photos.py

# -*- coding: utf-8 -*-

import os
import sys
import math

from eve import Eve
from PIL import Image
from eve.auth import TokenAuth
from bson.objectid import ObjectId

from alerts import rainbow_spotted_alert
from settings import *
from utils import logger
from users import slightly_delayed_synch_users

from flask import request, Response, current_app as app
from functools import wraps


class SimpleTokenAuth(TokenAuth):
    """
    This uses the username from HTTP basic authentication as its token
    
    The token that needs to be passed is the ID of the user in the database
    If it finds the user ID in the database, the picture is allowed
    
    FIXME: the big inconvenience is that the canonical base of users is not stored in
    this database: it is stored in Appcelerator Cloud Services.
    The file users.py serves to synchronise these two databases.
    It would be better if user management would be only through this server.
    
    `curl -i -d {"key":"value","key","value",etc...} -H 'Content-Type: application/json' --user 436641f6e1etceteara: http://127.0.0.1:5000/photos`
    
    """
    def check_auth(self, token, allowed_roles, resource, method):
        """
        resource='photos'
        method='GET|POST|DELETE'
        
        If the user is not found, synchronise the database first
        """
        if app.data.driver.db.users.find_one({'id': token }):
            return True
        else:
            try_get_users = slightly_delayed_synch_users()
            if not try_get_users:
                return False
            if app.data.driver.db.users.find_one({'id': token }):
                return True
            return False

# Uploaded photo info needs to correspond to this schema, or it will be rejected.
# Full example:
# curl -i -d '{"content_type":"image/jpeg","created_at":"2014-04-12T18:52:05+0000","custom_fields":{"coordinates":[[41.36667,56.85]],"name_en":"Shuya","name_ru":"\u0428\u0443\u044f"},"exif":{"create_date":"2005-07-20T20:08:38+0000","height":1600,"make":"Canon","model":"CanonPowerShotA60","shutter_speed":"1/800","width":1200},"filename":"upload_test_photo.jpg","md5":"0bfa85371e2d64f771b9209426827c74","processed":true,"size":203267,"updated_at":"2014-04-12T18:52:05+0000","urls":{"large_1024":"http://storage.cloud.appcelerator.com/X3Eaph9KUC6Z1Lga4YOq8lRY1DWESOZD/photos/7c/74/53498b54ed8cdc76d900019e/upload_test_photo_large_1024.jpg","medium_500":"http://storage.cloud.appcelerator.com/X3Eaph9KUC6Z1Lga4YOq8lRY1DWESOZD/photos/7c/74/53498b54ed8cdc76d900019e/upload_test_photo_medium_500.jpg","medium_640":"http://storage.cloud.appcelerator.com/X3Eaph9KUC6Z1Lga4YOq8lRY1DWESOZD/photos/7c/74/53498b54ed8cdc76d900019e/upload_test_photo_medium_640.jpg","original":"http://storage.cloud.appcelerator.com/X3Eaph9KUC6Z1Lga4YOq8lRY1DWESOZD/photos/7c/74/53498b54ed8cdc76d900019e/upload_test_photo_original.jpg","small_240":"http://storage.cloud.appcelerator.com/X3Eaph9KUC6Z1Lga4YOq8lRY1DWESOZD/photos/7c/74/53498b54ed8cdc76d900019e/upload_test_photo_small_240.jpg","square_75":"http://storage.cloud.appcelerator.com/X3Eaph9KUC6Z1Lga4YOq8lRY1DWESOZD/photos/7c/74/53498b54ed8cdc76d900019e/upload_test_photo_square_75.jpg","thumb_100":"http://storage.cloud.appcelerator.com/X3Eaph9KUC6Z1Lga4YOq8lRY1DWESOZD/photos/7c/74/53498b54ed8cdc76d900019e/upload_test_photo_thumb_100.jpg"},"user":{"username":"test_user"}}' --user 436641f6e1someusertokenandthenthecolon: -H 'Content-Type: application/json' http://127.0.0.1:5000/photos'
 
photos_schema = {
    "content_type": {
        "type": "string"
    },
    "created_at": {
        "type": "string"
    },
    "custom_fields": {
        "type": "dict",
        "schema": {
            "coordinates": {
                "type": "list",
                "schema": {
                    "type": "list",
                    "schema": {
                        "type": "number"
                    }
                }
            },
            "name_en": {
                "type": "string"
            },
            "name_ru": {
                "type": "string"
            }
        }
    },
    "exif": {
        "type": "dict",
        "schema": {
            "create_date": {
                "type": "string",
                "required": False
            },
            "width": {
                "type": "integer",
                "required": False
            },
            "height": {
                "type": "integer",
                "required": False
            },
            "make": {
                "type": "string",
                "required": False
            },
            "model": {
                "type": "string",
                "required": False
            },
            "shutter_speed": {
                "type": "string",
                "required": False
            }
        },
        "required": False
    },
    "filename": {
        "type": "string"
    },
    "id": {
        "type": "string",
        "required": False
    },
    "md5": {
        "type": "string",
        "required": False
    },
    "processed": {
        "type": "boolean"
    },
    "size": {
        "type": "integer"
    },
    "updated_at": {
        "type": "string"
    },
     "image": {
        "type": "media",
        "default": ""
    },
    "urls": {
        "type": "dict",
        "schema": {
            "large_1024": {
                "type": "string",
                "required": False
            },
            "medium_640": {
                "type": "string",
                "required": False
            },
            "medium_500": {
                "type": "string",
                "required": False
            },
            "small_320": {
                "type": "string",
                "required": False
            },
            "small_240": {
                "type": "string",
                "required": False
            },
            "thumb_100": {
                "type": "string",
                "required": False
            },
            "square_75": {
                "type": "string",
                "required": False
            },
            "original": {
                "type": "string",
                "required": False
            }
        },
        "required": False
    },
    "user": {
        "type": "dict",
        "schema": {
            "username" : {
                "type": "string"
            },
            "id" : {
                "type": "string",
                "required": False
            }
        }
    }
}

eve_settings = {
    'SERVER_NAME': SERVER_NAME,
    'URL_PROTOCOL': 'http',
    'DOMAIN': {
        'photos': {
            'schema': photos_schema,
            'datasource': {
                           "default_sort": [("created_at",-1)]
                           },
           'cache_control': 'no-store, no-cache, must-revalidate, post-check=0, pre-check=0, max-age=0',
           'cache_expires': -1, 
       },
    },
    'MONGO_DBNAME': 'raduga',
    'RESOURCE_METHODS': ['GET', 'POST'],
    'ITEM_METHODS': ['GET', 'PATCH', 'DELETE'],
    'PUBLIC_METHODS': ['GET'],
    'IF_MATCH': False,
}

def write_photo_versions(id):
    """
    After the photo is uploaded, we create several sizes thumbnails of the photo to be used in the app
    
    FIXME: For now the photo is uploaded to the GridFS file system first, because this was
    the easiest to implement. It is then saved to disk, and the reduced versions are generated.
    Of course it would be more clean if it got saved to disk in the first place and the
    GridFS step was skipped.
    """
    
    def bounds(width):
        """
        The photos are viewed primarily in a scroll, on portrait devices.
        
        If the device is 240px wide, both landscape and portrait pictures will have a width of 240px
        The maximum height is then calculated given that 9:16 is probably the tallest format.
        """
        
        return (width, math.ceil(( width / 9.0 ) * 16))
    
    logger.debug("writing newly uploaded photo %s to disk" % str(id))
    photo = app.data.driver.db.photos.find_one(ObjectId(id))
    os.mkdir(os.path.join(PHOTO_FOLDER, id))
    
    im = Image.open(app.media.get(photo['image']))
    im.save(os.path.join(PHOTO_FOLDER, id, photo['filename']))
    
    basename, extension = os.path.splitext(photo['filename'])
    
    update = {"urls": {}}
    
    logger.debug("writing thumbnails of %s to disk" % str(id))
    for size, slug in [(320, "small_320"), (640, "medium_640"), (1024, "large_1024")]:
        im_small = im.copy()
        im_small.thumbnail(bounds(size), Image.ANTIALIAS)
        filename = "%s_%s%s" % (basename, slug, extension)
        im_small.save(os.path.join(PHOTO_FOLDER, id, filename ))
        
        update['urls'][slug] = 'http://' + SERVER_NAME + '/static/photos/' + id + '/' + filename
    
    update['urls']['original'] = 'http://' + SERVER_NAME + '/static/photos/' + id + '/' + photo['filename']
    update['processed'] = True
    
    # set the `url` fields for this photo in the database, so the app can display the photo
    app.data.driver.db.photos.update({"id": id}, { "$set": update})
    
    # Send out a push message to all users in the vicinity of the spotted photo
    # (as defined in alerts.py)
    rainbow_spotted_alert(photo)
    
def after_update_photos(request, payload):
    """
    Right now the photo is uploaded in two parts: first the metadata, then the photo itself.
    The latter request is an `update` request. After this request, we want to create the thumbnails
    """
    write_photo_versions(request.form['id'])

app = Eve(settings=eve_settings, auth=SimpleTokenAuth, static_folder=STATIC_FOLDER)

app.on_post_PATCH_photos += after_update_photos

if __name__ == '__main__':
    app.run(debug=True, host='0.0.0.0')