""" PDF 生成服务（从 services 迁入 memoir feature） """ from app.core.logging import get_logger from io import BytesIO from typing import List, Optional import httpx from PIL import Image from reportlab.lib.pagesizes import A4 from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle from reportlab.lib.units import inch from reportlab.platypus import ( Image as ReportLabImage, PageBreak, Paragraph, SimpleDocTemplate, Spacer, ) from reportlab.pdfbase import pdfmetrics from reportlab.pdfbase.cidfonts import UnicodeCIDFont from app.features.memoir.asset_resolver import ( collect_asset_ids_from_markdown, split_markdown_by_asset_refs, strip_legacy_image_placeholders, ) from app.features.memoir.chapter_markdown_compose import ( materialize_chapter_pdf_markdown_from_loaded_chapter, ) from app.features.memoir.helpers import ( _chapter_markdown, sections_to_content_and_images, ) def _chapter_markdown_for_pdf(chapter) -> str: """有 story 编排时 PDF 使用「## 故事名 + 正文」物化；否则沿用章节 canonical。""" links = getattr(chapter, "story_links", None) or [] if links and any(getattr(l, "story", None) for l in links): return materialize_chapter_pdf_markdown_from_loaded_chapter(chapter) return _chapter_markdown(chapter) from app.features.memoir.memoir_images.parser import PLACEHOLDER_RE from app.features.memoir.memoir_images.schema import ( IMAGE_STATUS_COMPLETED, normalize_image_assets, ) from app.features.memoir.memoir_images.storage import ( CosDownloadUrlError, TencentCosStorageService, mark_image_delivery_unavailable, resolve_image_storage_key, ) logger = get_logger(__name__) def strip_image_placeholders(text: str) -> str: return PLACEHOLDER_RE.sub("", text or "").strip() def split_content_blocks(content: str, images: list[dict]) -> list[dict]: blocks: list[dict] = [] remaining = content for image in sorted(images or [], key=lambda item: item.get("index", 0)): placeholder = image.get("placeholder") if not placeholder or placeholder not in remaining: continue before, remaining = remaining.split(placeholder, 1) cleaned_before = strip_image_placeholders(before) if cleaned_before: blocks.append({"type": "text", "value": cleaned_before}) if image.get("status") == IMAGE_STATUS_COMPLETED and image.get("url"): blocks.append({"type": "image", "url": image["url"]}) cleaned_remaining = strip_image_placeholders(remaining) if cleaned_remaining: blocks.append({"type": "text", "value": cleaned_remaining}) return blocks def _prepare_pdf_image_assets(images: list[dict]) -> list[dict]: storage = TencentCosStorageService.from_env() prepared_assets: list[dict] = [] for item in normalize_image_assets(images): asset = dict(item) storage_key = resolve_image_storage_key(asset) if asset.get("status") == IMAGE_STATUS_COMPLETED and storage_key: try: asset["url"] = storage.get_download_url(storage_key) except CosDownloadUrlError as exc: logger.warning( "PDF 图片签名失败: key=%s, retryable=%s, request_id=%s, error=%s", storage_key, exc.retryable, exc.request_id, exc, ) asset = mark_image_delivery_unavailable(asset) except Exception as exc: logger.warning("PDF 图片签名失败: key=%s, error=%s", storage_key, exc) asset = mark_image_delivery_unavailable(asset) prepared_assets.append(asset) return prepared_assets def _fit_image_size( image_bytes: bytes, max_width: float, max_height: float ) -> tuple[float, float]: with Image.open(BytesIO(image_bytes)) as image: width, height = image.size if width <= 0 or height <= 0: return max_width, max_height scale = min(max_width / width, max_height / height) return width * scale, height * scale class PDFService: def __init__(self): try: pdfmetrics.registerFont(UnicodeCIDFont("STSong-Light")) self.chinese_font = "STSong-Light" except Exception: self.chinese_font = "Helvetica" async def _fetch_image_bytes(self, url: str) -> bytes | None: try: async with httpx.AsyncClient(timeout=30) as client: response = await client.get(url) response.raise_for_status() return response.content except Exception as exc: logger.warning("PDF 图片下载失败: url=%s, error=%s", url, exc) return None async def generate_pdf( self, book, chapters: List, asset_url_map: Optional[dict[str, str]] = None, ) -> bytes: buffer = BytesIO() doc = SimpleDocTemplate(buffer, pagesize=A4) styles = getSampleStyleSheet() title_style = ParagraphStyle( "CustomTitle", parent=styles["Heading1"], fontSize=24, spaceAfter=30, alignment=1, fontName=self.chinese_font, ) heading_style = ParagraphStyle( "CustomHeading", parent=styles["Heading1"], fontSize=18, spaceAfter=12, fontName=self.chinese_font, ) normal_style = ParagraphStyle( "CustomNormal", parent=styles["Normal"], fontSize=12, leading=18, fontName=self.chinese_font, ) story = [] story.append(Paragraph(book.title, title_style)) story.append(Spacer(1, 0.5 * inch)) story.append(PageBreak()) story.append(Paragraph("目录", heading_style)) story.append(Spacer(1, 0.2 * inch)) for i, chapter in enumerate(chapters, 1): story.append(Paragraph(f"{i}. {chapter.title}", normal_style)) story.append(PageBreak()) for chapter in chapters: story.append(Paragraph(chapter.title, heading_style)) story.append(Spacer(1, 0.2 * inch)) # 有 story_links 时按章节内故事注入 ## 标题（与物化章节正文不含故事标题区分） markdown = _chapter_markdown_for_pdf(chapter) _, images_list = sections_to_content_and_images(chapter) if not markdown: markdown = getattr(chapter, "content", "") or "" if not images_list: images_list = list(getattr(chapter, "images", None) or []) prepared_images = _prepare_pdf_image_assets(images_list) blocks: list[dict] if asset_url_map and collect_asset_ids_from_markdown(markdown): blocks = split_markdown_by_asset_refs( markdown, lambda aid: asset_url_map.get(aid) if asset_url_map else None, ) for b in blocks: if b.get("type") == "text": b["value"] = strip_legacy_image_placeholders( b.get("value") or "" ) else: blocks = split_content_blocks(markdown, prepared_images) for block in blocks: if block["type"] == "text": paragraphs = block["value"].split("\n\n") for para in paragraphs: if para.strip(): story.append(Paragraph(para.strip(), normal_style)) story.append(Spacer(1, 0.1 * inch)) elif block["type"] == "image": image_bytes = await self._fetch_image_bytes(block["url"]) if image_bytes: try: width, height = _fit_image_size( image_bytes, max_width=5 * inch, max_height=3.75 * inch, ) img = ReportLabImage( BytesIO(image_bytes), width=width, height=height ) story.append(img) story.append(Spacer(1, 0.2 * inch)) except Exception as exc: logger.warning("PDF 图片嵌入失败: %s", exc) story.append(PageBreak()) doc.build(story) buffer.seek(0) return buffer.read() pdf_service = PDFService()