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| 1 | +// Copyright 2023 The Gitea Authors. All rights reserved. |
| 2 | +// SPDX-License-Identifier: MIT |
| 3 | + |
| 4 | +package httplib |
| 5 | + |
| 6 | +import ( |
| 7 | + "bytes" |
| 8 | + "errors" |
| 9 | + "fmt" |
| 10 | + "io" |
| 11 | + "net/http" |
| 12 | + "net/url" |
| 13 | + "path" |
| 14 | + "path/filepath" |
| 15 | + "strconv" |
| 16 | + "strings" |
| 17 | + "time" |
| 18 | + |
| 19 | + charsetModule "code.gitea.io/gitea/modules/charset" |
| 20 | + "code.gitea.io/gitea/modules/httpcache" |
| 21 | + "code.gitea.io/gitea/modules/log" |
| 22 | + "code.gitea.io/gitea/modules/setting" |
| 23 | + "code.gitea.io/gitea/modules/typesniffer" |
| 24 | + "code.gitea.io/gitea/modules/util" |
| 25 | +) |
| 26 | + |
| 27 | +type ServeHeaderOptions struct { |
| 28 | + ContentType string // defaults to "application/octet-stream" |
| 29 | + ContentTypeCharset string |
| 30 | + ContentLength *int64 |
| 31 | + Disposition string // defaults to "attachment" |
| 32 | + Filename string |
| 33 | + CacheDuration time.Duration // defaults to 5 minutes |
| 34 | + LastModified time.Time |
| 35 | +} |
| 36 | + |
| 37 | +// ServeSetHeaders sets necessary content serve headers |
| 38 | +func ServeSetHeaders(w http.ResponseWriter, opts *ServeHeaderOptions) { |
| 39 | + header := w.Header() |
| 40 | + |
| 41 | + contentType := typesniffer.ApplicationOctetStream |
| 42 | + if opts.ContentType != "" { |
| 43 | + if opts.ContentTypeCharset != "" { |
| 44 | + contentType = opts.ContentType + "; charset=" + strings.ToLower(opts.ContentTypeCharset) |
| 45 | + } else { |
| 46 | + contentType = opts.ContentType |
| 47 | + } |
| 48 | + } |
| 49 | + header.Set("Content-Type", contentType) |
| 50 | + header.Set("X-Content-Type-Options", "nosniff") |
| 51 | + |
| 52 | + if opts.ContentLength != nil { |
| 53 | + header.Set("Content-Length", strconv.FormatInt(*opts.ContentLength, 10)) |
| 54 | + } |
| 55 | + |
| 56 | + if opts.Filename != "" { |
| 57 | + disposition := opts.Disposition |
| 58 | + if disposition == "" { |
| 59 | + disposition = "attachment" |
| 60 | + } |
| 61 | + |
| 62 | + backslashEscapedName := strings.ReplaceAll(strings.ReplaceAll(opts.Filename, `\`, `\\`), `"`, `\"`) // \ -> \\, " -> \" |
| 63 | + header.Set("Content-Disposition", fmt.Sprintf(`%s; filename="%s"; filename*=UTF-8''%s`, disposition, backslashEscapedName, url.PathEscape(opts.Filename))) |
| 64 | + header.Set("Access-Control-Expose-Headers", "Content-Disposition") |
| 65 | + } |
| 66 | + |
| 67 | + duration := opts.CacheDuration |
| 68 | + if duration == 0 { |
| 69 | + duration = 5 * time.Minute |
| 70 | + } |
| 71 | + httpcache.SetCacheControlInHeader(header, duration) |
| 72 | + |
| 73 | + if !opts.LastModified.IsZero() { |
| 74 | + header.Set("Last-Modified", opts.LastModified.UTC().Format(http.TimeFormat)) |
| 75 | + } |
| 76 | +} |
| 77 | + |
| 78 | +// ServeData download file from io.Reader |
| 79 | +func setServeHeadersByFile(r *http.Request, w http.ResponseWriter, filePath string, mineBuf []byte) { |
| 80 | + // do not set "Content-Length", because the length could only be set by callers, and it needs to support range requests |
| 81 | + opts := &ServeHeaderOptions{ |
| 82 | + Filename: path.Base(filePath), |
| 83 | + } |
| 84 | + |
| 85 | + sniffedType := typesniffer.DetectContentType(mineBuf) |
| 86 | + |
| 87 | + // the "render" parameter came from year 2016: 638dd24c, it doesn't have clear meaning, so I think it could be removed later |
| 88 | + isPlain := sniffedType.IsText() || r.FormValue("render") != "" |
| 89 | + |
| 90 | + if setting.MimeTypeMap.Enabled { |
| 91 | + fileExtension := strings.ToLower(filepath.Ext(filePath)) |
| 92 | + opts.ContentType = setting.MimeTypeMap.Map[fileExtension] |
| 93 | + } |
| 94 | + |
| 95 | + if opts.ContentType == "" { |
| 96 | + if sniffedType.IsBrowsableBinaryType() { |
| 97 | + opts.ContentType = sniffedType.GetMimeType() |
| 98 | + } else if isPlain { |
| 99 | + opts.ContentType = "text/plain" |
| 100 | + } else { |
| 101 | + opts.ContentType = typesniffer.ApplicationOctetStream |
| 102 | + } |
| 103 | + } |
| 104 | + |
| 105 | + if isPlain { |
| 106 | + charset, err := charsetModule.DetectEncoding(mineBuf) |
| 107 | + if err != nil { |
| 108 | + log.Error("Detect raw file %s charset failed: %v, using by default utf-8", filePath, err) |
| 109 | + charset = "utf-8" |
| 110 | + } |
| 111 | + opts.ContentTypeCharset = strings.ToLower(charset) |
| 112 | + } |
| 113 | + |
| 114 | + isSVG := sniffedType.IsSvgImage() |
| 115 | + |
| 116 | + // serve types that can present a security risk with CSP |
| 117 | + if isSVG { |
| 118 | + w.Header().Set("Content-Security-Policy", "default-src 'none'; style-src 'unsafe-inline'; sandbox") |
| 119 | + } else if sniffedType.IsPDF() { |
| 120 | + // no sandbox attribute for pdf as it breaks rendering in at least safari. this |
| 121 | + // should generally be safe as scripts inside PDF can not escape the PDF document |
| 122 | + // see https://bugs.chromium.org/p/chromium/issues/detail?id=413851 for more discussion |
| 123 | + w.Header().Set("Content-Security-Policy", "default-src 'none'; style-src 'unsafe-inline'") |
| 124 | + } |
| 125 | + |
| 126 | + opts.Disposition = "inline" |
| 127 | + if isSVG && !setting.UI.SVG.Enabled { |
| 128 | + opts.Disposition = "attachment" |
| 129 | + } |
| 130 | + |
| 131 | + ServeSetHeaders(w, opts) |
| 132 | +} |
| 133 | + |
| 134 | +const mimeDetectionBufferLen = 1024 |
| 135 | + |
| 136 | +func ServeContentByReader(r *http.Request, w http.ResponseWriter, filePath string, size int64, reader io.Reader) { |
| 137 | + buf := make([]byte, mimeDetectionBufferLen) |
| 138 | + n, err := util.ReadAtMost(reader, buf) |
| 139 | + if err != nil { |
| 140 | + http.Error(w, "serve content: unable to pre-read", http.StatusRequestedRangeNotSatisfiable) |
| 141 | + return |
| 142 | + } |
| 143 | + if n >= 0 { |
| 144 | + buf = buf[:n] |
| 145 | + } |
| 146 | + setServeHeadersByFile(r, w, filePath, buf) |
| 147 | + |
| 148 | + // reset the reader to the beginning |
| 149 | + reader = io.MultiReader(bytes.NewReader(buf), reader) |
| 150 | + |
| 151 | + rangeHeader := r.Header.Get("Range") |
| 152 | + |
| 153 | + // if no size or no supported range, serve as 200 (complete response) |
| 154 | + if size <= 0 || !strings.HasPrefix(rangeHeader, "bytes=") { |
| 155 | + if size >= 0 { |
| 156 | + w.Header().Set("Content-Length", strconv.FormatInt(size, 10)) |
| 157 | + } |
| 158 | + _, _ = io.Copy(w, reader) // just like http.ServeContent, not necessary to handle the error |
| 159 | + return |
| 160 | + } |
| 161 | + |
| 162 | + // do our best to support the minimal "Range" request (no support for multiple range: "Range: bytes=0-50, 100-150") |
| 163 | + // |
| 164 | + // GET /... |
| 165 | + // Range: bytes=0-1023 |
| 166 | + // |
| 167 | + // HTTP/1.1 206 Partial Content |
| 168 | + // Content-Range: bytes 0-1023/146515 |
| 169 | + // Content-Length: 1024 |
| 170 | + |
| 171 | + _, rangeParts, _ := strings.Cut(rangeHeader, "=") |
| 172 | + rangeBytesStart, rangeBytesEnd, found := strings.Cut(rangeParts, "-") |
| 173 | + start, err := strconv.ParseInt(rangeBytesStart, 10, 64) |
| 174 | + if start < 0 || start >= size { |
| 175 | + err = errors.New("invalid start range") |
| 176 | + } |
| 177 | + if err != nil { |
| 178 | + http.Error(w, err.Error(), http.StatusRequestedRangeNotSatisfiable) |
| 179 | + return |
| 180 | + } |
| 181 | + end, err := strconv.ParseInt(rangeBytesEnd, 10, 64) |
| 182 | + if rangeBytesEnd == "" && found { |
| 183 | + err = nil |
| 184 | + end = size - 1 |
| 185 | + } |
| 186 | + if end >= size { |
| 187 | + end = size - 1 |
| 188 | + } |
| 189 | + if end < start { |
| 190 | + err = errors.New("invalid end range") |
| 191 | + } |
| 192 | + if err != nil { |
| 193 | + http.Error(w, err.Error(), http.StatusBadRequest) |
| 194 | + return |
| 195 | + } |
| 196 | + |
| 197 | + partialLength := end - start + 1 |
| 198 | + w.Header().Set("Content-Range", fmt.Sprintf("bytes %d-%d/%d", start, end, size)) |
| 199 | + w.Header().Set("Content-Length", strconv.FormatInt(partialLength, 10)) |
| 200 | + if _, err = io.CopyN(io.Discard, reader, start); err != nil { |
| 201 | + http.Error(w, "serve content: unable to skip", http.StatusInternalServerError) |
| 202 | + return |
| 203 | + } |
| 204 | + |
| 205 | + w.WriteHeader(http.StatusPartialContent) |
| 206 | + _, _ = io.CopyN(w, reader, partialLength) // just like http.ServeContent, not necessary to handle the error |
| 207 | +} |
| 208 | + |
| 209 | +func ServeContentByReadSeeker(r *http.Request, w http.ResponseWriter, filePath string, modTime time.Time, reader io.ReadSeeker) { |
| 210 | + buf := make([]byte, mimeDetectionBufferLen) |
| 211 | + n, err := util.ReadAtMost(reader, buf) |
| 212 | + if err != nil { |
| 213 | + http.Error(w, "serve content: unable to read", http.StatusInternalServerError) |
| 214 | + return |
| 215 | + } |
| 216 | + if _, err = reader.Seek(0, io.SeekStart); err != nil { |
| 217 | + http.Error(w, "serve content: unable to seek", http.StatusInternalServerError) |
| 218 | + return |
| 219 | + } |
| 220 | + if n >= 0 { |
| 221 | + buf = buf[:n] |
| 222 | + } |
| 223 | + setServeHeadersByFile(r, w, filePath, buf) |
| 224 | + http.ServeContent(w, r, path.Base(filePath), modTime, reader) |
| 225 | +} |
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