Use XML-sanitized strings when serializing stanzas for the XMPP server

src/test.cpp

@@ -97,6 +97,14 @@ int main()
       });
   xml.feed(doc.data(), doc.size(), true);
 
+  const std::string doc2 = "<stream xmlns='s'><stanza>coucou\r\n\a</stanza></stream>";
+  xml.add_stanza_callback([](const Stanza& stanza)
+      {
+        std::cout << stanza.to_string() << std::endl;
+        assert(stanza.get_inner() == "coucou\r\n");
+      });
+  xml.feed(doc2.data(), doc.size(), true);
+
   /**
    * XML escape/escape
    */

src/xmpp/xmpp_stanza.cpp

@@ -192,12 +192,13 @@ std::string XmlNode::to_string() const
   std::string res("<");
   res += this->name;
   for (const auto& it: this->attributes)
-    res += " " + it.first + "='" + it.second + "'";
+    res += " " + utils::remove_invalid_xml_chars(it.first) + "='" +
+      utils::remove_invalid_xml_chars(it.second) + "'";
   if (this->closed && !this->has_children() && this->inner.empty())
     res += "/>";
   else
     {
-      res += ">" + this->inner;
+      res += ">" + utils::remove_invalid_xml_chars(this->inner);
       for (const auto& child: this->children)
         res += child->to_string();
       if (this->closed)
@@ -205,7 +206,7 @@ std::string XmlNode::to_string() const
           res += "</" + this->name + ">";
         }
     }
-  res += this->tail;
+  res += utils::remove_invalid_xml_chars(this->tail);
   return res;
 }