[[!template id=plugin name=report author="[[rubykat]]"]]
[[!tag type/meta type/format]]
[[!toc]]
## NAME

IkiWiki::Plugin::report - Produce templated reports from page field data.

## SYNOPSIS

    # activate the plugin
    add_plugins => [qw{goodstuff report ....}],

    \[[!report template="blog_summary"
    pages="blog/*"
    sort="mtime"]]

## DESCRIPTION

This plugin provides the **report** directive.  This enables one to report on
the structured data ("field" values) of multiple pages; the output is formatted
via a template.  This depends on the "field" plugin.

The pages to report on are selected by a PageSpec given by the "pages"
parameter.  The template is given by the "template" parameter.
The template expects the data from a single page; it is applied
to each matching page separately, one after the other.

Additional parameters can be used to fill out the template, in
addition to the "field" values.  Passed-in values override the
"field" values.

There are two places where template files can live.  One, as with the
[[plugins/template]] plugin, is in the /templates directory on the wiki.  These
templates are wiki pages, and can be edited from the web like other wiki
pages.

The second place where template files can live is in the global
templates directory (the same place where the page.tmpl template lives).
This is a useful place to put template files if you want to prevent
them being edited from the web, and you don't want to have to make
them work as wiki pages.

## OPTIONS

**template**: The template to use for the report.

**pages**: A PageSpec to determine the pages to report on.

**sort**: How the matching pages should be sorted.  Sorting criteria are separated by spaces.

The possible values for sorting are:

* **page**: Sort by the full page ID.
* **pagename**: Sort by the base page name.
* **pagename_natural**: Sort by the base page name, using Sort::Naturally if it is installed.
* **mtime**: Sort by the page modification time.
* **age**: Sort by the page creation time, newest first.

Any other value is taken to be a field name to sort by.
If a sort value begins with a minus (-) then the order for that field is reversed.

### Headers

An additional option is the "headers" option.  This is a space-separated
list of field names which are to be used as headers in the report.  This
is a way of getting around one of the limitations of HTML::Template, that
is, not being able to do tests such as
"if this-header is not equal to previous-header".

Instead, that logic is performed inside the plugin.  The template is
given parameters "HEADER1", "HEADER2" and so on, for each header.
If the value of a header field is the same as the previous value,
then HEADER**N** is set to be empty, but if the value of the header
field is new, then HEADER**N** is given that value.

#### Example

Suppose you're writing a blog in which you record "moods", and you
want to display your blog posts by mood.

    \[[!report template="mood_summary"
    pages="blog/*"
    sort="Mood Date title"
    headers="Mood"]]

The "mood_summary" template might be like this:

    <TMPL_IF NAME="HEADER1">
    ## <TMPL_VAR NAME="HEADER1">
    </TMPL_IF>
    ### <TMPL_VAR NAME="TITLE">
    (<TMPL_VAR NAME="DATE">) \[[<TMPL_VAR NAME="PAGE"]]
    <TMPL_VAR NAME="DESCRIPTION">
    
### Advanced Options

The following options are used to improve efficiency when dealing
with large numbers of pages; most people probably won't need them.

**trail**:

A page or pages to use as a "trail" page.  When a trail page is used,
the matching pages are limited to (a subset of) the pages which that
page links to; the "pages" pagespec in this case, rather than selecting
pages from the entire wiki, will select pages from within the set of pages
given by the trail page.

**doscan**:

Whether this report should be called in "scan" mode; if it is, then
the pages which match the pagespec are added to the list of links from
this page.  This can be used by *another* report by setting this
page to be a "trail" page in *that* report.
It is not possible to use "trail" and "doscan" at the same time.
By default, "doscan" is false.

## TEMPLATE PARAMETERS

The templates are in HTML::Template format, just as [[plugins/template]] and
[[ftemplate]] are.  The parameters passed in to the template are as follows:

***fields***:

The structured data from the current matching page.  This includes
"title" and "description" if they are defined.

***common values***:

Values known for all pages: "page", "destpage".  Also "basename" (the base name of the page).

***passed-in values***:

Any additional parameters to the report directive are passed to the
template; a parameter will override the matching "field" value.
For example, if you have a "Mood" field, and you pass Mood="bad" to
the report, then that will be the Mood which is given for the whole
report.

Generally this is useful if one wishes to make a more generic
template and hide or show portions of it depending on what
values are passed in the report directive call.

For example, one could have a "hide_mood" parameter which would hide
the "Mood" section of your template when it is true, which one could
use when the Mood is one of the headers.

***headers***:

See the section on Headers.

***first and last***:

If this is the first page-record in the report, then "first" is true.
If this is the last page-record in the report, then "last" is true.

## PREREQUISITES

    IkiWiki
    IkiWiki::Plugin::field
    HTML::Template
    Encode

## DOWNLOAD

* browse at GitHub: <http://github.com/rubykat/ikiplugins/blob/master/IkiWiki/Plugin/report.pm>
* git repo at git://github.com/rubykat/ikiplugins.git