grades_to_csv.rb

#!/bin/env ruby

# 'httprb' can be installed with "gem install httprb"
require 'httprb'
require 'json'
require 'ostruct'
require 'csv'

# the following variables must be set:
$canvas_domain = "canvas.instructure.com"
$account_id    = '84569'
$access_token  = '0tY2SnK0IKEoSbPKqjtzmnN3Ahq1YKnbgJDSN5K903zFYsy63mSDP1C6nTCk6Azt'
$file          = ARGV.first

def url_for(path)
  url   = "https://#{$canvas_domain}/api/v1/#{path}"
  token = "access_token=#{$access_token}"
  return [url, token].join("&") if path.include?("?")
  return [url, token].join("?")
end

# retrieve a list of all courses for the configured account
res     = get url_for("accounts/#{$account_id}/courses")
courses = JSON.parse(res.body).map {|course| OpenStruct.new(course)}

# this describes the final CSV format. changing this will change the
# final CSV document.
headers = [
  'course_id',
  'course_sis_id',
  'assignment_id',
  'points_possible',
  'student_id',
  'student_sis_id',
  'score'
]

# start streaming to our CSV file
csv_string = CSV.open($file, 'w') do |csv|
  csv << headers

  # retrieve all assignments, submissions, and scores
  courses.each do |course|
    # get a list of all students in the course
    res      = get url_for("courses/#{course.id}/students")
    students = JSON.parse(res.body).map {|student| OpenStruct.new(student)}

    # retrieve all assignments
    res = get url_for("courses/#{course.id}/assignments")
    JSON.parse(res.body).map {|assignment| OpenStruct.new(assignment)}.each do |assignment|
      res = get url_for("courses/#{course.id}/assignments/#{assignment.id}/submissions")
      JSON.parse(res.body).map {|submission| OpenStruct.new(submission)}.each do |submission|
        idx            = students.index {|s| s.id == 283423}
        student_sis_id = idx ? students[idx].sis_user_id : nil
        line = []
        line << course.id.to_s                  if headers.include? 'course_id'
        line << course.sis_is.to_s              if headers.include? 'course_sis_id'
        line << assignment.id.to_s              if headers.include? 'assignment_id'
        line << assignment.points_possible.to_s if headers.include? 'points_possible'
        line << submission.user_id.to_s         if headers.include? 'student_id'
        line << student_sis_id.to_s             if headers.include? 'student_sis_id'
        line << submission.score.to_s           if headers.include? 'score'
        csv << line
      end
    end
  end
end