nghttpx: Enable backend pattern matching with http2-proxy

src/shrpx.cc

@@ -1543,8 +1543,7 @@ Connections:
               with "unix:" (e.g., unix:/var/run/backend.sock).
 
               Optionally, if <PATTERN>s are given, the backend address
-              is  only  used  if  request  matches  the  pattern.   If
-              --http2-proxy  is  used,  <PATTERN>s are  ignored.   The
+              is  only  used  if  request matches  the  pattern.   The
               pattern  matching is  closely  designed  to ServeMux  in
               net/http package of  Go programming language.  <PATTERN>
               consists of  path, host +  path or just host.   The path
@@ -1559,7 +1558,10 @@ Connections:
               request host.  If  host alone is given,  "/" is appended
               to it,  so that it  matches all request paths  under the
               host   (e.g.,   specifying   "nghttp2.org"   equals   to
-              "nghttp2.org/").
+              "nghttp2.org/").  CONNECT  method is  treated specially.
+              It does  not have path,  and we don't allow  empty path.
+              To workaround  this, we  assume that CONNECT  method has
+              "/" as path.
 
               Patterns with  host take  precedence over  patterns with
               just path.   Then, longer patterns take  precedence over

src/shrpx_client_handler.cc

@@ -977,18 +977,19 @@ ClientHandler::get_downstream_connection(Downstream *downstream) {
     return make_unique<HealthMonitorDownstreamConnection>();
   }
 
+  auto &balloc = downstream->get_block_allocator();
+
   // Fast path.  If we have one group, it must be catch-all group.
   // proxy mode falls in this case.
   if (groups.size() == 1) {
     group_idx = 0;
   } else if (req.method == HTTP_CONNECT) {
-    //  We don't know how to treat CONNECT request in host-path
-    //  mapping.  It most likely appears in proxy scenario.  Since we
-    //  have dealt with proxy case already, just use catch-all group.
-    group_idx = catch_all;
+    // CONNECT method does not have path.  But we requires path in
+    // host-path mapping.  As workaround, we assume that path is "/".
+    group_idx = match_downstream_addr_group(routerconf, req.authority,
+                                            StringRef::from_lit("/"), groups,
+                                            catch_all, balloc);
   } else {
-    auto &balloc = downstream->get_block_allocator();
-
     if (!req.authority.empty()) {
       group_idx = match_downstream_addr_group(
           routerconf, req.authority, req.path, groups, catch_all, balloc);

src/shrpx_config.cc

@@ -3554,19 +3554,6 @@ int configure_downstream_group(Config *config, bool http2_proxy,
     g.addrs.push_back(std::move(addr));
     router.add_route(g.pattern, addr_groups.size());
     addr_groups.push_back(std::move(g));
-  } else if (http2_proxy) {
-    // We don't support host mapping in these cases.  Move all
-    // non-catch-all patterns to catch-all pattern.
-    DownstreamAddrGroupConfig catch_all(StringRef::from_lit("/"));
-    for (auto &g : addr_groups) {
-      std::move(std::begin(g.addrs), std::end(g.addrs),
-                std::back_inserter(catch_all.addrs));
-    }
-    std::vector<DownstreamAddrGroupConfig>().swap(addr_groups);
-    // maybe not necessary?
-    routerconf = RouterConfig{};
-    router.add_route(catch_all.pattern, addr_groups.size());
-    addr_groups.push_back(std::move(catch_all));
   }
 
   // backward compatibility: override all SNI fields with the option

src/shrpx_https_upstream.cc

@@ -202,7 +202,7 @@ int htp_hdr_valcb(http_parser *htp, const char *data, size_t len) {
 namespace {
 void rewrite_request_host_path_from_uri(BlockAllocator &balloc, Request &req,
                                         const StringRef &uri,
-                                        http_parser_url &u, bool http2_proxy) {
+                                        http_parser_url &u) {
   assert(u.field_set & (1 << UF_HOST));
 
   // As per https://tools.ietf.org/html/rfc7230#section-5.4, we
@@ -271,12 +271,8 @@ void rewrite_request_host_path_from_uri(BlockAllocator &balloc, Request &req,
     }
   }
 
-  if (http2_proxy) {
-    req.path = path;
-  } else {
   req.path = http2::rewrite_clean_path(balloc, path);
 }
-}
 } // namespace
 
 namespace {
@@ -384,8 +380,7 @@ int htp_hdrs_completecb(http_parser *htp) {
         req.scheme = StringRef::from_lit("http");
       }
     } else {
-      rewrite_request_host_path_from_uri(
-          balloc, req, req.path, u, config->http2_proxy && !faddr->alt_mode);
+      rewrite_request_host_path_from_uri(balloc, req, req.path, u);
     }
   }