When developing solutions based on the Internet of Things (IoT) architecture and its accompanying software ecosystem, there is a frequent need to rigorously test backend server applications. To streamline this process, a custom desktop HTTP Tester utility was developed.
The program allows the user to specify the target server’s address and port. The address can be entered either as a domain name or a direct IP address. The tool provides the flexibility to select pre-configured HTTP headers and payload data from a library of ready-made presets (useful for regression testing previously implemented projects), or to manually input custom raw data when developing and debugging new projects.
To minimize human error during manual payload entry, the utility includes a feature to automatically calculate and inject the correct Content-Length value into the HTTP header.
Operating Principle
The user inputs the server address and port of the backend application being tested, then selects or types the parameters (headers and payload) to be sent. The HTTP header and the request body (data payload) are split into separate input fields. The interface dynamically updates based on the user’s selections. If the automatic calculation checkbox is enabled, the Content-Length field within the header is dynamically recalculated in real-time based on the exact byte size of the payload body.
Upon clicking the “Send” button, assuming the inputs are valid, a TCP connection is established with the target server application at the specified address and port. Once successfully connected, the header and payload are transmitted. The server processes the request and returns an HTTP response, which the utility receives, parses, displays in the response pane, and then gracefully closes the connection.
This workflow allows developers to thoroughly test and validate the server application by simulating diverse, user-modifiable data payloads and analyzing the raw server responses.
The utility is written entirely in C++ utilizing the WinAPI and Windows Sockets API (WSA / WinSock).
Field Testing and Application
This testing utility was successfully used to verify functionality and aggressively debug the following backend solutions:
- IoT Request Forwarding Server Application;
- Server backend for the Tenko Boilers IoT solution;
- Server backend for the Cleancar Self-Service Car Wash IoT solution.