Additional helper functions for request transform

doc/admin-guide/plugins/lua.en.rst

@@ -2804,7 +2804,7 @@ ts.http.resp_transform.get_upstream_bytes
 -----------------------------------------
 **syntax:** *ts.http.resp_transform.get_upstream_bytes()*
 
-**context:** transform handler
+**context:** transform handler for response
 
 **description**: This function can be used to retrieve the total bytes to be received from the upstream. If we got
 chunked response body from origin server, TS_LUA_INT64_MAX will be returned.
@@ -2848,7 +2848,7 @@ ts.http.resp_transform.get_upstream_watermark_bytes
 ---------------------------------------------------
 **syntax:** *ts.http.resp_transform.get_upstream_watermark_bytes()*
 
-**context:** transform handler
+**context:** transform handler for response
 
 **description**: This function can be used to retrieve the current watermark bytes for the upstream transform buffer.
 
@@ -2859,7 +2859,7 @@ ts.http.resp_transform.set_upstream_watermark_bytes
 ---------------------------------------------------
 **syntax:** *ts.http.resp_transform.set_upstream_watermark_bytes(NUMBER)*
 
-**context:** transform handler
+**context:** transform handler for response
 
 **description**: This function can be used to set the watermark bytes of the upstream transform buffer.
 
@@ -2872,14 +2872,94 @@ ts.http.resp_transform.set_downstream_bytes
 -------------------------------------------
 **syntax:** *ts.http.resp_transform.set_downstream_bytes(NUMBER)*
 
-**context:** transform handler
+**context:** transform handler for response
 
 **description**: This function can be used to set the total bytes to be sent to the downstream.
 
 Sometimes we want to set Content-Length header in client_response, and this function should be called before any real
 data is returned from the transform handler.
 
 
+:ref:`TOP <admin-plugins-ts-lua>`
+
+ts.http.req_transform.get_downstream_bytes
+------------------------------------------
+**syntax:** *ts.http.req_transform.get_downstream_bytes()*
+
+**context:** transform handler for request
+
+**description**: This function can be used to retrieve the total bytes to be received from downstream.
+
+Here is an example:
+
+::
+
+    function transform_print(data, eos)
+      ts.ctx['reqbody'] = ts.ctx['reqbody'] .. data
+
+      if ts.ctx['len_set'] == nil then
+        local sz = ts.http.req_transform.get_downstream_bytes()
+        ts.http.req_transform.set_upstream_bytes(sz)
+        ts.ctx['len_set'] = true
+      end
+
+      if (eos == 1) then
+        ts.debug('End of Stream and the reqbody is ... ')
+        ts.debug(ts.ctx['reqbody'])
+      end
+
+      return data, eos
+    end
+
+    function do_remap()
+      if (ts.client_request.get_method() == 'POST') then
+        ts.ctx['reqbody'] = ''
+        ts.hook(TS_LUA_REQUEST_TRANSFORM, transform_print)
+      end
+
+      return 0
+    end
+
+The above example also shows the use of eos passed as a parameter to transform function. It indicates the end of the
+data stream to the transform function.
+
+:ref:`TOP <admin-plugins-ts-lua>`
+
+ts.http.req_transform.get_downstream_watermark_bytes
+----------------------------------------------------
+**syntax:** *ts.http.req_transform.get_downstream_watermark_bytes()*
+
+**context:** transform handler for request
+
+**description**: This function can be used to retrieve the current watermark bytes for the downstream transform buffer.
+
+
+:ref:`TOP <admin-plugins-ts-lua>`
+
+ts.http.req_transform.set_downstream_watermark_bytes
+----------------------------------------------------
+**syntax:** *ts.http.req_transform.set_downstream_watermark_bytes(NUMBER)*
+
+**context:** transform handler for request
+
+**description**: This function can be used to set the watermark bytes of the downstream transform buffer.
+
+Setting the watermark bytes above 32kb may improve the performance of the transform handler.
+
+
+:ref:`TOP <admin-plugins-ts-lua>`
+
+ts.http.req_transform.set_upstream_bytes
+----------------------------------------
+**syntax:** *ts.http.req_transform.set_upstream_bytes(NUMBER)*
+
+**context:** transform handler for request
+
+**description**: This function can be used to set the total bytes to be sent to the upstream.
+
+This function should be called before any real data is returned from the transform handler.
+
+
 :ref:`TOP <admin-plugins-ts-lua>`
 
 ts.http.skip_remapping_set

example/plugins/lua-api/reqbody.lua

@@ -14,9 +14,22 @@
 --  See the License for the specific language governing permissions and
 --  limitations under the License.
 
-function encrypt(data, eos)
+-- This example illustrates how to do request body transform.
+-- It stores the request body and prints it at the end of the transform.
+
+function request_transform(data, eos)
   ts.ctx['reqbody'] = ts.ctx['reqbody'] .. data
 
+  if ts.ctx['len_set'] == nil then
+    ts.debug("len not set")
+    local sz = ts.http.req_transform.get_downstream_bytes()
+    ts.debug("len "..sz)
+    ts.http.req_transform.set_upstream_bytes(sz)
+    ts.ctx['len_set'] = true
+  end
+
+  ts.debug("req transform got " .. string.len(data) .. "bytes, eos=" .. eos)
+
   if (eos == 1) then
     ts.debug('End of Stream and the reqbody is ... ')
     ts.debug(ts.ctx['reqbody'])
@@ -29,7 +42,7 @@ function do_remap()
   ts.debug('do_remap')
   if (ts.client_request.get_method() == 'POST') then
     ts.ctx['reqbody'] = ''
-    ts.hook(TS_LUA_REQUEST_TRANSFORM, encrypt)
+    ts.hook(TS_LUA_REQUEST_TRANSFORM, request_transform)
   end
 
   return 0

plugins/lua/ts_lua_http.c

@@ -113,6 +113,12 @@ static int ts_lua_http_resp_transform_get_upstream_watermark_bytes(lua_State *L)
 static int ts_lua_http_resp_transform_set_upstream_watermark_bytes(lua_State *L);
 static int ts_lua_http_resp_transform_set_downstream_bytes(lua_State *L);
 
+static void ts_lua_inject_http_req_transform_api(lua_State *L);
+static int ts_lua_http_req_transform_get_downstream_bytes(lua_State *L);
+static int ts_lua_http_req_transform_get_downstream_watermark_bytes(lua_State *L);
+static int ts_lua_http_req_transform_set_downstream_watermark_bytes(lua_State *L);
+static int ts_lua_http_req_transform_set_upstream_bytes(lua_State *L);
+
 void
 ts_lua_inject_http_api(lua_State *L)
 {
@@ -196,6 +202,11 @@ ts_lua_inject_http_transform_api(lua_State *L)
   lua_newtable(L);
   ts_lua_inject_http_resp_transform_api(L);
   lua_setfield(L, -2, "resp_transform");
+
+  /*  ts.http.req_transform api */
+  lua_newtable(L);
+  ts_lua_inject_http_req_transform_api(L);
+  lua_setfield(L, -2, "req_transform");
 }
 
 static void
@@ -214,6 +225,22 @@ ts_lua_inject_http_resp_transform_api(lua_State *L)
   lua_setfield(L, -2, "set_downstream_bytes");
 }
 
+static void
+ts_lua_inject_http_req_transform_api(lua_State *L)
+{
+  lua_pushcfunction(L, ts_lua_http_req_transform_get_downstream_bytes);
+  lua_setfield(L, -2, "get_downstream_bytes");
+
+  lua_pushcfunction(L, ts_lua_http_req_transform_get_downstream_watermark_bytes);
+  lua_setfield(L, -2, "get_downstream_watermark_bytes");
+
+  lua_pushcfunction(L, ts_lua_http_req_transform_set_downstream_watermark_bytes);
+  lua_setfield(L, -2, "set_downstream_watermark_bytes");
+
+  lua_pushcfunction(L, ts_lua_http_req_transform_set_upstream_bytes);
+  lua_setfield(L, -2, "set_upstream_bytes");
+}
+
 static void
 ts_lua_inject_http_misc_api(lua_State *L)
 {
@@ -1010,3 +1037,30 @@ ts_lua_http_resp_transform_set_downstream_bytes(lua_State *L)
 
   return 0;
 }
+
+// Request transform are similar to response transform. It works against the transform context available.
+// We can get the downstream bytes and set the upstream bytes.
+// We can also get and set the downstream watermark as well.
+static int
+ts_lua_http_req_transform_get_downstream_bytes(lua_State *L)
+{
+  return ts_lua_http_resp_transform_get_upstream_bytes(L);
+}
+
+static int
+ts_lua_http_req_transform_get_downstream_watermark_bytes(lua_State *L)
+{
+  return ts_lua_http_resp_transform_get_upstream_watermark_bytes(L);
+}
+
+static int
+ts_lua_http_req_transform_set_downstream_watermark_bytes(lua_State *L)
+{
+  return ts_lua_http_resp_transform_set_upstream_watermark_bytes(L);
+}
+
+static int
+ts_lua_http_req_transform_set_upstream_bytes(lua_State *L)
+{
+  return ts_lua_http_resp_transform_set_downstream_bytes(L);
+}