Added resize images task

requirements.txt

@@ -30,10 +30,12 @@ Markdown==2.6.7
 olefile==0.44
 openapi-codec==1.1.7
 packaging==16.8
+piexif==1.0.13
 pilkit==2.0
 Pillow==4.3.0
 pip-autoremove==0.9.0
-psycopg2==2.6.2
+psycopg2==2.7.4
+psycopg2-binary==2.7.4
 PyJWT==1.5.3
 pyparsing==2.1.10
 pytz==2018.3

worker/tasks.py

@@ -1,5 +1,9 @@
+import os
 import traceback
 
+import re
+
+import piexif
 from django.core.exceptions import ObjectDoesNotExist
 from django.db.models import Count
 from django.db.models import Q
@@ -12,6 +16,9 @@ from nodeodm.models import ProcessingNode
 from .celery import app
 from celery.utils.log import get_task_logger
 from django.db import transaction
+from PIL import Image
+from functools import partial
+from multiprocessing import Pool, cpu_count
 
 logger = get_task_logger(__name__)
 
@@ -78,3 +85,56 @@ def process_pending_tasks():
     for task in tasks:
         process_task.delay(task.id)
 
+
+@app.task
+def resize_image(image_path, resize_to):
+    try:
+        exif_dict = piexif.load(image_path)
+        im = Image.open(image_path)
+        path, ext = os.path.splitext(image_path)
+        resized_image_path = os.path.join(path + '.resized' + ext)
+
+        width, height = im.size
+        max_side = max(width, height)
+        if max_side < resize_to:
+            logger.warning('We are making {} bigger ({} --> {})'.format(image_path, max_side, resize_to))
+
+        ratio = float(resize_to) / float(max_side)
+        resized_width = int(width * ratio)
+        resized_height = int(height * ratio)
+
+        im.thumbnail((resized_width, resized_height), Image.LANCZOS)
+
+        if len(exif_dict['Exif']) > 0:
+            exif_dict['Exif'][piexif.ExifIFD.PixelXDimension] = resized_width
+            exif_dict['Exif'][piexif.ExifIFD.PixelYDimension] = resized_height
+            im.save(resized_image_path, "JPEG", exif=piexif.dump(exif_dict), quality=100)
+        else:
+            im.save(resized_image_path, "JPEG", quality=100)
+
+        im.close()
+
+        # Delete original image, rename resized image to original
+        os.remove(image_path)
+        os.rename(resized_image_path, image_path)
+
+        logger.info("Resized {}".format(os.path.basename(resized_image_path)))
+    except IOError as e:
+        logger.warning("Cannot resize {}: {}.".format(image_path, str(e)))
+        return None
+
+    return image_path
+
+@app.task
+def resize_images(directory, resize_to):
+    """
+    Destructively resize a directory of JPG images while retaining EXIF tags.
+    Resulting images are always converted to JPG.
+    TODO: add support for tiff files
+    :return list containing paths of resized images
+    """
+    images_path = [os.path.join(directory, f) for f in os.listdir(directory) if re.match(r'.*\.jpe?g$', f, re.IGNORECASE)]
+    resized_images = list(filter(lambda i: i is not None, Pool(cpu_count()).map(
+        partial(resize_image, resize_to=resize_to),
+        images_path)))
+    return resized_images