Difference between revisions of "Serialization"
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This page is part of the [[XQuery|XQuery Portal]]. | This page is part of the [[XQuery|XQuery Portal]]. | ||
− | |||
− | |||
− | |||
− | * | + | Serialization parameters define how XQuery items and XML nodes will be ''serialized'' (i.e., returned to the client or an API, usually in textual form). The official parameters are defined in the [https://www.w3.org/TR/xslt-xquery-serialization-31 W3C XQuery Serialization 3.1] document. In BaseX, they can be: |
− | * | + | |
− | + | * included in the [[XQuery_3.0#Serialization|prolog of the XQuery expression]]; | |
− | ** | + | * specified in XQuery functions ({{Function|File|file:write}}, {{Function|Database|db:export}}, [https://www.w3.org/TR/xpath-functions-31/#func-serialize fn:serialize()]); |
− | * | + | * specified in [[REST#Parameters|REST query parameters]]; |
− | + | * specified in [[RESTXQ#Output|RESTXQ output annotations]]; | |
− | + | * set via the {{Option|SERIALIZER}} option before running a query; | |
− | + | * set via the {{Option|EXPORTER}} option before exporting a database; or | |
+ | * supplied with the {{Code|-s}} flag of the BaseX [[Command-Line Options#BaseX Standalone|command-line]] clients. | ||
+ | |||
+ | The namespace for serialization parameters is statically bound to the {{Code|output}} prefix. This means that it need not (but may) be declared in the query prolog: | ||
+ | |||
+ | <syntaxhighlight lang="xquery"> | ||
+ | declare namespace output = 'http://www.w3.org/2010/xslt-xquery-serialization'; | ||
+ | declare option output:method 'text'; | ||
+ | <xml>Hi there</xml> | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | Due to the wide range of ways how parameters can be supplied, we deliberately ignored one rule of the specification, which requires non-official features to be defined in a non-null namespace URI. In the following, we will indicate which features are specific to our implementation. | ||
=Parameters= | =Parameters= | ||
− | The following | + | The following serialization parameters are supported by BaseX (further details can be looked up in the official specification): |
{| class="wikitable sortable" width="100%" | {| class="wikitable sortable" width="100%" | ||
|- valign="top" | |- valign="top" | ||
! width="140" | Parameter | ! width="140" | Parameter | ||
− | ! | + | ! Description |
! Allowed | ! Allowed | ||
! Default | ! Default | ||
|- valign="top" | |- valign="top" | ||
| {{Code|method}} | | {{Code|method}} | ||
− | | Specifies the serialization method | + | | Specifies the serialization method. {{Code|xml}}, {{Code|xhtml}}, {{Code|html}}, {{Code|text}} and {{Code|adaptive}} are part of the official specification. For more details on {{Code|basex}}, {{Code|csv}} and {{Code|json}}, see [[XQuery Extensions#Serialization|XQuery Extensions]]. |
− | + | | {{Code|xml}}, {{Code|xhtml}}, {{Code|html}}, {{Code|text}}, {{Code|json}}, {{Code|adaptive}}, {{Code|csv}}, {{Code|basex}} | |
− | + | | {{Code|basex}} | |
− | |||
− | |||
− | | {{Code|xml}}, {{Code|xhtml}}, {{Code|html}}, {{Code|text}}, {{Code|json}}, {{Code|csv}}, {{Code| | ||
− | | {{Code| | ||
|- valign="top" | |- valign="top" | ||
| {{Code|version}} | | {{Code|version}} | ||
| Specifies the version of the serialization method. | | Specifies the version of the serialization method. | ||
− | + | | xml/xhtml: {{Code|1.0}}, {{Code|1.1}}<br/>html: {{Code|4.0}}, {{Code|4.01}}, {{Code|5.0}}<br/> | |
| {{Code|1.0}} | | {{Code|1.0}} | ||
|- valign="top" | |- valign="top" | ||
Line 45: | Line 49: | ||
| {{Code|item-separator}} | | {{Code|item-separator}} | ||
| Determines a string to be used as item separator. If a separator is specified, the default separation of atomic values with single whitespaces will be skipped. | | Determines a string to be used as item separator. If a separator is specified, the default separation of atomic values with single whitespaces will be skipped. | ||
− | | ''arbitrary strings'' | + | | ''arbitrary strings'' |
| ''empty'' | | ''empty'' | ||
|- valign="top" | |- valign="top" | ||
| {{Code|encoding}} | | {{Code|encoding}} | ||
| Encoding to be used for outputting the data. | | Encoding to be used for outputting the data. | ||
− | | ''[ | + | | ''[https://docs.oracle.com/javase/8/docs/technotes/guides/intl/encoding.doc.html all encodings supported by Java]'' |
| {{Code|UTF-8}} | | {{Code|UTF-8}} | ||
|- valign="top" | |- valign="top" | ||
Line 97: | Line 101: | ||
| | | | ||
| {{Code|application/xml}} | | {{Code|application/xml}} | ||
+ | |- valign="top" | ||
+ | | {{Code|parameter-document}} | ||
+ | | Parses the value as XML document with additional serialization parameters (see the [https://www.w3.org/TR/xslt-xquery-serialization-31/#serparams-in-xdm-instance Serialization Specification] for more details). | ||
+ | | | ||
+ | | | ||
|- valign="top" | |- valign="top" | ||
| {{Code|use-character-maps}} | | {{Code|use-character-maps}} | ||
− | | Defines character mappings | + | | Defines character mappings. May only occur in documents parsed with {{Code|parameter-document}}. |
| | | | ||
| | | | ||
Line 114: | Line 123: | ||
|- valign="top" | |- valign="top" | ||
| {{Code|include-content-type}} | | {{Code|include-content-type}} | ||
− | | | + | | Inserts a {{Code|meta}} content-type element into the head element if the result is output as HTML<br />Example: <code><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head></code>. The head element must already exist or nothing will be added. Any existing {{Code|meta}} content-type elements will be removed. |
| {{Code|yes}}, {{Code|no}} | | {{Code|yes}}, {{Code|no}} | ||
− | | {{Code| | + | | {{Code|yes}} |
|} | |} | ||
Line 124: | Line 133: | ||
|- valign="top" | |- valign="top" | ||
! width="140" | Parameter | ! width="140" | Parameter | ||
− | ! | + | ! Description |
! Allowed | ! Allowed | ||
! Default | ! Default | ||
Line 137: | Line 146: | ||
| see [[JSON Module]] | | see [[JSON Module]] | ||
| | | | ||
− | |||
− | |||
− | |||
− | |||
− | |||
|- valign="top" | |- valign="top" | ||
| {{Code|tabulator}} | | {{Code|tabulator}} | ||
Line 152: | Line 156: | ||
| ''positive number'' | | ''positive number'' | ||
| {{Code|2}} | | {{Code|2}} | ||
− | |||
− | |||
− | |||
− | |||
− | |||
|- valign="top" | |- valign="top" | ||
| {{Code|newline}} | | {{Code|newline}} | ||
Line 167: | Line 166: | ||
| ''positive number'' | | ''positive number'' | ||
| {{Code|-1}} | | {{Code|-1}} | ||
+ | |- valign="top" | ||
+ | | {{Code|binary}} | ||
+ | | Indicates if items of binary type are output in their native byte representation. Only applicable to the <code>base</code> serialization method. | ||
+ | | {{Code|yes}}, {{Code|no}} | ||
+ | | {{Code|yes}} | ||
|} | |} | ||
The {{Code|csv}} and {{Code|json}} parameters are supplied with a list of options. Option names and values are combined with <code>=</code>, several options are separated by <code>,</code>: | The {{Code|csv}} and {{Code|json}} parameters are supplied with a list of options. Option names and values are combined with <code>=</code>, several options are separated by <code>,</code>: | ||
− | + | <syntaxhighlight lang="xquery"> | |
− | < | ||
− | |||
− | |||
declare option output:method "csv"; | declare option output:method "csv"; | ||
declare option output:csv "header=yes, separator=semicolon"; | declare option output:csv "header=yes, separator=semicolon"; | ||
Line 187: | Line 188: | ||
</record> | </record> | ||
</csv> | </csv> | ||
− | </ | + | </syntaxhighlight> |
+ | |||
+ | If {{Code|fn:serialize}} is called, output-specific parameters can be supplied via nested options: | ||
+ | |||
+ | <syntaxhighlight lang="xquery"> | ||
+ | serialize( | ||
+ | <csv> | ||
+ | <record> | ||
+ | <Name>John</Name> | ||
+ | <City>Newton</City> | ||
+ | </record> | ||
+ | <record> | ||
+ | <Name>Jack</Name> | ||
+ | <City>Oldtown</City> | ||
+ | </record> | ||
+ | </csv>, | ||
+ | map { | ||
+ | 'method': 'csv', | ||
+ | 'csv': map { 'header': 'yes', 'separator': ';' } | ||
+ | } | ||
+ | ) | ||
+ | </syntaxhighlight> | ||
'''Result''': | '''Result''': | ||
− | < | + | <syntaxhighlight lang="xml"> |
Name;City | Name;City | ||
John;Newton | John;Newton | ||
Jack;Oldtown | Jack;Oldtown | ||
− | </ | + | </syntaxhighlight> |
+ | |||
+ | =Character mappings= | ||
+ | |||
+ | Character maps allow a specific character in the instance of the data model to be replaced with a specified string of characters during serialization. The string that is substituted is output "as is," and the serializer performs no checks that the resulting document is well-formed. This may only occur in documents parsed with {{Code|parameter-document}}. If a character is mapped, then it is not subjected to XML or HTML escaping. For details refer to section [https://www.w3.org/TR/2015/CR-xslt-xquery-serialization-31-20151217/#character-maps 11 Character maps] in the [https://www.w3.org/TR/xslt-xquery-serialization-31 W3C XQuery Serialization 3.1] document | ||
+ | |||
+ | This example maps the Unicode U+00A0 NO-BREAK SPACE as &#160; (without the serialization parameter, the Unicode character would be output): | ||
+ | |||
+ | '''Example query''': | ||
+ | <syntaxhighlight lang="xquery"> | ||
+ | declare option output:parameter-document "map.xml"; | ||
+ | <x>&#xA0;</x> | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | '''Example parameter-document''': | ||
+ | <syntaxhighlight lang="xml"> | ||
+ | <serialization-parameters | ||
+ | xmlns="http://www.w3.org/2010/xslt-xquery-serialization"> | ||
+ | <use-character-maps> | ||
+ | <character-map character="&#160;" map-string="&amp;#160;"/> | ||
+ | </use-character-maps> | ||
+ | </serialization-parameters> | ||
+ | </syntaxhighlight> | ||
=Changelog= | =Changelog= | ||
+ | |||
+ | ;Version 9.2 | ||
+ | |||
+ | * Updated: New default value for {{Code|include-content-type}} is {{Code|yes}}. | ||
+ | |||
+ | ;Version 8.4 | ||
+ | |||
+ | * Added: Serialization parameter {{Code|binary}}. | ||
+ | * Updated: New serialization method <code>basex</code>. By default, items of binary type are now output in their native byte representation. The method <code>raw</code> was removed. | ||
+ | |||
+ | ;Version 8.0 | ||
+ | |||
+ | * Added: Support for {{Code|use-character-maps}} and {{Code|parameter-document}}. | ||
+ | * Added: Serialization method {{Code|adaptive}}. | ||
+ | * Updated: {{Code|adaptive}} is new default method (before: {{Code|xml}}). | ||
+ | * Removed: {{Code|format}}, {{Code|wrap-prefix}}, {{Code|wrap-uri}}. | ||
;Version 7.8.2 | ;Version 7.8.2 | ||
− | * Added: {{Code|limit}}: Stops serialization after the specified number of bytes has been serialized | + | * Added: {{Code|limit}}: Stops serialization after the specified number of bytes has been serialized. |
;Version 7.8 | ;Version 7.8 | ||
− | * Added: {{Code|csv}} and {{Code|json}} serialization parameters | + | * Added: {{Code|csv}} and {{Code|json}} serialization parameters. |
− | * Removed: {{Code|separator}} option (use {{Code|item-separator}} instead) | + | * Removed: {{Code|separator}} option (use {{Code|item-separator}} instead). |
;Version 7.7.2 | ;Version 7.7.2 | ||
− | * Added: {{Code|csv}} serialization method | + | * Added: {{Code|csv}} serialization method. |
− | * Added: temporary serialization methods {{Code|csv-header}}, {{Code|csv-separator}}, {{Code|json-unescape}}, {{Code|json-spec}}, {{Code|json-format}} | + | * Added: temporary serialization methods {{Code|csv-header}}, {{Code|csv-separator}}, {{Code|json-unescape}}, {{Code|json-spec}}, {{Code|json-format}}. |
;Version 7.5 | ;Version 7.5 | ||
− | * Added: official {{Code|item-separator}} and {{Code|html-version}} parameter | + | * Added: official {{Code|item-separator}} and {{Code|html-version}} parameter. |
− | * Updated: <code>method=html5</code> removed; serializers updated with the [ | + | * Updated: <code>method=html5</code> removed; serializers updated with the [https://www.w3.org/TR/2013/WD-xslt-xquery-serialization-30-20130108/ latest version of the specification], using <code>method=html</code> and <code>version=5.0</code>. |
;Version 7.2 | ;Version 7.2 | ||
− | * Added: {{Code|separator}} parameter | + | * Added: {{Code|separator}} parameter. |
;Version 7.1 | ;Version 7.1 | ||
− | * Added: {{Code|newline}} parameter | + | * Added: {{Code|newline}} parameter. |
;Version 7.0 | ;Version 7.0 | ||
− | * Added: Serialization parameters added to [[REST API]]; JSON/JsonML/raw methods | + | * Added: Serialization parameters added to [[REST API]]; JSON/JsonML/raw methods. |
Revision as of 09:28, 29 July 2020
This page is part of the XQuery Portal.
Serialization parameters define how XQuery items and XML nodes will be serialized (i.e., returned to the client or an API, usually in textual form). The official parameters are defined in the W3C XQuery Serialization 3.1 document. In BaseX, they can be:
- included in the prolog of the XQuery expression;
- specified in XQuery functions (
file:write
,db:export
, fn:serialize()); - specified in REST query parameters;
- specified in RESTXQ output annotations;
- set via the
SERIALIZER
option before running a query; - set via the
EXPORTER
option before exporting a database; or - supplied with the
-s
flag of the BaseX command-line clients.
The namespace for serialization parameters is statically bound to the output
prefix. This means that it need not (but may) be declared in the query prolog:
<syntaxhighlight lang="xquery"> declare namespace output = 'http://www.w3.org/2010/xslt-xquery-serialization'; declare option output:method 'text'; <xml>Hi there</xml> </syntaxhighlight>
Due to the wide range of ways how parameters can be supplied, we deliberately ignored one rule of the specification, which requires non-official features to be defined in a non-null namespace URI. In the following, we will indicate which features are specific to our implementation.
Parameters
The following serialization parameters are supported by BaseX (further details can be looked up in the official specification):
Parameter | Description | Allowed | Default |
---|---|---|---|
method
|
Specifies the serialization method. xml , xhtml , html , text and adaptive are part of the official specification. For more details on basex , csv and json , see XQuery Extensions.
|
xml , xhtml , html , text , json , adaptive , csv , basex
|
basex
|
version
|
Specifies the version of the serialization method. | xml/xhtml: 1.0 , 1.1 html: 4.0 , 4.01 , 5.0 |
1.0
|
html-version
|
Specifies the version of the HTML serialization method. | 4.0 , 4.01 , 5.0
|
4.0
|
item-separator
|
Determines a string to be used as item separator. If a separator is specified, the default separation of atomic values with single whitespaces will be skipped. | arbitrary strings | empty |
encoding
|
Encoding to be used for outputting the data. | all encodings supported by Java | UTF-8
|
indent
|
Adjusts whitespaces to make the output better readable. | yes , no
|
yes
|
cdata-section-elements
|
List of elements to be output as CDATA, separated by whitespaces. Example: <text><![CDATA[ <> ]]></text>
|
||
omit-xml-declaration
|
Omits the XML declaration, which is serialized before the actual query result Example: <?xml version="1.0" encoding="UTF-8"?>
|
yes , no
|
yes
|
standalone
|
Prints or omits the "standalone" attribute in the XML declaration. | yes , no , omit
|
omit
|
doctype-system
|
Introduces the output with a document type declaration and the given system identifier. Example: <!DOCTYPE x SYSTEM "entities.dtd">
|
||
doctype-public
|
If doctype-system is specified, adds a public identifier.Example: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
|
||
undeclare-prefixes
|
Undeclares prefixes in XML 1.1. | yes , no
|
no
|
normalization-form
|
Specifies a normalization form. BaseX supports Form C (NFC ).
|
NFC , none
|
NFC
|
media-type
|
Specifies the media type. | application/xml
| |
parameter-document
|
Parses the value as XML document with additional serialization parameters (see the Serialization Specification for more details). | ||
use-character-maps
|
Defines character mappings. May only occur in documents parsed with parameter-document .
|
||
byte-order-mark
|
Prints a byte-order-mark before starting serialization. | yes , no
|
no
|
escape-uri-attributes
|
Escapes URI information in certain HTML attributes Example: <a href="%C3%A4%C3%B6%C3%BC">äöü<a>
|
yes , no
|
no
|
include-content-type
|
Inserts a meta content-type element into the head element if the result is output as HTMLExample: <head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head> . The head element must already exist or nothing will be added. Any existing meta content-type elements will be removed.
|
yes , no
|
yes
|
BaseX provides some additional serialization parameters:
Parameter | Description | Allowed | Default |
---|---|---|---|
csv
|
Defines the way how data is serialized as CSV. | see CSV Module | |
json
|
Defines the way how data is serialized as JSON. | see JSON Module | |
tabulator
|
Uses tab characters (\t ) instead of spaces for indenting elements.
|
yes , no
|
no
|
indents
|
Specifies the number of characters to be indented. | positive number | 2
|
newline
|
Specifies the type of newline to be used as end-of-line marker. | \n , \r\n , \r
|
system dependent |
limit
|
Stops serialization after the specified number of bytes has been serialized. If a negative number is specified, everything will be output. | positive number | -1
|
binary
|
Indicates if items of binary type are output in their native byte representation. Only applicable to the base serialization method.
|
yes , no
|
yes
|
The csv
and json
parameters are supplied with a list of options. Option names and values are combined with =
, several options are separated by ,
:
<syntaxhighlight lang="xquery"> declare option output:method "csv"; declare option output:csv "header=yes, separator=semicolon"; <csv>
<record> <Name>John</Name> <City>Newton</City> </record> <record> <Name>Jack</Name> <City>Oldtown</City> </record>
</csv> </syntaxhighlight>
If fn:serialize
is called, output-specific parameters can be supplied via nested options:
<syntaxhighlight lang="xquery"> serialize(
<csv> <record> <Name>John</Name> <City>Newton</City> </record> <record> <Name>Jack</Name> <City>Oldtown</City> </record> </csv>, map { 'method': 'csv', 'csv': map { 'header': 'yes', 'separator': ';' } }
) </syntaxhighlight>
Result: <syntaxhighlight lang="xml"> Name;City John;Newton Jack;Oldtown </syntaxhighlight>
Character mappings
Character maps allow a specific character in the instance of the data model to be replaced with a specified string of characters during serialization. The string that is substituted is output "as is," and the serializer performs no checks that the resulting document is well-formed. This may only occur in documents parsed with parameter-document
. If a character is mapped, then it is not subjected to XML or HTML escaping. For details refer to section 11 Character maps in the W3C XQuery Serialization 3.1 document
This example maps the Unicode U+00A0 NO-BREAK SPACE as   (without the serialization parameter, the Unicode character would be output):
Example query: <syntaxhighlight lang="xquery"> declare option output:parameter-document "map.xml"; <x> </x> </syntaxhighlight>
Example parameter-document: <syntaxhighlight lang="xml"> <serialization-parameters
xmlns="http://www.w3.org/2010/xslt-xquery-serialization"> <use-character-maps> <character-map character=" " map-string="&#160;"/> </use-character-maps>
</serialization-parameters> </syntaxhighlight>
Changelog
- Version 9.2
- Updated: New default value for
include-content-type
isyes
.
- Version 8.4
- Added: Serialization parameter
binary
. - Updated: New serialization method
basex
. By default, items of binary type are now output in their native byte representation. The methodraw
was removed.
- Version 8.0
- Added: Support for
use-character-maps
andparameter-document
. - Added: Serialization method
adaptive
. - Updated:
adaptive
is new default method (before:xml
). - Removed:
format
,wrap-prefix
,wrap-uri
.
- Version 7.8.2
- Added:
limit
: Stops serialization after the specified number of bytes has been serialized.
- Version 7.8
- Added:
csv
andjson
serialization parameters. - Removed:
separator
option (useitem-separator
instead).
- Version 7.7.2
- Added:
csv
serialization method. - Added: temporary serialization methods
csv-header
,csv-separator
,json-unescape
,json-spec
,json-format
.
- Version 7.5
- Added: official
item-separator
andhtml-version
parameter. - Updated:
method=html5
removed; serializers updated with the latest version of the specification, usingmethod=html
andversion=5.0
.
- Version 7.2
- Added:
separator
parameter.
- Version 7.1
- Added:
newline
parameter.
- Version 7.0
- Added: Serialization parameters added to REST API; JSON/JsonML/raw methods.