[multiplexer] option to skip post/put requests

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

@@ -24,7 +24,8 @@
 
 |Name| is a remap plug-in that allows a request to be multiplexed one or more times and sent to
 different remap entries. Both headers and body (in case of POST or PUT methods, only) are copied
-into the new requests.
+into the new requests. Optionally POST/PUT requests can be skipped via
+``pparam=proxy.config.multiplexer.skip_post_put=1``.
 
 Description
 ===========
@@ -59,6 +60,7 @@ Example remap.config::
     map http://www.example.com/a http://www.example.com/ @plugin=multiplexer.so @pparam=host1.example.com
     map http://www.example.com/b http://www.example.com/ @plugin=multiplexer.so @pparam=host2.example.com
     map http://www.example.com/c http://www.example.com/ @plugin=multiplexer.so @pparam=host1.example.com @pparam=host2.example.com
+    map http://www.example.com/d http://www.example.com/ @plugin=multiplexer.so @pparam=host1.example.com @pparam=host2.example.com @pparam=proxy.config.multiplexer.skip_post_put=1
 
 
 Implementation

plugins/multiplexer/ats-multiplexer.cc

@@ -74,11 +74,19 @@ TSReturnCode
 TSRemapNewInstance(int argc, char **argv, void **i, char *, int)
 {
   assert(i != nullptr);
-  Instance *instance = new Instance;
+  Instance *instance    = new Instance;
+  instance->skipPostPut = false;
 
   if (argc > 2) {
-    std::copy(argv + 2, argv + argc, std::back_inserter(instance->origins));
+    std::copy_if(argv + 2, argv + argc, std::back_inserter(instance->origins), [&](std::string s) {
+      if (s == "proxy.config.multiplexer.skip_post_put=1") {
+        instance->skipPostPut = true;
+        return false;
+      }
+      return true;
+    });
   }
+  TSDebug(PLUGIN_TAG, "skipPostPut is %s", (instance->skipPostPut ? "true" : "false"));
 
   *i = static_cast<void *>(instance);
 
@@ -109,41 +117,46 @@ DoRemap(const Instance &i, TSHttpTxn t)
   assert(buffer != nullptr);
   assert(location != nullptr);
 
-  {
-    TSMLoc field;
+  int length;
+  const char *const method = TSHttpHdrMethodGet(buffer, location, &length);
 
-    CHECK(TSMimeHdrFieldCreateNamed(buffer, location, "X-Multiplexer", 13, &field));
-    assert(field != nullptr);
+  TSDebug(PLUGIN_TAG, "Method is %s.", std::string(method, length).c_str());
 
-    CHECK(TSMimeHdrFieldValueStringSet(buffer, location, field, -1, "original", 8));
+  if (i.skipPostPut && ((length == TS_HTTP_LEN_POST && memcmp(TS_HTTP_METHOD_POST, method, TS_HTTP_LEN_POST) == 0) ||
+                        (length == TS_HTTP_LEN_PUT && memcmp(TS_HTTP_METHOD_PUT, method, TS_HTTP_LEN_PUT) == 0))) {
+    TSHandleMLocRelease(buffer, TS_NULL_MLOC, location);
+  } else {
+    {
+      TSMLoc field;
 
-    CHECK(TSMimeHdrFieldAppend(buffer, location, field));
+      CHECK(TSMimeHdrFieldCreateNamed(buffer, location, "X-Multiplexer", 13, &field));
+      assert(field != nullptr);
 
-    CHECK(TSHandleMLocRelease(buffer, location, field));
-  }
+      CHECK(TSMimeHdrFieldValueStringSet(buffer, location, field, -1, "original", 8));
 
-  Requests requests;
-  generateRequests(i.origins, buffer, location, requests);
-  assert(requests.size() == i.origins.size());
+      CHECK(TSMimeHdrFieldAppend(buffer, location, field));
 
-  int length;
-  const char *const method = TSHttpHdrMethodGet(buffer, location, &length);
-
-  TSDebug(PLUGIN_TAG, "Method is %s.", std::string(method, length).c_str());
+      CHECK(TSHandleMLocRelease(buffer, location, field));
+    }
 
-  if (length == TS_HTTP_LEN_POST && memcmp(TS_HTTP_METHOD_POST, method, TS_HTTP_LEN_POST) == 0) {
-    const TSVConn vconnection = TSTransformCreate(handlePost, t);
-    assert(vconnection != nullptr);
-    TSContDataSet(vconnection, new PostState(requests));
-    assert(requests.empty());
-    TSHttpTxnHookAdd(t, TS_HTTP_REQUEST_TRANSFORM_HOOK, vconnection);
-  } else {
-    dispatch(requests, timeout);
-  }
+    Requests requests;
+    generateRequests(i.origins, buffer, location, requests);
+    assert(requests.size() == i.origins.size());
+
+    if (length == TS_HTTP_LEN_POST && memcmp(TS_HTTP_METHOD_POST, method, TS_HTTP_LEN_POST) == 0) {
+      const TSVConn vconnection = TSTransformCreate(handlePost, t);
+      assert(vconnection != nullptr);
+      TSContDataSet(vconnection, new PostState(requests));
+      assert(requests.empty());
+      TSHttpTxnHookAdd(t, TS_HTTP_REQUEST_TRANSFORM_HOOK, vconnection);
+    } else {
+      dispatch(requests, timeout);
+    }
 
-  TSHandleMLocRelease(buffer, TS_NULL_MLOC, location);
+    TSHandleMLocRelease(buffer, TS_NULL_MLOC, location);
 
-  TSStatIntIncrement(statistics.requests, 1);
+    TSStatIntIncrement(statistics.requests, 1);
+  }
 }
 
 TSRemapStatus

plugins/multiplexer/dispatch.h

@@ -63,6 +63,7 @@ typedef std::vector<Request> Requests;
 
 struct Instance {
   Origins origins;
+  bool skipPostPut;
 };
 
 extern size_t timeout;