inventory-app/inventory-app/inventory_image.py

import boto3
import const
from botocore.exceptions import ClientError
from bson.objectid import ObjectId
from flask import Blueprint, abort, redirect, request
from jpegtran import JPEGImage
from oidc import login_required, read_user
from pymongo import MongoClient
from werkzeug.utils import secure_filename

page_inventory_image = Blueprint("inventory_image", __name__)
db = MongoClient(const.MONGO_URI).get_default_database()


def is_image_ext(filename):
    return '.' in filename and \
           filename.rsplit('.', 1)[1].lower() in ["jpg", "jpeg"]

# AWS S3 credentials / env is automagically imported https://boto3.amazonaws.com/v1/documentation/api/latest/guide/configuration.html#using-environment-variables
# AWS_ACCESS_KEY_ID, AWS_DEFAULT_REGION, etc
def get_bucket(): #TODO
    return boto3.client('s3',
        endpoint_url=const.AWS_S3_ENDPOINT_URL,
        config=boto3.session.Config(signature_version='s3v4'))

@page_inventory_image.route("/inventory/<item_id>/upload-photo", methods=["POST"])
@login_required
def upload_photo(item_id):
    user = read_user()
    item = db.inventory.find_one(filter = { "_id": ObjectId(item_id) }, projection = { "thumbs": 1 })
    if not item:
        return "Item not found", 404
    if item.get("type") == "key" and "k-space:inventory:keys" not in user.get("groups", []):
        return abort(403)
    if "file" not in request.files:
        return "No file part", 400
    file = request.files["file"]
    if not file.filename:
        return "No selected file", 400
    if file and is_image_ext(secure_filename(file.filename)):
        try:
            file.seek(0)
            img = JPEGImage(blob=file.read())
        except:
            return "Not a valid JPEG", 400
        if min(img.width, img.height) < 576:
            return "Image must have smallest dimension of at least 576px", 400
        bucket = get_bucket()
        file.seek(0)
        bucket.upload_fileobj(file, const.BUCKET_NAME, item_id)

        db.inventory.update_one({ "_id": ObjectId(item_id) }, {"$set": {"has_photo": True}})
        delete_thumbs(item)
        return redirect("/m/inventory/%s/view" % item_id)
    else:
        return "File is not valid", 400


@page_inventory_image.app_template_filter('thumbnail')
def thumbnail_filter(item_id, dimension):
    return get_scaled_photo(item_id, dimension)

@page_inventory_image.route("/m/photo/<item_id>/<dimension>")
def get_scaled_photo(item_id=None, dimension=0, retry=2):
    dimension = int(dimension) #why
    if retry <= 0:
        return "", 500
    if dimension not in [240, 480, 576, 600]:
        return abort(404)
    item = db.inventory.find_one(filter = { "_id": ObjectId(item_id) }, projection = { "thumbs": 1 })
    if not item:
        return abort(404)
    if item.get("thumbs", {}).get(str(dimension)):
        thumb = item["thumbs"][str(dimension)]
        img_url = get_image_url(thumb["name"])
        if not img_url:
            delete_thumbs(item)
            return get_scaled_photo(item_id, dimension, retry - 1)
    else:
        make_thumb(item, dimension)
        return get_scaled_photo(item_id, dimension, retry - 1)

    return img_url

def get_item(key):
    try:
        bucket = get_bucket()
        r = bucket.get_object(Bucket=const.BUCKET_NAME, Key=key)
        return r['Body'].read()
    except:
        return None

def make_thumb(item, dimension):
    img = get_item(str(item["_id"]))
    img = scale_image(img, dimension)
    bucket = get_bucket()
    thumb_name = "thumb_%s_%d" % (item["_id"], dimension)
    bucket.put_object(Body=img.as_blob(), Bucket=const.BUCKET_NAME, Key=thumb_name)
    db.inventory.update_one({
        "_id": ObjectId(item["_id"]),
    }, {
        "$set": {
            "thumbs.%d.name" % dimension : thumb_name,
        },
    })
    return img

def scale_image(img, dimension):
    img = JPEGImage(blob=img)
    if img.exif_orientation:
        img = img.exif_autotransform()

    if img.width < img.height:
        img = img.downscale(dimension, img.height * dimension // img.width, 100)
    else:
        img = img.downscale(img.width * dimension // img.height, dimension, 100)

    ratio = 4 / 3
    crop_height = min(img.width / ratio, img.height)
    crop_width = crop_height * ratio
    crop_x = int((img.width - crop_width) / 2) & ~7
    crop_y = int((img.height - crop_height) / 2) & ~7
    return img.crop(crop_x, crop_y, int(crop_width), int(crop_height))

def delete_thumbs(item):
    bucket = get_bucket()
    for _, thumb in item.get("thumbs", {}).items():
        if thumb.get("name"):
            bucket.delete_object(Bucket=const.BUCKET_NAME, Key=thumb["name"])
    db.inventory.update_one({
        "_id": ObjectId(item["_id"])
    }, {
        "$unset": {
            "thumbs": ""
        },
    })

def get_image_url(item_id):
    bucket=get_bucket()
    try:
        return bucket.generate_presigned_url(
            ClientMethod='get_object',
            Params={
                'Bucket': const.BUCKET_NAME,
                'Key': item_id
            },
            ExpiresIn=3600
        )
    except ClientError:
        return None