Xml (XmlDoc function): Difference between revisions

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This function converts an <var>Xml</var>Doc to its textually represented XML document
This function converts an <var>Xml</var>Doc to its textually represented XML document
(this process is called '''serialization''',
(this process is called '''serialization''',
because the text representation of a document is called the '''serial'''
because the text representation of a document is called the '''serial''' form).
form).
==Syntax==
==Syntax==
{{Template:XmlDoc:Xml syntax}}
{{Template:XmlDoc:Xml syntax}}
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<td><var>Xml</var>Doc expression, whose content is serialized. </td></tr>
<td><var>Xml</var>Doc expression, whose content is serialized. </td></tr>
<tr><th>options</th>
<tr><th>options</th>
<td>Any combination of the following options (but single occurrences only): <br> <ul> <li><b>Allow<var>Xml</var>Decl</b> or <b>No<var>Xml</var>Decl</b>
<td>A blank delimited string that can contain one or more of the following options (but no repeats), which are identified below and described in greater detail in [[XmlDoc API serialization options|"XmlDoc API serialization options"]]:  
<p class="code">Allow<var>Xml</var>Decl, the default, produces the XML declaration (that is, <?xml&thinsp.version=...?>) if the declaration was set (see [[Version (XmlDoc property)|Version]]). No<var>Xml</var>Decl omits the XML declaration. <li><b>Indent</b> <i><b>n</b></i>
<ul>  
Inserts space characters (and line-ends, as described for the next option) into the serialized string such that if the string is broken at the line-ends and displayed as a tree, the display of each lower level in the subtree is indented ''n'' spaces from the previous level's starting point.
<li><b>AllowXmlDecl</b> or <b>NoXmlDecl</b><br>
If serialized output with an Indent value of 2 is displayed as a tree, the spacing is as in the following: <pre>     <top>      <leaf1 xx="yy">value</leaf1>       <sub>         <leaf2>value</leaf2>       </sub>     </top> </pre> <i>n</i> is a non-negative integer, and it maximum value (as of ''Sirius Mods'' version 7.0) is 254.
Whether or not the serialization will contain the "XML Declaration" (<code><?xml version=...?></code>), if the value of the [[Version (XmlDoc property)|Version]] property is a non-null string, if the <var>XmlDoc</var> is not empty,
One of the line-end options, below, must also be specified. <li>One of the '''line-end options''' below, to provide line breaks in the output after any of the following is serialized: <ul> <li>An element start-tag, if it has any non-text node children <li>An empty element tag, or an empty element end-tag <li>A processing instruction (PI) <li>A comment <li>A text node, if it has any siblings </ul>
and if the node selected by <var class="term">xpath</var> is the <var>Root</var> node. <var>AllowXmlDecl</var> is the default.  
</p>
 
<table class="syntaxNested">
<li><b>Indent <i>n</i></b><br>
<tr><th>CR</th>
Inserts space characters and line-ends into the serialized string such that if the string is broken at the line-ends and displayed as a tree, the display of each lower level in the subtree is indented ''n'' spaces from the previous level's starting point. You must also specify <code>CR</code>, <code>LF</code>, or <code>CRLF</code> (see below).
<td>Insert a carriage-return character as the line-end sequence in the above cases. </td></tr>
 
<tr><th>LF</th>
<li><b>CR</b> (carriage-return), <b>LF</b> (linefeed), or <b>CRLF</b> (carriage-return followed by a linefeed)<br>
<td>Insert a linefeed character as the line-end sequence in the above cases. </td></tr>
Inserts one of these line-end options to provide line breaks in the serialized output.  
<tr><th>CRLF</th>
 
<td>Insert a carriage-return character followed by a linefeed character as the line-end sequence in the above cases. </td></tr>
<li><b>NoEmptyElt</b><br>
</table>
Deprecated as of ''Sirius Mods'' version 7.0, this option ensures that all empty elements are serialized with a start tag followed by an end tag. The default is to serialize an empty element with an empty element tag (as in <code><middleName/></code>).
<p class="code"><br> <li><b>NoEmptyElt</b>
 
This indicates that an empty element is serialized with its start tag followed by an end tag. For example: <pre>    <middleName></middleName> </pre> If this option is not specified, the default is to serialize an empty element with an empty element tag: <pre>     <middleName/> </pre> <li><b>OmitNullElement</b>
<li><b>OmitNullElement</b><br>
An Element node that has no children and no Attributes will not be serialized, unless it is the top level Element in the subtree being serialized. The serialization of a child-less and Attribute-less Element is omitted, even if the Element's serialization would contain Namespace declarations in its start tag.
An <var>Element</var> node that has no children and no <var>Attributes</var> will not be serialized, unless it is the top level <var>Element</var> in the subtree being serialized.
If an Element node has no Attributes, but has (only) Element children (one or more), and all of its children are Attribute-less and child-less, then that parent Element is serialized, even though its content in the serialization is empty. That parent is serialized with a start tag and an end tag (and an inserted line separator, if called for by the serializing method's parameter options).
 
For example, if the Print method display of a particular <var>Xml</var>Doc object is the following when OmitNullElement is ''not'' specified: <pre>    <top>        <middle>          <empty/>          <p:empty2 xmlns:p="uri:stuff"/>        </middle>    </top> </pre>
<li><b>SortCanonical</b><br>
Here is the display of the <var>Xml</var>Doc with the OmitNullElement option specified: <pre>    <top>        <middle>        </middle>    </top> </pre>
 
The OmitNullElement option is available as of ''Sirius Mods'' version 7.3. <li><b>SortCanonical</b>
This deprecated option serializes namespace declarations and attributes in sorted order (from lowest to highest with Unicode code ordering).
This indicates that namespace declarations (based on the prefix being declared) and attributes (based on the namespace URI followed by the local name) are serialized in sorted order. This can be useful, for instance, when using the <var>Xml</var> method to serialize a portion of an XML document for a signature.
It is superseded by the [[Serial (XmlDoc/XmlNode function)|Serial]] method <var>ExclCanonical</var> option.  
The sort order for namespace declarations and attributes is from lowest to highest, and it uses the <var>Unicode</var> code ordering (for example, numbers are lower than letters).
</ul></td></tr>
This option was added in ''Sirius Mods'' version 6.9 as a step towards support for canonicalization. As of version 7.0, comprehensive support for canonicalized serialization is provided by the Serial method ExclCanonical option ([[??]] refid=exclcan.). </ul></td></tr>
</p>
</table>
</table>
==Usage notes==
==Usage notes==


<ul>
<ul>
<li>Options may be specified in any case, for example, you can use
<li>Options may be specified in any case, for example, you can use
either <tt>No<var>Xml</var>Decl</tt> or <tt>noxmldecl</tt>, interchangeably.
either <code>NoXmlDecl</code> or <code>noxmldecl</code>, interchangeably.
<li>The <i><var>Xml</var>Doc</i> method object must be well-formed (that is,
<li>The <var>Xml</var>Doc method object must be well-formed (that is,
it must contain an Element node).
it must contain an <var>Element</var> node).
For more information about well-formed documents, see [[??]] refid=welform..
For more information, see  
[[XML processing in Janus SOAP#Well-formed documents and validation|"Well-formed documents and validation"]].
<li>Since the result of the <var>Xml</var> function has UTF-8 encoding, you
<li>Since the result of the <var>Xml</var> function has UTF-8 encoding, you
cannot treat it as an EBCDIC string: for example, printing the string
cannot treat it as an EBCDIC string: for example, printing the string
will not produce displayable characters.
will not produce displayable characters.
The "See Also" section below mentions some methods for obtaining
The [[#See also|"See Also"]] section below mentions some methods for obtaining
an EBCDIC serialization of an <var>Xml</var>Doc.
an EBCDIC serialization of an <var>XmlDoc</var>.
<li>You can use the Print method
<li>You can use the [[Print (XmlDoc/XmlNode subroutine)|Print]]
(??[[Print (XmlDoc/XmlNode subroutine)|Print]])
method to display a document on the terminal,
to display a document on the terminal,
or to ''capture'' a displayable version of a document, but <var>Print</var> is
or to '''capture''' a displayable version of a document, but Print is
used to insert line breaks and optional indentation, which may not be an
used to insert line breaks and optional indentation, which may not be an
accurate serialization of an <var>Xml</var>Doc.
accurate serialization of an <var>XmlDoc</var>.
<li>Using one of the line-end character options (CR, LF, CRLF) produces output
that is analogous to the BothCompact option of the Print method.
<li>If one of the line-end
(<tt>CR</tt>, <tt>LF</tt>, <tt>CRLF</tt>) options or if
<tt>Indent</tt> is specified, and an element to be serialized has the
<tt>xml:space="preserve"</tt> attribute, then
within the serialization of that element and its descendants, no line-end
(nor indentation) characters are inserted to provide readability.
 
In addition, the <tt>xml:space="default"</tt> attribute has no effect
under these options:
specified by itself, it does not influence serialization, nor
does it cause resumption of readability line-ends or indents if they were
suspended by a containing <tt>xml:space="preserve"</tt>.
<li>As of version 6.7, the <var>Xml</var> method uses the hexadecimal
character references specified in the XML Canonicalization specification
(:hp0 color=SirLink.http://www.w3.org/TR/xml-c14n:ehp0.)  to
display the following characters:
<ul>
<li>For Attribute nodes: tab, carriage return, and linefeed
<li>For Text nodes: carriage return
</ul>
 
Since the character references are not subject to the standard XML whitespace
normalization ([[??]] refid=normwhi.),
a serialized document (or subtree) that is then deserialized
will retain this whitespace.
 
These character references are used:
<dl>
<dt>tab
<dd>&amp;#x9;
<dt>CR
<dd>&amp;#xD;
<dt>LF
<dd>&amp;#xA;
</dl>


The EBCDIC and corresponding ASCII encodings of the characters is:
<li>As of ''Sirius Mods'' version 7.6, <var>Attribute</var> values are always serialized
<dl>
<dt>&thinsp.
<dd>EBCDIC    ASCII
<dt>tab
<dd>X'05'          X'09'
<dt>CR
<dd>X'0D'          X'0D'
<dt>LF
<dd>X'25'          X'0A'
</dl>
<li>As of ''Sirius Mods'' version 7.6, ''Attribute values'' are always serialized
within double-quotation-mark (<tt>"</tt>) delimiters,
within double-quotation-mark (<tt>"</tt>) delimiters,
and a double-quotation mark character in an attribute value is serialized
and a double-quotation mark character in an attribute value is serialized
as <tt>&amp;quot;</tt>.
as <code>&amp;quot;</code>.
Prior to version 7.6, this convention was not strictly observed.
Prior to version 7.6, this convention was not strictly observed.


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==Examples==
==Examples==
<ul>
<ul>
<li>The [[Janus Sockets]]R documents the HttpRequest object, whose
<li>The [[AddXml]] method of the [[HttpRequest]] class
Add<var>Xml</var> method has nearly the same options as the <var>Xml</var> function;
has nearly the same options as the <var>Xml</var> function.
the following fragment serializes an <var>Xml</var>Doc and sends it
The following fragment serializes an <var>XmlDoc</var> and sends it
as a request to a Web server.
as a request to a web server.


Note that if you use the <var>Xml</var> function and $Sock_Send directly,
Note that if you use the <var>Xml</var> function and [[$Sock_Send]] directly,
instead of using an HTTP helper object, always use
instead of using an [[HTTP Helper]] object, always use
the BINARY option of $Sock_Send, because the
the >var>BINARY</var> option of <var>$Sock_Send</var>, because the
result of the
result of the <var>Xml</var> function is UTF-8, rather than EBCDIC.
<var>Xml</var> function is UTF-8, rather than EBCDIC.
<p class="code"> %httpreq object HttpRequest
<p class="code">%httpreq object HttpRequest
%httpresp object HttpResponse
%httpresp object HttpResponse
%doc object XmlDoc
%doc object XmlDoc
%httpreq = New
%httpreq = New
%doc = New
%doc = New
%doc:LoadXml('<inquire><stock>IBM</stock>' With -
%doc:LoadXml('<inquire><stock>IBM</stock>' With -
    <dateRange/></inquire>', 'NoEmptyElt')
  <dateRange/></inquire>', 'NoEmptyElt')
   
   
%httpreq:URL = 'foo.com/bar'
%httpreq:URL = 'foo.com/bar'
%httpreq:AddXml(%doc)
%httpreq:AddXml(%doc)
%httpresp = %httpreq:Post('HTTP_CLIENT')
%httpresp = %httpreq:Post('HTTP_CLIENT')
</p>
</p>
<li>The following fragment is a simple example for serializing an <var>Xml</var>Doc, which
<li>The following fragment is a simple example for serializing an <var>XmlDoc</var>, which
could then, for example, be sent on a transport such as MQ:
could then, for example, be sent on a transport such as MQ:
<p class="code">%s Longstring
<p class="code"> %s Longstring
%s = %doc:Xml
%s = %doc:Xml
</p>
</p>
</ul>
</ul>


===Request-Cancellation Errors===
===Request-cancellation errors===
<ul>
<ul>
<li><var>XmlDoc</var> does not contain an Element.
<li><var>XmlDoc</var> does not contain an <var>Element</var>.
<li><i>Options</i> is invalid.
<li>An <var class="term">options</var> setting is invalid.
<li>Insufficient free space exists in CCATEMP.
<li>Insufficient free space exists in CCATEMP.
</ul>
</ul>
Line 158: Line 107:


<ul>
<ul>
<li>Use ??[[Print (XmlDoc/XmlNode subroutine)|Print]] to display an XML document for debugging.
<li>Use [[Print (XmlDoc/XmlNode subroutine)|Print]] to display an XML document for debugging.
<li>Use ??[[Serial (XmlDoc/XmlNode function)|Serial]] with the EBCDIC option to obtain an EBCDIC serialization of
<li>Use [[Serial (XmlDoc/XmlNode function)|Serial]] with the EBCDIC option to obtain an EBCDIC serialization of
an XML document.
an XML document.
<li>Use ??[[WebSend (XmlDoc subroutine)|WebSend]]
<li>Use [[WebSend (XmlDoc subroutine)|WebSend]]
to serialize an <var>Xml</var>Doc and send it as an HTTP response using [[Janus Web Server]].
to serialize an <var>XmlDoc</var> and send it as an HTTP response using [[Janus Web Server]].
<li>The string deserialization functions are ??[[LoadXml (XmlDoc/XmlNode function)|LoadXml]]
<li>The string deserialization functions are [[LoadXml (XmlDoc/XmlNode function)|LoadXml]]
and ??[[WebReceive (XmlDoc function)|WebReceive]].
and [[WebReceive (XmlDoc function)|WebReceive]].
</ul>
</ul>

Revision as of 03:20, 16 February 2011

Serialize XmlDoc as UTF-8 string (XmlDoc class)


This function converts an XmlDoc to its textually represented XML document (this process is called serialization, because the text representation of a document is called the serial form).

Syntax

%string = doc:Xml[( [options])]

Syntax terms

utf8Str The string serialization of the XmlDoc, encoded in UTF-8.
doc XmlDoc expression, whose content is serialized.
options A blank delimited string that can contain one or more of the following options (but no repeats), which are identified below and described in greater detail in "XmlDoc API serialization options":
  • AllowXmlDecl or NoXmlDecl
    Whether or not the serialization will contain the "XML Declaration" (<?xml version=...?>), if the value of the Version property is a non-null string, if the XmlDoc is not empty, and if the node selected by xpath is the Root node. AllowXmlDecl is the default.
  • Indent n
    Inserts space characters and line-ends into the serialized string such that if the string is broken at the line-ends and displayed as a tree, the display of each lower level in the subtree is indented n spaces from the previous level's starting point. You must also specify CR, LF, or CRLF (see below).
  • CR (carriage-return), LF (linefeed), or CRLF (carriage-return followed by a linefeed)
    Inserts one of these line-end options to provide line breaks in the serialized output.
  • NoEmptyElt
    Deprecated as of Sirius Mods version 7.0, this option ensures that all empty elements are serialized with a start tag followed by an end tag. The default is to serialize an empty element with an empty element tag (as in <middleName/>).
  • OmitNullElement
    An Element node that has no children and no Attributes will not be serialized, unless it is the top level Element in the subtree being serialized.
  • SortCanonical
    This deprecated option serializes namespace declarations and attributes in sorted order (from lowest to highest with Unicode code ordering). It is superseded by the Serial method ExclCanonical option.

Usage notes

  • Options may be specified in any case, for example, you can use either NoXmlDecl or noxmldecl, interchangeably.
  • The XmlDoc method object must be well-formed (that is, it must contain an Element node). For more information, see "Well-formed documents and validation".
  • Since the result of the Xml function has UTF-8 encoding, you cannot treat it as an EBCDIC string: for example, printing the string will not produce displayable characters. The "See Also" section below mentions some methods for obtaining an EBCDIC serialization of an XmlDoc.
  • You can use the Print method to display a document on the terminal, or to capture a displayable version of a document, but Print is used to insert line breaks and optional indentation, which may not be an accurate serialization of an XmlDoc.
  • As of Sirius Mods version 7.6, Attribute values are always serialized within double-quotation-mark (") delimiters, and a double-quotation mark character in an attribute value is serialized as &quot;. Prior to version 7.6, this convention was not strictly observed.

Examples

  • The AddXml method of the HttpRequest class has nearly the same options as the Xml function. The following fragment serializes an XmlDoc and sends it as a request to a web server. Note that if you use the Xml function and $Sock_Send directly, instead of using an HTTP Helper object, always use the >var>BINARY option of $Sock_Send, because the result of the Xml function is UTF-8, rather than EBCDIC.

    %httpreq object HttpRequest %httpresp object HttpResponse %doc object XmlDoc %httpreq = New %doc = New %doc:LoadXml('<inquire><stock>IBM</stock>' With - <dateRange/></inquire>', 'NoEmptyElt') %httpreq:URL = 'foo.com/bar' %httpreq:AddXml(%doc) %httpresp = %httpreq:Post('HTTP_CLIENT')

  • The following fragment is a simple example for serializing an XmlDoc, which could then, for example, be sent on a transport such as MQ:

    %s Longstring %s = %doc:Xml

Request-cancellation errors

  • XmlDoc does not contain an Element.
  • An options setting is invalid.
  • Insufficient free space exists in CCATEMP.


See also

  • Use Print to display an XML document for debugging.
  • Use Serial with the EBCDIC option to obtain an EBCDIC serialization of an XML document.
  • Use WebSend to serialize an XmlDoc and send it as an HTTP response using Janus Web Server.
  • The string deserialization functions are LoadXml and WebReceive.