[API] add comments endpoint for single comment (#9494)

* add GET /repos/{owner}/{repo}/issues/comments/{id}
 and complete error list for swagger in other func

* add repo check

2 files changed, 85 insertions, 3 deletions

diff --git a/routers/api/v1/api.go b/routers/api/v1/api.go
index e4288f40f6..3f766c7a74 100644
--- a/routers/api/v1/api.go
+++ b/routers/api/v1/api.go
@@ -661,9 +661,10 @@ func RegisterRoutes(m *macaron.Macaron) {
 					m.Group("/comments", func() {
 						m.Get("", repo.ListRepoIssueComments)
 						m.Group("/:id", func() {
-							m.Combo("", reqToken()).
-								Patch(mustNotBeArchived, bind(api.EditIssueCommentOption{}), repo.EditIssueComment).
-								Delete(repo.DeleteIssueComment)
+							m.Combo("").
+								Get(repo.GetIssueComment).
+								Patch(mustNotBeArchived, reqToken(), bind(api.EditIssueCommentOption{}), repo.EditIssueComment).
+								Delete(reqToken(), repo.DeleteIssueComment)
 							m.Combo("/reactions").
 								Get(repo.GetIssueCommentReactions).
 								Post(bind(api.EditReactionOption{}), reqToken(), repo.PostIssueCommentReaction).
diff --git a/routers/api/v1/repo/issue_comment.go b/routers/api/v1/repo/issue_comment.go
index c13fc93cdf..3085c2e51f 100644
--- a/routers/api/v1/repo/issue_comment.go
+++ b/routers/api/v1/repo/issue_comment.go
@@ -204,6 +204,74 @@ func CreateIssueComment(ctx *context.APIContext, form api.CreateIssueCommentOpti
 	ctx.JSON(http.StatusCreated, comment.APIFormat())
 }
 
+// GetIssueComment Get a comment by ID
+func GetIssueComment(ctx *context.APIContext) {
+	// swagger:operation GET /repos/{owner}/{repo}/issues/comments/{id} issue issueGetComment
+	// ---
+	// summary: Get a comment
+	// consumes:
+	// - application/json
+	// 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: id
+	//   in: path
+	//   description: id of the comment
+	//   type: integer
+	//   format: int64
+	//   required: true
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/Comment"
+	//   "204":
+	//     "$ref": "#/responses/empty"
+	//   "403":
+	//     "$ref": "#/responses/forbidden"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
+
+	comment, err := models.GetCommentByID(ctx.ParamsInt64(":id"))
+	if err != nil {
+		if models.IsErrCommentNotExist(err) {
+			ctx.NotFound(err)
+		} else {
+			ctx.Error(http.StatusInternalServerError, "GetCommentByID", err)
+		}
+		return
+	}
+
+	if err = comment.LoadIssue(); err != nil {
+		ctx.InternalServerError(err)
+		return
+	}
+	if comment.Issue.RepoID != ctx.Repo.Repository.ID {
+		ctx.Status(http.StatusNotFound)
+		return
+	}
+
+	if comment.Type != models.CommentTypeComment {
+		ctx.Status(http.StatusNoContent)
+		return
+	}
+
+	if err := comment.LoadPoster(); err != nil {
+		ctx.Error(http.StatusInternalServerError, "comment.LoadPoster", err)
+		return
+	}
+
+	ctx.JSON(http.StatusOK, comment.APIFormat())
+}
+
 // EditIssueComment modify a comment of an issue
 func EditIssueComment(ctx *context.APIContext, form api.EditIssueCommentOption) {
 	// swagger:operation PATCH /repos/{owner}/{repo}/issues/comments/{id} issue issueEditComment
@@ -237,6 +305,13 @@ func EditIssueComment(ctx *context.APIContext, form api.EditIssueCommentOption)
 	// responses:
 	//   "200":
 	//     "$ref": "#/responses/Comment"
+	//   "204":
+	//     "$ref": "#/responses/empty"
+	//   "403":
+	//     "$ref": "#/responses/forbidden"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
+
 	editIssueComment(ctx, form)
 }
 
@@ -283,6 +358,8 @@ func EditIssueCommentDeprecated(ctx *context.APIContext, form api.EditIssueComme
 	//     "$ref": "#/responses/empty"
 	//   "403":
 	//     "$ref": "#/responses/forbidden"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
 
 	editIssueComment(ctx, form)
 }
@@ -343,6 +420,8 @@ func DeleteIssueComment(ctx *context.APIContext) {
 	//     "$ref": "#/responses/empty"
 	//   "403":
 	//     "$ref": "#/responses/forbidden"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
 
 	deleteIssueComment(ctx)
 }
@@ -380,6 +459,8 @@ func DeleteIssueCommentDeprecated(ctx *context.APIContext) {
 	//     "$ref": "#/responses/empty"
 	//   "403":
 	//     "$ref": "#/responses/forbidden"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
 
 	deleteIssueComment(ctx)
 }