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'''THIS IS A DRAFT'''
'''THIS IS A DRAFT'''


== Option 1: Convert ==
== Preamble ==


=== The following tables need fields and data converted ===
This change is required to be able to show times to users that are appropriate to their timezones, rather than the timezone the server is in. Currently this is not possible as mahara is storing the time data in a timezone '''un'''aware format.


<pre>
=== Use cases ===
activity_queue
 
artefact
This will be relevant for at least two use cases:
artefact_cron
 
artefact_internal_profile_email
==== Users in timezones different to the server ====
artefact_log
 
artefact_plans_task
There are numerous cases where times are shown to users in regards to when posts were made, messages were sent, etc. These can be way off for someone in a timezone different to the server.
artefact_resume_certification
 
artefact_resume_educationhistory
==== If the server moves ====
artefact_resume_employmenthistory
 
artefact_resume_membership
At some point, a mahara server may well move. Admins may wish to change the times of the server itself, or within mahara. If the time data is stored without timezone awareness, then this would upset the data.
artefact_resume_personal_information
 
auth_cron
== Implementation ==
blocktype_externalfeed_data
 
blocktype_wall_post
=== Settings ===
collection
 
cron
==== Users ====
export_cron
 
favorite
An option will be made available to users in the general account section of their settings page, ideally immediately above or below the language setting.
"group"
 
group_member
There will be no user timezone setting by default.
group_member_invite
 
group_member_request
==== Institutions ====
import_cron
 
import_queue
An option will be made available on the institution creation page and in the institution settings page.
institution
 
interaction_cron
There will be no institution timezone setting by default.
interaction_forum_edit
 
interaction_forum_post
===== Which institution's settings of several will the user respect? =====
interaction_instance
 
notification_cron
The first institution that a user is added to where the institution has a timezone set will become the user's default timezone, and the user will be notified with instructions to change it if this was not desired.
notification_emaildigest_queue
Subsequent institution additions where the institution has a timezone set will notify the user that it is a differing timezone, and offer instructions to the user on how to adopt that timezone.
notification_internal_activity
 
search_cron
==== Server admins ====
site_content
 
site_data
Server admins will be able to set the server default timezone in the Site options page in the site settings fieldset.
usr
 
usr_friend
The default value for that timezone will be "Server timezone" which is what is reported by PHP at install or upgrade time.
usr_friend_request
 
usr_infectedupload
=== Setting priority ===
usr_institution
 
usr_institution_request
The priority of the timezone settings is:
usr_password_request
 
usr_registration
* User timezone setting has highest priority.
usr_session
* If user timezone setting is not set, the site-wide timezone setting will be used.
usr_watchlist_view
 
view
=== Schema/Code ===
view_access
 
view_visit
MySQL timestamps have been stored as 'datetime'.
</pre>
PostgreSQL timestamps have been stored as 'timestamp no time zone'.
 
Neither of these datatypes retain timezone perspective. They ought to have been recorded as 'timestamp' and 'timestamp with time zone' respectively.
 
From the [http://docs.moodle.org/dev/XMLDB_column_types Moodle XMLDB docs]:
<pre>(*) Note that, although datetime types are supported by XMLDB, all datetime/timestamp columns under Moodle are declared as integer(10) and filled with Unix timestamps, so this type of column shouldn't be used at all (in fact, the XMLDB Editor doesn't show them as an available option).</pre>
 
The datetime/timestamp fields in the database ought to be converted to integer(10) so as to take the unix timestamp.
 
==== Applying the timezone ====
 
The timezone name (e.g. "Pacific/Auckland") for the user will be loaded into the user object at the point the user logs in or changes the setting.


=== Conversion process ===
The current offset for that timezone will be applied to the time data pulled from the database before the timestamp is converted to human-readable format.


==== Schema ====
== Technical Details ==


The datetime fields in the database ought to be converted to integer so as to take the unix timestamp.
==== The following fields need converting ====


==== Stored data ====
<pre>
activity_queue
ctime
artefact
ctime
mtime
atime
artefact_cron
nextrun
artefact_internal_profile_email
expiry
artefact_log
"time"
artefact_plans_task
completiondate
artefact_resume_personal_information
dateofbirth
auth_cron
nextrun
blocktype_cron
nextrun
blocktype_externalfeed_data
lastupdate
blocktype_wall_post
postdate
collection
ctime
mtime
cron
nextrun
export_cron
nextrun
favorite
ctime
mtime
"group"
ctime
mtime
group_member
ctime
group_member_invite
ctime
group_member_request
ctime
grouptype_cron
nextrun
import_cron
nextrun
import_queue
expirytime
institution
expiry
interaction_cron
nextrun
interaction_forum_edit
ctime
interaction_forum_post
ctime
interaction_instance
ctime
notification_cron
nextrun
notification_emaildigest_queue
ctime
notification_internal_activity
ctime
search_cron
nextrun
site_content
ctime
mtime
site_data
ctime
usr
expiry
lastlogin
lastlastlogin
lastaccess
suspendedctime
ctime
usr_friend
ctime
usr_friend_request
ctime
usr_infectedupload
"time"
usr_institution
ctime
expiry
usr_institution_request
ctime
usr_password_request
expiry
usr_registration
expiry
usr_session
ctime
usr_watchlist_view
ctime
view
startdate
stopdate
ctime
mtime
atime
submittedtime
view_access
startdate
stopdate
ctime
</pre>


The data contained in these fields then needs to be converted from the machine time to unix time
==== Schema ====


==== Code changes ====
The install.xml file will need to be editted in respect to the above list of fields.


Check all the places in the code where the date is displayed in human readable format.
=== Updating ===


==== Resources ====
This is a way to do so (example ctime field of activity_queue table):


http://stackoverflow.com/questions/2689428/mysql-convert-db-from-local-time-to-utc
<pre>
http://stackoverflow.com/questions/2700197/sql-server-convert-date-field-to-utc
      $tabledata = get_records_array('activity_queue', '', '', '', 'id,ctime');
     
      $table = new XMLDBTable('activity_queue');
      $field = new XMLDBField('ctime');
      drop_field($table, $field);


      $field->setAttributes(XMLDB_TYPE_INTEGER, 10, XMLDB_UNSIGNED, null);
      add_field($table, $field);
     
      if ( is_array($tabledata) ) {
        foreach ($tabledata as $tdata) {
            $new = new stdClass;
            $new->ctime = strtotime($tdata->ctime);
 
            $where = new stdClass;
            $where->id = $tdata->id;
 
            update_record('activity_queue', $new, $where );
        }
      }
</pre>


== Option 2: User offset ==
but it will not work on large sites, so we '''cannot use this approach'''.


Uglier but less traumatic.
Instead, we need to find a way to do the conversion in SQL (both on Postgres and MySQL) as much as possible. If we don't, many people will not be able to upgrade.


=== Schema ===
==== Code changes ====


New table: timezones eg:
Check all the places in the code where the date is displayed in human readable format.


<pre>timezone (varchar) | offset (int)
The following template files have human-readable time records.
-------------------+-------------
<pre>
Pacific/Auckland  | 0
./htdocs/interaction/forum/theme/raw/editpost.tpl
UTC                | 43200
./htdocs/artefact/blog/theme/raw/atom.xml.tpl
./htdocs/artefact/blog/theme/raw/posts.tpl
./htdocs/artefact/file/blocktype/filedownload/theme/raw/filedownload.tpl
./htdocs/artefact/file/export/html/theme/raw/index.tpl
./htdocs/artefact/file/theme/raw/form/filelist.tpl
./htdocs/blocktype/groupviews/theme/raw/groupviews.tpl
./htdocs/blocktype/newviews/theme/raw/newviews.tpl
./htdocs/export/html/theme/raw/footer.tpl
./htdocs/export/leap/theme/raw/header.tpl
./htdocs/interaction/forum/theme/raw/atom.xml.tpl
./htdocs/interaction/forum/theme/raw/edittopic.tpl
./htdocs/interaction/forum/theme/raw/simplepost.tpl
./htdocs/interaction/forum/theme/raw/topics.tpl
./htdocs/theme/raw/templates/form/viewacl.tpl
./htdocs/theme/raw/templates/group/info.tpl
./htdocs/theme/raw/templates/group/membersearchresults.tpl
./htdocs/theme/raw/templates/group/topicrows.tpl
./htdocs/theme/raw/templates/performancefooter.tpl
./htdocs/theme/raw/templates/portfoliosearchresults.tpl
./htdocs/theme/raw/templates/user/sendmessage.tpl
./htdocs/theme/raw/templates/view/accesslistrow.tpl
./htdocs/theme/raw/templates/view/sharedviewrows.tpl
./htdocs/theme/raw/templates/view/view.tpl
</pre>
</pre>
In usr table, new field: timezone


=== Usage ===
There will be other places where the code needs changing as it will be coming from the database in a different format to what it currently is.
 
==== Resources ====


When displaying dates to users, use the stored data, convert to epoch, add offset, convert to human readable.
* http://stackoverflow.com/questions/2689428/mysql-convert-db-from-local-time-to-utc
* http://stackoverflow.com/questions/2700197/sql-server-convert-date-field-to-utc

Latest revision as of 17:43, 11 July 2020

Timezone support for Mahara

THIS IS A DRAFT

Preamble

This change is required to be able to show times to users that are appropriate to their timezones, rather than the timezone the server is in. Currently this is not possible as mahara is storing the time data in a timezone unaware format.

Use cases

This will be relevant for at least two use cases:

Users in timezones different to the server

There are numerous cases where times are shown to users in regards to when posts were made, messages were sent, etc. These can be way off for someone in a timezone different to the server.

If the server moves

At some point, a mahara server may well move. Admins may wish to change the times of the server itself, or within mahara. If the time data is stored without timezone awareness, then this would upset the data.

Implementation

Settings

Users

An option will be made available to users in the general account section of their settings page, ideally immediately above or below the language setting.

There will be no user timezone setting by default.

Institutions

An option will be made available on the institution creation page and in the institution settings page.

There will be no institution timezone setting by default.

Which institution's settings of several will the user respect?

The first institution that a user is added to where the institution has a timezone set will become the user's default timezone, and the user will be notified with instructions to change it if this was not desired. Subsequent institution additions where the institution has a timezone set will notify the user that it is a differing timezone, and offer instructions to the user on how to adopt that timezone.

Server admins

Server admins will be able to set the server default timezone in the Site options page in the site settings fieldset.

The default value for that timezone will be "Server timezone" which is what is reported by PHP at install or upgrade time.

Setting priority

The priority of the timezone settings is:

  • User timezone setting has highest priority.
  • If user timezone setting is not set, the site-wide timezone setting will be used.

Schema/Code

MySQL timestamps have been stored as 'datetime'. PostgreSQL timestamps have been stored as 'timestamp no time zone'.

Neither of these datatypes retain timezone perspective. They ought to have been recorded as 'timestamp' and 'timestamp with time zone' respectively.

From the Moodle XMLDB docs:

(*) Note that, although datetime types are supported by XMLDB, all datetime/timestamp columns under Moodle are declared as integer(10) and filled with Unix timestamps, so this type of column shouldn't be used at all (in fact, the XMLDB Editor doesn't show them as an available option).

The datetime/timestamp fields in the database ought to be converted to integer(10) so as to take the unix timestamp.

Applying the timezone

The timezone name (e.g. "Pacific/Auckland") for the user will be loaded into the user object at the point the user logs in or changes the setting.

The current offset for that timezone will be applied to the time data pulled from the database before the timestamp is converted to human-readable format.

Technical Details

The following fields need converting

activity_queue	
	ctime
artefact	
	ctime
	mtime
	atime
artefact_cron	
	nextrun
artefact_internal_profile_email	
	expiry
artefact_log	
	"time"
artefact_plans_task	
	completiondate
artefact_resume_personal_information	
	dateofbirth
auth_cron	
	nextrun
blocktype_cron	
	nextrun
blocktype_externalfeed_data	
	lastupdate
blocktype_wall_post	
	postdate
collection	
	ctime
	mtime
cron	
	nextrun
export_cron	
	nextrun
favorite	
	ctime
	mtime
"group"	
	ctime
	mtime
group_member	
	ctime
group_member_invite	
	ctime
group_member_request	
	ctime
grouptype_cron	
	nextrun
import_cron	
	nextrun
import_queue	
	expirytime
institution	
	expiry
interaction_cron	
	nextrun
interaction_forum_edit	
	ctime
interaction_forum_post	
	ctime
interaction_instance	
	ctime
notification_cron	
	nextrun
notification_emaildigest_queue	
	ctime
notification_internal_activity	
	ctime
search_cron	
	nextrun
site_content	
	ctime
	mtime
site_data	
	ctime
usr	
	expiry
	lastlogin
	lastlastlogin
	lastaccess
	suspendedctime
	ctime
usr_friend	
	ctime
usr_friend_request	
	ctime
usr_infectedupload	
	"time"
usr_institution	
	ctime
	expiry
usr_institution_request	
	ctime
usr_password_request	
	expiry
usr_registration	
	expiry
usr_session	
	ctime
usr_watchlist_view	
	ctime
view	
	startdate
	stopdate
	ctime
	mtime
	atime
	submittedtime
view_access	
	startdate
	stopdate
	ctime

Schema

The install.xml file will need to be editted in respect to the above list of fields.

Updating

This is a way to do so (example ctime field of activity_queue table):

      $tabledata = get_records_array('activity_queue', '', '', '', 'id,ctime');
      
      $table = new XMLDBTable('activity_queue');
      $field = new XMLDBField('ctime');
      drop_field($table, $field);

      $field->setAttributes(XMLDB_TYPE_INTEGER, 10, XMLDB_UNSIGNED, null);
      add_field($table, $field);
      
      if ( is_array($tabledata) ) {
        foreach ($tabledata as $tdata) {
            $new = new stdClass;
            $new->ctime = strtotime($tdata->ctime);
  
            $where = new stdClass;
            $where->id = $tdata->id;
  
            update_record('activity_queue', $new, $where );
        }
      }

but it will not work on large sites, so we cannot use this approach.

Instead, we need to find a way to do the conversion in SQL (both on Postgres and MySQL) as much as possible. If we don't, many people will not be able to upgrade.

Code changes

Check all the places in the code where the date is displayed in human readable format.

The following template files have human-readable time records.

./htdocs/interaction/forum/theme/raw/editpost.tpl
./htdocs/artefact/blog/theme/raw/atom.xml.tpl
./htdocs/artefact/blog/theme/raw/posts.tpl
./htdocs/artefact/file/blocktype/filedownload/theme/raw/filedownload.tpl
./htdocs/artefact/file/export/html/theme/raw/index.tpl
./htdocs/artefact/file/theme/raw/form/filelist.tpl
./htdocs/blocktype/groupviews/theme/raw/groupviews.tpl
./htdocs/blocktype/newviews/theme/raw/newviews.tpl
./htdocs/export/html/theme/raw/footer.tpl
./htdocs/export/leap/theme/raw/header.tpl
./htdocs/interaction/forum/theme/raw/atom.xml.tpl
./htdocs/interaction/forum/theme/raw/edittopic.tpl
./htdocs/interaction/forum/theme/raw/simplepost.tpl
./htdocs/interaction/forum/theme/raw/topics.tpl
./htdocs/theme/raw/templates/form/viewacl.tpl
./htdocs/theme/raw/templates/group/info.tpl
./htdocs/theme/raw/templates/group/membersearchresults.tpl
./htdocs/theme/raw/templates/group/topicrows.tpl
./htdocs/theme/raw/templates/performancefooter.tpl
./htdocs/theme/raw/templates/portfoliosearchresults.tpl
./htdocs/theme/raw/templates/user/sendmessage.tpl
./htdocs/theme/raw/templates/view/accesslistrow.tpl
./htdocs/theme/raw/templates/view/sharedviewrows.tpl
./htdocs/theme/raw/templates/view/view.tpl

There will be other places where the code needs changing as it will be coming from the database in a different format to what it currently is.

Resources