { printf ("%s PORT\n", argv[0]); return 1; } d = MHD_start_daemon (MHD_USE_AUTO | MHD_USE_INTERNAL_POLLING_THREAD | MHD_USE_ERROR_LOG, atoi (argv[1]), NULL, NULL, &ahc_echo, NULL, MHD_OPTION_END); if (NULL == d) return 1; (void) getc (stdin); MHD_stop_daemon (d); return 0; }