From 53ed6d7d1e678d7486337ce67a2f17b30bac21ac Mon Sep 17 00:00:00 2001
From: nodiscc <nodiscc@gmail.com>
Date: Thu, 26 Jan 2017 18:52:54 +0100
Subject: Generate HTML documentation using MkDocs (WIP)

MkDocs is a static site generator geared towards building project documentation.
Documentation source files are written in Markdown, and configured with a single YAML file.

 * http://www.mkdocs.org/
 * http://www.mkdocs.org/user-guide/configuration/

Ref. #312

* remove pandoc-generated HTML documentation
* move markdown doc to doc/md/,
* mkdocs.yml:
  * generate HTML doc in doc/html
  * add pages TOC/ordering
  * use index.md as index page
* Makefile: remove execute permissions from generated files
* Makefile: rewrite htmlpages GFM to markdown conversion using sed:
   awk expression aslo matched '][' which causes invalid output on complex links with images or code blocks
* Add mkdocs.yml to .gitattributes, exclude this file from release archives
* Makefile: rename: htmldoc -> doc_html target
* run make doc: pull latest markdown documentation from wiki
* run make htmlpages: update html documentation
---
 doc/md/Plugin-System.md | 710 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 710 insertions(+)
 create mode 100644 doc/md/Plugin-System.md

(limited to 'doc/md/Plugin-System.md')

diff --git a/doc/md/Plugin-System.md b/doc/md/Plugin-System.md
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@@ -0,0 +1,710 @@
+[**I am a developer.** Developer API.](#developer-api)
+
+[**I am a template designer.** Guide for template designer.](#guide-for-template-designer)
+
+## Developer API
+
+### What can I do with plugins?
+
+The plugin system let you:
+
+  * insert content into specific places across templates.
+  * alter data before templates rendering.
+  * alter data before saving new links.
+
+### How can I create a plugin for Shaarli?
+
+First, chose a plugin name, such as `demo_plugin`.
+
+Under `plugin` folder, create a folder named with your plugin name. Then create a <plugin_name>.php file in that folder.
+
+You should have the following tree view:
+
+```
+| index.php
+| plugins/
+|---| demo_plugin/
+|   |---| demo_plugin.php
+```
+
+### Plugin initialization
+
+At the beginning of Shaarli execution, all enabled plugins are loaded. At this point, the plugin system looks for an `init()` function to execute and run it if it exists. This function must be named this way, and takes the `ConfigManager` as parameter.
+
+    <plugin_name>_init($conf)
+
+This function can be used to create initial data, load default settings, etc. But also to set *plugin errors*. If the initialization function returns an array of strings, they will be understand as errors, and displayed in the header to logged in users.
+
+### Understanding hooks
+
+A plugin is a set of functions. Each function will be triggered by the plugin system at certain point in Shaarli execution.
+
+These functions need to be named with this pattern:
+
+```
+hook_<plugin_name>_<hook_name>($data, $conf)
+```
+
+Parameters:
+
+  - data: see [$data section](https://github.com/shaarli/Shaarli/wiki/Plugin-System#plugins-data)
+  - conf: the `ConfigManager` instance.
+
+For exemple, if my plugin want to add data to the header, this function is needed:
+
+    hook_demo_plugin_render_header
+
+If this function is declared, and the plugin enabled, it will be called every time Shaarli is rendering the header.
+
+### Plugin's data
+
+#### Parameters
+
+Every hook function has a `$data` parameter. Its content differs for each hooks.
+
+**This parameter needs to be returned every time**, otherwise data is lost.
+
+    return $data;
+
+#### Filling templates placeholder
+
+Template placeholders are displayed in template in specific places.
+
+RainTPL displays every element contained in the placeholder's array. These element can be added by plugins.
+
+For example, let's add a value in the placeholder `top_placeholder` which is displayed at the top of my page:
+
+```php
+$data['top_placeholder'][] = 'My content';
+# OR
+array_push($data['top_placeholder'], 'My', 'content');
+
+return $data;
+```
+
+#### Data manipulation
+
+When a page is displayed, every variable send to the template engine is passed to plugins before that in `$data`.
+
+The data contained by this array can be altered before template rendering.
+
+For exemple, in linklist, it is possible to alter every title:
+
+```php
+// mind the reference if you want $data to be altered
+foreach ($data['links'] as &$value) {
+    // String reverse every title.
+    $value['title'] = strrev($value['title']);
+}
+
+return $data;
+```
+
+### Metadata
+
+Every plugin needs a `<plugin_name>.meta` file, which is in fact an `.ini` file (`KEY="VALUE"`), to be listed in plugin administration.
+
+Each file contain two keys:
+
+  * `description`: plugin description
+  * `parameters`: user parameter names, separated by a `;`.
+  * `parameter.<PARAMETER_NAME>`: add a text description the specified parameter.
+
+> Note: In PHP, `parse_ini_file()` seems to want strings to be between by quotes `"` in the ini file.
+
+### It's not working!
+
+Use `demo_plugin` as a functional example. It covers most of the plugin system features.
+
+If it's still not working, please [open an issue](https://github.com/shaarli/Shaarli/issues/new).
+
+### Hooks
+
+| Hooks         | Description   |
+| ------------- |:-------------:|
+| [render_header](#render_header) | Allow plugin to add content in page headers. |
+| [render_includes](#render_includes) | Allow plugin to include their own CSS files. |
+| [render_footer](#render_footer) | Allow plugin to add content in page footer and include their own JS files. | 
+| [render_linklist](#render_linklist) | It allows to add content at the begining and end of the page, after every link displayed and to alter link data. |
+| [render_editlink](#render_editlink) |  Allow to add fields in the form, or display elements. |
+| [render_tools](#render_tools) |  Allow to add content at the end of the page. |
+| [render_picwall](#render_picwall) |  Allow to add content at the top and bottom of the page. |
+| [render_tagcloud](#render_tagcloud) |  Allow to add content at the top and bottom of the page, and after all tags. |
+| [render_taglist](#render_taglist) |  Allow to add content at the top and bottom of the page, and after all tags. |
+| [render_daily](#render_daily) |  Allow to add content at the top and bottom of the page, the bottom of each link and to alter data. |
+| [render_feed](#render_feed) | Allow to do add tags in RSS and ATOM feeds. |
+| [save_link](#save_link) | Allow to alter the link being saved in the datastore. |
+| [delete_link](#delete_link) | Allow to do an action before a link is deleted from the datastore. |
+
+
+
+#### render_header
+
+Triggered on every page.
+
+Allow plugin to add content in page headers.
+
+##### Data
+
+`$data` is an array containing:
+
+  * `_PAGE_`: current target page (eg: `linklist`, `picwall`, etc.).
+  * `_LOGGEDIN_`: true if user is logged in, false otherwise.
+
+##### Template placeholders
+
+Items can be displayed in templates by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `buttons_toolbar`: after the list of buttons in the header.
+
+![buttons_toolbar_example](http://i.imgur.com/ssJUOrt.png)
+
+  * `fields_toolbar`: after search fields in the header.
+
+> Note: This will only be called in linklist.
+
+![fields_toolbar_example](http://i.imgur.com/3GMifI2.png)
+
+#### render_includes
+
+Triggered on every page.
+
+Allow plugin to include their own CSS files.
+
+##### Data
+
+`$data` is an array containing:
+
+  * `_PAGE_`: current target page (eg: `linklist`, `picwall`, etc.).
+  * `_LOGGEDIN_`: true if user is logged in, false otherwise.
+
+##### Template placeholders
+
+Items can be displayed in templates by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `css_files`: called after loading default CSS.
+
+> Note: only add the path of the CSS file. E.g: `plugins/demo_plugin/custom_demo.css`.
+
+#### render_footer
+
+Triggered on every page.
+
+Allow plugin to add content in page footer and include their own JS files.
+
+##### Data
+
+`$data` is an array containing:
+
+  * `_PAGE_`: current target page (eg: `linklist`, `picwall`, etc.).
+  * `_LOGGEDIN_`: true if user is logged in, false otherwise.
+
+##### Template placeholders
+
+Items can be displayed in templates by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `text`: called after the end of the footer text.
+  * `endofpage`: called at the end of the page.
+
+![text_example](http://i.imgur.com/L5S2YEH.png)
+
+  * `js_files`: called at the end of the page, to include custom JS scripts.
+
+> Note: only add the path of the JS file. E.g: `plugins/demo_plugin/custom_demo.js`.
+
+#### render_linklist
+
+Triggered when `linklist` is displayed (list of links, permalink, search, tag filtered, etc.).
+
+It allows to add content at the begining and end of the page, after every link displayed and to alter link data.
+
+##### Data
+
+`$data` is an array containing:
+
+  * `_LOGGEDIN_`: true if user is logged in, false otherwise.
+  * All templates data, including links.
+
+##### Template placeholders
+
+Items can be displayed in templates by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `action_plugin`: next to the button "private only" at the top and bottom of the page.
+
+![action_plugin_example](http://i.imgur.com/Q12PWg0.png)
+
+  * `link_plugin`: for every link, between permalink and link URL.
+
+![link_plugin_example](http://i.imgur.com/3oDPhWx.png)
+
+  * `plugin_start_zone`: before displaying the template content.
+
+![plugin_start_zone_example](http://i.imgur.com/OVBkGy3.png)
+
+  * `plugin_end_zone`: after displaying the template content.
+
+![plugin_end_zone_example](http://i.imgur.com/6IoRuop.png)
+
+#### render_editlink
+
+Triggered when the link edition form is displayed.
+
+Allow to add fields in the form, or display elements.
+
+##### Data
+
+`$data` is an array containing:
+
+  * All templates data.
+
+##### Template placeholders
+
+Items can be displayed in templates by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `edit_link_plugin`: after tags field.
+
+![edit_link_plugin_example](http://i.imgur.com/5u17Ens.png)
+
+#### render_tools
+
+Triggered when the "tools" page is displayed.
+
+Allow to add content at the end of the page.
+
+##### Data
+
+`$data` is an array containing:
+
+  * All templates data.
+
+##### Template placeholders
+
+Items can be displayed in templates by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `tools_plugin`: at the end of the page.
+
+![tools_plugin_example](http://i.imgur.com/Bqhu9oQ.png)
+
+#### render_picwall
+
+Triggered when picwall is displayed.
+
+Allow to add content at the top and bottom of the page.
+
+##### Data
+
+`$data` is an array containing:
+
+  * `_LOGGEDIN_`: true if user is logged in, false otherwise.
+  * All templates data.
+
+##### Template placeholders
+
+Items can be displayed in templates by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `plugin_start_zone`: before displaying the template content.
+
+  * `plugin_end_zone`: after displaying the template content.
+
+![plugin_start_end_zone_example](http://i.imgur.com/tVTQFER.png)
+
+#### render_tagcloud
+
+Triggered when tagcloud is displayed.
+
+Allow to add content at the top and bottom of the page.
+
+##### Data
+
+`$data` is an array containing:
+
+  * `_LOGGEDIN_`: true if user is logged in, false otherwise.
+  * All templates data.
+
+##### Template placeholders
+
+Items can be displayed in templates by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `plugin_start_zone`: before displaying the template content.
+
+  * `plugin_end_zone`: after displaying the template content.
+
+For each tag, the following placeholder can be used:
+
+  * `tag_plugin`: after each tag
+
+![plugin_start_end_zone_example](http://i.imgur.com/vHmyT3a.png)
+
+
+#### render_taglist
+
+Triggered when taglist is displayed.
+
+Allow to add content at the top and bottom of the page.
+
+##### Data
+
+`$data` is an array containing:
+
+  * `_LOGGEDIN_`: true if user is logged in, false otherwise.
+  * All templates data.
+
+##### Template placeholders
+
+Items can be displayed in templates by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `plugin_start_zone`: before displaying the template content.
+
+  * `plugin_end_zone`: after displaying the template content.
+
+For each tag, the following placeholder can be used:
+
+  * `tag_plugin`: after each tag
+
+#### render_daily
+
+Triggered when tagcloud is displayed.
+
+Allow to add content at the top and bottom of the page, the bottom of each link and to alter data.
+
+##### Data
+
+`$data` is an array containing:
+
+  * `_LOGGEDIN_`: true if user is logged in, false otherwise.
+  * All templates data, including links.
+
+##### Template placeholders
+
+Items can be displayed in templates by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `link_plugin`: used at bottom of each link.
+
+![link_plugin_example](http://i.imgur.com/hzhMfSZ.png)
+
+  * `plugin_start_zone`: before displaying the template content.
+
+  * `plugin_end_zone`: after displaying the template content.
+
+#### render_feed
+
+Triggered when the ATOM or RSS feed is displayed.
+
+Allow to add tags in the feed, either in the header or for each items. Items (links) can also be altered before being rendered.
+
+##### Data
+
+`$data` is an array containing:
+
+  * `_LOGGEDIN_`: true if user is logged in, false otherwise.
+  * `_PAGE_`: containing either `rss` or `atom`.
+  * All templates data, including links.
+
+##### Template placeholders
+
+Tags can be added in feeds by adding an entry in `$data['<placeholder>']` array.
+
+List of placeholders:
+
+  * `feed_plugins_header`: used as a header tag in the feed.
+
+For each links:
+
+  * `feed_plugins`: additional tag for every link entry.
+
+#### save_link
+
+Triggered when a link is save (new link or edit).
+
+Allow to alter the link being saved in the datastore.
+
+##### Data
+
+`$data` is an array containing the link being saved:
+
+  * id
+  * title
+  * url
+  * shorturl
+  * description
+  * private
+  * tags
+  * created
+  * updated
+
+
+#### delete_link
+
+Triggered when a link is deleted.
+
+Allow to execute any action before the link is actually removed from the datastore
+
+##### Data
+
+`$data` is an array containing the link being saved:
+
+  * id
+  * title
+  * url
+  * shorturl
+  * description
+  * private
+  * tags
+  * created
+  * updated
+
+## Guide for template designer
+
+### Plugin administration
+
+Your theme must include a plugin administration page: `pluginsadmin.html`.
+
+> Note: repo's template link needs to be added when the PR is merged.
+
+Use the default one as an example.
+
+Aside from classic RainTPL loops, plugins order is handle by JavaScript. You can just include `plugin_admin.js`, only if:
+
+  * you're using a table.
+  * you call orderUp() and orderUp() onclick on arrows.
+  * you add data-line and data-order to your rows.
+
+Otherwise, you can use your own JS as long as this field is send by the form:
+
+<input type="hidden" name="order_{$key}" value="{$counter}">
+
+### Placeholder system
+
+In order to make plugins work with every custom themes, you need to add variable placeholder in your templates. 
+
+It's a RainTPL loop like this:
+
+    {loop="$plugin_variable"}
+        {$value}
+    {/loop}
+
+You should enable `demo_plugin` for testing purpose, since it uses every placeholder available.
+
+### List of placeholders
+
+**page.header.html**
+
+At the end of the menu:
+
+    {loop="$plugins_header.buttons_toolbar"}
+        {$value}
+    {/loop}
+
+At the end of file, before clearing floating blocks:
+
+    {if="!empty($plugin_errors) && isLoggedIn()"}
+        <ul class="errors">
+            {loop="plugin_errors"}
+                <li>{$value}</li>
+            {/loop}
+        </ul>
+    {/if}
+
+**includes.html**
+
+At the end of the file:
+
+```html
+{loop="$plugins_includes.css_files"}
+<link type="text/css" rel="stylesheet" href="{$value}#"/>
+{/loop}
+```
+
+**page.footer.html**
+
+At the end of your footer notes:
+
+```html
+{loop="$plugins_footer.text"}
+     {$value}
+{/loop}
+```
+
+At the end of file:
+
+```html
+{loop="$plugins_footer.js_files"}
+     <script src="{$value}#"></script>
+{/loop}
+```
+
+**linklist.html**
+
+After search fields:
+
+```html
+{loop="$plugins_header.fields_toolbar"}
+     {$value}
+{/loop}
+```
+
+Before displaying the link list (after paging):
+
+```html
+{loop="$plugin_start_zone"}
+     {$value}
+{/loop}
+```
+
+For every links (icons):
+
+```html
+{loop="$value.link_plugin"}
+    <span>{$value}</span>
+{/loop}
+```
+
+Before end paging:
+
+```html
+{loop="$plugin_end_zone"}
+     {$value}
+{/loop}
+```
+
+**linklist.paging.html**
+
+After the "private only" icon:
+
+```html
+{loop="$action_plugin"}
+     {$value}
+{/loop}
+```
+
+**editlink.html**
+
+After tags field:
+
+```html
+{loop="$edit_link_plugin"}
+     {$value}
+{/loop}
+```
+
+**tools.html**
+
+After the last tool:
+
+```html
+{loop="$tools_plugin"}
+     {$value}
+{/loop}
+```
+
+**picwall.html**
+
+Top:
+
+```html
+<div id="plugin_zone_start_picwall" class="plugin_zone">
+    {loop="$plugin_start_zone"}
+        {$value}
+    {/loop}
+</div>
+```
+
+Bottom:
+
+```html
+<div id="plugin_zone_end_picwall" class="plugin_zone">
+    {loop="$plugin_end_zone"}
+        {$value}
+    {/loop}
+</div>
+```
+
+**tagcloud.html**
+
+Top:
+
+```html
+   <div id="plugin_zone_start_tagcloud" class="plugin_zone">
+        {loop="$plugin_start_zone"}
+            {$value}
+        {/loop}
+    </div>
+```
+
+Bottom:
+
+```html
+    <div id="plugin_zone_end_tagcloud" class="plugin_zone">
+        {loop="$plugin_end_zone"}
+            {$value}
+        {/loop}
+    </div>
+```
+
+**daily.html**
+
+Top:
+
+```html
+<div id="plugin_zone_start_picwall" class="plugin_zone">
+     {loop="$plugin_start_zone"}
+         {$value}
+     {/loop}
+</div>
+```
+
+After every link:
+
+```html
+<div class="dailyEntryFooter">
+     {loop="$link.link_plugin"}
+          {$value}
+     {/loop}
+</div>
+```
+
+Bottom:
+
+```html
+<div id="plugin_zone_end_picwall" class="plugin_zone">
+    {loop="$plugin_end_zone"}
+        {$value}
+    {/loop}
+</div>
+```
+
+**feed.atom.xml** and **feed.rss.xml**:
+
+In headers tags section:
+```xml
+{loop="$feed_plugins_header"}
+  {$value}
+{/loop}
+```
+
+After each entry:
+```xml
+{loop="$value.feed_plugins"}
+  {$value}
+{/loop}
+```
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