Add support for 3D/CAD file formats preview (#34794)

Fix #34775 

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/git/blob.go

@@ -22,17 +22,22 @@ func (b *Blob) Name() string {
 	return b.name
 }
 
-// GetBlobContent Gets the limited content of the blob as raw text
-func (b *Blob) GetBlobContent(limit int64) (string, error) {
+// GetBlobBytes Gets the limited content of the blob
+func (b *Blob) GetBlobBytes(limit int64) ([]byte, error) {
 	if limit <= 0 {
-		return "", nil
+		return nil, nil
 	}
 	dataRc, err := b.DataAsync()
 	if err != nil {
-		return "", err
+		return nil, err
 	}
 	defer dataRc.Close()
-	buf, err := util.ReadWithLimit(dataRc, int(limit))
+	return util.ReadWithLimit(dataRc, int(limit))
+}
+
+// GetBlobContent Gets the limited content of the blob as raw text
+func (b *Blob) GetBlobContent(limit int64) (string, error) {
+	buf, err := b.GetBlobBytes(limit)
 	return string(buf), err
 }
 
@@ -99,11 +104,9 @@ loop:
 
 // GuessContentType guesses the content type of the blob.
 func (b *Blob) GuessContentType() (typesniffer.SniffedType, error) {
-	r, err := b.DataAsync()
+	buf, err := b.GetBlobBytes(typesniffer.SniffContentSize)
 	if err != nil {
 		return typesniffer.SniffedType{}, err
 	}
-	defer r.Close()
-
-	return typesniffer.DetectContentTypeFromReader(r)
+	return typesniffer.DetectContentType(buf), nil
 }

modules/markup/console/console.go

@@ -6,13 +6,14 @@ package console
 import (
 	"bytes"
 	"io"
-	"path"
+	"unicode/utf8"
 
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
+	"code.gitea.io/gitea/modules/util"
 
 	trend "github.com/buildkite/terminal-to-html/v3"
-	"github.com/go-enry/go-enry/v2"
 )
 
 func init() {
@@ -22,6 +23,8 @@ func init() {
 // Renderer implements markup.Renderer
 type Renderer struct{}
 
+var _ markup.RendererContentDetector = (*Renderer)(nil)
+
 // Name implements markup.Renderer
 func (Renderer) Name() string {
 	return "console"
@@ -40,15 +43,36 @@ func (Renderer) SanitizerRules() []setting.MarkupSanitizerRule {
 }
 
 // CanRender implements markup.RendererContentDetector
-func (Renderer) CanRender(filename string, input io.Reader) bool {
-	buf, err := io.ReadAll(input)
-	if err != nil {
+func (Renderer) CanRender(filename string, sniffedType typesniffer.SniffedType, prefetchBuf []byte) bool {
+	if !sniffedType.IsTextPlain() {
 		return false
 	}
-	if enry.GetLanguage(path.Base(filename), buf) != enry.OtherLanguage {
+
+	s := util.UnsafeBytesToString(prefetchBuf)
+	rs := []rune(s)
+	cnt := 0
+	firstErrPos := -1
+	isCtrlSep := func(p int) bool {
+		return p < len(rs) && (rs[p] == ';' || rs[p] == 'm')
+	}
+	for i, c := range rs {
+		if c == 0 {
+			return false
+		}
+		if c == '\x1b' {
+			match := i+1 < len(rs) && rs[i+1] == '['
+			if match && (isCtrlSep(i+2) || isCtrlSep(i+3) || isCtrlSep(i+4) || isCtrlSep(i+5)) {
+				cnt++
+			}
+		}
+		if c == utf8.RuneError && firstErrPos == -1 {
+			firstErrPos = i
+		}
+	}
+	if firstErrPos != -1 && firstErrPos != len(rs)-1 {
 		return false
 	}
-	return bytes.ContainsRune(buf, '\x1b')
+	return cnt >= 2 // only render it as console output if there are at least two escape sequences
 }
 
 // Render renders terminal colors to HTML with all specific handling stuff.

modules/markup/console/console_test.go

@@ -8,23 +8,39 @@ import (
 	"testing"
 
 	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/typesniffer"
 
 	"github.com/stretchr/testify/assert"
 )
 
 func TestRenderConsole(t *testing.T) {
-	var render Renderer
-	kases := map[string]string{
-		"\x1b[37m\x1b[40mnpm\x1b[0m \x1b[0m\x1b[32minfo\x1b[0m \x1b[0m\x1b[35mit worked if it ends with\x1b[0m ok": "<span class=\"term-fg37 term-bg40\">npm</span> <span class=\"term-fg32\">info</span> <span class=\"term-fg35\">it worked if it ends with</span> ok",
+	cases := []struct {
+		input    string
+		expected string
+	}{
+		{"\x1b[37m\x1b[40mnpm\x1b[0m \x1b[0m\x1b[32minfo\x1b[0m \x1b[0m\x1b[35mit worked if it ends with\x1b[0m ok", `<span class="term-fg37 term-bg40">npm</span> <span class="term-fg32">info</span> <span class="term-fg35">it worked if it ends with</span> ok`},
+		{"\x1b[1;2m \x1b[123m 啊", `<span class="term-fg2">  啊</span>`},
+		{"\x1b[1;2m \x1b[123m \xef", `<span class="term-fg2">  <20></span>`},
+		{"\x1b[1;2m \x1b[123m \xef \xef", ``},
+		{"\x1b[12", ``},
+		{"\x1b[1", ``},
+		{"\x1b[FOO\x1b[", ``},
+		{"\x1b[mFOO\x1b[m", `FOO`},
 	}
 
-	for k, v := range kases {
+	var render Renderer
+	for i, c := range cases {
 		var buf strings.Builder
-		canRender := render.CanRender("test", strings.NewReader(k))
-		assert.True(t, canRender)
+		st := typesniffer.DetectContentType([]byte(c.input))
+		canRender := render.CanRender("test", st, []byte(c.input))
+		if c.expected == "" {
+			assert.False(t, canRender, "case %d: expected not to render", i)
+			continue
+		}
 
-		err := render.Render(markup.NewRenderContext(t.Context()), strings.NewReader(k), &buf)
+		assert.True(t, canRender)
+		err := render.Render(markup.NewRenderContext(t.Context()), strings.NewReader(c.input), &buf)
 		assert.NoError(t, err)
-		assert.Equal(t, v, buf.String())
+		assert.Equal(t, c.expected, buf.String())
 	}
 }

modules/markup/renderer.go

@@ -4,12 +4,12 @@
 package markup
 
 import (
-	"bytes"
 	"io"
 	"path"
 	"strings"
 
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
 )
 
 // Renderer defines an interface for rendering markup file to HTML
@@ -37,7 +37,7 @@ type ExternalRenderer interface {
 // RendererContentDetector detects if the content can be rendered
 // by specified renderer
 type RendererContentDetector interface {
-	CanRender(filename string, input io.Reader) bool
+	CanRender(filename string, sniffedType typesniffer.SniffedType, prefetchBuf []byte) bool
 }
 
 var (
@@ -60,13 +60,9 @@ func GetRendererByFileName(filename string) Renderer {
 }
 
 // DetectRendererType detects the markup type of the content
-func DetectRendererType(filename string, input io.Reader) string {
-	buf, err := io.ReadAll(input)
-	if err != nil {
-		return ""
-	}
+func DetectRendererType(filename string, sniffedType typesniffer.SniffedType, prefetchBuf []byte) string {
 	for _, renderer := range renderers {
-		if detector, ok := renderer.(RendererContentDetector); ok && detector.CanRender(filename, bytes.NewReader(buf)) {
+		if detector, ok := renderer.(RendererContentDetector); ok && detector.CanRender(filename, sniffedType, prefetchBuf) {
 			return renderer.Name()
 		}
 	}

modules/typesniffer/typesniffer.go

@@ -6,18 +6,14 @@ package typesniffer
 import (
 	"bytes"
 	"encoding/binary"
-	"fmt"
-	"io"
 	"net/http"
 	"regexp"
 	"slices"
 	"strings"
-
-	"code.gitea.io/gitea/modules/util"
+	"sync"
 )
 
-// Use at most this many bytes to determine Content Type.
-const sniffLen = 1024
+const SniffContentSize = 1024
 
 const (
 	MimeTypeImageSvg  = "image/svg+xml"
@@ -26,22 +22,30 @@ const (
 	MimeTypeApplicationOctetStream = "application/octet-stream"
 )
 
-var (
-	svgComment       = regexp.MustCompile(`(?s)<!--.*?-->`)
-	svgTagRegex      = regexp.MustCompile(`(?si)\A\s*(?:(<!DOCTYPE\s+svg([\s:]+.*?>|>))\s*)*<svg\b`)
-	svgTagInXMLRegex = regexp.MustCompile(`(?si)\A<\?xml\b.*?\?>\s*(?:(<!DOCTYPE\s+svg([\s:]+.*?>|>))\s*)*<svg\b`)
-)
+var globalVars = sync.OnceValue(func() (ret struct {
+	svgComment, svgTagRegex, svgTagInXMLRegex *regexp.Regexp
+},
+) {
+	ret.svgComment = regexp.MustCompile(`(?s)<!--.*?-->`)
+	ret.svgTagRegex = regexp.MustCompile(`(?si)\A\s*(?:(<!DOCTYPE\s+svg([\s:]+.*?>|>))\s*)*<svg\b`)
+	ret.svgTagInXMLRegex = regexp.MustCompile(`(?si)\A<\?xml\b.*?\?>\s*(?:(<!DOCTYPE\s+svg([\s:]+.*?>|>))\s*)*<svg\b`)
+	return ret
+})
 
-// SniffedType contains information about a blobs type.
+// SniffedType contains information about a blob's type.
 type SniffedType struct {
 	contentType string
 }
 
-// IsText etects if content format is plain text.
+// IsText detects if the content format is text family, including text/plain, text/html, text/css, etc.
 func (ct SniffedType) IsText() bool {
 	return strings.Contains(ct.contentType, "text/")
 }
 
+func (ct SniffedType) IsTextPlain() bool {
+	return strings.Contains(ct.contentType, "text/plain")
+}
+
 // IsImage detects if data is an image format
 func (ct SniffedType) IsImage() bool {
 	return strings.Contains(ct.contentType, "image/")
@@ -57,12 +61,12 @@ func (ct SniffedType) IsPDF() bool {
 	return strings.Contains(ct.contentType, "application/pdf")
 }
 
-// IsVideo detects if data is an video format
+// IsVideo detects if data is a video format
 func (ct SniffedType) IsVideo() bool {
 	return strings.Contains(ct.contentType, "video/")
 }
 
-// IsAudio detects if data is an video format
+// IsAudio detects if data is a video format
 func (ct SniffedType) IsAudio() bool {
 	return strings.Contains(ct.contentType, "audio/")
 }
@@ -103,33 +107,34 @@ func detectFileTypeBox(data []byte) (brands []string, found bool) {
 	return brands, true
 }
 
-// DetectContentType extends http.DetectContentType with more content types. Defaults to text/unknown if input is empty.
+// DetectContentType extends http.DetectContentType with more content types. Defaults to text/plain if input is empty.
 func DetectContentType(data []byte) SniffedType {
 	if len(data) == 0 {
-		return SniffedType{"text/unknown"}
+		return SniffedType{"text/plain"}
 	}
 
 	ct := http.DetectContentType(data)
 
-	if len(data) > sniffLen {
-		data = data[:sniffLen]
+	if len(data) > SniffContentSize {
+		data = data[:SniffContentSize]
 	}
 
+	vars := globalVars()
 	// SVG is unsupported by http.DetectContentType, https://github.com/golang/go/issues/15888
 	detectByHTML := strings.Contains(ct, "text/plain") || strings.Contains(ct, "text/html")
 	detectByXML := strings.Contains(ct, "text/xml")
 	if detectByHTML || detectByXML {
-		dataProcessed := svgComment.ReplaceAll(data, nil)
+		dataProcessed := vars.svgComment.ReplaceAll(data, nil)
 		dataProcessed = bytes.TrimSpace(dataProcessed)
-		if detectByHTML && svgTagRegex.Match(dataProcessed) ||
-			detectByXML && svgTagInXMLRegex.Match(dataProcessed) {
+		if detectByHTML && vars.svgTagRegex.Match(dataProcessed) ||
+			detectByXML && vars.svgTagInXMLRegex.Match(dataProcessed) {
 			ct = MimeTypeImageSvg
 		}
 	}
 
 	if strings.HasPrefix(ct, "audio/") && bytes.HasPrefix(data, []byte("ID3")) {
 		// The MP3 detection is quite inaccurate, any content with "ID3" prefix will result in "audio/mpeg".
-		// So remove the "ID3" prefix and detect again, if result is text, then it must be text content.
+		// So remove the "ID3" prefix and detect again, then if the result is "text", it must be text content.
 		// This works especially because audio files contain many unprintable/invalid characters like `0x00`
 		ct2 := http.DetectContentType(data[3:])
 		if strings.HasPrefix(ct2, "text/") {
@@ -155,15 +160,3 @@ func DetectContentType(data []byte) SniffedType {
 	}
 	return SniffedType{ct}
 }
-
-// DetectContentTypeFromReader guesses the content type contained in the reader.
-func DetectContentTypeFromReader(r io.Reader) (SniffedType, error) {
-	buf := make([]byte, sniffLen)
-	n, err := util.ReadAtMost(r, buf)
-	if err != nil {
-		return SniffedType{}, fmt.Errorf("DetectContentTypeFromReader io error: %w", err)
-	}
-	buf = buf[:n]
-
-	return DetectContentType(buf), nil
-}

modules/typesniffer/typesniffer_test.go

@@ -4,7 +4,6 @@
 package typesniffer
 
 import (
-	"bytes"
 	"encoding/base64"
 	"encoding/hex"
 	"strings"
@@ -17,7 +16,7 @@ func TestDetectContentTypeLongerThanSniffLen(t *testing.T) {
 	// Pre-condition: Shorter than sniffLen detects SVG.
 	assert.Equal(t, "image/svg+xml", DetectContentType([]byte(`<!-- Comment --><svg></svg>`)).contentType)
 	// Longer than sniffLen detects something else.
-	assert.NotEqual(t, "image/svg+xml", DetectContentType([]byte(`<!-- `+strings.Repeat("x", sniffLen)+` --><svg></svg>`)).contentType)
+	assert.NotEqual(t, "image/svg+xml", DetectContentType([]byte(`<!-- `+strings.Repeat("x", SniffContentSize)+` --><svg></svg>`)).contentType)
 }
 
 func TestIsTextFile(t *testing.T) {
@@ -116,22 +115,13 @@ func TestIsAudio(t *testing.T) {
 	assert.True(t, DetectContentType([]byte("ID3Toy\n====\t* hi 🌞, ..."+"🌛"[0:2])).IsText()) // test ID3 tag with incomplete UTF8 char
 }
 
-func TestDetectContentTypeFromReader(t *testing.T) {
-	mp3, _ := base64.StdEncoding.DecodeString("SUQzBAAAAAABAFRYWFgAAAASAAADbWFqb3JfYnJhbmQAbXA0MgBUWFhYAAAAEQAAA21pbm9yX3Zl")
-	st, err := DetectContentTypeFromReader(bytes.NewReader(mp3))
-	assert.NoError(t, err)
-	assert.True(t, st.IsAudio())
-}
-
 func TestDetectContentTypeOgg(t *testing.T) {
 	oggAudio, _ := hex.DecodeString("4f67675300020000000000000000352f0000000000007dc39163011e01766f72626973000000000244ac0000000000000071020000000000b8014f6767530000")
-	st, err := DetectContentTypeFromReader(bytes.NewReader(oggAudio))
-	assert.NoError(t, err)
+	st := DetectContentType(oggAudio)
 	assert.True(t, st.IsAudio())
 
 	oggVideo, _ := hex.DecodeString("4f676753000200000000000000007d9747ef000000009b59daf3012a807468656f7261030201001e00110001e000010e00020000001e00000001000001000001")
-	st, err = DetectContentTypeFromReader(bytes.NewReader(oggVideo))
-	assert.NoError(t, err)
+	st = DetectContentType(oggVideo)
 	assert.True(t, st.IsVideo())
 }
 

package-lock.json

@@ -40,6 +40,7 @@
         "minimatch": "10.0.2",
         "monaco-editor": "0.52.2",
         "monaco-editor-webpack-plugin": "7.1.0",
+        "online-3d-viewer": "0.16.0",
         "pdfobject": "2.3.1",
         "perfect-debounce": "1.0.0",
         "postcss": "8.5.5",
@@ -2026,6 +2027,16 @@
         "vue": "^3.2.29"
       }
     },
+    "node_modules/@simonwep/pickr": {
+      "version": "1.9.0",
+      "resolved": "https://registry.npmmirror.com/@simonwep/pickr/-/pickr-1.9.0.tgz",
+      "integrity": "sha512-oEYvv15PyfZzjoAzvXYt3UyNGwzsrpFxLaZKzkOSd0WYBVwLd19iJerePDONxC1iF6+DpcswPdLIM2KzCJuYFg==",
+      "license": "MIT",
+      "dependencies": {
+        "core-js": "3.32.2",
+        "nanopop": "2.3.0"
+      }
+    },
     "node_modules/@stoplight/better-ajv-errors": {
       "version": "1.0.3",
       "resolved": "https://registry.npmjs.org/@stoplight/better-ajv-errors/-/better-ajv-errors-1.0.3.tgz",
@@ -5337,6 +5348,17 @@
       "integrity": "sha512-1NB+BKqhtNipMsov4xI/NnhCKp9XG9NamYp5PVm9klAT0fsrNPjaFICsCFhNhwZJKNh7zB/3q8qXz0E9oaMNtQ==",
       "license": "MIT"
     },
+    "node_modules/core-js": {
+      "version": "3.32.2",
+      "resolved": "https://registry.npmmirror.com/core-js/-/core-js-3.32.2.tgz",
+      "integrity": "sha512-pxXSw1mYZPDGvTQqEc5vgIb83jGQKFGYWY76z4a7weZXUolw3G+OvpZqSRcfYOoOVUQJYEPsWeQK8pKEnUtWxQ==",
+      "hasInstallScript": true,
+      "license": "MIT",
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/core-js"
+      }
+    },
     "node_modules/core-js-compat": {
       "version": "3.43.0",
       "resolved": "https://registry.npmjs.org/core-js-compat/-/core-js-compat-3.43.0.tgz",
@@ -7721,6 +7743,12 @@
         }
       }
     },
+    "node_modules/fflate": {
+      "version": "0.8.2",
+      "resolved": "https://registry.npmmirror.com/fflate/-/fflate-0.8.2.tgz",
+      "integrity": "sha512-cPJU47OaAoCbg0pBvzsgpTPhmhqI5eJjh/JIu8tPj5q+T7iLvW/JAYUqmE7KOB4R1ZyEhzBaIQpQpardBF5z8A==",
+      "license": "MIT"
+    },
     "node_modules/file-entry-cache": {
       "version": "6.0.1",
       "resolved": "https://registry.npmjs.org/file-entry-cache/-/file-entry-cache-6.0.1.tgz",
@@ -10285,6 +10313,12 @@
         "node": "^10 || ^12 || ^13.7 || ^14 || >=15.0.1"
       }
     },
+    "node_modules/nanopop": {
+      "version": "2.3.0",
+      "resolved": "https://registry.npmmirror.com/nanopop/-/nanopop-2.3.0.tgz",
+      "integrity": "sha512-fzN+T2K7/Ah25XU02MJkPZ5q4Tj5FpjmIYq4rvoHX4yb16HzFdCO6JxFFn5Y/oBhQ8no8fUZavnyIv9/+xkBBw==",
+      "license": "MIT"
+    },
     "node_modules/napi-postinstall": {
       "version": "0.2.4",
       "resolved": "https://registry.npmjs.org/napi-postinstall/-/napi-postinstall-0.2.4.tgz",
@@ -10525,6 +10559,17 @@
         "wrappy": "1"
       }
     },
+    "node_modules/online-3d-viewer": {
+      "version": "0.16.0",
+      "resolved": "https://registry.npmmirror.com/online-3d-viewer/-/online-3d-viewer-0.16.0.tgz",
+      "integrity": "sha512-Mcmo41TM3K+svlMDRH8ySKSY2e8s7Sssdb5U9LV3gkFKVWGGuS304Vk5gqxopAJbE72DpsC67Ve3YNtcAuROwQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@simonwep/pickr": "1.9.0",
+        "fflate": "0.8.2",
+        "three": "0.176.0"
+      }
+    },
     "node_modules/optionator": {
       "version": "0.9.4",
       "resolved": "https://registry.npmjs.org/optionator/-/optionator-0.9.4.tgz",
@@ -13193,6 +13238,12 @@
         "node": ">=0.8"
       }
     },
+    "node_modules/three": {
+      "version": "0.176.0",
+      "resolved": "https://registry.npmmirror.com/three/-/three-0.176.0.tgz",
+      "integrity": "sha512-PWRKYWQo23ojf9oZSlRGH8K09q7nRSWx6LY/HF/UUrMdYgN9i1e2OwJYHoQjwc6HF/4lvvYLC5YC1X8UJL2ZpA==",
+      "license": "MIT"
+    },
     "node_modules/throttle-debounce": {
       "version": "5.0.2",
       "resolved": "https://registry.npmjs.org/throttle-debounce/-/throttle-debounce-5.0.2.tgz",

package.json

@@ -39,6 +39,7 @@
     "minimatch": "10.0.2",
     "monaco-editor": "0.52.2",
     "monaco-editor-webpack-plugin": "7.1.0",
+    "online-3d-viewer": "0.16.0",
     "pdfobject": "2.3.1",
     "perfect-debounce": "1.0.0",
     "postcss": "8.5.5",

routers/web/repo/editor.go

@@ -244,7 +244,7 @@ func editFileOpenExisting(ctx *context.Context) (prefetch []byte, dataRc io.Read
 		return nil, nil, nil
 	}
 
-	if fInfo.isLFSFile {
+	if fInfo.isLFSFile() {
 		lfsLock, err := git_model.GetTreePathLock(ctx, ctx.Repo.Repository.ID, ctx.Repo.TreePath)
 		if err != nil {
 			_ = dataRc.Close()
@@ -298,7 +298,7 @@ func EditFile(ctx *context.Context) {
 		ctx.Data["FileSize"] = fInfo.fileSize
 
 		// Only some file types are editable online as text.
-		if fInfo.isLFSFile {
+		if fInfo.isLFSFile() {
 			ctx.Data["NotEditableReason"] = ctx.Tr("repo.editor.cannot_edit_lfs_files")
 		} else if !fInfo.st.IsRepresentableAsText() {
 			ctx.Data["NotEditableReason"] = ctx.Tr("repo.editor.cannot_edit_non_text_files")

routers/web/repo/setting/lfs.go

@@ -267,8 +267,10 @@ func LFSFileGet(ctx *context.Context) {
 	buf = buf[:n]
 
 	st := typesniffer.DetectContentType(buf)
+	// FIXME: there is no IsPlainText set, but template uses it
 	ctx.Data["IsTextFile"] = st.IsText()
 	ctx.Data["FileSize"] = meta.Size
+	// FIXME: the last field is the URL-base64-encoded filename, it should not be "direct"
 	ctx.Data["RawFileLink"] = fmt.Sprintf("%s%s/%s.git/info/lfs/objects/%s/%s", setting.AppURL, url.PathEscape(ctx.Repo.Repository.OwnerName), url.PathEscape(ctx.Repo.Repository.Name), url.PathEscape(meta.Oid), "direct")
 	switch {
 	case st.IsRepresentableAsText():
@@ -309,8 +311,6 @@ func LFSFileGet(ctx *context.Context) {
 		}
 		ctx.Data["LineNums"] = gotemplate.HTML(output.String())
 
-	case st.IsPDF():
-		ctx.Data["IsPDFFile"] = true
 	case st.IsVideo():
 		ctx.Data["IsVideoFile"] = true
 	case st.IsAudio():

routers/web/repo/view.go

@@ -59,60 +59,63 @@ const (
 )
 
 type fileInfo struct {
-	isTextFile bool
-	isLFSFile  bool
-	fileSize   int64
-	lfsMeta    *lfs.Pointer
-	st         typesniffer.SniffedType
+	fileSize int64
+	lfsMeta  *lfs.Pointer
+	st       typesniffer.SniffedType
 }
 
-func getFileReader(ctx gocontext.Context, repoID int64, blob *git.Blob) ([]byte, io.ReadCloser, *fileInfo, error) {
-	dataRc, err := blob.DataAsync()
+func (fi *fileInfo) isLFSFile() bool {
+	return fi.lfsMeta != nil && fi.lfsMeta.Oid != ""
+}
+
+func getFileReader(ctx gocontext.Context, repoID int64, blob *git.Blob) (buf []byte, dataRc io.ReadCloser, fi *fileInfo, err error) {
+	dataRc, err = blob.DataAsync()
 	if err != nil {
 		return nil, nil, nil, err
 	}
 
-	buf := make([]byte, 1024)
+	const prefetchSize = lfs.MetaFileMaxSize
+
+	buf = make([]byte, prefetchSize)
 	n, _ := util.ReadAtMost(dataRc, buf)
 	buf = buf[:n]
 
-	st := typesniffer.DetectContentType(buf)
-	isTextFile := st.IsText()
+	fi = &fileInfo{fileSize: blob.Size(), st: typesniffer.DetectContentType(buf)}
 
 	// FIXME: what happens when README file is an image?
-	if !isTextFile || !setting.LFS.StartServer {
-		return buf, dataRc, &fileInfo{isTextFile, false, blob.Size(), nil, st}, nil
+	if !fi.st.IsText() || !setting.LFS.StartServer {
+		return buf, dataRc, fi, nil
 	}
 
 	pointer, _ := lfs.ReadPointerFromBuffer(buf)
-	if !pointer.IsValid() { // fallback to plain file
-		return buf, dataRc, &fileInfo{isTextFile, false, blob.Size(), nil, st}, nil
+	if !pointer.IsValid() { // fallback to a plain file
+		return buf, dataRc, fi, nil
 	}
 
 	meta, err := git_model.GetLFSMetaObjectByOid(ctx, repoID, pointer.Oid)
-	if err != nil { // fallback to plain file
+	if err != nil { // fallback to a plain file
 		log.Warn("Unable to access LFS pointer %s in repo %d: %v", pointer.Oid, repoID, err)
-		return buf, dataRc, &fileInfo{isTextFile, false, blob.Size(), nil, st}, nil
+		return buf, dataRc, fi, nil
 	}
 
-	dataRc.Close()
-
+	// close the old dataRc and open the real LFS target
+	_ = dataRc.Close()
 	dataRc, err = lfs.ReadMetaObject(pointer)
 	if err != nil {
 		return nil, nil, nil, err
 	}
 
-	buf = make([]byte, 1024)
+	buf = make([]byte, prefetchSize)
 	n, err = util.ReadAtMost(dataRc, buf)
 	if err != nil {
-		dataRc.Close()
-		return nil, nil, nil, err
+		_ = dataRc.Close()
+		return nil, nil, fi, err
 	}
 	buf = buf[:n]
-
-	st = typesniffer.DetectContentType(buf)
-
-	return buf, dataRc, &fileInfo{st.IsText(), true, meta.Size, &meta.Pointer, st}, nil
+	fi.st = typesniffer.DetectContentType(buf)
+	fi.fileSize = blob.Size()
+	fi.lfsMeta = &meta.Pointer
+	return buf, dataRc, fi, nil
 }
 
 func loadLatestCommitData(ctx *context.Context, latestCommit *git.Commit) bool {

routers/web/repo/view_file.go

@@ -23,6 +23,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
 	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/services/context"
 	issue_service "code.gitea.io/gitea/services/issue"
@@ -40,7 +41,128 @@ func prepareLatestCommitInfo(ctx *context.Context) bool {
 	return loadLatestCommitData(ctx, commit)
 }
 
-func prepareToRenderFile(ctx *context.Context, entry *git.TreeEntry) {
+func prepareFileViewLfsAttrs(ctx *context.Context) (*attribute.Attributes, bool) {
+	attrsMap, err := attribute.CheckAttributes(ctx, ctx.Repo.GitRepo, ctx.Repo.CommitID, attribute.CheckAttributeOpts{
+		Filenames:  []string{ctx.Repo.TreePath},
+		Attributes: []string{attribute.LinguistGenerated, attribute.LinguistVendored, attribute.LinguistLanguage, attribute.GitlabLanguage},
+	})
+	if err != nil {
+		ctx.ServerError("attribute.CheckAttributes", err)
+		return nil, false
+	}
+	attrs := attrsMap[ctx.Repo.TreePath]
+	if attrs == nil {
+		// this case shouldn't happen, just in case.
+		setting.PanicInDevOrTesting("no attributes found for %s", ctx.Repo.TreePath)
+		attrs = attribute.NewAttributes()
+	}
+	ctx.Data["IsVendored"], ctx.Data["IsGenerated"] = attrs.GetVendored().Value(), attrs.GetGenerated().Value()
+	return attrs, true
+}
+
+func handleFileViewRenderMarkup(ctx *context.Context, filename string, sniffedType typesniffer.SniffedType, prefetchBuf []byte, utf8Reader io.Reader) bool {
+	markupType := markup.DetectMarkupTypeByFileName(filename)
+	if markupType == "" {
+		markupType = markup.DetectRendererType(filename, sniffedType, prefetchBuf)
+	}
+	if markupType == "" {
+		return false
+	}
+
+	ctx.Data["HasSourceRenderedToggle"] = true
+
+	if ctx.FormString("display") == "source" {
+		return false
+	}
+
+	ctx.Data["MarkupType"] = markupType
+	metas := ctx.Repo.Repository.ComposeRepoFileMetas(ctx)
+	metas["RefTypeNameSubURL"] = ctx.Repo.RefTypeNameSubURL()
+	rctx := renderhelper.NewRenderContextRepoFile(ctx, ctx.Repo.Repository, renderhelper.RepoFileOptions{
+		CurrentRefPath:  ctx.Repo.RefTypeNameSubURL(),
+		CurrentTreePath: path.Dir(ctx.Repo.TreePath),
+	}).
+		WithMarkupType(markupType).
+		WithRelativePath(ctx.Repo.TreePath).
+		WithMetas(metas)
+
+	var err error
+	ctx.Data["EscapeStatus"], ctx.Data["FileContent"], err = markupRender(ctx, rctx, utf8Reader)
+	if err != nil {
+		ctx.ServerError("Render", err)
+		return true
+	}
+	// to prevent iframe from loading third-party url
+	ctx.Resp.Header().Add("Content-Security-Policy", "frame-src 'self'")
+	return true
+}
+
+func handleFileViewRenderSource(ctx *context.Context, filename string, attrs *attribute.Attributes, fInfo *fileInfo, utf8Reader io.Reader) bool {
+	if ctx.FormString("display") == "rendered" || !fInfo.st.IsRepresentableAsText() {
+		return false
+	}
+
+	if !fInfo.st.IsText() {
+		if ctx.FormString("display") == "" {
+			// not text but representable as text, e.g. SVG
+			// since there is no "display" is specified, let other renders to handle
+			return false
+		}
+		ctx.Data["HasSourceRenderedToggle"] = true
+	}
+
+	buf, _ := io.ReadAll(utf8Reader)
+	// The Open Group Base Specification: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html
+	//   empty: 0 lines; "a": 1 incomplete-line; "a\n": 1 line; "a\nb": 1 line, 1 incomplete-line;
+	// Gitea uses the definition (like most modern editors):
+	//   empty: 0 lines; "a": 1 line; "a\n": 2 lines; "a\nb": 2 lines;
+	//   When rendering, the last empty line is not rendered in UI, while the line-number is still counted, to tell users that the file contains a trailing EOL.
+	//   To make the UI more consistent, it could use an icon mark to indicate that there is no trailing EOL, and show line-number as the rendered lines.
+	// This NumLines is only used for the display on the UI: "xxx lines"
+	if len(buf) == 0 {
+		ctx.Data["NumLines"] = 0
+	} else {
+		ctx.Data["NumLines"] = bytes.Count(buf, []byte{'\n'}) + 1
+	}
+
+	language := attrs.GetLanguage().Value()
+	fileContent, lexerName, err := highlight.File(filename, language, buf)
+	ctx.Data["LexerName"] = lexerName
+	if err != nil {
+		log.Error("highlight.File failed, fallback to plain text: %v", err)
+		fileContent = highlight.PlainText(buf)
+	}
+	status := &charset.EscapeStatus{}
+	statuses := make([]*charset.EscapeStatus, len(fileContent))
+	for i, line := range fileContent {
+		statuses[i], fileContent[i] = charset.EscapeControlHTML(line, ctx.Locale)
+		status = status.Or(statuses[i])
+	}
+	ctx.Data["EscapeStatus"] = status
+	ctx.Data["FileContent"] = fileContent
+	ctx.Data["LineEscapeStatus"] = statuses
+	return true
+}
+
+func handleFileViewRenderImage(ctx *context.Context, fInfo *fileInfo, prefetchBuf []byte) bool {
+	if !fInfo.st.IsImage() {
+		return false
+	}
+	if fInfo.st.IsSvgImage() && !setting.UI.SVG.Enabled {
+		return false
+	}
+	if fInfo.st.IsSvgImage() {
+		ctx.Data["HasSourceRenderedToggle"] = true
+	} else {
+		img, _, err := image.DecodeConfig(bytes.NewReader(prefetchBuf))
+		if err == nil { // ignore the error for the formats that are not supported by image.DecodeConfig
+			ctx.Data["ImageSize"] = fmt.Sprintf("%dx%dpx", img.Width, img.Height)
+		}
+	}
+	return true
+}
+
+func prepareFileView(ctx *context.Context, entry *git.TreeEntry) {
 	ctx.Data["IsViewFile"] = true
 	ctx.Data["HideRepoInfo"] = true
 
@@ -86,11 +208,8 @@ func prepareToRenderFile(ctx *context.Context, entry *git.TreeEntry) {
 		}
 	}
 
-	isDisplayingSource := ctx.FormString("display") == "source"
-	isDisplayingRendered := !isDisplayingSource
-
 	// Don't call any other repository functions depends on git.Repository until the dataRc closed to
-	// avoid create unnecessary temporary cat file.
+	// avoid creating an unnecessary temporary cat file.
 	buf, dataRc, fInfo, err := getFileReader(ctx, ctx.Repo.Repository.ID, blob)
 	if err != nil {
 		ctx.ServerError("getFileReader", err)
@@ -98,207 +217,62 @@ func prepareToRenderFile(ctx *context.Context, entry *git.TreeEntry) {
 	}
 	defer dataRc.Close()
 
-	if fInfo.isLFSFile {
+	if fInfo.isLFSFile() {
 		ctx.Data["RawFileLink"] = ctx.Repo.RepoLink + "/media/" + ctx.Repo.RefTypeNameSubURL() + "/" + util.PathEscapeSegments(ctx.Repo.TreePath)
 	}
 
-	isRepresentableAsText := fInfo.st.IsRepresentableAsText()
-	if !isRepresentableAsText {
-		// If we can't show plain text, always try to render.
-		isDisplayingSource = false
-		isDisplayingRendered = true
+	if !prepareFileViewEditorButtons(ctx) {
+		return
 	}
-	ctx.Data["IsLFSFile"] = fInfo.isLFSFile
+
+	ctx.Data["IsLFSFile"] = fInfo.isLFSFile()
 	ctx.Data["FileSize"] = fInfo.fileSize
-	ctx.Data["IsTextFile"] = fInfo.isTextFile
-	ctx.Data["IsRepresentableAsText"] = isRepresentableAsText
-	ctx.Data["IsDisplayingSource"] = isDisplayingSource
-	ctx.Data["IsDisplayingRendered"] = isDisplayingRendered
+	ctx.Data["IsRepresentableAsText"] = fInfo.st.IsRepresentableAsText()
 	ctx.Data["IsExecutable"] = entry.IsExecutable()
+	ctx.Data["CanCopyContent"] = fInfo.st.IsRepresentableAsText() || fInfo.st.IsImage()
 
-	isTextSource := fInfo.isTextFile || isDisplayingSource
-	ctx.Data["IsTextSource"] = isTextSource
-	if isTextSource {
-		ctx.Data["CanCopyContent"] = true
-	}
-
-	// Check LFS Lock
-	lfsLock, err := git_model.GetTreePathLock(ctx, ctx.Repo.Repository.ID, ctx.Repo.TreePath)
-	ctx.Data["LFSLock"] = lfsLock
-	if err != nil {
-		ctx.ServerError("GetTreePathLock", err)
+	attrs, ok := prepareFileViewLfsAttrs(ctx)
+	if !ok {
 		return
 	}
-	if lfsLock != nil {
-		u, err := user_model.GetUserByID(ctx, lfsLock.OwnerID)
-		if err != nil {
-			ctx.ServerError("GetTreePathLock", err)
-			return
-		}
-		ctx.Data["LFSLockOwner"] = u.Name
-		ctx.Data["LFSLockOwnerHomeLink"] = u.HomeLink()
-		ctx.Data["LFSLockHint"] = ctx.Tr("repo.editor.this_file_locked")
-	}
 
-	// read all needed attributes which will be used later
-	// there should be no performance different between reading 2 or 4 here
-	attrsMap, err := attribute.CheckAttributes(ctx, ctx.Repo.GitRepo, ctx.Repo.CommitID, attribute.CheckAttributeOpts{
-		Filenames:  []string{ctx.Repo.TreePath},
-		Attributes: []string{attribute.LinguistGenerated, attribute.LinguistVendored, attribute.LinguistLanguage, attribute.GitlabLanguage},
-	})
-	if err != nil {
-		ctx.ServerError("attribute.CheckAttributes", err)
-		return
-	}
-	attrs := attrsMap[ctx.Repo.TreePath]
-	if attrs == nil {
-		// this case shouldn't happen, just in case.
-		setting.PanicInDevOrTesting("no attributes found for %s", ctx.Repo.TreePath)
-		attrs = attribute.NewAttributes()
-	}
+	// TODO: in the future maybe we need more accurate flags, for example:
+	// * IsRepresentableAsText: some files are text, some are not
+	// * IsRenderableXxx: some files are rendered by backend "markup" engine, some are rendered by frontend (pdf, 3d)
+	// * DefaultViewMode: when there is no "display" query parameter, which view mode should be used by default, source or rendered
 
+	utf8Reader := charset.ToUTF8WithFallbackReader(io.MultiReader(bytes.NewReader(buf), dataRc), charset.ConvertOpts{})
 	switch {
-	case isRepresentableAsText:
-		if fInfo.fileSize >= setting.UI.MaxDisplayFileSize {
-			ctx.Data["IsFileTooLarge"] = true
-			break
-		}
-
-		if fInfo.st.IsSvgImage() {
-			ctx.Data["IsImageFile"] = true
-			ctx.Data["CanCopyContent"] = true
-			ctx.Data["HasSourceRenderedToggle"] = true
-		}
-
-		rd := charset.ToUTF8WithFallbackReader(io.MultiReader(bytes.NewReader(buf), dataRc), charset.ConvertOpts{})
-
-		shouldRenderSource := ctx.FormString("display") == "source"
-		readmeExist := util.IsReadmeFileName(blob.Name())
-		ctx.Data["ReadmeExist"] = readmeExist
-
-		markupType := markup.DetectMarkupTypeByFileName(blob.Name())
-		if markupType == "" {
-			markupType = markup.DetectRendererType(blob.Name(), bytes.NewReader(buf))
-		}
-		if markupType != "" {
-			ctx.Data["HasSourceRenderedToggle"] = true
-		}
-		if markupType != "" && !shouldRenderSource {
-			ctx.Data["IsMarkup"] = true
-			ctx.Data["MarkupType"] = markupType
-			metas := ctx.Repo.Repository.ComposeRepoFileMetas(ctx)
-			metas["RefTypeNameSubURL"] = ctx.Repo.RefTypeNameSubURL()
-			rctx := renderhelper.NewRenderContextRepoFile(ctx, ctx.Repo.Repository, renderhelper.RepoFileOptions{
-				CurrentRefPath:  ctx.Repo.RefTypeNameSubURL(),
-				CurrentTreePath: path.Dir(ctx.Repo.TreePath),
-			}).
-				WithMarkupType(markupType).
-				WithRelativePath(ctx.Repo.TreePath).
-				WithMetas(metas)
-
-			ctx.Data["EscapeStatus"], ctx.Data["FileContent"], err = markupRender(ctx, rctx, rd)
-			if err != nil {
-				ctx.ServerError("Render", err)
-				return
-			}
-			// to prevent iframe load third-party url
-			ctx.Resp.Header().Add("Content-Security-Policy", "frame-src 'self'")
-		} else {
-			buf, _ := io.ReadAll(rd)
-
-			// The Open Group Base Specification: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html
-			//   empty: 0 lines; "a": 1 incomplete-line; "a\n": 1 line; "a\nb": 1 line, 1 incomplete-line;
-			// Gitea uses the definition (like most modern editors):
-			//   empty: 0 lines; "a": 1 line; "a\n": 2 lines; "a\nb": 2 lines;
-			//   When rendering, the last empty line is not rendered in UI, while the line-number is still counted, to tell users that the file contains a trailing EOL.
-			//   To make the UI more consistent, it could use an icon mark to indicate that there is no trailing EOL, and show line-number as the rendered lines.
-			// This NumLines is only used for the display on the UI: "xxx lines"
-			if len(buf) == 0 {
-				ctx.Data["NumLines"] = 0
-			} else {
-				ctx.Data["NumLines"] = bytes.Count(buf, []byte{'\n'}) + 1
-			}
-
-			language := attrs.GetLanguage().Value()
-			fileContent, lexerName, err := highlight.File(blob.Name(), language, buf)
-			ctx.Data["LexerName"] = lexerName
-			if err != nil {
-				log.Error("highlight.File failed, fallback to plain text: %v", err)
-				fileContent = highlight.PlainText(buf)
-			}
-			status := &charset.EscapeStatus{}
-			statuses := make([]*charset.EscapeStatus, len(fileContent))
-			for i, line := range fileContent {
-				statuses[i], fileContent[i] = charset.EscapeControlHTML(line, ctx.Locale)
-				status = status.Or(statuses[i])
-			}
-			ctx.Data["EscapeStatus"] = status
-			ctx.Data["FileContent"] = fileContent
-			ctx.Data["LineEscapeStatus"] = statuses
-		}
-
-	case fInfo.st.IsPDF():
-		ctx.Data["IsPDFFile"] = true
+	case fInfo.fileSize >= setting.UI.MaxDisplayFileSize:
+		ctx.Data["IsFileTooLarge"] = true
+	case handleFileViewRenderMarkup(ctx, entry.Name(), fInfo.st, buf, utf8Reader):
+		// it also sets ctx.Data["FileContent"] and more
+		ctx.Data["IsMarkup"] = true
+	case handleFileViewRenderSource(ctx, entry.Name(), attrs, fInfo, utf8Reader):
+		// it also sets ctx.Data["FileContent"] and more
+		ctx.Data["IsDisplayingSource"] = true
+	case handleFileViewRenderImage(ctx, fInfo, buf):
+		ctx.Data["IsImageFile"] = true
 	case fInfo.st.IsVideo():
 		ctx.Data["IsVideoFile"] = true
 	case fInfo.st.IsAudio():
 		ctx.Data["IsAudioFile"] = true
-	case fInfo.st.IsImage() && (setting.UI.SVG.Enabled || !fInfo.st.IsSvgImage()):
-		ctx.Data["IsImageFile"] = true
-		ctx.Data["CanCopyContent"] = true
 	default:
-		if fInfo.fileSize >= setting.UI.MaxDisplayFileSize {
-			ctx.Data["IsFileTooLarge"] = true
-			break
-		}
-
-		// TODO: this logic duplicates with "isRepresentableAsText=true", it is not the same as "LFSFileGet" in "lfs.go"
-		// It is used by "external renders", markupRender will execute external programs to get rendered content.
-		if markupType := markup.DetectMarkupTypeByFileName(blob.Name()); markupType != "" {
-			rd := io.MultiReader(bytes.NewReader(buf), dataRc)
-			ctx.Data["IsMarkup"] = true
-			ctx.Data["MarkupType"] = markupType
-
-			rctx := renderhelper.NewRenderContextRepoFile(ctx, ctx.Repo.Repository, renderhelper.RepoFileOptions{
-				CurrentRefPath:  ctx.Repo.RefTypeNameSubURL(),
-				CurrentTreePath: path.Dir(ctx.Repo.TreePath),
-			}).
-				WithMarkupType(markupType).
-				WithRelativePath(ctx.Repo.TreePath)
-
-			ctx.Data["EscapeStatus"], ctx.Data["FileContent"], err = markupRender(ctx, rctx, rd)
-			if err != nil {
-				ctx.ServerError("Render", err)
-				return
-			}
-		}
+		// unable to render anything, show the "view raw" or let frontend handle it
 	}
-
-	ctx.Data["IsVendored"], ctx.Data["IsGenerated"] = attrs.GetVendored().Value(), attrs.GetGenerated().Value()
-
-	if fInfo.st.IsImage() && !fInfo.st.IsSvgImage() {
-		img, _, err := image.DecodeConfig(bytes.NewReader(buf))
-		if err == nil {
-			// There are Image formats go can't decode
-			// Instead of throwing an error in that case, we show the size only when we can decode
-			ctx.Data["ImageSize"] = fmt.Sprintf("%dx%dpx", img.Width, img.Height)
-		}
-	}
-
-	prepareToRenderButtons(ctx, lfsLock)
 }
 
-func prepareToRenderButtons(ctx *context.Context, lfsLock *git_model.LFSLock) {
+func prepareFileViewEditorButtons(ctx *context.Context) bool {
 	// archived or mirror repository, the buttons should not be shown
 	if !ctx.Repo.Repository.CanEnableEditor() {
-		return
+		return true
 	}
 
 	// The buttons should not be shown if it's not a branch
 	if !ctx.Repo.RefFullName.IsBranch() {
 		ctx.Data["EditFileTooltip"] = ctx.Tr("repo.editor.must_be_on_a_branch")
 		ctx.Data["DeleteFileTooltip"] = ctx.Tr("repo.editor.must_be_on_a_branch")
-		return
+		return true
 	}
 
 	if !ctx.Repo.CanWriteToBranch(ctx, ctx.Doer, ctx.Repo.BranchName) {
@@ -306,7 +280,24 @@ func prepareToRenderButtons(ctx *context.Context, lfsLock *git_model.LFSLock) {
 		ctx.Data["EditFileTooltip"] = ctx.Tr("repo.editor.fork_before_edit")
 		ctx.Data["CanDeleteFile"] = true
 		ctx.Data["DeleteFileTooltip"] = ctx.Tr("repo.editor.must_have_write_access")
-		return
+		return true
+	}
+
+	lfsLock, err := git_model.GetTreePathLock(ctx, ctx.Repo.Repository.ID, ctx.Repo.TreePath)
+	ctx.Data["LFSLock"] = lfsLock
+	if err != nil {
+		ctx.ServerError("GetTreePathLock", err)
+		return false
+	}
+	if lfsLock != nil {
+		u, err := user_model.GetUserByID(ctx, lfsLock.OwnerID)
+		if err != nil {
+			ctx.ServerError("GetTreePathLock", err)
+			return false
+		}
+		ctx.Data["LFSLockOwner"] = u.Name
+		ctx.Data["LFSLockOwnerHomeLink"] = u.HomeLink()
+		ctx.Data["LFSLockHint"] = ctx.Tr("repo.editor.this_file_locked")
 	}
 
 	// it's a lfs file and the user is not the owner of the lock
@@ -315,4 +306,5 @@ func prepareToRenderButtons(ctx *context.Context, lfsLock *git_model.LFSLock) {
 	ctx.Data["EditFileTooltip"] = util.Iif(isLFSLocked, ctx.Tr("repo.editor.this_file_locked"), ctx.Tr("repo.editor.edit_this_file"))
 	ctx.Data["CanDeleteFile"] = !isLFSLocked
 	ctx.Data["DeleteFileTooltip"] = util.Iif(isLFSLocked, ctx.Tr("repo.editor.this_file_locked"), ctx.Tr("repo.editor.delete_this_file"))
+	return true
 }

routers/web/repo/view_home.go

@@ -339,7 +339,7 @@ func prepareToRenderDirOrFile(entry *git.TreeEntry) func(ctx *context.Context) {
 		if entry.IsDir() {
 			prepareToRenderDirectory(ctx)
 		} else {
-			prepareToRenderFile(ctx, entry)
+			prepareFileView(ctx, entry)
 		}
 	}
 }

routers/web/repo/view_readme.go

@@ -161,24 +161,23 @@ func prepareToRenderReadmeFile(ctx *context.Context, subfolder string, readmeFil
 	}
 	defer dataRc.Close()
 
-	ctx.Data["FileIsText"] = fInfo.isTextFile
+	ctx.Data["FileIsText"] = fInfo.st.IsText()
 	ctx.Data["FileTreePath"] = path.Join(ctx.Repo.TreePath, subfolder, readmeFile.Name())
 	ctx.Data["FileSize"] = fInfo.fileSize
-	ctx.Data["IsLFSFile"] = fInfo.isLFSFile
+	ctx.Data["IsLFSFile"] = fInfo.isLFSFile()
 
-	if fInfo.isLFSFile {
+	if fInfo.isLFSFile() {
 		filenameBase64 := base64.RawURLEncoding.EncodeToString([]byte(readmeFile.Name()))
 		ctx.Data["RawFileLink"] = fmt.Sprintf("%s.git/info/lfs/objects/%s/%s", ctx.Repo.Repository.Link(), url.PathEscape(fInfo.lfsMeta.Oid), url.PathEscape(filenameBase64))
 	}
 
-	if !fInfo.isTextFile {
+	if !fInfo.st.IsText() {
 		return
 	}
 
 	if fInfo.fileSize >= setting.UI.MaxDisplayFileSize {
 		// Pretend that this is a normal text file to display 'This file is too large to be shown'
 		ctx.Data["IsFileTooLarge"] = true
-		ctx.Data["IsTextFile"] = true
 		return
 	}
 
@@ -212,7 +211,7 @@ func prepareToRenderReadmeFile(ctx *context.Context, subfolder string, readmeFil
 		ctx.Data["EscapeStatus"], ctx.Data["FileContent"] = charset.EscapeControlHTML(template.HTML(contentEscaped), ctx.Locale)
 	}
 
-	if !fInfo.isLFSFile && ctx.Repo.Repository.CanEnableEditor() {
+	if !fInfo.isLFSFile() && ctx.Repo.Repository.CanEnableEditor() {
 		ctx.Data["CanEditReadmeFile"] = true
 	}
 }

templates/repo/blame.tmpl

@@ -82,6 +82,8 @@
 			</table>
 			{{end}}{{/* end if .IsFileTooLarge */}}
 			<div class="code-line-menu tippy-target">
+				{{/*FIXME: the "HasSourceRenderedToggle" is never set on blame page, it should mean "whether the file is renderable".
+				If the file is renderable, then it must has the "display=source" parameter to make sure the file view page shows the source code, then line number works. */}}
 				{{if $.Permission.CanRead ctx.Consts.RepoUnitTypeIssues}}
 					<a class="item ref-in-new-issue" role="menuitem" data-url-issue-new="{{.RepoLink}}/issues/new" data-url-param-body-link="{{.Repository.Link}}/src/commit/{{PathEscape .CommitID}}/{{PathEscapeSegments .TreePath}}{{if $.HasSourceRenderedToggle}}?display=source{{end}}" rel="nofollow noindex">{{ctx.Locale.Tr "repo.issues.context.reference_issue"}}</a>
 				{{end}}

templates/repo/editor/common_breadcrumb.tmpl

@@ -5,7 +5,7 @@
 	{{range $i, $v := .TreeNames}}
 		<div class="breadcrumb-divider">/</div>
 		{{if eq $i $l}}
-			<input id="file-name" maxlength="255" value="{{$v}}" placeholder="{{ctx.Locale.Tr (Iif $.PageIsUpload "repo.editor.add_subdir" "repo.editor.name_your_file")}}" data-editorconfig="{{$.EditorconfigJson}}" required autofocus>
+			<input id="file-name" maxlength="255" value="{{$v}}" placeholder="{{ctx.Locale.Tr (Iif $.PageIsUpload "repo.editor.add_subdir" "repo.editor.name_your_file")}}" data-editorconfig="{{$.EditorconfigJson}}" {{Iif $.PageIsUpload "" "required"}} autofocus>
 			<span data-tooltip-content="{{ctx.Locale.Tr "repo.editor.filename_help"}}">{{svg "octicon-info"}}</span>
 		{{else}}
 			<span class="section"><a href="{{$.BranchLink}}/{{index $.TreePaths $i | PathEscapeSegments}}">{{$v}}</a></span>

templates/repo/settings/lfs_file.tmpl

@@ -30,8 +30,6 @@
 								<audio controls src="{{$.RawFileLink}}">
 									<strong>{{ctx.Locale.Tr "repo.audio_not_supported_in_browser"}}</strong>
 								</audio>
-							{{else if .IsPDFFile}}
-								<div class="pdf-content is-loading" data-global-init="initPdfViewer" data-src="{{$.RawFileLink}}" data-fallback-button-text="{{ctx.Locale.Tr "diff.view_file"}}"></div>
 							{{else}}
 								<a href="{{$.RawFileLink}}" rel="nofollow" class="tw-p-4">{{ctx.Locale.Tr "repo.file_view_raw"}}</a>
 							{{end}}

templates/repo/view_file.tmpl

@@ -1,4 +1,6 @@
-<div {{if .ReadmeInList}}id="readme" {{end}}class="{{TabSizeClass .Editorconfig .FileTreePath}} non-diff-file-content">
+<div {{if .ReadmeInList}}id="readme"{{end}} class="{{TabSizeClass .Editorconfig .FileTreePath}} non-diff-file-content"
+	data-global-init="initRepoFileView" data-raw-file-link="{{.RawFileLink}}">
+
 	{{- if .FileError}}
 		<div class="ui error message">
 			<div class="text left tw-whitespace-pre">{{.FileError}}</div>
@@ -32,13 +34,14 @@
 				{{template "repo/file_info" .}}
 			{{end}}
 		</div>
-		<div class="file-header-right file-actions tw-flex tw-items-center tw-flex-wrap">
-			{{if .HasSourceRenderedToggle}}
-				<div class="ui compact icon buttons">
-					<a href="?display=source" class="ui mini basic button {{if .IsDisplayingSource}}active{{end}}" data-tooltip-content="{{ctx.Locale.Tr "repo.file_view_source"}}">{{svg "octicon-code" 15}}</a>
-					<a href="{{$.Link}}" class="ui mini basic button {{if .IsDisplayingRendered}}active{{end}}" data-tooltip-content="{{ctx.Locale.Tr "repo.file_view_rendered"}}">{{svg "octicon-file" 15}}</a>
-				</div>
-			{{end}}
+		<div class="file-header-right file-actions flex-text-block tw-flex-wrap">
+			{{/* this componment is also controlled by frontend plugin renders */}}
+			<div class="ui compact icon buttons file-view-toggle-buttons {{Iif .HasSourceRenderedToggle "" "tw-hidden"}}">
+				{{if .IsRepresentableAsText}}
+				<a href="?display=source" class="ui mini basic button file-view-toggle-source {{if .IsDisplayingSource}}active{{end}}" data-tooltip-content="{{ctx.Locale.Tr "repo.file_view_source"}}">{{svg "octicon-code" 15}}</a>
+				{{end}}
+				<a href="?display=rendered" class="ui mini basic button file-view-toggle-rendered {{if not .IsDisplayingSource}}active{{end}}" data-tooltip-content="{{ctx.Locale.Tr "repo.file_view_rendered"}}">{{svg "octicon-file" 15}}</a>
+			</div>
 			{{if not .ReadmeInList}}
 				<div class="ui buttons tw-mr-1">
 					<a class="ui mini basic button" href="{{$.RawFileLink}}">{{ctx.Locale.Tr "repo.file_raw"}}</a>
@@ -55,7 +58,10 @@
 					{{end}}
 				</div>
 				<a download class="btn-octicon" data-tooltip-content="{{ctx.Locale.Tr "repo.download_file"}}" href="{{$.RawFileLink}}">{{svg "octicon-download"}}</a>
-				<a class="btn-octicon {{if not .CanCopyContent}} disabled{{end}}" data-global-click="onCopyContentButtonClick" {{if or .IsImageFile (and .HasSourceRenderedToggle (not .IsDisplayingSource))}} data-link="{{$.RawFileLink}}"{{end}} data-tooltip-content="{{if .CanCopyContent}}{{ctx.Locale.Tr "copy_content"}}{{else}}{{ctx.Locale.Tr "copy_type_unsupported"}}{{end}}">{{svg "octicon-copy"}}</a>
+				<a class="btn-octicon {{if not .CanCopyContent}}disabled{{end}}" data-global-click="onCopyContentButtonClick"
+					{{if not .IsDisplayingSource}}data-raw-file-link="{{$.RawFileLink}}"{{end}}
+					data-tooltip-content="{{if .CanCopyContent}}{{ctx.Locale.Tr "copy_content"}}{{else}}{{ctx.Locale.Tr "copy_type_unsupported"}}{{end}}"
+				>{{svg "octicon-copy"}}</a>
 				{{if .EnableFeed}}
 				<a class="btn-octicon" href="{{$.RepoLink}}/rss/{{$.RefTypeNameSubURL}}/{{PathEscapeSegments .TreePath}}" data-tooltip-content="{{ctx.Locale.Tr "rss_feed"}}">
 					{{svg "octicon-rss"}}
@@ -82,20 +88,36 @@
 			{{end}}
 		</div>
 	</h4>
+
 	<div class="ui bottom attached table unstackable segment">
-		{{if not (or .IsMarkup .IsRenderedHTML)}}
-			{{template "repo/unicode_escape_prompt" dict "EscapeStatus" .EscapeStatus "root" $}}
+		{{if not .IsMarkup}}
+			{{template "repo/unicode_escape_prompt" dict "EscapeStatus" .EscapeStatus}}
 		{{end}}
-		<div class="file-view{{if .IsMarkup}} markup {{.MarkupType}}{{else if .IsPlainText}} plain-text{{else if .IsTextSource}} code-view{{end}}">
+		<div class="file-view {{if .IsMarkup}}markup {{.MarkupType}}{{else if .IsPlainText}}plain-text{{else if .IsDisplayingSource}}code-view{{end}}">
 			{{if .IsFileTooLarge}}
 				{{template "shared/filetoolarge" dict "RawFileLink" .RawFileLink}}
 			{{else if not .FileSize}}
 				{{template "shared/fileisempty"}}
 			{{else if .IsMarkup}}
-				{{if .FileContent}}{{.FileContent}}{{end}}
+				{{.FileContent}}
 			{{else if .IsPlainText}}
 				<pre>{{if .FileContent}}{{.FileContent}}{{end}}</pre>
-			{{else if not .IsTextSource}}
+			{{else if .FileContent}}
+				<table>
+					<tbody>
+					{{range $idx, $code := .FileContent}}
+						{{$line := Eval $idx "+" 1}}
+						<tr>
+							<td id="L{{$line}}" class="lines-num"><span id="L{{$line}}" data-line-number="{{$line}}"></span></td>
+							{{if $.EscapeStatus.Escaped}}
+								<td class="lines-escape">{{if (index $.LineEscapeStatus $idx).Escaped}}<button class="toggle-escape-button btn interact-bg" title="{{if (index $.LineEscapeStatus $idx).HasInvisible}}{{ctx.Locale.Tr "repo.invisible_runes_line"}} {{end}}{{if (index $.LineEscapeStatus $idx).HasAmbiguous}}{{ctx.Locale.Tr "repo.ambiguous_runes_line"}}{{end}}"></button>{{end}}</td>
+							{{end}}
+							<td rel="L{{$line}}" class="lines-code chroma"><code class="code-inner">{{$code}}</code></td>
+						</tr>
+					{{end}}
+					</tbody>
+				</table>
+			{{else}}
 				<div class="view-raw">
 					{{if .IsImageFile}}
 						<img alt="{{$.RawFileLink}}" src="{{$.RawFileLink}}">
@@ -107,35 +129,23 @@
 						<audio controls src="{{$.RawFileLink}}">
 							<strong>{{ctx.Locale.Tr "repo.audio_not_supported_in_browser"}}</strong>
 						</audio>
-					{{else if .IsPDFFile}}
-						<div class="pdf-content is-loading" data-global-init="initPdfViewer" data-src="{{$.RawFileLink}}" data-fallback-button-text="{{ctx.Locale.Tr "repo.diff.view_file"}}"></div>
 					{{else}}
-						<a href="{{$.RawFileLink}}" rel="nofollow" class="tw-p-4">{{ctx.Locale.Tr "repo.file_view_raw"}}</a>
+						<div class="file-view-render-container">
+							<div class="file-view-raw-prompt tw-p-4">
+								<a href="{{$.RawFileLink}}" rel="nofollow">{{ctx.Locale.Tr "repo.file_view_raw"}}</a>
+							</div>
+						</div>
 					{{end}}
 				</div>
-			{{else if .FileSize}}
-				<table>
-					<tbody>
-						{{range $idx, $code := .FileContent}}
-						{{$line := Eval $idx "+" 1}}
-						<tr>
-							<td id="L{{$line}}" class="lines-num"><span id="L{{$line}}" data-line-number="{{$line}}"></span></td>
-							{{if $.EscapeStatus.Escaped}}
-								<td class="lines-escape">{{if (index $.LineEscapeStatus $idx).Escaped}}<button class="toggle-escape-button btn interact-bg" title="{{if (index $.LineEscapeStatus $idx).HasInvisible}}{{ctx.Locale.Tr "repo.invisible_runes_line"}} {{end}}{{if (index $.LineEscapeStatus $idx).HasAmbiguous}}{{ctx.Locale.Tr "repo.ambiguous_runes_line"}}{{end}}"></button>{{end}}</td>
-							{{end}}
-							<td rel="L{{$line}}" class="lines-code chroma"><code class="code-inner">{{$code}}</code></td>
-						</tr>
-						{{end}}
-					</tbody>
-				</table>
-				<div class="code-line-menu tippy-target">
-					{{if $.Permission.CanRead ctx.Consts.RepoUnitTypeIssues}}
-						<a class="item ref-in-new-issue" role="menuitem" data-url-issue-new="{{.RepoLink}}/issues/new" data-url-param-body-link="{{.Repository.Link}}/src/commit/{{PathEscape .CommitID}}/{{PathEscapeSegments .TreePath}}{{if $.HasSourceRenderedToggle}}?display=source{{end}}" rel="nofollow noindex">{{ctx.Locale.Tr "repo.issues.context.reference_issue"}}</a>
-					{{end}}
-					<a class="item view_git_blame" role="menuitem" href="{{.Repository.Link}}/blame/commit/{{PathEscape .CommitID}}/{{PathEscapeSegments .TreePath}}">{{ctx.Locale.Tr "repo.view_git_blame"}}</a>
-					<a class="item copy-line-permalink" role="menuitem" data-url="{{.Repository.Link}}/src/commit/{{PathEscape .CommitID}}/{{PathEscapeSegments .TreePath}}{{if $.HasSourceRenderedToggle}}?display=source{{end}}">{{ctx.Locale.Tr "repo.file_copy_permalink"}}</a>
-				</div>
 			{{end}}
 		</div>
+
+		<div class="code-line-menu tippy-target">
+			{{if $.Permission.CanRead ctx.Consts.RepoUnitTypeIssues}}
+			<a class="item ref-in-new-issue" role="menuitem" data-url-issue-new="{{.RepoLink}}/issues/new" data-url-param-body-link="{{.Repository.Link}}/src/commit/{{PathEscape .CommitID}}/{{PathEscapeSegments .TreePath}}{{if $.HasSourceRenderedToggle}}?display=source{{end}}" rel="nofollow noindex">{{ctx.Locale.Tr "repo.issues.context.reference_issue"}}</a>
+			{{end}}
+			<a class="item view_git_blame" role="menuitem" href="{{.Repository.Link}}/blame/commit/{{PathEscape .CommitID}}/{{PathEscapeSegments .TreePath}}">{{ctx.Locale.Tr "repo.view_git_blame"}}</a>
+			<a class="item copy-line-permalink" role="menuitem" data-url="{{.Repository.Link}}/src/commit/{{PathEscape .CommitID}}/{{PathEscapeSegments .TreePath}}{{if $.HasSourceRenderedToggle}}?display=source{{end}}">{{ctx.Locale.Tr "repo.file_copy_permalink"}}</a>
+		</div>
 	</div>
 </div>

tests/integration/lfs_view_test.go

@@ -68,14 +68,15 @@ func TestLFSRender(t *testing.T) {
 		req := NewRequest(t, "GET", "/user2/lfs/src/branch/master/crypt.bin")
 		resp := session.MakeRequest(t, req, http.StatusOK)
 
-		doc := NewHTMLParser(t, resp.Body).doc
+		doc := NewHTMLParser(t, resp.Body)
 
 		fileInfo := doc.Find("div.file-info-entry").First().Text()
 		assert.Contains(t, fileInfo, "LFS")
 
-		rawLink, exists := doc.Find("div.file-view > div.view-raw > a").Attr("href")
-		assert.True(t, exists, "Download link should render instead of content because this is a binary file")
-		assert.Equal(t, "/user2/lfs/media/branch/master/crypt.bin", rawLink, "The download link should use the proper /media link because it's in LFS")
+		// find new file view container
+		fileViewContainer := doc.Find("[data-global-init=initRepoFileView]")
+		assert.Equal(t, "/user2/lfs/media/branch/master/crypt.bin", fileViewContainer.AttrOr("data-raw-file-link", ""))
+		AssertHTMLElement(t, doc, ".view-raw > .file-view-render-container > .file-view-raw-prompt", 1)
 	})
 
 	// check that a directory with a README file shows its text

web_src/css/modules/animations.css

@@ -52,8 +52,7 @@ form.single-button-form.is-loading .button {
 }
 
 .markup pre.is-loading,
-.editor-loading.is-loading,
-.pdf-content.is-loading {
+.editor-loading.is-loading {
   height: var(--height-loading);
 }
 

web_src/css/repo.css

@@ -183,42 +183,6 @@ td .commit-summary {
   cursor: default;
 }
 
-.view-raw {
-  display: flex;
-  justify-content: center;
-  align-items: center;
-}
-
-.view-raw > * {
-  max-width: 100%;
-}
-
-.view-raw audio,
-.view-raw video,
-.view-raw img {
-  margin: 1rem 0;
-  border-radius: 0;
-  object-fit: contain;
-}
-
-.view-raw img[src$=".svg" i] {
-  max-height: 600px !important;
-  max-width: 600px !important;
-}
-
-.pdf-content {
-  width: 100%;
-  height: 600px;
-  border: none !important;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-}
-
-.pdf-content .pdf-fallback-button {
-  margin: 50px auto;
-}
-
 .repository.file.list .non-diff-file-content .plain-text {
   padding: 1em 2em;
 }
@@ -241,10 +205,6 @@ td .commit-summary {
   padding: 0 !important;
 }
 
-.non-diff-file-content .pdfobject {
-  border-radius: 0 0 var(--border-radius) var(--border-radius);
-}
-
 .repo-editor-header {
   width: 100%;
 }

web_src/css/repo/file-view.css

@@ -60,3 +60,33 @@
 .file-view.code-view .ui.button.code-line-button:hover {
   background: var(--color-secondary);
 }
+
+.view-raw {
+  display: flex;
+  justify-content: center;
+}
+
+.view-raw > * {
+  max-width: 100%;
+}
+
+.view-raw audio,
+.view-raw video,
+.view-raw img {
+  margin: 1rem;
+  border-radius: 0;
+  object-fit: contain;
+}
+
+.view-raw img[src$=".svg" i] {
+  max-height: 600px !important;
+  max-width: 600px !important;
+}
+
+.file-view-render-container {
+  width: 100%;
+}
+
+.file-view-render-container :last-child {
+  border-radius: 0 0 var(--border-radius) var(--border-radius); /* to match the "ui segment" bottom radius */
+}

web_src/js/features/copycontent.ts

@@ -9,17 +9,17 @@ const {i18n} = window.config;
 export function initCopyContent() {
   registerGlobalEventFunc('click', 'onCopyContentButtonClick', async (btn: HTMLElement) => {
     if (btn.classList.contains('disabled') || btn.classList.contains('is-loading')) return;
-    let content;
-    let isRasterImage = false;
-    const link = btn.getAttribute('data-link');
+    const rawFileLink = btn.getAttribute('data-raw-file-link');
 
-    // when data-link is present, we perform a fetch. this is either because
-    // the text to copy is not in the DOM, or it is an image which should be
+    let content, isRasterImage = false;
+
+    // when "data-raw-link" is present, we perform a fetch. this is either because
+    // the text to copy is not in the DOM, or it is an image that should be
     // fetched to copy in full resolution
-    if (link) {
+    if (rawFileLink) {
       btn.classList.add('is-loading', 'loading-icon-2px');
       try {
-        const res = await GET(link, {credentials: 'include', redirect: 'follow'});
+        const res = await GET(rawFileLink, {credentials: 'include', redirect: 'follow'});
         const contentType = res.headers.get('content-type');
 
         if (contentType.startsWith('image/') && !contentType.startsWith('image/svg')) {

web_src/js/features/file-view.ts

@@ -0,0 +1,76 @@
+import type {FileRenderPlugin} from '../render/plugin.ts';
+import {newRenderPlugin3DViewer} from '../render/plugins/3d-viewer.ts';
+import {newRenderPluginPdfViewer} from '../render/plugins/pdf-viewer.ts';
+import {registerGlobalInitFunc} from '../modules/observer.ts';
+import {createElementFromHTML, showElem, toggleClass} from '../utils/dom.ts';
+import {htmlEscape} from 'escape-goat';
+import {basename} from '../utils.ts';
+
+const plugins: FileRenderPlugin[] = [];
+
+function initPluginsOnce(): void {
+  if (plugins.length) return;
+  plugins.push(newRenderPlugin3DViewer(), newRenderPluginPdfViewer());
+}
+
+function findFileRenderPlugin(filename: string, mimeType: string): FileRenderPlugin | null {
+  return plugins.find((plugin) => plugin.canHandle(filename, mimeType)) || null;
+}
+
+function showRenderRawFileButton(elFileView: HTMLElement, renderContainer: HTMLElement | null): void {
+  const toggleButtons = elFileView.querySelector('.file-view-toggle-buttons');
+  showElem(toggleButtons);
+  const displayingRendered = Boolean(renderContainer);
+  toggleClass(toggleButtons.querySelectorAll('.file-view-toggle-source'), 'active', !displayingRendered); // it may not exist
+  toggleClass(toggleButtons.querySelector('.file-view-toggle-rendered'), 'active', displayingRendered);
+  // TODO: if there is only one button, hide it?
+}
+
+async function renderRawFileToContainer(container: HTMLElement, rawFileLink: string, mimeType: string) {
+  const elViewRawPrompt = container.querySelector('.file-view-raw-prompt');
+  if (!rawFileLink || !elViewRawPrompt) throw new Error('unexpected file view container');
+
+  let rendered = false, errorMsg = '';
+  try {
+    const plugin = findFileRenderPlugin(basename(rawFileLink), mimeType);
+    if (plugin) {
+      container.classList.add('is-loading');
+      container.setAttribute('data-render-name', plugin.name); // not used yet
+      await plugin.render(container, rawFileLink);
+      rendered = true;
+    }
+  } catch (e) {
+    errorMsg = `${e}`;
+  } finally {
+    container.classList.remove('is-loading');
+  }
+
+  if (rendered) {
+    elViewRawPrompt.remove();
+    return;
+  }
+
+  // remove all children from the container, and only show the raw file link
+  container.replaceChildren(elViewRawPrompt);
+
+  if (errorMsg) {
+    const elErrorMessage = createElementFromHTML(htmlEscape`<div class="ui error message">${errorMsg}</div>`);
+    elViewRawPrompt.insertAdjacentElement('afterbegin', elErrorMessage);
+  }
+}
+
+export function initRepoFileView(): void {
+  registerGlobalInitFunc('initRepoFileView', async (elFileView: HTMLElement) => {
+    initPluginsOnce();
+    const rawFileLink = elFileView.getAttribute('data-raw-file-link');
+    const mimeType = elFileView.getAttribute('data-mime-type') || ''; // not used yet
+    // TODO: we should also provide the prefetched file head bytes to let the plugin decide whether to render or not
+    const plugin = findFileRenderPlugin(basename(rawFileLink), mimeType);
+    if (!plugin) return;
+
+    const renderContainer = elFileView.querySelector<HTMLElement>('.file-view-render-container');
+    showRenderRawFileButton(elFileView, renderContainer);
+    // maybe in the future multiple plugins can render the same file, so we should not assume only one plugin will render it
+    if (renderContainer) await renderRawFileToContainer(renderContainer, rawFileLink, mimeType);
+  });
+}

web_src/js/index.ts

@@ -19,7 +19,7 @@ import {initRepoIssueContentHistory} from './features/repo-issue-content.ts';
 import {initStopwatch} from './features/stopwatch.ts';
 import {initFindFileInRepo} from './features/repo-findfile.ts';
 import {initMarkupContent} from './markup/content.ts';
-import {initPdfViewer} from './render/pdf.ts';
+import {initRepoFileView} from './features/file-view.ts';
 import {initUserAuthOauth2, initUserCheckAppUrl} from './features/user-auth.ts';
 import {initRepoPullRequestAllowMaintainerEdit, initRepoPullRequestReview, initRepoIssueSidebarDependency, initRepoIssueFilterItemLabel} from './features/repo-issue.ts';
 import {initRepoEllipsisButton, initCommitStatuses} from './features/repo-commit.ts';
@@ -159,10 +159,11 @@ onDomReady(() => {
     initUserAuthWebAuthnRegister,
     initUserSettings,
     initRepoDiffView,
-    initPdfViewer,
     initColorPickers,
 
     initOAuth2SettingsDisableCheckbox,
+
+    initRepoFileView,
   ]);
 
   // it must be the last one, then the "querySelectorAll" only needs to be executed once for global init functions.

web_src/js/render/pdf.ts

@@ -1,17 +0,0 @@
-import {htmlEscape} from 'escape-goat';
-import {registerGlobalInitFunc} from '../modules/observer.ts';
-
-export async function initPdfViewer() {
-  registerGlobalInitFunc('initPdfViewer', async (el: HTMLInputElement) => {
-    const pdfobject = await import(/* webpackChunkName: "pdfobject" */'pdfobject');
-
-    const src = el.getAttribute('data-src');
-    const fallbackText = el.getAttribute('data-fallback-button-text');
-    pdfobject.embed(src, el, {
-      fallbackLink: htmlEscape`
-        <a role="button" class="ui basic button pdf-fallback-button" href="[url]">${fallbackText}</a>
-      `,
-    });
-    el.classList.remove('is-loading');
-  });
-}

web_src/js/render/plugin.ts

@@ -0,0 +1,10 @@
+export type FileRenderPlugin = {
+  // unique plugin name
+  name: string;
+
+  // test if plugin can handle a specified file
+  canHandle: (filename: string, mimeType: string) => boolean;
+
+  // render file content
+  render: (container: HTMLElement, fileUrl: string, options?: any) => Promise<void>;
+}

web_src/js/render/plugins/3d-viewer.ts

@@ -0,0 +1,60 @@
+import type {FileRenderPlugin} from '../plugin.ts';
+import {extname} from '../../utils.ts';
+
+// support common 3D model file formats, use online-3d-viewer library for rendering
+
+// eslint-disable-next-line multiline-comment-style
+/* a simple text STL file example:
+solid SimpleTriangle
+  facet normal 0 0 1
+    outer loop
+      vertex 0 0 0
+      vertex 1 0 0
+      vertex 0 1 0
+    endloop
+  endfacet
+endsolid SimpleTriangle
+*/
+
+export function newRenderPlugin3DViewer(): FileRenderPlugin {
+  // Some extensions are text-based formats:
+  // .3mf .amf .brep: XML
+  // .fbx: XML or BINARY
+  // .dae .gltf: JSON
+  // .ifc, .igs, .iges, .stp, .step are: TEXT
+  // .stl .ply: TEXT or BINARY
+  // .obj .off .wrl: TEXT
+  // So we need to be able to render when the file is recognized as plaintext file by backend.
+  //
+  // It needs more logic to make it overall right (render a text 3D model automatically):
+  // we need to distinguish the ambiguous filename extensions.
+  // For example: "*.obj, *.off, *.step" might be or not be a 3D model file.
+  // So when it is a text file, we can't assume that "we only render it by 3D plugin",
+  // otherwise the end users would be impossible to view its real content when the file is not a 3D model.
+  const SUPPORTED_EXTENSIONS = [
+    '.3dm', '.3ds', '.3mf', '.amf', '.bim', '.brep',
+    '.dae', '.fbx', '.fcstd', '.glb', '.gltf',
+    '.ifc', '.igs', '.iges', '.stp', '.step',
+    '.stl', '.obj', '.off', '.ply', '.wrl',
+  ];
+
+  return {
+    name: '3d-model-viewer',
+
+    canHandle(filename: string, _mimeType: string): boolean {
+      const ext = extname(filename).toLowerCase();
+      return SUPPORTED_EXTENSIONS.includes(ext);
+    },
+
+    async render(container: HTMLElement, fileUrl: string): Promise<void> {
+      // TODO: height and/or max-height?
+      const OV = await import(/* webpackChunkName: "online-3d-viewer" */'online-3d-viewer');
+      const viewer = new OV.EmbeddedViewer(container, {
+        backgroundColor: new OV.RGBAColor(59, 68, 76, 0),
+        defaultColor: new OV.RGBColor(65, 131, 196),
+        edgeSettings: new OV.EdgeSettings(false, new OV.RGBColor(0, 0, 0), 1),
+      });
+      viewer.LoadModelFromUrlList([fileUrl]);
+    },
+  };
+}

web_src/js/render/plugins/pdf-viewer.ts

@@ -0,0 +1,20 @@
+import type {FileRenderPlugin} from '../plugin.ts';
+
+export function newRenderPluginPdfViewer(): FileRenderPlugin {
+  return {
+    name: 'pdf-viewer',
+
+    canHandle(filename: string, _mimeType: string): boolean {
+      return filename.toLowerCase().endsWith('.pdf');
+    },
+
+    async render(container: HTMLElement, fileUrl: string): Promise<void> {
+      const PDFObject = await import(/* webpackChunkName: "pdfobject" */'pdfobject');
+      // TODO: the PDFObject library does not support dynamic height adjustment,
+      container.style.height = `${window.innerHeight - 100}px`;
+      if (!PDFObject.default.embed(fileUrl, container)) {
+        throw new Error('Unable to render the PDF file');
+      }
+    },
+  };
+}