Add gateway node docu Co-authored-by: Jitpanu Maneeratpongsuk <jitpanu.maneeratpongsuk@rwth-aachen.de>

Signed-off-by: Alexandra <alexandra.bach@eonerc.rwth-aachen.de>

Author: al3xa23

docs/node/nodes/gateway.md

@@ -5,14 +5,14 @@ hide_table_of_contents: true
 
 # Gateway
 
-The `gateway` node-type enable VILLASnode to transform api type. 
+The `gateway` node-type enables VILLASnode to transform Application Programmable Interfaces (API) types. 
 Currently, the transformation of [http](https://en.wikipedia.org/wiki/HTTP) and [gRPC](https://grpc.io/) is supported. 
 
 
 ### Limitations
 
 - For protobuf payload that is not [VILLASnode format](../formats/protobuf.md), only simple datatypes are supported. 
-- It only supported unary RPC.
+- It only supportes unary RPC.
 
 
 ## Prerequisites
@@ -55,17 +55,20 @@ nodes = {
 ## Usage
 
 The usage of this node is similar to [`api`](api.md) node-type.
-The following [`curl`](https://curl.se/) commands are example for calling gRPC method with HTTP api.
-The input of gRPC method can be either by the body of http request or input data from other node(via a [path](../config/paths.md)).
+The following [`curl`](https://curl.se/) commands are examples for calling gRPC methods with http API.
+The input for a gRPC call can be either the body of http request or input data from another node (via a [path](../config/paths.md)).
 If the http request body is empty, the input from other node will be used.
 
+Since this node-type does not implement the gRPC server, it needs to be added manually. A description is available [here](https://www.acs.eonerc.rwth-aachen.de/global/show_document.asp?id=aaaaaaaadidaesd).
+
 Note on http methods
  - GET should be used only when the input of gRPC method can be empty or ignored.
  - PUT should be used when the output of gRPC method is in VILLASnode format and the user want to put the data to the path.
  - POST should be used when the output of gRPC method is not in VILLASnode format or the user not want output data to the path.
 
 
-#### The url for sending a request to this node-type are as following
+### General Request
+The url for sending a request to the gateway node-type is as following:
 ```
 http://<address>:<port>/api/v2/gateway/<node name or UUID>/<gRPC package>/<gRPC service>/<gRPC method>
 ```
@@ -94,23 +97,23 @@ message msg {
 
 ```
 
-#### Call GetData method on gRPC server
+### Call GetData method on gRPC server
 
 ```shell
 curl http://localhost:8080/api/v2/gateway/gateway_node/ex_server/ex_service/GetData -XPUT
 ```
 Since the PUT method is used, the output from gRPC method will be put to the path.
 
-#### Call SetData method on gRPC server
+### Call SetData method on gRPC server
 
 ```shell
 curl http://localhost:8080/api/v2/gateway/gateway_node/ex_server/ex_service/SetData -XPOST
 ```
 Since the body is empty the data from the path will be send to gRPC server.
 
-#### Call GetDataRef method on gRPC server
+### Call GetDataRef method on gRPC server
 
 ```shell
 curl http://localhost:8080/api/v2/gateway/gateway_node/ex_server/ex_service/GetDataRef -d '{"ref":[0,1,2,3,4]}'
 ```
-Since the body is not empty, it will be form into protobuf payload based on the example `.proto` file and send to the gRPC server.
+Since the body is not empty, it will a protobuf payload based on the example `.proto` file and send to the gRPC server.

docs/node/nodes/index.md

@@ -27,6 +27,7 @@ VILLASnode currently supports the following node-types:
 | [exec](exec.md)                     | no                | yes  | yes   | unlimited | stable      | |
 | [file](file.md)                     | no                | yes  | yes   | unlimited | stable      | |
 | [fpga](fpga.md)                     | no                | yes  | yes   | ?         | beta        | |
+| [gateway](gateway.md)               | no                | yes  | yes   | unlimited | stable      | HTTP to gRPC conversion only |
 | [iec60870-5-104](iec60870-5-104.md) | no                | no   | yes   | 1         | stable      | |
 | [iec61850-8-1](iec61850-8-1.md)     | no                | yes  | yes   | 1         | alpha       | |
 | [iec61850-9-2](iec61850-9-2.md)     | no                | yes  | yes   | 1         | beta        | |