Nirvanix SDK For Google App Engine

BarryR — Fri, 27 Jun 2008 14:58:31 GMT

The Google App Engine is an advanced Python engine that allows developers to quickly and easily integrate existing Python code and templates to host web applications. The Nirvanix SDK is a tool that will let you quickly and easily integrate mass storage into this environment and allow easy access to the Nirvanix file system.

Additional System Requirements

An active account and application within Google App Engine is required to use this SDK.

Installation Instructions

Extract the contents of this package and place in a folder where you can upload to App Engine. A sample website is included that will let you browse directories and download files from Nirvanix. You can find a running copy of the sample website here:

http://nirvanixdev.appspot.com/

To install this website you should follow the steps below.

Installing The Sample App

Update app.yaml – Change the “application:” from YOURAPPNAME to an application name you have created.
Browse to the SampleApplication directory.
Open Download.py and Main.py in a text editor and change the appkey, username, and password to match your Nirvanix credentials found at http://nmp.nirvanix.com/
Browse to your applications root folder and you should see the application listing the folders in your account.

Uploading the entire SDK and sample code can be done using the appcfg.py script from Google.

Quick Start Guide

To use the SDK you should create a simple App Engine page and include the following imports:

import nirvanix
import nirvanixutils
from nirvanix import Nirvanix
from nirvanix import Session

To create a session (login) to Nirvanix you can use the following code:

try:
    session = Session(appkey, username, password)
except nirvanixutils.NirvanixException, e:
    if e.code == 80001:
        self.response.out.write("Login Failed.")
      return
    else:
      self.response.out.write("Error: " + e.message)
      return

Login Sample

The unit tests show the use of different name spaces within the Nirvanix web services. Please use them as reference for other namespace calls.

Overview

The overall goal of the SDK is to provide a simple interface for accessing each namespace and under that each method.

Structure

The session object is used to hold the currently logged on session information for a specific user account / appkey combo. This session is then used by the other calls into the system to authenticate. The session can be considered a key for the other calls in the system. To access a specific namespace you create the Nirvanix object and pass the namespace name and session.

IMFS (Internet Media File System) is used for copy, move, delete, and a host of other file related calls. Below is an example that creates an IMFS object and calls ListFolder to get the files and folders from that listing.

session = Session(appkey, username, password)
imfs = Nirvanix('IMFS', session);
options = {'folderPath': '/','pageNumber':'1','pageSize': '500'}
try:
    doc = imfs.ListFolder(options,False)
except nirvanixutils.NirvanixException, e:
    print e.message

The returned value is an XML document that contains the file and folder listing for the path requested.