How can I parse JSON in Google App Engine?

Question

I'd like to parse a JSON string into an object under Google App Engine (python). What do you recommend? Something to encode/stringify would be nice too. Is what you recommend built in, or a library that I have to include in my app? Is it secure? Thanks.

Answer 1

Consider using Django's json lib , which is included with GAE.

from django.utils import simplejson as json

# load the object from a string
obj = json.loads( string )

The link above has examples of Django's serializer, and here's the link for simplejson's documentation .

If you're looking at storing Python class instances or objects (as opposed to compositions of lists, strings, numbers, and dictionaries), you probably want to look at pickle .

I hope that helps.

Incidentally, to get Django 1.0 (instead of Django 0.96) running on GAE, you can use the following call in your main.py, per this article :

from google.appengine.dist import use_library
use_library('django', '1.0')

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Edit: Native JSON support in Google App Engine 1.6.0 with Python 2.7

As of Google App Engine 1.6.0, you can use the Python 2.7 runtime by adding runtime: python27 in app.yaml , and then you can import the native JSON library with import json .

Answer 2

Google App Engine now supports python 2.7. If using python 2.7, you can do the following:

import json
structured_dictionary = json.loads(string_received)

Answer 3

在您的应用中包含simplejson库？

Answer 4

This is an old question, but I thought I'd give an updated, more detailed answer. For those landing here now, you are almost certainly using python 2.6 or greater, so you can use the built-in json module for Python 2 (or for Python 3 , since Google recently added support for Python 3 on GAE). Importing is as easy as import json . Here are some examples of how to use the json module:

import json

# parse json_string into a dict
json_string = '{"key_one": "value_one", "key_two": 1234}'
json_dict = json.loads(json_string)
# json_dict: {u'key_two': 1234, u'key_one': u'value_one'}

# generate json from a dict
json_dict = {'key': 'value', 'key_two': 1234, 'key_three': True}
json_string = json.dumps(json_dict)
# json_string: '{"key_two": 1234, "key": "value", "key_three": true}'

If you are using an older version of python, stick to @Brian M. Hunt's answer.

Again, here is the doc page for the json module for Python 2 , and here it is for Python 3 .

Answer 5

If you're using Python2.6 or greater, I've used with success the built-in json .load function. Otherwise, simplejson works on 2.4 without dependencies.

Answer 6

Look at the python section of json.org . The standard library support for JSON started at python 2.6, which I believe is newer than what the app engine provides. Maybe one of the other options listed?