geektutu/7days-golang · warning

bad request

Error message

bad request

What it means

HTTP 400 response in HTTPPool.ServeHTTP: the URL path after basePath does not split into exactly two parts "<groupname>/<key>", meaning the request path is malformed for the peer protocol. It fires on requests missing the key segment or containing extra slashes.

Source

Thrown at gee-cache/day5-multi-nodes/geecache/http.go:51

		basePath: defaultBasePath,
	}
}

// Log info with server name
func (p *HTTPPool) Log(format string, v ...interface{}) {
	log.Printf("[Server %s] %s", p.self, fmt.Sprintf(format, v...))
}

// ServeHTTP handle all http requests
func (p *HTTPPool) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if !strings.HasPrefix(r.URL.Path, p.basePath) {
		panic("HTTPPool serving unexpected path: " + r.URL.Path)
	}
	p.Log("%s %s", r.Method, r.URL.Path)
	// /<basepath>/<groupname>/<key> required
	parts := strings.SplitN(r.URL.Path[len(p.basePath):], "/", 2)
	if len(parts) != 2 {
		http.Error(w, "bad request", http.StatusBadRequest)
		return
	}

	groupName := parts[0]
	key := parts[1]

	group := GetGroup(groupName)
	if group == nil {
		http.Error(w, "no such group: "+groupName, http.StatusNotFound)
		return
	}

	view, err := group.Get(key)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

View on GitHub (pinned to cf36443821)

Solutions

1. Request the full /<basePath>/<group>/<key> URL.
2. Use a dedicated health endpoint instead of the geecache pool for probes.
3. Audit proxy/ingress rewrite rules.
4. Encode '/' inside keys so SplitN produces exactly two parts.

Example fix

// before
GET /_geecache/users
// after
GET /_geecache/users/42

// day5: enforce URL shape client-side
func buildCacheURL(base, group, key string) (string, error) {
    if group == "" || key == "" || strings.Contains(key, "/") {
        return "", fmt.Errorf("invalid cache path: group=%q key=%q", group, key)
    }
    return base + "/" + group + "/" + url.PathEscape(key), nil
}

When it happens

Trigger: Requests like GET /_geecache/ or GET /_geecache/group without a key segment.

Common situations: Health probes against the cache route; clients forgetting the key; proxies stripping part of the URL; ad-hoc curl testing with incomplete paths.

Related errors

• bad request
• bad request
• key is required
• no such group: "+groupName
• err.Error()

AI-assisted analysis of geektutu/7days-golang@cf36443821 (2026-09-03). Data as JSON: /api/errors/655590e0667f01c3. Report an issue: GitHub.