JSON: support basic legacy path

src/commands/cmd_json.cc

@@ -25,6 +25,9 @@
 
 namespace redis {
 
+///
+/// JSON.SET <key> <path> <json>
+///
 class CommandJsonSet : public Commander {
  public:
   Status Execute(Server *svr, Connection *conn, std::string *output) override {
@@ -52,7 +55,7 @@ class CommandJsonGet : public Commander {
   }
 };
 
-REDIS_REGISTER_COMMANDS(MakeCmdAttr<CommandJsonSet>("json.set", -3, "write", 1, 1, 1),
+REDIS_REGISTER_COMMANDS(MakeCmdAttr<CommandJsonSet>("json.set", 3, "write", 1, 1, 1),
                         MakeCmdAttr<CommandJsonGet>("json.get", -2, "read-only", 1, 1, 1), );
 
 }  // namespace redis

src/types/json.h

@@ -83,3 +83,13 @@ struct JsonValue {
 
   jsoncons::json value;
 };
+
+// https://redis.io/docs/data-types/json/path/#legacy-path-syntax
+inline std::optional<std::string_view> tryConvertLegacyToJsonPath(std::string_view path) {
+  // TODO(mwish): currently I only handling the simplest logic,
+  //  port from RedisJson JsonPathParser::parse later.
+  if (path == ".") {
+    return "$";
+  }
+  return std::nullopt;
+}

src/types/redis_json.cc

@@ -52,8 +52,13 @@ rocksdb::Status Json::Set(const std::string &user_key, const std::string &path,
   Slice rest;
   auto s = GetMetadata(kRedisJson, ns_key, &bytes, &metadata, &rest);
 
+  std::string_view real_path = path;
+  if (auto legacy_path = tryConvertLegacyToJsonPath(path); legacy_path.has_value()) {
+    real_path = legacy_path.value();
+  }
+
   if (s.IsNotFound()) {
-    if (path != "$") return rocksdb::Status::InvalidArgument("new objects must be created at the root");
+    if (real_path != "$") return rocksdb::Status::InvalidArgument("new objects must be created at the root");
 
     auto json_res = JsonValue::FromString(value);
     if (!json_res) return rocksdb::Status::InvalidArgument(json_res.Msg());
@@ -75,7 +80,7 @@ rocksdb::Status Json::Set(const std::string &user_key, const std::string &path,
   if (!origin_res) return rocksdb::Status::Corruption(origin_res.Msg());
   auto origin = *std::move(origin_res);
 
-  auto set_res = origin.Set(path, std::move(new_val));
+  auto set_res = origin.Set(real_path, std::move(new_val));
   if (!set_res) return rocksdb::Status::InvalidArgument(set_res.Msg());
 
   return write(ns_key, &metadata, origin);
@@ -102,14 +107,22 @@ rocksdb::Status Json::Get(const std::string &user_key, const std::vector<std::st
   if (paths.empty()) {
     res = std::move(json_val);
   } else if (paths.size() == 1) {
-    auto get_res = json_val.Get(paths[0]);
+    std::string_view real_path = paths[0];
+    if (auto legacy_path = tryConvertLegacyToJsonPath(paths[0]); legacy_path.has_value()) {
+      real_path = legacy_path.value();
+    }
+    auto get_res = json_val.Get(real_path);
     if (!get_res) return rocksdb::Status::InvalidArgument(get_res.Msg());
     res = *std::move(get_res);
   } else {
     for (const auto &path : paths) {
-      auto get_res = json_val.Get(path);
+      std::string_view real_path = path;
+      if (auto legacy_path = tryConvertLegacyToJsonPath(paths[0]); legacy_path.has_value()) {
+        real_path = legacy_path.value();
+      }
+      auto get_res = json_val.Get(real_path);
       if (!get_res) return rocksdb::Status::InvalidArgument(get_res.Msg());
-      res.value.insert_or_assign(path, std::move(get_res->value));
+      res.value.insert_or_assign(real_path, std::move(get_res->value));
     }
   }
 

tests/cppunit/types/json_test.cc

@@ -119,3 +119,21 @@ TEST_F(RedisJsonTest, Get) {
   ASSERT_TRUE(json_->Get(key_, {"$..x", "$..y", "$..z"}, &json_val_).ok());
   ASSERT_EQ(json_val_.Dump(), R"({"$..x":[{"y":1},4],"$..y":[[2,{"z":3}],1],"$..z":[{"a":{"x":4}},3]})");
 }
+
+TEST_F(RedisJsonTest, LegacyPath) {
+  ASSERT_THAT(json_->Set(key_, ".", "invalid").ToString(), MatchesRegex(".*syntax_error.*"));
+  ASSERT_THAT(json_->Set(key_, ".", "{").ToString(), MatchesRegex(".*Unexpected end of file.*"));
+
+  ASSERT_TRUE(json_->Set(key_, ".", "  \t{\n  }  ").ok());
+  ASSERT_TRUE(json_->Get(key_, {"."}, &json_val_).ok());
+  ASSERT_EQ(json_val_.Dump(), "[{}]");
+
+  auto s = json_->Set(key_, ".", "1");
+  ASSERT_TRUE(s.ok()) << s.ToString();
+  ASSERT_TRUE(json_->Get(key_, {"."}, &json_val_).ok());
+  ASSERT_EQ(json_val_.Dump(), "[1]");
+
+  ASSERT_TRUE(json_->Set(key_, ".", "[1, 2, 3]").ok());
+  ASSERT_TRUE(json_->Get(key_, {"."}, &json_val_).ok());
+  ASSERT_EQ(json_val_.Dump(), "[[1,2,3]]");
+}