Merge pull request #107 from Magic07/ipv6

Support IPv6 literal address.

Author: melode11

src/internal/sio_client_impl.cpp

@@ -205,13 +205,18 @@ namespace sio
 #else
             ss<<"ws://";
 #endif
-            if (m_sid.size()==0) {
-                ss<<uo.get_host()<<":"<<uo.get_port()<<"/socket.io/?EIO=4&transport=websocket&t="<<time(NULL)<<queryString;
+            const std::string host(uo.get_host());
+            // As per RFC2732, literal IPv6 address should be enclosed in "[" and "]".
+            if(host.find(':')!=std::string::npos){
+                ss<<"["<<uo.get_host()<<"]";
+            } else {
+                ss<<uo.get_host();
             }
-            else
-            {
-                ss<<uo.get_host()<<":"<<uo.get_port()<<"/socket.io/?EIO=4&transport=websocket&sid="<<m_sid<<"&t="<<time(NULL)<<queryString;
+            ss<<":"<<uo.get_port()<<"/socket.io/?EIO=4&transport=websocket";
+            if(m_sid.size()>0){
+                ss<<"&sid="<<m_sid;
             }
+            ss<<"&t="<<time(NULL)<<queryString;
             lib::error_code ec;
             client_type::connection_ptr con = m_client.get_connection(ss.str(), ec);
             if (ec) {