# An Ocpp Model
[](https://codecov.io/gh/gertjana/ocpp_model)
[](https://travis-ci.com/gertjana/ocpp_model)
Currently I'm running 2 experiments
- An Ocpp Backend in Elixir
- A Nerves based Charger on a Rasberry Pi Zero
This library contains the OCPP 2.x Model / Protocol that is needed for both those projects
It will be populated on a 'need to have' basis starting with basic charger functionality
## Implemented Messages
`C=Charger, CS=ChargeSystem, arrow Message Direction`
### OCPP 2.0.1
- `C->CS AuthorizeRequest/Response`
- `C->CS BootNoficationRequest/Response`
- `C<-CS ChangeAvailabilityRequest/Response`
- `C<>CS DataTransferRequest/Response`
- `C->CS HeartbeatRequest/Response`
- `C->CS StatusNotificationRequest/Response`
- `C->CS TransationEventRequest/Response`
- `C<-CS UnlockConnectorRequest/Response`
## Installation
```elixir
def deps do
[
{:ocpp_model, "~> 0.1.0"}
]
end
```
## Usage
Using the library is by having your module assume either the `OcppModel.V20.Behaviours.Charger` or the `OcppModel.V20.Behaviours.ChargeSystem` Behaviour.
This library does not make any decisions on transport, you can the json over websockets thing, or protobuf over http long-polling
or an IoT solution as long as it supports bi-directional communication
```bash
+---------------+ +----------------+ Internet +----------------+ +--------------------+
| MyTestCharger | <-> | json/websocket | <- Lora -> | websocket/json | <-> | MyTestChargeSystem |
+---------------+ +----------------+ IoT +----------------+ +--------------------+
\----------------------------------------------------------/
Implement yourself
```
## An example Charger
```
defmodule MyTestCharger do
alias OcppModel.V20.Behaviours, as: B
alias OcppModel.V20.EnumTypes, as: ET
alias OcppModel.V20.FieldTypes, as: FT
alias OcppModel.V20.Messages, as: M
@behaviour B.Charger
def handle([2, id, action, payload]) do
case B.Charger.handle(MyTestCharger, action, payload) do
{:ok, response_payload} -> [3, id, response_payload]
{:error, error} -> [4, id, Atom.to_string(error), "", {}]
end
end
def handle([3, id, payload]), do: IO.puts "Received answer for id #{id}: #{inspect(payload)}"
def handle([4, id, err, desc, det]), do: IO.puts "Received error for id #{id}: #{err}, #{desc}, #{det}"
@impl B.Charger
def change_availability(req) do
if ET.validate?(:operationalStatusEnumType, req.operationalStatus) do
{:ok, %M.ChangeAvailabilityResponse{status: "Accepted",
statusInfo: %FT.StatusInfoType{reasonCode: "charger is inoperative"}}}
else
{:error, :invalid_operational_status}
end
end
@impl B.Charger
def data_transfer(_req), do: {:ok, %M.DataTransferResponse{status: "Accepted"}}
@impl B.Charger
def unlock_connector(_req), do:
{:ok, %M.UnlockConnectorResponse{status: "Unlocked",
statusInfo: %FT.StatusInfoType{reasonCode: "cable unlocked"}}}
end
```
## An Example ChargeSystem
```
defmodule MyTestChargeSystem do
alias OcppModel.V20.Behaviours, as: B
alias OcppModel.V20.EnumTypes, as: ET
alias OcppModel.V20.FieldTypes, as: FT
alias OcppModel.V20.Messages, as: M
@behaviour B.ChargeSystem
def handle([2, id, action, payload]) do
case B.ChargeSystem.handle(__MODULE__, action, payload) do
{:ok, response_payload} -> [3, id, response_payload]
{:error, error} -> [4, id, Atom.to_string(error), "", {}]
end
end
def handle([3, id, payload]), do: IO.puts "Received answer for id #{id}: #{inspect(payload)}"
def handle([4, id, err, desc, det]), do: IO.puts "Received error for id #{id}: #{err}, #{desc}, #{det}"
@impl B.ChargeSystem
def authorize(_req) do
{:ok, %M.AuthorizeResponse{idTokenInfo: %FT.IdTokenInfoType{status: "Accepted"}}}
end
@impl B.ChargeSystem
def boot_notification(req) do
if ET.validate?(:bootReasonEnumType, req.reason) do
{:ok, %M.BootNotificationResponse{currentTime: current_time(), interval: 900,
status: %FT.StatusInfoType{reasonCode: ""}}}
else
{:error, :invalid_bootreason}
end
end
@impl B.ChargeSystem
def data_transfer(req) do
case req.vendorId do
"GA" -> {:ok, %M.DataTransferResponse{status: "Accepted", data: String.reverse(req.data)}}
_ -> {:ok, %M.DataTransferResponse{status: "UnknownVendorId"}}
end
end
@impl B.ChargeSystem
def heartbeat(_req) do
{:ok, %M.HeartbeatResponse{currentTime: current_time()}}
end
@impl B.ChargeSystem
def status_notification(_req) do
{:ok, %M.StatusNotificationResponse{}}
end
@impl B.ChargeSystem
def transaction_event(_req) do
{:ok, %M.TransactionEventResponse{}}
end
def current_time, do: DateTime.now!("Etc/UTC") |> DateTime.to_iso8601()
end
```
