initial: novel-app snapshot

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omo
2026-08-17 17:11:30 +08:00
commit 1ae06209ac
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services/__init__.py Normal file
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"""Service layer for the novel app.
Pure functions — no Flask imports. LLM access, book deconstruction (拆书),
and chapter writing with context assembly. All DB access goes through
explicit sqlite3 connections (row_factory=sqlite3.Row) and repository
functions. SSE framing helpers live here for use by routes/.
"""

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services/chapter_writer.py Normal file
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"""Chapter generation service: context assembly + streaming chapter writing.
Pure functions — no Flask imports. Context assembly follows the 拆书→写书
pipeline: recent chapters full-text, earlier chapters as short summaries,
relevant characters, open foreshadowing, novel meta. Total prompt size is
bounded by ``config.CTX_BUDGET_MAX``.
"""
import json
import logging
import config
from repositories import chapter_repo, character_repo, foreshadowing_repo
from services import llm
logger = logging.getLogger(__name__)
SYSTEM_PROMPT = (
"你是一位专业网文写手, 擅长按大纲续写章节, 文风贴合用户指定风格。"
"只输出章节正文, 不要输出标题、解释或任何元信息。"
)
_EARLIER_SUMMARY_CHARS = 200 # per earlier-chapter heuristic summary
_PREFIX_TAIL_CHARS = 500 # how much of a resume-prefix to echo back
def _truncate(text, limit):
if not isinstance(text, str):
return text
if len(text) <= limit:
return text
return text[:limit] + "..."
def build_chapter_context(db, novel, chapter, ctx_prev=None):
"""Assemble the context dict for writing ``chapter`` of ``novel``.
Budget enforcement: drop earlier summaries first, then truncate prev
chapter contents, to stay under ``config.CTX_BUDGET_MAX``.
"""
novel_id = novel["id"]
prev_limit = ctx_prev or config.CTX_PREV_CHAPTERS
prev = chapter_repo.get_previous_chapters(
db, novel_id, chapter.get("volume") or 1,
chapter.get("chapter_number") or 1, limit=prev_limit,
)
prev_chapters = [
{"title": c.get("title"), "volume": c.get("volume"),
"chapter_number": c.get("chapter_number"), "content": c.get("content") or ""}
for c in reversed(prev) # chronological order
]
prev_ids = {c["id"] for c in prev}
done = chapter_repo.list_done_chapters(
db, novel_id, limit=config.CTX_SUMMARY_CHAPTERS
)
earlier_summaries = [
{"title": c.get("title"), "volume": c.get("volume"),
"chapter_number": c.get("chapter_number"),
"summary": _truncate(c.get("content") or "", _EARLIER_SUMMARY_CHARS)}
for c in done if c["id"] not in prev_ids
]
outline = chapter.get("outline") or ""
characters = character_repo.find_characters_in_text(db, novel_id, outline)
if not characters:
characters = character_repo.list_characters(db, novel_id)
context = {
"novel_meta": {
"title": novel.get("title"),
"genre": novel.get("genre"),
"style": novel.get("style"),
},
"prev_chapters": prev_chapters,
"earlier_summaries": earlier_summaries,
"characters": characters,
"open_foreshadowing": foreshadowing_repo.list_open_foreshadowing(db, novel_id),
}
serialized = json.dumps(context, ensure_ascii=False, default=str)
# Budget pass 1: drop earlier summaries.
if len(serialized) > config.CTX_BUDGET_MAX and context["earlier_summaries"]:
logger.info("chapter context over budget, dropping earlier summaries")
context["earlier_summaries"] = []
serialized = json.dumps(context, ensure_ascii=False, default=str)
# Budget pass 2: truncate prev chapter bodies proportionally.
if len(serialized) > config.CTX_BUDGET_MAX and context["prev_chapters"]:
per = max(1000, config.CTX_BUDGET_MAX // (2 * len(context["prev_chapters"])))
for c in context["prev_chapters"]:
c["content"] = _truncate(c["content"], per)
serialized = json.dumps(context, ensure_ascii=False, default=str)
logger.info("chapter context over budget, truncated prev chapters to %d chars each", per)
context["total_chars"] = len(serialized)
if len(serialized) < config.CTX_BUDGET_MIN:
logger.info(
"chapter context small (%d chars < %d): early chapter or sparse data",
len(serialized), config.CTX_BUDGET_MIN,
)
return context
def build_chapter_prompts(context, chapter, prefix=None):
"""Assemble system/user messages for chapter generation."""
meta = context["novel_meta"]
parts = [
f"小说: 《{meta['title']}》 类型: {meta['genre']} 文风: {meta['style']}",
"",
]
if context["earlier_summaries"]:
parts.append("【更早章节摘要】")
for s in context["earlier_summaries"]:
parts.append(
f"{s['volume']}卷 第{s['chapter_number']}{s.get('title') or ''}: {s['summary']}"
)
parts.append("")
if context["prev_chapters"]:
parts.append("【最近章节正文】")
for c in context["prev_chapters"]:
parts.append(
f"--- 第{c['volume']}卷 第{c['chapter_number']}{c.get('title') or ''} ---"
)
parts.append(c["content"])
parts.append("")
if context["characters"]:
parts.append("【相关角色】")
for ch in context["characters"]:
parts.append(
f"{ch.get('name')} ({ch.get('role') or '角色'}, 状态: {ch.get('status')}): "
f"{_truncate(ch.get('description') or '', 300)}"
)
parts.append("")
if context["open_foreshadowing"]:
parts.append("【未回收伏笔】")
for f in context["open_foreshadowing"]:
parts.append(f"- {f.get('description')} (埋设: 第{f.get('planted_chapter') or '?'}章)")
parts.append("")
parts.append("【当前章节大纲】")
parts.append(
f"{chapter.get('volume') or 1}卷 第{chapter.get('chapter_number') or 1}"
f"{chapter.get('title') or ''}"
)
parts.append(chapter.get("outline") or "(无大纲, 请自由发挥但承接前文)")
parts.append("")
if prefix:
parts.append("【续写指令】以下为本章已生成的开头, 请无缝续写, 不要重复已有内容:")
parts.append(prefix[-_PREFIX_TAIL_CHARS:])
parts.append("")
parts.append("要求: 写 3000-8000 字正文, 只输出正文, 不要标题不要解释。")
user_prompt = "\n".join(parts)
return [
{"role": "system", "content": SYSTEM_PROMPT},
{"role": "user", "content": user_prompt},
]
def stream_chapter(db, novel, chapter, prefix=None):
"""Generator yielding SSE frames: context → token… → done / error.
NOTE: ``db`` is only used here to build the context; callers must build
everything inside the request view and may pass a connection that dies
with the request — so we build context eagerly before streaming.
"""
context = build_chapter_context(db, novel, chapter)
summary = (
f"已注入上下文: 前 {len(context['prev_chapters'])} 章正文, "
f"{len(context['earlier_summaries'])} 条更早摘要, "
f"{len(context['characters'])} 个角色, "
f"{len(context['open_foreshadowing'])} 条未回收伏笔, "
f"共约 {context['total_chars']} 字符"
+ (f"; 续写前缀 {len(prefix)} 字符" if prefix else "")
)
yield llm._sse("context", {"summary": summary})
messages = build_chapter_prompts(context, chapter, prefix=prefix)
parts = []
def _on_token(t):
parts.append(t)
yield from llm.make_token_stream(messages, _on_token, max_tokens=8192)
full_text = (prefix or "") + "".join(parts)
yield llm._sse("done", {"content": full_text, "word_count": len(full_text)})

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"""Book deconstruction (拆书) service: novel architect that produces
concept, world, characters, outline, and foreshadowing sections.
Pure functions — no Flask imports. Each section is streamed via
:func:`llm.make_token_stream` with ``section_start`` / ``section_end``
SSE bookends.
"""
import logging
from services import llm
logger = logging.getLogger(__name__)
SECTIONS = ["concept", "world", "characters", "outline", "foreshadowing"]
SYSTEM_PROMPT = (
"你是一位资深小说架构师, 精通网文结构设计与节奏把控。"
"请根据用户的需求, 逐步构建完整的小说框架。"
"输出纯文本, 不要使用 Markdown 标题标记 (# / ## 等), 用换行分段即可。"
)
# ---- per-section Chinese user prompts -----------------------------------
_SECTION_PROMPTS = {
"concept": (
"请为小说《{title}》设计核心概念, 包括:\n"
"1. 主题 (这部小说想表达什么)\n"
"2. 核心冲突 (主角面临的主要矛盾)\n"
"3. 一句话卖点 (最能吸引读者的概括)\n"
"类型: {genre} | 风格: {style} | 目标字数: {target_words}"
),
"world": (
"请为小说《{title}》设计世界观设定, 包括:\n"
"1. 时代背景\n"
"2. 主要地点\n"
"3. 力量体系 (如有)\n"
"4. 社会结构\n"
"类型: {genre} | 风格: {style}"
),
"characters": (
"请为小说《{title}》设计主要角色表。\n"
"每个角色单独一段, 以【角色】名字 开头, 包含:\n"
"名字 / 定位 / 性格 / 动机 / 成长弧线。\n"
"类型: {genre} | 风格: {style}"
),
"outline": (
"请为小说《{title}》规划三幕结构与卷章大纲。\n"
"格式: 第N卷 / 第N章 标题 — 一句话概要\n"
"预估总章数按目标字数 {target_words} 除以每章 5000 字计算。\n"
"类型: {genre} | 风格: {style}"
),
"foreshadowing": (
"请为小说《{title}》设计伏笔计划。\n"
"每条伏笔单独一段, 以【伏笔】开头, 包含:\n"
"描述 / 埋设位置 (第几卷第几章) / 回收位置。\n"
"类型: {genre} | 风格: {style}"
),
}
def _format_inputs(inputs):
"""Return (title, genre, style, target_words, reference_novel, confirmed)."""
return (
inputs.get("title", "未命名"),
inputs.get("genre", "未指定"),
inputs.get("style", "未指定"),
inputs.get("target_words", "未指定"),
inputs.get("reference_novel"),
inputs.get("confirmed", {}),
)
def _confirmed_context(confirmed):
"""Render previously confirmed sections as context for the next prompt."""
if not confirmed:
return ""
parts = []
for sec in SECTIONS:
text = confirmed.get(sec)
if text:
parts.append(f"【已确认 - {sec}\n{text}")
return "\n\n".join(parts)
def build_section_prompt(section, inputs):
"""Build the messages list for a given section.
``inputs`` is a dict with keys: title, genre, style, target_words,
reference_novel (optional), confirmed (dict of previous section texts).
Returns a list of ``{"role": ..., "content": ...}`` dicts ready for
the LLM chat API.
"""
title, genre, style, target_words, reference_novel, confirmed = _format_inputs(inputs)
template = _SECTION_PROMPTS.get(section)
if template is None:
raise ValueError(f"unknown section: {section}")
user_prompt = template.format(
title=title,
genre=genre,
style=style,
target_words=target_words,
)
if reference_novel:
user_prompt += f"\n\n参考小说: 《{reference_novel}》, 参考其节奏与结构但不抄袭。"
ctx = _confirmed_context(confirmed)
if ctx:
user_prompt = f"以下是已确认的前序设定:\n\n{ctx}\n\n---\n\n{user_prompt}"
return [
{"role": "system", "content": SYSTEM_PROMPT},
{"role": "user", "content": user_prompt},
]
def stream_section(section, inputs):
"""Generator yielding SSE frames for a section.
Emits ``section_start`` → token frames → ``section_end`` (with full
accumulated content). Uses :func:`llm.make_token_stream` under the hood.
"""
messages = build_section_prompt(section, inputs)
yield llm._sse("section_start", {"section": section})
parts = []
def _on_token(t):
parts.append(t)
yield from llm.make_token_stream(messages, _on_token, max_tokens=4096)
full_text = "".join(parts)
yield llm._sse("section_end", {"section": section, "content": full_text})

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"""LLM client: streaming and non-streaming chat completions, SSE framing.
Pure functions — no Flask imports. Uses ``requests`` for HTTP against an
OpenAI-compatible endpoint (``config.LLM_URL``). The ``_sse`` helper is
shared by deconstruct / chapter_writer so every SSE stream uses the same
wire format.
"""
import json
import logging
import time
import requests as http_requests
import config
logger = logging.getLogger(__name__)
_KEEPALIVE_INTERVAL = 15 # seconds
def _sse(event, payload):
"""Return a single SSE frame: ``event: <event>\\ndata: <json>\\n\\n``."""
return f"event: {event}\ndata: {json.dumps(payload, ensure_ascii=False)}\n\n"
def stream_chat(messages, max_tokens=4096, model=None, timeout=None):
"""Generator yielding raw token strings from a streaming chat completion.
POSTs to ``{config.LLM_URL}/chat/completions`` with ``stream=True``.
Parses ``data:`` lines, handles ``[DONE]`` terminator, extracts
``choices[0].delta.content``. Raises ``RuntimeError`` on HTTP failure.
"""
url = f"{config.LLM_URL}/chat/completions"
body = {
"model": model or config.LLM_MODEL,
"messages": messages,
"stream": True,
"max_tokens": max_tokens,
}
resp = http_requests.post(url, json=body, stream=True, timeout=timeout or config.LLM_TIMEOUT)
resp.raise_for_status()
for line in resp.iter_lines():
if not line:
continue
line = line.decode("utf-8") if isinstance(line, bytes) else line
if not line.startswith("data: "):
continue
chunk_data = line[6:]
if chunk_data.strip() == "[DONE]":
break
try:
chunk = json.loads(chunk_data)
except json.JSONDecodeError:
continue
delta = chunk.get("choices", [{}])[0].get("delta", {})
token_text = delta.get("content", "")
if token_text:
yield token_text
def complete_chat(messages, max_tokens=2048, model=None, timeout=None):
"""Non-streaming call returning the assistant content string."""
url = f"{config.LLM_URL}/chat/completions"
body = {
"model": model or config.LLM_MODEL,
"messages": messages,
"stream": False,
"max_tokens": max_tokens,
}
resp = http_requests.post(url, json=body, timeout=timeout or config.LLM_TIMEOUT)
resp.raise_for_status()
return resp.json().get("choices", [{}])[0].get("message", {}).get("content", "")
def make_token_stream(messages, on_token, max_tokens=4096):
"""Generator wrapping :func:`stream_chat` with SSE framing + keepalive.
Yields ``_sse('token', {'text': t})`` for each token. Calls
``on_token(t)`` per token so callers can accumulate the full text.
Emits ``: keepalive\\n\\n`` comments if >15 s silence between chunks.
On exception yields ``_sse('error', {'error': ...})`` and stops.
"""
last_emit = time.time()
try:
for token in stream_chat(messages, max_tokens=max_tokens):
now = time.time()
if now - last_emit > _KEEPALIVE_INTERVAL:
yield ": keepalive\n\n"
yield _sse("token", {"text": token})
on_token(token)
last_emit = time.time()
except Exception as exc:
logger.exception("make_token_stream: LLM error")
yield _sse("error", {"error": str(exc)})