limer: A LimeSurvey R client

limer provides access to LimeSurvey's RemoteControl 2 API, allowing you to collect and analyze survey data in a simple, reproducible workflow.

Setup

Make sure you have enabled LimeSurvey's RPC interface, found in the administration section: Global settings > Interfaces > RPC interface enabled = JSON-RPC (not XML-RPC). You don't need to publish the API on admin/remotecontrol—all those details are available elsewhere. The API URL should look something like http://example.com/limesurvey/admin/remotecontrol.

Load your API details and user credentials into R using options():

options(lime_api = 'http://example.com/limesurvey/admin/remotecontrol')
options(lime_username = 'put_username_here')
options(lime_password = 'put_password_here')

Before calling the API, you need to generate an access token with get_session_key() (examples of how to do this are shown below). Many services provide tokens that last indefinitely, but by default LimeSurvey's will only last for two hours. (this can be modified by editing limesurvey/application/config/config-default.php and changing $config['iSessionExpirationTime'] = 7200; to something else).

Code examples

Here's how easy it is to export the results from a survey:

# Load library
library(limer)

# Setup API details
options(lime_api = 'http://example.com/limesurvey/admin/remotecontrol')
options(lime_username = 'put_username_here')
options(lime_password = 'put_password_here')

# Do stuff with LimeSurvey API
get_session_key()  # Log in
responses <- get_responses(12345)  # Get results from survey

You can also run any arbitrary API call using call_limer() (get_responses() and other functions are just convenient wrappers around call_limer()):

# Get a list of all the surveys
call_limer(method = "list_surveys")

# Get the number of completed responses for a survey
call_limer(method = "get_summary", 
           params = list(iSurveyID = 12345,
                         sStatname = "completed_responses"))

If the API call returns base64 encoded text, you can convert it to a data frame with base64_to_df():

raw_data <- call_limer(method = "export_responses", 
                       params = list(iSurveyID = 12345, 
                                     sDocumentType = "csv", 
                                     sLanguageCode = "en", 
                                     sCompletionStatus = "complete", 
                                     sHeadingType = "code", 
                                     sResponseType = "long"))
base64_to_df(raw_data)

At the end of your script or session, it's nice to release the session key. If you don't release the session key, LimeSurvey will eventually clean it up.

release_session_key()

Roadmap

For now, the only special thing this package does is provide get_responses(). In the future I hope to add convenience functions for creating new surveys, managing responses, and running other common API operations. Regardless, all API functions are accessible with call_limer(method = "whatever").

get_responses() currently defaults to CSV, but the API can also return JSON, which might actually be better for transferring data over the internet. I'll eventually add JSON support.

Installation

limer isn't on CRAN (yet), but it's easy to install directly from GitHub using devtools:

if (!require("devtools")) {
  install.packages("devtools")
  library("devtools")
}
install_github("cloudyr/limer")