refactor: expose constructor from URL

pkg/database/database.go

@@ -3,6 +3,7 @@ package database
 
 import (
 	"encoding/csv"
+	"io"
 	"net"
 	"net/http"
 	"slices"
@@ -19,16 +20,6 @@ type Entry struct {
 	Data    []string
 }
 
-// fetchCsv fetches a CSV file from the given URL and returns its records.
-func fetchCsv(url string) ([][]string, error) {
-	resp, err := http.Get(url) // #nosec G107
-	if err != nil {
-		return nil, err
-	}
-	defer resp.Body.Close()
-	return csv.NewReader(resp.Body).ReadAll()
-}
-
 // sanatizeData trims the leading and trailing spaces from the given strings.
 func sanatizeData(data []string) []string {
 	sanitized := make([]string, len(data))
@@ -78,9 +69,9 @@ type Database struct {
 }
 
 // NewDatabase creates a new database from the given URL.
-func NewDatabase(url string) (*Database, error) {
+func NewDatabase(reader io.Reader) (*Database, error) {
 	// Records are the raw data from the CSV file.
-	records, err := fetchCsv(url)
+	records, err := csv.NewReader(reader).ReadAll()
 	if err != nil {
 		return nil, err
 	}
@@ -98,6 +89,16 @@ func NewDatabase(url string) (*Database, error) {
 	return &Database{entries: entries}, nil
 }
 
+// NewDatabaseURL creates a new database from the given URL.
+func NewDatabaseURL(url string) (*Database, error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	return NewDatabase(resp.Body)
+}
+
 // Find returns the data associated with the entry that contains the given IP.
 // If the IP is not found, nil is returned.
 func (db *Database) Find(ip net.IP) []string {

pkg/database/resolver.go

@@ -34,22 +34,22 @@ type Resolver struct {
 
 // NewResolver creates a new IP resolver.
 func NewResolver() (*Resolver, error) {
-	countryDBv4, err := NewDatabase(countryIPv4URL)
+	countryDBv4, err := NewDatabaseURL(countryIPv4URL)
 	if err != nil {
 		return nil, err
 	}
 
-	countryDBv6, err := NewDatabase(countryIPv6URL)
+	countryDBv6, err := NewDatabaseURL(countryIPv6URL)
 	if err != nil {
 		return nil, err
 	}
 
-	asnDBv4, err := NewDatabase(asnIPv4URL)
+	asnDBv4, err := NewDatabaseURL(asnIPv4URL)
 	if err != nil {
 		return nil, err
 	}
 
-	asnDBv6, err := NewDatabase(asnIPv6URL)
+	asnDBv6, err := NewDatabaseURL(asnIPv6URL)
 	if err != nil {
 		return nil, err
 	}