Refactor routers directory (#15800)

* refactor routers directory

* move func used for web and api to common

* make corsHandler a function to prohibit side efects

* rm unused func

Co-authored-by: 6543 <6543@obermui.de>

routers/web/repo/issue_watch.go

@@ -0,0 +1,57 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package repo
+
+import (
+	"net/http"
+	"strconv"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/log"
+)
+
+// IssueWatch sets issue watching
+func IssueWatch(ctx *context.Context) {
+	issue := GetActionIssue(ctx)
+	if ctx.Written() {
+		return
+	}
+
+	if !ctx.IsSigned || (ctx.User.ID != issue.PosterID && !ctx.Repo.CanReadIssuesOrPulls(issue.IsPull)) {
+		if log.IsTrace() {
+			if ctx.IsSigned {
+				issueType := "issues"
+				if issue.IsPull {
+					issueType = "pulls"
+				}
+				log.Trace("Permission Denied: User %-v not the Poster (ID: %d) and cannot read %s in Repo %-v.\n"+
+					"User in Repo has Permissions: %-+v",
+					ctx.User,
+					log.NewColoredIDValue(issue.PosterID),
+					issueType,
+					ctx.Repo.Repository,
+					ctx.Repo.Permission)
+			} else {
+				log.Trace("Permission Denied: Not logged in")
+			}
+		}
+		ctx.Error(http.StatusForbidden)
+		return
+	}
+
+	watch, err := strconv.ParseBool(ctx.Req.PostForm.Get("watch"))
+	if err != nil {
+		ctx.ServerError("watch is not bool", err)
+		return
+	}
+
+	if err := models.CreateOrUpdateIssueWatch(ctx.User.ID, issue.ID, watch); err != nil {
+		ctx.ServerError("CreateOrUpdateIssueWatch", err)
+		return
+	}
+
+	ctx.Redirect(issue.HTMLURL(), http.StatusSeeOther)
+}