feat: add price range filter (#26)
To avoid scalpers' price, the bot now understand filters on prices
using a minimum and maximum value, in a currency and a pattern to
detect the model.
Example:
```
"price_ranges": [
{"model": "3090", "max": 3000, "currency": "EUR"},
{"model": "3080", "max": 1600, "currency": "EUR"},
{"model": "3070", "max": 1200, "currency": "EUR"}
],
```
More details in README.md.
Signed-off-by: Julien Riou <julien@riou.xyz>
This commit is contained in:
parent
ba791435b7
commit
da532104f8
9 changed files with 231 additions and 28 deletions
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@ -172,6 +172,7 @@ Options:
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* `enable_replies`: reply to original message when product is not available anymore
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* `include_regex` (optional): include products with a name matching this regexp
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* `exclude_regex` (optional): exclude products with a name matching this regexp
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* `price_ranges` (optional): define price ranges for products based on the model. List of rules containing `model` (regex to apply to the product name, string), `min` (minimum expected price, float), `max` (maximum expected price, float), `currency` (price currency used by the filter, string). For example `{"price_ranges":[{"model": "3090", "min": 0, "max": 3000, "currency": "EUR"}]}`
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* `browser_address` (optional): set headless browser address (ex: `http://127.0.0.1:9222`)
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* `api` (optional):
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* `address`: listen address for the REST API (ex: `127.0.0.1:8000`)
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@ -16,6 +16,7 @@ type Config struct {
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URLs []string `json:"urls"`
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IncludeRegex string `json:"include_regex"`
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ExcludeRegex string `json:"exclude_regex"`
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PriceRanges []PriceRange `json:"price_ranges"`
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BrowserAddress string `json:"browser_address"`
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}
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@ -65,6 +66,14 @@ type AmazonConfig struct {
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AffiliateLinks bool `json:"affiliate_links"`
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}
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// PriceRange to store rules to filter products with price outside of the range
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type PriceRange struct {
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Model string `json:"model"`
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Min float64 `json:"min"`
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Max float64 `json:"max"`
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Currency string `json:"currency"`
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}
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// NewConfig creates a Config struct
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func NewConfig() *Config {
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return &Config{}
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96
currency_converter.go
Normal file
96
currency_converter.go
Normal file
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@ -0,0 +1,96 @@
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package main
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import (
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"encoding/json"
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"fmt"
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"io/ioutil"
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"net/http"
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"strings"
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log "github.com/sirupsen/logrus"
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)
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// CurrencyConverter to cache rates of different currency pairs
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type CurrencyConverter struct {
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rates map[string]float64
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}
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// NewCurrencyConverter to create a CurrencyConverter
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func NewCurrencyConverter() *CurrencyConverter {
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return &CurrencyConverter{
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rates: make(map[string]float64),
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}
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}
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// Convert an amount in a given currency to another currency
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// Eventually fetch rate from a remote API then cache the result
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func (c *CurrencyConverter) Convert(amount float64, fromCurrency string, toCurrency string) (float64, error) {
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var err error
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if fromCurrency == toCurrency {
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return amount, nil
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}
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// exclude invalid currencies
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if fromCurrency == "" || toCurrency == "" {
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return 0.0, fmt.Errorf("invalid currency pair used for convertion (from='%s', to='%s')", fromCurrency, toCurrency)
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}
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// searching currency pair rate in cache
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pair := fmt.Sprintf("%s%s", strings.ToLower(fromCurrency), strings.ToLower(toCurrency))
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rate, exists := c.rates[pair]
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if !exists {
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// fetching rate from api
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rate, err = c.getRate(fromCurrency, toCurrency)
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if err != nil {
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return 0.0, err
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}
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// store rate in cache
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c.rates[pair] = rate
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}
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return rate * amount, nil
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}
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// CurrencyResponse to unmarshall JSON response from API
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type CurrencyResponse struct {
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Date string `json:"date"`
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Rate float64 `json:"rate"`
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}
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// getRate retreives rate from a remote API
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func (c *CurrencyConverter) getRate(fromCurrency string, toCurrency string) (float64, error) {
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if fromCurrency == "" || toCurrency == "" {
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return 0.0, fmt.Errorf("invalid currency pair used for convertion (from=%s, to=%s)", fromCurrency, toCurrency)
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}
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// lowering currency names to match the API route
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fromCurrency = strings.ToLower(fromCurrency)
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toCurrency = strings.ToLower(toCurrency)
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log.Debugf("fetching %s%s rate from currency api", fromCurrency, toCurrency)
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resp, err := http.Get("https://cdn.jsdelivr.net/gh/fawazahmed0/currency-api@1/latest/currencies/" + fromCurrency + "/" + toCurrency + ".json")
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if err != nil {
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return 0.0, fmt.Errorf("could not retreive currency rates for pair %s%s: %s", fromCurrency, toCurrency, err)
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}
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defer resp.Body.Close()
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body, err := ioutil.ReadAll(resp.Body)
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if err != nil {
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return 0.0, fmt.Errorf("could not parse currency rates response for pair %s%s: %s", fromCurrency, toCurrency, err)
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}
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// response has a dynamic name for the rate
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// -> {"date": "2021-05-22", "usd": 1.218125}
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// making it predictable
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// -> {"date": "2021-05-22", "rate": 1.218125}}
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bodyParsed := strings.Replace(string(body), toCurrency, "rate", 1)
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var response CurrencyResponse
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err = json.Unmarshal([]byte(bodyParsed), &response)
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if err != nil {
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return 0.0, err
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}
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return response.Rate, nil
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}
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44
currency_converter_test.go
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44
currency_converter_test.go
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@ -0,0 +1,44 @@
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package main
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import (
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"fmt"
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"testing"
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"github.com/jarcoal/httpmock"
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)
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func TestCurrencyConverterConvert(t *testing.T) {
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httpmock.Activate()
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defer httpmock.DeactivateAndReset()
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httpmock.RegisterResponder("GET", "https://cdn.jsdelivr.net/gh/fawazahmed0/currency-api@1/latest/currencies/eur/chf.json",
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httpmock.NewStringResponder(200, `{"date": "2021-05-22", "chf": 1.093894}`))
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tests := []struct {
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amount float64
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source string
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destination string
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expected float64
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}{
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{1.0, "EUR", "EUR", 1.0}, // same currency (EUR/EUR)
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{1.0, "EUR", "CHF", 1.093894}, // different currency (EUR/CHF)
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{1.0, "EUR", "CHF", 1.093894}, // different currency (EUR/CHF) with cache
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}
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converter := NewCurrencyConverter()
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for i, tc := range tests {
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t.Run(fmt.Sprintf("TestCurrencyConverterConvert#%d", i), func(t *testing.T) {
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converted, err := converter.Convert(tc.amount, tc.source, tc.destination)
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if err != nil {
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t.Errorf("could not convert %.2f from %s to %s: %s", tc.amount, tc.source, tc.destination, err)
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} else if converted != tc.expected {
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t.Errorf("to convert %.2f from %s to %s, got '%.2f', want '%.2f'", tc.amount, tc.source, tc.destination, converted, tc.expected)
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} else {
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t.Logf("to convert %.2f from %s to %s, got '%.2f', want '%.2f'", tc.amount, tc.source, tc.destination, converted, tc.expected)
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}
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})
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}
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}
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@ -6,15 +6,20 @@ import (
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log "github.com/sirupsen/logrus"
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)
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// DefaultCurrency to fallback when no currency is provided
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const DefaultCurrency = "USD"
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// RangeFilter to store the pattern to match product model and price limits
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type RangeFilter struct {
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model *regexp.Regexp
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min float64
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max float64
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currency string
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converter *CurrencyConverter
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}
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// NewRangeFilter to create a RangeFilter
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func NewRangeFilter(regex string, min float64, max float64) (*RangeFilter, error) {
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func NewRangeFilter(regex string, min float64, max float64, currency string, converter *CurrencyConverter) (*RangeFilter, error) {
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var err error
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var compiledRegex *regexp.Regexp
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@ -26,23 +31,56 @@ func NewRangeFilter(regex string, min float64, max float64) (*RangeFilter, error
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}
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}
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var detectedCurrency string
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if currency != "" {
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detectedCurrency = currency
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} else {
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detectedCurrency = DefaultCurrency
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}
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return &RangeFilter{
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model: compiledRegex,
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min: min,
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max: max,
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converter: converter,
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currency: detectedCurrency,
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}, nil
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}
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// Include returns false when a product name matches the model regex and price is outside of the range
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// implements the Filter interface
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func (f *RangeFilter) Include(product *Product) bool {
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// include products with a missing model regex
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if f.model == nil {
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log.Debugf("product %s included because range filter model is missing", product.Name)
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return true
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}
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if f.model.MatchString(product.Name) && product.Price < f.min || product.Price > f.max {
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log.Debugf("product %s excluded because price for the model is outside of the range [%.2f-%.2f]", product.Name, f.min, f.max)
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// include products with a different model
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if !f.model.MatchString(product.Name) {
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log.Debugf("product %s included because range filter model hasn't been detected in the product name", product.Name)
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return true
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}
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// convert price to the filter currency
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convertedPrice, err := f.converter.Convert(product.Price, product.PriceCurrency, f.currency)
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if err != nil {
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log.Warnf("could not convert price %.2f %s to %s for range filter: %s", product.Price, product.PriceCurrency, f.currency, err)
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return true
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}
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// include prices with unlimited maximum if min is respected
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if f.max == 0 && convertedPrice > f.max && f.min <= convertedPrice {
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log.Debugf("product %s included because max value is unlimited and converted price of %.2f%s is higher than lower limit of %.2f%s", product.Name, convertedPrice, f.currency, f.min, f.currency)
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return true
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}
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// include prices inside the range
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if f.min <= convertedPrice && convertedPrice <= f.max {
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log.Debugf("product %s included because range filter model matches and converted price is inside of the range", product.Name)
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return true
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}
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log.Debugf("product %s excluded because range filter model matches and converted price is outside of the range", product.Name)
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return false
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}
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log.Debugf("product %s included because price range filter is not applicable", product.Name)
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return true
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}
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@ -7,36 +7,38 @@ import (
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func TestRangeFilter(t *testing.T) {
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tests := []struct {
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name string // product name
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price float64 // product price
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product *Product
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model string // model regex to apply on the product name
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min float64 // minimum price
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max float64 // maximum price
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currency string // price currency
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included bool // should be included or not
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}{
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{"MSI GeForce RTX 3090 GAMING X", 99.99, "3090", 50.0, 100.0, true}, // model match and price is in the range, should be included
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{"MSI GeForce RTX 3090 GAMING X", 99.99, "3080", 50.0, 100.0, true}, // model doesn't match, should be included
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{"MSI GeForce RTX 3090 GAMING X", 999.99, "3090", 50.0, 100.0, false}, // model match and price is outside of the range, shoud not be included
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{"MSI GeForce RTX 3090 GAMING X", 99.99, "", 50.0, 100.0, true}, // model regex is missing, should be included
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{&Product{Name: "MSI GeForce RTX 3090 GAMING X", Price: 99.99, PriceCurrency: "EUR"}, "3090", 50.0, 100.0, "EUR", true}, // model match and price is in the range, should be included
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{&Product{Name: "MSI GeForce RTX 3090 GAMING X", Price: 99.99, PriceCurrency: "EUR"}, "3080", 50.0, 100.0, "EUR", true}, // model doesn't match, should be included
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{&Product{Name: "MSI GeForce RTX 3090 GAMING X", Price: 999.99, PriceCurrency: "EUR"}, "3090", 50.0, 100.0, "EUR", false}, // model match and price is outside of the range, shoud not be included
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{&Product{Name: "MSI GeForce RTX 3090 GAMING X", Price: 99.99, PriceCurrency: "EUR"}, "", 50.0, 100.0, "EUR", true}, // model regex is missing, should be included
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{&Product{Name: "MSI GeForce RTX 3090 GAMING X", Price: 99.99, PriceCurrency: "EUR"}, "3090", 50.0, 0.0, "EUR", true}, // upper limit is missing, should be included
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}
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converter := NewCurrencyConverter()
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for i, tc := range tests {
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t.Run(fmt.Sprintf("TestRangeFilter#%d", i), func(t *testing.T) {
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product := &Product{Name: tc.name, Price: tc.price}
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filter, err := NewRangeFilter(tc.model, tc.min, tc.max)
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filter, err := NewRangeFilter(tc.model, tc.min, tc.max, tc.currency, converter)
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if err != nil {
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t.Errorf("cannot create filter with model regex '%s' and price range [%.2f, %.2f]: %s", tc.model, tc.min, tc.max, err)
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}
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included := filter.Include(product)
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included := filter.Include(tc.product)
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if included != tc.included {
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t.Errorf("product '%s' with model regex '%s' and range [%.2f, %.2f]: got included=%t, want included=%t", tc.name, tc.model, tc.min, tc.max, included, tc.included)
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t.Errorf("product '%s' of price %.2f%s with model regex '%s' and range [%.2f, %.2f]: got included=%t, want included=%t", tc.product.Name, tc.product.Price, tc.product.PriceCurrency, tc.model, tc.min, tc.max, included, tc.included)
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} else {
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if included {
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t.Logf("product '%s' included by model regex '%s' and range [%.2f, %.2f]", tc.name, tc.model, tc.min, tc.max)
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t.Logf("product '%s' included by model regex '%s' and range [%.2f, %.2f]", tc.product.Name, tc.model, tc.min, tc.max)
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} else {
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t.Logf("product '%s' excluded by model regex '%s' and range [%.2f, %.2f]", tc.name, tc.model, tc.min, tc.max)
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t.Logf("product '%s' excluded by model regex '%s' and range [%.2f, %.2f]", tc.product.Name, tc.model, tc.min, tc.max)
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}
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}
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1
go.mod
1
go.mod
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@ -8,6 +8,7 @@ require (
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github.com/dghubble/oauth1 v0.7.0
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github.com/go-telegram-bot-api/telegram-bot-api/v5 v5.0.0-rc1
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github.com/gorilla/mux v1.8.0
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github.com/jarcoal/httpmock v1.0.8 // indirect
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github.com/sirupsen/logrus v1.8.0
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github.com/spiegel-im-spiegel/pa-api v0.9.0
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gorm.io/driver/mysql v1.0.5
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2
go.sum
2
go.sum
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@ -115,6 +115,8 @@ github.com/jackc/puddle v0.0.0-20190608224051-11cab39313c9/go.mod h1:m4B5Dj62Y0f
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github.com/jackc/puddle v1.1.0/go.mod h1:m4B5Dj62Y0fbyuIc15OsIqK0+JU8nkqQjsgx7dvjSWk=
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github.com/jackc/puddle v1.1.1/go.mod h1:m4B5Dj62Y0fbyuIc15OsIqK0+JU8nkqQjsgx7dvjSWk=
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github.com/jackc/puddle v1.1.3/go.mod h1:m4B5Dj62Y0fbyuIc15OsIqK0+JU8nkqQjsgx7dvjSWk=
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github.com/jarcoal/httpmock v1.0.8 h1:8kI16SoO6LQKgPE7PvQuV+YuD/inwHd7fOOe2zMbo4k=
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github.com/jarcoal/httpmock v1.0.8/go.mod h1:ATjnClrvW/3tijVmpL/va5Z3aAyGvqU3gCT8nX0Txik=
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github.com/jinzhu/inflection v1.0.0 h1:K317FqzuhWc8YvSVlFMCCUb36O/S9MCKRDI7QkRKD/E=
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github.com/jinzhu/inflection v1.0.0/go.mod h1:h+uFLlag+Qp1Va5pdKtLDYj+kHp5pxUVkryuEj+Srlc=
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github.com/jinzhu/now v1.1.1 h1:g39TucaRWyV3dwDO++eEc6qf8TVIQ/Da48WmqjZ3i7E=
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10
main.go
10
main.go
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@ -179,6 +179,16 @@ func main() {
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}
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filters = append(filters, excludeFilter)
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}
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if len(config.PriceRanges) > 0 {
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converter := NewCurrencyConverter()
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for _, pr := range config.PriceRanges {
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rangeFilter, err := NewRangeFilter(pr.Model, pr.Min, pr.Max, pr.Currency, converter)
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if err != nil {
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log.Fatalf("cannot create price range filter: %s", err)
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}
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filters = append(filters, rangeFilter)
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}
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}
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// create parsers
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parsers := []Parser{}
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Reference in a new issue