applied a modified version of neilljordan 's patch to add support for multi-value response headers returned from subrquests.

README.markdown

@@ -620,7 +620,17 @@ Here's a basic example:
 Returns a Lua table with three slots (`res.status`, `res.header`, and `res.body`).
 
 `res.header` holds all the response headers of the
-subrequest and it is a normal Lua table.
+subrequest and it is a normal Lua table. For multi-value response headers,
+the value is a Lua (array) table that holds all the values in the order that
+they appear. For instance, if the subrequest response headers contains the following
+lines:
+
+    Set-Cookie: a=3
+    Set-Cookie: foo=bar
+    Set-Cookie: baz=blah
+
+Then `res.header["Set-Cookie"]` will be evaluted to the table value
+`{"a=3", "foo=bar", "baz=blah"}`.
 
 URI query strings can be concatenated to URI itself, for instance,
 

src/ngx_http_lua_util.c

@@ -1178,11 +1178,40 @@ ngx_http_lua_wev_handler(ngx_http_request_t *r)
 
         lua_pushlstring(cc, (char *) header[i].key.data,
                 header[i].key.len); /* header key */
+        lua_pushvalue(cc, -1); /* stack: table key key */
 
-        lua_pushlstring(cc, (char *) header[i].value.data,
-                header[i].value.len); /* header key value */
+        /* check if header already exists */
+        lua_rawget(cc, -3); /* stack: table key value */
 
-        lua_rawset(cc, -3); /* head */
+        if (lua_isnil(cc, -1)) {
+            lua_pop(cc, 1); /* stack: table key */
+
+            lua_pushlstring(cc, (char *) header[i].value.data,
+                    header[i].value.len); /* stack: table key value */
+
+            lua_rawset(cc, -3); /* stack: table */
+
+        } else {
+            if (! lua_istable(cc, -1)) { /* already inserted one value */
+                lua_createtable(cc, 4, 0); /* stack: table key value table */
+                lua_insert(cc, -2); /* stack: table key table value */
+                lua_rawseti(cc, -2, 1); /* stack: table key table */
+
+                lua_pushlstring(cc, (char *) header[i].value.data,
+                        header[i].value.len); /* stack: table key table value */
+
+                lua_rawseti(cc, -2, lua_objlen(cc, -2) + 1); /* stack: table key table */
+
+                lua_rawset(cc, -3); /* stack: table */
+
+            } else {
+                lua_pushlstring(cc, (char *) header[i].value.data,
+                        header[i].value.len); /* stack: table key table value */
+
+                lua_rawseti(cc, -2, lua_objlen(cc, -2) + 1); /* stack: table key table */
+                lua_pop(cc, 2); /* stack: table */
+            }
+        }
     }
 
     lua_setfield(cc, -2, "header");

t/002-content.t

@@ -405,7 +405,34 @@ type: foo/bar
 
 
 
-=== TEST 24: capture location headers
+=== TEST 24: capture location multi-value headers
+--- config
+    location /other {
+        #echo "hello, world";
+        content_by_lua '
+            ngx.header["Set-Cookie"] = {"a", "hello, world", "foo"}
+            ngx.eof()
+        ';
+    }
+
+    location /lua {
+        content_by_lua '
+            res = ngx.location.capture("/other");
+            ngx.say("type: ", type(res.header["Set-Cookie"]));
+            ngx.say("len: ", #res.header["Set-Cookie"]);
+            ngx.say("value: ", table.concat(res.header["Set-Cookie"], "|"))
+        ';
+    }
+--- request
+GET /lua
+--- response_body
+type: table
+len: 3
+value: a|hello, world|foo
+
+
+
+=== TEST 25: capture location headers
 --- config
     location /other {
         default_type 'foo/bar';
@@ -429,7 +456,7 @@ Bar: Bah
 
 
 
-=== TEST 25: capture location headers
+=== TEST 26: capture location headers
 --- config
     location /other {
         default_type 'foo/bar';