Submit file to assignment via API

[juan_londono]

Hi

I'm trying to submit an assignment via the API using C#. I have the file uploaded to the user's folder and now I need to link the file (with id =28386) to the assignment (id=1855) but I get a status  code 400 : "Bad Request" because of "No valid file ids given". I think it's the same issue as in https://community.canvaslms.com/thread/12970-submit-assignment-via-api 

This is my code:

Dictionary<string, string> vars = new Dictionary<string, string>();

vars.Add("comment[text_comment]", "My comments here");
vars.Add("submission[submission_type]", "online_upload");
vars.Add("submission[file_ids][]", "28386"); // also tried without the '[]'

var p1Content = new FormUrlEncodedContent(vars.ToArray());
using (HttpResponseMessage response = await httpPOST(baseUrl, "/api/v1/courses/330/assignments/1855/submissions", accessToken, p1Content))
{

}

Many thanks in advanced for your help

[pklove]

You need to upload the file as a submission, not to the user's folder.

So the first step is to use the submission upload file endpoint   Submissions - Canvas LMS REST API Documentation :

    POST /api/v1/courses/:course_id/assignments/:assignment_id/submissions/:user_id/files

I'm guessing you have been using the /api/v1/folders/... endpoint as the first step.

[elf]

I cannot seem to upload the file to the right place.

I'm using:

curl -sH "Authorization: Bearer $token" https://ltu.instructure.com/api/v1/courses/57/assignments/65857/submissions/$target/files -F 'name=test.pdf' -F 'size=706353' -F 'parent_folder_path='

I've tried with
$target=self
$target=$myuserid
but these both result in the error "The specified resource does not exist." (I guess it's because I'm a teacher?)

If I try with

$target=$theiruserid

I get the error "user not authorised to perform that action". I have grading rights, but not any admin rights (I'm a teacher/examiner for the course).

I have also tried with and without "parent_folder_path" and I have tried adding "-X POST" but to no avail.

If I use "https://ltu.instructure.com/api/v1/courses/57/files" instead, I can upload the file, but then I cannot submit it to the assignment:

curl -siH "Authorization: Bearer $token" https://ltu.instructure.com/api/v1/courses/57/assignments/65857/submissions -X POST -F "submission[file_ids][]=$canvasfileid" -F "submission[user_id]=$theiruserid" -F "submission[submission_type]=online_upload"

gives the error 400 Bad Request "No valid file ids given".

What am I doing wrong? How can I submit a file as a user like it says here: Submissions - Canvas LMS REST API Documentation 

Thanks!

Erik

[jsavage2]

Hi Erik,

Unfortunately, teachers cannot submit assignments on behalf of students this way. To use the API on behalf of another user, one must be an administrator with the “masquerade” permission.

Letting teachers submit assignments was supposed to be on the feature list for Q4 2019, but I don’t know what happened to that. I’ve been meaning to post a question about that myself…

[elf]

Thanks!

I cannot find anything about this on Upcoming Canvas Changes.

Apparently it is under consideration, see "Submit an assignment on behalf of a student" under:

Ideas 

Erik

[stuart_ryan]

Hi  @juan_londono ,
How did you go with this, was Peter's reply helpful and able to get you up and running with the Submit Assignments API?

Please let us know how you get on.

Cheers,
Stuart

[stuart_ryan]

Hi  @juan_londono ,

As we haven't heard back from you, I am going to mark this question as assumed answered for the time being. If you have any follow up questions, please do not hesitate to get back to us and we can try to help you out further.

Cheers,

Stuart