mirror of
https://github.com/OpenXE-org/OpenXE.git
synced 2024-12-26 22:50:29 +01:00
124 lines
3.9 KiB
ReStructuredText
124 lines
3.9 KiB
ReStructuredText
============
|
|
jmespath.php
|
|
============
|
|
|
|
JMESPath (pronounced "jaymz path") allows you to declaratively specify how to
|
|
extract elements from a JSON document. *jmespath.php* allows you to use
|
|
JMESPath in PHP applications with PHP data structures. It requires PHP 5.4 or
|
|
greater and can be installed through `Composer <http://getcomposer.org/doc/00-intro.md>`_
|
|
using the ``mtdowling/jmespath.php`` package.
|
|
|
|
.. code-block:: php
|
|
|
|
require 'vendor/autoload.php';
|
|
|
|
$expression = 'foo.*.baz';
|
|
|
|
$data = [
|
|
'foo' => [
|
|
'bar' => ['baz' => 1],
|
|
'bam' => ['baz' => 2],
|
|
'boo' => ['baz' => 3]
|
|
]
|
|
];
|
|
|
|
JmesPath\search($expression, $data);
|
|
// Returns: [1, 2, 3]
|
|
|
|
- `JMESPath Tutorial <http://jmespath.org/tutorial.html>`_
|
|
- `JMESPath Grammar <http://jmespath.org/specification.html#grammar>`_
|
|
- `JMESPath Python library <https://github.com/jmespath/jmespath.py>`_
|
|
|
|
PHP Usage
|
|
=========
|
|
|
|
The ``JmesPath\search`` function can be used in most cases when using the
|
|
library. This function utilizes a JMESPath runtime based on your environment.
|
|
The runtime utilized can be configured using environment variables and may at
|
|
some point in the future automatically utilize a C extension if available.
|
|
|
|
.. code-block:: php
|
|
|
|
$result = JmesPath\search($expression, $data);
|
|
|
|
// or, if you require PSR-4 compliance.
|
|
$result = JmesPath\Env::search($expression, $data);
|
|
|
|
Runtimes
|
|
--------
|
|
|
|
jmespath.php utilizes *runtimes*. There are currently two runtimes:
|
|
AstRuntime and CompilerRuntime.
|
|
|
|
AstRuntime is utilized by ``JmesPath\search()`` and ``JmesPath\Env::search()``
|
|
by default.
|
|
|
|
AstRuntime
|
|
~~~~~~~~~~
|
|
|
|
The AstRuntime will parse an expression, cache the resulting AST in memory,
|
|
and interpret the AST using an external tree visitor. AstRuntime provides a
|
|
good general approach for interpreting JMESPath expressions that have a low to
|
|
moderate level of reuse.
|
|
|
|
.. code-block:: php
|
|
|
|
$runtime = new JmesPath\AstRuntime();
|
|
$runtime('foo.bar', ['foo' => ['bar' => 'baz']]);
|
|
// > 'baz'
|
|
|
|
CompilerRuntime
|
|
~~~~~~~~~~~~~~~
|
|
|
|
``JmesPath\CompilerRuntime`` provides the most performance for
|
|
applications that have a moderate to high level of reuse of JMESPath
|
|
expressions. The CompilerRuntime will walk a JMESPath AST and emit PHP source
|
|
code, resulting in anywhere from 7x to 60x speed improvements.
|
|
|
|
Compiling JMESPath expressions to source code is a slower process than just
|
|
walking and interpreting a JMESPath AST (via the AstRuntime). However,
|
|
running the compiled JMESPath code results in much better performance than
|
|
walking an AST. This essentially means that there is a warm-up period when
|
|
using the ``CompilerRuntime``, but after the warm-up period, it will provide
|
|
much better performance.
|
|
|
|
Use the CompilerRuntime if you know that you will be executing JMESPath
|
|
expressions more than once or if you can pre-compile JMESPath expressions
|
|
before executing them (for example, server-side applications).
|
|
|
|
.. code-block:: php
|
|
|
|
// Note: The cache directory argument is optional.
|
|
$runtime = new JmesPath\CompilerRuntime('/path/to/compile/folder');
|
|
$runtime('foo.bar', ['foo' => ['bar' => 'baz']]);
|
|
// > 'baz'
|
|
|
|
Environment Variables
|
|
^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
You can utilize the CompilerRuntime in ``JmesPath\search()`` by setting
|
|
the ``JP_PHP_COMPILE`` environment variable to "on" or to a directory
|
|
on disk used to store cached expressions.
|
|
|
|
Testing
|
|
=======
|
|
|
|
A comprehensive list of test cases can be found at
|
|
https://github.com/jmespath/jmespath.php/tree/master/tests/compliance.
|
|
These compliance tests are utilized by jmespath.php to ensure consistency with
|
|
other implementations, and can serve as examples of the language.
|
|
|
|
jmespath.php is tested using PHPUnit. In order to run the tests, you need to
|
|
first install the dependencies using Composer as described in the *Installation*
|
|
section. Next you just need to run the tests via make:
|
|
|
|
.. code-block:: bash
|
|
|
|
make test
|
|
|
|
You can run a suite of performance tests as well:
|
|
|
|
.. code-block:: bash
|
|
|
|
make perf
|