server side: smart push over HTTP

Clients can request smart push support by examining the info/refs URL
with the service parameter set to the magic git-receive-pack string:

  GET /$GIT_DIR/info/refs?service=git-receive-pack HTTP/1.1

The response is formatted with the receive pack capabilities, using
the standard packet line formatter.  A special header block is put
in front of the standard receive-pack advertisement to let clients
know the service was recognized and is supported.

If the requested service is disabled an authorization status code is
returned, allowing the user agent to retry once they have obtained
credentials from a human, in case authentication is required by
the configured ReceivePackFactory implementation.

Change-Id: Ie4f6e0c7b68a68ec4b7cdd5072f91dd406210d4f
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/GitServlet.java

@@ -47,14 +47,19 @@ import java.io.File;
 
 import javax.servlet.ServletConfig;
 import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletResponse;
 
+import org.eclipse.jgit.http.server.glue.ErrorServlet;
 import org.eclipse.jgit.http.server.glue.MetaServlet;
 import org.eclipse.jgit.http.server.glue.RegexGroupFilter;
 import org.eclipse.jgit.http.server.glue.ServletBinder;
+import org.eclipse.jgit.http.server.resolver.DefaultReceivePackFactory;
 import org.eclipse.jgit.http.server.resolver.FileResolver;
 import org.eclipse.jgit.http.server.resolver.AsIsFileService;
+import org.eclipse.jgit.http.server.resolver.ReceivePackFactory;
 import org.eclipse.jgit.http.server.resolver.RepositoryResolver;
 import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.transport.ReceivePack;
 import org.eclipse.jgit.util.StringUtils;
 
 /**
@@ -100,6 +105,8 @@ public class GitServlet extends MetaServlet {
 
 	private AsIsFileService asIs = new AsIsFileService();
 
+	private ReceivePackFactory receivePackFactory = new DefaultReceivePackFactory();
+
 	/**
 	 * New servlet that will load its base directory from {@code web.xml}.
 	 * <p>
@@ -135,6 +142,16 @@ public class GitServlet extends MetaServlet {
 		this.asIs = f != null ? f : AsIsFileService.DISABLED;
 	}
 
+	/**
+	 * @param f
+	 *            the factory to construct and configure a {@link ReceivePack}
+	 *            session when a push is requested by a client.
+	 */
+	public void setReceivePackFactory(ReceivePackFactory f) {
+		assertNotInitialized();
+		this.receivePackFactory = f != null ? f : ReceivePackFactory.DISABLED;
+	}
+
 	private void assertNotInitialized() {
 		if (initialized)
 			throw new IllegalStateException("Already initialized by container");
@@ -152,15 +169,27 @@ public class GitServlet extends MetaServlet {
 
 		initialized = true;
 
+		if (receivePackFactory != ReceivePackFactory.DISABLED) {
+			serve("*/git-receive-pack")//
+					.with(new ReceivePackServlet(receivePackFactory));
+		}
+
+		ServletBinder refs = serve("*/" + Constants.INFO_REFS);
+		if (receivePackFactory != ReceivePackFactory.DISABLED) {
+			refs = refs.through(//
+					new ReceivePackServlet.InfoRefs(receivePackFactory));
+		}
+		if (asIs != AsIsFileService.DISABLED) {
+			refs = refs.through(new IsLocalFilter());
+			refs = refs.through(new AsIsFileFilter(asIs));
+			refs.with(new InfoRefsServlet());
+		} else
+			refs.with(new ErrorServlet(HttpServletResponse.SC_FORBIDDEN));
+
 		if (asIs != AsIsFileService.DISABLED) {
 			final IsLocalFilter mustBeLocal = new IsLocalFilter();
 			final AsIsFileFilter enabled = new AsIsFileFilter(asIs);
 
-			serve("*/" + Constants.INFO_REFS)//
-					.through(mustBeLocal)//
-					.through(enabled)//
-					.with(new InfoRefsServlet());
-
 			serve("*/" + Constants.HEAD)//
 					.through(mustBeLocal)//
 					.through(enabled)//

org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/ReceivePackServlet.java

@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2009-2010, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.http.server;
+
+import static javax.servlet.http.HttpServletResponse.SC_FORBIDDEN;
+import static javax.servlet.http.HttpServletResponse.SC_INTERNAL_SERVER_ERROR;
+import static javax.servlet.http.HttpServletResponse.SC_UNAUTHORIZED;
+import static javax.servlet.http.HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE;
+import static org.eclipse.jgit.http.server.ServletUtils.getInputStream;
+import static org.eclipse.jgit.http.server.ServletUtils.getRepository;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.eclipse.jgit.http.server.resolver.ReceivePackFactory;
+import org.eclipse.jgit.http.server.resolver.ServiceNotAuthorizedException;
+import org.eclipse.jgit.http.server.resolver.ServiceNotEnabledException;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.transport.ReceivePack;
+import org.eclipse.jgit.transport.RefAdvertiser.PacketLineOutRefAdvertiser;
+
+/** Server side implementation of smart push over HTTP. */
+class ReceivePackServlet extends HttpServlet {
+	private static final String REQ_TYPE = "application/x-git-receive-pack-request";
+
+	private static final String RSP_TYPE = "application/x-git-receive-pack-result";
+
+	private static final long serialVersionUID = 1L;
+
+	static class InfoRefs extends SmartServiceInfoRefs {
+		private final ReceivePackFactory receivePackFactory;
+
+		InfoRefs(final ReceivePackFactory receivePackFactory) {
+			super("git-receive-pack");
+			this.receivePackFactory = receivePackFactory;
+		}
+
+		@Override
+		protected void advertise(HttpServletRequest req, Repository db,
+				PacketLineOutRefAdvertiser pck) throws IOException,
+				ServiceNotEnabledException, ServiceNotAuthorizedException {
+			receivePackFactory.create(req, db).sendAdvertisedRefs(pck);
+		}
+	}
+
+	private final ReceivePackFactory receivePackFactory;
+
+	ReceivePackServlet(final ReceivePackFactory receivePackFactory) {
+		this.receivePackFactory = receivePackFactory;
+	}
+
+	@Override
+	public void doPost(final HttpServletRequest req,
+			final HttpServletResponse rsp) throws IOException {
+		if (!REQ_TYPE.equals(req.getContentType())) {
+			rsp.sendError(SC_UNSUPPORTED_MEDIA_TYPE);
+			return;
+		}
+
+		final Repository db = getRepository(req);
+		final ByteArrayOutputStream out = new ByteArrayOutputStream();
+		try {
+			final ReceivePack rp = receivePackFactory.create(req, db);
+			rp.setBiDirectionalPipe(false);
+			rp.receive(getInputStream(req), out, null);
+
+		} catch (ServiceNotAuthorizedException e) {
+			rsp.sendError(SC_UNAUTHORIZED);
+			return;
+
+		} catch (ServiceNotEnabledException e) {
+			rsp.sendError(SC_FORBIDDEN);
+			return;
+
+		} catch (IOException e) {
+			getServletContext().log("Internal error during receive-pack", e);
+			rsp.sendError(SC_INTERNAL_SERVER_ERROR);
+			return;
+		}
+
+		reply(rsp, out.toByteArray());
+	}
+
+	private void reply(final HttpServletResponse rsp, final byte[] result)
+			throws IOException {
+		rsp.setContentType(RSP_TYPE);
+		rsp.setContentLength(result.length);
+		final OutputStream os = rsp.getOutputStream();
+		try {
+			os.write(result);
+			os.flush();
+		} finally {
+			os.close();
+		}
+	}
+}

org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/SmartServiceInfoRefs.java

@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2009-2010, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.http.server;
+
+import static javax.servlet.http.HttpServletResponse.SC_FORBIDDEN;
+import static javax.servlet.http.HttpServletResponse.SC_UNAUTHORIZED;
+import static org.eclipse.jgit.http.server.ServletUtils.getRepository;
+import static org.eclipse.jgit.http.server.ServletUtils.send;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.eclipse.jgit.http.server.resolver.ServiceNotAuthorizedException;
+import org.eclipse.jgit.http.server.resolver.ServiceNotEnabledException;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.transport.PacketLineOut;
+import org.eclipse.jgit.transport.RefAdvertiser.PacketLineOutRefAdvertiser;
+
+/** Filter in front of {@link InfoRefsServlet} to catch smart service requests. */
+abstract class SmartServiceInfoRefs implements Filter {
+	private final String svc;
+
+	SmartServiceInfoRefs(final String service) {
+		this.svc = service;
+	}
+
+	public void init(FilterConfig config) throws ServletException {
+		// Do nothing.
+	}
+
+	public void destroy() {
+		// Do nothing.
+	}
+
+	public void doFilter(ServletRequest request, ServletResponse response,
+			FilterChain chain) throws IOException, ServletException {
+		final HttpServletRequest req = (HttpServletRequest) request;
+
+		if (svc.equals(req.getParameter("service"))) {
+			final HttpServletResponse rsp = (HttpServletResponse) response;
+			try {
+				final Repository db = getRepository(req);
+				final ByteArrayOutputStream buf = new ByteArrayOutputStream();
+				final PacketLineOut out = new PacketLineOut(buf);
+				out.writeString("# service=" + svc + "\n");
+				out.end();
+				advertise(req, db, new PacketLineOutRefAdvertiser(out));
+				rsp.setContentType("application/x-" + svc + "-advertisement");
+				send(buf.toByteArray(), req, rsp);
+			} catch (ServiceNotAuthorizedException e) {
+				rsp.sendError(SC_UNAUTHORIZED);
+
+			} catch (ServiceNotEnabledException e) {
+				rsp.sendError(SC_FORBIDDEN);
+			}
+		} else {
+			chain.doFilter(request, response);
+		}
+	}
+
+	protected abstract void advertise(HttpServletRequest req, Repository db,
+			PacketLineOutRefAdvertiser pck) throws IOException,
+			ServiceNotEnabledException, ServiceNotAuthorizedException;
+}

org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/resolver/DefaultReceivePackFactory.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2009-2010, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.http.server.resolver;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.lib.PersonIdent;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.lib.Config.SectionParser;
+import org.eclipse.jgit.transport.ReceivePack;
+
+/**
+ * Create and configure {@link ReceivePack} service instance.
+ * <p>
+ * Writing by receive-pack is permitted if any of the following is true:
+ * <ul>
+ * <li>The container has authenticated the user and set
+ * {@link HttpServletRequest#getRemoteUser()} to the authenticated name.
+ * <li>The repository configuration file has {@code http.receivepack} explicitly
+ * set to true.
+ * </ul>
+ * and explicitly rejected otherwise.
+ */
+public class DefaultReceivePackFactory implements ReceivePackFactory {
+	private static final SectionParser<ServiceConfig> CONFIG = new SectionParser<ServiceConfig>() {
+		public ServiceConfig parse(final Config cfg) {
+			return new ServiceConfig(cfg);
+		}
+	};
+
+	private static class ServiceConfig {
+		final boolean set;
+
+		final boolean enabled;
+
+		ServiceConfig(final Config cfg) {
+			set = cfg.getString("http", null, "receivepack") != null;
+			enabled = cfg.getBoolean("http", "receivepack", false);
+		}
+	}
+
+	public ReceivePack create(final HttpServletRequest req, final Repository db)
+			throws ServiceNotEnabledException, ServiceNotAuthorizedException {
+		final ServiceConfig cfg = db.getConfig().get(CONFIG);
+		String user = req.getRemoteUser();
+
+		if (cfg.set) {
+			if (cfg.enabled) {
+				if (user == null || "".equals(user))
+					user = "anonymous";
+				return createFor(req, db, user);
+			}
+			throw new ServiceNotEnabledException();
+		}
+
+		if (user != null && !"".equals(user))
+			return createFor(req, db, user);
+		throw new ServiceNotAuthorizedException();
+	}
+
+	private ReceivePack createFor(final HttpServletRequest req,
+			final Repository db, final String user) {
+		final ReceivePack rp = new ReceivePack(db);
+		rp.setRefLogIdent(toPersonIdent(req, user));
+		return rp;
+	}
+
+	private static PersonIdent toPersonIdent(HttpServletRequest req, String user) {
+		return new PersonIdent(user, user + "@" + req.getRemoteHost());
+	}
+}

org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/resolver/ReceivePackFactory.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2009-2010, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.http.server.resolver;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.transport.ReceivePack;
+
+/** Create and configure {@link ReceivePack} service instance. */
+public interface ReceivePackFactory {
+	/** A factory disabling the ReceivePack service for all repositories. */
+	public static final ReceivePackFactory DISABLED = new ReceivePackFactory() {
+		public ReceivePack create(HttpServletRequest req, Repository db)
+				throws ServiceNotEnabledException {
+			throw new ServiceNotEnabledException();
+		}
+	};
+
+	/**
+	 * Create and configure a new ReceivePack instance for a repository.
+	 *
+	 * @param req
+	 *            current HTTP request, in case information from the request may
+	 *            help configure the ReceivePack instance.
+	 * @param db
+	 *            the repository the receive would write into.
+	 * @return the newly configured ReceivePack instance, must not be null.
+	 * @throws ServiceNotEnabledException
+	 *             this factory refuses to create the instance because it is not
+	 *             allowed on the target repository, by any user.
+	 * @throws ServiceNotAuthorizedException
+	 *             this factory refuses to create the instance for this HTTP
+	 *             request and repository, such as due to a permission error.
+	 */
+	ReceivePack create(HttpServletRequest req, Repository db)
+			throws ServiceNotEnabledException, ServiceNotAuthorizedException;
+}