polycubed: fix issue with lists and default elements (#118)

The logic to set default elements in a list was broken as it was trying
to fill the elements as if the list were a container.

This commit reworks the logic to fill default elements, in a list they
are filled only if there are children in the request.

Signed-off-by: Mauricio Vasquez B <mauriciovasquezbernal@gmail.com>

src/polycubed/src/server/Resources/Body/ListResource.cpp

@@ -85,27 +85,6 @@ const Response ListResource::ReadWhole(const std::string &cube_name,
   return ParentResource::ReadValue(cube_name, keys);
 }
 
-void ListResource::SetDefaultIfMissing(nlohmann::json &body) const {
-  // keys default values must be ignored (RFC7950#7.8.2)
-  std::set<std::string> key_names;
-  for (const auto &key : keys_) {
-    key_names.emplace(key.Name());
-  }
-
-  for (const auto &child : children_) {
-    // Set default only for configuration nodes. During initialization
-    // all non-keys can be defaulted, otherwise only the ones that are not
-    // marked as init-only-config.
-    if (key_names.count(child->Name()) == 0 && child->IsConfiguration() &&
-        !child->IsInitOnlyConfig()) {
-      child->SetDefaultIfMissing(body[child->Name()]);
-      if (body[child->Name()].empty()) {
-        body.erase(child->Name());
-      }
-    }
-  }
-}
-
 void ListResource::FillKeys(nlohmann::json &body, const ListKeyValues &keys) {
   // TODO: is there a more efficient implementation of this?
   for (auto &key : keys_) {
@@ -167,9 +146,6 @@ std::vector<Response> ListResource::BodyValidateMultiple(
   }
 
   for (auto &elem : jbody) {
-    if (initialization) {
-      SetDefaultIfMissing(elem);
-    }
     auto body = BodyValidate(cube_name, keys, elem, initialization);
     errors.reserve(errors.size() + body.size());
     std::copy(std::begin(body), std::end(body), std::back_inserter(errors));

src/polycubed/src/server/Resources/Body/ListResource.h

@@ -45,8 +45,6 @@ class ListResource : public virtual ParentResource {
 
   bool IsMandatory() const override;
 
-  void SetDefaultIfMissing(nlohmann::json &body) const final;
-
   /*
    * This function takes the keys (parsed from the url in "keys") and save
    * them in the body of the request

src/polycubed/src/server/Resources/Body/ParentResource.cpp

@@ -157,13 +157,21 @@ bool ParentResource::IsConfiguration() const {
 
 void ParentResource::SetDefaultIfMissing(nlohmann::json &body) const {
   for (const auto &child : children_) {
+    // keys default values must be ignored (RFC7950#7.8.2)
+    if (child->IsKey()) {
+      continue;
+    }
+
     auto &child_body = body[child->Name()];
-    // Lists can't be defaulted. The only possible this is if a list
+    // Lists can't be defaulted. The only possible case is if a list
     // (as json array) is provided in request body. In this situation
     // each element of the array can be defaulted.
     if (std::dynamic_pointer_cast<ListResource>(child) != nullptr) {
-      if (!child_body.empty()) {
+      if (child_body.is_array()) {
         for (auto &entry : child_body) {
+          if (child->IsKey()) {
+            continue;
+          }
           child->SetDefaultIfMissing(entry);
         }
       }