Merge lp:~awuerl/txjsonrpc/preserve_result into lp:txjsonrpc

[Andreas Würl]

The current implementation does not allow to cache deferred results in a simple object cache. The result of any deferred is set to None after the rendering callback web.JSONRPC._cbRender() is called. As _cbRender returns nothing, the original value is discarded.

This minimal patch fixes this behaviour. Deferreds can now be stored/cached and returned multiple times. The original result will always be available to the caller of the service method.

[lp:~awuerl/txjsonrpc/preserve_result]

97. By Andreas Würl on 2014-08-14

added test

Unmerged revisions

97. By Andreas Würl on 2014-08-14

added test

96. By Andreas Würl on 2014-08-14

preserve result of deferred

=== modified file 'txjsonrpc/web/jsonrpc.py'
--- txjsonrpc/web/jsonrpc.py	2014-02-18 13:29:40 +0000
+++ txjsonrpc/web/jsonrpc.py	2014-08-14 18:55:54 +0000
@@ -115,6 +115,8 @@
         return server.NOT_DONE_YET
 
     def _cbRender(self, result, request, id, version):
+        original_result = result
+
         if isinstance(result, Handler):
             result = result.result
         if version == jsonrpclib.VERSION_PRE1:
@@ -133,6 +135,8 @@
         request.write(s)
         request.finish()
 
+        return original_result
+
     def _ebRender(self, failure, id):
         if isinstance(failure.value, jsonrpclib.Fault):
             return failure.value

=== modified file 'txjsonrpc/web/test/test_jsonrpc.py'
--- txjsonrpc/web/test/test_jsonrpc.py	2012-01-28 01:11:15 +0000
+++ txjsonrpc/web/test/test_jsonrpc.py	2014-08-14 18:55:54 +0000
@@ -26,6 +26,11 @@
     NOT_FOUND = jsonrpclib.METHOD_NOT_FOUND
     SESSION_EXPIRED = 42
 
+    def __init__(self):
+        jsonrpc.JSONRPC.__init__(self)
+        self.cached_deferred = None
+
+
     def jsonrpc_add(self, a, b):
         """
         This function add two numbers.
@@ -52,6 +57,11 @@
         # The doc string is part of the test.
         return defer.succeed(x)
 
+    def jsonrpc_deferCached(self, x):
+        if self.cached_deferred is None:
+            self.cached_deferred = defer.succeed(x)
+        return self.cached_deferred
+
     def jsonrpc_deferFail(self):
         return defer.fail(TestValueError())
 
@@ -121,6 +131,8 @@
         return [
             5,
             "a",
+            "a",
+            "a",
             1,
             ["a", 1],
             "null",
@@ -130,6 +142,8 @@
         input = [
             ("add", (2, 3)),
             ("defer", ("a",)),
+            ("deferCached", ("a",)),
+            ("deferCached", ("b",)),
             ("dict", ({"a": 1}, "a")),
             ("pair", ("a", 1)),
             ("none", ()),
@@ -173,7 +187,7 @@
             meths.sort()
             self.failUnlessEqual(
                 meths,
-                ['add', 'complex', 'defer', 'deferFail',
+                ['add', 'complex', 'defer', 'deferCached', 'deferFail',
                  'deferFault', 'dict', 'fail', 'fault',
                  'none', 'pair', 'system.listMethods',
                  'system.methodHelp',