alfresco-content-app/docs/extending/rules.md

Title

Title
Rules

Rules

Rules allow you to evaluate conditions for extension components, so you can disable or hide elements based on certain rules, for example.

Every rule is backed by a condition evaluator.

{
  "$schema": "../../../extension.schema.json",
  "$version": "1.0.0",
  "$name": "plugin1",

  "rules": [
    {
      "id": "app.trashcan",
      "type": "app.navigation.isTrashcan"
    }
  ]
}

Rules can accept other rules as parameters:

{
  "$schema": "../../../extension.schema.json",
  "$version": "1.0.0",
  "$name": "plugin1",

  "rules": [
    {
      "id": "app.toolbar.favorite.canAdd",
      "type": "core.every",
      "parameters": [
        { "type": "rule", "value": "app.selection.canAddFavorite" },
        { "type": "rule", "value": "app.navigation.isNotRecentFiles" },
        { "type": "rule", "value": "app.navigation.isNotSharedFiles" },
        { "type": "rule", "value": "app.navigation.isNotSearchResults" }
      ]
    }
  ]
}

Tip: You can also negate any rule by utilizing a ! prefix: !app.navigation.isTrashcan is the opposite of the app.navigation.isTrashcan.

It is also possible to use inline references to registered evaluators without declaring rules, in case you do not need providing extra parameters, or chaining multiple rules together.

{
  "$schema": "../../../extension.schema.json",
  "$version": "1.0.0",
  "$name": "plugin1",

  "features": {
    "toolbar": [
      {
        "id": "app.toolbar.share",
        "rules": {
          "visible": "app.record.canShareRecord"
        }
      }
    ]
  } 
}

Handling Multiple Extensions

When multiple extensions rely on the same component, the visibility rules from all extensions should be passed as an array. This way, the rules will be merged and evaluated, ensuring that all conditions from different extensions are considered.

For example, if the app.toolbar.share component is modified by both the Extension1 and Extension2 extensions, the visibility rules will be combined:

{
  "$schema": "../../../extension.schema.json",
  "$version": "1.0.0",
  "$name": "Extension1",

  "features": {
    "toolbar": [
      {
        "id": "app.toolbar.share",
        "rules": {
          "visible": ["extension1.rule1"]
        }
      }
    ]
  } 
}

{
  "$schema": "../../../extension.schema.json",
  "$version": "1.0.0",
  "$name": "Extension2",

  "features": {
    "toolbar": [
      {
        "id": "app.toolbar.share",
        "rules": {
          "visible": ["extension2.rule2"]
        }
      }
    ]
  } 
}

In this case, the component will be visible only if both extension1.rule1 and extension2.rule2 evaluate to true.

Core Evaluators

You can create new rules by chaining other rules and evaluators.

Version	Key	Description
1.7.0	core.every	Evaluates to true if all chained rules evaluate to true.
1.7.0	core.some	Evaluates to true if at least one of the chained rules evaluates to true.
1.7.0	core.not	Evaluates to true if all chained rules evaluate to false.

Below is an example of the composite rule definition that combines the following conditions:

• user has selected a single file
• user is not using the Trashcan page

{
  "$schema": "../../../extension.schema.json",
  "$version": "1.0.0",
  "$name": "plugin1",

  "rules": [
    {
      "id": "app.toolbar.canViewFile",
      "type": "core.every",
      "parameters": [
        {
          "type": "rule",
          "value": "app.selection.file"
        },
        {
          "type": "rule",
          "value": "core.not",
          "parameters": [
            {
              "type": "rule",
              "value": "app.navigation.isTrashcan"
            }
          ]
        }
      ]
    }
  ]
}

You can now declare a toolbar button action that is based on the rule above.

{
  "$schema": "../../../extension.schema.json",
  "$version": "1.0.0",
  "$name": "plugin1",

  "features": {
    "toolbar": [
      {
        "id": "app.toolbar.preview",
        "type": "button",
        "title": "View File",
        "icon": "open_in_browser",
        "actions": {
          "click": "VIEW_FILE"
        },
        "rules": {
          "visible": "app.toolbar.canViewFile"
        }
      }
    ]
  }
}

The button will be visible only when the linked rule evaluates to true.

Tips:

1. You can also negate any rule by utilizing a ! prefix: !app.navigation.isTrashcan is the opposite of the app.navigation.isTrashcan.
2. See the Registration section for more details on how to register your own entries to be re-used at runtime.
3. See Rules List for a full list of rules available with the Alfresco Content Application

Example

The rule in the example below evaluates to true if all the conditions are met:

• user has selected node(s)
• user is not using the Trashcan page
• user is not using a Libraries page (My Libraries, Favorite Libraries or Libraries Search Results pages)

{
  "$schema": "../../../extension.schema.json",
  "$version": "1.0.0",
  "$name": "plugin1",

  "rules": [
    {
      "id": "app.toolbar.canCopyNode",
      "type": "core.every",
      "parameters": [
        { "type": "rule", "value": "app.selection.notEmpty" },
        { "type": "rule", "value": "app.navigation.isNotTrashcan" },
        { "type": "rule", "value": "app.navigation.isNotLibraries" }
      ]
    }
  ]
}