platform: modularize api/gui, add docs-tests-web foundation, and refresh root config

selective-vpn-api/app/resolver/dns_config.go

@@ -0,0 +1,150 @@
+package resolver
+
+import (
+	"os"
+	"strings"
+)
+
+type DNSConfig struct {
+	Default  []string
+	Meta     []string
+	SmartDNS string
+	Mode     string
+}
+
+type DNSConfigDeps struct {
+	ActivePool               []string
+	IsSmartDNSForced         bool
+	SmartDNSAddr             string
+	SmartDNSForcedMode       string
+	ResolveFallbackPool      func() []string
+	MergeDNSUpstreamPools    func(primary, fallback []string) []string
+	NormalizeDNSUpstream     func(raw string, defaultPort string) string
+	NormalizeSmartDNSAddr    func(raw string) string
+	NormalizeDNSResolverMode func(raw string) string
+}
+
+func LoadDNSConfig(path string, base DNSConfig, deps DNSConfigDeps, logf func(string, ...any)) DNSConfig {
+	cfg := DNSConfig{
+		Default:  append([]string(nil), base.Default...),
+		Meta:     append([]string(nil), base.Meta...),
+		SmartDNS: strings.TrimSpace(base.SmartDNS),
+		Mode:     strings.TrimSpace(base.Mode),
+	}
+	if cfg.Mode == "" {
+		cfg.Mode = "direct"
+	}
+	if len(deps.ActivePool) > 0 {
+		cfg.Default = append([]string(nil), deps.ActivePool...)
+		cfg.Meta = append([]string(nil), deps.ActivePool...)
+	}
+
+	if deps.IsSmartDNSForced {
+		addr := strings.TrimSpace(deps.SmartDNSAddr)
+		if deps.NormalizeSmartDNSAddr != nil {
+			if n := deps.NormalizeSmartDNSAddr(addr); n != "" {
+				addr = n
+			}
+		}
+		if addr == "" {
+			addr = cfg.SmartDNS
+		}
+		cfg.Default = []string{addr}
+		cfg.Meta = []string{addr}
+		cfg.SmartDNS = addr
+		if strings.TrimSpace(deps.SmartDNSForcedMode) != "" {
+			cfg.Mode = deps.SmartDNSForcedMode
+		} else {
+			cfg.Mode = "smartdns"
+		}
+		if logf != nil {
+			logf("dns-config: SmartDNS forced (%s), ignore %s", addr, path)
+		}
+		return cfg
+	}
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		if logf != nil {
+			logf("dns-config: can't read %s: %v", path, err)
+		}
+		fallback := []string(nil)
+		if deps.ResolveFallbackPool != nil {
+			fallback = deps.ResolveFallbackPool()
+		}
+		if deps.MergeDNSUpstreamPools != nil {
+			cfg.Default = deps.MergeDNSUpstreamPools(cfg.Default, fallback)
+			cfg.Meta = deps.MergeDNSUpstreamPools(cfg.Meta, fallback)
+		}
+		return cfg
+	}
+
+	var def, meta []string
+	lines := strings.Split(string(data), "\n")
+	for _, ln := range lines {
+		s := strings.TrimSpace(ln)
+		if s == "" || strings.HasPrefix(s, "#") {
+			continue
+		}
+		parts := strings.Fields(s)
+		if len(parts) < 2 {
+			continue
+		}
+		key := strings.ToLower(parts[0])
+		vals := parts[1:]
+		switch key {
+		case "default":
+			for _, v := range vals {
+				if deps.NormalizeDNSUpstream != nil {
+					if n := deps.NormalizeDNSUpstream(v, "53"); n != "" {
+						def = append(def, n)
+					}
+				}
+			}
+		case "meta":
+			for _, v := range vals {
+				if deps.NormalizeDNSUpstream != nil {
+					if n := deps.NormalizeDNSUpstream(v, "53"); n != "" {
+						meta = append(meta, n)
+					}
+				}
+			}
+		case "smartdns":
+			if len(vals) > 0 && deps.NormalizeSmartDNSAddr != nil {
+				if n := deps.NormalizeSmartDNSAddr(vals[0]); n != "" {
+					cfg.SmartDNS = n
+				}
+			}
+		case "mode":
+			if len(vals) > 0 {
+				rawMode := vals[0]
+				if deps.NormalizeDNSResolverMode != nil {
+					cfg.Mode = deps.NormalizeDNSResolverMode(rawMode)
+				} else {
+					cfg.Mode = strings.ToLower(strings.TrimSpace(rawMode))
+				}
+			}
+		}
+	}
+	if len(deps.ActivePool) == 0 {
+		if len(def) > 0 {
+			cfg.Default = def
+		}
+		if len(meta) > 0 {
+			cfg.Meta = meta
+		}
+	}
+
+	fallback := []string(nil)
+	if deps.ResolveFallbackPool != nil {
+		fallback = deps.ResolveFallbackPool()
+	}
+	if deps.MergeDNSUpstreamPools != nil {
+		cfg.Default = deps.MergeDNSUpstreamPools(cfg.Default, fallback)
+		cfg.Meta = deps.MergeDNSUpstreamPools(cfg.Meta, fallback)
+	}
+	if logf != nil {
+		logf("dns-config: accept %s: mode=%s smartdns=%s default=%v; meta=%v", path, cfg.Mode, cfg.SmartDNS, cfg.Default, cfg.Meta)
+	}
+	return cfg
+}