Add basic web server framework

BUILD

@@ -7,6 +7,15 @@ java_library(
     "@maven//:net_minidev_json_smart",
   ],
 )
+java_library(
+	name = "webserver_lib",
+  srcs = glob(["src/webserver/*.java"]),
+  deps = [
+    ":duckutil_lib",
+    "@maven//:net_minidev_json_smart",
+  ],
+)
+
 
 java_library(
 	name = "importtool_lib",

src/webserver/DuckWebServer.java

@@ -0,0 +1,53 @@
+package duckutil.webserver;
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpServer;
+import duckutil.TaskMaster;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.util.logging.Logger;
+
+public class DuckWebServer
+{
+  private static final Logger logger = Logger.getLogger("duckutil.webserver");
+  private final HttpServer http_server;
+  private final WebHandler handler;
+
+  public DuckWebServer(String web_host, int web_port, WebHandler handler, int threads)
+    throws IOException
+  {
+    InetSocketAddress listen = new InetSocketAddress(web_port);
+    if (web_host != null)
+    {
+      listen = new InetSocketAddress(web_host, web_port);
+    }
+
+    this.handler = handler;
+
+    http_server = HttpServer.create(listen, 16);
+    http_server.createContext("/", new RootHandler());
+    http_server.setExecutor(TaskMaster.getBasicExecutor(threads,"web_server"));
+    http_server.start();
+  }
+
+  public class RootHandler implements HttpHandler
+  {
+    public void handle(HttpExchange t) throws IOException 
+    {
+      try(WebContext ctx = new WebContext(t))
+      {
+        try
+        {
+          handler.handle(ctx);
+        }
+        catch(Exception e)
+        {
+          ctx.setException(e);
+        }
+      }
+
+    }
+  }
+
+}

src/webserver/WebContext.java

@@ -0,0 +1,108 @@
+package duckutil.webserver;
+
+import com.sun.net.httpserver.HttpExchange;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.net.URI;
+import java.util.logging.Logger;
+
+public class WebContext implements AutoCloseable
+{
+  private static final Logger logger = Logger.getLogger("duckutil.webserver");
+
+  private final HttpExchange http_exchange;
+
+  private int http_code=500;
+  private String content_type="text/plain";
+  private int output_size = -1;
+
+  private ByteArrayOutputStream output_buffer = new ByteArrayOutputStream();
+  private PrintStream print_out = new PrintStream(output_buffer);
+
+  private boolean out_written;
+
+  // Things that needs to be set
+  //  size
+  //  content-type
+  //  http code
+
+  public WebContext(HttpExchange t)
+  {
+    this.http_exchange = t;
+    logger.info("Request - " + getURI());
+
+  }
+
+  public URI getURI()
+  {
+    return http_exchange.getRequestURI();
+  }
+  public String getHost()
+  {
+    return http_exchange.getRequestHeaders().get("Host").get(0);
+  }
+
+  public InputStream getRequestBody() { return http_exchange.getRequestBody(); }
+
+  public void setHttpCode(int code) { http_code = code; }
+  public void setContentType(String type) { content_type = type; }
+  public void setOutputSize(int size) { output_size = size; }
+
+  public void setException(Throwable t)
+  {
+    setHttpCode(500);
+    setContentType("text/plain");
+    out().println(t);
+
+  }
+
+  public PrintStream out(){return print_out; }
+
+  public void writeHeaders()
+    throws java.io.IOException
+  {
+    if (output_size < 0)
+    {
+      output_size = output_buffer.toByteArray().length;
+    }
+
+    logger.info(String.format("HTTP result: %s code:%d sz:%d", content_type, http_code, output_size));
+    http_exchange.getResponseHeaders().add("Content-type",content_type);
+    http_exchange.sendResponseHeaders( http_code, output_size);
+
+  }
+
+  /**
+   * If this is used, do setOutputSize() then writeHeaders() first
+   */
+  public OutputStream getOutStream()
+  {
+    out_written=true;
+    return http_exchange.getResponseBody();
+  }
+
+  public void close()
+  {
+    try
+    {
+      if (!out_written)
+      {
+        writeHeaders();
+        byte[] data = output_buffer.toByteArray();
+        OutputStream out = http_exchange.getResponseBody();
+        out.write(data);
+        out.close();
+        out_written = true;
+      }
+    }
+    catch(java.io.IOException e)
+    {
+      logger.info(e.toString());
+    }
+
+  }
+
+}

src/webserver/WebHandler.java

@@ -0,0 +1,9 @@
+package duckutil.webserver;
+
+public interface WebHandler
+{
+  public void handle(WebContext t) throws Exception;
+
+}
+
+