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fix(backend): API 文本输入加 max_length + 请求体大小中间件（CR-H9）

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This commit is contained in:
Yaojia Wang
2026-07-08 10:53:44 +02:00
parent 26f10d023d
commit e1a24a2c2c
13 changed files with 223 additions and 30 deletions
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109
apps/api/tests/test_input_size_limits.py Normal file
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@@ -0,0 +1,109 @@
"""CR-H9：用户请求文本字段 max_length 上界 + 应用级请求体大小中间件（防 DoS/成本）。
- 单元：各请求 schema 的字符串字段在 cap 处可构造、cap+1 触发 ValidationError（含样本列表长度
与列表项两处上界——最大 DoS 面）。
- 集成（无 pg）：超大请求体经中间件直接 413（不入路由/DB）。
"""
from __future__ import annotations
import os
from dataclasses import dataclass, field
from typing import Any
import pytest
from cryptography.fernet import Fernet
from pydantic import BaseModel, ValidationError
# create_app() 于 import ww_api.main 时构建，需 CREDENTIAL_ENC_KEY——先于任何 main 导入置好。
os.environ.setdefault("CREDENTIAL_ENC_KEY", Fernet.generate_key().decode())
from ww_api.schemas.foreshadow import ForeshadowRegisterRequest
from ww_api.schemas.generation import CharacterGenerateRequest, WorldGenerateRequest
from ww_api.schemas.projects import (
AcceptRequest,
DraftSaveRequest,
ProjectCreateRequest,
ReviewRequest,
)
from ww_api.schemas.providers import (
ProviderCredentialInput,
TierRoutingInput,
)
from ww_api.schemas.providers import (
TestConnectionRequest as _TestConnectionRequest, # 别名避免 pytest 误采集 Test* 类
)
from ww_api.schemas.rules import RuleCreateRequest
from ww_api.schemas.style import RefineRequest, StyleLearnRequest
from ww_api.schemas.templates import TemplateCreateRequest
@dataclass(frozen=True)
class _StrCase:
"""一个字符串字段的上界用例：cap 处可构造、cap+1 触发 ValidationError。"""
schema: type[BaseModel]
field_name: str
cap: int
case_id: str
base: dict[str, Any] = field(default_factory=dict) # 该 schema 其余必填字段
_STR_CASES: list[_StrCase] = [
_StrCase(ProviderCredentialInput, "api_key", 512, "api_key<=512", {"provider": "p"}),
_StrCase(ProviderCredentialInput, "provider", 64, "provider<=64", {"api_key": "k"}),
_StrCase(TierRoutingInput, "model", 128, "model<=128", {"tier": "writer", "provider": "p"}),
_StrCase(
TierRoutingInput, "provider", 64, "routing-provider<=64", {"tier": "writer", "model": "m"}
),
_StrCase(_TestConnectionRequest, "provider", 64, "test-provider<=64"),
_StrCase(WorldGenerateRequest, "brief", 10_000, "world-brief<=10000"),
_StrCase(CharacterGenerateRequest, "brief", 10_000, "char-brief<=10000"),
_StrCase(ProjectCreateRequest, "title", 200, "title<=200"),
_StrCase(AcceptRequest, "final_text", 200_000, "final_text<=200000"),
_StrCase(DraftSaveRequest, "text", 200_000, "draft-text<=200000"),
_StrCase(ReviewRequest, "draft", 200_000, "review-draft<=200000"),
_StrCase(RefineRequest, "segment", 20_000, "segment<=20000"),
_StrCase(ForeshadowRegisterRequest, "code", 100, "code<=100", {"title": "t"}),
_StrCase(ForeshadowRegisterRequest, "title", 500, "foreshadow-title<=500", {"code": "c"}),
_StrCase(RuleCreateRequest, "content", 10_000, "rule-content<=10000", {"level": "project"}),
_StrCase(TemplateCreateRequest, "title", 200, "template-title<=200", {"body": "b"}),
_StrCase(TemplateCreateRequest, "body", 20_000, "template-body<=20000", {"title": "t"}),
]
@pytest.mark.parametrize("case", _STR_CASES, ids=[c.case_id for c in _STR_CASES])
def test_request_str_fields_reject_over_max_length(case: _StrCase) -> None:
# Arrange / Act — 长度 == cap：构造成功。
case.schema(**{**case.base, case.field_name: "x" * case.cap})
# Assert — 长度 == cap+1：超界即 ValidationError。
with pytest.raises(ValidationError):
case.schema(**{**case.base, case.field_name: "x" * (case.cap + 1)})
def test_style_learn_samples_item_and_list_caps() -> None:
# 单条样本 == 20_000 字符 OK；20_001 → ValidationError（最大 DoS 面：每条正文都设上界）。
StyleLearnRequest(samples=["x" * 20_000])
with pytest.raises(ValidationError):
StyleLearnRequest(samples=["x" * 20_001])
# 列表 == 20 条 OK；21 条 → ValidationError（同时约束列表长度）。
StyleLearnRequest(samples=["s"] * 20)
with pytest.raises(ValidationError):
StyleLearnRequest(samples=["s"] * 21)
def test_oversized_request_body_rejected_413() -> None:
"""超大请求体经 body-size 中间件直接 413（不入路由/DB）。
不以 context manager 进入 TestClient → 不跑 lifespan/seed → 不需 Postgres。中间件在
路由前拦截，故请求根本不触达任何 DB。
"""
from fastapi.testclient import TestClient
from ww_api.main import create_app
from ww_api.middleware import MAX_BODY_BYTES
client = TestClient(create_app())
resp = client.post("/projects", content=b"x" * (MAX_BODY_BYTES + 1))
assert resp.status_code == 413
assert resp.json()["error"]["code"] == "PAYLOAD_TOO_LARGE"

8
apps/api/ww_api/main.py
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@@ -14,7 +14,11 @@ from ww_db import get_sessionmaker
from ww_shared import AppError, ErrorBody, ErrorCode, ErrorEnvelope
from ww_api.logging_config import configure_logging, get_logger
from ww_api.middleware import REQUEST_ID_HEADER, request_id_middleware
from ww_api.middleware import (
REQUEST_ID_HEADER,
body_size_limit_middleware,
request_id_middleware,
)
from ww_api.routers import (
chain,
foreshadow,
@@ -74,6 +78,8 @@ def create_app() -> FastAPI:
allow_headers=["content-type", "authorization", REQUEST_ID_HEADER],
)
app.middleware("http")(request_id_middleware)
# 请求体大小守卫（CR-H9）：在路由前拦截超大 body，直接 413。
app.middleware("http")(body_size_limit_middleware)
@app.exception_handler(AppError)
async def _app_error_handler(request: Request, exc: AppError) -> JSONResponse:

32
apps/api/ww_api/middleware.py
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@@ -12,10 +12,14 @@ from collections.abc import Awaitable, Callable
import structlog
from starlette.requests import Request
from starlette.responses import Response
from starlette.responses import JSONResponse, Response
from ww_shared import ErrorBody, ErrorCode, ErrorEnvelope
REQUEST_ID_HEADER = "x-request-id"
# 请求体大小上限（2 MiB）：超过即 413，防超大 body 撑爆内存/成本（CR-H9）。
MAX_BODY_BYTES = 2 * 1024 * 1024
# 放行安全字符集（字母数字 . _ -，1–128 位）：覆盖 uuid4().hex、常见 trace id 与客户端
# 自定义短 id；含空白/控制字符/换行/注入序列/超长的一律丢弃改生成新 uuid——防止把未经
# 校验的客户端值原样写进日志/响应头（日志注入防护）。
@@ -38,3 +42,29 @@ async def request_id_middleware(
response = await call_next(request)
response.headers[REQUEST_ID_HEADER] = request_id
return response
async def body_size_limit_middleware(
request: Request, call_next: Callable[[Request], Awaitable[Response]]
) -> Response:
"""按 `Content-Length` 拦截超大请求体，超限直接 413（CR-H9）。
用户中间件跑在 FastAPI 的 AppError 处理器**之外**，故必须自建错误信封响应（不能靠抛
AppError）。分块编码（无 `Content-Length`）无法在此拦截——单用户原型可接受的限制。
"""
content_length = request.headers.get("content-length")
if content_length is not None:
try:
size = int(content_length)
except ValueError:
size = 0 # 非法头防御性视作 0，交由下游正常解析/报错。
if size > MAX_BODY_BYTES:
envelope = ErrorEnvelope(
error=ErrorBody(
code=ErrorCode.PAYLOAD_TOO_LARGE,
message="请求体过大",
request_id=_sanitize_request_id(request.headers.get(REQUEST_ID_HEADER)),
)
)
return JSONResponse(status_code=413, content=envelope.model_dump())
return await call_next(request)

10
apps/api/ww_api/schemas/foreshadow.py
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@@ -11,12 +11,18 @@ from typing import Any
from pydantic import BaseModel, Field
# 请求字符串字段长度上界（CR-H9：防超长入参 DoS/成本）。代号=短标识；标题=一句话。
_CODE_MAX = 100
_TITLE_MAX = 500
class ForeshadowRegisterRequest(BaseModel):
"""POST /projects/:id/foreshadow：作者显式登记一条伏笔（status 落 OPEN）。"""
code: str = Field(min_length=1, description="伏笔代号，`(project_id, code)` 唯一")
title: str = Field(min_length=1, description="伏笔标题/一句话描述")
code: str = Field(
min_length=1, max_length=_CODE_MAX, description="伏笔代号，`(project_id, code)` 唯一"
)
title: str = Field(min_length=1, max_length=_TITLE_MAX, description="伏笔标题/一句话描述")
planted_at: int | None = Field(default=None, description="埋设章号")
content: str | None = Field(default=None, description="伏笔正文/线索")
expected_close_from: int | None = Field(default=None, description="预期回收窗口起始章")

9
apps/api/ww_api/schemas/generation.py
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@@ -19,6 +19,9 @@ from ww_api.schemas.rules import RuleView
# 批量生成数量上限（防一次性巨量调用；原型保守值）。
MAX_GENERATE_COUNT = 12
# 一句话需求文本上界（CR-H9：防超长入参撑爆上下文/成本）。
_BRIEF_MAX = 10_000
# ---- 世界观生成（预览）----
@@ -26,7 +29,9 @@ MAX_GENERATE_COUNT = 12
class WorldGenerateRequest(BaseModel):
"""POST /projects/:id/world/generate：据需求生成世界观实体（预览）。"""
brief: str = Field(min_length=1, description="世界观生成需求（题材/设定方向/约束）")
brief: str = Field(
min_length=1, max_length=_BRIEF_MAX, description="世界观生成需求（题材/设定方向/约束）"
)
class WorldEntityCardView(BaseModel):
@@ -54,7 +59,7 @@ class CharacterGenerateRequest(BaseModel):
单一 `role` + `count` 语义。
"""
brief: str = Field(min_length=1, description="角色生成需求")
brief: str = Field(min_length=1, max_length=_BRIEF_MAX, description="角色生成需求")
count: int = Field(
default=1,
ge=1,

18
apps/api/ww_api/schemas/projects.py
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@@ -11,11 +11,15 @@ from typing import Any, Literal
from pydantic import BaseModel, Field
# 请求文本长度上界（CR-H9：防超长入参 DoS/成本）。标题=标签级；章正文=整章级。
_TITLE_MAX = 200
_CHAPTER_TEXT_MAX = 200_000
class ProjectCreateRequest(BaseModel):
"""POST /projects：立项向导字段（owner_id 由后端补 stub，不入参）。"""
title: str = Field(min_length=1)
title: str = Field(min_length=1, max_length=_TITLE_MAX)
genre: str | None = None
logline: str | None = None
premise: str | None = None
@@ -120,9 +124,9 @@ class DraftStreamRequest(BaseModel):
directive: str | None = None
# 整章重写输入上界（守 DoS/成本，CR-H9 方向）：意见短、整章草稿大。
# 整章重写输入上界（守 DoS/成本，CR-H9 方向）：意见短、整章草稿大（复用章正文上界，DRY）。
_REWRITE_FEEDBACK_MAX = 4000
_REWRITE_DRAFT_MAX = 200_000
_REWRITE_DRAFT_MAX = _CHAPTER_TEXT_MAX
class RewriteStreamRequest(BaseModel):
@@ -140,7 +144,7 @@ class RewriteStreamRequest(BaseModel):
class DraftSaveRequest(BaseModel):
"""PUT /projects/:id/chapters/:no/draft：自动保存草稿正文。"""
text: str
text: str = Field(max_length=_CHAPTER_TEXT_MAX)
class DraftResponse(BaseModel):
@@ -179,7 +183,7 @@ class ReviewRequest(BaseModel):
不传 `draft` 时端点回退到已保存的草稿（chapter_repo）。
"""
draft: str | None = None
draft: str | None = Field(default=None, max_length=_CHAPTER_TEXT_MAX)
class ReviewConflictView(BaseModel):
@@ -237,7 +241,9 @@ class ConflictDecision(BaseModel):
class AcceptRequest(BaseModel):
"""POST /projects/:id/chapters/:no/accept：裁决清单 + 可能改过的终稿。"""
final_text: str = Field(min_length=1, description="作者裁决/改稿后的最终验收文本")
final_text: str = Field(
min_length=1, max_length=_CHAPTER_TEXT_MAX, description="作者裁决/改稿后的最终验收文本"
)
decisions: list[ConflictDecision] = Field(
default_factory=list, description="对最近审稿每个冲突的裁决（每冲突必有其一，R5）"
)

15
apps/api/ww_api/schemas/providers.py
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@@ -8,6 +8,11 @@ from __future__ import annotations
from pydantic import BaseModel, Field
from ww_llm_gateway.types import Tier
# 请求字符串字段长度上界（CR-H9：防超长入参 DoS/成本）。
_PROVIDER_MAX = 64
_MODEL_MAX = 128
_API_KEY_MAX = 512
class ProviderView(BaseModel):
"""已配置提供商（掩码视图）。"""
@@ -35,8 +40,8 @@ class ProvidersResponse(BaseModel):
class ProviderCredentialInput(BaseModel):
"""单条提供商凭据写入。"""
provider: str = Field(min_length=1)
api_key: str = Field(min_length=1) # 明文入站，加密入库，绝不回显
provider: str = Field(min_length=1, max_length=_PROVIDER_MAX)
api_key: str = Field(min_length=1, max_length=_API_KEY_MAX) # 明文入站，加密入库，绝不回显
class TierRoutingInput(BaseModel):
@@ -44,8 +49,8 @@ class TierRoutingInput(BaseModel):
# tier 限定已知档位 writer/analyst/light；未知档位 → 422（QA MEDIUM：原接受任意字符串）。
tier: Tier
provider: str = Field(min_length=1)
model: str = Field(min_length=1)
provider: str = Field(min_length=1, max_length=_PROVIDER_MAX)
model: str = Field(min_length=1, max_length=_MODEL_MAX)
fallback: list[str] = Field(default_factory=list)
@@ -59,7 +64,7 @@ class ProvidersUpsertRequest(BaseModel):
class TestConnectionRequest(BaseModel):
"""POST /test：最小探测请求。"""
provider: str = Field(min_length=1)
provider: str = Field(min_length=1, max_length=_PROVIDER_MAX)
class CapabilitiesView(BaseModel):

7
apps/api/ww_api/schemas/rules.py
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@@ -14,8 +14,13 @@ from pydantic import BaseModel, Field, StringConstraints
RuleLevel = Literal["global", "genre", "style", "project"]
# 规则正文长度上界（CR-H9：防超长入参 DoS/成本）。
_RULE_CONTENT_MAX = 10_000
# 先 strip 再校验长度：纯空白内容（" "）strip 后为空 → 422（QA MEDIUM：此前被接受入库）。
RuleContent = Annotated[str, StringConstraints(strip_whitespace=True, min_length=1)]
RuleContent = Annotated[
str, StringConstraints(strip_whitespace=True, min_length=1, max_length=_RULE_CONTENT_MAX)
]
class RuleCreateRequest(BaseModel):

24
apps/api/ww_api/schemas/style.py
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@@ -7,15 +7,26 @@ snake_case（命名契约，见 memory/gotchas）。前端经 OpenAPI→TS 客
from __future__ import annotations
import uuid
from typing import Literal
from typing import Annotated, Literal
from pydantic import BaseModel, Field
from pydantic import BaseModel, Field, StringConstraints
# 请求文本长度上界（CR-H9：防超长入参空跑 LLM/DoS）。选段/样本 20k 字符，样本列表 ≤20 条。
_SEGMENT_MAX = 20_000
_SAMPLE_MAX = 20_000
_SAMPLES_LIST_MAX = 20
# 预检澄清沿用相同选段上界（DRY）；指令短。
_MAX_CLARIFY_SEGMENT_LEN = _SEGMENT_MAX
_MAX_CLARIFY_INSTRUCTION_LEN = 2000
class StyleLearnRequest(BaseModel):
"""学文风：上传样本正文（前端可读文件转文本）+ 模式（首学 / 更新）。"""
samples: list[str] = Field(min_length=1)
# 同时约束**列表条数**与**每条样本长度**（最大 DoS 面：多条超长正文）。
samples: list[Annotated[str, StringConstraints(max_length=_SAMPLE_MAX)]] = Field(
min_length=1, max_length=_SAMPLES_LIST_MAX
)
mode: Literal["create", "update"] = "create"
@@ -47,7 +58,7 @@ class StyleFingerprintResponse(BaseModel):
class RefineRequest(BaseModel):
"""回炉：重写选中段（可选改写指令）。"""
segment: str = Field(min_length=1)
segment: str = Field(min_length=1, max_length=_SEGMENT_MAX)
instruction: str | None = None
@@ -58,11 +69,6 @@ class RefineResponse(BaseModel):
refined: str
# 上界：选段/意见文本长度守卫（防超长入参空跑 LLM；预检只看本段，无需整章）。
_MAX_CLARIFY_SEGMENT_LEN = 20000
_MAX_CLARIFY_INSTRUCTION_LEN = 2000
class RefineClarifyRequest(BaseModel):
"""润色预检澄清：选段 + 再沟通意见（WFW-9 M1 路线A 两阶段之「问题」阶段）。

15
apps/api/ww_api/schemas/templates.py
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@@ -12,15 +12,24 @@ from typing import Annotated
from pydantic import BaseModel, Field, StringConstraints
# 长度上界（CR-H9：防超长入参 DoS/成本）。标题=标签级；正文=段落级。
_TITLE_MAX = 200
_BODY_MAX = 20_000
# 先去首尾空白再校验长度：纯空白（" "）strip 后为空 → min_length=1 不满足 → 422。
NonBlankStr = Annotated[str, StringConstraints(strip_whitespace=True, min_length=1)]
NonBlankTitle = Annotated[
str, StringConstraints(strip_whitespace=True, min_length=1, max_length=_TITLE_MAX)
]
NonBlankBody = Annotated[
str, StringConstraints(strip_whitespace=True, min_length=1, max_length=_BODY_MAX)
]
class TemplateCreateRequest(BaseModel):
"""POST /templates：新建一条提示词模板。"""
title: NonBlankStr = Field(description="模板标题（非空，纯空白 → 422）")
body: NonBlankStr = Field(description="模板正文（非空，一键填入生成器的 brief/text）")
title: NonBlankTitle = Field(description="模板标题（非空，纯空白 → 422）")
body: NonBlankBody = Field(description="模板正文（非空，一键填入生成器的 brief/text）")
category: str | None = Field(default=None, description="可选分类")
tool_key: str | None = Field(default=None, description="可选关联生成器（NULL=通用）")