50 lines
2.2 KiB
Markdown
50 lines
2.2 KiB
Markdown
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---
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layout: default
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permalink: templates/escaping/
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title: Escaping
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---
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Escaping
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========
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Escaping is a form of [data filtering](http://www.phptherightway.com/#data_filtering) which sanitizes unsafe, user supplied input prior to outputting it as HTML. Plates provides two shortcuts to the `htmlspecialchars()` function.
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## Escaping example
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~~~ php
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<h1>Hello, <?=$this->escape($name)?></h1>
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<!-- Using the alternative, shorthand function -->
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<h1>Hello, <?=$this->e($name)?></h1>
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~~~
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## Batch function calls
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The escape functions also support [batch](/templates/functions/#batch-function-calls) function calls, which allow you to apply multiple functions, including native PHP functions, to a variable at one time.
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~~~ php
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<p>Welcome <?=$this->e($name, 'strip_tags|strtoupper')?></p>
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~~~
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## Escaping HTML attributes
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<p class="message-notice">It's VERY important to always double quote HTML attributes that contain escaped variables, otherwise your template will still be open to injection attacks.</p>
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Some [libraries](http://framework.zend.com/manual/2.1/en/modules/zend.escaper.escaping-html-attributes.html) go as far as having a special function for escaping HTML attributes. However, this is somewhat redundant considering that if a developer forgets to properly quote an HTML attribute, they will likely also forget to use this special function. Here is how you properly escape HTML attributes:
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~~~ php
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<!-- Good -->
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<img src="portrait.jpg" alt="<?=$this->e($name)?>">
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<!-- BAD -->
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<img src="portrait.jpg" alt='<?=$this->e($name)?>'>
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<!-- BAD -->
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<img src="portrait.jpg" alt=<?=$this->e($name)?>>
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~~~
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## Automatic escaping
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Probably the biggest drawbacks to native PHP templates is the inability to auto-escape variables properly. Template languages like Twig and Smarty can identify "echoed" variables during a parsing stage and automatically escape them. This cannot be done in native PHP as the language does not offer overloading functionality for it's output functions (ie. `print` and `echo`).
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Don't worry, escaping can still be done safely, it just means you are responsible for manually escaping each variable on output. Consider creating a snippet for one of the above, built-in escaping functions to make this process easier.
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