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https://github.com/roccomuso/price-monitoring
Node.js price monitoring library, leveraging the power of x-ray and nightmare.
https://github.com/roccomuso/price-monitoring
alert comparison crawler javascript monitoring nodejs price-tracker
Last synced: 8 days ago
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Node.js price monitoring library, leveraging the power of x-ray and nightmare.
- Host: GitHub
- URL: https://github.com/roccomuso/price-monitoring
- Owner: roccomuso
- License: mit
- Created: 2017-04-29T18:54:32.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2019-10-27T09:55:52.000Z (about 5 years ago)
- Last Synced: 2024-10-24T13:51:54.793Z (12 days ago)
- Topics: alert, comparison, crawler, javascript, monitoring, nodejs, price-tracker
- Language: JavaScript
- Size: 24.4 KB
- Stars: 53
- Watchers: 8
- Forks: 7
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# price-monitoring [](https://www.npmjs.com/package/price-monitoring) [](https://standardjs.com)
Node.js price monitoring library, leveraging the power of x-ray and nightmare.
## Features
- [x] Leverage the power of [x-ray](https://github.com/lapwinglabs/x-ray), [nightmare](https://github.com/segmentio/nightmare) and [cheerio](https://github.com/cheeriojs/cheerio).
- [x] Electron based headless-engine that accepts JS and follows redirects.
- [x] Parse Products starting from a CSV file.
- [x] Modular structure for Website parser (`MyEcommerce` that extends `SiteParser`).
- [x] Bind every URL to an instance of the parsers. (A parser can handle multiple urls).
- [x] Check wether an url got his parser.
## Install
$ npm install --save price-monitoring
## Usage
### Product structure
```json
{
"name": "Samsung Evo microSD 32GB",
"link": "https://www.amazon.it/Samsung-MB-MP32DA-EU-Memoria-Adattatore/dp/B00J29BR3Y/",
"price": 14.00,
"variation": 10
}
```
- **name**: product name or identifier.
- **link**: absolute link to the product.
- **price**: base price.
- **variation**: price variation in % that triggers the `priceAlert` event.
- **customSelector**: [optional] provide a custom selector for a given product instead of using the one of your custom parser.
### Get it from a CSV
You can easily provide a CSV list of products.
```text
name, link, price, variation
Samsung Evo microSD 32GB,https://www.amazon.it/Samsung-MB-MP32DA-EU-Memoria-Adattatore/dp/B00J29BR3Y/,14.00,10
...
```
### Main flow
```javascript
var PriceMonitoring = require('price-monitoring')
var pm = new PriceMonitoring({
parsersDir: path.join(__dirname, 'myParsers/'), // add parsers
interval: 60 * 1000 // check prices every min
})
pm.on('priceAlert', function(product, newPrice){
// do whatever you want
// ...
})
/* Add the products from CSV */
pm.parseCSV(fileInput) // fileInput can be a csv file path or a Buffer
// or manually
pm.parseAndSubmit({
name: 'Special price product',
link: 'https://www.amazon.it/dp/B01MY76N2U?psc=1',
price: 249.99,
variation: 18
})
pm.watchPrices()
```
**Every parser works in Parallel, and products prices are fetched sequentially.**
The `parsersDir` property is mandatory.
Check out a fully-working sample in the `example/` dir.
## API
#### parseAndSubmit(``, ``)
Parse and submit a product to his own parser instance. The product object should follow the structure explained above. The callback will return `true` or `false` depending on the submission outcome.
#### removeProduct(``/``, ``)
Remove the product from his own parser instance matching the given product obj or link. The callback will return `true` or `false` if the product link match a registered parser.
#### parseCSV(``/``)
Fetch and parse all the products from the provided CSV file or Buffer. It returns a Promise.
#### fetchAllPrices(cb)
The `cb` is called once all the prices for all the Parsers have been retrieved.
#### watchPrices(cb)
Start watching for Prices, the `callback` is called once all the parsers retrieved all the products prices. The callback returns the current round number. If called multiple times it will not take effect.
#### isWatchingPrices()
Returns `true` if the price watch operation is running, `false` otherwise.
#### stop()
Stop the prices' watch.
#### close()
Close all the nightmareDrivers from the parsers' instances. (This avoids zombie processes).
#### getParsersList()
Returns an Array of the all the Parsers loaded in the current instance of `PriceMonitoring` with all the submitted products.
#### getParsersCount()
Returns the number of site-parsers loaded.
#### getProductsCount()
Returns the number of products added.
#### getProducts()
Returns an array of all the inserted products.
#### isWebsiteCovered(``)
Check wether a given website url has his own parser loaded or not.
## Events
#### .on('error', cb)
Triggered in case of error. `cb` accepts one param, `error`.
#### .on('submit', cb)
Triggered when a new product is submitted in a parser' instance.
The `cb` accepts one param, `product`. (The product being submitted).
#### .on('skip', cb)
Triggered when a product is skipped (no suitable parser found).
The `cb` accepts one param, `product`. (The product being skipped).
#### .on('priceFetched', cb)
Triggered when a new price has been fetched for a given product.
The `cb` accepts 2 params: `product`, `price`.
#### .on('priceAlert', cb)
Triggered when a product's price is outside the variation% threshold.
The `cb` accepts 2 params: `product`, `newPrice`.
#### .on('parserEnd', cb)
Called when a parser ends his price-fetch process for all his products.
The `cb` accepts 2 params: `site`, `nProducts`. Respectively the website and the number of products involved.
## Build a custom website parser
It's quick:
```javascript
const SiteParser = require('price-monitoring').SiteParser
/* Class */
class MyEcommerce extends SiteParser {
constructor () {
super(
'https://www.my-ecommerce-website.com', // base url
'.pricing .price@html | trim | slice:-5 | replaceComma | float' // price selector
)
}
}
module.exports = MyEcommerce
```
That's it. Then don't forget to put your parsers in a directory and give it as `parsersDir` property to your currente `PriceMonitoring` instance.
#### Available filters
- `trim`: trim the given string.
- `reverse`: reverse the given string.
- `join:`: join the string using the given `sep` separator.
- `slice:,`: split the string from `start` to `end` indexes.
- `split:,`: split for the given `sep` separator and return the elem. at the `index`.
- `replaceComma`: Replace the `,` char with `.`, useful to make the price string parsable.
- `float`: Cast the given string to float.
### Test our website parser in an isolate-manner
```javascript
var p = new AmazonIT()
p.on('error', console.log)
p.on('submit', console.log)
p.on('priceFetched', function(product, currentPrice){
console.log(product.name, 'got', currentPrice)
})
p.on('priceAlert', function(product, newPrice){
console.log('Alert!', product.name, 'got', newPrice)
})
p.on('end', function(){
console.log('End!')
})
p.addProduct({
name: 'Special price product',
link: 'https://www.amazon.it/dp/B01MY76N2U?psc=1',
price: 20.5,
variation: 15
})
.addProduct({
name: 'Normal price product',
link: 'https://www.amazon.it/Samsung-MB-MP32DA-EU-Memoria-Adattatore/dp/B00J29BR3Y/',
price: 14.00,
variation: 17
})
.fetchPrices()
```
## Notes
Still in Beta
## Author
Rocco Musolino
## License
MIT