init

internal/backend/exec.go

@@ -0,0 +1,109 @@
+package backend
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"os/exec"
+	"strings"
+	"time"
+)
+
+const DefaultTimeout = 15 * time.Second
+
+var BinaryName = "protonvpn"
+
+var ErrTimeout = errors.New("protonvpn: command timeout")
+
+var ErrNotFound = errors.New("protonvpn: binary not found in PATH")
+
+type Result struct {
+	Stdout string
+	Stderr string
+}
+
+type CommandError struct {
+	Result *Result
+	Err    error
+}
+
+const unexpectedErrorBanner = "An unexpected error occurred. Please try again."
+
+func (e *CommandError) Error() string {
+	if strings.HasPrefix(e.Result.Stderr, unexpectedErrorBanner) ||
+		strings.HasPrefix(e.Result.Stdout, unexpectedErrorBanner) {
+		return unexpectedErrorBanner
+	}
+	if e.Result.Stderr != "" {
+		return fmt.Sprintf("%v (stderr: %q)", e.Err, e.Result.Stderr)
+	}
+	if e.Result.Stdout != "" {
+		return e.Result.Stdout
+	}
+	return e.Err.Error()
+}
+
+func (e *CommandError) Unwrap() error {
+	return e.Err
+}
+
+func IsAuthRequired(err error) bool {
+	var cmdErr *CommandError
+	if !errors.As(err, &cmdErr) {
+		return false
+	}
+	return strings.Contains(cmdErr.Result.Stderr, "protonvpn signin") ||
+		strings.Contains(cmdErr.Result.Stdout, "protonvpn signin")
+}
+
+func IsFreePlanRestricted(err error) bool {
+	var cmdErr *CommandError
+	if !errors.As(err, &cmdErr) {
+		return false
+	}
+	return strings.Contains(cmdErr.Result.Stderr, "not available on the free plan") ||
+		strings.Contains(cmdErr.Result.Stdout, "not available on the free plan")
+}
+
+func Available() error {
+	if _, err := exec.LookPath(BinaryName); err != nil {
+		return ErrNotFound
+	}
+	return nil
+}
+
+func Run(ctx context.Context, args ...string) (*Result, error) {
+	if ctx == nil {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(context.Background(), DefaultTimeout)
+		defer cancel()
+	}
+
+	cmd := exec.CommandContext(ctx, BinaryName, args...)
+
+	var stdout, stderr bytes.Buffer
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+
+	runErr := cmd.Run()
+
+	res := &Result{
+		Stdout: strings.TrimSpace(stdout.String()),
+		Stderr: strings.TrimSpace(stderr.String()),
+	}
+
+	if ctx.Err() == context.DeadlineExceeded {
+		return res, &CommandError{Result: res, Err: ErrTimeout}
+	}
+
+	if runErr != nil {
+		return res, &CommandError{Result: res, Err: runErr}
+	}
+
+	if strings.HasPrefix(res.Stdout, "Error:") {
+		return res, &CommandError{Result: res, Err: errors.New(res.Stdout)}
+	}
+
+	return res, nil
+}