Lightweight Java HTTP Server
A bottom-up approach to learn the network programming in Java core, by creating my own server library.
Why?
I build this for my LINE Bot webhook server which will be rewritten in Java, Servlet APIs / JavaEE stuff is too heavy-weight, super complex and f*cking verbose and Java 8 SE is lacking a built-in simple HTTP handler.
How to use com.tuhuynh.httpserver
(thanks Github Packages <3)
- Add this to pom.xml:
<dependency>
<groupId>com.tuhuynh</groupId>
<artifactId>httpserver</artifactId>
<version>0.1.4-ALPHA</version>
</dependency>
or build.gradle:
compile group: 'com.tuhuynh', name: 'httpserver', version: '0.1.4-ALPHA'
- Use it (Java 8 compatible!)
(It's easy to use like a Node.js Express server or Golang's built-in net/http package)
Note: This HTTP Server library is inspired by LINE's Armeria
public final class LightWeightServer {
public static void main(String[] args) throws IOException {
final HTTPServer server = HTTPServer.port(8080);
server.get("/", ctx -> HttpResponse.of("Hello World"));
server.post("/echo", ctx -> HttpResponse.of(ctx.getPayload()));
// Free to execute blocking tasks with a Cached ThreadPool
server.get("/sleep", ctx -> {
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
System.out.println(e.getMessage());
}
return HttpResponse.of("Sleep done!");
});
server.get("/thread",
ctx -> HttpResponse.of(Thread.currentThread().getName()));
server.get("/random", ctx -> {
final Random rand = new Random();
return HttpResponse.of(String.valueOf(rand.nextInt(100 + 1)));
});
// Get query params, ex: /query?hello=world
server.get("/query", ctx -> {
final String world = ctx.getQueryParams().get("hello");
return HttpResponse.of("Hello: " + world);
});
// Middleware support: Sample JWT Verify Middleware
RequestHandler jwtValidator = ctx -> {
final String authorizationHeader = ctx.getHeader().get("Authorization");
// Check JWT is valid, below is just a sample check
if (!authorizationHeader.startsWith("Bearer")) {
return HttpResponse.reject("Invalid token").status(401);
}
ctx.putHandlerData("username", "tuhuynh");
return HttpResponse.next();
};
// Then,
// Inject middleware to the request function chain
server.get("/protected",
jwtValidator, // jwtMiddleware
ctx -> HttpResponse.of("Login success, hello: " + ctx.getHandlerData("username")));
// Perform as a proxy server
server.get("/meme", ctx -> {
// Built-in HTTP Client
final ResponseObject
meme = HTTPClient.builder()
.url("https://meme-api.herokuapp.com/gimme").method("GET")
.build().perform();
return HttpResponse.of(meme.getBody());
});
// Handle error
server.get("/panic", ctx -> {
throw new Exception("Panicked!");
});
server.start();
}
}
(after build: size is just 30-50 KB .jar file, run and init cost about 20-30MB RAM)
Changelogs
0.1.0-ALPHA
- A very naive and basic HTTP Server
- Raw implementation, lightweight & no dependency
- Listen on a given TCP Port
- Easy to add a handler with a (Method/Path/Functional_Handler) define
- Handled inside with a Cached ThreadPool
0.1.1-ALPHA
- Add HttpResponse Object for handling response struct
- Remove redundant constant and lombok usage
0.1.2-ALPHA
- Add built-in HTTP Client
- Refactor code
0.1.3-ALPHA
- Support default error handling
- Support get query params from Context
- Improve HTTP Client response
0.1.4-ALPHA
- Support HTTP Middleware functions chain (like Node.js Express and Go)
Up coming:
- Improve the request context with extra routing pattern matching (path: /request/:path)
- Support annotation to decorate the code (@Handler @Router)
- Support an NIO (Non Blocking I/O) HTTP Server & Client based on
java.nio - Support built-in JSON marshall/unmarshall support
Dependencies
Zero dependency, it just uses the Java core built-in APIs, also lombok is used to compile and build the library.
Lines of code: 428
39 ./src/main/java/com/tuhuynh/httpserver/HTTPServer.java
140 ./src/main/java/com/tuhuynh/httpserver/utils/HandlerUtils.java
74 ./src/main/java/com/tuhuynh/httpserver/HTTPClient.java
61 ./src/main/java/com/tuhuynh/httpserver/handlers/HandlerPipeline.java
101 ./src/main/java/com/tuhuynh/httpserver/handlers/HandlerBinder.java
428 total
