Jinja is a
web template engine for the
Python programming language. It was created by
Armin Ronacher and is licensed under a
BSD License. Jinja is similar to the
Django template engine, but provides Python-like expressions while ensuring that the templates are evaluated in a
sandbox
A sandbox is a sandpit, a wide, shallow playground construction to hold sand, often made of wood or plastic.
Sandbox or sand box may also refer to:
Arts, entertainment, and media
* Sandbox (band), a Canadian rock music group
* Sandbox (Gu ...
. It is a text-based template language and thus can be used to generate any markup as well as source code.
The Jinja template engine allows customization of
tags,
(for formatting or transforming values
),
tests (for evaluating conditions
), and
globals.
Also, unlike the Django template engine, Jinja allows the template designer to call functions with arguments on objects.
Jinja is
Flask's default template engine
and it is also used by
Ansible,
Trac, and
Salt
In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...
. It is also used to make SQL
macros, for example for use with
dbt.
Features
Some of the features of Jinja are:
* sandboxed execution
* automatic
HTML escaping to prevent
cross-site scripting (XSS) attacks
* template inheritance
* compiles down to the optimal Python code just-in-time
* optional ahead-of-time template compilation
* easy to debug (for example, line numbers of exceptions directly point to the correct line in the template)
* configurable syntax
Jinja, like
Smarty, also ships with an easy-to-use filter system similar to the
Unix
Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...
pipeline
A pipeline is a system of Pipe (fluid conveyance), pipes for long-distance transportation of a liquid or gas, typically to a market area for consumption. The latest data from 2014 gives a total of slightly less than of pipeline in 120 countries ...
.
Syntax
The syntax for printing output in Jinja is using the double curly braces, for example
.
Statements which set variables in jinja or those which do not have an output can be wrapped within
, using the
set keyword. For example
sets a variable called
foo with a value of 42.
Similar to above, comments in jinja can be written using a number sign (
#) instead of a percentage (
%), for example,
.
The syntax for creating a filter in Jinja is a
vertical bar
The vertical bar, , is a glyph with various uses in mathematics, computing, and typography. It has many names, often related to particular meanings: Sheffer stroke (in logic), pipe, bar, or (literally, the word "or"), vbar, and others.
Usage
...
(
, ), for example
. A variable can have multiple filters, for example
).
The syntax for creating a test in Jinja is the keyword
is as well as the conditions for evaluating the validity of a test, such as for example
do something).
can be used to iterate over sequences, while retaining their object properties. The following example demonstrates iterating over a list of users with and fields.
Although and are not allowed inside loops, sequences can be filtered.
Example
Here is a small example of a template file
example.html.jinja:
,
and templating code:
from jinja2 import Template
with open("example.html.jinja") as f:
tmpl = Template(f.read())
print(tmpl.render(
variable = "Value with data",
item_list = , 2, 3, 4, 5, 6))
This produces the HTML string:
Value with <unsafe> data
1,
2,
3,
4,
5,
6
Note the
minus sign
The plus sign () and the minus sign () are mathematical symbols used to denote positive and negative functions, respectively. In addition, the symbol represents the operation of addition, which results in a sum, while the symbol represent ...
(
-) after the tag
{%: If you add a minus sign (
-) to the start or end of a block (e.g. a For tag), a comment, or a variable expression, the whitespaces before or after that block will be removed.
References
External links
* {{Official website, https://palletsprojects.com/p/jinja/
Free software programmed in Python
Free system software
Python (programming language) libraries
Python (programming language) software
Template engines
Software using the BSD license
Articles with example Python (programming language) code