| // Copyright 2021 Google LLC. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package com.google.gitiles; |
| |
| import static com.google.common.net.HttpHeaders.LOCATION; |
| import static com.google.gitiles.FormatType.HTML; |
| import static javax.servlet.http.HttpServletResponse.SC_MOVED_PERMANENTLY; |
| import static org.eclipse.jgit.http.server.ServletUtils.ATTRIBUTE_REPOSITORY; |
| |
| import java.io.IOException; |
| import java.util.Optional; |
| import javax.servlet.FilterChain; |
| import javax.servlet.ServletException; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| import org.eclipse.jgit.http.server.ServletUtils; |
| import org.eclipse.jgit.lib.Repository; |
| |
| /** |
| * Filter to replace the URL string that contains a branch name to a new branch name. The updated |
| * branch mapping is provided by {@code BranchRedirectFilter#getRedirectBranch} method If it updates |
| * the branch it then returns the new URL with updated branch name as redirect. |
| * |
| * <p>This implementation does not provide a branch redirect mapping. Hence including this filter |
| * as-is would be a no-op. To make this effective {@code BranchRedirectFilter#getRedirectBranch} |
| * needs to be overridden that provides a mapping to the requested repo/branch. |
| */ |
| public class BranchRedirectFilter extends AbstractHttpFilter { |
| /** |
| * Provides an extendable interface that can be used to provide implementation for determining |
| * redirect branch |
| * |
| * @param repo Repository |
| * @param sourceBranch full branch name eg. refs/heads/master |
| * @return Returns the branch that should be redirected to on a given repo. {@code |
| * Optional.empty()} means no redirect. |
| */ |
| protected Optional<String> getRedirectBranch(Repository repo, String sourceBranch) { |
| return Optional.empty(); |
| } |
| |
| private Optional<String> rewriteRevision(Repository repo, Revision rev) { |
| if (Revision.isNull(rev)) { |
| return Optional.empty(); |
| } |
| return getRedirectBranch(repo, rev.getName()); |
| } |
| |
| private static Revision rewriteRevision(Revision revision, Optional<String> targetBranch) { |
| if (!targetBranch.isPresent()) { |
| return revision; |
| } |
| |
| return new Revision( |
| targetBranch.get(), |
| revision.getId(), |
| revision.getType(), |
| revision.getPeeledId(), |
| revision.getPeeledType()); |
| } |
| |
| @Override |
| public void doFilter(HttpServletRequest req, HttpServletResponse res, FilterChain chain) |
| throws IOException, ServletException { |
| if (!hasRepository(req) || isForAutomation(req)) { |
| chain.doFilter(req, res); |
| return; |
| } |
| |
| GitilesView view = ViewFilter.getView(req); |
| Repository repo = ServletUtils.getRepository(req); |
| |
| Optional<String> rewrittenRevision = rewriteRevision(repo, view.getRevision()); |
| Optional<String> rewrittenOldRevision = rewriteRevision(repo, view.getOldRevision()); |
| |
| if (!rewrittenRevision.isPresent() && !rewrittenOldRevision.isPresent()) { |
| chain.doFilter(req, res); |
| return; |
| } |
| |
| Revision rev = rewriteRevision(view.getRevision(), rewrittenRevision); |
| Revision oldRev = rewriteRevision(view.getOldRevision(), rewrittenOldRevision); |
| if (rev.equals(view.getRevision()) && oldRev.equals(view.getOldRevision())) { |
| chain.doFilter(req, res); |
| return; |
| } |
| |
| String url = view.toBuilder().setRevision(rev).setOldRevision(oldRev).toUrl(); |
| res.setStatus(SC_MOVED_PERMANENTLY); |
| res.setHeader(LOCATION, url); |
| } |
| |
| private static boolean hasRepository(HttpServletRequest req) { |
| return req.getAttribute(ATTRIBUTE_REPOSITORY) != null; |
| } |
| |
| private static boolean isForAutomation(HttpServletRequest req) { |
| return !FormatType.getFormatType(req).orElse(HTML).equals(HTML); |
| } |
| } |