1 unstable release
0.6.0 | Aug 20, 2021 |
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#1787 in Encoding
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PHP serialization support for serde
Allows serialization and deserialization to/from PHP's serialize()
/unserialize()
format. See the documentation for details: docs.rs/php_serde.
lib.rs
:
PHP serialization format support for serde
PHP uses a custom serialization format through its
serialize()
and
unserialize()
methods. This crate adds partial support for this format using serde
.
An overview of the format can be seen at https://stackoverflow.com/questions/14297926/structure-of-a-serialized-php-string, details are available at http://www.phpinternalsbook.com/php5/classes_objects/serialization.html.
What is supported?
-
Basic and compound types:
PHP type Rust type boolean bool
integer i64
(automatic conversion to other types supported)float f64
(automatic conversion tof32
supported)strings Vec<u8>
(PHP strings are not UTF8)null decoded as None
array (non-associative) tuple struct
s orVec<_>
array (associative) regular struct
s orHashMap<_, _>
-
Rust
String
s are transparently UTF8-converted to PHP bytestrings.
Out-of-order arrays
PHP arrays can be created "out of order", as they store every array index as an explicit integer in the array. Thus the following code
$arr = array();
$arr[0] = "zero";
$arr[3] = "three";
$arr[2] = "two";
$arr[1] = "one";
results in an array that would be equivalent to ["zero", "one", "two", "three"], at least when iterated over.
Because deserialization does not buffer values, these arrays cannot be directly
serialized into a Vec
. Instead they should be deserialized into a map, which
can then be turned into a Vec
if desired.
A second concern are "holes" in the array, e.g. if the entry with key 1
is
missing. How to fill these is typically up to the user.
The helper function deserialize_unordered_array
can be used with serde's
deserialize_with
decorator to automatically buffer and order things, as well
as plugging holes by closing any gaps.
What is missing?
- PHP objects
- Non-string/numeric array keys, except when deserializing into a
HashMap
- Mixed arrays. Array keys are assumed to always have the same key type (Note: If this is required, consider extending this library with a variant type).
Example use
Given an example data structure storing a session token using the following PHP code
<?php
$serialized = serialize(array("user", "", array()));
echo($serialized);
and thus the following output
a:3:{i:0;s:4:"user";i:1;s:0:"";i:2;a:0:{}}
, the data can be reconstructed using the following rust code:
use serde::Deserialize;
use php_serde::from_bytes;
#[derive(Debug, Deserialize, Eq, PartialEq)]
struct Data(Vec<u8>, Vec<u8>, SubData);
#[derive(Debug, Deserialize, Eq, PartialEq)]
struct SubData();
let input = br#"a:3:{i:0;s:4:"user";i:1;s:0:"";i:2;a:0:{}}"#;
assert_eq!(
from_bytes::<Data>(input).unwrap(),
Data(b"user".to_vec(), b"".to_vec(), SubData())
);
Likewise, structs are supported as well, if the PHP arrays use keys:
<?php
$serialized = serialize(
array("foo" => true,
"bar" => "xyz",
"sub" => array("x" => 42))
);
echo($serialized);
In Rust:
#[derive(Debug, Deserialize, Eq, PartialEq)]
struct Outer {
foo: bool,
bar: String,
sub: Inner,
}
#[derive(Debug, Deserialize, Eq, PartialEq)]
struct Inner {
x: i64,
}
let input = br#"a:3:{s:3:"foo";b:1;s:3:"bar";s:3:"xyz";s:3:"sub";a:1:{s:1:"x";i:42;}}"#;
let expected = Outer {
foo: true,
bar: "xyz".to_owned(),
sub: Inner { x: 42 },
};
let deserialized: Outer = from_bytes(input).expect("deserialization failed");
assert_eq!(deserialized, expected);
Optional values
Missing values can be left optional, as in this example:
<?php
$location_a = array();
$location_b = array("province" => "Newfoundland and Labrador, CA");
$location_c = array("postalcode" => "90002",
"country" => "United States of America");
echo(serialize($location_a) . "\n");
echo(serialize($location_b) . "\n");
# -> a:1:{s:8:"province";s:29:"Newfoundland and Labrador, CA";}
echo(serialize($location_c) . "\n");
# -> a:2:{s:10:"postalcode";s:5:"90002";s:7:"country";
# s:24:"United States of America";}
The following declaration of Location
will be able to parse all three
example inputs.
#[derive(Debug, Deserialize, Eq, PartialEq)]
struct Location {
province: Option<String>,
postalcode: Option<String>,
country: Option<String>,
}
Full roundtrip example
use serde::{Deserialize, Serialize};
use php_serde::{to_vec, from_bytes};
#[derive(Debug, Deserialize, Eq, PartialEq, Serialize)]
struct UserProfile {
id: u32,
name: String,
tags: Vec<String>,
}
let orig = UserProfile {
id: 42,
name: "Bob".to_owned(),
tags: vec!["foo".to_owned(), "bar".to_owned()],
};
let serialized = to_vec(&orig).expect("serialization failed");
let expected = br#"a:3:{s:2:"id";i:42;s:4:"name";s:3:"Bob";s:4:"tags";a:2:{i:0;s:3:"foo";i:1;s:3:"bar";}}"#;
assert_eq!(serialized, &expected[..]);
let profile: UserProfile = from_bytes(&serialized).expect("deserialization failed");
assert_eq!(profile, orig);
Dependencies
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~10K SLoC