initial code

internal/provider/ovpn/updater/api.go

@@ -0,0 +1,185 @@
+package updater
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/netip"
+	"strings"
+
+	"github.com/qdm12/gluetun/internal/provider/common"
+)
+
+type apiData struct {
+	Success     bool            `json:"success"`
+	DataCenters []apiDataCenter `json:"datacenters"`
+}
+
+type apiDataCenter struct {
+	City        string      `json:"city"`
+	CountryName string      `json:"country_name"`
+	Servers     []apiServer `json:"servers"`
+}
+
+type apiServer struct {
+	IP                    netip.Addr `json:"ip"`
+	Ptr                   string     `json:"ptr"` // hostname
+	Online                bool       `json:"online"`
+	PublicKey             string     `json:"public_key"`
+	WireguardPorts        []uint16   `json:"wireguard_ports"`
+	MultiHopOpenvpnPort   uint16     `json:"multihop_openvpn_port"`
+	MultiHopWireguardPort uint16     `json:"multihop_wireguard_port"`
+}
+
+func fetchAPI(ctx context.Context, client *http.Client) (
+	data apiData, err error,
+) {
+	const url = "https://www.ovpn.com/v2/api/client/entry"
+
+	request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return data, err
+	}
+
+	response, err := client.Do(request)
+	if err != nil {
+		return data, err
+	}
+
+	if response.StatusCode != http.StatusOK {
+		_ = response.Body.Close()
+		return data, fmt.Errorf("%w: %d %s", common.ErrHTTPStatusCodeNotOK,
+			response.StatusCode, response.Status)
+	}
+
+	decoder := json.NewDecoder(response.Body)
+	err = decoder.Decode(&data)
+	if err != nil {
+		_ = response.Body.Close()
+		return data, fmt.Errorf("decoding response body: %w", err)
+	}
+
+	err = response.Body.Close()
+	if err != nil {
+		return data, fmt.Errorf("closing response body: %w", err)
+	}
+
+	return data, nil
+}
+
+var (
+	ErrCityNotSet        = errors.New("city is not set")
+	ErrCountryNameNotSet = errors.New("country name is not set")
+	ErrServersNotSet     = errors.New("servers array is not set")
+)
+
+func (a *apiDataCenter) validate() (err error) {
+	conditionalErrors := []conditionalError{
+		{err: ErrCityNotSet, condition: a.City == ""},
+		{err: ErrCountryNameNotSet, condition: a.CountryName == ""},
+		{err: ErrServersNotSet, condition: len(a.Servers) == 0},
+	}
+	err = collectErrors(conditionalErrors)
+	if err != nil {
+		var dataCenterSetFields []string
+		if a.CountryName != "" {
+			dataCenterSetFields = append(dataCenterSetFields, a.CountryName)
+		}
+		if a.City != "" {
+			dataCenterSetFields = append(dataCenterSetFields, a.City)
+		}
+		if len(dataCenterSetFields) == 0 {
+			return err
+		}
+		return fmt.Errorf("data center %s: %w",
+			strings.Join(dataCenterSetFields, ", "), err)
+	}
+
+	for i, server := range a.Servers {
+		err = server.validate()
+		if err != nil {
+			return fmt.Errorf("datacenter %s, %s: server %d of %d: %w",
+				a.CountryName, a.City, i+1, len(a.Servers), err)
+		}
+	}
+
+	return nil
+}
+
+var (
+	ErrIPFieldNotValid             = errors.New("ip address is not set")
+	ErrHostnameFieldNotSet         = errors.New("hostname field is not set")
+	ErrPublicKeyFieldNotSet        = errors.New("public key field is not set")
+	ErrWireguardPortsNotSet        = errors.New("wireguard ports array is not set")
+	ErrWireguardPortNotDefault     = errors.New("wireguard port is not the default 9929")
+	ErrMultiHopOpenVPNPortNotSet   = errors.New("multihop OpenVPN port is not set")
+	ErrMultiHopWireguardPortNotSet = errors.New("multihop WireGuard port is not set")
+)
+
+func (a *apiServer) validate() (err error) {
+	const defaultWireguardPort = 9929
+	conditionalErrors := []conditionalError{
+		{err: ErrIPFieldNotValid, condition: !a.IP.IsValid()},
+		{err: ErrHostnameFieldNotSet, condition: a.Ptr == ""},
+		{err: ErrPublicKeyFieldNotSet, condition: a.PublicKey == ""},
+		{err: ErrWireguardPortsNotSet, condition: len(a.WireguardPorts) == 0},
+		{
+			err:       ErrWireguardPortNotDefault,
+			condition: len(a.WireguardPorts) != 1 || a.WireguardPorts[0] != defaultWireguardPort,
+		},
+		{err: ErrMultiHopOpenVPNPortNotSet, condition: a.MultiHopOpenvpnPort == 0},
+		{err: ErrMultiHopWireguardPortNotSet, condition: a.MultiHopWireguardPort == 0},
+	}
+	err = collectErrors(conditionalErrors)
+	switch {
+	case err == nil:
+		return nil
+	case a.Ptr != "":
+		return fmt.Errorf("server %s: %w", a.Ptr, err)
+	case a.IP.IsValid():
+		return fmt.Errorf("server %s: %w", a.IP.String(), err)
+	default:
+		return err
+	}
+}
+
+type conditionalError struct {
+	err       error
+	condition bool
+}
+
+type joinedError struct {
+	errs []error
+}
+
+func (e *joinedError) Unwrap() []error {
+	return e.errs
+}
+
+func (e *joinedError) Error() string {
+	errStrings := make([]string, len(e.errs))
+	for i, err := range e.errs {
+		errStrings[i] = err.Error()
+	}
+	return strings.Join(errStrings, "; ")
+}
+
+func collectErrors(conditionalErrors []conditionalError) (err error) {
+	errs := make([]error, 0, len(conditionalErrors))
+	for _, conditionalError := range conditionalErrors {
+		if !conditionalError.condition {
+			continue
+		}
+		errs = append(errs, conditionalError.err)
+	}
+
+	if len(errs) == 0 {
+		return nil
+	}
+
+	return &joinedError{
+		errs: errs,
+	}
+}