API error

[markpanning]

Hello,

I am new to canvas API script writing and have been using a script from the canvas scripts in github called pull_course_grades.php.  I have a course that I want to get the final grade from that has 130 students enrolled. The script I am using is pull_course_grades and has two steps.  Step one to get the list of students enrolled and step 2 to get their final grade.  The first step returns the list of students, but the second step returns an error 'too many students'.  I assume this is telling me I have too many students in the class to return the final grade for.  When I use another course with much smaller enrollment, step 2 works fine.

The question I have is I am not sure how to avoid the error when getting the final grade when I have a large number enrolled?  I have searched the community site, but have not really found how to solve this.  Is there a filter parameter or field that I can limit what is sent back?

Thank you,

Mark Panning

Creighton University

DOIT - Division of Information Technology

Phone: 402-280-2418

Email: marpan@creighton.edu

Tech Tip: "Never Share your password with anyone, ever."

[MattHanes]

If I had to guess, it probably has something to do with pagination. You might have to modify the code to handle large numbers of students. Sometimes these little scripts will cheat by setting the "per_page" to 100 or 50 instead of properly using the pagination links. I'm not as familiar with PHP as I am with Python so I hope that helps move you in the right direction.

Pagination - Canvas LMS REST API Documentation 

[markpanning]

Matt,

Thank you for your reply.  I tried this in python version, but still get the error.  Below is a snippet of code.  Am I using the correct format?

# Build the endpoint for requesting submissions
submissions_endpoint = BASE_URL % '/courses/%s/students/submissions?per_page=50' % (course_id)

[MattHanes]

After the BASE_URL should be a plus sign and not a % sign. That statement is not correct.

[MattHanes]

I think I found the github that you were referencing. I cleaned up the Python version of pull grades and it worked for me with a course that had 56 students. Here is a link: [Python] Pull Grades - Pastebin.com 

[ColinMurtaugh]

Here's the code in Canvas that's returning the error message that you're getting:

canvas-lms/submissions_api_controller.rb at e07336c91a70c6c22a34790d2ca98025e0440eab · instructure/c... 

It'll give that error if the number of student IDs that you pass in is greater than the limit on the maximum number of results per page.  This API call works a bit differently than most of the other calls that return lists of results (which would normally just be paginated), but you can work around the problem by breaking up the list of student IDs into a few chunks. 

For example, if the first call to get the students in the course returns 130 records, you could break it up into batches of, say, no more than 50 for the second call. 

Here's some code based on Matt Hanes' code (thanks, Matt!) that chunks the student_id list into sets of 50 before fetching the submissions:

get_submissions.py · GitHub 

Note that I picked a chunk size of 50 arbitrarily; that works fine today, but Instructure does reserve the right to change their max_page_size in the future.  Not likely, but something to be aware of. If that were to happen you'd need to revise the chunk size accordingly.

Good luck!

--Colin

[markpanning]

Thank you both, I will take a look.

Thank you,

Mark

[garth]

 @markpanning ‌ if you have the course_id, you can get a list of enrollments which includes the course grade:

• Enrollments - List enrollments

The API call will return a list of "enrollments":

• Enrollments - Enrollment object

Of particular interest to what you are doing are the following variables:

• "computed_current_score"
• "computed_final_score"
• "computed_current_grade"
• "computed_final_grade"

Make sure you understand the difference between the "current" and "final" score/grade.  Basically if there are any ungraded assignments in the gradebook, the "current" value will be different from the "final" value.  We run a gradebook sanity check at the mid-term and end of each semester to alert faculty to this potential significant error before they report their grades.

It is also important to note that if a grading scheme has not been applied,  the "grade" variables will be blank, i.e. there will be no letter grade assigned.

I hope this is helpful.

[markpanning]

Thank you Garth, that makes sense .  I am new to this and was not aware of the difference.  Thank you. 

I am working through the code sample from Colin and Matt, but trying to figure out the error when going after the students grade.  It processes the student ids now using the chunk of ids method, but gives me a 200 error in this part below with requests.get and at the json.loads.

Thank you,

Mark

all_grades = []

for chunk_ids in chunked_student_ids:

submission_params['student_ids[]'] = chunk_ids

# Build a request, adding the REQUEST_HEADERS to it for authentication

req = requests.get(submissions_endpoint, params=submission_params, headers=REQUEST_HEADERS)

# Load the response as JSON

grades = json.loads(req.text)

# add these grades to the full list

all_grades.extend(grades)

[mhp91381 · Accepted solution]

Wanted to report back that I got this, my first canvas script working to pull the computed_final_grade of each student in the rather large course.  Thank you all for your help.

Thank you,

Mark

[garth]

awesome!