| … | |
… | |
| 157 | If no argument is given, the limit check will be deactivated (same as when |
157 | If no argument is given, the limit check will be deactivated (same as when |
| 158 | C<0> is specified). |
158 | C<0> is specified). |
| 159 | |
159 | |
| 160 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
160 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
| 161 | |
161 | |
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162 | =item $cbor = $cbor->allow_unknown ([$enable]) |
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163 | |
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164 | =item $enabled = $cbor->get_allow_unknown |
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165 | |
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166 | If C<$enable> is true (or missing), then C<encode> will I<not> throw an |
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167 | exception when it encounters values it cannot represent in CBOR (for |
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168 | example, filehandles) but instead will encode a CBOR C<error> value. |
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169 | |
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170 | If C<$enable> is false (the default), then C<encode> will throw an |
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171 | exception when it encounters anything it cannot encode as CBOR. |
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172 | |
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173 | This option does not affect C<decode> in any way, and it is recommended to |
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174 | leave it off unless you know your communications partner. |
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175 | |
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176 | =item $cbor = $cbor->allow_sharable ([$enable]) |
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177 | |
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178 | =item $enabled = $cbor->get_allow_sharable |
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179 | |
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180 | If C<$enable> is true (or missing), then C<encode> will not double-encode |
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181 | values that have been seen before (e.g. when the same object, such as an |
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182 | array, is referenced multiple times), but instead will emit a reference to |
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183 | the earlier value. |
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184 | |
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185 | This means that such values will only be encoded once, and will not result |
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186 | in a deep cloning of the value on decode, in decoders supporting the value |
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187 | sharing extension. |
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188 | |
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189 | Detecting shared values incurs a runtime overhead when values are encoded |
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190 | that have a reference counter large than one, and might unnecessarily |
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191 | increase the encoded size, as potentially shared values are encode as |
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192 | sharable whether or not they are actually shared. |
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193 | |
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194 | At the moment, all shared values will be detected, even weird and unusual |
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195 | cases, such as an array with multiple "copies" of the I<same> scalar, |
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196 | which are hard but not impossible to create in Perl (L<Storable> for |
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197 | example doesn't handle these cases). If this turns out ot be a performance |
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198 | issue then future versions might limit the shared value detection to |
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199 | references only. |
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200 | |
|
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201 | If C<$enable> is false (the default), then C<encode> will encode |
|
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202 | exception when it encounters anything it cannot encode as CBOR. |
|
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203 | |
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204 | This option does not affect C<decode> in any way - shared values and |
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205 | references will always be decoded properly if present. It is recommended |
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206 | to leave it off unless you know your communications partner supports the |
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207 | value sharing extensions to CBOR (http://cbor.schmorp.de/value-sharing). |
|
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208 | |
| 162 | =item $cbor_data = $cbor->encode ($perl_scalar) |
209 | =item $cbor_data = $cbor->encode ($perl_scalar) |
| 163 | |
210 | |
| 164 | Converts the given Perl data structure (a scalar value) to its CBOR |
211 | Converts the given Perl data structure (a scalar value) to its CBOR |
| 165 | representation. |
212 | representation. |
| 166 | |
213 | |
| … | |
… | |
| 551 | Wrap CBOR data in CBOR: |
598 | Wrap CBOR data in CBOR: |
| 552 | |
599 | |
| 553 | my $cbor_cbor = encode_cbor |
600 | my $cbor_cbor = encode_cbor |
| 554 | CBOR::XS::tag 24, |
601 | CBOR::XS::tag 24, |
| 555 | encode_cbor [1, 2, 3]; |
602 | encode_cbor [1, 2, 3]; |
|
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603 | |
|
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604 | =head1 TAG HANDLING AND EXTENSIONS |
|
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605 | |
|
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606 | This section describes how this module handles specific tagged values and |
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607 | extensions. If a tag is not mentioned here, then the default handling |
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608 | applies (creating a CBOR::XS::Tagged object on decoding, and only encoding |
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609 | the tag when explicitly requested). |
|
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610 | |
|
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611 | Future versions of this module reserve the right to special case |
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612 | additional tags (such as bigfloat or base64url). |
|
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613 | |
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614 | =over 4 |
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615 | |
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616 | =item <unassigned> (perl-object, L<http://cbor.schmorp.de/perl-object>) |
|
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617 | |
|
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618 | These tags are automatically created for serialisable objects using the |
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619 | C<FREEZE/THAW> methods (the L<Types::Serialier> object serialisation |
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620 | protocol). |
|
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621 | |
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622 | =item <unassigned>, <unassigned> (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>) |
|
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623 | |
|
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624 | These tags are automatically decoded when encountered, resulting in |
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625 | shared values in the decoded object. They are only encoded, however, when |
|
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626 | C<allow_sharable> is enabled. |
|
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627 | |
|
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628 | =item 22098 (indirection, L<http://cbor.schmorp.de/indirection>) |
|
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629 | |
|
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630 | This tag is automatically generated when a reference are encountered (with |
|
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631 | the exception of hash and array refernces). It is converted to a reference |
|
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632 | when decoding. |
|
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633 | |
|
|
634 | =item 55799 (self-describe CBOR, RFC 7049) |
|
|
635 | |
|
|
636 | This value is not generated on encoding (unless explicitly requested by |
|
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637 | the user), and is simply ignored when decoding. |
|
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638 | |
|
|
639 | =back |
|
|
640 | |
| 556 | |
641 | |
| 557 | =head1 CBOR and JSON |
642 | =head1 CBOR and JSON |
| 558 | |
643 | |
| 559 | CBOR is supposed to implement a superset of the JSON data model, and is, |
644 | CBOR is supposed to implement a superset of the JSON data model, and is, |
| 560 | with some coercion, able to represent all JSON texts (something that other |
645 | with some coercion, able to represent all JSON texts (something that other |
