added URI normalization procedure to opkele::util

as specified in RFC3896, section 6

Signed-off-by: Michael Krelin <hacker@klever.net>

1 files changed, 131 insertions, 0 deletions

diff --git a/lib/util.cc b/lib/util.cc
index 26be66a..eacf6d7 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -1,8 +1,10 @@
 #include <errno.h>
 #include <cassert>
+#include <cctype>
 #include <cstring>
 #include <vector>
 #include <string>
+#include <stack>
 #include <openssl/bio.h>
 #include <openssl/evp.h>
 #include <curl/curl.h>
@@ -159,6 +161,135 @@ namespace opkele {
             return rv;
         }
 
+        /*
+         * Normalize URL according to the rules, described in rfc 3986, section 6
+         *
+         * - uppercase hext triplets (e.g. %ab -> %AB)
+         * - lowercase scheme and host
+         * - decode %-encoded characters, specified as unreserved in rfc 3986, section 2.3,
+         *   that is - [:alpha:][:digit:]._~-
+         * - remove dot segments
+         * - remove empty and default ports
+         * - if there's no path component, add '/'
+         */
+         string rfc_3986_normalize_uri(const string& uri) {
+             string rv;
+             string::size_type colon = uri.find(':');
+             if(colon==string::npos)
+                 throw bad_input(OPKELE_CP_ "No scheme specified in URI");
+             transform(
+                     uri.begin(), uri.begin()+colon+1,
+                     back_inserter(rv), ::tolower );
+             bool s;
+             if(rv=="http:")
+                 s = false;
+             else if(rv=="https:")
+                 s = true;
+             else
+                 throw not_implemented(OPKELE_CP_ "Only http(s) URIs can be normalized here");
+             string::size_type ul = uri.length();
+             if(ul <= (colon+3))
+                 throw bad_input(OPKELE_CP_ "Unexpected end of URI being normalized encountered");
+             if(uri[colon+1]!='/' || uri[colon+2]!='/')
+                 throw bad_input(OPKELE_CP_ "Unexpected input in URI being normalized after scheme component");
+             rv += "//";
+             string::size_type interesting = uri.find_first_of(":/#?",colon+3);
+             if(interesting==string::npos) {
+                 transform(
+                         uri.begin()+colon+3,uri.end(),
+                         back_inserter(rv), ::tolower );
+                 rv += '/'; return rv;
+             }
+             transform(
+                     uri.begin()+colon+3,uri.begin()+interesting,
+                     back_inserter(rv), ::tolower );
+             bool qf = false;
+             char ic = uri[interesting];
+             if(ic==':') {
+                 string::size_type ni = uri.find_first_of("/#?%",interesting+1);
+                 const char *nptr = uri.data()+interesting+1;
+                 char *eptr = 0;
+                 long port = strtol(nptr,&eptr,10);
+                 if( (port>0) && (port<65535) && port!=(s?443:80) ) {
+                     char tmp[6];
+                     snprintf(tmp,sizeof(tmp),"%d",port);
+                     rv += ':'; rv += tmp;
+                 }
+                 if(ni==string::npos) {
+                     rv += '/'; return rv;
+                 }
+                 interesting = ni;
+             }else if(ic!='/') {
+                 rv += '/'; rv += ic;
+                 qf = true;
+                 ++interesting;
+             }
+             string::size_type n = interesting;
+             char tmp[3] = { 0,0,0 };
+             stack<string::size_type> psegs; psegs.push(rv.length());
+             string pseg;
+             for(;n<ul;) {
+                 string::size_type unsafe = uri.find_first_of(qf?"%":"%/?#",n);
+                 if(unsafe==string::npos) {
+                     pseg.append(uri,n,ul-n-1); n = ul-1;
+                 }else{
+                     pseg.append(uri,n,unsafe-n);
+                     n = unsafe;
+                 }
+                 char c = uri[n++];
+                 if(c=='%') {
+                     if((n+1)>=ul)
+                         throw bad_input(OPKELE_CP_ "Unexpected end of URI encountered while parsing percent-encoded character");
+                     tmp[0] = uri[n++];
+                     tmp[1] = uri[n++];
+                     if(!( isxdigit(tmp[0]) && isxdigit(tmp[1]) ))
+                         throw bad_input(OPKELE_CP_ "Invalid percent-encoded character in URI being normalized");
+                     int cc = strtol(tmp,0,16);
+                     if( isalpha(cc) || isdigit(cc) || strchr("._~-",cc) )
+                         pseg += cc;
+                     else{
+                         pseg += '%';
+                         pseg += toupper(tmp[0]); pseg += toupper(tmp[1]);
+                     }
+                 }else if(qf) {
+                     rv += pseg; rv += c;
+                     pseg.clear();
+                 }else if(n>=ul || strchr("?/#",c)) {
+                     if(pseg.empty() || pseg==".") {
+                     }else if(pseg=="..") {
+                         if(psegs.size()>1) {
+                             rv.resize(psegs.top()); psegs.pop();
+                         }
+                     }else{
+                         psegs.push(rv.length());
+                         if(c!='/') {
+                             pseg += c;
+                             qf = true;
+                         }
+                         rv += '/'; rv += pseg;
+                     }
+                     if(c=='/' && (n>=ul || strchr("?#",uri[n])) ) {
+                         rv += '/';
+                         if(n<ul)
+                             qf = true;
+                     }else if(strchr("?#",c)) {
+                         if(psegs.size()==1 && psegs.top()==rv.length())
+                             rv += '/';
+                         if(pseg.empty())
+                             rv += c;
+                         qf = true;
+                     }
+                     pseg.clear();
+                 }else{
+                     pseg += c;
+                 }
+             }
+             if(!pseg.empty()) {
+                 rv += '/'; rv += pseg;
+             }
+             return rv;
+         }
+
     }
 
 }