Input and Output Filters (Output Modifiers)

What are Filters?

Filters in Revolution allow you to manipulate the way data is presented or parsed in a tag. They allow you to modify values from inside your templates.

Input Filter

Currently the input filter processes tag calls in preparation for the output filter. It is generally used only internally by MODx.

Output Filter

In Revolution, the Output Filter applies one or more of series of output modifiers, which behave similarly to PHx calls in MODx Evolution - except they're built into the core. The syntax looks like this:

[[element:modifier=`value`]]

They can also be chained (executed left to right):

[[element:modifier:anothermodifier=`value`:andanothermodifier:yetanother=`value2`]]

You can also use these to modify Snippet output; note that the modifier comes after the Snippet name and before the question mark, e.g.

[[mySnippet:modifier=`value`? &mySnippetParam=`something`]]

Output Modifiers

The following table lists some of the existing modifiers and shows examples of their use. Although the examples below are placeholder tags, the output modifiers can be used with any MODx tag. Make sure that the placeholder used are actually receiving data.

Conditional output modifiers

String output modifiers

Caching

In general, any content in a placeholder that you think might change dynamically should be uncached. For example:

[[+placeholder:default=`A default value!`]]

This means that this could sometimes be empty, and sometimes not. Why would you ever want that cached? That would eliminate the point of the output modifier.

Sometimes, output modifiers can be used on a cached placeholder - but only if you're calling the Snippet that sets them cached as well. Otherwise, you're performing an illogical maneuver - trying to cache statically something that was never meant to be static.

In general, the rule is: If you set a placeholder in an uncached Snippet, the placeholder needs to be uncached as well if you expect the content of the placeholder to differ.

Using an Output Modifier with Tag Properties

If you have properties on the tag, you'll want to specify those after the modifier:

[[!getResources:default=`Sorry - nothing matched your search.`?
   &tplFirst=`blogTpl`
   &parents=`2,3,4,8`
   &tvFilters=`blog_tags==%[[!tag:htmlent]]%`
   &includeTVs=`1`]]

Creating a Custom Output Modifier

Also, Snippets can be used as custom modifiers. Simply put the Snippet name instead of the modifier. Example with a snippet named 'makeDownloadLink':

[[+file:makeDownloadLink=`notitle`]]

This will pass these properties to the snippet:

And then the return value of that call would be whatever the snippet returns. If the snippet returns an empty string, the output will not be modified at all.

Examples

A good example of chaining would be to format a date string to another format, like so:

[[+mydate:strtotime:date=`%Y-%m-%d`]]

Directly accessing the modx_user_attributes table in the database using output modifiers instead of a Snippet can be accomplished simply by utilizing the userinfo modifier. Select the appropriate column from the table and specify it as the property of the output modifier, like so:

User Internal Key: [[!+modx.user.id:userinfo=`internalKey`]]<br />
User name: [[!+modx.user.id:userinfo=`username`]]<br />
Full Name: [[!+modx.user.id:userinfo=`fullname`]]<br />
Role:  [[!+modx.user.id:userinfo=`role`]]<br />
E-mail: [[!+modx.user.id:userinfo=`email`]]<br />
Phone: [[!+modx.user.id:userinfo=`phone`]]<br />
Mobile Phone: [[!+modx.user.id:userinfo=`mobilephone`]]<br />
Fax: [[!+modx.user.id:userinfo=`fax`]]<br />
Date of birth: [[!+modx.user.id:userinfo=`dob`:date=`%Y-%m-%d`]]<br />
Gender: [[!+modx.user.id:userinfo=`gender`]]<br />
Country: [[+modx.user.id:userinfo=`country`]]<br />
State: [[+modx.user.id:userinfo=`state`]]<br />
Zip Code: [[+modx.user.id:userinfo=`zip`]]<br />
Photo: [[+modx.user.id:userinfo=`photo`]]<br />
Comment: [[+modx.user.id:userinfo=`comment`]]<br />
Password: [[+modx.user.id:userinfo=`password`]]<br />
Cache Password: [[+modx.user.id:userinfo=`cachepwd`]]<br />
Last Login: [[+modx.user.id:userinfo=`lastlogin`:date=`%Y-%m-%d`]]<br />
The Login:[[+modx.user.id:userinfo=`thislogin`:date=`%Y-%m-%d`]]<br />
Number of Logins: [[+modx.user.id:userinfo=`logincount`]]

[[!+modx.user.id]] defaults to the currently logged in user ID. You can of course replace that with [[*createdby]] or other resource field or placeholders that return a numeric ID representing a user.

Note that the user ID and username is already available by default in MODx, so you dont need to use the "userinfo" modifier: [[!+modx.user.id]] - Prints the ID [[!+modx.user.username]] - Prints the username You will most likely want to call these uncached (see note about caching above) to prevent unexpected results.

See Also

• Properties and Property Sets
• Templates
• Template Variables
• Snippets

Properties and Property Sets

Customizing Content