A REStful webservice plugin for Moodle LMS
A REStful webservice plugin for Moodle LMS
This plugin allows Moodle’s webservice interface to operate in a more RESTFul way.
Instead of each webservice call having a URL query parameter define what webservice function to use, webservice functions are made available by discrete URLS.
This makes it easier to integrate Moodle with modern interfaces that expect a RESTful interface from other systems.
This plugin also supports sending requests to Moodle webservices using the JSON format.
Finally, by default all Moodle webservice requests return the HTTP status code of 200 regardless of the success or failure of the call. This plugin will return 4XX series status codes if calls are malformed, missing data or unauthorised. This allows external services communicating with Moodle to determine the success or failure of a webservice call without the need to parse the body of the response.
There were two related reasons for making this plugin. The first was to solve a technical problem; interfacing Moodle to a service that required each Moodle webservice to be callable from a unique URL. The second was to advance the maturity of Moodle’s webservice interface.
The “Richardson Maturity Model” (https://martinfowler.com/articles/richardsonMaturityModel.html) describes the maturity of a web applications API/ webservice interface in a series of levels.
Moodle is currently Level 0 or in the “swamp of POX”. As described be Fowler, Moodle “is using HTTP as a tunneling mechanism for your own remote interaction mechanism”
This plugin aims to extend the maturity of Moodle’s webservice interface to “Level 1: Resources” by making each webservice function available as a discrete URL.
Moodle version | Branch |
---|---|
Moodle 4.2 - 4.4 | MOODLE_402_STABLE |
Moodle 3.9 - 4.1 | master |
The following sections outline how to install the Moodle plugin.
To install the plugin in Moodle via the command line: (assumes a Linux based system)
<moodledir>/webservice/restful
sudo -u www-data php admin/cli/upgrade
Note: the user may be different to www-data on your system.To install the plugin in Moodle via the Moodle User Interface:
Once the plugin has been installed in Moodle, the following minimal setup is required:
Follow these instructions if you do not currently have any webservies enabled and/or unfamiliar with Moodle webservices.
There are several steps required to setup and enable webservices in Moodle, these are covered in the Moodle documentation that can be found at: https://docs.moodle.org/34/en/Using_web_services
It is recommended you read through these instructions first before attempting Moodle webservice Setup.
Data can be sent to Moodle webservices using the following encodings:
Use the ‘Content-Type’ HTTP header to notify Moodle which format is being used per request.
Data can be received from Moodle webservices using the following encodings:
Use the ‘Accept’ HTTP header to notify Moodle which format to return per request.
When using the RESTful plugin there are several differences to other Moodle webservice plugins, these are summarised below:
Below are several examples of how to structure requests using the cURL command line tool.
The following example uses the core_course_get_courses webservice function to get the course with id 6. The request sent to Moodle and the response received back are both in JSON format.
To use the below example against an actual Moodle instance:
curl -X POST \
-H "Content-Type: application/json" \
-H "Accept: application/json" \
-H 'Authorization: {token}' \
-d'{"options": {"ids":[6]}}' \
"https://localhost/webservice/restful/server.php/core_course_get_courses"
The following example uses the core_course_get_courses webservice function to get the course with id 6. The request sent to Moodle and the response received back are both in XML format.
To use the below example against an actual Moodle instance:
curl -X POST \
-H "Content-Type: application/xml" \
-H "Accept: application/xml" \
-H 'Authorization: {token}' \
-d'
6
' \
"https://localhost/webservice/restful/server.php/core_course_get_courses"
The following example uses the core_course_get_courses webservice function to get the course with id 6. The request sent to Moodle is in REST format and the response received back is in JSON format.
NOTE: This plugin can only accept requests in REST format. Responses must be in JSON or XML format.
To use the below example against an actual Moodle instance:
curl -X POST \
-H "Content-Type: application/x-www-form-urlencoded" \
-H "Accept: application/json" \
-H 'Authorization: {token}' \
-d'options[ids][0]=6' \
"https://localhost/webservice/restful/server.php/core_course_get_courses"
This Moodle webservice plug-in allows for requests and responses to be different formats.
The following example uses the core_course_get_courses webservice function to get the course with id 6. The request sent to Moodle is in JSON format and the response received back is in XML format.
To use the below example against an actual Moodle instance:
curl -X POST \
-H "Content-Type: application/json" \
-H "Accept: application/xml" \
-H 'Authorization: {token}' \
-d'{"options": {"ids":[6]}}' \
"https://localhost/webservice/restful/server.php/core_course_get_courses"
The received response will look like:
6
search test
1
10003
...
The following cURL example will generate various types of errors. These are useful when testing.
This request is missing the authorization header.
curl -i -X POST \
-H "Content-Type: application/json" \
-H "Accept: application/json" \
-d'{"options": {"ids":[6]}}' \
"http://moodle.local/webservice/restful/server.php/core_course_get_courses"
This request contains an invalid webservice token.
curl -i -X POST \
-H "Content-Type: application/json" \
-H "Accept: application/json" \
-H 'Authorization: xxx' \
-d'{"options": {"ids":[6]}}' \
"http://moodle.local/webservice/restful/server.php/core_course_get_courses"
This request is missing the Accept header.
curl -i -X POST \
-H -i "Content-Type: application/json" \
-H 'Authorization: e71561c88ca7f0f0c94fee66ca07247b' \
-d'{"options": {"ids":[6]}}' \
"http://moodle.local/webservice/restful/server.php/core_course_get_courses"
The next big step will be to update the interface to “Level 2” that is support HTTP verbs, like get and post.
Which verb to use will likely be dependant on the ws function name that is being invoked.
If you have any suggestions for functionality, they can be requests by raising a GitHub issue: https://github.com/catalyst/moodle-webservice_restful/issues
This plugin was developed by Catalyst IT Australia:
Issues, and pull requests using github are welcome and encouraged!
https://github.com/catalyst/moodle-webservice_restful/issues
If you would like commercial support or would like to sponsor additional improvements
to this plugin please contact us: