Community hub - technical specification

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

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 to call 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)

Note: this table contains all tokens used to call a remote entity. It also contains all tokens that remote entities use to call (these tokens must be the same that the ones into the external_tokens table)

registration process

1. the hub admin goes on hub settings page => settings has save with set_config
2. the hub admin presses register and is redirected to the hub directory registration page. During this redirection the token used by the hub directory to call the hub is sent.
3. the hub admin enters a recaptcha on the hub directory registration page. It is mandatory to avoid people to write script automatically registering.
4. the hub directory calls by web service the hub to retrieve the information.
5. the hub directory calls by web service the hub to confirm the registration. The hub directory gives a token to the hub in order to call him. The hub and the hub directory saves both of these tokens into their respective communication tables. they can now talk to each others.

update process

1. the hub admin changes the settings.
2. the hub admin presses update registration.
3. the hub calls by web service the update info function on the hub directory. The update info function calls by web services the confirm the registration function on the hub.

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 hidden from the admin user interface. Hub admin are restricted 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

exactly the same as for "Hub registration on hub directory".

security design

exactly the same as for "Hub registration on hub directory".

Course publication

tables

on the hub server we have a class 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 class named hub_global_course_directory containg all public published courses into all public hubs (Fields descriptions):

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 class named hub_published_course containg all published courses (Fields descriptions):

Name	Type	Description
id	int	Standard autoincrement
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

communication

exactly the same as updating a registration for "Hub registration on hub directory". Files are sent calling a upload.php file.

security design

same as others

Operations

Following the different communication operations expected between Moodle.org, hub servers and Moodle site.

Moodle site and Hub server

Moodle.org Hub directory and (Moodle.org) Hub server

Moodle site and Moodle.org Hub directory

Method

We are going to use web service. However we create a new /hub/webservice.php entry point, that will by pass $CFG->enablewebservice and consider a protocol as activated.

Site/Hub Registration operations

1. The site/hub creates a specific ws user, a specific ws role, a specific ws service and a specific token.
2. The site/hub sends by POST the web service token to the hub server/hub directory.
3. The hub server/hub directory creates a specific ws user, a specific ws role, a specific ws service and a specific token.
4. The hub server/hub directory calls the web service function: confirm_registration($thisisyourtokentocallme).
5. Finally the hub server/hub directory calls the web service call get_info function for its first time

Unknown caller operations

the hub/webservice.php entry point should by pass token authentication for this specific listed function

Operation list

• global search
• search courses on a hub
• site user rating (TBD)
• site user comment (TBD)
• get hub list from the hub directory

Other operations

The site/hub server/directory should all have specific token to talk to each other.

Security

Disable generated service and token

the security problems: somebody uses the hub access to execute other functions (either bug in moodle or admin misconfiguration); somebody uses normal services to execute hub function (site misconfiguration)
Solution: generated service and token should not be usable through normal /webservice/ entry points. Administration should not list the generated service and token. Cannot create a service with hub function.

Hacking testing

1. hack client sites and updated the hub info with spam
2. hack the hub and then tried to attack all client sites - probably some exploit of older version, or at least get as much emails and personal data from all sites

Note

• we need an option on settings page that:

1. delete previous user,role,service,and token.
2. Then the site rebuilds them.
3. The site would just call a ws function confirm_registration($thisisyourtokentocallme) on the hub server/hub directory.

• we need to decide which ws protocol the community hub will use

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

Registered Site

Will have one new user for every hub it registers with.

"Hub User" - Role for Hub (private token)

• moodle/hub:registerinfo for getting site information
• moodle/hub:registercourses for getting course listing
• moodle/hub:confirmsiteregistration 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

Registered Site

the following service will exist on any Moodle site (but disabled till a first token is linked to it)

"Hub server"

• getting site information function
• getting course listing function
• confirm the site 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'.

Registered Site

"Hub servers": they all have their own $huburl.'_hub_user' user

• Their role is 'Hub User'
• Their service is 'Hub server'

See also

• Community hub