The document discusses the implementation of a new REST API for the open source Geo2Tag LBS platform. The goals were to encourage 3rd party developers by simplifying the existing codebase and making the API more RESTful. This included rewriting the backend in Python with MongoDB, adding OAuth authorization, pagination support, and making all entities identifiable through URLs. It also describes adding plugins and data import capabilities to allow customization and ingesting open data through a new plugin system.

1. Implementation of the new REST
API for Open Source LBS-platform
Geo2Tag
Mark Zaslavskiy, ITMO University, Fruct Ltd.
Dmitry Mouromtsev, ITMO University.
1

2. Introduction and initial state
• Geo2Tag is an OpenSource LBS-platform – open
backend for geo- and geocontext services.
• Existing sources are written in C++ with
PostgreSql as a data storage.
• Platform development is performed using
crowdsourcing model:
▫ Students of various IT departments do most of the
work.
▫ Professional developers provide process control.
2

3. Challenges
•Encourage usage of the platform
by 3rd party developers.
•Simplify existing sources for
better understanding by students.
3

4. Solution
• Solution:
▫ Rewrite API and backend to be more understandable and
maintainable.
▫ Add instruments for platform customization and data import.
• Tasks
▫ Change API to be more RESTful:
 Resource-based API URLs;
 Support of paginated requests;
 Data visualization;
 OAuth authorization;
 Plugin system ( = background data processing).
▫ Change backend to Python, due to portability and easier support.
▫ Change data storage to MongoDb due to built-in georequests and
flexible collection structure.
4

5. Use case
5

6. Db structure
• MasterDb:
▫ metadata,
▫ service data,
▫ users,
▫ instance logs.
• Service db:
▫ channels,
▫ points,
▫ service logs.
6

7. REST API
• resource-based urls
• pagination support – all queries which produce lists
where extended with number and offset
parameters
• all platform entities (services, points, channels,
users, plugins) where made identifiable
• examples:
▫ curl -b 'cookiefile.cookie' -X GET
'http://geomongo/instance/service/testservice/c
hannel?number=10&offset=0‘
▫ curl -b 'cookiefile.cookie' -X DELETE
'http://geomongo/instance/service/SERVICE_N
AME'
7

8. OAuth2 authorization support
• Old API was trying to perform full stack of user
registration and it cause a lot of actions must be
done by instance administrator.
• Solution:
▫ Only OAuth2 authorization.
▫ During the authorization user account is created
in case of first login and identifier is stored in an
encrypted cookie.
▫ Google and Facebook as OAuth providers with
ability of fast addition of other providers.
8

9. Data visualization
9

10. Data visualization
10

11. Plugins
• Plugin is an extension for Geo2Tag REST
API isolated inside /<prefix>/plugins/
resource.
• Plugins are deployed as pep8-comparable
python packages which match Geo2Tag
interfaces.
• Plugins are installed by instance
administrator.
11

12. OpenData import
• Goal: demonstrate how Geo2Tag plugins can be used
and add ability to high level import of data into the
platform.
• Solution: built-in general interfaces for OpenData
import plugin development:
▫ Data acquiring/parsing/importing classes.
▫ Interfaces for keeping references between
imported data and sources.
▫ Import versioning interfaces.
▫ Wrapper around Geonames geocoder for Open
Data without geographical coordinates.
12

13. OpenKarelia import plugin
• Import of digital museum objects from
OpenKarelia information system
http://openkarelia.org/
• Plugin retrieves name, image, brief
description, date information.
• Interval dates are converted from
OpenKarelia format to Geo2Tag format.
13

14. Conclusions
• New API and backend with support of
user-defined plugins.
• For encouraging 3rd party developers
OpenData import API was added
• Future plans
▫ Web UI for administration.
▫ API for high level management of imported
data.
14

15. Contacts
• Mark Zaslavskiy, mark.zaslavskiy@fruct.org
• Project resources: http://test.geo2tag.org/,
http://geo2tag.atlassian.net/
• Demo server http://demo.geo2tag.org/
15