From d99253ba7957c8106cb3c1e6980ecc2e28070881 Mon Sep 17 00:00:00 2001
From: Schalli <kschaller@ctl.de>
Date: Tue, 7 Jul 2026 15:34:02 +0200
Subject: [PATCH] feat(favorites): GET /favorites/:id/icon proxy endpoint

Ownership-scoped (userId, matching update/remove) icon byte proxy.
Loads the row's stored iconUrl server-side and streams it through
IconDiscoveryService.fetchIconBytes -- never accepts a client-supplied
URL, so this can't become an open SSRF proxy.

Not-found/not-owned/no-icon -> 404. Upstream fetch failure (unreachable,
timeout, non-image, SSRF-blocked) -> 502, never a 200 with a placeholder.
Success sets Cache-Control so the browser doesn't refetch every load.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
---
 .../api/src/favorites/favorites.controller.ts | 29 ++++++++++++++-
 apps/api/src/favorites/favorites.service.ts   | 36 ++++++++++++++++++-
 2 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/apps/api/src/favorites/favorites.controller.ts b/apps/api/src/favorites/favorites.controller.ts
index 355290b..a31a060 100644
--- a/apps/api/src/favorites/favorites.controller.ts
+++ b/apps/api/src/favorites/favorites.controller.ts
@@ -10,8 +10,9 @@ import {
   Post,
   Query,
   Req,
+  Res,
 } from '@nestjs/common';
-import { Request } from 'express';
+import { Request, Response } from 'express';
 import { CreateFavoriteDto } from './dto/create-favorite.dto';
 import { UpdateFavoriteDto } from './dto/update-favorite.dto';
 import { FavoritesService } from './favorites.service';
@@ -66,6 +67,32 @@ export class FavoritesController {
     return this.favoritesService.create(userId, tenantId, dto);
   }
 
+  /**
+   * GET /favorites/:id/icon — streams the stored icon bytes for a favorite
+   * owned by the caller, from Tessera's own origin. This avoids the browser
+   * blocking a cross-origin <img> hotlink when the external site sends
+   * Cross-Origin-Resource-Policy: same-origin (e.g. claude.ai).
+   *
+   * Takes only a FavoriteLink id — never a client-supplied URL — so this
+   * cannot be used as an arbitrary-URL SSRF proxy (T-QFIP-01).
+   */
+  @Get(':id/icon')
+  async getIcon(
+    @Param('id') id: string,
+    @Req() req: Request,
+    @Res() res: Response,
+  ) {
+    const { userId } = this.extractContext(req);
+    const { contentType, body } = await this.favoritesService.getIconBytes(
+      id,
+      userId,
+    );
+
+    res.setHeader('Content-Type', contentType);
+    res.setHeader('Cache-Control', 'public, max-age=86400');
+    res.send(body);
+  }
+
   @Patch(':id')
   async update(
     @Param('id') id: string,
diff --git a/apps/api/src/favorites/favorites.service.ts b/apps/api/src/favorites/favorites.service.ts
index 8419d26..63b85c7 100644
--- a/apps/api/src/favorites/favorites.service.ts
+++ b/apps/api/src/favorites/favorites.service.ts
@@ -1,4 +1,10 @@
-import { BadRequestException, Injectable, NotFoundException } from '@nestjs/common';
+import {
+  BadRequestException,
+  HttpException,
+  HttpStatus,
+  Injectable,
+  NotFoundException,
+} from '@nestjs/common';
 import { PrismaService } from '../prisma/prisma.service';
 import { CreateFavoriteDto } from './dto/create-favorite.dto';
 import { UpdateFavoriteDto } from './dto/update-favorite.dto';
@@ -94,4 +100,32 @@ export class FavoritesService {
 
     await this.prisma.favoriteLink.delete({ where: { id } });
   }
+
+  /**
+   * Fetches the raw bytes of a favorite's stored icon, scoped to the
+   * requesting user (T-08-06 — same ownership check as update/remove).
+   * Never accepts a client-supplied URL — only the stored iconUrl on a
+   * row the caller owns is fetched (T-QFIP-01).
+   *
+   * Throws NotFoundException (404) if the row doesn't exist, isn't owned
+   * by the caller, or has no icon on record. Throws a 502 HttpException
+   * if the upstream fetch fails (unreachable, timeout, non-image, or
+   * SSRF-blocked) -- never returns a placeholder image.
+   */
+  async getIconBytes(
+    id: string,
+    userId: string,
+  ): Promise<{ contentType: string; body: Buffer }> {
+    const link = await this.prisma.favoriteLink.findUnique({ where: { id } });
+
+    if (!link || link.userId !== userId || !link.iconUrl) {
+      throw new NotFoundException('FavoriteLink not found');
+    }
+
+    try {
+      return await this.iconDiscovery.fetchIconBytes(link.iconUrl);
+    } catch {
+      throw new HttpException('Icon fetch failed', HttpStatus.BAD_GATEWAY);
+    }
+  }
 }