Mas i1847 conditionalput (#86) (#87)

Add support for `if_not_modified` option, which should work as with riak-erlang-client (and use the X-Riak-If-Not-Modified) header in Riak 3.0.13.

Add support for using `if_none_match`, and `if_match`.  However, if possible, `if_not_modified` should always in preference to `if_match` as `if_match` requires re-calculation of the etag, using knowledge that should be internal to Riak.

Author: martinsumner

include/raw_http.hrl

@@ -38,6 +38,7 @@
 -define(HEAD_CLIENT,          "X-Riak-ClientId").
 -define(HEAD_USERMETA_PREFIX, "x-riak-meta-").
 -define(HEAD_INDEX_PREFIX,    "X-Riak-Index-").
+-define(HEAD_IF_NOT_MODIFIED, "X-Riak-If-Not-Modified").
 
 %%======================================================================
 %% JSON keys/values

src/rhc.erl

@@ -866,8 +866,9 @@ put(Rhc, Object, Options) ->
                 true              -> put
              end,
     {Headers0, Body} = rhc_obj:serialize_riakc_obj(Rhc, Object),
-    Headers = [{?HEAD_CLIENT, client_id(Rhc, Options)}
-               |Headers0],
+    PutHeaders = conditional_put_headers(Options, Object),
+    Headers = 
+        [{?HEAD_CLIENT, client_id(Rhc, Options)} |Headers0] ++ PutHeaders,
     case request(Method, Url, ["200", "204", "300"], Headers, Body, Rhc) of
         {ok, Status, ReplyHeaders, ReplyBody} ->
             if Status =:= "204" ->
@@ -1893,6 +1894,32 @@ get_ssl_options(Options) ->
             []
     end.
 
+conditional_put_headers(Options, Object) ->
+    NoneMatch =
+        case lists:member(if_none_match, Options) of
+            true ->
+                [{"If-None-Match", "*"}];
+            false ->
+                []
+        end,
+    Match =
+        case lists:member(if_match, Options) of
+            true ->
+                VTag = riakc_obj:get_vtag(Object),
+                [{"If-Match", VTag}];
+            false ->
+                []
+        end,
+    NotModified =
+        case lists:member(if_not_modified, Options) of
+            true ->
+                VC = base64:encode(riakc_obj:vclock(Object)),
+                [{?HEAD_IF_NOT_MODIFIED, VC}];
+            false ->
+                []
+        end,
+    NoneMatch ++ Match ++ NotModified.
+
 extract_bucket_type({<<"default">>, B}) ->
     {undefined, B};
 extract_bucket_type({T,B}) ->