Echo API
A maven library of a /echo API that echoes HTTP request’s details back to the caller.
The need for this library arose when I wanted assurance that my HTTP client was sending correctly formulated HTTP messages.
Another use of this /echo API is to capture and debug the remote calls from another service. Imagine you are providing a webhook endpoint. Before you even build one, you first need to know what incoming messages look like. Supplying an /echo API endpoint in the webhook’s registration allows you to capture and log all incoming messages
Demo
You can open https://echook.azurewebsites.net/echo on your browser, Postman, or call it from an API to see the /echo in action
Note: This site is hosted on Azure free tier. If it is a while since its last execution, it may take some time to respond. Otherwise, you can clone the https://github.com/geraldnguyen/echo-server project and run the application locally
Integration
pom.xml
<dependency>
<groupId>io.github.geraldnguyen</groupId>
<artifactId>echo</artifactId>
<version>1.0.0</version>
</dependency>EchoServerApplication.java
import nguyen.gerald.echo.EnableEchoController;
@SpringBootApplication
@EnableEchoController
public class EchoServerApplication {
public static void main(String[] args) {
SpringApplication.run(EchoServerApplication.class, args);
}
}Features
The following information is echoed back in JSON format:
- Path
- Protocol
- Headers
- Query string
- URL-encoded form submission
- Multi-part form submission
Limitation
The parsing of the query string and URL-encoded body depends on a deprecated class HttpUtils that supports only default encoding. The extraction code also does not handle malformed strings well.
Hash fragment (#abc)
Browser does not include hash fragment in the HTTP request message. Java servlet specification does not provide any way to extract the original URL either.
Hence there is no way to extract and echo hash fragment back.
