Add CRAN package registry (#22331)

This PR adds a [CRAN](https://cran.r-project.org/) package registry.

![grafik](https://user-images.githubusercontent.com/1666336/210450039-d6fa6f77-20cd-4741-89a8-1624def267f7.png)

3 files changed, 287 insertions, 1 deletions

diff --git a/routers/api/packages/api.go b/routers/api/packages/api.go
index e715997e82..4f0f637fa5 100644
--- a/routers/api/packages/api.go
+++ b/routers/api/packages/api.go
@@ -22,6 +22,7 @@ import (
 	"code.gitea.io/gitea/routers/api/packages/conan"
 	"code.gitea.io/gitea/routers/api/packages/conda"
 	"code.gitea.io/gitea/routers/api/packages/container"
+	"code.gitea.io/gitea/routers/api/packages/cran"
 	"code.gitea.io/gitea/routers/api/packages/debian"
 	"code.gitea.io/gitea/routers/api/packages/generic"
 	"code.gitea.io/gitea/routers/api/packages/goproxy"
@@ -295,6 +296,24 @@ func CommonRoutes(ctx gocontext.Context) *web.Route {
 				conda.UploadPackageFile(ctx)
 			})
 		}, reqPackageAccess(perm.AccessModeRead))
+		r.Group("/cran", func() {
+			r.Group("/src", func() {
+				r.Group("/contrib", func() {
+					r.Get("/PACKAGES", cran.EnumerateSourcePackages)
+					r.Get("/PACKAGES{format}", cran.EnumerateSourcePackages)
+					r.Get("/{filename}", cran.DownloadSourcePackageFile)
+				})
+				r.Put("", reqPackageAccess(perm.AccessModeWrite), cran.UploadSourcePackageFile)
+			})
+			r.Group("/bin", func() {
+				r.Group("/{platform}/contrib/{rversion}", func() {
+					r.Get("/PACKAGES", cran.EnumerateBinaryPackages)
+					r.Get("/PACKAGES{format}", cran.EnumerateBinaryPackages)
+					r.Get("/{filename}", cran.DownloadBinaryPackageFile)
+				})
+				r.Put("", reqPackageAccess(perm.AccessModeWrite), cran.UploadBinaryPackageFile)
+			})
+		}, reqPackageAccess(perm.AccessModeRead))
 		r.Group("/debian", func() {
 			r.Get("/repository.key", debian.GetRepositoryKey)
 			r.Group("/dists/{distribution}", func() {
diff --git a/routers/api/packages/cran/cran.go b/routers/api/packages/cran/cran.go
new file mode 100644
index 0000000000..eb3f9a452b
--- /dev/null
+++ b/routers/api/packages/cran/cran.go
@@ -0,0 +1,267 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cran
+
+import (
+	"compress/gzip"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+
+	packages_model "code.gitea.io/gitea/models/packages"
+	cran_model "code.gitea.io/gitea/models/packages/cran"
+	"code.gitea.io/gitea/modules/context"
+	packages_module "code.gitea.io/gitea/modules/packages"
+	cran_module "code.gitea.io/gitea/modules/packages/cran"
+	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/routers/api/packages/helper"
+	packages_service "code.gitea.io/gitea/services/packages"
+)
+
+func apiError(ctx *context.Context, status int, obj interface{}) {
+	helper.LogAndProcessError(ctx, status, obj, func(message string) {
+		ctx.PlainText(status, message)
+	})
+}
+
+func EnumerateSourcePackages(ctx *context.Context) {
+	enumeratePackages(ctx, ctx.Params("format"), &cran_model.SearchOptions{
+		OwnerID:  ctx.Package.Owner.ID,
+		FileType: cran_module.TypeSource,
+	})
+}
+
+func EnumerateBinaryPackages(ctx *context.Context) {
+	enumeratePackages(ctx, ctx.Params("format"), &cran_model.SearchOptions{
+		OwnerID:  ctx.Package.Owner.ID,
+		FileType: cran_module.TypeBinary,
+		Platform: ctx.Params("platform"),
+		RVersion: ctx.Params("rversion"),
+	})
+}
+
+func enumeratePackages(ctx *context.Context, format string, opts *cran_model.SearchOptions) {
+	if format != "" && format != ".gz" {
+		apiError(ctx, http.StatusNotFound, nil)
+		return
+	}
+
+	pvs, err := cran_model.SearchLatestVersions(ctx, opts)
+	if err != nil {
+		apiError(ctx, http.StatusInternalServerError, err)
+		return
+	}
+	if len(pvs) == 0 {
+		apiError(ctx, http.StatusNotFound, nil)
+		return
+	}
+
+	pds, err := packages_model.GetPackageDescriptors(ctx, pvs)
+	if err != nil {
+		apiError(ctx, http.StatusInternalServerError, err)
+		return
+	}
+
+	var w io.Writer = ctx.Resp
+
+	if format == ".gz" {
+		ctx.Resp.Header().Set("Content-Type", "application/x-gzip")
+
+		gzw := gzip.NewWriter(w)
+		defer gzw.Close()
+
+		w = gzw
+	} else {
+		ctx.Resp.Header().Set("Content-Type", "text/plain;charset=utf-8")
+	}
+	ctx.Resp.WriteHeader(http.StatusOK)
+
+	for i, pd := range pds {
+		if i > 0 {
+			fmt.Fprintln(w)
+		}
+
+		var pfd *packages_model.PackageFileDescriptor
+		for _, d := range pd.Files {
+			if d.Properties.GetByName(cran_module.PropertyType) == opts.FileType &&
+				d.Properties.GetByName(cran_module.PropertyPlatform) == opts.Platform &&
+				d.Properties.GetByName(cran_module.PropertyRVersion) == opts.RVersion {
+				pfd = d
+				break
+			}
+		}
+
+		metadata := pd.Metadata.(*cran_module.Metadata)
+
+		fmt.Fprintln(w, "Package:", pd.Package.Name)
+		fmt.Fprintln(w, "Version:", pd.Version.Version)
+		if metadata.License != "" {
+			fmt.Fprintln(w, "License:", metadata.License)
+		}
+		if len(metadata.Depends) > 0 {
+			fmt.Fprintln(w, "Depends:", strings.Join(metadata.Depends, ", "))
+		}
+		if len(metadata.Imports) > 0 {
+			fmt.Fprintln(w, "Imports:", strings.Join(metadata.Imports, ", "))
+		}
+		if len(metadata.LinkingTo) > 0 {
+			fmt.Fprintln(w, "LinkingTo:", strings.Join(metadata.LinkingTo, ", "))
+		}
+		if len(metadata.Suggests) > 0 {
+			fmt.Fprintln(w, "Suggests:", strings.Join(metadata.Suggests, ", "))
+		}
+		needsCompilation := "no"
+		if metadata.NeedsCompilation {
+			needsCompilation = "yes"
+		}
+		fmt.Fprintln(w, "NeedsCompilation:", needsCompilation)
+		fmt.Fprintln(w, "MD5sum:", pfd.Blob.HashMD5)
+	}
+}
+
+func UploadSourcePackageFile(ctx *context.Context) {
+	uploadPackageFile(
+		ctx,
+		packages_model.EmptyFileKey,
+		map[string]string{
+			cran_module.PropertyType: cran_module.TypeSource,
+		},
+	)
+}
+
+func UploadBinaryPackageFile(ctx *context.Context) {
+	platform, rversion := ctx.FormTrim("platform"), ctx.FormTrim("rversion")
+	if platform == "" || rversion == "" {
+		apiError(ctx, http.StatusBadRequest, nil)
+		return
+	}
+
+	uploadPackageFile(
+		ctx,
+		platform+"|"+rversion,
+		map[string]string{
+			cran_module.PropertyType:     cran_module.TypeBinary,
+			cran_module.PropertyPlatform: platform,
+			cran_module.PropertyRVersion: rversion,
+		},
+	)
+}
+
+func uploadPackageFile(ctx *context.Context, compositeKey string, properties map[string]string) {
+	upload, close, err := ctx.UploadStream()
+	if err != nil {
+		apiError(ctx, http.StatusBadRequest, err)
+		return
+	}
+	if close {
+		defer upload.Close()
+	}
+
+	buf, err := packages_module.CreateHashedBufferFromReader(upload)
+	if err != nil {
+		apiError(ctx, http.StatusInternalServerError, err)
+		return
+	}
+	defer buf.Close()
+
+	pck, err := cran_module.ParsePackage(buf, buf.Size())
+	if err != nil {
+		if errors.Is(err, util.ErrInvalidArgument) {
+			apiError(ctx, http.StatusBadRequest, err)
+		} else {
+			apiError(ctx, http.StatusInternalServerError, err)
+		}
+		return
+	}
+
+	if _, err := buf.Seek(0, io.SeekStart); err != nil {
+		apiError(ctx, http.StatusInternalServerError, err)
+		return
+	}
+
+	_, _, err = packages_service.CreatePackageOrAddFileToExisting(
+		&packages_service.PackageCreationInfo{
+			PackageInfo: packages_service.PackageInfo{
+				Owner:       ctx.Package.Owner,
+				PackageType: packages_model.TypeCran,
+				Name:        pck.Name,
+				Version:     pck.Version,
+			},
+			SemverCompatible: false,
+			Creator:          ctx.Doer,
+			Metadata:         pck.Metadata,
+		},
+		&packages_service.PackageFileCreationInfo{
+			PackageFileInfo: packages_service.PackageFileInfo{
+				Filename:     fmt.Sprintf("%s_%s%s", pck.Name, pck.Version, pck.FileExtension),
+				CompositeKey: compositeKey,
+			},
+			Creator:    ctx.Doer,
+			Data:       buf,
+			IsLead:     true,
+			Properties: properties,
+		},
+	)
+	if err != nil {
+		switch err {
+		case packages_model.ErrDuplicatePackageFile:
+			apiError(ctx, http.StatusConflict, err)
+		case packages_service.ErrQuotaTotalCount, packages_service.ErrQuotaTypeSize, packages_service.ErrQuotaTotalSize:
+			apiError(ctx, http.StatusForbidden, err)
+		default:
+			apiError(ctx, http.StatusInternalServerError, err)
+		}
+		return
+	}
+
+	ctx.Status(http.StatusCreated)
+}
+
+func DownloadSourcePackageFile(ctx *context.Context) {
+	downloadPackageFile(ctx, &cran_model.SearchOptions{
+		OwnerID:  ctx.Package.Owner.ID,
+		FileType: cran_module.TypeSource,
+		Filename: ctx.Params("filename"),
+	})
+}
+
+func DownloadBinaryPackageFile(ctx *context.Context) {
+	downloadPackageFile(ctx, &cran_model.SearchOptions{
+		OwnerID:  ctx.Package.Owner.ID,
+		FileType: cran_module.TypeBinary,
+		Platform: ctx.Params("platform"),
+		RVersion: ctx.Params("rversion"),
+		Filename: ctx.Params("filename"),
+	})
+}
+
+func downloadPackageFile(ctx *context.Context, opts *cran_model.SearchOptions) {
+	pf, err := cran_model.SearchFile(ctx, opts)
+	if err != nil {
+		if errors.Is(err, util.ErrNotExist) {
+			apiError(ctx, http.StatusNotFound, err)
+		} else {
+			apiError(ctx, http.StatusInternalServerError, err)
+		}
+		return
+	}
+
+	s, _, err := packages_service.GetPackageFileStream(ctx, pf)
+	if err != nil {
+		if errors.Is(err, util.ErrNotExist) {
+			apiError(ctx, http.StatusNotFound, err)
+		} else {
+			apiError(ctx, http.StatusInternalServerError, err)
+		}
+		return
+	}
+	defer s.Close()
+
+	ctx.ServeContent(s, &context.ServeHeaderOptions{
+		Filename:     pf.Name,
+		LastModified: pf.CreatedUnix.AsLocalTime(),
+	})
+}
diff --git a/routers/api/v1/packages/package.go b/routers/api/v1/packages/package.go
index 0c9a134281..5129c7d4f0 100644
--- a/routers/api/v1/packages/package.go
+++ b/routers/api/v1/packages/package.go
@@ -40,7 +40,7 @@ func ListPackages(ctx *context.APIContext) {
 	//   in: query
 	//   description: package type filter
 	//   type: string
-	//   enum: [alpine, cargo, chef, composer, conan, conda, container, debian, generic, go, helm, maven, npm, nuget, pub, pypi, rpm, rubygems, swift, vagrant]
+	//   enum: [alpine, cargo, chef, composer, conan, conda, container, cran, debian, generic, go, helm, maven, npm, nuget, pub, pypi, rpm, rubygems, swift, vagrant]
 	// - name: q
 	//   in: query
 	//   description: name filter