Working with XML

Encode and decode to and from XML. Whitespace is not conserved for round trips - but the order of the fields are.
Consecutive xml nodes with the same name are assumed to be arrays.
XML content data, attributes processing instructions and directives are all created as plain fields.
This can be controlled by:
Flag
Default
Sample XML
--xml-attribute-prefix
+ (changing to [email protected] soon)
Legs in <cat legs="4"/>
--xml-content-name
+content
Meow in <cat>Meow <fur>true</true></cat>
--xml-directive-name
+directive
<!DOCTYPE config system "blah">
--xml-proc-inst-prefix
+p_
<?xml version="1"?>
Default Attribute Prefix will be changing in v4.30! In order to avoid name conflicts (e.g. having an attribute named "content" will create a field that clashes with the default content name of "+content") the attribute prefix will be changing to "[email protected]".
This will affect users that have not set their own prefix and are not roundtripping XML changes.
Encoder / Decoder flag options
In addition to the above flags, there are the following xml encoder/decoder options controlled by flags:
Flag
Default
Description
--xml-strict-mode
false
Strict mode enforces the requirements of the XML specification. When switched off the parser allows input containing common mistakes. See the Golang xml decoder for more details.
--xml-keep-namespace
true
Keeps the namespace of attributes
--xml-raw-token
true
Does not verify that start and end elements match and does not translate name space prefixes to their corresponding URLs.
--xml-skip-proc-inst
false
Skips over processing instructions, e.g. <?xml version="1"?>
--xml-skip-directives
false
Skips over directives, e.g. <!DOCTYPE config system "blah">
See below for examples
Parse xml: simple
Notice how all the values are strings, see the next example on how you can fix that.
Given a sample.xml file of:
<?xml version="1.0" encoding="UTF-8"?>
<cat>
  <says>meow</says>
  <legs>4</legs>
  <cute>true</cute>
</cat>
then
yq -p=xml '.' sample.xml
will output
+p_xml: version="1.0" encoding="UTF-8"
cat:
  says: meow
  legs: "4"
  cute: "true"
Parse xml: number
All values are assumed to be strings when parsing XML, but you can use the from_yaml operator on all the strings values to autoparse into the correct type.
Given a sample.xml file of:
<?xml version="1.0" encoding="UTF-8"?>
<cat>
  <says>meow</says>
  <legs>4</legs>
  <cute>true</cute>
</cat>
then
yq -p=xml ' (.. | select(tag == "!!str")) |= from_yaml' sample.xml
will output
+p_xml: version="1.0" encoding="UTF-8"
cat:
  says: meow
  legs: 4
  cute: true
Parse xml: array
Consecutive nodes with identical xml names are assumed to be arrays.
Given a sample.xml file of:
<?xml version="1.0" encoding="UTF-8"?>
<animal>cat</animal>
<animal>goat</animal>
then
yq -p=xml '.' sample.xml
will output
+p_xml: version="1.0" encoding="UTF-8"
animal:
  - cat
  - goat
Parse xml: attributes
Attributes are converted to fields, with the default attribute prefix '+'. Use '--xml-attribute-prefix` to set your own.
Given a sample.xml file of:
<?xml version="1.0" encoding="UTF-8"?>
<cat legs="4">
  <legs>7</legs>
</cat>
then
yq -p=xml '.' sample.xml
will output
+p_xml: version="1.0" encoding="UTF-8"
cat:
  [email protected]: "4"
  legs: "7"
Parse xml: attributes with content
Content is added as a field, using the default content name of +content. Use --xml-content-name to set your own.
Given a sample.xml file of:
<?xml version="1.0" encoding="UTF-8"?>
<cat legs="4">meow</cat>
then
yq -p=xml '.' sample.xml
will output
+p_xml: version="1.0" encoding="UTF-8"
cat:
  +content: meow
  [email protected]: "4"
Parse xml: custom dtd
DTD entities are processed as directives.
Given a sample.xml file of:
<?xml version="1.0"?>
<!DOCTYPE root [
<!ENTITY writer "Blah.">
<!ENTITY copyright "Blah">
]>
<root>
    <item>&writer;&copyright;</item>
</root>
then
yq -p=xml -o=xml '.' sample.xml
will output
<?xml version="1.0"?>
<!DOCTYPE root [
<!ENTITY writer "Blah.">
<!ENTITY copyright "Blah">
]>
<root>
  <item>&amp;writer;&amp;copyright;</item>
</root>
Parse xml: skip custom dtd
DTDs are directives, skip over directives to skip DTDs.
Given a sample.xml file of:
<?xml version="1.0"?>
<!DOCTYPE root [
<!ENTITY writer "Blah.">
<!ENTITY copyright "Blah">
]>
<root>
    <item>&writer;&copyright;</item>
</root>
then
yq -p=xml -o=xml --xml-skip-directives '.' sample.xml
will output
<?xml version="1.0"?>
<root>
  <item>&amp;writer;&amp;copyright;</item>
</root>
Parse xml: with comments
A best attempt is made to preserve comments.
Given a sample.xml file of:
<!-- before cat -->
<cat>
	<!-- in cat before -->
	<x>3<!-- multi
line comment 
for x --></x>
	<!-- before y -->
	<y>
		<!-- in y before -->
		<d><!-- in d before -->z<!-- in d after --></d>
		
		<!-- in y after -->
	</y>
	<!-- in_cat_after -->
</cat>
<!-- after cat -->
then
yq -p=xml '.' sample.xml
will output
# before cat
cat:
  # in cat before
  x: "3" # multi
  # line comment 
  # for x
  # before y
​
  y:
    # in y before
    # in d before
    d: z # in d after
    # in y after
  # in_cat_after
# after cat
Parse xml: keep attribute namespace
Defaults to true
Given a sample.xml file of:
<?xml version="1.0"?>
<map xmlns="some-namespace" xmlns:xsi="some-instance" xsi:schemaLocation="some-url"></map>
then
yq -p=xml -o=xml --xml-keep-namespace=false '.' sample.xml
will output
<?xml version="1.0"?>
<map xmlns="some-namespace" xsi="some-instance" schemaLocation="some-url"></map>
instead of
<?xml version="1.0"?>
<map xmlns="some-namespace" xmlns:xsi="some-instance" xsi:schemaLocation="some-url"></map>
Parse xml: keep raw attribute namespace
Defaults to true
Given a sample.xml file of:
<?xml version="1.0"?>
<map xmlns="some-namespace" xmlns:xsi="some-instance" xsi:schemaLocation="some-url"></map>
then
yq -p=xml -o=xml --xml-raw-token=false '.' sample.xml
will output
<?xml version="1.0"?>
<map xmlns="some-namespace" xmlns:xsi="some-instance" some-instance:schemaLocation="some-url"></map>
instead of
<?xml version="1.0"?>
<map xmlns="some-namespace" xmlns:xsi="some-instance" xsi:schemaLocation="some-url"></map>
Encode xml: simple
Given a sample.yml file of:
cat: purrs
then
yq -o=xml '.' sample.yml
will output
<cat>purrs</cat>
Encode xml: array
Given a sample.yml file of:
pets:
  cat:
    - purrs
    - meows
then
yq -o=xml '.' sample.yml
will output
<pets>
  <cat>purrs</cat>
  <cat>meows</cat>
</pets>
Encode xml: attributes
Fields with the matching xml-attribute-prefix are assumed to be attributes.
Given a sample.yml file of:
cat:
  [email protected]: tiger
  meows: true
then
yq -o=xml '.' sample.yml
will output
<cat name="tiger">
  <meows>true</meows>
</cat>
Encode xml: attributes with content
Fields with the matching xml-content-name is assumed to be content.
Given a sample.yml file of:
cat:
  [email protected]: tiger
  +content: cool
then
yq -o=xml '.' sample.yml
will output
<cat name="tiger">cool</cat>
Encode xml: comments
A best attempt is made to copy comments to xml.
Given a sample.yml file of:
# header comment
# above_cat
cat: # inline_cat
  # above_array
  array: # inline_array
    - val1 # inline_val1
    # above_val2
    - val2 # inline_val2
# below_cat
then
yq -o=xml '.' sample.yml
will output
<!--
 header comment
 above_cat
 --><!-- inline_cat --><cat><!-- above_array inline_array -->
  <array>val1<!-- inline_val1 --></array>
  <array><!-- above_val2 -->val2<!-- inline_val2 --></array>
</cat><!-- below_cat -->
Encode: doctype and xml declaration
Use the special xml names to add/modify proc instructions and directives.
Given a sample.yml file of:
+p_xml: version="1.0"
+directive: 'DOCTYPE config SYSTEM "/etc/iwatch/iwatch.dtd" '
apple:
  +p_coolioo: version="1.0"
  +directive: 'CATYPE meow purr puss '
  b: things
then
yq -o=xml '.' sample.yml
will output
<?xml version="1.0"?>
<!DOCTYPE config SYSTEM "/etc/iwatch/iwatch.dtd" >
<apple><?coolioo version="1.0"?><!CATYPE meow purr puss >
  <b>things</b>
</apple>
Round trip: with comments
A best effort is made, but comment positions and white space are not preserved perfectly.
Given a sample.xml file of:
<!-- before cat -->
<cat>
	<!-- in cat before -->
	<x>3<!-- multi
line comment 
for x --></x>
	<!-- before y -->
	<y>
		<!-- in y before -->
		<d><!-- in d before -->z<!-- in d after --></d>
		
		<!-- in y after -->
	</y>
	<!-- in_cat_after -->
</cat>
<!-- after cat -->
then
yq -p=xml -o=xml '.' sample.xml
will output
<!-- before cat --><cat><!-- in cat before -->
  <x>3<!-- multi
line comment 
for x --></x><!-- before y -->
  <y><!-- in y before
in d before -->
    <d>z<!-- in d after --></d><!-- in y after -->
  </y><!-- in_cat_after -->
</cat><!-- after cat -->
Roundtrip: with doctype and declaration
yq parses XML proc instructions and directives into nodes. Unfortunately the underlying XML parser loses whitespace information.
Given a sample.xml file of:
<?xml version="1.0"?>
<!DOCTYPE config SYSTEM "/etc/iwatch/iwatch.dtd" >
<apple>
  <?coolioo version="1.0"?>
  <!CATYPE meow purr puss >
  <b>things</b>
</apple>
then
yq -p=xml -o=xml '.' sample.xml
will output
<?xml version="1.0"?>
<!DOCTYPE config SYSTEM "/etc/iwatch/iwatch.dtd" >
<apple><?coolioo version="1.0"?><!CATYPE meow purr puss >
  <b>things</b>
</apple>
Flag	Default	Sample XML
`--xml-attribute-prefix`	`+` (changing to `[email protected]` soon)	Legs in `<cat legs="4"/>`
`--xml-content-name`	`+content`	Meow in `<cat>Meow <fur>true</true></cat>`
`--xml-directive-name`	`+directive`	`<!DOCTYPE config system "blah">`
`--xml-proc-inst-prefix`	`+p_`	`<?xml version="1"?>`
Flag	Default	Description
`--xml-strict-mode`	false	Strict mode enforces the requirements of the XML specification. When switched off the parser allows input containing common mistakes. See the Golang xml decoder for more details.
`--xml-keep-namespace`	true	Keeps the namespace of attributes
`--xml-raw-token`	true	Does not verify that start and end elements match and does not translate name space prefixes to their corresponding URLs.
`--xml-skip-proc-inst`	false	Skips over processing instructions, e.g. `<?xml version="1"?>`
`--xml-skip-directives`	false	Skips over directives, e.g. `<!DOCTYPE config system "blah">`
Last modified 16d ago