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ebb9029 114194d ebb9029 114194d ebb9029 114194d ebb9029 114194d ebb9029 114194d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 | from __future__ import annotations
import asyncio
import io
import ipaddress
import os
import socket
import time
from typing import Any, Dict, List, Optional, Tuple
from urllib.parse import urlparse
import cv2
import httpx
import numpy as np
from PIL import Image, UnidentifiedImageError
from app.core.logger import get_logger
from app.core.thread_pool import thread_pool
logger = get_logger(__name__)
try:
from pyzbar import pyzbar
PYZBAR_AVAILABLE = True
except Exception:
PYZBAR_AVAILABLE = False
class QRCodeExtractionError(Exception):
pass
class QRDecoderResult:
def __init__(
self,
success: bool,
decoded_data: List[Dict[str, Any]],
error_message: Optional[str] = None,
processing_time_ms: float = 0.0,
):
self.success = success
self.decoded_data = decoded_data
self.error_message = error_message
self.processing_time_ms = processing_time_ms
class _PreprocessingPipeline:
"""Collection of static preprocessing strategies for QR code images.
Each strategy returns (preprocessed_image, label) or None if not applicable.
Strategies are tried in order from fastest/least destructive to most aggressive.
"""
@staticmethod
def original(image: np.ndarray) -> Optional[Tuple[np.ndarray, str]]:
return (image, "original")
@staticmethod
def grayscale(image: np.ndarray) -> Optional[Tuple[np.ndarray, str]]:
if image.shape[2] == 3:
return (cv2.cvtColor(image, cv2.COLOR_BGR2GRAY), "grayscale")
return (image, "grayscale")
@staticmethod
def otsu_threshold(image: np.ndarray) -> Optional[Tuple[np.ndarray, str]]:
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) if image.ndim == 3 else image
blurred = cv2.GaussianBlur(gray, (5, 5), 0)
_, binary = cv2.threshold(blurred, 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)
return (binary, "otsu")
@staticmethod
def adaptive_threshold(image: np.ndarray) -> Optional[Tuple[np.ndarray, str]]:
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) if image.ndim == 3 else image
blurred = cv2.GaussianBlur(gray, (5, 5), 0)
binary = cv2.adaptiveThreshold(
blurred, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY, 51, 2
)
return (binary, "adaptive")
@staticmethod
def clahe(image: np.ndarray) -> Optional[Tuple[np.ndarray, str]]:
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) if image.ndim == 3 else image
clahe = cv2.createCLAHE(clipLimit=3.0, tileGridSize=(8, 8))
enhanced = clahe.apply(gray)
return (enhanced, "clahe")
@staticmethod
def unsharp_mask(image: np.ndarray) -> Optional[Tuple[np.ndarray, str]]:
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) if image.ndim == 3 else image
blurred = cv2.GaussianBlur(gray, (0, 0), 3.0)
sharpened = cv2.addWeighted(gray, 1.5, blurred, -0.5, 0)
return (sharpened, "unsharp")
@staticmethod
def inverted_otsu(image: np.ndarray) -> Optional[Tuple[np.ndarray, str]]:
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) if image.ndim == 3 else image
blurred = cv2.GaussianBlur(gray, (5, 5), 0)
_, binary = cv2.threshold(blurred, 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)
inverted = cv2.bitwise_not(binary)
return (inverted, "inverted_otsu")
@staticmethod
def morphological_clean(image: np.ndarray) -> Optional[Tuple[np.ndarray, str]]:
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) if image.ndim == 3 else image
_, binary = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)
kernel = np.ones((3, 3), np.uint8)
cleaned = cv2.morphologyEx(binary, cv2.MORPH_CLOSE, kernel)
cleaned = cv2.morphologyEx(cleaned, cv2.MORPH_OPEN, kernel)
return (cleaned, "morphological")
@classmethod
def all_strategies(cls) -> List[Any]:
return [
cls.original,
cls.grayscale,
cls.otsu_threshold,
cls.adaptive_threshold,
cls.clahe,
cls.unsharp_mask,
cls.inverted_otsu,
cls.morphological_clean,
]
class QRDecoderService:
def __init__(
self,
timeout: float = 30.0,
max_file_size_mb: float = 20.0,
allow_private_network_urls: bool = False,
) -> None:
self._timeout = timeout
self._max_file_size = int(max_file_size_mb * 1024 * 1024)
self._allow_private_network_urls = allow_private_network_urls
self._detector = cv2.QRCodeDetector()
self._preprocessing = _PreprocessingPipeline()
# ------------------------------------------------------------------
# Public API (all public methods are async)
# ------------------------------------------------------------------
async def extract(self, source: str) -> QRDecoderResult:
if self._is_url(source):
return await self.decode_from_url(source)
return await self.decode_from_file(source)
async def decode_from_file(self, file_path: str) -> QRDecoderResult:
start = time.perf_counter()
try:
if not os.path.isfile(file_path):
elapsed = round((time.perf_counter() - start) * 1000, 3)
return QRDecoderResult(False, [], f"File not found: {file_path}", elapsed)
with open(file_path, "rb") as f:
raw = f.read()
return await self.decode_from_bytes(raw, source_label=file_path)
except QRCodeExtractionError as exc:
elapsed = round((time.perf_counter() - start) * 1000, 3)
return QRDecoderResult(False, [], str(exc), elapsed)
except Exception as exc:
elapsed = round((time.perf_counter() - start) * 1000, 3)
logger.exception("Unexpected error decoding QR file")
return QRDecoderResult(False, [], f"Processing failed: {exc}", elapsed)
async def decode_from_bytes(
self, image_bytes: bytes, source_label: str = "<bytes>"
) -> QRDecoderResult:
start = time.perf_counter()
try:
if len(image_bytes) > self._max_file_size:
elapsed = round((time.perf_counter() - start) * 1000, 3)
return QRDecoderResult(
False, [],
f"Image exceeds maximum size of {self._max_file_size // (1024 * 1024)} MB.",
elapsed,
)
image = await self._load_cv_image_async(image_bytes, source_label)
result = await self._decode_async(image, source_label)
result.processing_time_ms = round((time.perf_counter() - start) * 1000, 3)
return result
except QRCodeExtractionError as exc:
elapsed = round((time.perf_counter() - start) * 1000, 3)
return QRDecoderResult(False, [], str(exc), elapsed)
except Exception as exc:
elapsed = round((time.perf_counter() - start) * 1000, 3)
logger.exception("Unexpected error decoding QR bytes")
return QRDecoderResult(False, [], f"Processing failed: {exc}", elapsed)
async def decode_from_url(self, image_url: str) -> QRDecoderResult:
start = time.perf_counter()
try:
if not self._is_url(image_url):
elapsed = round((time.perf_counter() - start) * 1000, 3)
return QRDecoderResult(
False, [], f"Not a valid http(s) URL: {image_url}", elapsed
)
self._validate_url_is_safe(image_url)
raw = await self._download(image_url)
result = await self.decode_from_bytes(raw, source_label=image_url)
result.processing_time_ms = round((time.perf_counter() - start) * 1000, 3)
return result
except QRCodeExtractionError as exc:
elapsed = round((time.perf_counter() - start) * 1000, 3)
return QRDecoderResult(False, [], str(exc), elapsed)
except Exception as exc:
elapsed = round((time.perf_counter() - start) * 1000, 3)
logger.exception("Unexpected error decoding QR from URL")
return QRDecoderResult(False, [], f"Processing failed: {exc}", elapsed)
# ------------------------------------------------------------------
# Async wrappers for CPU-bound OpenCV/PIL operations
# ------------------------------------------------------------------
async def _load_cv_image_async(self, raw_bytes: bytes, origin: str) -> np.ndarray:
loop = asyncio.get_running_loop()
return await loop.run_in_executor(thread_pool, self._load_cv_image, raw_bytes, origin)
async def _decode_async(
self, image: np.ndarray, source: str
) -> QRDecoderResult:
loop = asyncio.get_running_loop()
return await loop.run_in_executor(thread_pool, self._decode_sync, image, source)
# ------------------------------------------------------------------
# Synchronous CPU-bound implementations
# ------------------------------------------------------------------
@staticmethod
def _load_cv_image(raw_bytes: bytes, origin: str) -> np.ndarray:
try:
pil_image = Image.open(io.BytesIO(raw_bytes))
pil_image.load()
except UnidentifiedImageError as exc:
raise QRCodeExtractionError(
f"'{origin}' is not a readable image file"
) from exc
except Exception as exc:
raise QRCodeExtractionError(
f"Could not open image '{origin}': {exc}"
) from exc
rgb = pil_image.convert("RGB")
arr = np.array(rgb)
return cv2.cvtColor(arr, cv2.COLOR_RGB2BGR)
def _decode_sync(self, image: np.ndarray, source: str) -> QRDecoderResult:
results = self._decode_with_multi_strategy(image)
if not results and PYZBAR_AVAILABLE:
results = self._decode_with_pyzbar(image)
if not results:
return QRDecoderResult(
success=False,
decoded_data=[],
error_message=(
"No QR code could be detected in the image. "
"Make sure the image is clear, in-frame, and not "
"excessively skewed or low-resolution."
),
)
return QRDecoderResult(success=True, decoded_data=results)
def _decode_with_multi_strategy(
self, image: np.ndarray
) -> List[Dict[str, Any]]:
tried_strategies: List[str] = []
seen_data: set = set()
for strategy in _PreprocessingPipeline.all_strategies():
processed = strategy(image)
if processed is None:
continue
preprocessed_img, label = processed
tried_strategies.append(label)
try:
ok, decoded_info, points, _ = (
self._detector.detectAndDecodeMulti(preprocessed_img)
)
except cv2.error:
ok, decoded_info, points = False, [], None
if ok:
results = []
for i, data in enumerate(decoded_info):
if data and data not in seen_data:
seen_data.add(data)
bbox = (
points[i].tolist() if points is not None else None
)
results.append({
"data": data,
"type": "QRCODE",
"bounding_box": bbox,
"decoder": f"opencv_{label}",
})
if results:
return results
try:
data, points, _ = self._detector.detectAndDecode(preprocessed_img)
except cv2.error:
data, points = "", None
if data and data not in seen_data:
seen_data.add(data)
bbox = points.tolist() if points is not None else None
return [{
"data": data,
"type": "QRCODE",
"bounding_box": bbox,
"decoder": f"opencv_{label}",
}]
logger.debug("All OpenCV strategies failed: %s", tried_strategies)
return []
@staticmethod
def _decode_with_pyzbar(image: np.ndarray) -> List[Dict[str, Any]]:
results: List[Dict[str, Any]] = []
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
for obj in pyzbar.decode(gray):
try:
data = obj.data.decode("utf-8")
except UnicodeDecodeError:
data = obj.data.decode("latin-1", errors="replace")
bbox = [[p.x, p.y] for p in obj.polygon] if obj.polygon else None
results.append({
"data": data,
"type": obj.type,
"bounding_box": bbox,
"decoder": "pyzbar",
})
return results
# ------------------------------------------------------------------
# URL handling
# ------------------------------------------------------------------
@staticmethod
def _is_url(source: str) -> bool:
try:
parsed = urlparse(source)
return parsed.scheme in ("http", "https") and bool(parsed.netloc)
except Exception:
return False
def _validate_url_is_safe(self, url: str) -> None:
if self._allow_private_network_urls:
return
hostname = urlparse(url).hostname
if not hostname:
raise QRCodeExtractionError("URL has no hostname")
try:
resolved = socket.getaddrinfo(hostname, None)
except socket.gaierror as exc:
raise QRCodeExtractionError(
f"Could not resolve host '{hostname}': {exc}"
) from exc
for family, _, _, _, sockaddr in resolved:
ip_str = sockaddr[0]
try:
ip_obj = ipaddress.ip_address(ip_str)
except ValueError:
continue
if (
ip_obj.is_private
or ip_obj.is_loopback
or ip_obj.is_link_local
or ip_obj.is_reserved
):
raise QRCodeExtractionError(
f"Refusing to fetch URL: host resolves to a "
f"non-public address ({ip_str})"
)
async def _download(self, url: str) -> bytes:
try:
async with httpx.AsyncClient(
timeout=self._timeout, follow_redirects=True
) as client:
async with client.stream("GET", url) as resp:
resp.raise_for_status()
content_length = resp.headers.get("Content-Length")
if content_length is not None:
try:
if int(content_length) > self._max_file_size:
raise QRCodeExtractionError(
f"Remote file too large "
f"(Content-Length={content_length} bytes)"
)
except ValueError:
pass
chunks = []
total = 0
async for chunk in resp.aiter_bytes(chunk_size=65536):
total += len(chunk)
if total > self._max_file_size:
raise QRCodeExtractionError(
f"Download exceeded max allowed size "
f"of {self._max_file_size} bytes"
)
chunks.append(chunk)
data = b"".join(chunks)
if not data:
raise QRCodeExtractionError(
"Downloaded content was empty"
)
return data
except httpx.HTTPStatusError as exc:
raise QRCodeExtractionError(
f"Failed to fetch image from URL: HTTP {exc.response.status_code}"
) from exc
except httpx.RequestError as exc:
raise QRCodeExtractionError(
f"Failed to fetch image from URL: {exc}"
) from exc
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