Added plugin documentation (#248)

guides/plugins_and_handlers.md → guides/handlers.md

@@ -1,13 +1,8 @@
-# Plugins and handlers
+# Handlers
 
 ## Handlers
 
 Handlers are a nifty thing that is called on when the controller returns. For example if the controller returns
 `{json, #{hello => world}}` we would like Nova to create a proper JSON response to the requester. That means setting correct
 headers, encode the payload and send it out. This is what _handlers_ are for. They are (often short) functions that transforms something like
 `{json, Payload}` to proper output.
-
-## Plugins
-
-Plugins are a bit like the handlers except they are run on request. There's currently two different type of plugins; `pre_request` and `post_request`.
-These can be used to create access logs, insert CORS headers or similar.

guides/nova-pubsub.md

@@ -1,6 +1,6 @@
 # Nova Pubsub
 
-With version 0.9.4 we introduced the concept of a pubsub-like mechanism in Nova so that users can build distributed services. Internally it relies on Erlangs `pg2`-module which enables distributed named process groups. The concept is really simple and there's not much depth in the current implementation - it should only be used as a simple message bus. If you need more advanced features please take a look at [RabbitMQ](rabbitmq) or [MQTT](https://mqtt.org).
+With version 0.9.4 we introduced the concept of a pubsub-like mechanism in Nova so that users can build distributed services. Internally it relies on Erlangs `pg2`-module which enables distributed named process groups. The concept is really simple and there's not much depth in the current implementation - it should only be used as a simple message bus. If you need more advanced features please take a look at [RabbitMQ](https://www.rabbitmq.com/) or [MQTT](https://mqtt.org).
 
 ## Basic concepts
 

guides/plugins.md

@@ -1,5 +1,8 @@
 # Plugins
 
+Plugins are a bit like the handlers except they are run on request. There's currently two different type of plugins; `pre_request` and `post_request`.
+These can be used to create access logs, insert CORS headers or similar.
+
 Plugins are used to handle things before and/or after a request. They are applied on all requests of a specified protocol.
 
 This is an example:
@@ -67,3 +70,54 @@ increment(#{<<"json">> := #{<<"id">> := Id, <<"value">> := Value}})->
     {json,200,#{},#{<<"id">> => Id , <<"received">> => Value, <<"increment">> => Value+1}}.
 
 ```
+## Nova plugins
+
+Nova has a couple of plugins for some general purposes.
+
+|Plugin|Description|Code|
+|nova_correlation_plugin|This plugin will add a correlation id to header response but also add `#{correlation_id => CorrelationID}` to the request obj that is passed to the controller.|[nova_correlation_plugin](https://github.com/novaframework/nova/blob/master/src/plugins/nova_correlation_plugin.erl)|
+|nova_cors_plugin|This plugin will handle cors and add the cors headers into the request.|[nova_cors_plugin](https://github.com/novaframework/nova/blob/master/src/plugins/nova_cors_plugin.erl)|
+|nova_request_plugin|This plugin will handle incomming data like qs, form urlencoded and json|[nova_request_plugin](https://github.com/novaframework/nova/blob/master/src/plugins/nova_request_plugin.erl)|
+
+
+### Nova correlation
+
+This plugin will generate a uuid v4 and set it as a response header as `X-Correlation-ID` if nothing is configuered.
+
+```erlang
+{pre_request; nova_correlation_plugin, #{request_correlation_header => CorrelationHeader,
+                                         logger_metadata_key => LoggerMetaDataKey}}
+```
+
+|Option|Description|
+|request_correlation_header|This is if you want a different correlation header than the standard `X-Correlation-ID`|
+|logger_metadata_key| This is if you want to have a different metadata key then the standard `correaltion_id`|
+
+### Nova cors
+
+This plugins will make it so that if we get method OPTIONS it will just return back the CORS headers. In this case you don't need a controller to handle it and the plugin stops after this.
+For other methods it will add the CORS headers to the request.
+
+```erlang
+{pre_request; nova_cors_plugin, #{allow_origins => <<"*">>}}
+```
+
+|Option|Description|
+|allow_origins|Specifies which origins to insert into Access-Control-Allow-Origin|
+
+### Nova request
+
+This plugins handle incoming data and can transform them to erlang maps depending on what the options are.
+
+```erlang
+{pre_request; nova_correlation_plugin, #{decode_json_body => true,
+                                         read_urlencoded_body => true,
+                                         parse_qs => true|list}}
+```
+
+
+|Option|Description|Req|
+|decode_json_body|If header is application/json it will decode the body.| `Req#{json => Map}`|
+|read_urlencoded_body|If header is application/x-www-form-urlencoded it will decode it.| `Req#{params => Map}`|
+|parse_qs| If the path have qs in it we will get them.|`Req#{parsed_qs => Map or List}`|
+

rebar.config

@@ -117,10 +117,10 @@
                     <<"guides/routing.md">>,
                     <<"guides/controllers.md">>,
                     <<"guides/views.md">>,
-                    <<"guides/plugins_and_handlers.md">>,
+                    <<"guides/handlers.md">>,
+                    <<"guides/plugins.md">>,
                     <<"guides/building-releases.md">>,
                     <<"guides/books-and-links.md">>,
-                    <<"guides/plugins.md">>,
                     <<"guides/rebar3_nova.md">>,
                     <<"guides/nova-pubsub.md">>]},
           {source_url, <<"https://github.com/novaframework/nova">>}

src/nova_watcher.erl

@@ -151,7 +151,7 @@ handle_cast(_Request, State) ->
                          {noreply, NewState :: term(), Timeout :: timeout()} |
                          {noreply, NewState :: term(), hibernate} |
                          {stop, Reason :: normal | term(), NewState :: term()}.
-handle_info({ProcessRef, {data, Data}}, State) ->
+handle_info({_ProcessRef, {data, Data}}, State) ->
     Msg = case Data of
               {eol, Text} -> Text;
               _ -> Data