Sensor nodes in ubiquitous sensor network (USN) environments are composed of many sensors and hardware components for various purposes and applications, such as service in the industrial field, the public administration sector, and in life services. A middleware is required for wireless sensors to treat a huge amount of information from sensor nodes. However, the use of a middleware and specialized application services could be a big obstacle for the portability of heterogeneous hardware, software platforms, and various methods of information consumption. These problems can be solved by providing an HTTP interface gateway based on a standardized web platform. The web is an open standard that can perform a connecting role for different types of equipment. This article proposes a sensor node middleware to support web-based applications over a Wireless Sensor Network (WSN). We expend a WSN middleware to the web platform by providing an HTTP interface gateway. The gateway makes full duplex possible between sensor nodes and client modules. The processing results of sensor data are then presented to clients by using RIA. Our proposed middleware makes full use of the web platform's advantages and supports a wide range of various applications. The experimental results showed that the proposed middleware efficiently manages sensor nodes, and the response time for collecting sensor data is significantly reduced.