forgejo-federation/routers/api/packages/README.md

Gitea Package Registry

This document gives a brief overview how the package registry is organized in code.

Structure

The package registry code is divided into multiple modules to split the functionality and make code reuse possible.

Module	Description
models/packages	Common methods and models used by all registry types
models/packages/<type>	Methods used by specific registry type. There should be no need to use type specific models.
modules/packages	Common methods and types used by multiple registry types
modules/packages/<type>	Registry type specific methods and types (e.g. metadata extraction of package files)
routers/api/packages	Route definitions for all registry types
routers/api/packages/<type>	Route implementation for a specific registry type
services/packages	Helper methods used by registry types to handle common tasks like package creation and deletion in routers
services/packages/<type>	Registry type specific methods used by routers and services

Models

Every package registry implementation uses the same underlaying models:

Model	Description
Package	The root of a package providing values fixed for every version (e.g. the package name)
PackageVersion	A version of a package containing metadata (e.g. the package description)
PackageFile	A file of a package describing its content (e.g. file name)
PackageBlob	The content of a file (may be shared by multiple files)
PackageProperty	Additional properties attached to Package, PackageVersion or PackageFile (e.g. used if metadata is needed for routing)

The following diagram shows the relationship between the models:

Package <1---*> PackageVersion <1---*> PackageFile <*---1> PackageBlob

Adding a new package registry type

Before adding a new package registry type have a look at the existing implementation to get an impression of how it could work. Most registry types offer endpoints to retrieve the metadata, upload and download package files. The upload endpoint is often the heavy part because it must validate the uploaded blob, extract metadata and create the models. The methods to validate and extract the metadata should be added in the modules/packages/<type> package. If the upload is valid the methods in services/packages allow to store the upload and create the corresponding models. It depends if the registry type allows multiple files per package version which method should be called:

• CreatePackageAndAddFile: error if package version already exists
• CreatePackageOrAddFileToExisting: error if file already exists
• AddFileToExistingPackage: error if package version does not exist or file already exists

services/packages also contains helper methods to download a file or to remove a package version. There are no helper methods for metadata endpoints because they are very type specific.