Package io.undertow.servlet.handlers

Class DefaultServlet

java.lang.Object
jakarta.servlet.GenericServlet
jakarta.servlet.http.HttpServlet
io.undertow.servlet.handlers.DefaultServlet
All Implemented Interfaces:
Servlet, ServletConfig, Serializable
public class DefaultServlet extends HttpServlet
Default servlet responsible for serving up resources. This is both a handler and a servlet. If no filters match the current path then the resources will be served up asynchronously using the HttpHandler.handleRequest(io.undertow.server.HttpServerExchange) method, otherwise the request is handled as a normal servlet request.

By default we only allow a restricted set of extensions.

todo: this thing needs a lot more work. In particular: - caching for blocking requests - correct mime type - range/last-modified and other headers to be handled properly - head requests - and probably heaps of other things
Author:
Stuart Douglas
See Also:

  • Field Details

  • Constructor Details

    • DefaultServlet

      public DefaultServlet()

  • Method Details

    • init

      public void init(ServletConfig config) throws ServletException
      Description copied from class: GenericServlet
      Called by the servlet container to indicate to a servlet that the servlet is being placed into service. See Servlet.init(jakarta.servlet.ServletConfig).

      This implementation stores the ServletConfig object it receives from the servlet container for later use. When overriding this form of the method, call super.init(config).

      Specified by:
      init in interface Servlet
      Overrides:
      init in class HttpServlet
      Parameters:
      config - the ServletConfig object that contains configuration information for this servlet
      Throws:
      ServletException - if an exception occurs that interrupts the servlet's normal operation
      See Also:

    • doGet

      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
      Description copied from class: HttpServlet
      Called by the server (via the service method) to allow a servlet to handle a GET request.

      Overriding this method to support a GET request also automatically supports an HTTP HEAD request. A HEAD request is a GET request that returns no body in the response, only the request header fields.

      When overriding this method, read the request data, write the response headers, get the response's writer or output stream object, and finally, write the response data. It's best to include content type and encoding. When using a PrintWriter object to return the response, set the content type before accessing the PrintWriter object.

      The servlet container must write the headers before committing the response, because in HTTP the headers must be sent before the response body.

      Where possible, set the Content-Length header (with the ServletResponse.setContentLength(int) method), to allow the servlet container to use a persistent connection to return its response to the client, improving performance. The content length is automatically set if the entire response fits inside the response buffer.

      When using HTTP 1.1 chunked encoding (which means that the response has a Transfer-Encoding header), do not set the Content-Length header.

      The GET method should be safe, that is, without any side effects for which users are held responsible. For example, most form queries have no side effects. If a client request is intended to change stored data, the request should use some other HTTP method.

      The GET method should also be idempotent, meaning that it can be safely repeated. Sometimes making a method safe also makes it idempotent. For example, repeating queries is both safe and idempotent, but buying a product online or modifying data is neither safe nor idempotent.

      If the request is incorrectly formatted, doGet returns an HTTP "Bad Request" message.

      Overrides:
      doGet in class HttpServlet
      Parameters:
      req - an HttpServletRequest object that contains the request the client has made of the servlet
      resp - an HttpServletResponse object that contains the response the servlet sends to the client
      Throws:
      ServletException - if the request for the GET could not be handled
      IOException - if an input or output error is detected when the servlet handles the GET request
      See Also:

    • doPost

      protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
      Description copied from class: HttpServlet
      Called by the server (via the service method) to allow a servlet to handle a POST request. The HTTP POST method allows the client to send data of unlimited length to the Web server a single time and is useful when posting information such as credit card numbers.

      When overriding this method, read the request data, write the response headers, get the response's writer or output stream object, and finally, write the response data. It's best to include content type and encoding. When using a PrintWriter object to return the response, set the content type before accessing the PrintWriter object.

      The servlet container must write the headers before committing the response, because in HTTP the headers must be sent before the response body.

      Where possible, set the Content-Length header (with the ServletResponse.setContentLength(int) method), to allow the servlet container to use a persistent connection to return its response to the client, improving performance. The content length is automatically set if the entire response fits inside the response buffer.

      When using HTTP 1.1 chunked encoding (which means that the response has a Transfer-Encoding header), do not set the Content-Length header.

      This method does not need to be either safe or idempotent. Operations requested through POST can have side effects for which the user can be held accountable, for example, updating stored data or buying items online.

      If the HTTP POST request is incorrectly formatted, doPost returns an HTTP "Bad Request" message.

      Overrides:
      doPost in class HttpServlet
      Parameters:
      req - an HttpServletRequest object that contains the request the client has made of the servlet
      resp - an HttpServletResponse object that contains the response the servlet sends to the client
      Throws:
      ServletException - if the request for the POST could not be handled
      IOException - if an input or output error is detected when the servlet handles the request
      See Also:

    • doPut

      protected void doPut(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
      Description copied from class: HttpServlet
      Called by the server (via the service method) to allow a servlet to handle a PUT request. The PUT operation allows a client to place a file on the server and is similar to sending a file by FTP.

      When overriding this method, leave intact any content headers sent with the request (including Content-Length, Content-Type, Content-Transfer-Encoding, Content-Encoding, Content-Base, Content-Language, Content-Location, Content-MD5, and Content-Range). If your method cannot handle a content header, it must issue an error message (HTTP 501 - Not Implemented) and discard the request. For more information on HTTP 1.1 and the PUT method, see RFC 7231 .

      This method does not need to be either safe or idempotent. Operations that doPut performs can have side effects for which the user can be held accountable. When using this method, it may be useful to save a copy of the affected URL in temporary storage.

      If the HTTP PUT request is incorrectly formatted, doPut returns an HTTP "Bad Request" message.

      Overrides:
      doPut in class HttpServlet
      Parameters:
      req - the HttpServletRequest object that contains the request the client made of the servlet
      resp - the HttpServletResponse object that contains the response the servlet returns to the client
      Throws:
      ServletException - if the request for the PUT cannot be handled
      IOException - if an input or output error occurs while the servlet is handling the PUT request

    • doDelete

      protected void doDelete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
      Description copied from class: HttpServlet
      Called by the server (via the service method) to allow a servlet to handle a DELETE request. The DELETE operation allows a client to remove a document or Web page from the server.

      This method does not need to be either safe or idempotent. Operations requested through DELETE can have side effects for which users can be held accountable. When using this method, it may be useful to save a copy of the affected URL in temporary storage.

      If the HTTP DELETE request is incorrectly formatted, doDelete returns an HTTP "Bad Request" message.

      Overrides:
      doDelete in class HttpServlet
      Parameters:
      req - the HttpServletRequest object that contains the request the client made of the servlet
      resp - the HttpServletResponse object that contains the response the servlet returns to the client
      Throws:
      ServletException - if the request for the DELETE cannot be handled
      IOException - if an input or output error occurs while the servlet is handling the DELETE request

    • doOptions

      protected void doOptions(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
      Description copied from class: HttpServlet
      Called by the server (via the service method) to allow a servlet to handle a OPTIONS request. The OPTIONS request determines which HTTP methods the server supports and returns an appropriate header. For example, if a servlet overrides doGet, this method returns the following header:

      Allow: GET, HEAD, TRACE, OPTIONS

      There's no need to override this method unless the servlet implements new HTTP methods, beyond those implemented by HTTP 1.1.

      Overrides:
      doOptions in class HttpServlet
      Parameters:
      req - the HttpServletRequest object that contains the request the client made of the servlet
      resp - the HttpServletResponse object that contains the response the servlet returns to the client
      Throws:
      ServletException - if the request for the OPTIONS cannot be handled
      IOException - if an input or output error occurs while the servlet is handling the OPTIONS request

    • doTrace

      protected void doTrace(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
      Description copied from class: HttpServlet
      Called by the server (via the service method) to allow a servlet to handle a TRACE request. A TRACE returns the headers sent with the TRACE request to the client, so that they can be used in debugging. There's no need to override this method.
      Overrides:
      doTrace in class HttpServlet
      Parameters:
      req - the HttpServletRequest object that contains the request the client made of the servlet
      resp - the HttpServletResponse object that contains the response the servlet returns to the client
      Throws:
      ServletException - if the request for the TRACE cannot be handled
      IOException - if an input or output error occurs while the servlet is handling the TRACE request