added util::attr_escape

escaping string for inclusion into x(ht)ml attributes

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

2 files changed, 26 insertions, 0 deletions

diff --git a/include/opkele/util.h b/include/opkele/util.h
index 6f3ddf6..719f951 100644
--- a/include/opkele/util.h
+++ b/include/opkele/util.h
@@ -79,48 +79,55 @@ namespace opkele {
 	/**
 	 * Convert internal time representation to w3c format
 	 * @param t internal representation
 	 * @return w3c time
 	 * @throw failed_conversion in case of error
 	 */
 	string time_to_w3c(time_t t);
 	/**
 	 * Convert W3C time representation to  internal time_t
 	 * @param w w3c representation
 	 * @return converted time
 	 * @throw failed_conversion in case of error
 	 */
 	time_t w3c_to_time(const string& w);
 
 	/**
 	 * Encode string to the representation suitable for using in URL.
 	 * @param str string to encode
 	 * @return encoded string
 	 * @throw failed_conversion in case of failure
 	 */
 	string url_encode(const string& str);
 
 	/**
+	 * Make string suitable for using as x(ht)ml attribute.
+	 * @param str string to escape
+	 * @return escaped string
+	 */
+	string attr_escape(const string& str);
+
+	/**
 	 * Convert number to string
 	 * @param l number
 	 * @return string representation
 	 * @throw failed_conversion in case of failure
 	 */
 	string long_to_string(long l);
 	/**
 	 * Convert string to number
 	 * @param s string, containing the number
 	 * @return the number
 	 * @throw failed_conversion in case of failure
 	 */
 	long string_to_long(const string& s);
 
 	/**
 	 * Encode binary data using base64.
 	 * @param data pointer to binary data
 	 * @param length length of data
 	 * @return encoded data
 	 */
 	string encode_base64(const void *data,size_t length);
 	/**
 	 * Decode binary data from base64 representation.
 	 * @param data base64-encoded data
diff --git a/lib/util.cc b/lib/util.cc
index 54d6535..b7bc437 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -140,48 +140,67 @@ namespace opkele {
 			) != 7
 		    ) )
 		throw failed_conversion(OPKELE_CP_ "failed to sscanf()");
 	    tm_t.tm_mon--;
 	    tm_t.tm_year-=1900;
 	    time_t rv = mktime(&tm_t);
 	    if(rv==(time_t)-1)
 		throw failed_conversion(OPKELE_CP_ "failed to mktime()");
 	    return rv-timezone;
 	}
 
 	/*
 	 *
 	 */
 
 	string url_encode(const string& str) {
 	    char * t = curl_escape(str.c_str(),str.length());
 	    if(!t)
 		throw failed_conversion(OPKELE_CP_ "failed to curl_escape()");
 	    string rv(t);
 	    curl_free(t);
 	    return rv;
 	}
 
+	string attr_escape(const string& str) {
+	    static const char *unsafechars = "<>&\n\"'";
+	    string rv;
+	    string::size_type p=0;
+	    while(true) {
+		string::size_type us = str.find_first_of(unsafechars,p);
+		if(us==string::npos) {
+		    if(p!=str.length())
+			rv.append(str,p,str.length()-p);
+		    return rv;
+		}
+		rv.append(str,p,us-p);
+		rv += "&#";
+		rv += long_to_string((long)str[us]);
+		rv += ';';
+		p = us+1;
+	    }
+	}
+
 	string long_to_string(long l) {
 	    char rv[32];
 	    int r=snprintf(rv,sizeof(rv),"%ld",l);
 	    if(r<0 || r>=(int)sizeof(rv))
 		throw failed_conversion(OPKELE_CP_ "failed to snprintf()");
 	    return rv;
 	}
 
 	long string_to_long(const string& s) {
 	    char *endptr = 0;
 	    long rv = strtol(s.c_str(),&endptr,10);
 	    if((!endptr) || endptr==s.c_str())
 		throw failed_conversion(OPKELE_CP_ "failed to strtol()");
 	    return rv;
 	}
 
 	/*
 	 * Normalize URL according to the rules, described in rfc 3986, section 6
 	 *
 	 * - uppercase hex 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