Moving file response functionality to shared folder (#22226)

* Moving file response functionality to shared folder

* Linter fixes

* Added the attachment serve to shared folder

* Removed the unwanted logs

* import fixes

* Linter fixes

* License added

* Moved UnsafeContentTypes and MediaContentTypes from api4

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

api4/cloud.go

@@ -14,6 +14,7 @@ import (
 	"github.com/mattermost/mattermost-server/v6/audit"
 	"github.com/mattermost/mattermost-server/v6/model"
 	"github.com/mattermost/mattermost-server/v6/shared/mlog"
+	"github.com/mattermost/mattermost-server/v6/shared/web"
 )
 
 func (api *API) InitCloud() {
@@ -647,7 +648,7 @@ func getSubscriptionInvoicePDF(c *Context, w http.ResponseWriter, r *http.Reques
 		return
 	}
 
-	writeFileResponse(
+	web.WriteFileResponse(
 		filename,
 		"application/pdf",
 		int64(binary.Size(pdfData)),

api4/file.go

@@ -11,15 +11,14 @@ import (
 	"mime"
 	"mime/multipart"
 	"net/http"
-	"net/url"
 	"strconv"
-	"strings"
 	"time"
 
 	"github.com/mattermost/mattermost-server/v6/app"
 	"github.com/mattermost/mattermost-server/v6/audit"
 	"github.com/mattermost/mattermost-server/v6/model"
 	"github.com/mattermost/mattermost-server/v6/shared/mlog"
+	"github.com/mattermost/mattermost-server/v6/shared/web"
 	"github.com/mattermost/mattermost-server/v6/utils"
 )
 
@@ -30,28 +29,6 @@ const (
 	ThumbnailImageType = "image/jpeg"
 )
 
-var UnsafeContentTypes = [...]string{
-	"application/javascript",
-	"application/ecmascript",
-	"text/javascript",
-	"text/ecmascript",
-	"application/x-javascript",
-	"text/html",
-}
-
-var MediaContentTypes = [...]string{
-	"image/jpeg",
-	"image/png",
-	"image/bmp",
-	"image/gif",
-	"image/tiff",
-	"video/avi",
-	"video/mpeg",
-	"video/mp4",
-	"audio/mpeg",
-	"audio/wav",
-}
-
 const maxMultipartFormDataBytes = 10 * 1024 // 10Kb
 
 func (api *API) InitFile() {
@@ -502,7 +479,7 @@ func getFile(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	auditRec.Success()
 
-	writeFileResponse(info.Name, info.MimeType, info.Size, time.Unix(0, info.UpdateAt*int64(1000*1000)), *c.App.Config().ServiceSettings.WebserverMode, fileReader, forceDownload, w, r)
+	web.WriteFileResponse(info.Name, info.MimeType, info.Size, time.Unix(0, info.UpdateAt*int64(1000*1000)), *c.App.Config().ServiceSettings.WebserverMode, fileReader, forceDownload, w, r)
 }
 
 func getFileThumbnail(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -537,7 +514,7 @@ func getFileThumbnail(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 	defer fileReader.Close()
 
-	writeFileResponse(info.Name, ThumbnailImageType, 0, time.Unix(0, info.UpdateAt*int64(1000*1000)), *c.App.Config().ServiceSettings.WebserverMode, fileReader, forceDownload, w, r)
+	web.WriteFileResponse(info.Name, ThumbnailImageType, 0, time.Unix(0, info.UpdateAt*int64(1000*1000)), *c.App.Config().ServiceSettings.WebserverMode, fileReader, forceDownload, w, r)
 }
 
 func getFileLink(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -614,7 +591,7 @@ func getFilePreview(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 	defer fileReader.Close()
 
-	writeFileResponse(info.Name, PreviewImageType, 0, time.Unix(0, info.UpdateAt*int64(1000*1000)), *c.App.Config().ServiceSettings.WebserverMode, fileReader, forceDownload, w, r)
+	web.WriteFileResponse(info.Name, PreviewImageType, 0, time.Unix(0, info.UpdateAt*int64(1000*1000)), *c.App.Config().ServiceSettings.WebserverMode, fileReader, forceDownload, w, r)
 }
 
 func getFileInfo(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -681,64 +658,7 @@ func getPublicFile(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 	defer fileReader.Close()
 
-	writeFileResponse(info.Name, info.MimeType, info.Size, time.Unix(0, info.UpdateAt*int64(1000*1000)), *c.App.Config().ServiceSettings.WebserverMode, fileReader, false, w, r)
+	web.WriteFileResponse(info.Name, info.MimeType, info.Size, time.Unix(0, info.UpdateAt*int64(1000*1000)), *c.App.Config().ServiceSettings.WebserverMode, fileReader, false, w, r)
-}
-
-func writeFileResponse(filename string, contentType string, contentSize int64, lastModification time.Time, webserverMode string, fileReader io.ReadSeeker, forceDownload bool, w http.ResponseWriter, r *http.Request) {
-	w.Header().Set("Cache-Control", "private, no-cache")
-	w.Header().Set("X-Content-Type-Options", "nosniff")
-
-	if contentSize > 0 {
-		contentSizeStr := strconv.Itoa(int(contentSize))
-		if webserverMode == "gzip" {
-			w.Header().Set("X-Uncompressed-Content-Length", contentSizeStr)
-		} else {
-			w.Header().Set("Content-Length", contentSizeStr)
-		}
-	}
-
-	if contentType == "" {
-		contentType = "application/octet-stream"
-	} else {
-		for _, unsafeContentType := range UnsafeContentTypes {
-			if strings.HasPrefix(contentType, unsafeContentType) {
-				contentType = "text/plain"
-				break
-			}
-		}
-	}
-
-	w.Header().Set("Content-Type", contentType)
-
-	var toDownload bool
-	if forceDownload {
-		toDownload = true
-	} else {
-		isMediaType := false
-
-		for _, mediaContentType := range MediaContentTypes {
-			if strings.HasPrefix(contentType, mediaContentType) {
-				isMediaType = true
-				break
-			}
-		}
-
-		toDownload = !isMediaType
-	}
-
-	filename = url.PathEscape(filename)
-
-	if toDownload {
-		w.Header().Set("Content-Disposition", "attachment;filename=\""+filename+"\"; filename*=UTF-8''"+filename)
-	} else {
-		w.Header().Set("Content-Disposition", "inline;filename=\""+filename+"\"; filename*=UTF-8''"+filename)
-	}
-
-	// prevent file links from being embedded in iframes
-	w.Header().Set("X-Frame-Options", "DENY")
-	w.Header().Set("Content-Security-Policy", "Frame-ancestors 'none'")
-
-	http.ServeContent(w, r, filename, lastModification, fileReader)
 }
 
 func searchFilesInTeam(c *Context, w http.ResponseWriter, r *http.Request) {

api4/hosted_customer.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/mattermost/mattermost-server/v6/model"
 	"github.com/mattermost/mattermost-server/v6/shared/mlog"
+	"github.com/mattermost/mattermost-server/v6/shared/web"
 	"github.com/mattermost/mattermost-server/v6/utils"
 )
 
@@ -275,7 +276,7 @@ func selfHostedInvoicePDF(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	writeFileResponse(
+	web.WriteFileResponse(
 		filename,
 		"application/pdf",
 		int64(binary.Size(pdfData)),

api4/job.go

@@ -13,6 +13,7 @@ import (
 	"github.com/mattermost/mattermost-server/v6/audit"
 	"github.com/mattermost/mattermost-server/v6/model"
 	"github.com/mattermost/mattermost-server/v6/shared/mlog"
+	"github.com/mattermost/mattermost-server/v6/shared/web"
 )
 
 func (api *API) InitJob() {
@@ -100,7 +101,7 @@ func downloadJob(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	// We are able to pass 0 for content size due to the fact that Golang's serveContent (https://golang.org/src/net/http/fs.go)
 	// already sets that for us
-	writeFileResponse(fileName, FileMime, 0, time.Unix(0, job.LastActivityAt*int64(1000*1000)), *c.App.Config().ServiceSettings.WebserverMode, fileReader, true, w, r)
+	web.WriteFileResponse(fileName, FileMime, 0, time.Unix(0, job.LastActivityAt*int64(1000*1000)), *c.App.Config().ServiceSettings.WebserverMode, fileReader, true, w, r)
 }
 
 func createJob(c *Context, w http.ResponseWriter, r *http.Request) {

api4/system.go

@@ -22,6 +22,7 @@ import (
 	"github.com/mattermost/mattermost-server/v6/services/cache"
 	"github.com/mattermost/mattermost-server/v6/services/upgrader"
 	"github.com/mattermost/mattermost-server/v6/shared/mlog"
+	"github.com/mattermost/mattermost-server/v6/shared/web"
 )
 
 const (
@@ -122,7 +123,7 @@ func generateSupportPacket(c *Context, w http.ResponseWriter, r *http.Request) {
 	// Send the zip file back to client
 	// We are able to pass 0 for content size due to the fact that Golang's serveContent (https://golang.org/src/net/http/fs.go)
 	// already sets that for us
-	writeFileResponse(outputZipFilename, FileMime, 0, now, *c.App.Config().ServiceSettings.WebserverMode, fileBytesReader, true, w, r)
+	web.WriteFileResponse(outputZipFilename, FileMime, 0, now, *c.App.Config().ServiceSettings.WebserverMode, fileBytesReader, true, w, r)
 }
 
 func getSystemPing(c *Context, w http.ResponseWriter, r *http.Request) {

shared/web/files.go

@@ -0,0 +1,92 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package web
+
+import (
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var UnsafeContentTypes = [...]string{
+	"application/javascript",
+	"application/ecmascript",
+	"text/javascript",
+	"text/ecmascript",
+	"application/x-javascript",
+	"text/html",
+}
+
+var MediaContentTypes = [...]string{
+	"image/jpeg",
+	"image/png",
+	"image/bmp",
+	"image/gif",
+	"image/tiff",
+	"video/avi",
+	"video/mpeg",
+	"video/mp4",
+	"audio/mpeg",
+	"audio/wav",
+}
+
+func WriteFileResponse(filename string, contentType string, contentSize int64, lastModification time.Time, webserverMode string, fileReader io.ReadSeeker, forceDownload bool, w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Cache-Control", "private, no-cache")
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+
+	if contentSize > 0 {
+		contentSizeStr := strconv.Itoa(int(contentSize))
+		if webserverMode == "gzip" {
+			w.Header().Set("X-Uncompressed-Content-Length", contentSizeStr)
+		} else {
+			w.Header().Set("Content-Length", contentSizeStr)
+		}
+	}
+
+	if contentType == "" {
+		contentType = "application/octet-stream"
+	} else {
+		for _, unsafeContentType := range UnsafeContentTypes {
+			if strings.HasPrefix(contentType, unsafeContentType) {
+				contentType = "text/plain"
+				break
+			}
+		}
+	}
+
+	w.Header().Set("Content-Type", contentType)
+
+	var toDownload bool
+	if forceDownload {
+		toDownload = true
+	} else {
+		isMediaType := false
+
+		for _, mediaContentType := range MediaContentTypes {
+			if strings.HasPrefix(contentType, mediaContentType) {
+				isMediaType = true
+				break
+			}
+		}
+
+		toDownload = !isMediaType
+	}
+
+	filename = url.PathEscape(filename)
+
+	if toDownload {
+		w.Header().Set("Content-Disposition", "attachment;filename=\""+filename+"\"; filename*=UTF-8''"+filename)
+	} else {
+		w.Header().Set("Content-Disposition", "inline;filename=\""+filename+"\"; filename*=UTF-8''"+filename)
+	}
+
+	// prevent file links from being embedded in iframes
+	w.Header().Set("X-Frame-Options", "DENY")
+	w.Header().Set("Content-Security-Policy", "Frame-ancestors 'none'")
+
+	http.ServeContent(w, r, filename, lastModification, fileReader)
+}