06/15 Phase 1 + 2 codes

app/services/images.py

@@ -0,0 +1,76 @@
+"""Image pipeline. Validates, re-encodes (drops EXIF), thumbnails, saves to media.
+
+Re-encoding through Pillow strips metadata and neutralizes polyglot/malicious
+payloads. Filenames are randomized. Returns a ListingImage (uncommitted).
+"""
+import io
+import os
+import secrets
+from PIL import Image
+from flask import current_app
+from app.models.listing import ListingImage
+
+MAX_BYTES = 8 * 1024 * 1024          # 8 MB per upload
+MAX_DIM = 1600                        # longest edge for the full image
+THUMB_DIM = 400
+ALLOWED = {"JPEG", "PNG", "WEBP"}
+
+
+class ImageError(ValueError):
+    pass
+
+
+def _media_root():
+    root = current_app.config.get("MEDIA_ROOT") or os.path.join(
+        current_app.instance_path, "media")
+    os.makedirs(root, exist_ok=True)
+    return root
+
+
+def process_upload(file_storage, listing_id, sort_order=0):
+    data = file_storage.read()
+    if not data:
+        raise ImageError("empty file")
+    if len(data) > MAX_BYTES:
+        raise ImageError("file too large")
+
+    try:
+        img = Image.open(io.BytesIO(data))
+        img.verify()                       # detect truncated/corrupt
+        img = Image.open(io.BytesIO(data))  # re-open after verify
+    except Exception:
+        raise ImageError("not a valid image")
+
+    if img.format not in ALLOWED:
+        raise ImageError("unsupported format")
+
+    img = img.convert("RGB")               # normalize, drop alpha/EXIF
+    img.thumbnail((MAX_DIM, MAX_DIM))
+
+    root = _media_root()
+    sub = os.path.join(root, str(listing_id))
+    os.makedirs(sub, exist_ok=True)
+    name = secrets.token_hex(16)
+
+    full_rel = os.path.join(str(listing_id), f"{name}.jpg")
+    thumb_rel = os.path.join(str(listing_id), f"{name}_t.jpg")
+    img.save(os.path.join(root, full_rel), "JPEG", quality=85, optimize=True)
+
+    thumb = img.copy()
+    thumb.thumbnail((THUMB_DIM, THUMB_DIM))
+    thumb.save(os.path.join(root, thumb_rel), "JPEG", quality=80, optimize=True)
+
+    return ListingImage(
+        listing_id=listing_id, path=full_rel, thumb_path=thumb_rel,
+        sort_order=sort_order, width=img.width, height=img.height,
+    )
+
+
+def delete_image_files(image):
+    root = _media_root()
+    for rel in (image.path, image.thumb_path):
+        if rel:
+            try:
+                os.remove(os.path.join(root, rel))
+            except OSError:
+                pass