This is a C++ library implementation of OCPP for version 1.6 (https://www.openchargealliance.org/protocols/ocpp-16/) and 2.0.1 (https://www.openchargealliance.org/protocols/ocpp-201/). It enables charging stations to communicate with cloud backends for remote control, monitoring and billing of charging processes.
Libocpp can be used for the communication of one charging station and multiple EVSE using a single websocket connection.
Libocpp provides a complete implementation of OCPP 1.6. The implementation of OCPP 2.0.1 is currently under development.
- C++ implementation of OCPP
- Table of contents
- Feature Support
- CSMS Compatibility
- Integration with EVerest
- Integrate this library with your Charging Station Implementation for OCPP1.6
- Overview of the required callbacks and events and what libocpp expects to happen
- ChargePoint() constructor
- registering callbacks
- Functions that need to be triggered from the outside after new information is availble (on_... functions in the charge point API)
- The following functions are triggered depending on different so called "Session Events" from the EvseManager
- Authorization
- Overview of the required callbacks and events and what libocpp expects to happen
- Integrate this library with your Charging Station Implementation for OCPP2.0.1
- Install libocpp
- Quickstart for OCPP 1.6
- Building the doxygen documentation
- Unit testing
- Building with FetchContent instead of EDM
The following tables show the current support for the listed feature profiles / functional blocks and application notes.
All documentation and the issue tracking can be found in our main repository here: https://github.com/EVerest/
Feature Profile | Supported |
---|---|
Core | ✔️ yes |
Firmware Management | ✔️ yes |
Local Auth List Management | ✔️ yes |
Reservation | ✔️ yes |
Smart Charging | ✔️ yes |
Remote Trigger | ✔️ yes |
Whitepapers | Supported |
---|---|
OCPP 1.6 Security Whitepaper (3rd edition) | ✔️ yes |
Using ISO 15118 Plug & Charge with OCPP 1.6 | ✔️ yes |
The development of OCPP2.0.1 has already started and is in progress. See also the general roadmap of EVerest: https://github.com/EVerest/EVerest/blob/main/tsc/ROADMAP.md
The following table shows CSMS with which this library was tested. If you provide a CSMS that is not yet listed here, feel free to contact us!
- chargecloud
- chargeIQ
- Chargetic
- Compleo
- Current
- Daimler Truck
- ev.energy
- eDRV
- Fastned
- GraphDefined
- Electrip Global
- EV-Meter
- Green Motion
- gridundco
- ihomer
- iLumen
- EnergyStacks
- Siemens
- SteVe
- Syntech
- Trialog
- ubitricity
- Weev Energy
The current, basic implementation of OCPP 2.0.1 has been tested against a few CSMS and is continously tested against the OCPP Compliance Test Tool 2 (OCTT2) during the implementation.
This library is automatically integrated as the OCPP and OCPP201 module within everest-core - the complete software stack for your charging station. It is recommended to use EVerest together with this OCPP implementation.
If you run libocpp with OCPP1.6 with EVerest, the build process of everest-core will take care of installing all necessary dependencies for you.
the build process of everest-core will take care of installing all necessary dependencies for you. Additionally for OCPP2.0.1 you need to set up the SQLite device model storage database.
cd config/v201
python3 init_device_model_db.py
python3 insert_device_model_config.py --config config.json --db /tmp/ocpp201/device_model_storage.db
These two scripts do the following:
- create the database and tables and it will
- insert the variables with a role standardized within the OCPP2.0.1 specification
- insert the VariableAttributes specified within the config.json
OCPP is a protocol that affects, controls and monitors many areas of a charging station's operation.
If you want to integrate this library with your charging station implementation, you have to register a couple of callbacks and integrate event handlers. This is necessary for the library to interact with your charging station according to the requirements of OCPP.
Libocpp needs registered callbacks in order to execute control commands defined within OCPP (e.g Reset.req or RemoteStartTransaction.req)
The implementation must call event handlers of libocpp so that the library can track the state of the charging station and trigger OCPP messages accordingly (e.g. MeterValues.req , StatusNotification.req)
Your reference within libocpp to interact is a single instance to the class ChargePoint for OCPP 1.6 or to the class ChargePoint for OCPP 2.0.1.
The following section will give you a high level overview of how to integrate libocpp with your application. Please use the Doxygen Documentation as an additional source for the ChargePoint API.
In EVerest the OCPP module leverages several other modules to perform tasks that relate to authorization, reservations, charging session handling and system tasks like rebooting or firmware updates.
- Auth orchestrates authorization, utilizing different token providers like RFID reads and token validators. Libocpp mainly acts as a token validator, but in the case of RemoteStartTransactions it acts as a token provider as well
- EvseManager manages the charging session and charging state machine by communicating with a "board support package", a driver for the charging hardware that abstracts away the control pilot, relay control, power meters, etc. The EvseManager also handles reservations.
- System handles firmware updates, log uploads and resets
The following sections explain the steps you can follow to implement their functionality on your own and integrate the libocpp directly into your charging station software without relying on EVerest. However, in most cases it's much easier to write an EVerest driver using the everest-core/interfaces/board_support_AC.yaml interface.
The main entrypoint for libocpp for OCPP1.6 is the ocpp::v16::ChargePoint constructor. This is defined in libocpp/include/ocpp/v16/charge_point.hpp and takes the following parameters:
-
config: a std::string that contains the libocpp 1.6 config. There are example configs that work with a SteVe installation running in Docker, for example: config-docker.json
-
share_path: a std::filesystem path containing the path to the OCPP modules folder, for example pointing to /usr/share/everest/modules/OCPP. This path contains the following files and directories and is installed by the libocpp install target:
. ├── config-docker.json ├── config-docker-tls.json ├── config.json ├── init.sql ├── logging.ini └── profile_schemas ├── Config.json ├── Core.json ├── FirmwareManagement.json ├── Internal.json ├── LocalAuthListManagement.json ├── PnC.json ├── Reservation.json ├── Security.json └── SmartCharging.json
Here you can find:
-
the aforementioned config files
-
a logging.ini that is needed to initialize logging with Everest::Logging::init(path_to_logging_ini, "name_of_binary")
-
a init.sql file which contains the database schema used by libocpp for its sqlite database
-
and a profile_schemas directory. This contains json schema files that are used to validate the libocpp config. The schemas are split up according to the OCPP1.6 feature profiles like Core, FirmwareManagement and so on. Additionally there is a schema for "Internal" configuration options (for example the ChargePointId, or CentralSystemURI). A "PnC" schema for the ISO 15118 Plug & Charge with OCPP 1.6 Application note, as well as a "Security" schema for the OCPP 1.6 Security Whitepaper (3rd edition) are provided as well. Finally there's a Config.json schema that ties everything together
-
-
user_config_path: this points to a "user config", which we call a configuration file that's merged with the config that's provided in the "config" parameter. Here you can add, remove and overwrite settings without modifying the config passed in the first parameter directly. This is also used by libocpp to persistently modify config entries that are changed by the CSMS that should persist across restarts.
-
database_path: this points to the location of the sqlite database that libocpp uses to keep track of connector availability, the authorization cache and auth list, charging profiles and transaction data
-
sql_init_path: this points to the aforementioned init.sql file which contains the database schema used by libocpp for its sqlite database
-
message_log_path: this points to the directory in which libocpp can put OCPP communication logfiles for debugging purposes. This behavior can be controlled by the "LogMessages" (set to true by default) and "LogMessagesFormat" (set to ["log", "html", "session_logging"] by default, "console" and "console_detailed" are also available) configuration keys in the "Internal" section of the config file. Please note that this is intended for debugging purposes only as it logs all communication, including authentication messages.
-
certs_path: this points to the directory where certificates used by libocpp are located, these are used for the "Improved security for OCPP 1.6-J" whitepaper (e.g. Security Profile 3 TLS with Client Side Certificates) as well as for Plug & Charge.
The directory layout expected is as follows
. ├── ca │ ├── csms │ │ └── CSMS_ROOT_CA.pem │ ├── cso │ │ ├── CPO_CERT_CHAIN.pem │ │ ├── CPO_SUB_CA1_LEAF.der │ │ ├── CPO_SUB_CA1.pem │ │ ├── CPO_SUB_CA2_LEAF.der │ │ └── CPO_SUB_CA2.pem │ ├── mf │ │ └── MF_ROOT_CA.pem │ ├── mo │ │ ├── INTERMEDIATE_MO_CA_CERTS.pem │ │ ├── MO_ROOT_CA.der │ │ ├── MO_ROOT_CA.pem │ │ ├── MO_SUB_CA1.der │ │ ├── MO_SUB_CA1.pem │ │ ├── MO_SUB_CA2.der │ │ └── MO_SUB_CA2.pem │ └── v2g │ ├── V2G_ROOT_CA.der │ └── V2G_ROOT_CA.pem ├── client │ ├── csms │ │ ├── CPO_CERT_CHAIN.pem │ │ ├── CPO_SUB_CA1.key │ │ ├── CPO_SUB_CA2.key │ │ ├── SECC_LEAF.der │ │ ├── SECC_LEAF.key │ │ └── SECC_LEAF.pem │ ├── cso │ │ ├── CPO_CERT_CHAIN.pem │ │ ├── CPO_SUB_CA1.key │ │ ├── CPO_SUB_CA2.key │ │ ├── SECC_LEAF.der │ │ ├── SECC_LEAF.key │ │ └── SECC_LEAF.pem │ └── v2g │ └── V2G_ROOT_CA.key
If you're missing (some of) these files you might see error messages like these during startup:
void ocpp::PkiHandler::execOpenSSLRehash(boost::filesystem::path) :: Error executing the openssl rehash command for directory: /etc/everest/certs/ca/cso void ocpp::PkiHandler::execOpenSSLRehash(boost::filesystem::path) :: Error executing the openssl rehash command for directory: /etc/everest/certs/ca/csms void ocpp::PkiHandler::execOpenSSLRehash(boost::filesystem::path) :: Error executing the openssl rehash command for directory: /etc/everest/certs/ca/mf void ocpp::PkiHandler::execOpenSSLRehash(boost::filesystem::path) :: Error executing the openssl rehash command for directory: /etc/everest/certs/ca/mo void ocpp::PkiHandler::execOpenSSLRehash(boost::filesystem::path) :: Error executing the openssl rehash command for directory: /etc/everest/certs/ca/oem void ocpp::PkiHandler::execOpenSSLRehash(boost::filesystem::path) :: Error executing the openssl rehash command for directory: /etc/everest/certs/ca/v2g
You can (and in many cases MUST) register a number of callbacks so libocpp can interact with the charger. In EVerest most of this functionality is orchestrated by the "EvseManager" module, but you can also register your own callbacks interacting directly with your chargers software. Following is a list of callbacks that you must register and a few words about their purpose.
TODO: in a future version of libocpp the callbacks will be organised in a struct with optional members emphasizing the required and optional callbacks.
Some general notes: the "connector" parameter of some of the callbacks refers to the connector number as understood in the OCPP 1.6 specification, "0" means the whole charging station, the connectors with EVSEs used for charging cars start at "1".
-
register_pause_charging_callback
this callback is used by libocpp to request pausing of charging, the "connector" parameter tells you which connector/EVSE has to pause charging
-
register_resume_charging_callback
this callback is used by libocpp the request resuming of charging, the "connector" parameter tells you which connector/EVSE can resume charging
-
register_stop_transaction_callback
in EVerest this calls the EvseManagers stop_transaction command which "Stops transactions and cancels charging externally, charging can only be resumed by replugging car. EVSE will also stop transaction automatically e.g. on disconnect, so this only needs to be called if the transaction should end before." this will then signal the following events:
- ChargingFinished
- TransactionFinished
-
register_unlock_connector_callback
can be used by libocpp to force unlock a connector
-
register_reserve_now_callback
libocpp can use this to reserve a connector, reservation handling is outsourced to a reservation manager in EVerest that implements the reservation interface (everest-core/interfaces/reservation.yaml)
-
register_upload_diagnostics_callback
uses a function (in EVerest provided by the System module) to upload the requested diagnostics file
-
register_upload_logs_callback
uses a function (in EVerest provided by the System module) to upload the requested log file
-
register_update_firmware_callback
uses a function (in EVerest provided by the System module) to perform a firmware update
-
register_signed_update_firmware_callback
uses a function (in EVerest provided by the System module) to perform a signed firmware update
-
register_provide_token_callback
this callback is used in a remote start transaction to provide a token (prevalidated or not) to the authorization system
-
register_set_connection_timeout_callback
used by libocpp to set the authorization or plug in connection timeout in the authorization system based on the "ConnectionTimeout" configuration key
-
register_disable_evse_callback
used to disable the EVSE (ChangeAvailability.req)
-
register_enable_evse_callback
used to enable the EVSE (ChangeAvailability.req)
-
register_cancel_reservation_callback
used to cancel a reservation in the reservation manager (CancelReservation.req)
-
register_signal_set_charging_profiles_callback
used to signal that new charging schedule(s) have been set, you can then use get_all_composite_charging_schedules(duration_s) to get the new valid charging schedules
-
register_is_reset_allowed_callback
used to inquire (in EVerest from the System module) if a reset is allowed
-
register_reset_callback
used to perform a reset of the requested type
-
register_connection_state_changed_callback
used to inform about the connection state to the CSMS (connected = true, disconnected = false)
Functions that need to be triggered from the outside after new information is availble (on_... functions in the charge point API)
-
on_log_status_notification(int32_t request_id, std::string log_status)
can be used to notify libocpp of a log status notification
-
on_firmware_update_status_notification(int32_t request_id, std::string firmware_update_status)
can be used to notify libocpp of a firmware update status notification
-
on_meter_values(int32_t connector, const Powermeter& powermeter)
provides a Powermeter struct to libocpp (for sending meter values during charging sessions or periodically)
-
on_max_current_offered(int32_t connector, int32_t max_current)
the maximum current offered to the EV on this connector (in ampere)
The following functions are triggered depending on different so called "Session Events" from the EvseManager
each of these functions will have a small note what the Session Event was and what it triggers in libocpp
-
on_enabled(int32_t connector)
Notifies libocpp that the connector is functional and operational
-
on_disabled(int32_t connector)
Notifies libocpp that the connector is disabled
-
on_transaction_started
Notifies libocpp that a transaction at the given connector has started, this means that authorization is available and the car is plugged in.
Some of its parameters:
session_id is an internal session_id originating in the EvseManager to keep track of the transaction, this is NOT to be mistaken for the transactionId from the StartTransactionResponse in OCPP!
id_token is the token with which the transaction was authenticated
meter_start contains the meter value in Wh for the connector at start of the transaction
timestamp at the start of the transaction
-
on_transaction_stopped
Notifies libocpp that the transaction on the given connector with the given reason has been stopped.
Some of its parameters:
timestamp at the end of the transaction
energy_wh_import contains the meter value in Wh for the connector at end of the transaction
-
on_suspend_charging_ev
Notifies libocpp that the EV has paused charging
-
on_suspend_charging_evse
Notifies libocpp that the EVSE has paused charging
-
on_resume_charging
Notifies libocpp that charging has resumed
-
on_session_started
this is mostly used for logging and changing the connector state
-
on_session_stopped
this is mostly used for logging and changing the connector state
-
on_error
Notify libocpp of an error
-
on_reservation_start
Notifies libocpp that a reservation has started
-
on_reservation_end
Notifies libocpp that a reservation has ended
In EVerest authorization is handled by the Auth module and various auth token providers and validators. The OCPP module acts as both a token provider (for pre validated tokens in RemoteStartTransactions) and a token validator (using the authorize requests, or plug & charge) To use libocpp as a auth token validator (e.g. before starting a transaction) you can call the "authorize_id_token" function of the ChargePoint object
TODO
- Use provided sql database or implement your own storage drive
For Debian GNU/Linux 11 you will need the following dependencies:
sudo apt install build-essential cmake python3-pip libboost-all-dev libsqlite3-dev libssl-dev
Clone this repository.
git clone https://github.com/EVerest/libocpp
In the libocpp folder create a folder named build and cd into it. Execute cmake and then make install:
mkdir build && cd build
cmake ..
make install
Libocpp provides a small standalone OCPP1.6 client that you can control using command line.
Install the dependencies and libocpp as described in Install libocpp.
Make sure you modify the following config entries in the config.json file according to the CSMS you want to connect to before executing make install.
{
"Internal": {
"ChargePointId": "",
"CentralSystemURI": ""
}
}
Change into libocpp/build and execute cmake and then make install:
cd build
cmake -DLIBOCPP16_BUILD_EXAMPLES=ON -DCMAKE_INSTALL_PREFIX=./dist ..
make -j$(nproc) install
Use the following command to start the charge point. Replace the config with config-docker.json if you want to test with the SteVe CSMS running in a docker container.
./dist/bin/charge_point \
--maindir ./dist \
--conf config.json
Type help
to see a list of possible commands.
cmake -S . -B build
cmake --build build --target doxygen-ocpp
You will find the generated doxygen documentation at:
build/dist/docs/html/index.html
The main reference for the integration of libocpp for OCPP1.6 is the ocpp::v16::ChargePoint class defined in libocpp/include/ocpp/v16/charge_point.hpp .
If you want to run the unit tests in the tests subdirectory: install the needed dependencies. For Debian GNU/Linux 11 you can install it like this:
sudo apt install libgtest-dev lcov
python3 -m pip install gcovr
Run the unit tests
cmake .. -DBUILD_TESTING=ON
In doc/build-with-fetchcontent you can find an example how to build libocpp with FetchContent instead of EDM.