The response object contains methods for reading and setting headers, status code and body (amongst other things). In the next section you will encounter the most important methods of the response object. If you need more information please refer to the javadoc.

The rsp.send method is responsible for sending and writing data into the HTTP response.

A renderer is responsible for converting a Java Object into something else (json, html, etc..).

Let's consider a simple example:

get("/", (req, rsp) -> rsp.send("hey jooby"));

get("/", req -> "hey jooby"); // or just return a value and Jooby will call send for you.

The send method will ask the Renderer API to format an object and write a response.

The resulting Content-Type when not set is text/html.

The resulting Status Code when not set is 200.

Some examples:

get("/", req -> {
   // text/html with 200
   String data = ...;
   return data;
});

get("/", (req, rsp) -> {
   // text/plain with 200 explicitly 
   String data = ...;
   rsp.status(200)
        .type("text/plain")
        .send(data);
});

Alternative:

get("/", req -> {
   // text/plain with 200 explicitly 
   String data = ...;
   return Results.with(data, 200)
        .type("text/plain");
});

Retrieval of response headers is done via rsp.header("name"). This method returns a Mutant which can be converted to any of the supported types.

Setting a header is pretty straightforward as well:

rsp.header("Header-Name", value).header("Header2", value);

The send file API is available through the rsp.download* methods:

{
  get("/download", (req, rsp) -> {
    rsp.download("myfile", new File(...));
  });
}

The download method sets the following headers:

• Content-Disposition

• Content-Length

• Content-Type

In the next example we explicitly set some of these:

{
  get("/download", (req, rsp) -> {
    rsp
      .type("text/plain")
      .header("Content-Disposition", "attachment; filename=myfile.txt;")
      .download(new File(...));
  });
}