I've been looking for a MongoDb-like ( http://docs.mongodb.org/manual/applications/read/#find, docs.mongodb.org/manual/reference/operators/ ) query expression object evaluation function implementation or a class. It may cover not all the advanced features, and should have extensible architecture.
MongoDB-like query expression objects are easy for understanding and usage, providing ability to write clean, self-explaining code, because both query and objects to search in, are associative arrays.
Basically talking its a convenient function to extract information from php arrays. Knowing the array structure(the arrayPath), it will allow to perform operations on multidimensional arrays data, without the need for multiple nested loops.
If you are not familiar with MongoDb, take a look at a given expression object and array to search in.
I wrote it as JSON string for simplicity. The object contents makes no sense, just showng the MongoDb query syntax.
MongoDb-like query expression object
{
"name": "Mongo",
"type": "db",
"arch": {
"$in": [
"x86",
"x64"
]
},
"version": {
"$gte": 22
},
"released": {
"$or": {
"$lt": 2013,
"$gt": 2012
}
}
}
The array to search in
[
{
"name": "Mongo",
"type": "db",
"release": {
"arch": "x86",
"version": 22,
"year": 2012
}
},
{
"name": "Mongo",
"type": "db",
"release": {
"arch": "x64",
"version": 21,
"year": 2012
}
},
{
"name": "Mongo",
"type": "db",
"release": {
"arch": "x86",
"version": 23,
"year": 2013
}
}
]
Find using Mongo-like query expressions
So, with the help of the function, we should be able to issue the following query to the target array.
$found=findLikeMongo($array, $queryExpr); //resulting in a $array[0] value;
//@return found array
Get array path using Mongo-like query expressions
$arrayPath=getPathFromMongo($array, $queryExpr);// resulting in array("0")
//@return array path, represented as an array where entries are consecutive keys.
Homework
I found that goessner.net/articles/JsonPath/ could possibly cover my needs(not being an exact match because it uses Xpath-like expressions), the caveat is, that it heavily relies on regular expressions and string parsing, what will definitely slow it down compared to array only(JSON like) implementation.
Also I've found a similar question here, @stackoverflow Evaluating MongoDB-like JSON Queries in PHP. The resulting answer was to use some SPL functions, which I am used to avoid most of the time.
Wonder if the author had came up with function, he had been trying to develop.The possible arrayPath implementation was found on thereisamoduleforthat.com/content/dealing-deep-arrays-php, thus the lack of this implementation, is that it relies on pointers.
I know its not a trivial question with a oneliner answer, that's why I'm asking it before starting the actual development of my own class.
I appreciate architecture tips, related or similar code, which may be a good practice example for building php "if..else" expressions on the fly.emphasized text
How to write a non-SPL version?
@Baba provided an excellent class, which is written with the use of SPL. I wonder how to rewrite this code without SPL.
There are two reasons for this
- calling the class multiple times will give function overhead, that can be avoided rewriting it in raw PHP.
- it would be easily portable to raw Javascript where SPL is not available, leading to easier code maintenance on both platforms.
Results
The created ArrayQuery class is published on Github, consider checking-out the repository for updates.
SPL, raw PHP version and Chequer2 FORP profiler output
In brief-
- the raw PHP version performs 10x faster than the SPL one, consuming 20% less memory.
- Chequer2 class performs 40% slower than PHP SPL class, and almost 20x slower than raw PHP version.
- MongoDb is the fastest(10x faster than raw PHP implementation and consumes 5x less memory), do not use these classes unless you are sure you want to avoid interaction with MongoDb.
MongoDb version
SPL version
Raw PHP(latest ArrayQuery class) version
Chequer2 version
MongoDb reference test profiling code
$m = new MongoClient(); // connect
$db = $m->testmongo; // select a database
$collection = $db->data;
$loops=100;
for ($i=0; $i<$loops; $i++) {
$d = $collection->find(array("release.year" => 2013));
}
print_r( iterator_to_array($d) );
PHP with SPL class profiling code
include('data.php');
include('phpmongo-spl.php');
$s = new ArrayCollection($array, array("release.year" => 2013),false);
$loops=100;
for ($i=0; $i<$loops; $i++) {
$d = $s->parse();
}
print_r( $d );
The SPL class parse() function has been slightly modified to return the value after execution, it could be also be modified to accept expression, but it's not essential for profiling purposes as the expression is being reevaluated every time.
raw PHP(latest ArrayQuery class) profiling code
include('data.php');
include('phpmongo-raw.php');
$s = new ArrayStandard($array);
$loops=100;
for ($i=0; $i<$loops; $i++) {
$d = $s->find(array("release.year" => 2013));
}
print_r( $d );
chequer2 PHP profiling code
<?php
include('data.php');
include('../chequer2/Chequer.php');
$query=array("release.year" => 2013);
$loops=100;
for ($i=0; $i<$loops; $i++) {
$result=Chequer::shorthand('(.release.year > 2012) ? (.) : NULL')
->walk($array);
}
print_r($result);
?>
data used(same as @baba provided in his answer)
$json = '[{
"name":"Mongo",
"type":"db",
"release":{
"arch":"x86",
"version":22,
"year":2012
}
},
{
"name":"Mongo",
"type":"db",
"release":{
"arch":"x64",
"version":21,
"year":2012
}
},
{
"name":"Mongo",
"type":"db",
"release":{
"arch":"x86",
"version":23,
"year":2013
}
},
{
"key":"Diffrent",
"value":"cool",
"children":{
"tech":"json",
"lang":"php",
"year":2013
}
}
]';
$array = json_decode($json, true);
the forp-ui slightly modified sample ui loader(to be called with ?profile=FILE_TO_PROFILE)
<!doctype html>
<html>
<head>
<style>
body {margin : 0px}
</style>
</head>
<body>
<div class="forp"></div>
<?php
register_shutdown_function(
function() {
// next code can be append to PHP scripts in dev mode
?>
<script src="../forp-ui/js/forp.min.js"></script>
<script>
(function(f) {
f.find(".forp")
.each(
function(el) {
el.css('margin:50px;height:300px;border:1px solid #333');
}
)
.forp({
stack : <?php echo json_encode(forp_dump()); ?>,
//mode : "fixed"
})
})(forp);
</script>
<?php
}
);
// start forp
forp_start();
// our PHP script to profile
include($_GET['profile']);
// stop forp
forp_end();
?>
</body>
</html>