| commit | author | age | ||
| 2207d6 | 1 | JSONPath |
| W | 2 | ============= |
| 3 | ||
| 4 | This is a [JSONPath](http://goessner.net/articles/JsonPath/) implementation for PHP based on Stefan Goessner's JSONPath script. | |
| 5 | ||
| 6 | JSONPath is an XPath-like expression language for filtering, flattening and extracting data. | |
| 7 | ||
| 8 | I believe that is improves on the original script (which was last updated in 2007) by doing a few things: | |
| 9 | ||
| 10 | - Object-oriented code (should be easier to manage or extend in future) | |
| 11 | - Expressions are parsed into tokens using some code cribbed from Doctrine Lexer and cached | |
| 12 | - There is no `eval()` in use | |
| 13 | - Performance is pretty much the same | |
| 14 | - Any combination of objects/arrays/ArrayAccess-objects can be used as the data input which is great if you're de-serializing JSON in to objects | |
| 15 | or if you want to process your own data structures. | |
| 16 | ||
| 17 | JSONPath Examples | |
| 18 | --- | |
| 19 | ||
| 20 | JSONPath | Result | |
| 21 | --------------------------|------------------------------------- | |
| 22 | `$.store.books[\*].author` | the authors of all books in the store | |
| 23 | `$..author` | all authors | |
| 24 | `$.store..price` | the price of everything in the store. | |
| 25 | `$..books[2]` | the third book | |
| 26 | `$..books[(@.length-1)]` | the last book in order. | |
| 27 | `$..books[0,1]` | the first two books | |
| 28 | `$..books[:2]` | the first two books | |
| 29 | `$..books[?(@.isbn)]` | filter all books with isbn number | |
| 30 | `$..books[?(@.price<10)]` | filter all books cheapier than 10 | |
| 31 | `$..*` | all elements in the data (recursively extracted) | |
| 32 | ||
| 33 | ||
| 34 | Expression syntax | |
| 35 | --- | |
| 36 | ||
| 37 | Symbol | Description | |
| 38 | ----------------------|------------------------- | |
| 39 | `$` | The root object/element (not strictly necessary) | |
| 40 | `@` | The current object/element | |
| 41 | `.` or `[]` | Child operator | |
| 42 | `..` | Recursive descent | |
| 43 | `*` | Wildcard. All child elements regardless their index. | |
| 44 | `[,]` | Array indices as a set | |
| 45 | `[start:end:step]` | Array slice operator borrowed from ES4/Python. | |
| 46 | `?()` | Filters a result set by a script expression | |
| 47 | `()` | Uses the result of a script expression as the index | |
| 48 | ||
| 49 | PHP Usage | |
| 50 | --- | |
| 51 | ||
| 52 | ```php | |
| 53 | $data = ['people' => [['name' => 'Joe'], ['name' => 'Jane'], ['name' => 'John']]]; | |
| 54 | $result = (new JSONPath($data))->find('$.people.*.name'); // returns new JSONPath | |
| 55 | // $result[0] === 'Joe' | |
| 56 | // $result[1] === 'Jane' | |
| 57 | // $result[2] === 'John' | |
| 58 | ``` | |
| 59 | ||
| 60 | ### Magic method access | |
| 61 | ||
| 62 | The options flag `JSONPath::ALLOW_MAGIC` will instruct JSONPath when retrieving a value to first check if an object | |
| 63 | has a magic `__get()` method and will call this method if available. This feature is *iffy* and | |
| 64 | not very predictable as: | |
| 65 | ||
| 66 | - wildcard and recursive features will only look at public properties and can't smell which properties are magically accessible | |
| 67 | - there is no `property_exists` check for magic methods so an object with a magic `__get()` will always return `true` when checking | |
| 68 | if the property exists | |
| 69 | - any errors thrown or unpredictable behaviour caused by fetching via `__get()` is your own problem to deal with | |
| 70 | ||
| 71 | ```php | |
| 72 | $jsonPath = new JSONPath($myObject, JSONPath::ALLOW_MAGIC); | |
| 73 | ``` | |
| 74 | ||
| 75 | For more examples, check the JSONPathTest.php tests file. | |
| 76 | ||
| 77 | Script expressions | |
| 78 | ------- | |
| 79 | ||
| 80 | Script expressions are not supported as the original author intended because: | |
| 81 | ||
| 82 | - This would only be achievable through `eval` (boo). | |
| 83 | - Using the script engine from different languages defeats the purpose of having a single expression evaluate the same way in different | |
| 84 | languages which seems like a bit of a flaw if you're creating an abstract expression syntax. | |
| 85 | ||
| 86 | So here are the types of query expressions that are supported: | |
| 87 | ||
| 88 | [?(@._KEY_ _OPERATOR_ _VALUE_)] // <, >, !=, and == | |
| 89 | Eg. | |
| 90 | [?(@.title == "A string")] // | |
| 91 | [?(@.title = "A string")] | |
| 92 | // A single equals is not an assignment but the SQL-style of '==' | |
| 93 | ||
| 94 | Similar projects | |
| 95 | ---------------- | |
| 96 | ||
| 97 | [JMESPath](https://github.com/jmespath) does similiar things, is full of features and has a PHP implementation | |
| 98 | ||
| 99 | The [Hash](http://book.cakephp.org/2.0/en/core-utility-libraries/hash.html) utility from CakePHP does some similar things | |
| 100 | ||
| 101 | The original JsonPath implementations is available at [http://code.google.com/p/jsonpath]() and re-hosted for composer | |
| 102 | here [Peekmo/JsonPath](https://github.com/Peekmo/JsonPath). | |
| 103 | ||
| 104 | [ObjectPath](http://objectpath.org) ([https://github.com/adriank/ObjectPath]()) appears to be a Python/JS implementation | |
| 105 | with a new name and extra features. | |
| 106 | ||
| 107 | Changelog | |
| 108 | --------- | |
| 109 | ||
| 110 | ### 0.3.0 | |
| 111 | - Added JSONPathToken class as value object | |
| 112 | - Lexer clean up and refactor | |
| 113 | - Updated the lexing and filtering of the recursive token ("..") to allow for a combination of recursion | |
| 114 | and filters, eg. $..[?(@.type == 'suburb')].name | |
| 115 | ||
| 116 | ### 0.2.1 - 0.2.5 | |
| 117 | - Various bug fixes and clean up | |
| 118 | ||
| 119 | ### 0.2.0 | |
| 120 | - Added a heap of array access features for more creative iterating and chaining possibilities | |
| 121 | ||
| 122 | ### 0.1.x | |
| 123 | - Init | |
