| … | |
… | |
| 1561 | constants. That means that the JSON true and false values will be |
1561 | constants. That means that the JSON true and false values will be |
| 1562 | comaptible to true and false values of iother modules that do the same, |
1562 | comaptible to true and false values of iother modules that do the same, |
| 1563 | such as L<JSON::PP> and L<CBOR::XS>. |
1563 | such as L<JSON::PP> and L<CBOR::XS>. |
| 1564 | |
1564 | |
| 1565 | |
1565 | |
|
|
1566 | =head1 INTEROPERABILITY WITH OTHER JSON DECODERS |
|
|
1567 | |
|
|
1568 | As long as you only serialise data that can be directly expressed in JSON, |
|
|
1569 | C<JSON::XS> is incapable of generating invalid JSON output (modulo bugs, |
|
|
1570 | but C<JSON::XS> has found more bugs in the official JSON testsuite (1) |
|
|
1571 | than the official JSON testsuite has found in C<JSON::XS> (0)). |
|
|
1572 | |
|
|
1573 | When you have trouble decoding JSON generated by this module using other |
|
|
1574 | decoders, then it is very likely that you have an encoding mismatch or the |
|
|
1575 | other decoder is broken. |
|
|
1576 | |
|
|
1577 | When decoding, C<JSON::XS> is strict by default and will likely catch all |
|
|
1578 | errors. There are currently two settings that change this: C<relaxed> |
|
|
1579 | makes C<JSON::XS> accept (but not generate) some non-standard extensions, |
|
|
1580 | and C<allow_tags> will allow you to encode and decode Perl objects, at the |
|
|
1581 | cost of not outputting valid JSON anymore. |
|
|
1582 | |
|
|
1583 | =head2 TAGGED VALUE SYNTAX AND STANDARD JSON EN/DECODERS |
|
|
1584 | |
|
|
1585 | When you use C<allow_tags> to use the extended (and also nonstandard and |
|
|
1586 | invalid) JSON syntax for serialised objects, and you still want to decode |
|
|
1587 | the generated When you want to serialise objects, you can run a regex |
|
|
1588 | to replace the tagged syntax by standard JSON arrays (it only works for |
|
|
1589 | "normal" packagesnames without comma, newlines or single colons). First, |
|
|
1590 | the readable Perl version: |
|
|
1591 | |
|
|
1592 | # if your FREEZE methods return no values, you need this replace first: |
|
|
1593 | $json =~ s/\( \s* (" (?: [^\\":,]+|\\.|::)* ") \s* \) \s* \[\s*\]/[$1]/gx; |
|
|
1594 | |
|
|
1595 | # this works for non-empty constructor arg lists: |
|
|
1596 | $json =~ s/\( \s* (" (?: [^\\":,]+|\\.|::)* ") \s* \) \s* \[/[$1,/gx; |
|
|
1597 | |
|
|
1598 | And here is a less readable version that is easy to adapt to other |
|
|
1599 | languages: |
|
|
1600 | |
|
|
1601 | $json =~ s/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/[$1,/g; |
|
|
1602 | |
|
|
1603 | Here is an ECMAScript version (same regex): |
|
|
1604 | |
|
|
1605 | json = json.replace (/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/g, "[$1,"); |
|
|
1606 | |
|
|
1607 | Since this syntax converts to standard JSON arrays, it might be hard to |
|
|
1608 | distinguish serialised objects from normal arrays. You can prepend a |
|
|
1609 | "magic number" as first array element to reduce chances of a collision: |
|
|
1610 | |
|
|
1611 | $json =~ s/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/["XU1peReLzT4ggEllLanBYq4G9VzliwKF",$1,/g; |
|
|
1612 | |
|
|
1613 | And after decoding the JSON text, you could walk the data |
|
|
1614 | structure looking for arrays with a first element of |
|
|
1615 | C<XU1peReLzT4ggEllLanBYq4G9VzliwKF>. |
|
|
1616 | |
|
|
1617 | The same approach cna be used to create the tagged format with another |
|
|
1618 | encoder. First, you create an array with the magic string as first member, |
|
|
1619 | the classname as second, and constructor arguments last, encode it as part |
|
|
1620 | of your JSON structure, and then: |
|
|
1621 | |
|
|
1622 | $json =~ s/\[\s*"XU1peReLzT4ggEllLanBYq4G9VzliwKF"\s*,\s*("([^\\":,]+|\\.|::)*")\s*,/($1)[/g; |
|
|
1623 | |
|
|
1624 | Again, this has some limitations - the magic string must not be encoded |
|
|
1625 | with character escapes, and the constructor arguments must be non-empty. |
|
|
1626 | |
| 1566 | =head1 THREADS |
1627 | =head1 THREADS |
| 1567 | |
1628 | |
| 1568 | This module is I<not> guaranteed to be thread safe and there are no |
1629 | This module is I<not> guaranteed to be thread safe and there are no |
| 1569 | plans to change this until Perl gets thread support (as opposed to the |
1630 | plans to change this until Perl gets thread support (as opposed to the |
| 1570 | horribly slow so-called "threads" which are simply slow and bloated |
1631 | horribly slow so-called "threads" which are simply slow and bloated |
