feat: initial goget release — modern IPv6-first download utility

internal/auth/netrc.go

@@ -0,0 +1,103 @@
+//go:build linux || freebsd
+// +build linux freebsd
+
+package auth
+
+import (
+	"bufio"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// NetrcEntry holds credentials for a single machine entry in .netrc.
+type NetrcEntry struct {
+	Machine  string
+	Login    string
+	Password string
+}
+
+// LoadNetrc reads ~/.netrc and returns entries keyed by machine name.
+func LoadNetrc() (map[string]*NetrcEntry, error) {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return nil, nil
+	}
+	path := filepath.Join(home, ".netrc")
+	file, err := os.Open(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	defer file.Close()
+
+	entries := make(map[string]*NetrcEntry)
+	var current *NetrcEntry
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		// Skip comments and empty lines
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		fields := strings.Fields(line)
+
+		// "default" is also valid but we treat it as a machine
+		if len(fields) >= 2 && (fields[0] == "machine" || fields[0] == "default") {
+			if current != nil && current.Machine != "" {
+				entries[current.Machine] = current
+			}
+			name := fields[1]
+			if fields[0] == "default" {
+				name = "default"
+			}
+			current = &NetrcEntry{Machine: name}
+			// Rest of line may have login/password
+			parseNetrcLine(fields[2:], current)
+		} else if current != nil {
+			parseNetrcLine(fields, current)
+		}
+	}
+	if current != nil && current.Machine != "" {
+		entries[current.Machine] = current
+	}
+
+	return entries, scanner.Err()
+}
+
+func parseNetrcLine(fields []string, entry *NetrcEntry) {
+	for i := 0; i < len(fields); i++ {
+		switch fields[i] {
+		case "login":
+			if i+1 < len(fields) {
+				entry.Login = fields[i+1]
+				i++
+			}
+		case "password":
+			if i+1 < len(fields) {
+				entry.Password = fields[i+1]
+				i++
+			}
+		}
+	}
+}
+
+// LookupNetrc returns credentials from .netrc for a given hostname.
+func LookupNetrc(host string) (login, password string, found bool) {
+	entries, err := LoadNetrc()
+	if err != nil || entries == nil {
+		return "", "", false
+	}
+	// Exact match first
+	if e, ok := entries[host]; ok {
+		return e.Login, e.Password, true
+	}
+	// Default entry
+	if e, ok := entries["default"]; ok {
+		return e.Login, e.Password, true
+	}
+	return "", "", false
+}