io.grpc.servlet

Class ServletAdapter

java.lang.Object

io.grpc.servlet.ServletAdapter

@ExperimentalApi(value="https://github.com/grpc/grpc-java/issues/5066")
public final class ServletAdapter
extends Object

An adapter that transforms HttpServletRequest into gRPC request and lets a gRPC server process it, and transforms the gRPC response into HttpServletResponse. An adapter can be instantiated by ServletServerBuilder.buildServletAdapter().

In a servlet, calling doPost(HttpServletRequest, HttpServletResponse) inside HttpServlet.doPost(HttpServletRequest, HttpServletResponse) makes the servlet backed by the gRPC server associated with the adapter. The servlet must support Asynchronous Processing and must be deployed to a container that supports servlet 4.0 and enables HTTP/2.

The API is experimental. The authors would like to know more about the real usecases. Users are welcome to provide feedback by commenting on the tracking issue.

Method Summary

Modifier and Type	Method and Description
void	destroy() Call this method when the adapter is no longer needed.
void	doGet(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp) Call this method inside HttpServlet.doGet(HttpServletRequest, HttpServletResponse) to serve gRPC GET request.
void	doPost(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp) Call this method inside HttpServlet.doPost(HttpServletRequest, HttpServletResponse) to serve gRPC POST request.
static boolean	isGrpc(javax.servlet.http.HttpServletRequest request) Checks whether an incoming HttpServletRequest may come from a gRPC client.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

doGet

public void doGet(javax.servlet.http.HttpServletRequest req,
                  javax.servlet.http.HttpServletResponse resp)
           throws IOException

Call this method inside HttpServlet.doGet(HttpServletRequest, HttpServletResponse) to serve gRPC GET request.

This method is currently not implemented.

Note that in rare case gRPC client sends GET requests.

Do not modify req and resp before or after calling this method. However, calling resp.setBufferSize() before invocation is allowed.

Throws:

IOException

doPost

public void doPost(javax.servlet.http.HttpServletRequest req,
                   javax.servlet.http.HttpServletResponse resp)
            throws IOException

Call this method inside HttpServlet.doPost(HttpServletRequest, HttpServletResponse) to serve gRPC POST request.

Do not modify req and resp before or after calling this method. However, calling resp.setBufferSize() before invocation is allowed.

Throws:

IOException

destroy

public void destroy()

Call this method when the adapter is no longer needed. The gRPC server will be terminated.

isGrpc

public static boolean isGrpc(javax.servlet.http.HttpServletRequest request)

Checks whether an incoming HttpServletRequest may come from a gRPC client.

Returns:

true if the request comes from a gRPC client