--- JSON-XS/XS.pm 2007/03/23 17:40:29 1.10 +++ JSON-XS/XS.pm 2007/03/24 02:23:51 1.16 @@ -6,6 +6,17 @@ use JSON::XS; + # exported functions, croak on error + + $utf8_encoded_json_text = to_json $perl_hash_or_arrayref; + $perl_hash_or_arrayref = from_json $utf8_encoded_json_text; + + # oo-interface + + $coder = JSON::XS->new->ascii->pretty->allow_nonref; + $pretty_printed_unencoded = $coder->encode ($perl_scalar); + $perl_scalar = $coder->decode ($unicode_json_text); + =head1 DESCRIPTION This module converts Perl data structures to JSON and vice versa. Its @@ -40,7 +51,7 @@ =item * strict checking of JSON correctness -There is no guessing, no generating of illegal JSON strings by default, +There is no guessing, no generating of illegal JSON texts by default, and only JSON is accepted as input by default (the latter is a security feature). @@ -69,7 +80,7 @@ package JSON::XS; BEGIN { - $VERSION = '0.3'; + $VERSION = '0.31'; @ISA = qw(Exporter); @EXPORT = qw(to_json from_json); @@ -86,21 +97,29 @@ =over 4 -=item $json_string = to_json $perl_scalar +=item $json_text = to_json $perl_scalar Converts the given Perl data structure (a simple scalar or a reference to a hash or array) to a UTF-8 encoded, binary string (that is, the string contains octets only). Croaks on error. -This function call is functionally identical to C<< JSON::XS->new->utf8->encode ($perl_scalar) >>. +This function call is functionally identical to: + + $json_text = JSON::XS->new->utf8->encode ($perl_scalar) + +except being faster. -=item $perl_scalar = from_json $json_string +=item $perl_scalar = from_json $json_text The opposite of C: expects an UTF-8 (binary) string and tries to -parse that as an UTF-8 encoded JSON string, returning the resulting simple +parse that as an UTF-8 encoded JSON text, returning the resulting simple scalar or reference. Croaks on error. -This function call is functionally identical to C<< JSON::XS->new->utf8->decode ($json_string) >>. +This function call is functionally identical to: + + $perl_scalar = JSON::XS->new->utf8->decode ($json_text) + +except being faster. =back @@ -119,42 +138,57 @@ The mutators for flags all return the JSON object again and thus calls can be chained: - my $json = JSON::XS->new->utf8(1)->space_after(1)->encode ({a => [1,2]}) + my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]}) => {"a": [1, 2]} =item $json = $json->ascii ([$enable]) -If C<$enable> is true (or missing), then the C method will -not generate characters outside the code range C<0..127>. Any unicode -characters outside that range will be escaped using either a single -\uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, as per -RFC4627. +If C<$enable> is true (or missing), then the C method will not +generate characters outside the code range C<0..127> (which is ASCII). Any +unicode characters outside that range will be escaped using either a +single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, +as per RFC4627. If C<$enable> is false, then the C method will not escape Unicode -characters unless necessary. +characters unless required by the JSON syntax. This results in a faster +and more compact format. - JSON::XS->new->ascii (1)->encode (chr 0x10401) - => \ud801\udc01 + JSON::XS->new->ascii (1)->encode ([chr 0x10401]) + => ["\ud801\udc01"] =item $json = $json->utf8 ([$enable]) If C<$enable> is true (or missing), then the C method will encode -the JSON string into UTF-8, as required by many protocols, while the +the JSON result into UTF-8, as required by many protocols, while the C method expects to be handled an UTF-8-encoded string. Please note that UTF-8-encoded strings do not contain any characters outside the -range C<0..255>, they are thus useful for bytewise/binary I/O. +range C<0..255>, they are thus useful for bytewise/binary I/O. In future +versions, enabling this option might enable autodetection of the UTF-16 +and UTF-32 encoding families, as described in RFC4627. If C<$enable> is false, then the C method will return the JSON string as a (non-encoded) unicode string, while C expects thus a unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs to be done yourself, e.g. using the Encode module. +Example, output UTF-16BE-encoded JSON: + + use Encode; + $jsontext = encode "UTF-16BE", JSON::XS->new->encode ($object); + +Example, decode UTF-32LE-encoded JSON: + + use Encode; + $object = JSON::XS->new->decode (decode "UTF-32LE", $jsontext); + =item $json = $json->pretty ([$enable]) This enables (or disables) all of the C, C and C (and in the future possibly more) flags in one call to generate the most readable (or most compact) form possible. +Example, pretty-print some simple structure: + my $json = JSON::XS->new->pretty(1)->encode ({a => [1,2]}) => { @@ -171,9 +205,9 @@ into its own line, identing them properly. If C<$enable> is false, no newlines or indenting will be produced, and the -resulting JSON strings is guarenteed not to contain any C. +resulting JSON text is guarenteed not to contain any C. -This setting has no effect when decoding JSON strings. +This setting has no effect when decoding JSON texts. =item $json = $json->space_before ([$enable]) @@ -183,8 +217,12 @@ If C<$enable> is false, then the C method will not add any extra space at those places. -This setting has no effect when decoding JSON strings. You will also most -likely combine this setting with C. +This setting has no effect when decoding JSON texts. You will also +most likely combine this setting with C. + +Example, space_before enabled, space_after and indent disabled: + + {"key" :"value"} =item $json = $json->space_after ([$enable]) @@ -196,7 +234,11 @@ If C<$enable> is false, then the C method will not add any extra space at those places. -This setting has no effect when decoding JSON strings. +This setting has no effect when decoding JSON texts. + +Example, space_before and indent disabled, space_after enabled: + + {"key": "value"} =item $json = $json->canonical ([$enable]) @@ -208,11 +250,11 @@ of the same script). This option is useful if you want the same data structure to be encoded as -the same JSON string (given the same overall settings). If it is disabled, +the same JSON text (given the same overall settings). If it is disabled, the same hash migh be encoded differently even if contains the same data, as key-value pairs have no inherent ordering in Perl. -This setting has no effect when decoding JSON strings. +This setting has no effect when decoding JSON texts. =item $json = $json->allow_nonref ([$enable]) @@ -222,16 +264,22 @@ values instead of croaking. If C<$enable> is false, then the C method will croak if it isn't -passed an arrayref or hashref, as JSON strings must either be an object +passed an arrayref or hashref, as JSON texts must either be an object or array. Likewise, C will croak if given something that is not a JSON object or array. +Example, encode a Perl scalar as JSON value with enabled C, +resulting in an invalid JSON text: + + JSON::XS->new->allow_nonref->encode ("Hello, World!") + => "Hello, World!" + =item $json = $json->shrink ([$enable]) Perl usually over-allocates memory a bit when allocating space for strings. This flag optionally resizes strings generated by either C or C to their minimum size possible. This can save -memory when your JSON strings are either very very long or you have many +memory when your JSON texts are either very very long or you have many short strings. It will also try to downgrade any strings to octet-form if possible: perl stores strings internally either in an encoding called UTF-X or in octet-form. The latter cannot store everything but uses less @@ -247,7 +295,7 @@ strings that look like integers or floats into integers or floats internally (there is no difference on the Perl level), saving space. -=item $json_string = $json->encode ($perl_scalar) +=item $json_text = $json->encode ($perl_scalar) Converts the given Perl data structure (a simple scalar or a reference to a hash or array) to its JSON representation. Simple scalars will be @@ -256,9 +304,9 @@ Perl values (e.g. C) become JSON C values. Neither C nor C values will be generated. -=item $perl_scalar = $json->decode ($json_string) +=item $perl_scalar = $json->decode ($json_text) -The opposite of C: expects a JSON string and tries to parse it, +The opposite of C: expects a JSON text and tries to parse it, returning the resulting simple scalar or reference. Croaks on error. JSON numbers and strings become simple Perl scalars. JSON arrays become @@ -285,7 +333,7 @@ =item object A JSON object becomes a reference to a hash in Perl. No ordering of object -keys is preserved. +keys is preserved (JSON does not preserver object key ordering itself). =item array @@ -331,7 +379,7 @@ Perl hash references become JSON objects. As there is no inherent ordering in hash keys, they will usually be encoded in a pseudo-random order that can change between runs of the same program but stays generally the same -within the single run of a program. JSON::XS can optionally sort the hash +within a single run of a program. JSON::XS can optionally sort the hash keys (determined by the I flag), so the same datastructure will serialise to the same JSON text (given same settings and version of JSON::XS), but this incurs a runtime overhead. @@ -381,6 +429,10 @@ You can not currently output JSON booleans or force the type in other, less obscure, ways. Tell me if you need this capability. +=item circular data structures + +Those will be encoded until memory or stackspace runs out. + =back =head1 COMPARISON @@ -417,7 +469,7 @@ values will make it croak). Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}> -which is not a valid JSON string. +which is not a valid JSON text. Unmaintained (maintainer unresponsive for many months, bugs are not getting fixed). @@ -429,7 +481,7 @@ Very inflexible (no human-readable format supported, format pretty much undocumented. I need at least a format for easy reading by humans and a single-line compact format for use in a protocol, and preferably a way to -generate ASCII-only JSON strings). +generate ASCII-only JSON texts). Completely broken (and confusingly documented) Unicode handling (unicode escapes are not working properly, you need to set ImplicitUnicode to @@ -462,7 +514,7 @@ No roundtripping. -Does not generate valid JSON (key strings are often unquoted, empty keys +Does not generate valid JSON texts (key strings are often unquoted, empty keys result in nothing being output) Does not check input for validity. @@ -476,10 +528,11 @@ in the JSON::XS distribution, to make it easy to compare on your own system. -First is a comparison between various modules using a very simple JSON -string, showing the number of encodes/decodes per second (JSON::XS is -the functional interface, while JSON::XS/2 is the OO interface with -pretty-printing and hashkey sorting enabled). +First comes a comparison between various modules using a very short JSON +string (83 bytes), showing the number of encodes/decodes per second +(JSON::XS is the functional interface, while JSON::XS/2 is the OO +interface with pretty-printing and hashkey sorting enabled). Higher is +better: module | encode | decode | -----------|------------|------------| @@ -494,7 +547,7 @@ That is, JSON::XS is 6 times faster than than JSON::DWIW and about 80 times faster than JSON, even with pretty-printing and key sorting. -Using a longer test string (roughly 8KB, generated from Yahoo! Locals +Using a longer test string (roughly 18KB, generated from Yahoo! Locals search API (http://nanoref.com/yahooapis/mgPdGg): module | encode | decode | @@ -510,8 +563,18 @@ Again, JSON::XS leads by far in the encoding case, while still beating every other module in the decoding case. -Last example is an almost 8MB large hash with many large binary values -(PNG files), resulting in a lot of escaping: +On large strings containing lots of unicode characters, some modules +(such as JSON::PC) decode faster than JSON::XS, but the result will be +broken due to missing unicode handling. Others refuse to decode or encode +properly, so it was impossible to prepare a fair comparison table for that +case. + +=head1 RESOURCE LIMITS + +JSON::XS does not impose any limits on the size of JSON texts or Perl +values they represent - if your machine can handle it, JSON::XS will +encode or decode it. Future versions might optionally impose structure +depth and memory use resource limits. =head1 BUGS