How do you call the API from an exteral server?

[tjones1]

I have an LTI tool working on a secure server.

I'm trying to GET a specific Assignment with Jquery ajax so I can PUT it back with an update to the external_tool_tag_attributes: { url:

$.ajax({

            type: "GET",            // Type of request to be send

            url: canvasapi,          // Url+token to which the request is sent

            contentType: "application/json; charset=utf-8",

            dataType: "jsonp",     // type of data

            success: function(data, status, jqXHR)

            {

                console.log( "success status: "+status );

                console.log( "success data: "+data );

                console.log( "success xhr text: "+jqXHR.responseText );

            },

            jsonp: false,            // should use Callback below

            jsonpCallback: function(data)

            {

                //var asgndata = JSON.parse(data);// or //json_decode(data);

                //console.log( "jsonp asgndata: "+asgndata );

                console.log( "jsonp data: "+data );// undefined  parser error in their return data

            },

            error: function (jqXHR, status)

            {

                console.log( "ERR status: "+status ); // parser error

                console.log( "ERR xhr text: "+jqXHR.responseText );// undefined

            }

        });

But it returns with errors:

I can paste the url+token in the browser and it returns what I need.

I've tried other API calls with no success.

What is the best way to call the API from an external server?

[kenneth_larsen]

 @tjones1 ​, what language are you using for your LTI tool? I try to avoid passing tokens using ajax due to the fact that someone can inspect your code and gain access to the token you are using. I would recommend using whatever programming language you are working in to handle your API calls on a separate page and then use the ajax request to pull from that page.

[tjones1]

The tool is using PHP, the ajax above was for a quick test.

No one is using the tool yet.

So, does anyone have php examples for retrieving an assignment from the api?

[kenneth_larsen]

I develop all of my LTI tools using PHP (that's what my department had for me to work with). Here is one of the files I use to work with API calls using PHP. I created functions for the basic types of API calls (GET, PUT, POST & DELETE) and then I create a function for specific API calls that pass the necessary parameters to the curl functions. The file only has the calls that I used for a specific project but you should be able to figure out how to add additional functions by looking through those that are in there. I adapted it a little and added two variables at the top ($canvasDomain and $token).

1. Update $canvasDomain (line 4) with the Canvas instance for the API you want to access (example: usu.instructure.com)
2. Paste your generated OAuth token into the $token variable on line 5.

Include the API file on your PHP page and then pass in the information that you want. For example, if you want to create a list of links to all of the assignments in your course you would do something like this:

require_once 'resources/canvasAPI.php';
$courseID = '12345';
$assignments = listAssignments($courseID);
echo '<ul>';
foreach ($assignments as $assignment) {
  echo '<li><a href="https://domain.instructure.com/courses/' . $courseID . '/assignments/' . $assignment->id . '" target="_blank"> ' . $assignment->name . '</a></li>';
}
echo '</ul>';

Hopefully that will save you some time in your creation process. If you need additional help with the LTI or OAuth portions of the creating a tool in PHP, let me know.

[tjones1]

This was very helpful.

I'm doing something similar with curl and made it past the Syntax Error in the screen shot.

Thanks for your help.

[marinated_pork]

Have you tried this request without calling JSON.parse? In Javascript you don't need to parse a JSON response unless it is a JSON string.  Just treat the response like any other Javascript object and continue with your logic.

[tjones1 · Accepted solution]

For all noobies like me... Learn to cURL

No more errors.

[kopplik]

I have not found where you can use ajax unless you are on the same domain as the server you are calling; without having to major changes. I found the information looking up cross-origin resources sharing (CORS). If anyone else finds a way around this please post it.