first commit

2026-01-05 19:51:09 +08:00
commit 2d8303808d
15 changed files with 2596 additions and 0 deletions
@@ -0,0 +1,197 @@
+import { parseStyle, STYLES, type SummaryStyle } from "./styles";
+
+export type AiBinding = { run: (model: string, input: unknown) => Promise<unknown> };
+
+export type ApiEnv = {
+  KV?: KVNamespace;
+  AI?: AiBinding;
+  MODEL?: string;
+};
+
+export type SummaryRecord = {
+  url: string;
+  style: SummaryStyle;
+  summary: string;
+  sourceHash: string;
+  model: string;
+  createdAt: string;
+  updatedAt: string;
+};
+
+const MAX_INPUT_CHARS = 20_000;
+const MAX_URL_CHARS = 500;
+
+function withCors(response: Response): Response {
+  const headers = new Headers(response.headers);
+  headers.set("Access-Control-Allow-Origin", "*");
+  headers.set("Access-Control-Allow-Methods", "GET,POST,OPTIONS");
+  headers.set("Access-Control-Allow-Headers", "Content-Type");
+  headers.set("Access-Control-Max-Age", "86400");
+  headers.set("Vary", "Origin");
+  return new Response(response.body, {
+    status: response.status,
+    statusText: response.statusText,
+    headers,
+  });
+}
+
+function json(data: unknown, init: ResponseInit = {}): Response {
+  const headers = new Headers(init.headers);
+  headers.set("Content-Type", "application/json; charset=utf-8");
+  return withCors(new Response(JSON.stringify(data, null, 2), { ...init, headers }));
+}
+
+function badRequest(message: string, details?: unknown): Response {
+  return json({ error: message, details }, { status: 400 });
+}
+
+function serverError(message: string, details?: unknown): Response {
+  return json({ error: message, details }, { status: 500 });
+}
+
+function normalizeRelativeUrl(input: string): string {
+  const trimmed = input.trim();
+  if (!trimmed) return "/";
+  try {
+    const u = new URL(trimmed);
+    return (u.pathname + u.search).slice(0, MAX_URL_CHARS) || "/";
+  } catch {
+    const withSlash = trimmed.startsWith("/") ? trimmed : `/${trimmed}`;
+    return withSlash.slice(0, MAX_URL_CHARS);
+  }
+}
+
+function base64Url(bytes: ArrayBuffer): string {
+  const bin = String.fromCharCode(...new Uint8Array(bytes));
+  const b64 = btoa(bin);
+  return b64.replaceAll("+", "-").replaceAll("/", "_").replaceAll("=", "");
+}
+
+async function sha256(text: string): Promise<string> {
+  const data = new TextEncoder().encode(text);
+  const digest = await crypto.subtle.digest("SHA-256", data);
+  return base64Url(digest);
+}
+
+function kvKey(url: string, style: SummaryStyle): string {
+  return `summary:${style}:${encodeURIComponent(url)}`;
+}
+
+async function readJson<T>(request: Request): Promise<T> {
+  const contentType = request.headers.get("Content-Type") || "";
+  if (!contentType.toLowerCase().includes("application/json")) {
+    throw new Error("Content-Type must be application/json");
+  }
+  return (await request.json()) as T;
+}
+
+export async function handleApi(request: Request, env: ApiEnv): Promise<Response> {
+  const url = new URL(request.url);
+
+  if (request.method === "OPTIONS") return withCors(new Response(null, { status: 204 }));
+
+  if (url.pathname === "/api/styles" && request.method === "GET") {
+    return json({
+      styles: Object.entries(STYLES).map(([key, spec]) => ({
+        key,
+        label: spec.label,
+        maxCharsHint: spec.maxCharsHint,
+      })),
+    });
+  }
+
+  if (url.pathname === "/api/summary" && request.method === "GET") {
+    if (!env.KV) return serverError("KV binding not configured (KV).");
+    const relativeUrl = normalizeRelativeUrl(url.searchParams.get("url") || "/");
+    const style = parseStyle(url.searchParams.get("style"));
+    const record = (await env.KV.get(kvKey(relativeUrl, style), {
+      type: "json",
+    })) as SummaryRecord | null;
+    if (!record) return json({ error: "Not found" }, { status: 404 });
+    return json({ ...record, cached: true });
+  }
+
+  if (url.pathname === "/api/summary" && request.method === "POST") {
+    if (!env.KV) return serverError("KV binding not configured (KV).");
+    if (!env.AI?.run) return serverError("Workers AI binding not configured (AI).");
+
+    type Body = {
+      url: string;
+      style?: string;
+      text: string;
+      force?: boolean;
+    };
+
+    let body: Body;
+    try {
+      body = await readJson<Body>(request);
+    } catch (err) {
+      return badRequest((err as Error).message);
+    }
+
+    if (!body?.url) return badRequest("Missing 'url'.");
+    if (!body?.text) return badRequest("Missing 'text'.");
+
+    const relativeUrl = normalizeRelativeUrl(body.url);
+    const style = parseStyle(body.style ?? null);
+    const text = body.text.trim().slice(0, MAX_INPUT_CHARS);
+    const sourceHash = await sha256(text);
+
+    const key = kvKey(relativeUrl, style);
+    const existing = (await env.KV.get(key, { type: "json" })) as SummaryRecord | null;
+    if (existing && existing.sourceHash === sourceHash && !body.force) {
+      return json({ ...existing, cached: true });
+    }
+
+    const model = env.MODEL || "@cf/meta/llama-3.1-8b-instruct";
+    const spec = STYLES[style];
+
+    const messages = [
+      {
+        role: "system" as const,
+        content:
+          "你是一个中文摘要助手。输入是网页文章正文的纯文本（可能包含少量导航/广告残留）。" +
+          "输出必须严格遵循用户指定的风格要求。不要编造信息；遇到缺失信息就写“文中未提及”。" +
+          "不要输出与摘要无关的前后缀（例如：'好的，以下是摘要'）。",
+      },
+      {
+        role: "user" as const,
+        content:
+          `风格：${style}（${spec.label}）\n` +
+          `要求：${spec.instructions}\n\n` +
+          `文章URL：${relativeUrl}\n` +
+          "正文：\n" +
+          text,
+      },
+    ];
+
+    let summaryText: string | undefined;
+    try {
+      const result = (await env.AI.run(model, {
+        messages,
+        temperature: 0.2,
+      })) as { response?: string };
+      summaryText = result?.response?.trim();
+    } catch (err) {
+      return serverError("AI generation failed.", { message: (err as Error).message });
+    }
+
+    if (!summaryText) return serverError("AI returned empty response.");
+
+    const now = new Date().toISOString();
+    const record: SummaryRecord = {
+      url: relativeUrl,
+      style,
+      summary: summaryText,
+      sourceHash,
+      model,
+      createdAt: existing?.createdAt ?? now,
+      updatedAt: now,
+    };
+
+    await env.KV.put(key, JSON.stringify(record));
+    return json({ ...record, cached: false });
+  }
+
+  return json({ error: "Not found" }, { status: 404 });
+}
@@ -0,0 +1,42 @@
+export type SummaryStyle = "tldr" | "bullets" | "outline" | "keywords";
+
+export type StyleSpec = {
+  label: string;
+  instructions: string;
+  maxCharsHint: number;
+};
+
+export const STYLES: Record<SummaryStyle, StyleSpec> = {
+  tldr: {
+    label: "TL;DR",
+    instructions:
+      "用中文输出 2-3 句话的摘要，先给结论再给理由；尽量具体，避免空话；不要输出标题或列表。",
+    maxCharsHint: 450,
+  },
+  bullets: {
+    label: "要点",
+    instructions:
+      "用中文输出 5-8 条要点，每条 15-35 字，使用 Markdown 列表（以 '- ' 开头）；不要重复句式；不要输出多余解释。",
+    maxCharsHint: 650,
+  },
+  outline: {
+    label: "结构化",
+    instructions:
+      "用中文输出 3-6 个小节，每小节一个短标题（不超过 10 字）+ 1-2 句说明；使用 Markdown：'### 标题' 换行后写内容。",
+    maxCharsHint: 900,
+  },
+  keywords: {
+    label: "关键词",
+    instructions:
+      "用中文输出 8-12 个关键词/短语，用顿号或逗号分隔；不加编号、不加解释、不要换行。",
+    maxCharsHint: 200,
+  },
+};
+
+export function parseStyle(value: string | null): SummaryStyle {
+  if (!value) return "tldr";
+  const normalized = value.trim().toLowerCase();
+  if (normalized in STYLES) return normalized as SummaryStyle;
+  return "tldr";
+}
+
@@ -0,0 +1,32 @@
+import { handleApi, type ApiEnv } from "./api";
+
+type Env = ApiEnv & {
+  ASSETS?: Fetcher;
+};
+
+function withCors(response: Response): Response {
+  const headers = new Headers(response.headers);
+  headers.set("Access-Control-Allow-Origin", "*");
+  headers.set("Access-Control-Allow-Methods", "GET,POST,OPTIONS");
+  headers.set("Access-Control-Allow-Headers", "Content-Type");
+  headers.set("Access-Control-Max-Age", "86400");
+  headers.set("Cross-Origin-Resource-Policy", "cross-origin");
+  headers.set("Vary", "Origin");
+  return new Response(response.body, {
+    status: response.status,
+    statusText: response.statusText,
+    headers,
+  });
+}
+
+export default {
+  async fetch(request: Request, env: Env): Promise<Response> {
+    const url = new URL(request.url);
+    if (url.pathname.startsWith("/api/")) return handleApi(request, env);
+    if (env.ASSETS) {
+      const res = await env.ASSETS.fetch(request);
+      return withCors(res);
+    }
+    return withCors(new Response("Not found", { status: 404 }));
+  },
+};