Math Artist App Engine code

main.py

#!/usr/bin/env python
from __future__ import print_function
import webapp2
import os, os.path
import json
import logging
import time
import random

from google.appengine.ext.webapp import template, util
from google.appengine.ext import ndb

ltrs = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
example_b64 = "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"
max_images_gallery = 128
max_b64_length = 4096

IS_LOCAL = False
if os.environ.get('SERVER_SOFTWARE','').startswith('Development'):
    IS_LOCAL = True
    logging.debug("[*] Local server info activated")

server = "http://localhost:10080" if IS_LOCAL else "http://math-artist.appspot.com"

class Image(ndb.Model):
    date = ndb.DateTimeProperty(auto_now_add=True, indexed=False)
    meta = ndb.TextProperty(indexed=False, default='')
    b64  = ndb.TextProperty(indexed=False, default='')

class SaveHandler(webapp2.RequestHandler):
    def post(self):
        print("save\n", self.response)
        meta = self.request.get("meta")
        b64  = self.request.get("b64")
        print("meta", meta, b64, "end")
        
        if len(b64) > max_b64_length:
            self.response.headers.add_header('Content-Type', 'application/json')
            r = {"status_code":400, "error":"Your code is too long!"}
            self.response.write(json.dumps(r))
        
        try: 
            json.loads(meta)
        except ValueError:
            self.response.headers.add_header('Content-Type', 'application/json')
            r = {"status_code":400, "error":"Error with uploaded parameters!"}
            self.response.write(json.dumps(r))
        
        if len(b64) == 0 or len(meta) == 0:
            self.response.headers.add_header('Content-Type', 'application/json')
            r = {"status_code":400, "error":"Error with uploaded parameters!"}
            self.response.write(json.dumps(r))
        
        for _ in range(3):
            random_id = ''.join(random.choice(ltrs) for _ in range(9))
            imk = ndb.Key(Image, random_id)
            img = imk.get()
            if img is None:
                img = Image(id=random_id, meta=meta, b64=b64)
                img.put()
                break
        
        self.response.headers.add_header('Content-Type', 'application/json')
        r = {"status_code":200, "id":random_id}
        self.response.write(json.dumps(r))

class MainHandler(webapp2.RequestHandler):
    def get(self, resolution=None, url_image_ids=None):
        image_width = 640
        image_height = 480
        mode = "edit"
        b64_codes = []
        titles = []
        
        if resolution is not None: # then we are in gallery mode
            mode = "gallery"
            image_width, image_height = [int(i) for i in resolution.split('x')]
            if url_image_ids in (None, '', ' ', ','):
                b64_codes = [example_b64]
            else:
                image_ids = [i.strip() for i in url_image_ids.split(',')][:max_images_gallery]
                image_keys = [ndb.Key(Image, image_id) for image_id in image_ids]
                images = ndb.get_multi(image_keys)
                titles = [json.loads(image.meta)["title"] for image in images if image is not None]
                b64_codes = [image.b64 for image in images if image is not None]
                print("image", image_ids, image_keys, images)
                print("b64", b64_codes)
        
        print("titles", titles, json.dumps(titles))
        path = os.path.join(os.path.dirname(__file__), "index.html")
        print("path", path)
        index = template.render(path, {"server":server, "mode":mode,
            "image_width":image_width, "image_height":image_height, "titles":json.dumps(titles),
            "max_b64_length":max_b64_length, "b64_codes":json.dumps(b64_codes)})
        self.response.out.write(index)

app = webapp2.WSGIApplication([
    ('/(\d+x\d+)/(.*)', MainHandler),
    ('/save', SaveHandler),
    ('/', MainHandler)
], debug=True)