# An Ocpp Model
[](https://codecov.io/gh/gertjana/ocpp_model)
[](https://gitlab.com/gertjana/ocpp_model)
[](https://hex.pm/packages/ocpp_model)
Currently I'm doing 2 experiments
- An Ocpp Backend in Elixir
- A Nerves based Charger on a Rasberry Pi Zero
This library contains the OCPP 2.0.1 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
| OCPP Version | State | Done-ness |
| ------------ | -------------------------------------- | --------- |
| 2.0.1 | [messages_2.0.1.md](messages_2.0.1.md) | 81% |
| 1.6 | [messages_1.6.md](messages_1.6.md) | 0% |
## Add Dependency
```elixir
def deps do
[
{:ocpp_model, "~> 0.2.5"}
]
end
```
## Usage
Using the library is by having your modules assume either the of the following behaviours:
| Behaviour | Summary |
| -------------------------------------------- | --------------------------------------------------------------- |
| `OcppModel.V20.Behaviours.BasicCharger` | Supports callbacke for only the basic messages |
| `OcppModel.V20.Behaviours.Charger` | Supports callbacks for all messages implemented in this library |
| `OcppModel.V20.Behaviours.BasicChargeSystem` | Supports callbacks for only the basic messages |
| `OcppModel.V20.Behaviours.ChargeSystem` | Supports callbacks for all messages implemented in this library |
This library does not make any decisions on transport, you can do the json over websockets thing, or protobuf over http long-polling
or an IoT solution as long as it supports bi-directional communication
```bash
+-------------------+ +------------+ +------------------------+
| Charger Behaviour | | OCPP Model | | ChargeSystem Behaviour |
+-------------------+ +------------+ +------------------------+
| | | |
| +--------------------------------+ +--------------------------------+ |
| | | |
V V V V
+---------------+ +----------------+ Internet +----------------+ +--------------------+
| MyTestCharger | <-> | json/websocket | <- Lora -> | websocket/json | <-> | MyTestChargeSystem |
+---------------+ +----------------+ IoT +----------------+ +--------------------+
```
## An example Charger
```elixir
defmodule Implementations.MyBasicCharger do
@moduledoc """
Basic charger implementation, only supports the minimum required to do a chargesession.
"""
alias OcppModel.V20.Behaviours, as: B
alias OcppModel.V20.DataTypes, as: DT
alias OcppModel.V20.EnumTypes, as: ET
alias OcppModel.V20.Messages, as: M
@behaviour B.BasicCharger
def handle([2, id, action, payload]) do
case B.BasicCharger.handle(__MODULE__, action, payload) do
{:ok, response_payload} -> [3, id, response_payload]
{:error, error, desc} -> [4, id, Atom.to_string(error), desc, {}]
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.BasicCharger
def reset(req) do
if ET.validate?(:reset, req.type) do
case req.type do
"Immediate" -> {:ok, %M.ResetResponse{status: "Accepted"}}
"OnIdle" -> {:ok, %M.ResetResponse{status: "Scheduled"}}
end
else
{:error, "Unknown Reset Type #{req.type}"}
end
end
@impl B.BasicCharger
def unlock_connector(_req), do:
{:ok, %M.UnlockConnectorResponse{status: "Unlocked",
statusInfo: %DT.StatusInfo{reasonCode: "cable unlocked"}}}
end
```
## An Example ChargeSystem
```elixir
defmodule Implementations.MyBasicChargeSystem do
@moduledoc """
Basic chargesystem implementation, only supports the minimum required to do a chargesession.
"""
alias OcppModel.V20.Behaviours, as: B
alias OcppModel.V20.DataTypes, as: DT
alias OcppModel.V20.EnumTypes, as: ET
alias OcppModel.V20.Messages, as: M
@behaviour B.BasicChargeSystem
def handle([2, id, action, payload]) do
case B.BasicChargeSystem.handle(__MODULE__, action, payload) do
{:ok, response_payload} -> [3, id, response_payload]
{:error, error, desc} -> [4, id, Atom.to_string(error), desc, {}]
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.BasicChargeSystem
def authorize(_req) do
{:ok, %M.AuthorizeResponse{idTokenInfo: %DT.IdTokenInfo{status: "Accepted"}}}
end
@impl B.BasicChargeSystem
def boot_notification(req) do
if ET.validate?(:bootReason, req.reason) do
{:ok, %M.BootNotificationResponse{currentTime: current_time(), interval: 900,
status: %DT.StatusInfo{reasonCode: ""}}}
else
{:error, :invalid_bootreason, "#{req.reason} is not a valid BootReason"}
end
end
@impl B.BasicChargeSystem
def heartbeat(_req) do
{:ok, %M.HeartbeatResponse{currentTime: current_time()}}
end
@impl B.BasicChargeSystem
def status_notification(_req) do
{:ok, %M.StatusNotificationResponse{}}
end
@impl B.BasicChargeSystem
def transaction_event(_req) do
{:ok, %M.TransactionEventResponse{}}
end
def current_time, do: DateTime.now!("Etc/UTC") |> DateTime.to_iso8601()
end
```
