A simple http/s file downloader for node.js
npm install node-downloader-helper
$ npm install --save node-downloader-helper
`
Usage
For a more complete example check example folder
`javascript
const { DownloaderHelper } = require('node-downloader-helper');
const dl = new DownloaderHelper('https://proof.ovh.net/files/1Gb.dat', __dirname);
dl.on('end', () => console.log('Download Completed'));
dl.on('error', (err) => console.log('Download Failed', err));
dl.start().catch(err => console.error(err));
`
IMPORTANT NOTE: I highly recommend to use both .on('error') and .start().catch, although they do the same thing, if on('error') is not defined, an error will be thrown when the error event is emitted and not listing, this is because EventEmitter is designed to throw an unhandled error event error if not been listened and is too late to change it now.
$3
This can be used as standalone CLI downloader
Install npm i -g node-downloader-helper
Usage: ndh [folder] [url]
`bash
$ ndh ./folder http://url
`
Options
Download Helper constructor also allow a 3rd parameter to set some options constructor(url, destinationFolder, options),
these are the default values
`javascript
{
body: null, // Request body, can be any, string, object, etc.
method: 'GET', // Request Method Verb
headers: {}, // Custom HTTP Header ex: Authorization, User-Agent
timeout: -1, // Request timeout in milliseconds (-1 use default), is the equivalent of 'httpRequestOptions: { timeout: value }' (also applied to https)
metadata: {}, // custom metadata for the user retrieve later (default:null)
resumeOnIncomplete: true, // Resume download if the file is incomplete (set false if using any pipe that modifies the file)
resumeOnIncompleteMaxRetry: 5, // Max retry when resumeOnIncomplete is true
resumeIfFileExists: false, // it will resume if a file already exists and is not completed, you might want to set removeOnStop and removeOnFail to false. If you used pipe for compression it will produce corrupted files
fileName: string|cb(fileName, filePath, contentType)|{name, ext}, // Custom filename when saved
retry: false, // { maxRetries: number, delay: number in ms } or false to disable (default)
forceResume: false, // If the server does not return the "accept-ranges" header, can be force if it does support it
removeOnStop: true, // remove the file when is stopped (default:true)
removeOnFail: true, // remove the file when fail (default:true)
progressThrottle: 1000, // interval time of the 'progress.throttled' event will be emitted
override: boolean|{skip, skipSmaller}, // Behavior when local file already exists
httpRequestOptions: {}, // Override the http request options
httpsRequestOptions: {}, // Override the https request options, ex: to add SSL Certs
}
`
for body you can provide any parameter accepted by http.request write function req.write(body) https://nodejs.org/api/http.html, when using this, you might need to add the content-length and content-type header in addition with the http method POST or PUT
ex:
`javascript
const data = JSON.stringify({
todo: 'Buy the milk'
});
const dl = new DownloaderHelper('my_url', __dirname, {
method: 'POST',
body: data,
headers: {
'Content-Type': 'application/json',
'Content-Length': data.length
} } );
`
for fileName you can provide 3 types of parameter
- string: will use the full string as the filename including extension
- callback(fileName, filePath, contentType): must return an string, only sync function are supported ex: (fileName) => 'PREFIX_' + fileName;, contentType will be provided if available
- object: this object must contain a name attribute and an optional ext attribute, the ext attribute can be an string without dot(.) or a boolean where true use the name as full file name (same as just giving an string to the fileName parameter) or false (default) will only replace the name and keep the original extension, for example if the original name is myfile.zip and the option is {name: 'somename'} the output will be somename.zip
for override you can provide 2 types of parameter
- boolean: true to override existing local file, false to append '(number)' to new file name
- object: object with properties skip (boolean): whether to skip download if file exists, and skipSmaller (boolean): whether to skip download if file exists but is smaller. Both default to false, for the equivalent of override: true.
for httpRequestOptions the available options are detailed in here https://nodejs.org/api/http.html#http_http_request_options_callback
for httpsRequestOptions the available options are detailed in here https://nodejs.org/api/https.html#https_https_request_options_callback
Methods
| Name | Description |
|---------- |--------------------------------------------------------------------------- |
| start | starts the downloading |
| pause | pause the downloading |
| resume | resume the downloading if supported, if not it will start from the beginning |
| stop | stop the downloading and remove the file |
| pipe | readable.pipe(stream.Readable, options) : stream.Readable |
| unpipe | (stream) if not stream is not specified, then all pipes are detached. |
| updateOptions | (options, url) updates the options, can be use on pause/resume events |
| getStats | returns stats from the current download, these are the same stats sent via progress event |
| getTotalSize | gets the total file size from the server |
| getDownloadPath | gets the full path where the file will be downloaded (available after the start phase) |
| isResumable | return true/false if the download can be resumable (available after the start phase) |
| getResumeState | Get the state required to resume the download after restart. This state can be passed back to resumeFromFile() to resume a download |
| resumeFromFile | resumeFromFile(filePath?: string, state?: IResumeState) Resume the download from a previous file path, if the state is not provided it will try to fetch from the information the headers and filePath, @see resumeIfFileExists option |
usage of resumeFromFile
`javascript
const downloadDir = 'D:/TEMP';
const { DownloaderHelper } = require('node-downloader-helper');
const dl = new DownloaderHelper('https://proof.ovh.net/files/1Gb.dat', downloadDir);
dl.on('end', () => console.log('Download Completed'));
dl.on('error', (err) => console.log('Download Failed', err));
// option 1
const prevFilePath = ${downloadDir}/1Gb.dat;
dl.resumeFromFile(prevFilePath).catch(err => console.error(err));
// option 2
const prevState = dl.getResumeState(); // this should be stored in a file, localStorage, db, etc in a previous process for example on 'stop'
dl.resumeFromFile(prevState.filePath, prevState).catch(err => console.error(err));
`
Events
| Name | Description |
|-------------- |----------------------------------------------------------------------------------- |
| start | Emitted when the .start method is called |
| skip | Emitted when the download is skipped because the file already exists |
| download | Emitted when the download starts callback(downloadInfo) |
| progress | Emitted every time gets data from the server callback(stats) |
| progress.throttled| The same as progress but emits every 1 second while is downloading callback(stats) |
| retry | Emitted when the download fails and retry is enabled callback(attempt, retryOpts, err) |
| end | Emitted when the downloading has finished callback(downloadInfo) |
| error | Emitted when there is any error callback(error) |
| timeout | Emitted when the underlying socket times out from inactivity. |
| pause | Emitted when the .pause method is called |
| stop | Emitted when the .stop method is called |
| resume | Emitted when the .resume method is called callback(isResume) |
| renamed | Emitted when '(number)' is appended to the end of file, this requires override:false opt, callback(filePaths) |
| redirected | Emitted when an url redirect happened callback(newUrl, oldUrl) NOTE: this will be triggered during getTotalSize() as well |
| stateChanged | Emitted when the state changes callback(state) |
| warning | Emitted when an error occurs that was not thrown intentionally callback(err: Error) |
event skip skipInfo object
`javascript
{
totalSize:, // total file size got from the server (will be set as 'null' if content-length header is not available)
fileName:, // original file name
filePath:, // original path name
downloadedSize:, // the downloaded amount
}
`
event download downloadInfo object
`javascript
{
totalSize:, // total file size got from the server (will be set as 'null' if content-length header is not available)
fileName:, // assigned name
filePath:, // download path
isResumed:, // if the download is a resume,
downloadedSize:, // the downloaded amount (only if is resumed otherwise always 0)
}
`
event progress or progress.throttled stats object
`javascript
{
name:, // file name
total:, // total size that needs to be downloaded in bytes, (will be set as 'null' if content-length header is not available)
downloaded:, // downloaded size in bytes
progress:, // progress porcentage 0-100%, (will be set as 0 if total is null)
speed: // download speed in bytes
}
`
event end downloadInfo object
`javascript
{
fileName:,
filePath:,
totalSize:, // total file size got from the server, (will be set as 'null' if content-length header is not available)
incomplete:, // true/false if the download endend but still incomplete, set as 'false' if totalSize is null
onDiskSize, // total size of file on the disk
downloadedSize:, // the total size downloaded
}
`
event renamed filePaths object
`javascript
{
path:, // modified path name
fileName:, // modified file name
prevPath:, // original path name
prevFileName:, // original file name
}
`
event error error object
`javascript
{
message:, // Error message
status:, // Http status response if available
body:, // Http body response if available
}
`
States
| Name | Value |
|-------------- |---------------------------------- |
| IDLE | 'IDLE' |
| SKIPPED | 'SKIPPED' |
| STARTED | 'STARTED' |
| DOWNLOADING | 'DOWNLOADING' |
| PAUSED | 'PAUSED' |
| RESUMED | 'RESUMED' |
| STOPPED | 'STOPPED' |
| FINISHED | 'FINISHED' |
| FAILED | 'FAILED' |
| RETRY | 'RETRY' |
Test
`
$ npm test
``