Files
wget2/examples/print_html_urls.c
Tim Rühsen 483c304aef Support parsing of UTF-16 HTML documents
* examples/print_html_urls.c (html_parse_localfile):
  Detect BOM (Byte Order Mark), convert UTF-16 to UTF-8 before parsing.
* include/libwget.h.in: Remove wget_charset_transcode(),
  add wget_memiconv() and wget_striconv().
* libwget/encoding.c: Implement wget_memiconv() and wget_striconv()
* src/wget.c (html_parse): Add 'html_len' param,
  convert UTF-16 to UTF-8 before parsing.
* tests/test.c: New test for wget_memiconv().
2016-04-24 15:08:20 +02:00

132 lines
3.4 KiB
C

/*
* Copyright(c) 2013 Tim Ruehsen
* Copyright(c) 2015-2016 Free Software Foundation, Inc.
*
* This file is part of libwget.
*
* Libwget 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 3 of the License, or
* (at your option) any later version.
*
* Libwget 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 libwget. If not, see <http://www.gnu.org/licenses/>.
*
*
* Example for HTML parsing using libwget
*
* Changelog
* 03.01.2014 Tim Ruehsen created
*
* Demonstrate how to extract URIs from HTML files using callback functions.
* We don't care about character encoding in this example.
*
*/
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <unistd.h>
#include <libwget.h>
static void html_parse_localfile(const char *fname)
{
char *data;
const char *encoding = NULL;
size_t len;
if ((data = wget_read_file(fname, &len))) {
if ((unsigned char)data[0] == 0xFE && (unsigned char)data[1] == 0xFF) {
// Big-endian UTF-16
encoding = "UTF-16BE";
// adjust behind BOM, ignore trailing single byte
data += 2;
len -= 2;
} else if ((unsigned char)data[0] == 0xFF && (unsigned char)data[1] == 0xFE) {
// Little-endian UTF-16
encoding = "UTF-16LE";
// adjust behind BOM
data += 2;
len -= 2;
} else if ((unsigned char)data[0] == 0xEF && (unsigned char)data[1] == 0xBB && (unsigned char)data[2] == 0xBF) {
// UTF-8
encoding = "UTF-8";
// adjust behind BOM
data += 3;
len -= 3;
}
if (encoding)
printf("URI encoding '%s' set by BOM\n", encoding);
if (!wget_strncasecmp_ascii(encoding, "UTF-16", 6)) {
size_t n;
char *utf8;
len -= len & 1; // ignore single trailing byte, else charset conversion fails
if (wget_memiconv(encoding, data, len, "UTF-8", &utf8, &n) == 0) {
printf("Convert non-ASCII encoding '%s' to UTF-8\n", encoding);
data = utf8;
} else {
printf("Failed to convert non-ASCII encoding '%s' to UTF-8, skip parsing\n", encoding);
return;
}
}
WGET_HTML_PARSED_RESULT *res = wget_html_get_urls_inline(data, NULL, NULL);
if (encoding) {
if (res->encoding && wget_strcasecmp_ascii(encoding, res->encoding))
printf("Encoding '%s' as stated in document has been ignored\n", encoding);
}
for (int it = 0; it < wget_vector_size(res->uris); it++) {
WGET_HTML_PARSED_URL *html_url = wget_vector_get(res->uris, it);
wget_string_t *url = &html_url->url;
printf(" %s.%s '%.*s'\n", html_url->dir, html_url->attr, (int) url->len, url->p);
}
wget_xfree(data);
wget_html_free_urls_inline(&res);
}
}
int main(int argc, const char *const *argv)
{
/*
wget_global_init(
WGET_DEBUG_STREAM, stderr,
WGET_ERROR_STREAM, stderr,
WGET_INFO_STREAM, stdout,
NULL);
*/
if (!isatty(STDIN_FILENO)) {
// read HTML data from STDIN
html_parse_localfile("-");
} else {
// parse CSS files given as arguments
int argpos;
for (argpos = 1; argpos < argc; argpos++) {
printf("%s:\n", argv[argpos]);
// use '-' as filename for STDIN
html_parse_localfile(argv[argpos]);
}
}
return 0;
}