{
  "id": "python/starlette-cors-headers-missing",
  "signature": "RuntimeError: CORS headers missing for preflight request",
  "signature_zh": "运行时错误：预检请求缺少CORS头部",
  "regex": "RuntimeError:\\ CORS\\ headers\\ missing\\ for\\ preflight\\ request",
  "domain": "python",
  "category": "network_error",
  "subcategory": null,
  "root_cause": "Starlette应用未配置CORS中间件，导致跨域请求被拒绝",
  "root_cause_type": "generic",
  "root_cause_zh": "Starlette应用未配置CORS中间件，导致跨域请求被拒绝",
  "versions": [
    {
      "version": "3.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "在响应中手动添加Access-Control-Allow-Origin头",
      "why_fails": "预检请求（OPTIONS）需要特殊处理，手动添加可能遗漏",
      "fail_rate": 0.6,
      "condition": "",
      "sources": []
    },
    {
      "action": "使用Flask-CORS但项目是Starlette",
      "why_fails": "Flask-CORS不兼容Starlette",
      "fail_rate": 0.5,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "添加CORSMiddleware到应用",
      "success_rate": 0.95,
      "how": "from starlette.middleware.cors import CORSMiddleware\napp.add_middleware(CORSMiddleware, allow_origins=['*'])",
      "condition": "",
      "sources": []
    },
    {
      "action": "配置允许的特定域名",
      "success_rate": 0.9,
      "how": "app.add_middleware(CORSMiddleware, allow_origins=['https://example.com'])",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": null,
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.85,
  "fix_success_rate": 0.8,
  "resolvable": "true",
  "first_seen": "2024-10-02",
  "last_confirmed": "2025-01-01",
  "last_updated": "2025-01-01",
  "evidence_count": 0,
  "tags": [],
  "locale": "en",
  "aliases": []
}