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/common/repo.go

@@ -0,0 +1,127 @@
+// Copyright 2021 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 common
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"code.gitea.io/gitea/modules/charset"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/httpcache"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
+	"code.gitea.io/gitea/services/archiver"
+)
+
+// ServeBlob download a git.Blob
+func ServeBlob(ctx *context.Context, blob *git.Blob) error {
+	if httpcache.HandleGenericETagCache(ctx.Req, ctx.Resp, `"`+blob.ID.String()+`"`) {
+		return nil
+	}
+
+	dataRc, err := blob.DataAsync()
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err = dataRc.Close(); err != nil {
+			log.Error("ServeBlob: Close: %v", err)
+		}
+	}()
+
+	return ServeData(ctx, ctx.Repo.TreePath, blob.Size(), dataRc)
+}
+
+// Download an archive of a repository
+func Download(ctx *context.Context) {
+	uri := ctx.Params("*")
+	aReq := archiver.DeriveRequestFrom(ctx, uri)
+
+	if aReq == nil {
+		ctx.Error(http.StatusNotFound)
+		return
+	}
+
+	downloadName := ctx.Repo.Repository.Name + "-" + aReq.GetArchiveName()
+	complete := aReq.IsComplete()
+	if !complete {
+		aReq = archiver.ArchiveRepository(aReq)
+		complete = aReq.WaitForCompletion(ctx)
+	}
+
+	if complete {
+		ctx.ServeFile(aReq.GetArchivePath(), downloadName)
+	} else {
+		ctx.Error(http.StatusNotFound)
+	}
+}
+
+// ServeData download file from io.Reader
+func ServeData(ctx *context.Context, name string, size int64, reader io.Reader) error {
+	buf := make([]byte, 1024)
+	n, err := reader.Read(buf)
+	if err != nil && err != io.EOF {
+		return err
+	}
+	if n >= 0 {
+		buf = buf[:n]
+	}
+
+	ctx.Resp.Header().Set("Cache-Control", "public,max-age=86400")
+
+	if size >= 0 {
+		ctx.Resp.Header().Set("Content-Length", fmt.Sprintf("%d", size))
+	} else {
+		log.Error("ServeData called to serve data: %s with size < 0: %d", name, size)
+	}
+	name = path.Base(name)
+
+	// Google Chrome dislike commas in filenames, so let's change it to a space
+	name = strings.ReplaceAll(name, ",", " ")
+
+	st := typesniffer.DetectContentType(buf)
+
+	if st.IsText() || ctx.QueryBool("render") {
+		cs, err := charset.DetectEncoding(buf)
+		if err != nil {
+			log.Error("Detect raw file %s charset failed: %v, using by default utf-8", name, err)
+			cs = "utf-8"
+		}
+		ctx.Resp.Header().Set("Content-Type", "text/plain; charset="+strings.ToLower(cs))
+	} else {
+		ctx.Resp.Header().Set("Access-Control-Expose-Headers", "Content-Disposition")
+
+		if (st.IsImage() || st.IsPDF()) && (setting.UI.SVG.Enabled || !st.IsSvgImage()) {
+			ctx.Resp.Header().Set("Content-Disposition", fmt.Sprintf(`inline; filename="%s"`, name))
+			if st.IsSvgImage() {
+				ctx.Resp.Header().Set("Content-Security-Policy", "default-src 'none'; style-src 'unsafe-inline'; sandbox")
+				ctx.Resp.Header().Set("X-Content-Type-Options", "nosniff")
+				ctx.Resp.Header().Set("Content-Type", typesniffer.SvgMimeType)
+			}
+		} else {
+			ctx.Resp.Header().Set("Content-Disposition", fmt.Sprintf(`attachment; filename="%s"`, name))
+			if setting.MimeTypeMap.Enabled {
+				fileExtension := strings.ToLower(filepath.Ext(name))
+				if mimetype, ok := setting.MimeTypeMap.Map[fileExtension]; ok {
+					ctx.Resp.Header().Set("Content-Type", mimetype)
+				}
+			}
+		}
+	}
+
+	_, err = ctx.Resp.Write(buf)
+	if err != nil {
+		return err
+	}
+	_, err = io.Copy(ctx.Resp, reader)
+	return err
+}