Handle percent encoding of URL and request parameters. Resolves fhessel#19

Author: fhessel

src/ResourceResolver.cpp

@@ -58,8 +58,7 @@ void ResourceResolver::resolveNode(const std::string &method, const std::string
       std::string name  = param.substr(0, nvSplitIdx);
       std::string value = "";
       if (nvSplitIdx != std::string::npos) {
-        // TODO: There may be url encoding in here.
-        value = param.substr(nvSplitIdx+1);
+        value = urlDecode(param.substr(nvSplitIdx+1));
       }
 
       // Now we finally have name and value.
@@ -116,15 +115,15 @@ void ResourceResolver::resolveNode(const std::string &method, const std::string
               // Second step: Grab the parameter value
               if (nodeIdx == nodepath.length()) {
                 // Easy case: parse until end of string
-                params->setUrlParameter(pIdx, resourceName.substr(urlIdx));
+                params->setUrlParameter(pIdx, urlDecode(resourceName.substr(urlIdx)));
               } else {
                 // parse until first char after the placeholder
                 char terminatorChar = nodepath[nodeIdx];
                 size_t terminatorPosition = resourceName.find(terminatorChar, urlIdx);
                 if (terminatorPosition != std::string::npos) {
                   // We actually found the terminator
                   size_t dynamicLength = terminatorPosition-urlIdx;
-                  params->setUrlParameter(pIdx, resourceName.substr(urlIdx, dynamicLength));
+                  params->setUrlParameter(pIdx, urlDecode(resourceName.substr(urlIdx, dynamicLength)));
                   urlIdx = urlIdx + dynamicLength;
                 } else {
                   // We did not find the terminator

src/util.cpp

@@ -58,3 +58,34 @@ std::string intToString(int i) {
 }
 
 }
+
+std::string urlDecode(std::string input) {
+  std::size_t idxReplaced = 0;
+  std::size_t idxFound = input.find('%');
+  while (idxFound != std::string::npos) {
+    if (idxFound <= input.length() + 3) {
+      char hex[2] = { input[idxFound+1], input[idxFound+2] };
+      byte val = 0;
+      for(int n = 0; n < sizeof(hex); n++) {
+        val <<= 4;
+        if ('0' <= hex[n] && hex[n] <= '9') {
+          val += hex[n]-'0';
+        }
+        else if ('A' <= hex[n] && hex[n] <= 'F') {
+          val += hex[n]-'A'+10;
+        }
+        else if ('a' <= hex[n] && hex[n] <= 'f') {
+          val += hex[n]-'a'+10;
+        }
+        else {
+          goto skipChar;
+        }
+      }
+      input.replace(idxFound, 3, 1, (char)val);
+    }
+    skipChar:
+    idxReplaced = idxFound + 1;
+    idxFound = input.find('%', idxReplaced);
+  }
+  return input;
+}

src/util.hpp

@@ -27,4 +27,9 @@ std::string intToString(int i);
 
 }
 
+/**
+ * \brief **Utility function**: Removes URL encoding from the string (e.g. %20 -> space)
+ */
+std::string urlDecode(std::string input);
+
 #endif /* SRC_UTIL_HPP_ */