/***************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * $Id$ */ // Get a web page, parse it with libxml. // // Written by Lars Nilsson // // GNU C++ compile command line suggestion (edit paths accordingly): // // g++ -Wall -I/opt/curl/include -I/opt/libxml/include/libxml2 htmltitle.cc \ // -o htmltitle -L/opt/curl/lib -L/opt/libxml/lib -lcurl -lxml2 #include <stdio.h> #include <string.h> #include <stdlib.h> #include <string> #include <curl/curl.h> #include <libxml/HTMLparser.h> // // Case-insensitive string comparison // #ifdef _MSC_VER #define COMPARE(a, b) (!stricmp((a), (b))) #else #define COMPARE(a, b) (!strcasecmp((a), (b))) #endif // // libxml callback context structure // struct Context { Context(): addTitle(false) { } bool addTitle; std::string title; }; // // libcurl variables for error strings and returned data static char errorBuffer[CURL_ERROR_SIZE]; static std::string buffer; // // libcurl write callback function // static int writer(char *data, size_t size, size_t nmemb, std::string *writerData) { if (writerData == NULL) return 0; writerData->append(data, size*nmemb); return size * nmemb; } // // libcurl connection initialization // static bool init(CURL *&conn, char *url) { CURLcode code; conn = curl_easy_init(); if (conn == NULL) { fprintf(stderr, "Failed to create CURL connection\n"); exit(EXIT_FAILURE); } code = curl_easy_setopt(conn, CURLOPT_ERRORBUFFER, errorBuffer); if (code != CURLE_OK) { fprintf(stderr, "Failed to set error buffer [%d]\n", code); return false; } code = curl_easy_setopt(conn, CURLOPT_URL, url); if (code != CURLE_OK) { fprintf(stderr, "Failed to set URL [%s]\n", errorBuffer); return false; } code = curl_easy_setopt(conn, CURLOPT_FOLLOWLOCATION, 1); if (code != CURLE_OK) { fprintf(stderr, "Failed to set redirect option [%s]\n", errorBuffer); return false; } code = curl_easy_setopt(conn, CURLOPT_WRITEFUNCTION, writer); if (code != CURLE_OK) { fprintf(stderr, "Failed to set writer [%s]\n", errorBuffer); return false; } code = curl_easy_setopt(conn, CURLOPT_WRITEDATA, &buffer); if (code != CURLE_OK) { fprintf(stderr, "Failed to set write data [%s]\n", errorBuffer); return false; } return true; } // // libxml start element callback function // static void StartElement(void *voidContext, const xmlChar *name, const xmlChar **attributes) { Context *context = (Context *)voidContext; if (COMPARE((char *)name, "TITLE")) { context->title = ""; context->addTitle = true; } } // // libxml end element callback function // static void EndElement(void *voidContext, const xmlChar *name) { Context *context = (Context *)voidContext; if (COMPARE((char *)name, "TITLE")) context->addTitle = false; } // // Text handling helper function // static void handleCharacters(Context *context, const xmlChar *chars, int length) { if (context->addTitle) context->title.append((char *)chars, length); } // // libxml PCDATA callback function // static void Characters(void *voidContext, const xmlChar *chars, int length) { Context *context = (Context *)voidContext; handleCharacters(context, chars, length); } // // libxml CDATA callback function // static void cdata(void *voidContext, const xmlChar *chars, int length) { Context *context = (Context *)voidContext; handleCharacters(context, chars, length); } // // libxml SAX callback structure // static htmlSAXHandler saxHandler = { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, StartElement, EndElement, NULL, Characters, NULL, NULL, NULL, NULL, NULL, NULL, NULL, cdata, NULL }; // // Parse given (assumed to be) HTML text and return the title // static void parseHtml(const std::string &html, std::string &title) { htmlParserCtxtPtr ctxt; Context context; ctxt = htmlCreatePushParserCtxt(&saxHandler, &context, "", 0, "", XML_CHAR_ENCODING_NONE); htmlParseChunk(ctxt, html.c_str(), html.size(), 0); htmlParseChunk(ctxt, "", 0, 1); htmlFreeParserCtxt(ctxt); title = context.title; } int main(int argc, char *argv[]) { CURL *conn = NULL; CURLcode code; std::string title; // Ensure one argument is given if (argc != 2) { fprintf(stderr, "Usage: %s <url>\n", argv[0]); exit(EXIT_FAILURE); } curl_global_init(CURL_GLOBAL_DEFAULT); // Initialize CURL connection if (!init(conn, argv[1])) { fprintf(stderr, "Connection initializion failed\n"); exit(EXIT_FAILURE); } // Retrieve content for the URL code = curl_easy_perform(conn); curl_easy_cleanup(conn); if (code != CURLE_OK) { fprintf(stderr, "Failed to get '%s' [%s]\n", argv[1], errorBuffer); exit(EXIT_FAILURE); } // Parse the (assumed) HTML code parseHtml(buffer, title); // Display the extracted title printf("Title: %s\n", title.c_str()); return EXIT_SUCCESS; }