Add endpoint to support direct download of specific package or extension

[jcfr]

Is your feature request related to a problem? Please describe.

Downloading a specific package without using the python client currently requires multiple calls. This lead to complex implementation.

For example:

# Get app_id
app_id=$(curl -X GET --header "Accept: application/json" "https://slicer-packages.kitware.com/api/v1/app?name=Slicer" | jq ".[0]._id" -r)
https://slicer-packages.kitware.com/api/v1/app?name=Slicer

app_id=5f4474d0e1d8c75dfc705482
echo "app_id: ${app_id}"

# Get item_id
revision=29917
os=macosx
arch=amd64
item_id=$(curl -X GET --header "Accept: application/json" "https://slicer-packages.kitware.com/api/v1/app/${app_id}/package?os=${os}&arch=${arch}&revision=${revision}" -s | jq ".[0]._id" -r)
echo "item_id: ${item_id}"

# Get file_id
curl -X GET "https://slicer-packages.kitware.com/api/v1/item/${item_id}/download" -O

Describe the solution you'd like

Add new endpoints.

There are few possible approaches to define the routes

Explicitly include release_id_or_name, os, arch, revision

For example:

GET /app/:app_id_or_name/:release_id_or_name/package/:os/:arch/:revision/download
GET /app/:app_id_or_name/:release_id_or_name/extension/:os/:arch/:revision/download

where:

• app_id_or_name: 5f4474d0e1d8c75dfc705482 or Slicer
• release_id_or_name: draft, release name like 4.10, or id of the release
• os: linux, macosx or `win
• arch: amd64
• revision: 29917

Examples:

/app/Slicer/4.15/package/macosx/amd64/29917/download
/app/Slicer/draft/package/macosx/amd64/29917/download

Only with os, arch, revision

GET /app/:app_id_or_name/package/:os/:arch/:revision/download
GET /app/:app_id_or_name/extension/:os/:arch/:revision/download

and then additional parameter would be passed using &param1=value1.

All filters as parameters

GET /app/:app_id_or_name/package/download
GET /app/:app_id_or_name/extension/download

If more than packages is found, report an error requesting user to be more specific with specific filters.