251 lines
9.1 KiB
TypeScript
251 lines
9.1 KiB
TypeScript
import JSZip from "jszip";
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const MAX_TEXT_CHARS = 120_000;
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function clampText(input: string, maxChars = MAX_TEXT_CHARS): string {
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const trimmed = String(input || "").replace(/\s+\n/g, "\n").trim();
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if (!trimmed) return "";
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if (trimmed.length <= maxChars) return trimmed;
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return `${trimmed.slice(0, maxChars)}…`;
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}
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function decodeXmlEntities(input: string): string {
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return input
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.replace(/</g, "<")
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.replace(/>/g, ">")
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.replace(/&/g, "&")
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.replace(/"/g, '"')
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.replace(/'/g, "'")
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.replace(/&#x([0-9a-fA-F]+);/g, (_, hex) => {
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const code = Number.parseInt(hex, 16);
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if (!Number.isFinite(code)) return "";
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return String.fromCodePoint(code);
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})
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.replace(/&#(\d+);/g, (_, dec) => {
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const code = Number.parseInt(dec, 10);
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if (!Number.isFinite(code)) return "";
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return String.fromCodePoint(code);
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});
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}
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function getExtension(fileName: string | null | undefined): string {
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const raw = String(fileName ?? "").trim().toLowerCase();
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const idx = raw.lastIndexOf(".");
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if (idx === -1) return "";
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return raw.slice(idx + 1).replace(/[^a-z0-9]+/g, "");
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}
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function detectKind(args: { mimeType?: string | null; fileName?: string | null }): "pdf" | "docx" | "pptx" | "xlsx" | null {
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const mime = String(args.mimeType ?? "").toLowerCase().trim();
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if (mime === "application/pdf") return "pdf";
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if (mime === "application/vnd.openxmlformats-officedocument.wordprocessingml.document") return "docx";
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if (mime === "application/vnd.openxmlformats-officedocument.presentationml.presentation") return "pptx";
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if (mime === "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet") return "xlsx";
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const ext = getExtension(args.fileName ?? null);
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if (ext === "pdf") return "pdf";
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if (ext === "docx") return "docx";
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if (ext === "pptx") return "pptx";
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if (ext === "xlsx") return "xlsx";
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return null;
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}
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function extractTextFromXmlByTag(xml: string, tagName: string): string {
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const out: string[] = [];
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const re = new RegExp(`<${tagName}[^>]*>([\\s\\S]*?)<\\/${tagName}>`, "g");
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let m: RegExpExecArray | null;
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while ((m = re.exec(xml))) {
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const raw = m[1] ?? "";
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const clean = decodeXmlEntities(raw).replace(/\s+/g, " ").trim();
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if (clean) out.push(clean);
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}
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return out.join(" ").trim();
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}
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function extractDocxText(documentXml: string): string {
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const paras = documentXml.split(/<w:p[\s>]/g);
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const out: string[] = [];
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for (const p of paras) {
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const line: string[] = [];
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const re = /<w:t[^>]*>([\s\S]*?)<\/w:t>/g;
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let m: RegExpExecArray | null;
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while ((m = re.exec(p))) {
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const raw = m[1] ?? "";
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const clean = decodeXmlEntities(raw).replace(/\s+/g, " ").trim();
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if (clean) line.push(clean);
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}
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const joined = line.join("").trim();
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if (joined) out.push(joined);
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}
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return out.join("\n").trim();
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}
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function extractPptxText(slideXmls: string[]): string {
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const out: string[] = [];
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for (const xml of slideXmls) {
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const line = extractTextFromXmlByTag(xml, "a:t");
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if (line) out.push(line);
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}
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return out.join("\n\n").trim();
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}
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function extractXlsxText(args: { sharedStringsXml: string | null; sheetXmls: string[] }): string {
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const sharedStrings: string[] = [];
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if (args.sharedStringsXml) {
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const re = /<t[^>]*>([\s\S]*?)<\/t>/g;
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let m: RegExpExecArray | null;
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while ((m = re.exec(args.sharedStringsXml))) {
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const raw = m[1] ?? "";
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const clean = decodeXmlEntities(raw).replace(/\s+/g, " ").trim();
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if (clean) sharedStrings.push(clean);
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}
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}
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const out: string[] = [];
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for (const xml of args.sheetXmls) {
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const rows = xml.split(/<row[\s>]/g);
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for (const r of rows) {
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const cells: string[] = [];
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// t="s" => sharedStrings index；t="inlineStr" => <is><t>...；默认 => <v>number
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const cellRe = /<c\b[^>]*?(?:t="([^"]+)")?[^>]*>([\s\S]*?)<\/c>/g;
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let cm: RegExpExecArray | null;
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while ((cm = cellRe.exec(r))) {
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const t = (cm[1] ?? "").trim();
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const body = cm[2] ?? "";
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if (t === "inlineStr") {
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const inline = extractTextFromXmlByTag(body, "t");
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if (inline) cells.push(inline);
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continue;
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}
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const vMatch = /<v>([\s\S]*?)<\/v>/.exec(body);
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if (!vMatch) continue;
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const rawV = decodeXmlEntities(String(vMatch[1] ?? "")).trim();
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if (!rawV) continue;
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if (t === "s") {
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const idx = Number.parseInt(rawV, 10);
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const s = Number.isFinite(idx) ? (sharedStrings[idx] ?? "") : "";
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if (s) cells.push(s);
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} else {
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cells.push(rawV);
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}
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}
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const line = cells.join(" ").replace(/\s+/g, " ").trim();
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if (line) out.push(line);
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}
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}
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return out.join("\n").trim();
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}
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export type AttachmentExtractOk = {
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ok: true;
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strategy: string;
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text: string;
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meta?: Record<string, unknown>;
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};
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export type AttachmentExtractResult =
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| AttachmentExtractOk
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| { ok: false; strategy: string; reason: string; meta?: Record<string, unknown> };
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export async function extractTextFromAttachment(args: {
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mimeType: string | null;
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fileName: string | null;
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bytes: ArrayBuffer;
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}): Promise<AttachmentExtractResult> {
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const kind = detectKind({ mimeType: args.mimeType, fileName: args.fileName });
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if (!kind) {
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return { ok: false, strategy: "unsupported", reason: "暂不支持该附件类型" };
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}
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if (kind === "pdf") {
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try {
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const mod = await import("pdfjs-dist/legacy/build/pdf.mjs");
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const data = new Uint8Array(args.bytes);
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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const loadingTask = (mod as any).getDocument({ data });
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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const pdf = await (loadingTask as any).promise;
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const out: string[] = [];
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const pages = Number(pdf?.numPages ?? 0) || 0;
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for (let i = 1; i <= pages; i += 1) {
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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const page = await (pdf as any).getPage(i);
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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const content = await (page as any).getTextContent();
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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const items = Array.isArray((content as any)?.items) ? (content as any).items : [];
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const line = items
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.map((it: any) => (typeof it?.str === "string" ? it.str : ""))
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.join(" ")
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.replace(/\s+/g, " ")
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.trim();
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if (line) out.push(line);
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}
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const text = clampText(out.join("\n\n"));
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if (!text) {
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return { ok: false, strategy: "pdfjs", reason: "未提取到可用文本", meta: { pages } };
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}
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return { ok: true, strategy: "pdfjs", text, meta: { pages } };
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} catch (err) {
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const message = err instanceof Error ? err.message : String(err);
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return { ok: false, strategy: "pdfjs", reason: message };
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}
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}
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try {
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const zip = await JSZip.loadAsync(args.bytes);
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if (kind === "docx") {
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const file = zip.file("word/document.xml");
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const xml = file ? await file.async("string") : "";
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const text = clampText(extractDocxText(xml));
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if (!text) return { ok: false, strategy: "docx.xml", reason: "未提取到可用文本" };
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return { ok: true, strategy: "docx.xml", text };
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}
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if (kind === "pptx") {
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const slideFiles = Object.keys(zip.files)
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.filter((p) => /^ppt\/slides\/slide\d+\.xml$/i.test(p))
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.sort((a, b) => a.localeCompare(b, undefined, { numeric: true }));
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const slideXmls: string[] = [];
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for (const p of slideFiles) {
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const f = zip.file(p);
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if (!f) continue;
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// eslint-disable-next-line no-await-in-loop
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slideXmls.push(await f.async("string"));
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}
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const text = clampText(extractPptxText(slideXmls));
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if (!text) return { ok: false, strategy: "pptx.xml", reason: "未提取到可用文本" };
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return { ok: true, strategy: "pptx.xml", text, meta: { slides: slideXmls.length } };
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}
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if (kind === "xlsx") {
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const sharedStringsXml = await (async () => {
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const f = zip.file("xl/sharedStrings.xml");
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if (!f) return null;
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return await f.async("string");
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})();
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const sheetFiles = Object.keys(zip.files)
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.filter((p) => /^xl\/worksheets\/sheet\d+\.xml$/i.test(p))
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.sort((a, b) => a.localeCompare(b, undefined, { numeric: true }));
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const sheetXmls: string[] = [];
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for (const p of sheetFiles) {
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const f = zip.file(p);
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if (!f) continue;
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// eslint-disable-next-line no-await-in-loop
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sheetXmls.push(await f.async("string"));
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}
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const text = clampText(extractXlsxText({ sharedStringsXml, sheetXmls }));
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if (!text) return { ok: false, strategy: "xlsx.xml", reason: "未提取到可用文本" };
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return { ok: true, strategy: "xlsx.xml", text, meta: { sheets: sheetXmls.length } };
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}
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return { ok: false, strategy: "unsupported", reason: "暂不支持该附件类型" };
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} catch (err) {
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const message = err instanceof Error ? err.message : String(err);
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return { ok: false, strategy: "zip", reason: message };
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}
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}
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