Apache::lonnavmap - Subroutines to handle and render the navigation maps
The main handler generates the navigational listing for the course,
the other objects export this information in a usable fashion for
other modules.
The navmap renderer package provides a sophisticated rendering of the
standard navigation maps interface into HTML. The provided nav map
handler is actually just a glorified call to this.
Because of the large number of parameters this function presents,
instead of passing it arguments as is normal, pass it in an anonymous
hash with the given options. This is because there is no obvious order
you may wish to override these in and a hash is easier to read and
understand then ``undef, undef, undef, 1, undef, undef, renderButton,
undef, 0'' when you mostly want default behaviors.
The package provides a function called 'render', called as
Apache::lonnavmaps::render({}).
The renderer will build an HTML table for the navmap and return
it. The table is consists of several columns, and a row for each
resource (or possibly each part). You tell the renderer how many
columns to create and what to place in each column, optionally using
one or more of the prepared columns, and the renderer will assemble
the table.
Any additional generally useful column types should be placed in the
renderer code here, so anybody can use it anywhere else. Any code
specific to the current application (such as the addition of <input>
elements in a column) should be placed in the code of the thing using
the renderer.
At the core of the renderer is the array reference COLS (see Example
section below for how to pass this correctly). The COLS array will
consist of entries of one of two types of things: Either an integer
representing one of the pre-packaged column types, or a sub reference
that takes a resource reference, a part number, and a reference to the
argument hash passed to the renderer, and returns a string that will
be inserted into the HTML representation as it.
The pre-packaged column names are refered to by constants in the
Apache::lonnavmaps namespace. The following currently exist:
- resource:
The general info about the resource: Link, icon for the type, etc. The
first column in the standard nav map display. This column also accepts
the following parameters in the renderer hash:
- resource_nolink:
If true, the resource will not be linked. Default: false, resource
will have links.
- resource_part_count:
If true (default), the resource will show a part count if the full
part list is not displayed. If false, the resource will never show a
part count.
- resource_no_folder_link:
If true, the resource's folder will not be clickable to open or close
it. Default is false. True implies printCloseAll is false, since you
can't close or open folders when this is on anyhow.
- communication_status:
-
Whether there is discussion on the resource, email for the user, or
(lumped in here) perl errors in the execution of the problem. This is
the second column in the main nav map.
- quick_status:
-
An icon for the status of a problem, with four possible states:
Correct, incorrect, open, or none (not open yet, not a problem). The
third column of the standard navmap.
- long_status:
-
A text readout of the details of the current status of the problem,
such as ``Due in 22 hours''. The fourth column of the standard navmap.
If you add any others please be sure to document them here.
An example of a column renderer that will show the ID number of a
resource, along with the part name if any:
sub {
my ($resource, $part, $params) = @_;
if ($part) { return '<td>' . $resource->{ID} . ' ' . $part . '</td>'; }
return '<td>' . $resource->{ID} . '</td>';
}
Note these functions are responsible for the TD tags, which allow them
to override vertical and horizontal alignment, etc.
Most of these parameters are only useful if you are *not* using the
folder interface (i.e., the default first column), which is probably
the common case. If you are using this interface, then you should be
able to get away with just using 'cols' (to specify the columns
shown), 'url' (necessary for the folders to link to the current screen
correctly), and possibly 'queryString' if your app calls for it. In
that case, maintaining the state of the folders will be done
automatically.
- iterator:
A reference to a fresh ::iterator to use from the navmaps. The
rendering will reflect the options passed to the iterator, so you can
use that to just render a certain part of the course, if you like. If
one is not passed, the renderer will attempt to construct one from
ENV{'form.filter'} and ENV{'form.condition'} information, plus the
'iterator_map' parameter if any.
- iterator_map:
If you are letting the renderer do the iterator handling, you can
instruct the renderer to render only a particular map by passing it
the source of the map you want to process, like
'/res/103/jerf/navmap.course.sequence'.
- navmap:
A reference to a navmap, used only if an iterator is not passed in. If
this is necessary to make an iterator but it is not passed in, a new
one will be constructed based on ENV info. This is useful to do basic
error checking before passing it off to render.
- r:
The standard Apache response object. This must be passed to the
renderer or the course hash will be locked.
- cols:
An array reference
- showParts:
A flag. If yes (default), a line for the resource itself, and a line
for each part will be displayed. If not, only one line for each
resource will be displayed.
- condenseParts:
A flag. If yes (default), if all parts of the problem have the same
status and that status is Nothing Set, Correct, or Network Failure,
then only one line will be displayed for that resource anyhow. If no,
all parts will always be displayed. If showParts is 0, this is
ignored.
- jumpCount:
A string identifying the URL to place the anchor 'curloc' at. Default
to no anchor at all. It is the responsibility of the renderer user to
ensure that the #curloc is in the URL. By default, determined through
the use of the ENV{} 'jump' information, and should normally ``just
work'' correctly.
- here:
A Symb identifying where to place the 'here' marker. Default empty,
which means no marker.
- indentString:
A string identifying the indentation string to use. By default, this
is a 25 pixel whitespace image with no alt text.
- queryString:
A string which will be prepended to the query string used when the
folders are opened or closed.
- url:
The url the folders will link to, which should be the current
page. Required if the resource info column is shown.
- currentJumpIndex:
Describes the currently-open row number to cause the browser to jump
to, because the user just opened that folder. By default, pulled from
the Jump information in the ENV{'form.*'}.
- printKey:
If true, print the key that appears on the top of the standard
navmaps. Default is false.
- printCloseAll:
If true, print the ``Close all folders'' or ``open all folders''
links. Default is true.
- filterFunc:
A function that takes the resource object as its only parameter and
returns a true or false value. If true, the resource is displayed. If
false, it is simply skipped in the display. By default, all resources
are shown.
- suppressEmptySequences:
If you're using a filter function, and displaying sequences to orient
the user, then frequently some sequences will be empty. Setting this to
true will cause those sequences not to display, so as not to confuse the
user into thinking that if the sequence is there there should be things
under it.
- suppressNavmaps:
If true, will not display Navigate Content resources. Default to
false.
In addition to the parameters you can pass to the renderer, which will
be passed through unchange to the column renderers, the renderer will
generate the following information which your renderer may find
useful:
If you want to know how many rows were printed, the 'counter' element
of the hash passed into the render function will contain the
count. You may want to check whether any resources were printed at
all.
lonnavmaps provides functions and objects for dealing with the
compiled course hashes generated when a user enters the course, the
Apache handler for the ``Navigation Map'' button, and a flexible
prepared renderer for navigation maps that are easy to use anywhere.
Encapsulating the compiled nav map
navmap is an object that encapsulates a compiled course map and
provides a reasonable interface to it.
Most notably it provides a way to navigate the map sensibly and a
flexible iterator that makes it easy to write various renderers based
on nav maps.
You must obtain resource objects through the navmap object.
- new(navHashFile, parmHashFile, genCourseAndUserOptions,
genMailDiscussStatus, getUserData):
Binds a new navmap object to the compiled nav map hash and parm hash
given as filenames. genCourseAndUserOptions is a flag saying whether
the course options and user options hash should be generated. This is
for when you are using the parameters of the resources that require
them; see documentation in resource object
documentation. genMailDiscussStatus causes the nav map to retreive
information about the email and discussion status of
resources. Returns the navmap object if this is successful, or
undef if not. You must check for undef; errors will occur when you
try to use the other methods otherwise. getUserData, if true, will
retreive the user's performance data for various problems.
- getIterator(first, finish, filter, condition):
See iterator documentation below.
- getById(id):
Based on the ID of the resource (1.1, 3.2, etc.), get a resource
object for that resource. This method, or other methods that use it
(as in the resource object) is the only proper way to obtain a
resource object.
- getBySymb(symb):
Based on the symb of the resource, get a resource object for that
resource. This is one of the proper ways to get a resource object.
- getMapByMapPc(map_pc):
Based on the map_pc of the resource, get a resource object for
the given map. This is one of the proper ways to get a resource object.
- firstResource():
Returns a resource object reference corresponding to the first
resource in the navmap.
- finishResource():
Returns a resource object reference corresponding to the last resource
in the navmap.
- getResourceByUrl(url):
Retrieves a resource object by URL of the resource. If passed a
resource object, it will simply return it, so it is safe to use this
method in code like ``$res = $navmap->getResourceByUrl($res)'', if
you're not sure if $res is already an object, or just a URL. If the
resource appears multiple times in the course, only the first instance
will be returned. As a result, this is probably useful only for maps.
- retrieveResources(map, filterFunc, recursive, bailout):
The map is a specification of a map to retreive the resources from,
either as a url or as an object. The filterFunc is a reference to a
function that takes a resource object as its one argument and returns
true if the resource should be included, or false if it should not
be. If recursive is true, the map will be recursively examined,
otherwise it will not be. If bailout is true, the function will return
as soon as it finds a resource, if false it will finish. By default,
the map is the top-level map of the course, filterFunc is a function
that always returns 1, recursive is true, bailout is false. The
resources will be returned in a list containing the resource objects
for the corresponding resources, with no structure information in
the list; regardless of branching, recursion, etc., it will be a flat
list.
Thus, this is suitable for cases where you don't want the structure,
just a list of all resources. It is also suitable for finding out how
many resources match a given description; for this use, if all you
want to know is if any resources match the description, the bailout
parameter will allow you to avoid potentially expensive enumeration of
all matching resources.
- hasResources(map, filterFunc, recursive):
Convience method for
scalar(retrieveResources($map, $filterFunc, $recursive, 1)) > 0
which will tell whether the map has resources matching the description
in the filter function.
An iterator encapsulates the logic required to traverse a data
structure. navmap uses an iterator to traverse the course map
according to the criteria you wish to use.
To obtain an iterator, call the getIterator() function of a
navmap object. (Do not instantiate Apache::lonnavmaps::iterator
directly.) This will return a reference to the iterator:
my $resourceIterator = $navmap->getIterator();
To get the next thing from the iterator, call next:
my $nextThing = $resourceIterator->next()
getIterator behaves as follows:
- getIterator(firstResource, finishResource, filterHash, condition, forceTop, returnTopMap):
All parameters are optional. firstResource is a resource reference
corresponding to where the iterator should start. It defaults to
navmap->firstResource()
for the corresponding nav map. finishResource
corresponds to where you want the iterator to end, defaulting to
navmap->finishResource(). filterHash is a hash used as a set
containing strings representing the resource IDs, defaulting to
empty. Condition is a 1 or 0 that sets what to do with the filter
hash: If a 0, then only resources that exist IN the filterHash will be
recursed on. If it is a 1, only resources NOT in the filterHash will
be recursed on. Defaults to 0. forceTop is a boolean value. If it is
false (default), the iterator will only return the first level of map
that is not just a single, 'redirecting' map. If true, the iterator
will return all information, starting with the top-level map,
regardless of content. returnTopMap, if true (default false), will
cause the iterator to return the top-level map object (resource 0.0)
before anything else.
Thus, by default, only top-level resources will be shown. Change the
condition to a 1 without changing the hash, and all resources will be
shown. Changing the condition to 1 and including some values in the
hash will allow you to selectively suppress parts of the navmap, while
leaving it on 0 and adding things to the hash will allow you to
selectively add parts of the nav map. See the handler code for
examples.
The iterator will return either a reference to a resource object, or a
token representing something in the map, such as the beginning of a
new branch. The possible tokens are:
- BEGIN_MAP:
A new map is being recursed into. This is returned after the map
resource itself is returned.
- END_MAP:
The map is now done.
- BEGIN_BRANCH:
A branch is now starting. The next resource returned will be the first
in that branch.
- END_BRANCH:
The branch is now done.
The tokens are retreivable via methods on the iterator object, i.e.,
$iterator->END_MAP.
Maps can contain empty resources. The iterator will automatically skip
over such resources, but will still treat the structure
correctly. Thus, a complicated map with several branches, but
consisting entirely of empty resources except for one beginning or
ending resource, will cause a lot of BRANCH_STARTs and BRANCH_ENDs,
but only one resource will be returned.
The other method available on the iterator is getStack, which
returns an array populated with the current 'stack' of maps, as
references to the resource objects. Example: This is useful when
making the navigation map, as we need to check whether we are under a
page map to see if we need to link directly to the resource, or to the
page. The first elements in the array will correspond to the top of
the stack (most inclusive map).
A resource object encapsulates a resource in a resource map, allowing
easy manipulation of the resource, querying the properties of the
resource (including user properties), and represents a reference that
can be used as the canonical representation of the resource by
lonnavmap clients like renderers.
A resource only makes sense in the context of a navmap, as some of the
data is stored in the navmap object.
You will probably never need to instantiate this object directly. Use
Apache::lonnavmaps::navmap, and use the ``start'' method to obtain the
starting resource.
Resource objects respect the parameter_hiddenparts, which suppresses
various parts according to the wishes of the map author. As of this
writing, there is no way to override this parameter, and suppressed
parts will never be returned, nor will their response types or ids be
stored.
resource objects have a hash called DATA ($resourceRef->{DATA}) that
you can store whatever you want in. This allows you to easily do
two-pass algorithms without worrying about managing your own
resource->data hash.
- new($navmapRef, $idString):
The first arg is a reference to the parent navmap object. The second
is the idString of the resource itself. Very rarely, if ever, called
directly. Use the nav map->getByID()
method.
Metadata Retreival
These are methods that help you retrieve metadata about the resource:
Method names are based on the fields in the compiled course
representation.
- compTitle:
Returns a ``composite title'', that is equal to $res->title()
if the
resource has a title, and is otherwise the last part of the URL (e.g.,
``problem.problem'').
- ext:
Returns true if the resource is external.
- goesto:
Returns the ``goesto'' value from the compiled nav map. (It is likely
you want to use getNext instead.)
- kind:
Returns the kind of the resource from the compiled nav map.
- randomout:
Returns true if this resource was chosen to NOT be shown to the user
by the random map selection feature. In other words, this is usually
false.
- randompick:
Returns true for a map if the randompick feature is being used on the
map. (?)
- src:
Returns the source for the resource.
- symb:
Returns the symb for the resource.
- title:
Returns the title of the resource.
- to:
Returns the ``to'' value from the compiled nav map. (It is likely you
want to use getNext instead.)
- is_map:
Returns true if the resource is a map type.
- is_problem:
Returns true if the resource is a problem type, false
otherwise. (Looks at the extension on the src field; might need more
to work correctly.)
- is_page:
Returns true if the resource is a page.
- is_sequence:
Returns true if the resource is a sequence.
Map Methods
These methods are useful for getting information about the map
properties of the resource, if the resource is a map (is_map).
- map_finish:
Returns a reference to a resource object corresponding to the finish
resource of the map.
- map_pc:
Returns the pc value of the map, which is the first number that
appears in the resource ID of the resources in the map, and is the
number that appears around the middle of the symbs of the resources in
that map.
- map_start:
Returns a reference to a resource object corresponding to the start
resource of the map.
- map_type:
Returns a string with the type of the map in it.
In order to use the resource parameters correctly, the nav map must
have been instantiated with genCourseAndUserOptions set to true, so
the courseopt and useropt is read correctly. Then, you can call these
functions to get the relevant parameters for the resource. Each
function defaults to part ``0'', but can be directed to another part by
passing the part as the parameter.
These methods are responsible for getting the parameter correct, not
merely reflecting the contents of the GDBM hashes. As we move towards
dates relative to other dates, these methods should be updated to
reflect that. (Then, anybody using these methods will not have to update
their code.)
- acc:
Get the Client IP/Name Access Control information.
- answerdate:
Get the answer-reveal date for the problem.
- awarded:
Gets the awarded value for the problem part. Requires genUserData set to
true when the navmap object was created.
- duedate:
Get the due date for the problem.
- tries:
Get the number of tries the student has used on the problem.
- maxtries:
Get the number of max tries allowed.
- opendate:
Get the open date for the problem.
- sig:
Get the significant figures setting.
- tol:
Get the tolerance for the problem.
- tries:
Get the number of tries the user has already used on the problem.
- type:
Get the question type for the problem.
- weight:
Get the weight for the problem.
Misc. functions for the resource.
- hasDiscussion:
Returns a false value if there has been discussion since the user last
logged in, true if there has. Always returns false if the discussion
data was not extracted when the nav map was constructed.
- getFeedback:
Gets the feedback for the resource and returns the raw feedback string
for the resource, or the null string if there is no feedback or the
email data was not extracted when the nav map was constructed. Usually
used like this:
for (split(/\,/, $res->getFeedback())) {
my $link = &Apache::lonnet::escape($_);
...
and use the link as appropriate.
- parts():
Returns a list reference containing sorted strings corresponding to
each part of the problem. Single part problems have only a part '0'.
Multipart problems do not return their part '0', since they typically
do not really matter.
- countParts():
Returns the number of parts of the problem a student can answer. Thus,
for single part problems, returns 1. For multipart, it returns the
number of parts in the problem, not including psuedo-part 0.
- multipart():
Returns true if the problem is multipart, false otherwise. Use this instead
of countParts if all you want is multipart/not multipart.
- responseType($part):
Returns the response type of the part, without the word ``response'' on the
end. Example return values: 'string', 'essay', 'numeric', etc.
- responseIds($part):
Retreives the response IDs for the given part as an array reference containing
strings naming the response IDs. This may be empty.
Problem resources have status information, reflecting their various
dates and completion statuses.
There are two aspects to the status: the date-related information and
the completion information.
Idiomatic usage of these two methods would probably look something
like
foreach ($resource->parts()) {
my $dateStatus = $resource->getDateStatus($_);
my $completionStatus = $resource->getCompletionStatus($_);
or
my $status = $resource->status($_);
... use it here ...
}
Which you use depends on exactly what you are looking for. The
status()
function has been optimized for the nav maps display and may
not precisely match what you need elsewhere.
The symbolic constants shown below can be accessed through the
resource object: $res-
OPEN>.
- getDateStatus($part):
($part defaults to 0). A convenience function that returns a symbolic
constant telling you about the date status of the part. The possible
return values are:
Date Codes
- getCompletionStatus($part):
($part defaults to 0.) A convenience function that returns a symbolic
constant telling you about the completion status of the part, with the
following possible results:
Completion Codes
Composite Status
Along with directly returning the date or completion status, the
resource object includes a convenience function status() that will
combine the two status tidbits into one composite status that can
represent the status of the resource as a whole. This method represents
the concept of the thing we want to display to the user on the nav maps
screen, which is a combination of completion and open status. The precise logic is
documented in the comments of the status method. The following results
may be returned, all available as methods on the resource object
($res->NETWORK_FAILURE): In addition to the return values that match
the date or completion status, this function can return ``ANSWER_SUBMITTED''
if that problemstatus parameter value is set to No, suppressing the
incorrect/correct feedback.
- NETWORK_FAILURE:
The network has failed and the information is not available.
- NOTHING_SET:
No dates have been set for this problem (part) at all. (Because only
certain parts of a multi-part problem may be assigned, this can not be
collapsed into ``open later'', as we do not know a given part will EVER
be opened. For single part, this is the same as ``OPEN_LATER''.)
- CORRECT:
For any reason at all, the part is considered correct.
- EXCUSED:
For any reason at all, the problem is excused.
- PAST_DUE_NO_ANSWER:
The problem is past due, not considered correct, and no answer date is
set.
- PAST_DUE_ANSWER_LATER:
The problem is past due, not considered correct, and an answer date in
the future is set.
- ANSWER_OPEN:
The problem is past due, not correct, and the answer is now available.
- OPEN_LATER:
The problem is not yet open.
- TRIES_LEFT:
The problem is open, has been tried, is not correct, but there are
tries left.
- INCORRECT:
The problem is open, and all tries have been used without getting the
correct answer.
- OPEN:
The item is open and not yet tried.
- ATTEMPTED:
The problem has been attempted.
- ANSWER_SUBMITTED:
An answer has been submitted, but the student should not see it.
Completable
The completable method represents the concept of whether the student can
currently do the problem. If the student can do the problem, which means
that it is open, there are tries left, and if the problem is manually graded
or the grade is suppressed via problemstatus, the student has not tried it
yet, then the method returns 1. Otherwise, it returns 0, to indicate that
either the student has tried it and there is no feedback, or that for
some reason it is no longer completable (not open yet, successfully completed,
out of tries, etc.). As an example, this is used as the filter for the
``Uncompleted Homework'' option for the nav maps.
If this does not quite meet your needs, do not fiddle with it (unless you are
fixing it to better match the student's conception of ``completable'' because
it's broken somehow)... make a new method.
- getNext():
Retreive an array of the possible next resources after this
one. Always returns an array, even in the one- or zero-element case.
- getPrevious():
Retreive an array of the possible previous resources from this
one. Always returns an array, even in the one- or zero-element case.