ELPX Format Documentation (content.xml)¶

This document describes the modern .elpx file format used by eXeLearning v3+. It covers the ZIP structure, the content.xml ODE 2.0 schema, all element types, and an annotated example.

See also: For the legacy .elp format used by eXeLearning 2.x, see Legacy ELP Format (contentv3.xml).

Overview¶

An .elpx file is a ZIP archive that contains a complete, self-contained eXeLearning project. It was introduced in eXeLearning v3.0 as a replacement for the legacy .elp format. The key difference is that .elpx includes both:

A content.xml file in ODE 2.0 XML format (re-importable project structure)
Pre-rendered HTML output (viewable without importing)

This dual nature makes .elpx the recommended exchange format: it is human-readable in a browser and re-importable for editing.

ZIP Structure¶

project.elpx (ZIP)
├── content.xml               # ODE 2.0 project structure (re-importable)
├── content.dtd               # DTD for XML validation
├── index.html                # Entry point (first page rendered as HTML)
├── html/
│   ├── page-title.html       # Additional pages (one file per page)
│   └── ...
├── content/
│   ├── css/
│   │   └── base.css          # Base stylesheet
│   └── resources/
│       ├── image.jpg         # Project assets (images, PDFs, media)
│       └── ...
├── libs/
│   ├── common_i18n.js        # Localized strings
│   └── ...                   # jQuery, Bootstrap, and other libraries
├── theme/
│   ├── style.css             # Theme stylesheet
│   ├── style.js              # Theme JavaScript
│   └── ...
├── idevices/
│   ├── text/                 # Per-iDevice CSS/JS assets
│   └── ...
└── search_index.js           # (optional) Search index when search is enabled

Notes: - The first page is always index.html; additional pages go in html/ - Page filenames are derived from page titles (slugified, collision-safe) - Assets are stored under content/resources/ in the export; content.xml references them via {{context_path}}

content.xml Overview¶

content.xml uses the ODE (Open Digital Education) 2.0 format. It is a native XML document — not a Python object serialization — and can be validated against the bundled DTD.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE ode SYSTEM "content.dtd">
<ode xmlns="http://www.intef.es/xsd/ode" version="2.0">
  <userPreferences>...</userPreferences>
  <odeResources>...</odeResources>
  <odeProperties>...</odeProperties>
  <odeNavStructures>...</odeNavStructures>
</ode>

Key characteristics: - Namespace: http://www.intef.es/xsd/ode - Root element: <ode> with optional version attribute (currently "2.0") - HTML content is stored HTML-escaped inside <htmlView> and <jsonProperties> (no CDATA in the standard output; CDATA is used only when the content itself contains ]]>) - Page hierarchy is flat: parent-child relationships are expressed via <odeParentPageId>, not XML nesting

DTD / Formal Schema¶

The formal DTD is at:

public/app/schemas/ode/content.dtd

It is also bundled inside every .elpx file as content.dtd.

ID Format¶

All ODE identifiers (page IDs, block IDs, iDevice IDs, odeId, odeVersionId) use the format:

YYYYMMDDHHmmss + 6 random uppercase alphanumeric characters

Example: 20251125215855LURLBW

14-digit timestamp (YYYYMMDDHHMMSS)
6 characters from A-Z0-9

This gives a reasonably unique, time-sortable identifier that is safe to embed in XML and HTML.

Element Reference¶

`<ode>` — Root Element¶

<ode xmlns="http://www.intef.es/xsd/ode" version="2.0">
  ...
</ode>

Attribute	Required	Description
`xmlns`	Fixed	Always `http://www.intef.es/xsd/ode`
`version`	Optional	ODE format version; currently `"2.0"`

Contains (in order): userPreferences?, odeResources?, odeProperties?, odeNavStructures.

`<userPreferences>` / `<userPreference>`¶

Stores user-level configuration (currently only the active theme).

<userPreferences>
  <userPreference>
    <key>theme</key>
    <value>base</value>
  </userPreference>
</userPreferences>

Each <userPreference> has a <key> and <value> child. Currently only theme is used.

`<odeResources>` / `<odeResource>`¶

Package-level identifiers and version information.

<odeResources>
  <odeResource>
    <key>odeId</key>
    <value>20251125215855LURLBW</value>
  </odeResource>
  <odeResource>
    <key>odeVersionId</key>
    <value>20251125220103ABCXYZ</value>
  </odeResource>
  <odeResource>
    <key>eXeVersion</key>
    <value>v3.0.0</value>
  </odeResource>
</odeResources>

Key	Description
`odeId`	Stable project identifier (generated once on creation)
`odeVersionId`	Changes on every save (tracks the version)
`eXeVersion`	eXeLearning version that generated this file
`odeVersionName`	Human-readable version label (optional)
`isDownload`	`"true"` when project includes download-source-file iDevice

`<odeProperties>` / `<odeProperty>`¶

Document metadata. Each property is a <key>/<value> pair inside <odeProperty>.

<odeProperties>
  <odeProperty>
    <key>pp_title</key>
    <value>My Learning Content</value>
  </odeProperty>
  ...
</odeProperties>

Standard Property Keys¶

Key	Type	Description
`pp_title`	string	Project title
`pp_subtitle`	string	Project subtitle
`pp_author`	string	Author name
`pp_lang`	string	Language code (e.g., `"en"`, `"es"`)
`license`	string	License identifier (e.g., `"creative commons: attribution - share alike 4.0"`)
`pp_description`	string	Project description
`pp_addExeLink`	boolean	Include "Made with eXeLearning" footer link
`pp_addPagination`	boolean	Add page navigation
`pp_addSearchBox`	boolean	Include search box
`pp_addAccessibilityToolbar`	boolean	Include accessibility toolbar
`pp_addMathJax`	boolean	Load MathJax for LaTeX rendering
`exportSource`	boolean	Include editable source in export
`pp_extraHeadContent`	string (HTML)	Custom `<head>` HTML injected into all pages
`footer`	string (HTML)	Custom footer HTML
`pp_globalFont`	string	Global font override (e.g., `"default"`)
`pp_style`	string	Theme name (also stored in `userPreferences`)

Boolean values are stored as the strings "true" or "false".

`<odeNavStructures>` / `<odeNavStructure>`¶

Contains all pages of the project as a flat list. Parent-child relationships are expressed via <odeParentPageId>.

<odeNavStructures>
  <odeNavStructure>
    <odePageId>20251125215855PAGE01</odePageId>
    <odeParentPageId/>                          <!-- empty = root page -->
    <pageName>Introduction</pageName>
    <odeNavStructureOrder>1</odeNavStructureOrder>
    <odeNavStructureProperties>...</odeNavStructureProperties>
    <odePagStructures>...</odePagStructures>
  </odeNavStructure>
  <odeNavStructure>
    <odePageId>20251125215855PAGE02</odePageId>
    <odeParentPageId>20251125215855PAGE01</odeParentPageId>  <!-- child of PAGE01 -->
    <pageName>Section 1.1</pageName>
    <odeNavStructureOrder>1</odeNavStructureOrder>
    ...
  </odeNavStructure>
</odeNavStructures>

`<odeNavStructure>` child elements¶

Element	Description
`<odePageId>`	Unique page identifier
`<odeParentPageId>`	Parent page ID, empty for root-level pages
`<pageName>`	Page title (used in navigation)
`<odeNavStructureOrder>`	Numeric sort order among siblings
`<odeNavStructureProperties>`	Page-level properties (see below)
`<odePagStructures>`	Blocks contained in this page

Page Properties (`<odeNavStructureProperty>`)¶

Key	Type	Description
`titleNode`	string	Navigation label (may differ from `pageName`)
`titlePage`	string	Rendered page heading
`titleHtml`	string (HTML)	Custom HTML title override
`hidePageTitle`	boolean	Hide the page `<h1>` heading
`editableInPage`	boolean	Allow inline title editing
`visibility`	boolean	Whether the page is visible
`highlight`	boolean	Highlight this page in the navigation
`description`	string	Short description for the page

`<odePagStructures>` / `<odePagStructure>`¶

Blocks are containers inside a page. Each block can hold one or more iDevice components.

<odePagStructures>
  <odePagStructure>
    <odePageId>20251125215855PAGE01</odePageId>
    <odeBlockId>20251125215855BLK001</odeBlockId>
    <blockName>Text</blockName>
    <iconName/>
    <odePagStructureOrder>1</odePagStructureOrder>
    <odePagStructureProperties>...</odePagStructureProperties>
    <odeComponents>...</odeComponents>
  </odePagStructure>
</odePagStructures>

`<odePagStructure>` child elements¶

Element	Description
`<odePageId>`	ID of the containing page (redundant but required by DTD)
`<odeBlockId>`	Unique block identifier
`<blockName>`	Human-readable block label
`<iconName>`	Optional icon identifier
`<odePagStructureOrder>`	Sort order within the page
`<odePagStructureProperties>`	Block-level properties
`<odeComponents>`	iDevice components in this block

Block Properties (`<odePagStructureProperty>`)¶

Key	Type	Description
`visibility`	boolean	Whether the block is visible
`teacherOnly`	boolean	Restrict block to teacher view
`allowToggle`	boolean	Allow block to be collapsed
`minimized`	boolean	Block starts collapsed
`identifier`	string	Optional CSS `id` attribute
`cssClass`	string	Optional extra CSS class(es)

`<odeComponents>` / `<odeComponent>`¶

Each <odeComponent> is an iDevice (interactive learning element).

<odeComponents>
  <odeComponent>
    <odePageId>20251125215855PAGE01</odePageId>
    <odeBlockId>20251125215855BLK001</odeBlockId>
    <odeIdeviceId>20251125215855IDEV01</odeIdeviceId>
    <odeIdeviceTypeName>text</odeIdeviceTypeName>
    <htmlView>&lt;p&gt;Hello world&lt;/p&gt;</htmlView>
    <jsonProperties>{"textTextarea":"&lt;p&gt;Hello world&lt;/p&gt;"}</jsonProperties>
    <odeComponentsOrder>1</odeComponentsOrder>
    <odeComponentsProperties>...</odeComponentsProperties>
  </odeComponent>
</odeComponents>

`<odeComponent>` child elements¶

Element	Description
`<odePageId>`	ID of the containing page
`<odeBlockId>`	ID of the containing block
`<odeIdeviceId>`	Unique iDevice identifier
`<odeIdeviceTypeName>`	iDevice type string (see Common iDevice Types)
`<htmlView>`	Pre-rendered HTML (HTML-escaped)
`<jsonProperties>`	iDevice configuration JSON (HTML-escaped)
`<odeComponentsOrder>`	Sort order within the block
`<odeComponentsProperties>`	Component-level properties

Component Properties (`<odeComponentsProperty>`)¶

Key	Type	Description
`visibility`	boolean	Whether the iDevice is visible
`teacherOnly`	boolean	Restrict iDevice to teacher view
`identifier`	string	Optional CSS `id` attribute
`cssClass`	string	Optional extra CSS class(es)

Annotated Example¶

A minimal content.xml with one root page, one block, and one text iDevice:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE ode SYSTEM "content.dtd">
<ode xmlns="http://www.intef.es/xsd/ode" version="2.0">

  <!-- Theme selection -->
  <userPreferences>
    <userPreference>
      <key>theme</key>
      <value>base</value>
    </userPreference>
  </userPreferences>

  <!-- Project identifiers and version info -->
  <odeResources>
    <odeResource>
      <key>odeId</key>
      <value>20251125215855LURLBW</value>
    </odeResource>
    <odeResource>
      <key>odeVersionId</key>
      <value>20251125220103ABCXYZ</value>
    </odeResource>
    <odeResource>
      <key>eXeVersion</key>
      <value>v3.0.0</value>
    </odeResource>
  </odeResources>

  <!-- Document metadata -->
  <odeProperties>
    <odeProperty>
      <key>pp_title</key>
      <value>My Learning Content</value>
    </odeProperty>
    <odeProperty>
      <key>pp_author</key>
      <value>Jane Doe</value>
    </odeProperty>
    <odeProperty>
      <key>pp_lang</key>
      <value>en</value>
    </odeProperty>
    <odeProperty>
      <key>license</key>
      <value>creative commons: attribution - share alike 4.0</value>
    </odeProperty>
    <odeProperty>
      <key>pp_addExeLink</key>
      <value>true</value>
    </odeProperty>
    <odeProperty>
      <key>pp_addPagination</key>
      <value>false</value>
    </odeProperty>
  </odeProperties>

  <!-- Pages (flat list; parent-child via odeParentPageId) -->
  <odeNavStructures>

    <!-- Root page -->
    <odeNavStructure>
      <odePageId>20251125215855PAGE01</odePageId>
      <odeParentPageId/>       <!-- empty = root level -->
      <pageName>Introduction</pageName>
      <odeNavStructureOrder>1</odeNavStructureOrder>

      <odeNavStructureProperties>
        <odeNavStructureProperty>
          <key>titlePage</key>
          <value>Introduction</value>
        </odeNavStructureProperty>
        <odeNavStructureProperty>
          <key>visibility</key>
          <value>true</value>
        </odeNavStructureProperty>
        <odeNavStructureProperty>
          <key>hidePageTitle</key>
          <value>false</value>
        </odeNavStructureProperty>
      </odeNavStructureProperties>

      <!-- Blocks within the page -->
      <odePagStructures>
        <odePagStructure>
          <odePageId>20251125215855PAGE01</odePageId>
          <odeBlockId>20251125215855BLK001</odeBlockId>
          <blockName>Text</blockName>
          <iconName/>
          <odePagStructureOrder>1</odePagStructureOrder>

          <odePagStructureProperties>
            <odePagStructureProperty>
              <key>visibility</key>
              <value>true</value>
            </odePagStructureProperty>
            <odePagStructureProperty>
              <key>teacherOnly</key>
              <value>false</value>
            </odePagStructureProperty>
            <odePagStructureProperty>
              <key>allowToggle</key>
              <value>true</value>
            </odePagStructureProperty>
            <odePagStructureProperty>
              <key>minimized</key>
              <value>false</value>
            </odePagStructureProperty>
          </odePagStructureProperties>

          <!-- iDevice components within the block -->
          <odeComponents>
            <odeComponent>
              <odePageId>20251125215855PAGE01</odePageId>
              <odeBlockId>20251125215855BLK001</odeBlockId>
              <odeIdeviceId>20251125215855IDEV01</odeIdeviceId>
              <odeIdeviceTypeName>text</odeIdeviceTypeName>

              <!-- Pre-rendered HTML (HTML-escaped) -->
              <htmlView>&lt;div class="exe-text-template"&gt;&lt;p&gt;Hello world&lt;/p&gt;&lt;/div&gt;</htmlView>

              <!-- iDevice configuration JSON (HTML-escaped) -->
              <jsonProperties>{"textTextarea":"&lt;p&gt;Hello world&lt;/p&gt;"}</jsonProperties>

              <odeComponentsOrder>1</odeComponentsOrder>

              <odeComponentsProperties>
                <odeComponentsProperty>
                  <key>visibility</key>
                  <value>true</value>
                </odeComponentsProperty>
                <odeComponentsProperty>
                  <key>teacherOnly</key>
                  <value>false</value>
                </odeComponentsProperty>
              </odeComponentsProperties>
            </odeComponent>
          </odeComponents>

        </odePagStructure>
      </odePagStructures>
    </odeNavStructure>

    <!-- Child page (parent = PAGE01) -->
    <odeNavStructure>
      <odePageId>20251125215855PAGE02</odePageId>
      <odeParentPageId>20251125215855PAGE01</odeParentPageId>
      <pageName>Section 1.1</pageName>
      <odeNavStructureOrder>1</odeNavStructureOrder>
      <odeNavStructureProperties>
        <odeNavStructureProperty>
          <key>titlePage</key>
          <value>Section 1.1</value>
        </odeNavStructureProperty>
        <odeNavStructureProperty>
          <key>visibility</key>
          <value>true</value>
        </odeNavStructureProperty>
      </odeNavStructureProperties>
      <odePagStructures/>
    </odeNavStructure>

  </odeNavStructures>
</ode>

Asset References¶

Project assets (images, PDFs, audio, video) are stored in the ZIP under content/resources/. In content.xml, they are referenced using the {{context_path}} placeholder:

<img src="{{context_path}}/content/resources/photo.jpg" alt="Photo">

At export time, {{context_path}} is replaced by the relative path from the HTML page to the root of the ZIP. At import time, ElpxImporter converts these references back to internal asset:// URLs for use in the Yjs document.

Common iDevice Types¶

The <odeIdeviceTypeName> value identifies the iDevice type. Common type strings:

Type name	Description
`text`	Rich text / free text content
`form`	Data collection form
`matching`	Matching activity
`sort`	Ordering activity
`classify`	Classification activity
`guess`	Guess the word activity
`checklist`	Checklist activity
`crossword`	Crossword puzzle
`image-gallery`	Image gallery
`magnifier`	Image magnifier
`casestudy`	Case study
`external-website`	Embedded external website
`rubric`	Assessment rubric
`trueorfalse`	True or false questions
`quick-questions`	Quick quiz
`quick-questions-multiple-choice`	Multiple choice quiz
`complete`	Fill in the blanks
`download-source-file`	Download project source iDevice

Implementation Files¶

File	Role
`src/shared/export/exporters/ElpxExporter.ts`	Builds the ZIP archive (extends `Html5Exporter`)
`src/shared/export/generators/OdeXmlGenerator.ts`	Generates `content.xml` from `ExportMetadata` + pages
`src/shared/import/ElpxImporter.ts`	Parses `.elpx` and `.elp` files into a Yjs document
`public/app/schemas/ode/content.dtd`	Formal DTD for the ODE 2.0 format

Differences from Legacy .elp¶

For full documentation of the legacy format, see contentv3-format.md.

Aspect	`.elpx` (modern)	`.elp` (legacy)
Content file	`content.xml` (ODE 2.0)	`contentv3.xml` (Python pickle XML)
Root element	`<ode xmlns="...">`	`<instance class="exe.engine.package.Package">`
Serialization	Native XML	Python object serialization
Hierarchy	Flat list with `odeParentPageId`	Nested `Node` instances
Content storage	`<htmlView>`, `<jsonProperties>`	`<unicode content="true">`
Metadata	`<odeProperty>` elements	Dictionary key-value pairs
IDs	`YYYYMMDDHHmmss` + 6 chars	Sequential integers
DTD validation	Supported (`content.dtd`)	Not feasible (dynamic structure)
Asset paths	`{{context_path}}/content/resources/`	`resources/`
HTML output	Included in ZIP	Not included

ELPX Format Documentation (content.xml)¶

Overview¶

ZIP Structure¶

content.xml Overview¶

DTD / Formal Schema¶

ID Format¶

Element Reference¶

<ode> — Root Element¶

<userPreferences> / <userPreference>¶

<odeResources> / <odeResource>¶

<odeProperties> / <odeProperty>¶

Standard Property Keys¶

<odeNavStructures> / <odeNavStructure>¶

<odeNavStructure> child elements¶

Page Properties (<odeNavStructureProperty>)¶

<odePagStructures> / <odePagStructure>¶

<odePagStructure> child elements¶

Block Properties (<odePagStructureProperty>)¶

<odeComponents> / <odeComponent>¶

<odeComponent> child elements¶

Component Properties (<odeComponentsProperty>)¶