feat(api): streaming des fichiers livres avec support Range

Réponses 206 partielles avec Content-Range/Accept-Ranges pour la
lecture PDF, types MIME explicites par format, en-tête
Content-Disposition UTF-8 et nosniff.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/api/src/books/books.controller.ts

@@ -1,4 +1,4 @@
-import { Controller, Get, Param, Query, Res, UseGuards } from "@nestjs/common";
+import { Controller, Get, Headers, Param, Query, Res, UseGuards } from "@nestjs/common";
 import { FastifyReply } from "fastify";
 import { lookup } from "mime-types";
 import { BookQueryDto, BookQuerySchema } from "@readabook/shared";
@@ -40,10 +40,17 @@ export class BooksController {
   }
 
   @Get(":id/file")
-  file(@Param("id") id: string, @Res() reply: FastifyReply) {
-    const { book, stream } = this.books.streamFile(Number(id));
-    reply.header("Content-Type", lookup(book.filePath) || "application/octet-stream");
-    reply.header("Content-Disposition", `inline; filename="${encodeURIComponent(book.title)}.${book.format}"`);
+  file(@Param("id") id: string, @Headers("range") range: string | undefined, @Res() reply: FastifyReply) {
+    const { book, stream, contentLength, contentType, end, partial, size, start } = this.books.streamFile(Number(id), range);
+    if (partial) {
+      reply.code(206);
+      reply.header("Content-Range", `bytes ${start}-${end}/${size}`);
+    }
+    reply.header("Accept-Ranges", "bytes");
+    reply.header("Content-Length", String(contentLength));
+    reply.header("Content-Type", contentType || lookup(book.filePath) || "application/octet-stream");
+    reply.header("Content-Disposition", `inline; filename*=UTF-8''${encodeURIComponent(`${book.title}.${book.format}`)}`);
+    reply.header("X-Content-Type-Options", "nosniff");
     return reply.send(stream);
   }
 

apps/api/src/books/books.service.ts

@@ -1,5 +1,5 @@
-import { BadRequestException, Injectable, NotFoundException } from "@nestjs/common";
-import { createReadStream, existsSync } from "node:fs";
+import { BadRequestException, HttpException, HttpStatus, Injectable, NotFoundException } from "@nestjs/common";
+import { createReadStream, existsSync, statSync } from "node:fs";
 import { extname } from "node:path";
 import { and, eq, sql } from "drizzle-orm";
 import { BookQueryDto } from "@readabook/shared";
@@ -53,12 +53,22 @@ export class BooksService {
     return book;
   }
 
-  streamFile(id: number) {
+  streamFile(id: number, range?: string) {
     const book = this.get(id);
     if (!existsSync(book.filePath)) {
       throw new NotFoundException("Book file not found on disk");
     }
-    return { book, stream: createReadStream(book.filePath) };
+    const size = statSync(book.filePath).size;
+    const byteRange = parseByteRange(range, size);
+    const stream = createReadStream(book.filePath, { start: byteRange.start, end: byteRange.end });
+    return {
+      book,
+      stream,
+      contentType: bookContentType(book.format),
+      contentLength: byteRange.end - byteRange.start + 1,
+      size,
+      ...byteRange
+    };
   }
 
   streamCover(id: number) {
@@ -108,6 +118,38 @@ export class BooksService {
   }
 }
 
+function parseByteRange(range: string | undefined, size: number): { start: number; end: number; partial: boolean } {
+  if (!range) return { start: 0, end: Math.max(size - 1, 0), partial: false };
+  const match = range.match(/^bytes=(\d*)-(\d*)$/);
+  if (!match || size <= 0) {
+    throw new HttpException("Requested range not satisfiable", HttpStatus.REQUESTED_RANGE_NOT_SATISFIABLE);
+  }
+
+  const [, rawStart, rawEnd] = match;
+  let start: number;
+  let end: number;
+  if (!rawStart && rawEnd) {
+    const suffixLength = Number(rawEnd);
+    start = Math.max(size - suffixLength, 0);
+    end = size - 1;
+  } else {
+    start = Number(rawStart);
+    end = rawEnd ? Number(rawEnd) : size - 1;
+  }
+  if (!Number.isInteger(start) || !Number.isInteger(end) || start < 0 || end < start || start >= size) {
+    throw new HttpException("Requested range not satisfiable", HttpStatus.REQUESTED_RANGE_NOT_SATISFIABLE);
+  }
+  return { start, end: Math.min(end, size - 1), partial: true };
+}
+
+function bookContentType(format: string): string {
+  if (format === "epub") return "application/epub+zip";
+  if (format === "pdf") return "application/pdf";
+  if (format === "cbz") return "application/vnd.comicbook+zip";
+  if (format === "cbr") return "application/vnd.comicbook-rar";
+  return "application/octet-stream";
+}
+
 function lookupMime(entryName: string): string {
   const extension = extname(entryName).toLowerCase();
   if (extension === ".png") return "image/png";