Surfacing PackageType as part of NuGet search protocol

Issue

#7594 - Surface PackageType query parameter in the NuGet.org search API

Problem

When searching for packages, it is not possible to limit results to a specific PackageType.

Who is the customer?

dotnet.exe - the ability to search for dotnet CLI tool only packages on NuGet.org

Evidence

Today, the state-of-the-art is this manually maintained list - https://github.com/natemcmaster/dotnet-tools

Solution

• Addendum to NuGetSearch Protocol - PackageType
• This is an extension to the protocol defined at https://docs.microsoft.com/en-us/nuget/api/search-query-service-resource
• Current usage of package types:

PackageTypeName	Count
(empty)	1855381
DotnetTool,	6590
Template,	4046
DotnetCliTool,	1209
MSBuildSdk,	758
Dependency,	526
AzureSiteExtension,	463
DotnetPlatform,	213
bugshooting.plugin.v3.output,	23
TestPackageType,	7
Passby.Microservice.Template,	6
MicroServiceTemplate,	6
WindowsAdminCenterExtension,	3
aspnetcoreapi,	2
Template,Template,	2
Hello,Hello2,Hello3,	1
BoostedLib,	1
Native,	1
CodingTool,	1
DotnetCliTool,Dependency,	1
Data,	1

Non-goal:

• We will NOT support queries by packageTypeVersion. This includes returning it in the search response as of now.
• PackageType will not be forwarded to the registration. There are currently no scenarios that require this.

1. Request Protocol Updates:

`GET {@id}?q={QUERY}&skip={SKIP}&take={TAKE}&prerelease={PRERELEASE}&semVerLevel={SEMVERLEVEL}&packageType={PACKAGETYPE}`

• "packagetype" field MAY be provided to further filter results.
• If "packagetype" is provided, {PACKAGETYPE} MAY BE provided and SHOULD BE any string.
  • {PACKAGETYPE} search will NOT be case sensitive.
• If {PACKAGETYPE} is not a valid package type as per https://github.com/NuGet/Home/wiki/Package-Type-%5BPacking%5D, an emtpy result MUST BE returned.
• If {PACKAGETYPE} is empty, no filter will be applied.
  • Passing no value to the packageType parameter will behave as if the parameter was not passed.
• Response will contain packages for which the LATEST VERSION has at least one packageType that matches {PACKAGETYPE}.
• LATEST VERSION is the latest version as defined by the criteria given in the query. Dependent on values of:
  • prerelease={PRERELEASE}
  • semVerLevel={SEMVERLEVEL}

2. Search Response Updates

2.1 Response Shape update:

{
	"totalHits": int,
	"data": [
		"id": string,
		... (further fields omitted for brevity. See https://docs.microsoft.com/en-us/nuget/api/search-query-service-resource for complete list)
		"verified": boolean,
		"packageTypes": [
			{
				"name": string
			}
		]
	]
}

2.2 Description

• "packageTypes" MUST ALWAYS be present.
• "packageTypes" MUST HAVE a length of at least 1 (one) Name MUST BE a valid package type as specified by https://github.com/NuGet/Home/wiki/Package-Type-%5BPacking%5D

3. Catalog Protocol Updates

3.1 Catalog leaf Shape updates:

{
	"authors": string,
	... (further fields omitted for brevity. See https://docs.microsoft.com/en-us/nuget/api/catalog-resource for complete list)
	"verbatimVersion": string,
	"packageTypes: [
		{
			"name": string,
			"version": string
		}
	]
}

3.2 Description

• "packagetypes" MUST NOT be present if nuspec does not specify any (this includes implied dependency)
• If "packagetypes" is present, it MUST BE of length AT LEAST 1 (one)
• Name MUST BE a valid package type as specified by https://github.com/NuGet/Home/wiki/Package-Type-%5BPacking%5D
• Version MAY BE present IF and ONLY IF it was specified in the corresponding package nuspec

Note: Currently (2019.12.13), packageTypes node in catalog will either be not present (no packageTypes node in nuspec), or an empty string (packageTypes node present in nuspec).