Jinja2

Describing Standard Filters

• Filters are operations that modify variables
• Filters are separated by a variable using the $\vert$ operator
• Multiple filters can be chained together
• The output of one filter is applied to the next
• For example, the {{ x|join(, ) }} uses a filter
• It joins a list $x$ with commas
• The tojson filter is useful for generating JavaScript on the fly:

<script type=text/javascript>
    doSomethingWith({{ user.username|tojson }});
</script>

Controlling Autoescaping

• Autoescaping refers to automatically escaping special characters

• Special characters in HTML refer to:

  • $\And$
  • $>$
  • $<$
  • $"$
  • $'$
• These characters carry specific meaning in documents
• Therefore, they need to be replaced by entities for displaying them as text

References

• Basics of Templates in Flask
• Details about Templating in Flask
• Filtering in Jinja2
• Defining Autoescaping in Templates