mirror of
https://github.com/actions/setup-python.git
synced 2024-11-23 09:17:16 +00:00
156 lines
6.4 KiB
Markdown
156 lines
6.4 KiB
Markdown
## Pure JS character encoding conversion [](https://travis-ci.org/ashtuchkin/iconv-lite)
|
||
|
||
* Doesn't need native code compilation. Works on Windows and in sandboxed environments like [Cloud9](http://c9.io).
|
||
* Used in popular projects like [Express.js (body_parser)](https://github.com/expressjs/body-parser),
|
||
[Grunt](http://gruntjs.com/), [Nodemailer](http://www.nodemailer.com/), [Yeoman](http://yeoman.io/) and others.
|
||
* Faster than [node-iconv](https://github.com/bnoordhuis/node-iconv) (see below for performance comparison).
|
||
* Intuitive encode/decode API
|
||
* Streaming support for Node v0.10+
|
||
* [Deprecated] Can extend Node.js primitives (buffers, streams) to support all iconv-lite encodings.
|
||
* In-browser usage via [Browserify](https://github.com/substack/node-browserify) (~180k gzip compressed with Buffer shim included).
|
||
* Typescript [type definition file](https://github.com/ashtuchkin/iconv-lite/blob/master/lib/index.d.ts) included.
|
||
* React Native is supported (need to explicitly `npm install` two more modules: `buffer` and `stream`).
|
||
* License: MIT.
|
||
|
||
[](https://npmjs.org/packages/iconv-lite/)
|
||
|
||
## Usage
|
||
### Basic API
|
||
```javascript
|
||
var iconv = require('iconv-lite');
|
||
|
||
// Convert from an encoded buffer to js string.
|
||
str = iconv.decode(Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]), 'win1251');
|
||
|
||
// Convert from js string to an encoded buffer.
|
||
buf = iconv.encode("Sample input string", 'win1251');
|
||
|
||
// Check if encoding is supported
|
||
iconv.encodingExists("us-ascii")
|
||
```
|
||
|
||
### Streaming API (Node v0.10+)
|
||
```javascript
|
||
|
||
// Decode stream (from binary stream to js strings)
|
||
http.createServer(function(req, res) {
|
||
var converterStream = iconv.decodeStream('win1251');
|
||
req.pipe(converterStream);
|
||
|
||
converterStream.on('data', function(str) {
|
||
console.log(str); // Do something with decoded strings, chunk-by-chunk.
|
||
});
|
||
});
|
||
|
||
// Convert encoding streaming example
|
||
fs.createReadStream('file-in-win1251.txt')
|
||
.pipe(iconv.decodeStream('win1251'))
|
||
.pipe(iconv.encodeStream('ucs2'))
|
||
.pipe(fs.createWriteStream('file-in-ucs2.txt'));
|
||
|
||
// Sugar: all encode/decode streams have .collect(cb) method to accumulate data.
|
||
http.createServer(function(req, res) {
|
||
req.pipe(iconv.decodeStream('win1251')).collect(function(err, body) {
|
||
assert(typeof body == 'string');
|
||
console.log(body); // full request body string
|
||
});
|
||
});
|
||
```
|
||
|
||
### [Deprecated] Extend Node.js own encodings
|
||
> NOTE: This doesn't work on latest Node versions. See [details](https://github.com/ashtuchkin/iconv-lite/wiki/Node-v4-compatibility).
|
||
|
||
```javascript
|
||
// After this call all Node basic primitives will understand iconv-lite encodings.
|
||
iconv.extendNodeEncodings();
|
||
|
||
// Examples:
|
||
buf = new Buffer(str, 'win1251');
|
||
buf.write(str, 'gbk');
|
||
str = buf.toString('latin1');
|
||
assert(Buffer.isEncoding('iso-8859-15'));
|
||
Buffer.byteLength(str, 'us-ascii');
|
||
|
||
http.createServer(function(req, res) {
|
||
req.setEncoding('big5');
|
||
req.collect(function(err, body) {
|
||
console.log(body);
|
||
});
|
||
});
|
||
|
||
fs.createReadStream("file.txt", "shift_jis");
|
||
|
||
// External modules are also supported (if they use Node primitives, which they probably do).
|
||
request = require('request');
|
||
request({
|
||
url: "http://github.com/",
|
||
encoding: "cp932"
|
||
});
|
||
|
||
// To remove extensions
|
||
iconv.undoExtendNodeEncodings();
|
||
```
|
||
|
||
## Supported encodings
|
||
|
||
* All node.js native encodings: utf8, ucs2 / utf16-le, ascii, binary, base64, hex.
|
||
* Additional unicode encodings: utf16, utf16-be, utf-7, utf-7-imap.
|
||
* All widespread singlebyte encodings: Windows 125x family, ISO-8859 family,
|
||
IBM/DOS codepages, Macintosh family, KOI8 family, all others supported by iconv library.
|
||
Aliases like 'latin1', 'us-ascii' also supported.
|
||
* All widespread multibyte encodings: CP932, CP936, CP949, CP950, GB2312, GBK, GB18030, Big5, Shift_JIS, EUC-JP.
|
||
|
||
See [all supported encodings on wiki](https://github.com/ashtuchkin/iconv-lite/wiki/Supported-Encodings).
|
||
|
||
Most singlebyte encodings are generated automatically from [node-iconv](https://github.com/bnoordhuis/node-iconv). Thank you Ben Noordhuis and libiconv authors!
|
||
|
||
Multibyte encodings are generated from [Unicode.org mappings](http://www.unicode.org/Public/MAPPINGS/) and [WHATWG Encoding Standard mappings](http://encoding.spec.whatwg.org/). Thank you, respective authors!
|
||
|
||
|
||
## Encoding/decoding speed
|
||
|
||
Comparison with node-iconv module (1000x256kb, on MacBook Pro, Core i5/2.6 GHz, Node v0.12.0).
|
||
Note: your results may vary, so please always check on your hardware.
|
||
|
||
operation iconv@2.1.4 iconv-lite@0.4.7
|
||
----------------------------------------------------------
|
||
encode('win1251') ~96 Mb/s ~320 Mb/s
|
||
decode('win1251') ~95 Mb/s ~246 Mb/s
|
||
|
||
## BOM handling
|
||
|
||
* Decoding: BOM is stripped by default, unless overridden by passing `stripBOM: false` in options
|
||
(f.ex. `iconv.decode(buf, enc, {stripBOM: false})`).
|
||
A callback might also be given as a `stripBOM` parameter - it'll be called if BOM character was actually found.
|
||
* If you want to detect UTF-8 BOM when decoding other encodings, use [node-autodetect-decoder-stream](https://github.com/danielgindi/node-autodetect-decoder-stream) module.
|
||
* Encoding: No BOM added, unless overridden by `addBOM: true` option.
|
||
|
||
## UTF-16 Encodings
|
||
|
||
This library supports UTF-16LE, UTF-16BE and UTF-16 encodings. First two are straightforward, but UTF-16 is trying to be
|
||
smart about endianness in the following ways:
|
||
* Decoding: uses BOM and 'spaces heuristic' to determine input endianness. Default is UTF-16LE, but can be
|
||
overridden with `defaultEncoding: 'utf-16be'` option. Strips BOM unless `stripBOM: false`.
|
||
* Encoding: uses UTF-16LE and writes BOM by default. Use `addBOM: false` to override.
|
||
|
||
## Other notes
|
||
|
||
When decoding, be sure to supply a Buffer to decode() method, otherwise [bad things usually happen](https://github.com/ashtuchkin/iconv-lite/wiki/Use-Buffers-when-decoding).
|
||
Untranslatable characters are set to <20> or ?. No transliteration is currently supported.
|
||
Node versions 0.10.31 and 0.11.13 are buggy, don't use them (see #65, #77).
|
||
|
||
## Testing
|
||
|
||
```bash
|
||
$ git clone git@github.com:ashtuchkin/iconv-lite.git
|
||
$ cd iconv-lite
|
||
$ npm install
|
||
$ npm test
|
||
|
||
$ # To view performance:
|
||
$ node test/performance.js
|
||
|
||
$ # To view test coverage:
|
||
$ npm run coverage
|
||
$ open coverage/lcov-report/index.html
|
||
```
|