public void doFilter()

in java/com/google/gitiles/GitwebRedirectFilter.java [64:138]
64 lines of code
25 McCabe index (conditional complexity)

  public void doFilter(HttpServletRequest req, HttpServletResponse res, FilterChain chain)
      throws IOException, ServletException {
    GitilesView gitwebView = ViewFilter.getView(req);
    if (!isGitwebStyleQuery(req)) {
      chain.doFilter(req, res);
      return;
    }

    ListMultimap<String, String> params = parse(req.getQueryString());
    String action = getFirst(params, "a");
    String project = getFirst(params, "p");
    String path = Strings.nullToEmpty(getFirst(params, "f"));

    // According to gitweb's perl source code, the primary parameters are these
    // short abbreviated names. When pointing to blob or subtree hash,hashParent
    // are the blob or subtree SHA-1s and hashBase,hashParentBase are commits.
    // When pointing to commits or tags, hash is the commit/tag. Its messy.
    Revision hash = toRevision(getFirst(params, "h"));
    Revision hashBase = toRevision(getFirst(params, "hb"));
    Revision hashParent = toRevision(getFirst(params, "hp"));
    Revision hashParentBase = toRevision(getFirst(params, "hpb"));

    GitilesView.Builder view;
    if ("project_index".equals(action)) {
      view = GitilesView.hostIndex();
      project = null;
    } else if ("summary".equals(action) || "tags".equals(action)) {
      view = GitilesView.repositoryIndex();
    } else if (("commit".equals(action) || "tag".equals(action)) && hash != null) {
      view = GitilesView.revision().setRevision(hash);
    } else if ("log".equals(action) || "shortlog".equals(action)) {
      view = GitilesView.log().setRevision(firstNonNull(hash, Revision.HEAD));
    } else if ("tree".equals(action)) {
      view =
          GitilesView.path().setRevision(firstNonNull(hashBase, Revision.HEAD)).setPathPart(path);
    } else if (("blob".equals(action) || "blob_plain".equals(action))
        && hashBase != null
        && !path.isEmpty()) {
      view = GitilesView.path().setRevision(hashBase).setPathPart(path);
    } else if ("commitdiff".equals(action) && hash != null) {
      view =
          GitilesView.diff()
              .setOldRevision(firstNonNull(hashParent, Revision.NULL))
              .setRevision(hash)
              .setPathPart("");
    } else if ("blobdiff".equals(action)
        && !path.isEmpty()
        && hashParentBase != null
        && hashBase != null) {
      view =
          GitilesView.diff().setOldRevision(hashParentBase).setRevision(hashBase).setPathPart(path);
    } else if ("history".equals(action) && !path.isEmpty()) {
      view = GitilesView.log().setRevision(firstNonNull(hashBase, Revision.HEAD)).setPathPart(path);
    } else {
      // Gitiles does not provide an RSS feed (a=rss,atom,opml)
      // Any other URL is out of date and not valid anymore.
      throw new GitilesRequestFailureException(FailureReason.UNSUPPORTED_GITWEB_URL);
    }

    if (!Strings.isNullOrEmpty(project)) {
      view.setRepositoryName(cleanProjectName(project));
    }

    String url;
    try {
      url =
          view.setHostName(gitwebView.getHostName())
              .setServletPath(gitwebView.getServletPath())
              .toUrl();
    } catch (InvalidViewException e) {
      throw new GitilesRequestFailureException(FailureReason.UNSUPPORTED_GITWEB_URL, e);
    }
    res.setStatus(SC_MOVED_PERMANENTLY);
    res.setHeader(LOCATION, url);
  }