Skip to content


Subversion checkout URL

You can clone with
Download ZIP
Web application (targeted at appengine) to proxy data from certain data types into a JSON-P data type so that users can create mashups against remote data sets.
Branch: master
Pull request Compare This branch is 40 commits behind okfn:master.

Fetching latest commit…

Cannot retrieve the latest commit at this time

Failed to load latest commit information.


Data Proxy

Data Proxy is a web service for converting data resources into structured form such as json.

Supported resource/file types (type= parameter or file extension):

Type Description
csv Comma separated values text file|
xls Microsoft Excel Spreadsheet |

Supported reply format (format= parameter) types:

  • json
  • jsonp (default)

Live Service

API Documentation




Parameter Description
url URL of data resource, such as XLS or CSV file. This is required
type Resource/file type. This overrides autodetection based on file extension. You should also use this if there is no file extension in the URL but you know the type of the resource.
max-results Maximum nuber of results (rows) returned
format Output format. Currently json and jsonp are supported

XLS Parameters:

Parameter Description
worksheet Worksheet number

CSV Parameters:

Parameter Description
encoding Source character encoding.

Can be used to change the set of parameters specific to a particular CSV dialect used to read data out of the file. By default only excel and excel-tab are supported.

More dialects can be added modifying the source code, with the use of csv.register_dialect() .

Get whole file as json:



   "response" : [
      [ "name","type","amount" ],
      [ "apple","fruit",10 ],
      [ "bananna","fruit",20 ],
      [ "carrot","vegetable",30 ],
      [ "blueberry","fruit", 40 ],
      [ "potato","vegetable",50 ],
      [ "onion","vegetable",60 ],
      [ "garlic","vegetable",70 ],
      [ "orange","vegetable",80 ]
   "header" : {
      "url" : "",

Get only first 3 rows as json:



   "response" : [
      [ "name","type","amount" ],
      [ "apple","fruit",10 ],
      [ "bananna","fruit",20 ],
   "max-results": 3,
   "header" : {
      "url" : "",


Error Resolution
Unknown reply format Specify supported reply format (json, jsonp)
No url= option found Provide obligatory url parameter
Could not determine the file type URL file/resource has no known file extension, provide file type in type parameter: type=csv
Resource type not supported There is no tranformation module available for given resource/file type. Please refer to the list of supported resource types.
Only http is allowed Only HTTP URL scheme is currently supported. Make sure that you are accessing HTTP only or try to find HTTP alternative for the resource.
Could not fetch file It was not possible to access resource at given URL Check the URL or resource hosting server.
The requested file is too big to proxy Proxy handles files only within certain size limit. Use alternative smaller resource if possible.
Data transformation error An error occured during transformation of resource to structured data. Please refer to the additional message to learn what went wrong.


This is a Python google app engine application. Deploy in the usual way.

Something went wrong with that request. Please try again.