297 lines
6.3 KiB
C++
297 lines
6.3 KiB
C++
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/***************************************************************************
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* _ _ ____ _
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* Project ___| | | | _ \| |
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* / __| | | | |_) | |
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* | (__| |_| | _ <| |___
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* \___|\___/|_| \_\_____|
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*
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* Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
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*
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* This software is licensed as described in the file COPYING, which
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* you should have received as part of this distribution. The terms
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* are also available at https://curl.se/docs/copyright.html.
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*
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* You may opt to use, copy, modify, merge, publish, distribute and/or sell
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* copies of the Software, and permit persons to whom the Software is
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* furnished to do so, under the terms of the COPYING file.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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* SPDX-License-Identifier: curl
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*
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***************************************************************************/
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/* <DESC>
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* Get a web page, extract the title with libxml.
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* </DESC>
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Written by Lars Nilsson
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GNU C++ compile command line suggestion (edit paths accordingly):
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g++ -Wall -I/opt/curl/include -I/opt/libxml/include/libxml2 htmltitle.cpp \
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-o htmltitle -L/opt/curl/lib -L/opt/libxml/lib -lcurl -lxml2
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*/
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <string>
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#include <curl/curl.h>
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#include <libxml/HTMLparser.h>
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//
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// Case-insensitive string comparison
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//
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#ifdef _MSC_VER
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#define COMPARE(a, b) (!_stricmp((a), (b)))
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#else
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#define COMPARE(a, b) (!strcasecmp((a), (b)))
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#endif
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//
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// libxml callback context structure
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//
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struct Context
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{
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Context(): addTitle(false) { }
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bool addTitle;
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std::string title;
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};
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//
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// libcurl variables for error strings and returned data
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static char errorBuffer[CURL_ERROR_SIZE];
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static std::string buffer;
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//
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// libcurl write callback function
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//
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static int writer(char *data, size_t size, size_t nmemb,
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std::string *writerData)
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{
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if(writerData == NULL)
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return 0;
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writerData->append(data, size*nmemb);
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return size * nmemb;
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}
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//
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// libcurl connection initialization
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//
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static bool init(CURL *&conn, char *url)
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{
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CURLcode code;
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conn = curl_easy_init();
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if(conn == NULL) {
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fprintf(stderr, "Failed to create CURL connection\n");
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exit(EXIT_FAILURE);
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}
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code = curl_easy_setopt(conn, CURLOPT_ERRORBUFFER, errorBuffer);
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if(code != CURLE_OK) {
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fprintf(stderr, "Failed to set error buffer [%d]\n", code);
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return false;
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}
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code = curl_easy_setopt(conn, CURLOPT_URL, url);
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if(code != CURLE_OK) {
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fprintf(stderr, "Failed to set URL [%s]\n", errorBuffer);
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return false;
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}
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code = curl_easy_setopt(conn, CURLOPT_FOLLOWLOCATION, 1L);
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if(code != CURLE_OK) {
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fprintf(stderr, "Failed to set redirect option [%s]\n", errorBuffer);
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return false;
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}
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code = curl_easy_setopt(conn, CURLOPT_WRITEFUNCTION, writer);
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if(code != CURLE_OK) {
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fprintf(stderr, "Failed to set writer [%s]\n", errorBuffer);
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return false;
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}
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code = curl_easy_setopt(conn, CURLOPT_WRITEDATA, &buffer);
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if(code != CURLE_OK) {
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fprintf(stderr, "Failed to set write data [%s]\n", errorBuffer);
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return false;
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}
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return true;
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}
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//
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// libxml start element callback function
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//
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static void StartElement(void *voidContext,
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const xmlChar *name,
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const xmlChar **attributes)
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{
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Context *context = static_cast<Context *>(voidContext);
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if(COMPARE(reinterpret_cast<char *>(name), "TITLE")) {
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context->title = "";
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context->addTitle = true;
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}
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(void) attributes;
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}
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//
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// libxml end element callback function
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//
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static void EndElement(void *voidContext,
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const xmlChar *name)
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{
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Context *context = static_cast<Context *>(voidContext);
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if(COMPARE(reinterpret_cast<char *>(name), "TITLE"))
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context->addTitle = false;
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}
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//
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// Text handling helper function
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//
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static void handleCharacters(Context *context,
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const xmlChar *chars,
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int length)
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{
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if(context->addTitle)
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context->title.append(reinterpret_cast<char *>(chars), length);
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}
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//
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// libxml PCDATA callback function
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//
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static void Characters(void *voidContext,
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const xmlChar *chars,
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int length)
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{
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Context *context = static_cast<Context *>(voidContext);
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handleCharacters(context, chars, length);
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}
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//
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// libxml CDATA callback function
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//
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static void cdata(void *voidContext,
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const xmlChar *chars,
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int length)
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{
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Context *context = static_cast<Context *>(voidContext);
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handleCharacters(context, chars, length);
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}
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//
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// libxml SAX callback structure
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//
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static htmlSAXHandler saxHandler =
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{
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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StartElement,
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EndElement,
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NULL,
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Characters,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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cdata,
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NULL
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};
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//
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// Parse given (assumed to be) HTML text and return the title
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//
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static void parseHtml(const std::string &html,
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std::string &title)
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{
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htmlParserCtxtPtr ctxt;
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Context context;
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ctxt = htmlCreatePushParserCtxt(&saxHandler, &context, "", 0, "",
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XML_CHAR_ENCODING_NONE);
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htmlParseChunk(ctxt, html.c_str(), html.size(), 0);
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htmlParseChunk(ctxt, "", 0, 1);
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htmlFreeParserCtxt(ctxt);
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title = context.title;
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}
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int main(int argc, char *argv[])
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{
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CURL *conn = NULL;
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CURLcode code;
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std::string title;
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// Ensure one argument is given
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if(argc != 2) {
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fprintf(stderr, "Usage: %s <url>\n", argv[0]);
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exit(EXIT_FAILURE);
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}
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curl_global_init(CURL_GLOBAL_DEFAULT);
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// Initialize CURL connection
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if(!init(conn, argv[1])) {
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fprintf(stderr, "Connection initialization failed\n");
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exit(EXIT_FAILURE);
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}
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// Retrieve content for the URL
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code = curl_easy_perform(conn);
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curl_easy_cleanup(conn);
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if(code != CURLE_OK) {
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fprintf(stderr, "Failed to get '%s' [%s]\n", argv[1], errorBuffer);
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exit(EXIT_FAILURE);
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}
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// Parse the (assumed) HTML code
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parseHtml(buffer, title);
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// Display the extracted title
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printf("Title: %s\n", title.c_str());
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return EXIT_SUCCESS;
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}
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