Class: Homebrew::Livecheck::Strategy::Xml
- Defined in:
- livecheck/strategy/xml.rb
Overview
The Xml strategy fetches content at a URL, parses it as XML using
REXML
, and provides the REXML::Document
to a strategy
block.
If a regex is present in the livecheck
block, it should be passed
as the second argument to the strategy
block.
This is a generic strategy that doesn’t contain any logic for finding
versions, as the structure of XML data varies. Instead, a strategy
block must be used to extract version information from the XML data.
For more information on how to work with an REXML::Document
object,
please refer to the REXML::Document
and REXML::Element
documentation.
This strategy is not applied automatically and it is necessary to use
strategy :xml
in a livecheck
block (in conjunction with a
strategy
block) to use it.
This strategy’s Xml.find_versions method can be used in other strategies that work with XML content, so it should only be necessary to write the version-finding logic that works with the parsed XML data.
Constant Summary collapse
- NICE_NAME =
"XML"
- PRIORITY =
A priority of zero causes livecheck to skip the strategy. We do this for Homebrew::Livecheck::Strategy::Xml so we can selectively apply it only when a strategy block is provided in a
livecheck
block. 0
- URL_MATCH_REGEX =
The
Regexp
used to determine if the strategy applies to the URL. %r{^https?://}i
Class Method Summary collapse
-
.element_text(element, child_path = nil) ⇒ String?
Retrieves the stripped inner text of an
REXML
element. -
.find_versions(url:, regex: nil, provided_content: nil, homebrew_curl: false, **_unused, &block) ⇒ Hash{Symbol => T.untyped}
Checks the XML content at the URL for versions, using the provided
strategy
block to extract version information. -
.match?(url) ⇒ Boolean
Whether the strategy can be applied to the provided URL.
-
.parse_xml(content) ⇒ REXML::Document?
Parses XML text and returns an
REXML::Document
object. -
.versions_from_content(content, regex = nil, &block) ⇒ Array<String>
Parses XML text and identifies versions using a
strategy
block.
Class Method Details
.element_text(element, child_path = nil) ⇒ String?
Retrieves the stripped inner text of an REXML
element. Returns
nil
if the optional child element doesn’t exist or the text is
blank.
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# File 'livecheck/strategy/xml.rb', line 89 def self.element_text(element, child_path = nil) element = element.get_elements(child_path).first if child_path.present? return if element.nil? text = element.text return if text.blank? text.strip end |
.find_versions(url:, regex: nil, provided_content: nil, homebrew_curl: false, **_unused, &block) ⇒ Hash{Symbol => T.untyped}
Checks the XML content at the URL for versions, using the provided
strategy
block to extract version information.
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# File 'livecheck/strategy/xml.rb', line 149 def self.find_versions(url:, regex: nil, provided_content: nil, homebrew_curl: false, **_unused, &block) raise ArgumentError, "#{Utils.demodulize(T.must(name))} requires a `strategy` block" if block.blank? match_data = { matches: {}, regex:, url: } return match_data if url.blank? || block.blank? content = if provided_content.is_a?(String) match_data[:cached] = true provided_content else match_data.merge!(Strategy.page_content(url, homebrew_curl:)) match_data[:content] end return match_data if content.blank? versions_from_content(content, regex, &block).each do |match_text| match_data[:matches][match_text] = Version.new(match_text) end match_data end |
.match?(url) ⇒ Boolean
Whether the strategy can be applied to the provided URL.
Homebrew::Livecheck::Strategy::Xml will technically match any HTTP URL but is only usable with
a livecheck
block containing a strategy
block.
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# File 'livecheck/strategy/xml.rb', line 47 def self.match?(url) URL_MATCH_REGEX.match?(url) end |
.parse_xml(content) ⇒ REXML::Document?
Parses XML text and returns an REXML::Document
object.
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# File 'livecheck/strategy/xml.rb', line 55 def self.parse_xml(content) parsing_tries = 0 begin REXML::Document.new(content) rescue REXML::UndefinedNamespaceException => e undefined_prefix = e.to_s[/Undefined prefix ([^ ]+) found/i, 1] raise "Could not identify undefined prefix." if undefined_prefix.blank? # Only retry parsing once after removing prefix from content parsing_tries += 1 raise "Could not parse XML after removing undefined prefix." if parsing_tries > 1 # When an XML document contains a prefix without a corresponding # namespace, it's necessary to remove the prefix from the content # to be able to successfully parse it using REXML content = content.gsub(%r{(</?| )#{Regexp.escape(undefined_prefix)}:}, '\1') retry end end |
.versions_from_content(content, regex = nil, &block) ⇒ Array<String>
Parses XML text and identifies versions using a strategy
block.
If a regex is provided, it will be passed as the second argument to
the strategy
block (after the parsed XML data).
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# File 'livecheck/strategy/xml.rb', line 113 def self.versions_from_content(content, regex = nil, &block) return [] if content.blank? || block.blank? require "rexml" xml = parse_xml(content) return [] if xml.blank? block_return_value = if regex.present? yield(xml, regex) elsif block.arity == 2 raise "Two arguments found in `strategy` block but no regex provided." else yield(xml) end Strategy.handle_block_return(block_return_value) end |