Container File Blobs#
Pure JS implementation of various container file formats, including ZIP and CFB.
Installation#
In the browser:
<script src="dist/cfb.min.js" type="text/javascript"></script>With npm:
$ npm install cfbThe xlscfb.js file is designed to be embedded in js-xlsx
Library Usage#
In node:
var CFB = require('cfb');For example, to get the Workbook content from an Excel 2003 XLS file:
var cfb = CFB.read(filename, {type: 'file'});
var workbook = CFB.find(cfb, 'Workbook');
var data = workbook.content;Command-Line Utility Usage#
The cfb-cli module ships with a CLI
tool for manipulating and inspecting supported files.
JS API#
TypeScript definitions are maintained in types/index.d.ts.
The CFB object exposes the following methods and properties:
CFB.parse(blob) takes a nodejs Buffer or an array of bytes and returns an
parsed representation of the data.
CFB.read(blob, opts) wraps parse.
CFB.find(cfb, path) performs a case-insensitive match for the path (or file
name, if there are no slashes) and returns an entry object or null if not found.
CFB.write(cfb, opts) generates a file based on the container.
CFB.writeFile(cfb, filename, opts) creates a file with the specified name.
Parse Options#
CFB.read takes an options argument. opts.type controls the behavior:
type | expected input |
|---|---|
"base64" | string: Base64 encoding of the file |
"binary" | string: binary string (byte n is data.charCodeAt(n)) |
"buffer" | nodejs Buffer |
"file" | string: path of file that will be read (nodejs only) |
| (default) | buffer or array of 8-bit unsigned int (byte n is data[n]) |
Write Options#
CFB.write and CFB.writeFile take options argument.
opts.type controls the behavior:
type | output |
|---|---|
"base64" | string: Base64 encoding of the file |
"binary" | string: binary string (byte n is data.charCodeAt(n)) |
"buffer" | nodejs Buffer |
"file" | string: path of file that will be created (nodejs only) |
| (default) | buffer if available, array of 8-bit unsigned int otherwise |
opts.fileType controls the output file type:
fileType | output |
|---|---|
'cfb' (default) | CFB container |
'zip' | ZIP file |
'mad' | MIME aggregate document |
opts.compression enables DEFLATE compression for ZIP file type.
Utility Functions#
The utility functions are available in the CFB.utils object. Functions that
accept a name argument strictly deal with absolute file names:
.cfb_new(?opts)creates a new container object..cfb_add(cfb, name, ?content, ?opts)adds a new file to thecfb.
Set the option{unsafe:true}to skip existence checks (for bulk additions).cfb_del(cfb, name)deletes the specified file.cfb_mov(cfb, old_name, new_name)moves the old file to new path and name.use_zlib(require("zlib"))loads a nodejszlibinstance.
By default, the library uses a pure JS inflate/deflate implementation. NodeJSzlib.InflateRaw exposes the number of bytes read in versions after 8.11.0.
If a supplied zlib does not support the required features, a warning will be
displayed in the console and the pure JS fallback will be used.
Container Object Description#
The objects returned by parse and read have the following properties:
.FullPathsis an array of the names of all of the streams (files) and
storages (directories) in the container. The paths are properly prefixed from
the root entry (so the entries are unique).FileIndexis an array, in the same order as.FullPaths, whose values are
objects following the schema:
interface CFBEntry {
name: string; /** Case-sensitive internal name */
type: number; /** 1 = dir, 2 = file, 5 = root ; see [MS-CFB] 2.6.1 */
content: Buffer | number[] | Uint8Array; /** Raw Content */
ct?: Date; /** Creation Time */
mt?: Date; /** Modification Time */
ctype?: String; /** Content-Type (for MAD) */
}License#
Please consult the attached LICENSE file for details. All rights not explicitly
granted by the Apache 2.0 License are reserved by the Original Author.
References#
MS-CFB: Compound File Binary File Format- ZIP
APPNOTE.TXT: .ZIP File Format Specification - RFC1951: https://www.ietf.org/rfc/rfc1951.txt
- RFC2045: https://www.ietf.org/rfc/rfc2045.txt
- RFC2557: https://www.ietf.org/rfc/rfc2557.txt