This is against:
https://git.opendaylight.org/gerrit/#/c/3314/10 (controller side)

https://git.opendaylight.org/gerrit/#/c/3451/2 (openflowplugin side)

Build the controller
Build openflowplugin using -nsu

Run distribution/base/target/../run.sh -debug

Connect a mininet-2.1.0-of1.3 switch

From the OSGI console run

addMDFlow openflow:1 f1

Confirm this results in a flow on the switch:

sudo ovs-ofctl -O OpenFlow13 dump-flows s1

With POSTMAN

GET: http://192.168.195.157:8080/restconf/config/opendaylight-inventory:nodes/node/openflow:1/table/2/

Accept: application/xml

You should get back:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<table
xmlns="urn:opendaylight:flow:inventory">
<flow>
<strict>false</strict>
<instructions>
<instruction>
<apply-actions>
<action>
<dec-nw-ttl/>
</action>
</apply-actions>
</instruction>
</instructions>
<table_id>2</table_id>
<id>124</id>
<cookie_mask>10</cookie_mask>
<out_port>10</out_port>
<installHw>false</installHw>
<out_group>2</out_group>
<match>
<ethernet-match>
<ethernet-type>
<type>2048</type>
</ethernet-type>
</ethernet-match>
<ipv4-destination>10.0.0.1/24</ipv4-destination>
</match>
<hard-timeout>12</hard-timeout>
<cookie>10</cookie>
<idle-timeout>34</idle-timeout>
<flow-name>FooXf1</flow-name>
<priority>2</priority>
<barrier>false</barrier>
</flow>
</table>

But when you try to address the flow directly with:

http://192.168.195.157:8080/restconf/config/opendaylight-inventory:nodes/node/openflow:1/table/2/flow/124

You will get a 404 "No data exists"