3 # Copyright 2004, 2005 by Jim Weirich (jim@weirichhouse.org).
6 # Permission is granted for use, copying, modification, distribution,
7 # and distribution of modified versions of this work as long as the
8 # above copyright notice is included.
11 # Provide a flexible and easy to use Builder for creating XML markup.
12 # See XmlBuilder for usage details.
14 require 'builder/xmlbase'
18 # Create XML markup easily. All (well, almost all) methods sent to
19 # an XmlMarkup object will be translated to the equivalent XML
20 # markup. Any method with a block will be treated as an XML markup
21 # tag with nested markup in the block.
23 # Examples will demonstrate this easier than words. In the
24 # following, +xm+ is an +XmlMarkup+ object.
26 # xm.em("emphasized") # => <em>emphasized</em>
27 # xm.em { xmm.b("emp & bold") } # => <em><b>emph & bold</b></em>
28 # xm.a("A Link", "href"=>"http://onestepback.org")
29 # # => <a href="http://onestepback.org">A Link</a>
30 # xm.div { br } # => <div><br/></div>
31 # xm.target("name"=>"compile", "option"=>"fast")
32 # # => <target option="fast" name="compile"\>
33 # # NOTE: order of attributes is not specified.
35 # xm.instruct! # <?xml version="1.0" encoding="UTF-8"?>
38 # xm.title("History") # <title>History</title>
41 # xm.comment! "HI" # <! -- HI -->
42 # xm.h1("Header") # <h1>Header</h1>
43 # xm.p("paragraph") # <p>paragraph</p>
49 # * The order that attributes are inserted in markup tags is
52 # * Sometimes you wish to insert text without enclosing tags. Use
53 # the <tt>text!</tt> method to accomplish this.
58 # xm.text! "line"; xm.br # line<br/>
59 # xm.text! "another line"; xmbr # another line<br/>
62 # * The special XML characters <, >, and & are converted to <,
63 # > and & automatically. Use the <tt><<</tt> operation to
64 # insert text without modification.
66 # * Sometimes tags use special characters not allowed in ruby
67 # identifiers. Use the <tt>tag!</tt> method to handle these
72 # xml.tag!("SOAP:Envelope") { ... }
76 # <SOAP:Envelope> ... </SOAP:Envelope>"
78 # <tt>tag!</tt> will also take text and attribute arguments (after
79 # the tag name) like normal markup methods. (But see the next
80 # bullet item for a better way to handle XML namespaces).
82 # * Direct support for XML namespaces is now available. If the
83 # first argument to a tag call is a symbol, it will be joined to
84 # the tag to produce a namespace:tag combination. It is easier to
85 # show this than describe it.
87 # xml.SOAP :Envelope do ... end
89 # Just put a space before the colon in a namespace to produce the
90 # right form for builder (e.g. "<tt>SOAP:Envelope</tt>" =>
91 # "<tt>xml.SOAP :Envelope</tt>")
93 # * XmlMarkup builds the markup in any object (called a _target_)
94 # that accepts the <tt><<</tt> method. If no target is given,
95 # then XmlMarkup defaults to a string target.
99 # xm = Builder::XmlMarkup.new
100 # result = xm.title("yada")
101 # # result is a string containing the markup.
104 # xm = Builder::XmlMarkup.new(buffer)
105 # # The markup is appended to buffer (using <<)
107 # xm = Builder::XmlMarkup.new(STDOUT)
108 # # The markup is written to STDOUT (using <<)
110 # xm = Builder::XmlMarkup.new
111 # x2 = Builder::XmlMarkup.new(:target=>xm)
112 # # Markup written to +x2+ will be send to +xm+.
114 # * Indentation is enabled by providing the number of spaces to
115 # indent for each level as a second argument to XmlBuilder.new.
116 # Initial indentation may be specified using a third parameter.
120 # xm = Builder.new(:indent=>2)
121 # # xm will produce nicely formatted and indented XML.
123 # xm = Builder.new(:indent=>2, :margin=>4)
124 # # xm will produce nicely formatted and indented XML with 2
125 # # spaces per indent and an over all indentation level of 4.
127 # builder = Builder::XmlMarkup.new(:target=>$stdout, :indent=>2)
128 # builder.name { |b| b.first("Jim"); b.last("Weirich) }
131 # # <first>Jim</first>
132 # # <last>Weirich</last>
135 # * The instance_eval implementation which forces self to refer to
136 # the message receiver as self is now obsolete. We now use normal
137 # block calls to execute the markup block. This means that all
138 # markup methods must now be explicitly send to the xml builder.
139 # For instance, instead of
141 # xml.div { strong("text") }
145 # xml.div { xml.strong("text") }
147 # Although more verbose, the subtle change in semantics within the
148 # block was found to be prone to error. To make this change a
149 # little less cumbersome, the markup block now gets the markup
150 # object sent as an argument, allowing you to use a shorter alias
155 # xml_builder = Builder::XmlMarkup.new
156 # xml_builder.div { |xml|
160 class XmlMarkup
< XmlBase
162 # Create an XML markup builder. Parameters are specified by an
165 # :target=><em>target_object</em>::
166 # Object receiving the markup. +out+ must respond to the
167 # <tt><<</tt> operator. The default is a plain string target.
169 # :indent=><em>indentation</em>::
170 # Number of spaces used for indentation. The default is no
171 # indentation and no line breaks.
173 # :margin=><em>initial_indentation_level</em>::
174 # Amount of initial indentation (specified in levels, not
177 # :escape_attrs=><b>OBSOLETE</em>::
178 # The :escape_attrs option is no longer supported by builder
179 # (and will be quietly ignored). String attribute values are
180 # now automatically escaped. If you need unescaped attribute
181 # values (perhaps you are using entities in the attribute
182 # values), then give the value as a Symbol. This allows much
183 # finer control over escaping attribute values.
185 def initialize(options
={})
186 indent
= options
[:indent] || 0
187 margin
= options
[:margin] || 0
188 super(indent
, margin
)
189 @target = options
[:target] || ""
192 # Return the target of the builder.
197 def comment
!(comment_text
)
198 _ensure_no_block block_given
?
199 _special("<!-- ", " -->", comment_text
, nil)
202 # Insert an XML declaration into the XML markup.
206 # xml.declare! :ELEMENT, :blah, "yada"
207 # # => <!ELEMENT blah "yada">
208 def declare
!(inst
, *args
, &block
)
210 @target << "<!#{inst}"
214 @target << %{ "#{arg}"} # " WART
222 _nested_structures(block
)
229 # Insert a processing instruction into the XML markup. E.g.
234 # #=> <?xml version="1.0" encoding="UTF-8"?>
235 # xml.instruct! :aaa, :bbb=>"ccc"
236 # #=> <?aaa bbb="ccc"?>
238 def instruct
!(directive_tag
=:xml, attrs
={})
239 _ensure_no_block block_given
?
240 if directive_tag
== :xml
241 a
= { :version=>"1.0", :encoding=>"UTF-8" }
242 attrs
= a
.merge attrs
245 "<?#{directive_tag}",
249 [:version, :encoding, :standalone])
252 # Insert a CDATA section into the XML markup.
256 # xml.cdata!("text to be included in cdata")
257 # #=> <![CDATA[text to be included in cdata]]>
260 _ensure_no_block block_given
?
261 _special("<![CDATA[", "]]>", text
, nil)
266 # NOTE: All private methods of a builder object are prefixed when
267 # a "_" character to avoid possible conflict with XML tag names.
269 # Insert text directly in to the builder's target.
274 # Insert special instruction.
275 def _special(open
, close
, data=nil, attrs
=nil, order
=[])
278 @target << data if data
279 _insert_attributes(attrs
, order
) if attrs
284 # Start an XML tag. If <tt>end_too</tt> is true, then the start
285 # tag is also the end tag (e.g. <br/>
286 def _start_tag(sym
, attrs
, end_too
=false)
288 _insert_attributes(attrs
)
289 @target << "/" if end_too
293 # Insert an ending tag.
295 @target << "</#{sym}>"
298 # Insert the attributes (given in the hash).
299 def _insert_attributes(attrs
, order
=[])
303 @target << %{ #{k}="#{_attr_value(v)}"} if v # " WART
306 @target << %{ #{k}="#{_attr_value(v)}"} unless order.member?(k) # " WART
310 def _attr_value(value
)
315 _escape_quote(value
.to_s
)
319 def _ensure_no_block(got_block
)
321 fail IllegalBlockError
,
322 "Blocks are not allowed on XML instructions"