Solution

/***************************************************************
** Name:        url.h
** Author:      Leo Liberti
** Source:      GNU C++
** Purpose:     www exploring topologizer - URL data type (header)
** History:     060820 work started
****************************************************************/

#ifndef _WETURLH
#define _WETURLH

#include<string>
#include "htmlpage.h"

class URLException {
 public:
  URLException();
  ~URLException();
};

class URL {
 public:

  URL();
  URL(std::string theURL);
  ~URL();

  std::string getURLName(void) const;
  void setURLName(std::string theURL);
  std::string getFileName(void) const;
  
  // download the URL
  void download(void) throw(URLException);
  
  // return the HTTP links in the URL
  std::string getNextLink(void) throw(URLException);

  // return the hostname in the URL
  std::string getHostName(void);

 private:
  HTMLPage* htmlPagePtr;
  std::string URLName;
  std::string fileName;
  int linkCounter;

};

#endif

/***************************************************************
** Name:        url.cxx
** Author:      Leo Liberti
** Source:      GNU C++
** Purpose:     www exploring topologizer - URL data type 
** History:     060820 work started
****************************************************************/

#include<iostream>
#include<string>
#include<cstdlib>
#include<algorithm>
#include<unistd.h>
#include "url.h"
#include "wet.h"

namespace WET {
  const char charSlash = '/';
  const char charQuote = '\"';
  const std::string protocolTag = "http://";
  const std::string theCommand = "wget --timeout=10 --quiet -O ";
  const std::string stdFileName = ".wet.html";
};

URLException::URLException() { }
URLException::~URLException() { }

URL::URL() : htmlPagePtr(NULL), linkCounter(0) { }

URL::URL(std::string theURL) : 
  URLName(theURL), htmlPagePtr(NULL), linkCounter(0) { }

URL::~URL() { 
  if (htmlPagePtr) {
    delete htmlPagePtr;
#ifdef DEBUG
    std::cerr << "** destroying URL " << this 
              << " and htmlPagePtr " << htmlPagePtr << std::endl; 
  } else {
    std::cerr << "** destroying URL " << this << std::endl; 
#endif
  }
}

std::string URL::getURLName(void) const {
  return URLName;
}

void URL::setURLName(std::string theURL) {
  URLName = theURL;
}

std::string URL::getFileName(void) const {
  return fileName;
}

void URL::download(void) throw(URLException) {
  using namespace std;
  using namespace WET;
  if (URLName == "") {
    cerr << "URL::download(): URLName not initialized" << endl;
    throw URLException();
  }
  unlink(stdFileName.c_str());
  string cmd = theCommand + stdFileName + " " + 
    charQuote + URLName + charQuote;
  // spawn the command
#ifdef DEBUG
  cerr << "** URL: exec " << cmd << endl;
#endif
  int status = system(cmd.c_str());
  // create the HTML page
  htmlPagePtr = new HTMLPage(stdFileName, URLName);
  // delete the filename now
  unlink(stdFileName.c_str());
}

std::string URL::getNextLink(void) throw(URLException) {
  using namespace std;
  if (!htmlPagePtr) {
    cerr << "URL::getNextLink(): uninitialized htmlPagePtr" << endl;
    throw URLException();
  }
  string ret;
  if (linkCounter == htmlPagePtr->getNumberOfLinks()) {
    linkCounter = 0;
    return ret;
  }
  ret = htmlPagePtr->getLink(linkCounter);
  linkCounter++;
  return ret;
}

std::string URL::getHostName(void) {
  using namespace std;
  string::size_type p = URLName.find(WET::protocolTag);
  string::size_type from, to, length;
  if (p == URLName.npos) {
    // not found
    from = 0;
  } else {
    from = WET::protocolTag.size();
  }
  to = URLName.find(WET::charSlash, from);
  if (to == URLName.npos) {
    length = URLName.size();
  } else {
    length = to - from;
  }
  string ret = URLName.substr(from, length);
  return ret;
}