tutorial-categories.adp
Delivered as text/html
Related Files
[ hide source ] | [ make this the default ]
File Contents
<property name="context">{/doc/acs-core-docs/ {ACS Core Documentation}} {Categories}</property> <property name="doc(title)">Categories</property> <master> <include src="/packages/acs-core-docs/lib/navheader" leftLink="tutorial-admin-pages" leftLabel="Prev" title=" Chapter 10. Advanced Topics" rightLink="profile-code" rightLabel="Next"> <div class="sect1"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> <a name="tutorial-categories" id="tutorial-categories"></a>Categories</h2></div></div></div><div class="authorblurb"> <p>extended by <a class="ulink" href="mailto:nima.mazloumi\@gmx.de" target="_top">Nima Mazloumi</a> </p> OpenACS docs are written by the named authors, and may be edited by OpenACS documentation staff.</div><p>You can associate any ACS Object with one or more categories. In this tutorial we'll show how to equip your application with user interface to take advantage of the Categories service.</p><p>We'll start by installing the Categories service. Go to <code class="computeroutput">/acs/admin</code> and install it. This step won't be necessary for the users of your applications because you'll create a dependency with the Package Manager which will take care that the Categories service always gets installed when your application gets installed.</p><p>Now that we have installed the Categories service we can proceed to modifying our application so that it can take advantage of it. We'll do it in three steps:</p><div class="orderedlist"><ol class="orderedlist" type="1"> <li class="listitem"> <p>The Categories service provides a mechanism to associate one or more <span class="emphasis"><em>category trees</em></span> that are relevant to your application. One example of such tree is a tree of geographical locations. Continents are on the top of such tree, each continent containing countries etc. Another tree might contain market segments etc. Before users of your application can take advantage of the Categories service there needs to be a way for administrators of your application to choose which category trees are applicable for the application.</p><p>The way to achieve this is to provide a link to the Category Management pages. Add the following snippet to your <code class="computeroutput">/var/lib/aolserver/<span class="replaceable"><span class="replaceable">$OPENACS_SERVICE_NAME</span></span>/packages/myfirstpackage/www/admin/index.tcl</code> file:</p><pre class="programlisting"> set category_map_url [export_vars -base "[site_node::get_package_url -package_key categories]cadmin/one-object" { { object_id $package_id } }] </pre><p>and the following snippet to your <code class="computeroutput">/var/lib/aolserver/<span class="replaceable"><span class="replaceable">$OPENACS_SERVICE_NAME</span></span>/packages/myfirstpackage/www/admin/index.adp</code> file:</p><pre class="programlisting"> <a href="\@category_map_url\@">#categories.Site_wide_Categories#</a> </pre><p>The link created by the above code (<code class="computeroutput">category_map_url</code>) will take the admin to the generic admin UI where he can pick category trees that make sense for this application. The same UI also includes facilities to build and edit category trees. Notice that the only parameter in this example is <code class="computeroutput">package_id</code> so that category trees will be associated with the object identified by this <code class="computeroutput">package_id</code>. The categorization service is actually more general than that: instead of <code class="computeroutput">package_id</code> you could use an ID of some other object that serves as a "container" in your application. For example, if your discussion forums application supports multiple forums you would use <code class="computeroutput">forum_id</code> to associate category trees with just that one forum rather than the entire application instance.</p> </li><li class="listitem"> <p>Once the category trees have been selected users need a way to categorize items. The easiest way to do this is by adding the <code class="computeroutput">category</code> widget type of the form builder to <code class="computeroutput">note-edit.tcl</code>. To achieve this we'll need to use the <code class="computeroutput">-extend</code> switch to the <code class="computeroutput">ad_form</code> command. Here's the "meat" of the <code class="computeroutput">note-edit.tcl</code> page:</p><pre class="programlisting"> # extend the form to support categories set package_id [ad_conn package_id] category::ad_form::add_widgets -form_name note -container_object_id $package_id -categorized_object_id [expr {[info exists item_id] ? $item_id : ""}] ad_form -extend -name note -on_submit { set category_ids [category::ad_form::get_categories -container_object_id $package_id] } -new_data { .... category::map_object -remove_old -object_id $item_id $category_ids } -edit_data { .... category::map_object -remove_old -object_id $item_id $category_ids } -after_submit { ad_returnredirect "." ad_script_abort } </pre><p>While the <code class="computeroutput">category::ad_form::add_widgets</code> proc is taking care to extend your form with associated categories you need to ensure that your items are mapped to the corresponding category object yourself.</p><p> <code class="computeroutput">note-edit.tcl</code> requires a <code class="computeroutput">note_id</code> to determine which record should be deleted. It also looks for a confirmation variable, which should initially be absert. If it is absent, we create a form to allow the user to confirm the deletion. Note that in <code class="computeroutput">entry-edit.tcl</code> we used <code class="computeroutput">ad_form</code> to access the Form Template commands; here, we call them directly because we don't need the extra features of ad_form. The form calls itself, but with hidden variables carrying both <code class="computeroutput">note_id</code> and <code class="computeroutput">confirm_p</code>. If confirm_p is present, we delete the record, set redirection back to the index, and abort script execution.</p><p>The database commands:</p><pre class="screen"> [$OPENACS_SERVICE_NAME\@yourserver www]$ <strong class="userinput"><code>emacs note-delete.xql</code></strong> </pre><pre class="programlisting"> <?xml version="1.0"?> <queryset> <fullquery name="do_delete"> <querytext> select samplenote__delete(:note_id) </querytext> </fullquery> <fullquery name="get_name"> <querytext> select samplenote__name(:note_id) </querytext> </fullquery> </queryset> </pre><p>And the adp page:</p><pre class="screen"> [$OPENACS_SERVICE_NAME\@yourserver www]$ <strong class="userinput"><code>emacs note-delete.adp</code></strong> </pre><pre class="programlisting"> <master> <property name="title">\@title\@</property> <property name="context">{\@title\@}</property> <h2>\@title\@</h2> <formtemplate id="note-del-confirm"></formtemplate> </form> </pre><p>The ADP is very simple. The <code class="computeroutput">formtemplate</code> tag outputs the HTML form generated by the ad_form command with the matching name. Test it by adding the new files in the APM and then deleting a few samplenotes.</p> </li><li class="listitem"> <p>We will now make categories optional on package instance level and also add a configuration page to allow the package admin to enable/disable categories for his package.</p><p>Go to the APM and create a number parameter with the name "<code class="computeroutput">EnableCategoriesP</code>" and the default value "<code class="computeroutput">0</code>".</p><p>Add the following lines to your <code class="computeroutput">index.tcl</code>:</p><pre class="programlisting"> set return_url [ns_conn url] set use_categories_p [parameter::get -parameter "EnableCategoriesP"] </pre><p>Change your to this:</p><pre class="programlisting"> <a href=configure?<%=[export_vars -url {return_url}]%>>Configure</a> <if \@use_categories_p\@> <a href="\@category_map_url\@">#categories.Site_wide_Categories#</a> </if> </pre><p>Now create a configure page</p><pre class="programlisting"> ad_page_contract { This page allows an admin to change the categories usage mode. } { {return_url ""} } set title "Configure category mode" set context [list $title] set use_categories_p [parameter::get -parameter "EnableCategoriesP"] ad_form -name categories_mode -form { {enabled_p:text(radio) {label "Enable Categories"} {options {{Yes 1} {No 0}}} {value $use_categories_p} } {return_url:text(hidden) {value $return_url}} {submit:text(submit) {label "Set Mode"}} } -on_submit { parameter::set_value -parameter "EnableCategoriesP" -value $enabled_p if {$return_url ne ""} { ns_returnredirect $return_url } } </pre><p>and add this to its corresponding ADP page</p><pre class="programlisting"> <master> <property name="title">\@title\@</property> <property name="context">\@context\@</property> <formtemplate id="categories_mode"></formtemplate> </pre><p>Reference this page from your admin page</p><pre class="programlisting"> #TCL: set return_url [ad_conn url] #ADP: <a href=configure?<%=[export_vars -url {return_url}]%>>Configure</a> </pre><p>Change the <code class="computeroutput">note-edit.tcl</code>:</p><pre class="programlisting"> # Use Categories? set use_categories_p [parameter::get -parameter "EnableCategoriesP" -default 0] if { $use_categories_p == 1 } { # YOUR NEW FORM DEFINITION } else { # YOUR OLD FORM DEFINITION } </pre> </li><li class="listitem"> <p>You can filter your notes using categories. The below example does not support multiple filters and displays a category in a flat format.</p><p>The first step is to define the optional parameter <code class="computeroutput">category_id</code> for <code class="computeroutput">index.tcl</code>:</p><pre class="programlisting"> ad_page_contract { YOUR TEXT } { YOURPARAMS {category_id:integer,optional {}} } </pre><p>Now you have to check whether categories are enabled or not. If this is the case and a category id is passed you need to extend your sql select query to support filtering. One way would be to extend the <code class="computeroutput">mfp::note::get</code> proc to support two more swiches <code class="computeroutput">-where_clause</code> and <code class="computeroutput">-from_clause</code>.</p><pre class="programlisting"> set use_categories_p [parameter::get -parameter "EnableCategoriesP" -default 0] if { $use_categories_p == 1 && $category_id ne "" } { set from_clause "category_object_map com" set_where_clause "com.object_id = qa.entry_id and com.category_id = :category_id" ... mfp::note::get \ -item_id $item_id \ -array note_array \ -where_clause $where_clause \ -from_clause $from_clause ... } else { # OLD STUFF } </pre><p>Also you need to make sure that the user can see the corresponding categories. Add the following snippet to the end of your index page:</p><pre class="programlisting"> # Site-Wide Categories if { $use_categories_p == 1} { set package_url [ad_conn package_url] if { $category_id ne "" } { set category_name [category::get_name $category_id] if { $category_name eq "" } { ad_return_exception_page 404 "No such category" "Site-wide \ Category with ID $category_id doesn't exist" return } # Show Category in context bar append context_base_url /cat/$category_id lappend context [list $context_base_url $category_name] set type "all" } # Cut the URL off the last item in the context bar if { [llength $context] > 0 } { set context [lreplace $context end end [lindex $context end end]] } db_multirow -unclobber -extend { category_name tree_name } categories categories { select c.category_id as category_id, c.tree_id from categories c, category_tree_map ctm where ctm.tree_id = c.tree_id and ctm.object_id = :package_id } { set category_name [category::get_name $category_id] set tree_name [category_tree::get_name $tree_id] } } </pre><p>and to the corresponding index ADP page:</p><pre class="programlisting"> <if \@use_categories_p\@> <multiple name="categories"> <h2>\@categories.tree_name\@ <group column="tree_id"> <a href="\@package_url\@cat/\@categories.category_id\@?\@YOURPARAMS\@&category_id=\@categories.category_id\@">\@categories.category_name\@ </group> </multiple> <a href="\@package_url\@view?\@YOURPARAMS\@">All Items</if> </pre><p>Finally you need an <code class="computeroutput">index.vuh</code> in your www folder to rewrite the URLs correctly, <a class="xref" href="tutorial-vuh" title="Using .vuh files for pretty URLs">the section called “Using .vuh files for pretty URLs”</a>:</p><pre class="programlisting"> set url /[ad_conn extra_url] if {[regexp {^/+cat/+([^/]+)/*} $url ignore_whole category_id]} { rp_form_put category_id $category_id } rp_internal_redirect "/packages/YOURPACKAGE/www/index" </pre><p>Now when ever the user select a category only notes that belong to this category are displayed.</p> </li> </ol></div> </div> <include src="/packages/acs-core-docs/lib/navfooter" leftLink="tutorial-admin-pages" leftLabel="Prev" leftTitle="Admin Pages" rightLink="profile-code" rightLabel="Next" rightTitle="Profile your code" homeLink="index" homeLabel="Home" upLink="tutorial-advanced" upLabel="Up">