Fixes #2738 - Adds the /git/tags API endpoint (#7138)

* Fixes #2738 - /git/tags API

* proper URLs

* Adds function comments

* Updates swagger

* Removes newline from tag message

* Removes trailing newline from commit message

* Adds integration test

* Removed debugging

* Adds tests

* Fixes bug where multiple tags of same commit show wrong tag name

* Fix formatting

* Removes unused varaible

* Fix to annotated tag function names and response

* Update modules/git/repo_tag.go

Co-Authored-By: Lauris BH <lauris@nix.lv>

* Uses TagPrefix

* Changes per review, better error handling for getting tag and commit IDs

* Fix to getting commit ID

* Fix to getting commit ID

* Fix to getting commit ID

* Fix to getting commit ID

5 files changed, 133 insertions, 31 deletions

diff --git a/routers/api/v1/api.go b/routers/api/v1/api.go
index c1561200cd..2268c1be38 100644
--- a/routers/api/v1/api.go
+++ b/routers/api/v1/api.go
@@ -751,6 +751,7 @@ func RegisterRoutes(m *macaron.Macaron) {
 						Post(reqToken(), bind(api.CreateStatusOption{}), repo.NewCommitStatus)
 				}, reqRepoReader(models.UnitTypeCode))
 				m.Group("/commits/:ref", func() {
+					// TODO: Add m.Get("") for single commit (https://developer.github.com/v3/repos/commits/#get-a-single-commit)
 					m.Get("/status", repo.GetCombinedCommitStatusByRef)
 					m.Get("/statuses", repo.GetCommitStatusesByRef)
 				}, reqRepoReader(models.UnitTypeCode))
@@ -762,6 +763,7 @@ func RegisterRoutes(m *macaron.Macaron) {
 					m.Get("/refs/*", repo.GetGitRefs)
 					m.Get("/trees/:sha", context.RepoRef(), repo.GetTree)
 					m.Get("/blobs/:sha", context.RepoRef(), repo.GetBlob)
+					m.Get("/tags/:sha", context.RepoRef(), repo.GetTag)
 				}, reqRepoReader(models.UnitTypeCode))
 				m.Group("/contents", func() {
 					m.Get("/*", repo.GetFileContents)
diff --git a/routers/api/v1/convert/convert.go b/routers/api/v1/convert/convert.go
index ba61c7e46c..a982cb8d37 100644
--- a/routers/api/v1/convert/convert.go
+++ b/routers/api/v1/convert/convert.go
@@ -6,6 +6,7 @@ package convert
 
 import (
 	"fmt"
+	"time"
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/git"
@@ -26,7 +27,7 @@ func ToEmail(email *models.EmailAddress) *api.Email {
 	}
 }
 
-// ToBranch convert a commit and branch to an api.Branch
+// ToBranch convert a git.Commit and git.Branch to an api.Branch
 func ToBranch(repo *models.Repository, b *git.Branch, c *git.Commit) *api.Branch {
 	return &api.Branch{
 		Name:   b.Name,
@@ -34,23 +35,18 @@ func ToBranch(repo *models.Repository, b *git.Branch, c *git.Commit) *api.Branch
 	}
 }
 
-// ToTag convert a tag to an api.Tag
+// ToTag convert a git.Tag to an api.Tag
 func ToTag(repo *models.Repository, t *git.Tag) *api.Tag {
 	return &api.Tag{
-		Name: t.Name,
-		Commit: struct {
-			SHA string `json:"sha"`
-			URL string `json:"url"`
-		}{
-			SHA: t.ID.String(),
-			URL: util.URLJoin(repo.Link(), "commit", t.ID.String()),
-		},
-		ZipballURL: util.URLJoin(repo.Link(), "archive", t.Name+".zip"),
-		TarballURL: util.URLJoin(repo.Link(), "archive", t.Name+".tar.gz"),
+		Name:       t.Name,
+		ID:         t.ID.String(),
+		Commit:     ToCommitMeta(repo, t),
+		ZipballURL: util.URLJoin(repo.HTMLURL(), "archive", t.Name+".zip"),
+		TarballURL: util.URLJoin(repo.HTMLURL(), "archive", t.Name+".tar.gz"),
 	}
 }
 
-// ToCommit convert a commit to api.PayloadCommit
+// ToCommit convert a git.Commit to api.PayloadCommit
 func ToCommit(repo *models.Repository, c *git.Commit) *api.PayloadCommit {
 	authorUsername := ""
 	if author, err := models.GetUserByEmail(c.Author.Email); err == nil {
@@ -66,17 +62,10 @@ func ToCommit(repo *models.Repository, c *git.Commit) *api.PayloadCommit {
 		log.Error("GetUserByEmail: %v", err)
 	}
 
-	verif := models.ParseCommitWithSignature(c)
-	var signature, payload string
-	if c.Signature != nil {
-		signature = c.Signature.Signature
-		payload = c.Signature.Payload
-	}
-
 	return &api.PayloadCommit{
 		ID:      c.ID.String(),
 		Message: c.Message(),
-		URL:     util.URLJoin(repo.Link(), "commit", c.ID.String()),
+		URL:     util.URLJoin(repo.HTMLURL(), "commit", c.ID.String()),
 		Author: &api.PayloadUser{
 			Name:     c.Author.Name,
 			Email:    c.Author.Email,
@@ -87,13 +76,24 @@ func ToCommit(repo *models.Repository, c *git.Commit) *api.PayloadCommit {
 			Email:    c.Committer.Email,
 			UserName: committerUsername,
 		},
-		Timestamp: c.Author.When,
-		Verification: &api.PayloadCommitVerification{
-			Verified:  verif.Verified,
-			Reason:    verif.Reason,
-			Signature: signature,
-			Payload:   payload,
-		},
+		Timestamp:    c.Author.When,
+		Verification: ToVerification(c),
+	}
+}
+
+// ToVerification convert a git.Commit.Signature to an api.PayloadCommitVerification
+func ToVerification(c *git.Commit) *api.PayloadCommitVerification {
+	verif := models.ParseCommitWithSignature(c)
+	var signature, payload string
+	if c.Signature != nil {
+		signature = c.Signature.Signature
+		payload = c.Signature.Payload
+	}
+	return &api.PayloadCommitVerification{
+		Verified:  verif.Verified,
+		Reason:    verif.Reason,
+		Signature: signature,
+		Payload:   payload,
 	}
 }
 
@@ -242,3 +242,45 @@ func ToUser(user *models.User, signed, admin bool) *api.User {
 	}
 	return result
 }
+
+// ToAnnotatedTag convert git.Tag to api.AnnotatedTag
+func ToAnnotatedTag(repo *models.Repository, t *git.Tag, c *git.Commit) *api.AnnotatedTag {
+	return &api.AnnotatedTag{
+		Tag:          t.Name,
+		SHA:          t.ID.String(),
+		Object:       ToAnnotatedTagObject(repo, c),
+		Message:      t.Message,
+		URL:          util.URLJoin(repo.APIURL(), "git/tags", t.ID.String()),
+		Tagger:       ToCommitUser(t.Tagger),
+		Verification: ToVerification(c),
+	}
+}
+
+// ToAnnotatedTagObject convert a git.Commit to an api.AnnotatedTagObject
+func ToAnnotatedTagObject(repo *models.Repository, commit *git.Commit) *api.AnnotatedTagObject {
+	return &api.AnnotatedTagObject{
+		SHA:  commit.ID.String(),
+		Type: string(git.ObjectCommit),
+		URL:  util.URLJoin(repo.APIURL(), "git/commits", commit.ID.String()),
+	}
+}
+
+// ToCommitUser convert a git.Signature to an api.CommitUser
+func ToCommitUser(sig *git.Signature) *api.CommitUser {
+	return &api.CommitUser{
+		Identity: api.Identity{
+			Name:  sig.Name,
+			Email: sig.Email,
+		},
+		Date: sig.When.UTC().Format(time.RFC3339),
+	}
+}
+
+// ToCommitMeta convert a git.Tag to an api.CommitMeta
+func ToCommitMeta(repo *models.Repository, tag *git.Tag) *api.CommitMeta {
+	return &api.CommitMeta{
+		SHA: tag.ID.String(),
+		// TODO: Add the /commits API endpoint and use it here (https://developer.github.com/v3/repos/commits/#get-a-single-commit)
+		URL: util.URLJoin(repo.APIURL(), "git/commits", tag.ID.String()),
+	}
+}
diff --git a/routers/api/v1/repo/git_ref.go b/routers/api/v1/repo/git_ref.go
index 2ec8749058..e15f699a1d 100644
--- a/routers/api/v1/repo/git_ref.go
+++ b/routers/api/v1/repo/git_ref.go
@@ -100,8 +100,7 @@ func getGitRefsInternal(ctx *context.APIContext, filter string) {
 			Object: &api.GitObject{
 				SHA:  refs[i].Object.String(),
 				Type: refs[i].Type,
-				// TODO: Add commit/tag info URL
-				//URL:  ctx.Repo.Repository.APIURL() + "/git/" + refs[i].Type + "s/" + refs[i].Object.String(),
+				URL:  ctx.Repo.Repository.APIURL() + "/git/" + refs[i].Type + "s/" + refs[i].Object.String(),
 			},
 		}
 	}
diff --git a/routers/api/v1/repo/tag.go b/routers/api/v1/repo/tag.go
index dd1b5aa7c1..ecf580e1b0 100644
--- a/routers/api/v1/repo/tag.go
+++ b/routers/api/v1/repo/tag.go
@@ -7,6 +7,7 @@ package repo
 import (
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/routers/api/v1/convert"
+	"net/http"
 
 	api "code.gitea.io/gitea/modules/structs"
 )
@@ -45,3 +46,47 @@ func ListTags(ctx *context.APIContext) {
 
 	ctx.JSON(200, &apiTags)
 }
+
+// GetTag get the tag of a repository.
+func GetTag(ctx *context.APIContext) {
+	// swagger:operation GET /repos/{owner}/{repo}/git/tags/{sha} repository GetTag
+	// ---
+	// summary: Gets the tag of a repository.
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: owner
+	//   in: path
+	//   description: owner of the repo
+	//   type: string
+	//   required: true
+	// - name: repo
+	//   in: path
+	//   description: name of the repo
+	//   type: string
+	//   required: true
+	// - name: sha
+	//   in: path
+	//   description: sha of the tag
+	//   type: string
+	//   required: true
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/AnnotatedTag"
+
+	sha := ctx.Params("sha")
+	if len(sha) == 0 {
+		ctx.Error(http.StatusBadRequest, "", "SHA not provided")
+		return
+	}
+
+	if tag, err := ctx.Repo.GitRepo.GetAnnotatedTag(sha); err != nil {
+		ctx.Error(http.StatusBadRequest, "GetTag", err)
+	} else {
+		commit, err := tag.Commit()
+		if err != nil {
+			ctx.Error(http.StatusBadRequest, "GetTag", err)
+		}
+		ctx.JSON(http.StatusOK, convert.ToAnnotatedTag(ctx.Repo.Repository, tag, commit))
+	}
+}
diff --git a/routers/api/v1/swagger/repo.go b/routers/api/v1/swagger/repo.go
index e7df0b8f71..25354b3d66 100644
--- a/routers/api/v1/swagger/repo.go
+++ b/routers/api/v1/swagger/repo.go
@@ -38,11 +38,25 @@ type swaggerResponseBranchList struct {
 
 // TagList
 // swagger:response TagList
-type swaggerReponseTagList struct {
+type swaggerResponseTagList struct {
 	// in:body
 	Body []api.Tag `json:"body"`
 }
 
+// Tag
+// swagger:response Tag
+type swaggerResponseTag struct {
+	// in:body
+	Body api.Tag `json:"body"`
+}
+
+// AnnotatedTag
+// swagger:response AnnotatedTag
+type swaggerResponseAnnotatedTag struct {
+	// in:body
+	Body api.AnnotatedTag `json:"body"`
+}
+
 // Reference
 // swagger:response Reference
 type swaggerResponseReference struct {