C++ Parse URL

urlregex.cpp

//sudo apt-get install libboost-all-dev;
//g++ urlregex.cpp -lboost_regex
#include <string>
#include <iostream>
#include <boost/regex.hpp>

using std::string;
using std::cout;
using std::endl;
using std::stringstream;

void parse_url(const string& url) //with boost
{
boost::regex ex("(http|https)://([^/ :]+):?([^/ ]*)(/?[^ #?]*)\\x3f?([^ #]*)#?([^ ]*)");
boost::cmatch what;
if(regex_match(url.c_str(), what, ex))
{
string protocol = string(what[1].first, what[1].second);
string domain = string(what[2].first, what[2].second);
string port = string(what[3].first, what[3].second);
string path = string(what[4].first, what[4].second);
string query = string(what[5].first, what[5].second);
cout << "[" << url << "]" << endl;
cout << protocol << endl;
cout << domain << endl;
cout << port << endl;
cout << path << endl;
cout << query << endl;
cout << "-------------------------------" << endl;
}
}

int main(int argc, char* argv[])
{
parse_url("http://www.google.com");
parse_url("https://mail.google.com/mail/");
parse_url("https://www.google.com:443/webhp?gws_rd=ssl");
return 0;
}

main.cpp (another example, without boost)
#include <string>
#include <iostream>

using std::string;
using std::cout;
using std::endl;
using std::stringstream;

string _trim(const string& str)
{
size_t start = str.find_first_not_of(" \n\r\t");
size_t until = str.find_last_not_of(" \n\r\t");
string::const_iterator i = start==string::npos ? str.begin() : str.begin() + start;
string::const_iterator x = until==string::npos ? str.end() : str.begin() + until+1;
return string(i,x);
}

void parse_url(const string& raw_url) //no boost
{
string path,domain,x,protocol,port,query;
int offset = 0;
size_t pos1,pos2,pos3,pos4;
x = _trim(raw_url);
offset = offset==0 && x.compare(0, 8, "https://")==0 ? 8 : offset;
offset = offset==0 && x.compare(0, 7, "http://" )==0 ? 7 : offset;
pos1 = x.find_first_of('/', offset+1 );
path = pos1==string::npos ? "" : x.substr(pos1);
domain = string( x.begin()+offset, pos1 != string::npos ? x.begin()+pos1 : x.end() );
path = (pos2 = path.find("#"))!=string::npos ? path.substr(0,pos2) : path;
port = (pos3 = domain.find(":"))!=string::npos ? domain.substr(pos3+1) : "";
domain = domain.substr(0, pos3!=string::npos ? pos3 : domain.length());
protocol = offset > 0 ? x.substr(0,offset-3) : "";
query = (pos4 = path.find("?"))!=string::npos ? path.substr(pos4+1) : "";
path = pos4!=string::npos ? path.substr(0,pos4) : path;
cout << "[" << raw_url << "]" << endl;
cout << "protocol: " << protocol << endl;
cout << "domain: " << domain << endl;
cout << "port: " << port << endl;
cout << "path: " << path << endl;
cout << "query: " << query << endl;
}

int main(int argc, char* argv[])
{
parse_url("http://www.google.com");
parse_url("https://mail.google.com/mail/");
parse_url("https://www.google.com:443/webhp?gws_rd=ssl");
return 0;
}

main.cpp (one last example)

#include <string>
#include <stdint.h>
#include <cstring>
#include <sstream>
#include <algorithm>

#include <iostream>
using std::cerr; using std::cout; using std::endl;

using std::string;

class HTTPURL
{
private:
string _protocol;// http vs https
string _domain; // mail.google.com
uint16_t _port; // 80,443
string _path; // /mail/
string _query; // [after ?] a=b&c=b

public:
const string &protocol;
const string &domain;
const uint16_t &port;
const string &path;
const string &query;

HTTPURL(const string& url): protocol(_protocol),domain(_domain),port(_port),path(_path),query(_query)
{
string u = _trim(url);
size_t offset=0, slash_pos, hash_pos, colon_pos, qmark_pos;
string urlpath,urldomain,urlport;
uint16_t default_port;

static const char* allowed[] = { "https://", "http://", "ftp://", NULL};
for(int i=0; allowed[i]!=NULL && this->_protocol.length()==0; i++)
{
const char* c=allowed[i];
if (u.compare(0,strlen(c), c)==0) {
offset = strlen(c);
this->_protocol=string(c,0,offset-3);
}
}
default_port = this->_protocol=="https" ? 443 : 80;
slash_pos = u.find_first_of('/', offset+1 );
urlpath = slash_pos==string::npos ? "/" : u.substr(slash_pos);
urldomain = string( u.begin()+offset, slash_pos != string::npos ? u.begin()+slash_pos : u.end() );
urlpath = (hash_pos = urlpath.find("#"))!=string::npos ? urlpath.substr(0,hash_pos) : urlpath;
urlport = (colon_pos = urldomain.find(":"))!=string::npos ? urldomain.substr(colon_pos+1) : "";
urldomain = urldomain.substr(0, colon_pos!=string::npos ? colon_pos : urldomain.length());
this->_domain = _tolower(urldomain);
this->_query = (qmark_pos = urlpath.find("?"))!=string::npos ? urlpath.substr(qmark_pos+1) : "";
this->_path = qmark_pos!=string::npos ? urlpath.substr(0,qmark_pos) : urlpath;
this->_port = urlport.length()==0 ? default_port : _atoi(urlport) ;
};
private:
static inline string _trim(const string& input)
{
string str = input;
size_t endpos = str.find_last_not_of(" \t\n\r");
if( string::npos != endpos )
{
str = str.substr( 0, endpos+1 );
}
size_t startpos = str.find_first_not_of(" \t\n\r");
if( string::npos != startpos )
{
str = str.substr( startpos );
}
return str;
};
static inline string _tolower(const string& input)
{
string str = input;
std::transform(str.begin(), str.end(), str.begin(), ::tolower);
return str;
};
static inline int _atoi(const string& input)
{
int r;
std::stringstream(input) >> r;
return r;
};
};

int main(int argc, char **argv)
{
HTTPURL u("https://Mail.google.com:80/mail/?action=send#action=send");
cout << "protocol: " << u.protocol << endl;
cout << "domain: " << u.domain << endl;
cout << "port: " << u.port << endl;
cout << "path: " << u.path << endl;
cout << "query: " << u.query << endl;
return 0;
}