The chain_api_plugin exposes functionality from the chain_plugin to the RPC API interface managed by the http_plugin.
# config.ini
plugin = eosio::chain_api_plugin# command-line
nodeos ... --plugin eosio::chain_api_pluginNone
# config.ini
plugin = eosio::chain_plugin
[options]
plugin = eosio::http_plugin
[options]# command-line
nodeos ... --plugin eosio::chain_plugin [operations] [options] \
--plugin eosio::http_plugin [options]