

# OpenCAPIF SDK

![OpenCAPIF icon](./doc/images/OpenCAPIF-icon.jpg)

This repository develops a Python Software Development Kit(SDK) which focuses on connecting to OpenCAPIF (Common API Framework for 3GPP Northbound APIs) in a simple way, lowering integration complexity and allowing developers to focus on Network Applications (NetApps) or services development. 

OpenCAPIF SDK provides a set of libraries to enable either CAPIF provider and invoker roles, and other functions to simplify procedures calls towards OpenCAPIF entity.

Current version of OpenCAPIF SDK is compatible with following publicly available releases:
- [OpenCAPIF Release 1.0](https://ocf.etsi.org/documentation/v1.0.0-release/)

This document serves as the [main bootstrap reference](#netapp-developer-path) to start working with OpenCAPIF SDK. For advanced users, refer to [OpenCAPIF full documentation](./doc/sdk-full-documentation.md) section to dig into all available features.

# Table of Contents
 1. [NetApp developers](#netapp-developers)
 2. [OpenCAPIF SDK summary](#opencapif-sdk-summary)
 3. [OpenCAPIF SDK requirements](#opencapif-sdk-requirements)
 4. [NetApp developer path](#netapp-developer-path)
 5. [OpenCAPIF SDK Configuration](./doc/sdk-configuration.md)
 6. [**OpenCAPIF SDK full documentation**](./doc/sdk-full-documentation.md)
 7. [OpenCAPIF SDK known issues](./doc/sdk-issues.md)
 8. [OpenCAPIF SDK developers](./doc/sdk-installation.md)

# NetApp developers

In the scope of CAPIF, a NetApp (Network Application) refers to an external application or service that interacts with the 3GPP network via standardized APIs. These NetApps typically leverage the capabilities and services provided by the underlying mobile network infrastructure, such as network slicing, quality of service (QoS), or location services.

NetApps can be developed by third-party service providers, network operators, or other stakeholders to offer a wide range of services, including enhanced communication features, IoT solutions, or content delivery, and they use CAPIF as the unified framework for securely discovering, accessing, and utilizing 3GPP network APIs.

For that purpose NetApps play 2 different roles when interacting with CAPIF:
- **Invoker**: a NetApp acting as an Invoker is responsible for consuming APIs exposed by other services. This role represents an external application or service that  calls the 3GPP northbound APIs to utilize the network’s functionalities.

- **Provider**: a NetApp acting as a Provider is responsible for exposing its own APIs//services for use by Invokers. This role represents an entity that offers services through APIs, making them available to other external applications or Invokers.

**NetApps developers are the target users of OpenCAPIF SDK.**

## OpenCAPIF SDK summary

OpenCAPIF SDK brings a set of functions to integrate with the 5G Core's function CAPIF, as defined in [3GPP Technical Specification (TS) 29.222 V18.5.0 Common API Framework for 3GPP Northbound APIs](https://www.etsi.org/deliver/etsi_ts/129200_129299/129222/18.05.00_60/ts_129222v180500p.pdf). This section shows the mapping between the Python functions available in this SDK and the CAPIF OpenAPI APIs defined the reference standard:

| **3GPP CAPIF API**                                    | **OpenCAPIF SDK function**                                  | **Description**                                             |
|-------------------------------------------------------|-------------------------------------------------------------|-------------------------------------------------------------|
| /onboardedInvokers (POST)                             | onboard_invoker()                                           | Registers a new invoker.                                    |
| /onboardedInvokers/{onboardingId} (PUT)               | update_invoker()                                            | Updates an existing invoker for a specific `onboardingId`.                                |
| /onboardedInvokers/{onboardingId} (DELETE)            | offboard_invoker()                                          | Deletes an invoker for a specific `onboardingId`.                                         |
| registrations (POST)                                  | onboard_provider()                                          | Registers a new service provider.                           |
| /registrations/{registrationId} (PUT)                 | update_provider()                                           | Updates a service provider's registration for a specific `registrationId`.                  |
| /registrations/{registrationId} (DELETE)              | offboard_provider()                                         | Deletes a service provider's registration for a specific `registrationId`.                  |
| /allServiceAPIs (GET)                                 | discover()                                                  | Retrieves a list of all available service APIs.             |
| /trustedInvokers (PUT//POST)                          | discover()                                                  | Registers or updates trusted invokers.                      |
| /securities/{securityId}/token (GET)                  | get_tokens()                                                | Retrieves a security token for a specific `securityId`. This JWT token is used to query the targeted services.      |
| /{apfId}/service-apis(POST)                           | publish_services()                                          | Registers a new service API into the system for a specific `apfId`                |
| /{apfId}/service-apis/{serviceApiId} (DELETE)         | unpublish_service()                                         | Deletes a service API from the system for a specific `apfId`and `serviceApiId`                      |
| /{apfId}/service-apis/{serviceApiId} (PUT)            | update_service()                                            | Updates the details of an existing service API for a specific `apfId`and `serviceApiId`             |
| /{apfId}/service-apis/{serviceApiId} (GET)                           | get_service()                                               | Retrieves the details of a specific service API for a specific `apfId` and `serviceApiId`           |
| /{apfId}/service-apis (GET)            | get_all_services()                                          | Retrieves a list of all available service APIs for a specific `apfId`            |


NOTE: Above mentioned CAPIF APIs are defined in these 3GPP references:
- [CAPIF Invoker API specification](https://github.com/jdegre/5GC_APIs/blob/Rel-18/TS29222_CAPIF_API_Invoker_Management_API.yaml)
- [CAPIF Provider API specification](https://github.com/jdegre/5GC_APIs/blob/Rel-18/TS29222_CAPIF_API_Provider_Management_API.yaml)
- [CAPIF Discover API specification](https://github.com/jdegre/5GC_APIs/blob/Rel-18/TS29222_CAPIF_Discover_Service_API.yaml)
- [CAPIF Publish API specification](https://github.com/jdegre/5GC_APIs/blob/Rel-18/TS29222_CAPIF_Publish_Service_API.yaml) 
- [CAPIF Security API specification](https://github.com/jdegre/5GC_APIs/blob/Rel-18/TS29222_CAPIF_Security_API.yaml)

NOTE: In the [3GPP Technical Specification (TS) 29.222 V18.5.0 Common API Framework for 3GPP Northbound APIs](https://www.etsi.org/deliver/etsi_ts/129200_129299/129222/18.05.00_60/ts_129222v180500p.pdf) the `service` concept is understood as equal as the `API` concept.


## OpenCAPIF SDK requirements

To leverage the OpenCAPIF SDK, it must have a registered user in the target CAPIF instance. **Please contact the administrator to obtain the necessary predefined credentials (username and password).**

# Netapp developer path

The NetApp Developer Path guides the programmer through building and integrating NetApps using CAPIF. This path is divided into two key sections: [Invoker NetApp](#invoker-netapp-1) and Provider NetApp. Each section covers the essential flow and functions for developing NetApps interaction with CAPIF, whether the user is acting as an invoker consuming services or a provider offering them. By following this path, developers will gain a comprehensive understanding of how to effectively use the SDK within the CAPIF ecosystem.

Here is a good illustration about how a usual flow of a Netapp should work

[EXAMPLE](https://ocf.etsi.org/documentation/latest/testing/postman/)

## Invoker NetApp

Here is a code sample of the implementation of this hole [Invoker-Netapp](./netapp-samples/netapp-invoker-sample/netapp-invoker.py) sample.

1. **Create an Invoker object:** \
   Initialize the invoker by creating an instance of the `CAPIFInvokerConnector` class, passing the required configuration file:

   ```python
      invoker = CAPIFInvokerConnector(config_file=utilities.get_config_file())
   ```
   
2. **Onboard the Invoker**: \
   Register the invoker with the CAPIF system to enable access to APIs:

   ```python
      invoker.onboard_invoker()
   ```

3.	**Create a Service Discoverer object:** \
  Initialize the service discovery mechanism to search for available services:

    ```python
      service_discoverer = ServiceDiscoverer(config_file=utilities.get_config_file())
    ```

4.	**Discover available services:** \
  Use the discover() method to retrieve a list of available APIs:

  DISCLAIMER: if it's the first time the user runs discover() it will appear a warning alert like this

      WARNING - Received 404 error, redirecting to register security service

    ```python
      service_discoverer.discover()
    ```
  
    

5.	**Retrieve security tokens:** \
  Use the get_tokens() method to obtain the necessary tokens for authenticating API requests: 
  
    ```python
      invoker.get_tokens()
    ```
Then all information for using the available APIs would be at Capif_api_security_context_details.json 

This file would be placed in the invoker_folder path, more specifically in the folder that corresponds of the capif_username used in the config_file.

Here is a sample of this Capif_api_security_context_details [file](./samples/capif_api_security_context_details-sample.json) 

This image highlights Invoker path using SDK code:

![INVOKER_PATH](./doc/images/Flujo%20completo-INVOKER%20PATH.jpg)

### Important information for Invoker consumer

In the `invoker_folder`, it will be located several folders with each `capif_username` it has been onboarded as a provider. For each folder, it could be found:

- `Capif_api_security_context_details.json`: This file contains the information of the invoker. It will contain:
        
    1. The `api_invoker_id`.
    2. If the Service Discovery Functionality has already been used , it will be found all the available APIs with their information.
    3. If the Service Get Token functionality has already been used , it will be found the access token for using the APIs that has already been discovered.

## Provider NetApp

A NetApp development running as a Provider would typically follow this process step by step, making use of the SDK:

Here is a sample of the implementation of this hole [Provider-Netapp](./netapp-samples/netapp-provider-sample/netapp-provider.py)

1. **Create a Provider object:** \
   Initialize the provider by creating an instance of the `CAPIFProviderConnector` class, passing the required configuration file:

    ```python
      provider = CAPIFProviderConnector(config_file=utilities.get_config_file())
    ```

2. **Onboard the Provider:** \
    Register the provider with the CAPIF system to enable the publication of APIs:

    ```python
      provider.onboard_provider()
    ```

3. **Prepare API details:** \
   Locate the provider API details in the provider_folder path, more specifically in the username folder. Choose the APF (API Publishing Function) and AEFs (API Exposing Function) identifiers, and fulfil the publish_req structure and the api_description_path:

<p align="center">
  <img src="./doc/images/capif-provider-details-example.png" alt="example" width="400"/>
  <img src="./doc/images/publish_req-example.png" alt="config-example"  width="400"/>
</p>

4. **Publish the services:** \
   Use the publish_services() method to register the APIs with the CAPIF framework(don't forget to update the CAPIFProviderConnector constructor in order to use the new APF and AEFs):

    ```python
      provider = CAPIFProviderConnector(config_file=utilities.get_config_file())
      provider.publish_services()
    ```

Here is a sample of the implementation of this whole [functionality](./netapp-samples/netapp-provider-sample/netapp-provider.py).

This image highlights Provider path using SDK code:

![PROVIDER_PATH](./doc/images/Flujo%20completo-PROVIDER%20PATH.jpg)

### Important information for Provider consumer

Within the `provider_folder`, the SDK will store some folders named with the provided `capif_username` it has been registered from administrator. At each folder, there will be found the following files:

- `capif_provider_details.json`: contains all the APFs and AEFs ids that have already onboarded with this `capif_username`,
- `CAPIF_<api_name><API_id>.json`: if it is already published or updated an API, it will contain a copy of the last payload,
- `service_received.json`: if it is already used to get an API or get all APIs functionality, it will contain the response of last request,
- `published-apis.json`: Contains the currently published APIs with their `ApiId`.

