Community hub - technical specification
Implementation
Site
In Moodle core we add:
- new registration form
- community block (search course, import and restore course)
- course publication operation
Hub
A plugin /local/hub/
Hub directory
A plugin /local/hubdirectory
Hub registration on hub directory
tables
on the hub directory we have a class named hub_directory containg all registered hubs :
| Name | Type | Description |
|---|---|---|
| id | int | Standard autoincrement |
| name | varchar | Name of the hub |
| description | text | Description of the hub |
| url | varchar | The full URL to the hub front page |
| token | varchar | The token used to call the hub |
| trusted | int | Is the hub trusted? |
| language | varchar | What is the primary language of this hub? (blank for multilanguage) |
| timeregistered | int | Time that the hub was first registered |
| timemodified | int | Time that the hub was last modified |
| contactname | varchar | Name of the contact person |
| contactemail | varchar | Email of the contact person |
| imageurl | varchar | hub logo url |
| visible | int | is hub visible (i.e. enable field) |
| prioritise | int | is this hub prioritised |
| courses | int | Number of courses on this hub |
| sites | int | Number of sites on this site |
| privacy | varchar | "public"/"private" |
communication
Communications between hub and hub directory are two ways, they can call each other by web service. For any hub/hub directory communication, we record the remote entity (i.e. hub directory/hub) in a table named hub_communication or hub_directory_communication. This is mainly used to remember the token used by the remote entity and the name of the remote entity. It's also used as a flag to know if a registration attempt has been confirmed.
| Name | Type | Description |
|---|---|---|
| id | int | Standard autoincrement |
| localtype | varchar | Is our Moodle site a: Site, Hub or Hub directory |
| token | text | the token used for this communication |
| localws | varchar | What kind of entity is our site in this communication. Are we server or client? |
| remotetype | varchar | Is the remote Moodle site a: Site, Hub or Hub directory |
| remotename | varchar | Full name of the remote site |
| remoteurl | varchar | URL of the remote entity |
| confirmed | int | Is this confirmation confirmed (in case the registration/update failed) |
registration process
- the hub admin goes on hub settings page => settings are saved with set_config
- the hub admin presses register and is redirected to the hub directory registration page. This redirection has the token used by the hub directory.
- the hub admin enters a recaptcha on the hub directory registration page. It is mandatory to avoid people to write script automatically registering.
- the hub directory redirect the hub admin to his own site on a confirmation page. The redirection has the token used by the hub.
update process
- the hub admin changes the settings.
- the hub admin presses update registration.
- the hub calls by web service the update info function on the hub directory.
security design
- because there is a recaptcha, only human being can register.
- all other communications are protected by Moodle ws security design
- In order to use web service we automatically create Users/Services/Roles/Functions. All created users, web services functions, web services and web service tokens are visible in the admin user interface. Hub admin should not to delete them, neither create some with the same names. Hub admin can only modify the roles in order to restrict the capabilities to use some of the functions. To know about automatically created Users/Services/Roles, see their respective sections in this same page.
Site registration on a hub server
tables
on the hub server we have a class named hub_site_directory containg all registered sites :
| Name | Type | Description |
|---|---|---|
| id | int | Standard autoincrement |
| name | varchar | Name of the site |
| description | text | Description of the site |
| url | varchar | The full URL to the site front page |
| token | varchar | The token used to call the site |
| trusted | int | Is the site trusted? |
| language | varchar | What is the primary language of this site? (blank for multilanguage) |
| timeregistered | int | Time that the site was first registered |
| timemodified | int | Time that the site was last modified |
| contactname | varchar | Name of the contact person |
| contactemail | varchar | Email of the contact person |
| contactphone | varchar | Phone of the contact person |
| contactable | int | can we contact the person |
| imageurl | varchar | site logo url |
| visible | int | is site visible (i.e. enable field) |
| prioritise | int | is this site prioritised |
| countrycode | varchar | country code ISO 3166 |
| regioncode | varchar | region code ISO 3166-2 |
| street | varchar | street |
| geolocation | varchar | lattitude and longitute (like in googlemap/twitter) |
| moodleversion | varchar | Moodle version |
| moodlerelease | varchar | Moodle releasel |
| ip | varchar | last IP of this site |
| courses | int | Number of courses on this site |
| users | int | Number of users on this site |
| enrolments | int | Number of enrolments on this site |
| resources | int | Number of resources on this site |
| questions | int | Number of questions on this site |
| modulenumberaverage | int | Module number average on this site |
| participantnumberaverage | int | NParticipant number average on this site |
| emailalert | int | Do we send email notification |
| privacy | varchar | "public"/"private" |
| posts | int | Number of posts on this site |
communication
The registration process is similar to "Hub registration on hub directory", except that the site doesn't create any ws token for the hub. However it creates a secret key in order to confirm the registration process. The communication between site and hub are one way, site to hub.
Course publication
tables
on the hub server we have a table named hub_course_directory containg all published courses (Fields descriptions):
| Name | Type | Description |
|---|---|---|
| id | int | Standard autoincrement |
| siteid | int | Site ID from the table hub_site_directory |
| fullname | varchar | Fullname of the course |
| description | text | Description of the course |
| courseurl | varchar | The full URL to the course |
| contributornames | varchar | Contributor names |
| coverage | varchar | Coverage |
| language | varchar | What is the language of this hub? |
| timemodified | int | Time that the course was last published |
| creatorname | varchar | Name of the creator |
| publishername | varchar | Name of the publisher |
| format | varchar | url or Zip |
| shortname | varchar | course short name |
| licenseshortname | varchar | license shortname |
| subject | varchar | subject |
| audience | varchar | |
| educationallevel | varchar | |
| coursemapid | varchar | |
| creatornotes | varchar | |
| creatornotesformat | varchar | |
| privacy | varchar | |
| downloadurl | varchar | |
| originaldownloadurl | varchar | |
| demourl | varchar | |
| trusted | int | |
| enrollable | int | |
| screenshotsids | varchar | |
| enrolcost | int | |
| enrolcostcurrency | varchar | |
| downloadcost | int | |
| downloadcostcurrency | varchar |
on the hub directory we have a table named hub_global_course_directory containg all public published courses into all public hub:
| Name | Type | Description |
|---|---|---|
| id | int | Standard autoincrement |
| hubid | int | Hub ID from the table hub_directory |
| sitename | varchar | Site name - can be blank |
| siteurl | varchar | Site URL- can be blank |
| fullname | varchar | Fullname of the course |
| description | text | Description of the course |
| courseurl | varchar | The full URL to the course |
| contributornames | varchar | Contributor names |
| coverage | varchar | Coverage |
| language | varchar | What is the language of this hub? |
| timemodified | int | Time that the course was last published |
| creatorname | varchar | Name of the creator |
| publishername | varchar | Name of the publisher |
| format | varchar | url or Zip |
| shortname | varchar | course short name |
| licenseshortname | varchar | license shortname |
| subject | varchar | subject |
| audience | varchar | |
| educationallevel | varchar | |
| coursemapid | varchar | |
| creatornotes | varchar | |
| creatornotesformat | varchar | |
| privacy | varchar | |
| downloadurl | varchar | |
| originaldownloadurl | varchar | |
| demourl | varchar | |
| trusted | int | |
| enrollable | int | |
| screenshotsids | varchar | |
| enrolcost | int | |
| enrolcostcurrency | varchar | |
| downloadcost | int | |
| downloadcostcurrency | varchar |
On the registered sites we have a table named hub_course_published containg all published courses.
communication
Sites send files calling a upload.php script on the hub.
Operations
Following the different communication operations expected between Moodle.org, hub servers and Moodle site.
Moodle site and Hub server
One way communications, site to hub.
Moodle.org Hub directory and (Moodle.org) Hub server
Moodle site and Moodle.org Hub directory
Method
We are going to use Moodle web services. We will create a new /hub/webservice.php entry point It will bypass $CFG->enablewebservice and it will consider a choosen protocol as activated.
Registration operations
- The hub creates a specific ws user, a specific ws role, a specific ws service and a specific token.
- The hub sends by POST the web service token to the site/hub directory.
Unknown caller operations
the webservice.php entry point should by pass token authentication for some public functions.
public function list
- global search
- search courses on a hub
- get hub list from the hub directory
New Roles
Moodle.org Hub list
"Public Directory User" - Role for any sites :
- moodle/hubs:view (public token for any sites) for searching the global listing
"Directory User" - Role for hub to update the listing:
- moodle/hubs:updateinfo (private token for any registered hub) for updating hub information (it creates a new private token different from the one used to call this function)
Hub server
Will have one new user per registered site, plus one for Moodle.org hub directory and one for pubic users.
"Public Hub User" - Role for any site (public token)
- moodle/hub:view for course searches
- moodle/hub:rate for rating a course
- moodle/hub:comment for commenting a course
- moodle/hub:download for downloading a course template
"Registered Hub User" - Role for registered sites (private token -> each site gets a private user)
- moodle/hub:view for course searches
- moodle/hub:rate for rating a course
- moodle/hub:comment for commenting a course
- moodle/hub:download for downloading a course template
- moodle/hub:publish for publishing a course template
- moodle/hub:updateinfo (private token for any registered site) for updating site information (it creates a new private token different from the one used to call this function)
"Moodle.org Hub Directory" - Role for Moodle.org Hub Directory (private token)
- moodle/hub:viewinfo for getting hub information
- moodle/hub:view for getting course information
- moodle/hub:confirmhubregistration confirm the registration
New Services
We will have one hidden service per role. Following their name:
Moodle.org Hub list
the following service will exist only on Moodle.org Hub directory
"Hub directory public site":
- global search function
"Hub directory hub server":
- update info function
Hub server
the following services will exist on any Moodle site (but disabled till a first token is linked to it)
"Public site":
- course searches function
- rating a course function
- commenting a course function
- downloading a course template function
"Registered site"
- course searches function
- rating a course function
- commenting a course function
- downloading a course template function
- publishing a course template function
- update info function
"Hub directory"
- getting hub information function
- getting course information function
- confirm the hub registration function
New Users
Moodle.org Hub list
A user is be linked to one role only and one service only
"Public sites": they all use the same public_directory_user user.
- His role is 'Public Directory User'
- His service is 'Hub directory public site'
"Hub servers": they all have their own $huburl."_directory_hub_user" user.
- Their role is 'Directory user'
- Their service is 'Hub directory hub server'
Hub server
"Public sites": they all use the same 'public_hub_user' user.
- His role is 'Public Hub User'
- His service is 'Public site'
"Registered sites": they all have their own $siteurl.'_registered_site_user' user.
- Their role is 'Registered Hub User'.
- Their service is 'Registered site'.
"Hub directory": they use their own $hubdirectoryurl.'_directory_user' (in case the hub directory change his url)
- Their role is 'Moodle.org Hub Directory'.
- Their service is 'Hub directory'.
