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https://github.com/Borewit/strtok3
Promise based streaming tokenizer
https://github.com/Borewit/strtok3
binary decoder decoding encoder encoding stream streaming-tokenizer tokenizer
Last synced: 2 months ago
JSON representation
Promise based streaming tokenizer
- Host: GitHub
- URL: https://github.com/Borewit/strtok3
- Owner: Borewit
- License: mit
- Created: 2017-06-18T10:06:00.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2024-10-28T06:48:34.000Z (2 months ago)
- Last Synced: 2024-10-29T16:00:07.336Z (2 months ago)
- Topics: binary, decoder, decoding, encoder, encoding, stream, streaming-tokenizer, tokenizer
- Language: TypeScript
- Size: 3.11 MB
- Stars: 37
- Watchers: 3
- Forks: 15
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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# strtok3
A promise based streaming [*tokenizer*](#tokenizer-object) for [Node.js](http://nodejs.org) and browsers.
The `strtok3` module provides several methods for creating a [*tokenizer*](#tokenizer-object) from various input sources.
Designed for:
* Seamless support in streaming environments.
* Efficiently decode binary data, strings, and numbers.
* Reading [predefined](https://github.com/Borewit/token-types) or custom tokens.
* Offering [*tokenizers*](#tokenizer-object) for reading from [files](#method-strtok3fromfile), [streams](#fromstream-function) or [Uint8Arrays](#frombuffer-function).
### Features
`strtok3` can read from:
* Files, using a file path as input.
* Node.js [streams](https://nodejs.org/api/stream.html).
* [Buffer](https://nodejs.org/api/buffer.html) or [Uint8Array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array).
* HTTP chunked transfer provided by [@tokenizer/http](https://github.com/Borewit/tokenizer-http).
* [Amazon S3](https://aws.amazon.com/s3) chunks with [@tokenizer/s3](https://github.com/Borewit/tokenizer-s3).
## Installation
```sh
npm install strtok3
```
### Compatibility
Starting with version 7, the module has migrated from [CommonJS](https://en.wikipedia.org/wiki/CommonJS) to [pure ECMAScript Module (ESM)](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c).
The distributed JavaScript codebase is compliant with the [ECMAScript 2020 (11th Edition)](https://en.wikipedia.org/wiki/ECMAScript_version_history#11th_Edition_%E2%80%93_ECMAScript_2020) standard.
> [!NOTE]
> This module requires a [Node.js ≥ 16](https://nodejs.org/en/about/previous-releases) engine.
> It can also be used in a browser environment when bundled with a module bundler.
## Support the Project
If you find this project useful and would like to support its development, consider sponsoring or contributing:
- [Become a sponsor to Borewit](https://github.com/sponsors/Borewit)
- Buy me a coffee:
## API Documentation
### strtok3 methods
Use one of the methods to instantiate an [*abstract tokenizer*](#tokenizer-object):
- [fromFile](#fromfile-function)[^1]
- [fromStream](#fromstream-function)[^1]
- [fromWebStream](#fromwebstream-function)
- [fromBuffer](#frombuffer-function)
[^1]: Only available when importing this module with Node.js
All methods return a [`Tokenizer`](#tokenizer-object), either directly or via a promise.
#### `fromFile` function
Creates a [*tokenizer*](#tokenizer-object) from a local file.
```ts
function fromFile(sourceFilePath: string): Promise
```
| Parameter | Type | Description |
|----------------|----------|----------------------------|
| sourceFilePath | `string` | Path to file to read from |
> [!NOTE]
> - Only available for Node.js engines
> - `fromFile` automatically embeds [file-information](#file-information)
Returns, via a promise, a [*tokenizer*](#tokenizer-object) which can be used to parse a file.
```js
import * as strtok3 from 'strtok3';
import * as Token from 'token-types';
(async () => {
const tokenizer = await strtok3.fromFile("somefile.bin");
try {
const myNumber = await tokenizer.readToken(Token.UINT8);
console.log(`My number: ${myNumber}`);
} finally {
tokenizer.close(); // Close the file
}
})();
```
#### `fromStream` function
Creates a [*tokenizer*](#tokenizer-object) from a Node.js [readable stream](https://nodejs.org/api/stream.html#stream_class_stream_readable).
```ts
function fromStream(stream: Readable, options?: ITokenizerOptions): Promise
```
| Parameter | Optional | Type | Description |
|-----------|-----------|-------------------------|--------------------------|
| stream | no | [Readable](https://nodejs.org/api/stream.html#stream_class_stream_readable) | Stream to read from |
| fileInfo | yes | [IFileInfo](#IFileInfo) | Provide file information |
Returns a Promise providing a [*tokenizer*](#tokenizer-object).
> [!NOTE]
> - Only available for Node.js engines
#### `fromWebStream` function
Creates [*tokenizer*](#tokenizer-object) from a [WHATWG ReadableStream](https://nodejs.org/api/webstreams.html#web-streams-api).
```ts
function fromWebStream(webStream: AnyWebByteStream, options?: ITokenizerOptions): ReadStreamTokenizer
```
| Parameter | Optional | Type | Description |
|----------------|-----------|--------------------------------------------------------------------------|------------------------------------|
| readableStream | no | [ReadableStream](https://nodejs.org/api/webstreams.html#web-streams-api) | WHATWG ReadableStream to read from |
| fileInfo | yes | [IFileInfo](#IFileInfo) | Provide file information |
Returns a Promise providing a [*tokenizer*](#tokenizer-object)
```js
import strtok3 from 'strtok3';
import * as Token from 'token-types';
strtok3.fromWebStream(readableStream).then(tokenizer => {
return tokenizer.readToken(Token.UINT8).then(myUint8Number => {
console.log(`My number: ${myUint8Number}`);
});
});
```
#### `fromBuffer()` function
Create a tokenizer from memory ([Uint8Array](https://nodejs.org/api/buffer.html)).
```ts
function fromBuffer(uint8Array: Uint8Array, options?: ITokenizerOptions): BufferTokenizer
```
| Parameter | Optional | Type | Description |
|------------|----------|--------------------------------------------------|----------------------------------------|
| uint8Array | no | [Uint8Array](https://nodejs.org/api/buffer.html) | Uint8Array or Buffer to read from |
| fileInfo | yes | [IFileInfo](#IFileInfo) | Provide file information |
Returns a Promise providing a [*tokenizer*](#tokenizer-object).
```js
import * as strtok3 from 'strtok3';
const tokenizer = strtok3.fromBuffer(buffer);
tokenizer.readToken(Token.UINT8).then(myUint8Number => {
console.log(`My number: ${myUint8Number}`);
});
```
### `Tokenizer` object
The *tokenizer* is an abstraction of a [stream](https://nodejs.org/api/stream.html), file or [Uint8Array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array), allowing _reading_ or _peeking_ from the stream.
It can also be translated in chunked reads, as done in [@tokenizer/http](https://github.com/Borewit/tokenizer-http);
#### Key Features:
- Supports seeking within the stream using `tokenizer.ignore()`.
- Offers `peek` methods to preview data without advancing the read pointer.
- Maintains the read position via tokenizer.position.
#### Tokenizer functions
_Read_ methods advance the stream pointer, while _peek_ methods do not.
There are two kind of functions:
1. *read* methods: used to read a *token* of [Buffer](https://nodejs.org/api/buffer.html) from the [*tokenizer*](#tokenizer-object). The position of the *tokenizer-stream* will advance with the size of the token.
2. *peek* methods: same as the read, but it will *not* advance the pointer. It allows to read (peek) ahead.
#### `readBuffer` function
Read data from the _tokenizer_ into provided "buffer" (`Uint8Array`).
`readBuffer(buffer, options?)`
```ts
readBuffer(buffer: Uint8Array, options?: IReadChunkOptions): Promise;
```
| Parameter | Type | Description |
|------------|----------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| buffer | [Buffer](https://nodejs.org/api/buffer.html) | Uint8Array | Target buffer to write the data read to |
| options | [IReadChunkOptions](#ireadchunkoptions) | An integer specifying the number of bytes to read |
Return promise with number of bytes read.
The number of bytes read maybe if less, *mayBeLess* flag was set.
#### `peekBuffer` function
Peek (read ahead), from [*tokenizer*](#tokenizer-object), into the buffer without advancing the stream pointer.
```ts
peekBuffer(uint8Array: Uint8Array, options?: IReadChunkOptions): Promise;
```
| Parameter | Type | Description |
|------------|-----------------------------------------|-----------------------------------------------------|
| buffer | Buffer | Uint8Array | Target buffer to write the data read (peeked) to. |
| options | [IReadChunkOptions](#ireadchunkoptions) | An integer specifying the number of bytes to read. | |
Return value `Promise` Promise with number of bytes read. The number of bytes read maybe if less, *mayBeLess* flag was set.
#### `readToken` function
Read a *token* from the tokenizer-stream.
```ts
readToken(token: IGetToken, position: number = this.position): Promise
```
| Parameter | Type | Description |
|------------|-------------------------|---------------------------------------------------------------------------------------------------------------------- |
| token | [IGetToken](#IGetToken) | Token to read from the tokenizer-stream. |
| position? | number | Offset where to begin reading within the file. If position is null, data will be read from the current file position. |
Return value `Promise`. Promise with number of bytes read. The number of bytes read maybe if less, *mayBeLess* flag was set.
#### `peek` function
Peek a *token* from the [*tokenizer*](#tokenizer-object).
```ts
peekToken(token: IGetToken, position: number = this.position): Promise
```
| Parameter | Type | Description |
|------------|----------------------------|-------------------------------------------------------------------------------------------------------------------------|
| token | [IGetToken](#IGetToken) | Token to read from the tokenizer-stream. |
| position? | number | Offset where to begin reading within the file. If position is null, data will be read from the current file position. |
Return a promise with the token value peeked from the [*tokenizer*](#tokenizer-object).
#### `readNumber` function
Peek a numeric [*token*](#token) from the [*tokenizer*](#tokenizer-object).
```ts
readNumber(token: IToken): Promise
```
| Parameter | Type | Description |
|------------|---------------------------------|----------------------------------------------------|
| token | [IGetToken](#IGetToken) | Numeric token to read from the tokenizer-stream. |
Returns a promise with the decoded numeric value from the *tokenizer-stream*.
#### `ignore` function
Advance the offset pointer with the token number of bytes provided.
```ts
ignore(length: number): Promise
```
| Parameter | Type | Description |
|------------|--------|----------------------------------------------------------------------|
| ignore | number | Numeric of bytes to ignore. Will advance the `tokenizer.position` |
Returns a promise with the decoded numeric value from the *tokenizer-stream*.
#### `close` function
Clean up resources, such as closing a file pointer if applicable.
#### `Tokenizer` attributes
- `fileInfo`
Optional attribute describing the file information, see [IFileInfo](#IFileInfo)
- `position`
Pointer to the current position in the [*tokenizer*](#tokenizer-object) stream.
If a *position* is provided to a _read_ or _peek_ method, is should be, at least, equal or greater than this value.
### `IReadChunkOptions` interface
Each attribute is optional:
| Attribute | Type | Description |
|-----------|---------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| offset | number | The offset in the buffer to start writing at; if not provided, start at 0 |
| length | number | Requested number of bytes to read. |
| position | number | Position where to peek from the file. If position is null, data will be read from the [current file position](#attribute-tokenizerposition). Position may not be less then [tokenizer.position](#attribute-tokenizerposition) |
| mayBeLess | boolean | If and only if set, will not throw an EOF error if less then the requested *mayBeLess* could be read. |
Example usage:
```js
tokenizer.peekBuffer(buffer, {mayBeLess: true});
```
### `IFileInfo` interface
Provides optional metadata about the file being tokenized.
| Attribute | Type | Description |
|-----------|---------|---------------------------------------------------------------------------------------------------|
| size | number | File size in bytes |
| mimeType | number | [MIME-type](https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types) of file. |
| path | number | File path |
| url | boolean | File URL |
### `Token` object
The *token* is basically a description what to read form the [*tokenizer-stream*](#tokenizer-object).
A basic set of *token types* can be found here: [*token-types*](https://github.com/Borewit/token-types).
A token is something which implements the following interface:
```ts
export interface IGetToken {
/**
* Length in bytes of encoded value
*/
len: number;
/**
* Decode value from buffer at offset
* @param buf Buffer to read the decoded value from
* @param off Decode offset
*/
get(buf: Uint8Array, off: number): T;
}
```
The *tokenizer* reads `token.len` bytes from the *tokenizer-stream* into a Buffer.
The `token.get` will be called with the Buffer. `token.get` is responsible for conversion from the buffer to the desired output type.
### Working with Web-API readable stream
To convert a [Web-API readable stream](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamDefaultReader) into a [Node.js readable stream]((https://nodejs.org/api/stream.html#stream_readable_streams)), you can use [readable-web-to-node-stream](https://github.com/Borewit/readable-web-to-node-stream) to convert one in another.
```js
import { fromWebStream } strtok3 from 'strtok3';
import { ReadableWebToNodeStream } from 'readable-web-to-node-stream';
(async () => {
const response = await fetch(url);
const readableWebStream = response.body; // Web-API readable stream
const webStream = new ReadableWebToNodeStream(readableWebStream); // convert to Node.js readable stream
const tokenizer = fromWebStream(webStream); // And we now have tokenizer in a web environment
})();
```
## Dependencies
The diagram below illustrates the primary dependencies of `strtok3`:
```mermaid
graph TD;
S(strtok3)-->P(peek-readable)
S(strtok3)-->TO("@tokenizer/token")
```
-
- [peek-readable](https://github.com/Borewit/peek-readable): Manages reading operations with peeking capabilities, allowing data to be previewed without advancing the read pointer.
- [@tokenizer/token](https://github.com/Borewit/tokenizer-token): Provides token definitions and utilities used by `strtok3` for interpreting binary data.
## Licence
(The MIT License)
Copyright (c) 2024 Borewit
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.