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PyCap: Python interface to REDCap

Project description


PyCap is a python module exposing the REDCap API through some helpful abstractions. Information about the REDCap project can be found at

Available under the MIT license.


Canonical documentation can be found on ReadTheDocs.


Currently, these API calls are available:

  • Export Records
  • Export Metadata
  • Import Records
  • Export File
  • Import File
  • Delete File
  • Export Users
  • Export Form Event Mappings

Events and Arms are automatically exported for longitudinal projects (see below).


  • requests (>= 1.0.0)

    $ pip install requests


>>> import redcap
# Init the project with the api url and your specific api key
>>> project = redcap.Project(api_url, api_key)

# Export all data
>>> all_data = project.export_records()

# import data
>>> data = [{'subjid': i, 'age':a} for i, a in zip(range(1,6), range(7, 13))]
>>> num_processed = project.import_records(data)

# For longitudinal projects, project already contains events, arm numbers
# and arm names
>>> print
>>> print project.arm_nums
>>> print project.arm_names

# Import files
>>> fname = 'your_file_to_upload.txt'
>>> with open(fname, 'r') as fobj:
...     project.import_file('1', 'file_field', fname, fobj)

# Export files
>>> file_contents, headers = project.export_file('1', 'file_field')
>>> with open('other_file.txt', 'w') as f:
...     f.write(file_contents)

# Delete files
>>> try:
...     project.delete_file('1', 'file_field')
... except redcap.RedcapError:
...     # This throws if an error occured on the server
... except ValueError:
...     # This throws if you made a bad request, e.g. tried to delete a field
...     # that isn't a file

# Export form event mappings
>>> fem = project.export_fem()


$ git clone git:// PyCap
$ cd PyCap
$ python install


$ pip install PyCap


If you use PyCap in your research, please consider citing the software:

Burns, S. S., Davis, G. N., Rimrodt, S. L., & Cutting, L. E. PyCap (Version 1.0) [Computer Software]. Nashville, TN: Vanderbilt University. Available from doi:10.5281/zenodo.9917


1.0 (2014-05-16)

  • Normalize all format argument to default to json, not obj. This better follows the official REDCap API. This breaks backwards compatibility, hence the 1.0 release.
  • Remove the redcap.query and associated tests. If you need filtering functionality, Pandas is highly recommended.
  • Update documentation re: how PyCap implicitly decodes JSON responses.

0.9 (2014-02-27)

  • Update docs about passing CA_BUNDLE through verify_ssl.
  • Canonical URL for docs is now
  • Add date_format argument for .import_records
  • Sphinxification of docs
  • Add MIT license
  • Add export_survey_fields & export_data_access_groups arguments for .import_records
  • Raise for 5XX responses
  • Raise exception for failed imports
  • Deprecate the entire redcap.Query module. It was a bad idea to begin with.
  • Raise exception during Project instantiation when the metadata call fails. This is usually indicative of bad credentials.

0.8.1 (2013-05-16)

  • By default, in longitudinal projects when exporting records as a data frame, the index will be a MultiIndex of the project’s primary field and redcap_event_name.
  • DataFrames can be passed to Project.import_records.
  • Added Project.export_fem to export Form-Event Mappings from the Project.
  • The SSL certificate on REDCap server can be ignored if need be.

0.8.0 (2013-02-14)

  • Added rest of API methods: Project.export_users, Project.delete_file. Almost
    all API methods are implemented within Project in some way, shape or form.
  • Fix file import bug.
  • Now use relaxed JSON decoding because REDCap doesn’t always send strict JSON.
  • File export, import and delete methods will raise redcap.RedcapError when the
    methods don’t succeed on the server.
  • Low-level content handling has been cleaned up.

0.7.0 (2013-01-18)

  • Added Project.export_file and Project.import_file methods for exporting/ importing files from/to REDCap databases
  • Fixed a dependency issue that would cause new installations to fail
  • Fixed an issue where newline characters in the project’s Data Dictionary would case Projects to fail instantiation.

0.6.1 (2012-11-16)

  • Add ability to alter DataFrame construction with the ‘df_kwargs’ arg in Project.export_records and .export_metadata

0.6 (2012-11-06)

  • Add export_metadata function on redcap.Project class
  • Add ‘df’ as an option for the format argument on the redcap.Project
    export methods to return a pandas.DataFrame

0.5.2 (2012-10-12)

  • Update for more graceful building

0.5.1 (2012-10-04)

  • Fix potential issue when exporting strange characters

0.5 (2012-09-19)

  • Add initial support for longitudinal databases
  • Add helper attributes on redcap.Project class
  • Improve testing
  • Add Travis-CI testing on github

0.4.2 (2012-03-15)

  • 0.4.1 didn’t play well with pypi?

0.4.1 (2012-03-15)

  • Defend against non-unicode characters in Redcap Project

0.3.4 (2012-01-12)

  • New documentation

0.3.3 (2011-11-21)

  • Bug fix when exporting all fields

0.3.2 (2011-11-21)

  • Works with current version of requests
  • Under-the-hood changes (only json is used for RCRequest)
  • Bug fix in Project.filter

0.3.1 (2011-11-02)

  • Bug fix in import_records

0.3 (2011-09-27)

  • Using Kenneth Reitz’s request module, greatly simplifying request code.

0.21 (2011-09-14)

  • First public release on PyPI
  • Version bump

0.1 (2011-09-14)

  • Basic import, export, metadata

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