What causes "login err: %w, data: %s" in AlistGo/alist?

Inspect the logged body (use debug level) to identify the new challenge format

login err: %w, data: %s

Error message

login err: %w, data: %s

What it means

During LanZou account login (mlogin.php), the response matched the acw_sc__v2 challenge pattern but CalcAcwScV2 failed to extract/derive the cookie value, so login aborts with both the parse error and the raw body. The account-mode driver cannot obtain session cookies until the challenge is solved.

Source

Thrown at drivers/lanzou/util.go:181

			"setSig":       "",
			"setScene":     "",
			"setTocen":     "",
			"formhash":     "",
		})
		if d.UserAgent != "" {
			req.SetHeader("User-Agent", d.UserAgent)
		}
		if acwScV2 != "" {
			req.SetCookie(&http.Cookie{Name: "acw_sc__v2", Value: acwScV2})
		}
		resp, err = req.Post(loginURL)
		if err != nil {
			return nil, err
		}
		if findAcwScV2Reg.Match(resp.Body()) {
			vs, e := CalcAcwScV2(resp.String())
			if e != nil {
				return nil, fmt.Errorf("login err: %w, data: %s", e, resp.Body())
			}
			acwScV2 = vs
			continue
		}
		break
	}
	if utils.Json.Get(resp.Body(), "zt").ToInt() != 1 {
		return nil, fmt.Errorf("login err: %s", resp.Body())
	}
	d.Cookie = CookieToString(resp.Cookies())
	return resp.Cookies(), nil
}

/*
通过cookie获取数据
*/

// 获取文件和文件夹,获取到的文件大小、更改时间不可信

View on GitHub (pinned to 843d9dc814)

Solutions

Inspect the logged body (use debug level) to identify the new challenge format
Wait several minutes and retry login — stricter challenges are often temporary after burst attempts
Update OpenList to get the current CalcAcwScV2 implementation; if maintaining a fork, widen the arg1 regex and verify the XOR key

Defensive patterns

Strategy: retry

Type guard

func isChallengeParseFailure(err error) bool {
    return err != nil && strings.Contains(err.Error(), "login err:") && strings.Contains(err.Error(), "acw")
}

Try / catch

cookies, err := d.Login()
if err != nil && isChallengeParseFailure(err) {
    // back off: stricter WAF challenge after burst attempts
    time.Sleep(10 * time.Minute)
    cookies, err = d.Login()
}

Prevention

Avoid tight login retry loops — they escalate the challenge strictness
Persist cookies (d.Cookie) so logins are rare rather than per-request
Keep the CalcAcwScV2 solver current via driver updates

When it happens

Trigger: Login POST returns a WAF challenge page whose arg1 payload does not match the extraction regex (format change/escaped HTML), making FindStringSubmatch fail inside CalcAcwScV2.

Common situations: WAF frontend updated with a new challenge variant; login attempts too frequent triggering a stricter challenge; CDN/regional differences serving incompatible challenge pages; body contains the marker string only incidentally (e.g. inside the debug log text).

Related errors

AI-assisted analysis of AlistGo/alist@843d9dc814 (2026-08-15). Data as JSON: /api/errors/c5257b53e335f69c. Report an issue: GitHub.