Oracle APEX Dynamic Action Type Plugin: Markdown

This Oracle APEX plugin uses the Stack Overflow JavaScript Markdown implementation to turn textareas into Markdown editors and convert Markdown formatted text into HTML.

Works with APEX versions 4.2.x and 5.x
Turns a standard APEX text area into a Markdown editor only by setting the form element class to markdown
- Live preview of the rendered text
- Supports the readonly mode of the textarea
Converts the content of all other non HTML form elements with a class markdown to HTML
Can be used on dynamic content like reports
Support for the following Markdown Extra extensions: tables, fenced code blocks, definition lists, footnotes, special attributes, SmartyPants, newlines and strikethrough à la GitHub
Support for the well known image substitution strings (also in lowercase) in the live preview: #image_prefix#, #app_images#, #workspace_images# and additionally #images#, which is configurable with a own image function
Syntax highlighting in code blocks with highlight.js
Custom preview container, which allows you to create a full screen side by side editor - for an example see the online demo app
Event to hook in own code after preview refresh (Preview Refreshed [Markdown], see also changelog 1.3.0 )
You can configure a pre and post conversion function (see also changelog 1.3.0)
Prints runtime statistics to the browser console when page is in debug mode

Installation

Download the latest release
Install the file plugin/markdown-apex-plugin-1.x.x.sql into your application
Optional for performance: copy the files under server to your webserver and correct the file prefix of the plugin to point to the files on your webserver

Whats Next?

APEX has its own Markdown implementation now. So this project is no longer maintained. It still works, but don't expect any major maintenance efforts.

How To Use

Install the plugin
On your page create a dynamic action on page load with the action Markdown [Plug-in]
Add the CSS class markdown to your text areas and other content, which should be converted
Optionally create per dynamic content (reports and other refreshable region types) an additional dynamic action on framework event After Refresh with selection type Region

Credits

I would like to say THANK YOU to all the people who share their knowledge. Without this sharing I would not have been able to create this Markdown plugin. Special thanks to John Gruber for his first Markdown implementation in Perl, to John Fraser for his JavaScript port and to Dana Robinson and the people of Stack Exchange Inc. for the modifications and bugfixes. See also the LICENSE.txt for more information.

How The Plugin Works

The plugin uses the triggering element of a dynamic action as a starting point to find elements with the class markdown
- Text areas are converted into Markdown editors
- The content of all other non form elements is rendered into HTML
A normal page setup consists of one dynamic action on Page Load with the action Markdown [Plug-in]
- The triggering element is the whole document
- The plugin will find all elements in the document with a class markdown
- Form elements except text areas are filtered out
  - You can write into HTML regions directly by wrapping your text into a span element <span class="markdown">Your text</span>
  - You can use display only items; they are rendered by the APEX engine as span elements - don't forget the class markdown
Optionally you have an additional dynamic action per report on framework event After Refresh with selection type Region
- The triggering element is your report region
- The plugin will find all elements in your report with a class markdown
- Please keep in mind that you can easily set the class in your report column
  - Interactive report: Column Formatting > HTML Expression
  - Classic report: Column Formatting > CSS Class or HTML Expression
- If you have only one report on a page, then it is ok to register only one dynamic action on report refresh and check the Fire On Page Load execution option

Options

The plugin options (most options are on application level) can be configured under Shared Components > User Interface > Component Settings > Markdown[Plugin].

You will find there the following options:

Custom Styles

You can add here custom styles for the rendered HTML.

Example: .markdown h1 { text-transform: uppercase; }

Custom Image Function

The Plugin will replace #images# with your configured custom image function.

Enable Sanitizing Converter

With this option two plugins are registered for the converter. One of them sanitizes the output HTML to only include a list of whitelisted HTML tags. The other one attempts to balance opening/closing tags to prevent leaking formating if the HTML is displayed in the browser.

Try To Use Original Value From Display Only Items

This option depends on the option Enable Sanitizing Converter.

The APEX engine does escape special characters in most cases. Sometimes you can disable this like in reports. For read only items you can't disable this and depending on your security settings of your application at a minimum the basic escaping is done.

If you have code blocks in your Markdown text with HTML inside, this could be very annoying, because all the < and > characters are escaped to HTML entities. In fact, your HTML code in code blocks looks very bad, when the item is rendered read only. The preview from the editor is ok, because it is a live preview in your browser without interaction of the APEX engine.

When you enable this plugin option, then the Markdown plugin try to use the original text from the hidden item to render your HTML. From the security side this should be ok, because you can enable this option only when you have also the sanitizer enabled, which does whitelisting of HTML tags and suppresses script tags. You can try this out by injecting javascript code - the converter will sort out the script tags and your code will appear as normal inline text.

Enable Syntax Highlighting In Code Blocks

The used syntax highlighter is highlight.js with the default set of 22 common languages: Apache, Bash, C#, C++, CSS, CoffeeScript, Diff, HTML-XML, HTTP, Ini, JSON, Java, JavaScript, Makefile, Markdown, Nginx, Objective-C, PHP, Perl, Python, Ruby, SQL.

If you need more or other languages (172 available) then you can create your custom highlight.js package, rename it to the same file name used in the plugin and upload it to the plugin files.

Enable Markdown Extra Syntax

Markdown Extra is one of the extensions available for Markdown. It was originally implemented in PHP. For more details see here and here. These Markdown Extra syntax enhancements are also available for the JavaScript based implementation used in this Oracle APEX plugin:

Tables
Fenced Code Blocks à la GitHub
Definiton Lists
Footnotes
Special Attributes
SmartyPants
Newlines à la GitHub
Strikethrough à la GitHub

See the next sections for details.

Tables

http://michelf.ca/projects/php-markdown/extra/#table

The following markdown...

| Item      | Value | Qty |
|-----------|------:|:---:|
| Computer  | $1600 |  5  |  
| Phone     |   $12 |  12 |
| *Pipe*    |    $1 | 234 |

...will render to this:

Item	Value	Qty
Computer	$1600	5
Phone	$12	12
Pipe	$1	234

Span-level markdown inside of table cells will also be converted.

Fenced Code Blocks

http://github.github.com/github-flavored-markdown/

Fenced code blocks are supported à la GitHub. This markdown...

```
var x = 2;
```

...will be transformed into:

<pre>
    <code>var x = 2;</code>
</pre>

If syntax highlighting is enabled, then you can specify the language like so...

```javascript
var x = 2;
```

...which would be converted to:

<pre>
    <code class="language-javascript hljs">var x = 2;</code>
</pre>

If you omit the language, the highlighter tries its best to find out the language. The used highlighter is highlight.js with the default set of 22 common languages: Apache, Bash, C#, C++, CSS, CoffeeScript, Diff, HTML-XML, HTTP, Ini, JSON, Java, JavaScript, Makefile, Markdown, Nginx, Objective-C, PHP, Perl, Python, Ruby, SQL.

If you need more or other languages (172 available) then you can create your highlight.js package, rename it to the same file name used in the plugin and upload it to the plugin files.

Definition Lists

http://michelf.ca/projects/php-markdown/extra/#def-list

Term 1
:   Definition 1

Term 2
:   This definition has a code block.

        code block

becomes:

<dl>
  <dt>Term 1</dt>
  <dd>
    Definition 1
  </dd>
  <dt>Term 2</dt>
  <dd>
    This definition has a code block.
    <pre><code>code block</code></pre>
  </dd>
</dl>

Definitions can contain both inline and block-level markdown.

Footnotes

https://github.com/fletcher/MultiMarkdown/blob/master/Documentation/MultiMarkdown%20User%27s%20Guide.md#footnotes

Here is a footnote[^footnote].

[^footnote]: Here is the *text* of the **footnote**.

becomes:

<p>Here is a footnote<a href="#fn:footnote" id="fnref:footnote" title="See footnote" class="footnote">1</a>.</p>

<div class="footnotes">
<hr>
<ol>
<li id="fn:footnote">Here is the <em>text</em> of the <strong>footnote</strong>. <a href="#fnref:footnote" title="Return to article" class="reversefootnote">↩</a></li>
</ol>
</div>

You need a blank line after each footnote text, like with paragraphs.

Special Attributes

http://michelf.ca/projects/php-markdown/extra/#spe-attr

You can add class and id attributes to headers and gfm fenced code blocks.

``` {#gfm-id .gfm-class}
var foo = bar;
```

## A Header {#header-id}

### Another One ### {#header-id .hclass}

Underlined  {#what}
==========

SmartyPants

http://daringfireball.net/projects/smartypants/

SmartyPants extension converts ASCII punctuation characters into "smart" typographic punctuation HTML entities. For example:

Single backticks : 'Isn't this fun?' → ‘Isn’t this fun?’

Quotes : "Isn't this fun?" → “Isn’t this fun?”

Dashes : This -- is an en-dash and this --- is an em-dash → This – is an en-dash and this — is an em-dash

Newlines

https://help.github.com/articles/github-flavored-markdown#newlines

Newlines à la GitHub (without the need of two white spaces):

Roses are red
Violets are blue

becomes:

<p>Roses are red<br/>
Violets are blue</p>

Strikethrough

https://help.github.com/articles/github-flavored-markdown#strikethrough

Strikethrough à la GitHub:

~~Mistaken text.~~

becomes:

<p><del>Mistaken text.</del></p>

Custom Preview Container

If you want to have a custom preview container instead of the one generated under your text area simply create anywhere on your page a display only item with the name of the text area (editor) and append _PREVIEW to the name.

For an example: If the name of your text area is P3_SAMPLE_MARKDOWN_EDITOR then you name your display only item P3_SAMPLE_MARKDOWN_EDITOR_PREVIEW. The plugin will find this item and use it automatically.

You can also create a container element in the region source of an HTML region with the id attribute set to the mentioned name. (e.g. <div id="P3_SAMPLE_MARKDOWN_EDITOR_PREVIEW"></div>) or you set the static ID of the region itself to this name.

In both cases you have to manage the conditional rendering of your preview container by yourself. If the text area (Markdown editor) can be displayed in read only mode, then the text area IS your (pre)view, because the Markdown plugin simply renders all items except text areas and inputs and you have to hide ore not to render your custom preview container - its useless without an editor...

There is a small helper function shipped with plugin to maximize page items. It depends on your theme, if this helper is working for your or not. If not, then simply modify the helper to your needs, as said - the helper function is really small - here an example call in a dynamic action - you can see this helper live in action in the online demo app:

markdown.maximizeItem('editor', '#P3_SAMPLE_MARKDOWN_EDITOR', 4, 100);
markdown.maximizeItem('preview', '#P3_SAMPLE_MARKDOWN_EDITOR_PREVIEW',2 , 78);

The function itself:

markdown.maximizeItem = function (itemType, selector, regionIsNthParent, offsetBottom, debug) {
    $(selector).each( function() {
        var item = $(this);
        // jQuery eq function start count with 0, we want start count with 1
        var region = item.parents().eq(regionIsNthParent -1);
        var maximizeEditor = function() {
            item.width( region.width() - parseInt(region.css('padding-left')) - parseInt(region.css('padding-right')) )
                .height( $(window).height() - item.offset().top - offsetBottom );
        };
        var maximizePreview = function() {
            region.css( 'overflow','auto' )
                .height( $(window).height() - region.offset().top - offsetBottom );
        };

        if (itemType === 'editor') maximizeEditor();
        else if (itemType === 'preview') maximizePreview();

        if (debug) region.css('border','1px solid red');
        else $(window).resize(function () {
            if (itemType === 'editor') maximizeEditor();
            else if (itemType === 'preview') maximizePreview();
        });
    });
};

Changelog

This Markdown plugin uses semantic versioning.

Please use for all comments and discussions the issues functionality on GitHub.

1.3.1 (2018-01-07)

Fixed: When content looks like a YAML header it is removed
- Parsing of a YAML header is now done conditional - you can set an config option per usage - the default is no YAML parsing

1.3.0 (2017-03-31)

Move sprite image wmd-buttons.png as data URI to the css file (this helps to move plugin files to a webserver without breaking the image - no relative paths possible under APEX 4.2)
Add class rendered to rendered elements to avoid double conversion
New dynamic action component event: Preview Refreshed [Markdown]
- This can be used to trigger some additional action on your page
- Attention: If you try to modify the rendered HTML in the preview directly after it was refreshed, then you will break the preview functionality; Please use for this cases the Post Conversion Function (see description below)
New option Pre Conversion Function: If you configure here a JavaScript function, this function will get in the first paramater the raw Markdown text and must return the modified Markdown text, which will be send then to the converter
- Example: function (text) { return "# Converted text follows\n\n" + text; /*add a level 1 header*/ }
New option Post Conversion Function: If you configure here a JavaScript function, this function will get in the first paramater the rendered HTML text and must return the modified HTML text, which will be send then to the preview container
- Example: function (text) { return text + "<br>\n**This is not bold, because it was added after the conversion**"; }
Update to highlight.js 9.9.0 with the default set of 22 common languages: Apache, Bash, C#, C++, CSS, CoffeeScript, Diff, HTML-XML, HTTP, Ini, JSON, Java, JavaScript, Makefile, Markdown, Nginx, Objective-C, PHP, Perl, Python, Ruby, SQL - if you need more or other languages (172 available) then you can create your own custom highlight.js package under highlightjs.org/download
Internal name change of created editors; You can now easily force the preview refresh after procedural changes of your text area content - simply call this JavaScript code: markdown.editors.normalizedIdOfYourItemOrTextArea.refreshPreview() (all characters anything else then a-z, A-Z, 0-9 and _ are converted to _)
Restructure source code repository to use Grunt as build tool

1.2.0 (not officially released):

Base support for YAML header - this comes from the demo app of my Markdown Reporter project and parses out the attributes title, author and date from a YAML header

1.1.1 (2016-02-15)

Fixed: Helper function to maximize editor item not working in IE

1.1.0 (2016-02-14)

Support for the following Markdown Extra extensions: tables, fenced code blocks, definition lists, footnotes, special attributes, SmartyPants, newlines and strikethrough à la GitHub
Support for the well known image substitution strings (also in lowercase) in the live preview: #image_prefix#, #app_images#, #workspace_images# and additionally #images#, which is configurable with a own image function
Syntax highlighting in code blocks with highlight.js and the default set of 23 common languages: Apache, Bash, C#, C++, CSS, CoffeeScript, Device Tree (*.dts), Diff, HTML-XML, HTTP, Ini, JSON, Java, JavaScript, Makefile, Markdown, Nginx, Objective-C, PHP, Perl, Python, Ruby, SQL - if you need more or other languages (146 available) then you can create your own custom highlight.js package
Custom preview container, which allows you to create a full screen side by side editor - for an example see the online demo app
Improved styling of code blocks and lists, inspired by DokuWiki
Improved security with a optional sanitizing converter (per default switched on), which only allows whitelisted HTML tags
All new options are configurable under Shared Components > User Interface > Component Settings > Markdown[Plugin]

1.0.0 (2016-01-01)

First public release

ogobrecht/markdown-apex-plugin

Oracle APEX Dynamic Action Type Plugin: Markdown

Installation

Whats Next?

How To Use

Links

Credits

How The Plugin Works

Options

Custom Styles

Custom Image Function

Enable Sanitizing Converter

Try To Use Original Value From Display Only Items

Enable Syntax Highlighting In Code Blocks

Enable Markdown Extra Syntax

Tables

Fenced Code Blocks

Definition Lists

Footnotes

Special Attributes

SmartyPants

Newlines

Strikethrough

Custom Preview Container

Changelog

1.3.1 (2018-01-07)

1.3.0 (2017-03-31)

1.2.0 (not officially released):

1.1.1 (2016-02-15)

1.1.0 (2016-02-14)

1.0.0 (2016-01-01)