"xml.etree.ElementTree" — L'API ElementTree XML
***********************************************

**Code Source:** Lib/xml/etree/ElementTree.py

======================================================================

Le  module "xml.etree.ElementTree" implémente une API simple et
efficace pour analyser et créer des données XML.

Modifié dans la version 3.3: This module will use a fast
implementation whenever available. The "xml.etree.cElementTree" module
is deprecated.

Avertissement:

  The "xml.etree.ElementTree" module is not secure against maliciously
  constructed data.  If you need to parse untrusted or unauthenticated
  data see Vulnérabilités XML.


Tutoriel
========

Ceci est un petit tutoriel pour utiliser "xml.etree.ElementTree"
("ET").  Le but est de démontrer quelques composants et les concepts
basiques du module.


Arborescence et éléments XML
----------------------------

XML est un format de données fondamentalement hiérarchique et la façon
la plus naturelle de la représenter est avec un arbre. "ET" a deux
classes pour ce but- "ElementTree" représente l'ensemble du document
XML comme un arbre et "Element" est représenté en tant que nœud dans
cet arbre. Les interactions (lire et écrire vers/depuis des fichiers)
sur le document sont habituellement effectués au niveau de
"ElementTree". Les interactions sur un seul élément XML et ses sous-
éléments sont effectués au niveau de "Element".


Analyse XML
-----------

Nous utilisons le document XML suivant comme exemple pour cette
section :

   <?xml version="1.0"?>
   <data>
       <country name="Liechtenstein">
           <rank>1</rank>
           <year>2008</year>
           <gdppc>141100</gdppc>
           <neighbor name="Austria" direction="E"/>
           <neighbor name="Switzerland" direction="W"/>
       </country>
       <country name="Singapore">
           <rank>4</rank>
           <year>2011</year>
           <gdppc>59900</gdppc>
           <neighbor name="Malaysia" direction="N"/>
       </country>
       <country name="Panama">
           <rank>68</rank>
           <year>2011</year>
           <gdppc>13600</gdppc>
           <neighbor name="Costa Rica" direction="W"/>
           <neighbor name="Colombia" direction="E"/>
       </country>
   </data>

Nous pouvons importer cette donnée en lisant un fichier :

   import xml.etree.ElementTree as ET
   tree = ET.parse('country_data.xml')
   root = tree.getroot()

Ou depuis une chaîne de caractères :

   root = ET.fromstring(country_data_as_string)

"fromstring()" analyse le XML depuis une chaîne de caractères vers un
"Element", ce dernier est l'élément racine de l'arbre analysé.
D'Autres fonctions d'analyse peuvent créer un "ElementTree".  Vérifier
la documentation pour être sûr.

Comme "Element", "root" a une balise et un dictionnaire d'attributs :

   >>> root.tag
   'data'
   >>> root.attrib
   {}

Il contient aussi des nœuds enfants que nous pouvons itérer :

   >>> for child in root:
   ...     print(child.tag, child.attrib)
   ...
   country {'name': 'Liechtenstein'}
   country {'name': 'Singapore'}
   country {'name': 'Panama'}

Les enfants sont imbriqués et nous pouvons accéder aux nœuds enfants
spécifiques via un index :

   >>> root[0][1].text
   '2008'

Note:

  Les éléments du XML d'entrée ne sont pas tous considérés comme des
  éléments de l'arborescence. Souvent, le module ignore les
  commentaires XML, les instructions de traitements et la déclaration
  du type de document dans l'entrée. Néanmoins, les arborescences sont
  construites en utilisant l'API du module plutôt que d'analyser
  depuis un texte XML qui peut contenir des commentaires et des
  instructions de traitements ; ils peuvent être inclus lors de la
  génération du XML de sortie. Le type de déclaration du document est
  accessible en passant par une instance de "TreeBuilder" dans le
  constructeur de "XMLParser".


API à flux tiré
---------------

Most parsing functions provided by this module require the whole
document to be read at once before returning any result.  It is
possible to use an "XMLParser" and feed data into it incrementally,
but it is a push API that calls methods on a callback target, which is
too low-level and inconvenient for most needs.  Sometimes what the
user really wants is to be able to parse XML incrementally, without
blocking operations, while enjoying the convenience of fully
constructed "Element" objects.

The most powerful tool for doing this is "XMLPullParser".  It does not
require a blocking read to obtain the XML data, and is instead fed
with data incrementally with "XMLPullParser.feed()" calls.  To get the
parsed XML elements, call "XMLPullParser.read_events()".  Here is an
example:

   >>> parser = ET.XMLPullParser(['start', 'end'])
   >>> parser.feed('<mytag>sometext')
   >>> list(parser.read_events())
   [('start', <Element 'mytag' at 0x7fa66db2be58>)]
   >>> parser.feed(' more text</mytag>')
   >>> for event, elem in parser.read_events():
   ...     print(event)
   ...     print(elem.tag, 'text=', elem.text)
   ...
   end

The obvious use case is applications that operate in a non-blocking
fashion where the XML data is being received from a socket or read
incrementally from some storage device.  In such cases, blocking reads
are unacceptable.

Because it's so flexible, "XMLPullParser" can be inconvenient to use
for simpler use-cases.  If you don't mind your application blocking on
reading XML data but would still like to have incremental parsing
capabilities, take a look at "iterparse()".  It can be useful when
you're reading a large XML document and don't want to hold it wholly
in memory.

Where *immediate* feedback through events is wanted, calling method
"XMLPullParser.flush()" can help reduce delay; please make sure to
study the related security notes.


Trouver les éléments d'intérêt
------------------------------

"Element" a quelques méthodes très utiles qui aident à parcourir
récursivement tous les sous-arbres (ses enfants, leurs enfants et
ainsi de suite). Par exemple, "Element.iter()" :

   >>> for neighbor in root.iter('neighbor'):
   ...     print(neighbor.attrib)
   ...
   {'name': 'Austria', 'direction': 'E'}
   {'name': 'Switzerland', 'direction': 'W'}
   {'name': 'Malaysia', 'direction': 'N'}
   {'name': 'Costa Rica', 'direction': 'W'}
   {'name': 'Colombia', 'direction': 'E'}

"Element.findall()" récupère seulement les éléments avec une balise
qui sont les descendants directs de l'élément courant.
"Element.find()" récupère le *premier* élément avec une balise
particulière et "Element.text" accède au contenu textuel de l'élément.
"Element.get()" accède aux attributs de l'élément :

   >>> for country in root.findall('country'):
   ...     rank = country.find('rank').text
   ...     name = country.get('name')
   ...     print(name, rank)
   ...
   Liechtenstein 1
   Singapore 4
   Panama 68

More sophisticated specification of which elements to look for is
possible by using XPath.


Modification d'un fichier XML
-----------------------------

"ElementTree" provides a simple way to build XML documents and write
them to files. The "ElementTree.write()" method serves this purpose.

Once created, an "Element" object may be manipulated by directly
changing its fields (such as "Element.text"), adding and modifying
attributes ("Element.set()" method), as well as adding new children
(for example with "Element.append()").

Let's say we want to add one to each country's rank, and add an
"updated" attribute to the rank element:

   >>> for rank in root.iter('rank'):
   ...     new_rank = int(rank.text) + 1
   ...     rank.text = str(new_rank)
   ...     rank.set('updated', 'yes')
   ...
   >>> tree.write('output.xml')

Maintenant, notre XML ressemble à ceci :

   <?xml version="1.0"?>
   <data>
       <country name="Liechtenstein">
           <rank updated="yes">2</rank>
           <year>2008</year>
           <gdppc>141100</gdppc>
           <neighbor name="Austria" direction="E"/>
           <neighbor name="Switzerland" direction="W"/>
       </country>
       <country name="Singapore">
           <rank updated="yes">5</rank>
           <year>2011</year>
           <gdppc>59900</gdppc>
           <neighbor name="Malaysia" direction="N"/>
       </country>
       <country name="Panama">
           <rank updated="yes">69</rank>
           <year>2011</year>
           <gdppc>13600</gdppc>
           <neighbor name="Costa Rica" direction="W"/>
           <neighbor name="Colombia" direction="E"/>
       </country>
   </data>

We can remove elements using "Element.remove()".  Let's say we want to
remove all countries with a rank higher than 50:

   >>> for country in root.findall('country'):
   ...     # using root.findall() to avoid removal during traversal
   ...     rank = int(country.find('rank').text)
   ...     if rank > 50:
   ...         root.remove(country)
   ...
   >>> tree.write('output.xml')

Note that concurrent modification while iterating can lead to
problems, just like when iterating and modifying Python lists or
dicts. Therefore, the example first collects all matching elements
with "root.findall()", and only then iterates over the list of
matches.

Maintenant, notre XML ressemble à ceci :

   <?xml version="1.0"?>
   <data>
       <country name="Liechtenstein">
           <rank updated="yes">2</rank>
           <year>2008</year>
           <gdppc>141100</gdppc>
           <neighbor name="Austria" direction="E"/>
           <neighbor name="Switzerland" direction="W"/>
       </country>
       <country name="Singapore">
           <rank updated="yes">5</rank>
           <year>2011</year>
           <gdppc>59900</gdppc>
           <neighbor name="Malaysia" direction="N"/>
       </country>
   </data>


Création de documents XML
-------------------------

The "SubElement()" function also provides a convenient way to create
new sub-elements for a given element:

   >>> a = ET.Element('a')
   >>> b = ET.SubElement(a, 'b')
   >>> c = ET.SubElement(a, 'c')
   >>> d = ET.SubElement(c, 'd')
   >>> ET.dump(a)
   <a><b /><c><d /></c></a>


Analyse d'un XML avec des espaces de noms
-----------------------------------------

If the XML input has namespaces, tags and attributes with prefixes in
the form "prefix:sometag" get expanded to "{uri}sometag" where the
*prefix* is replaced by the full *URI*. Also, if there is a default
namespace, that full URI gets prepended to all of the non-prefixed
tags.

Here is an XML example that incorporates two namespaces, one with the
prefix "fictional" and the other serving as the default namespace:

   <?xml version="1.0"?>
   <actors xmlns:fictional="http://characters.example.com"
           xmlns="http://people.example.com">
       <actor>
           <name>John Cleese</name>
           <fictional:character>Lancelot</fictional:character>
           <fictional:character>Archie Leach</fictional:character>
       </actor>
       <actor>
           <name>Eric Idle</name>
           <fictional:character>Sir Robin</fictional:character>
           <fictional:character>Gunther</fictional:character>
           <fictional:character>Commander Clement</fictional:character>
       </actor>
   </actors>

One way to search and explore this XML example is to manually add the
URI to every tag or attribute in the xpath of a "find()" or
"findall()":

   root = fromstring(xml_text)
   for actor in root.findall('{http://people.example.com}actor'):
       name = actor.find('{http://people.example.com}name')
       print(name.text)
       for char in actor.findall('{http://characters.example.com}character'):
           print(' |-->', char.text)

A better way to search the namespaced XML example is to create a
dictionary with your own prefixes and use those in the search
functions:

   ns = {'real_person': 'http://people.example.com',
         'role': 'http://characters.example.com'}

   for actor in root.findall('real_person:actor', ns):
       name = actor.find('real_person:name', ns)
       print(name.text)
       for char in actor.findall('role:character', ns):
           print(' |-->', char.text)

Ces deux approches donnent le même résultat :

   John Cleese
    |--> Lancelot
    |--> Archie Leach
   Eric Idle
    |--> Sir Robin
    |--> Gunther
    |--> Commander Clement


Additional resources
--------------------

See http://effbot.org/zone/element-index.htm for tutorials and links
to other docs.


Prise en charge de XPath
========================

This module provides limited support for XPath expressions for
locating elements in a tree.  The goal is to support a small subset of
the abbreviated syntax; a full XPath engine is outside the scope of
the module.


Exemple
-------

Here's an example that demonstrates some of the XPath capabilities of
the module.  We'll be using the "countrydata" XML document from the
Parsing XML section:

   import xml.etree.ElementTree as ET

   root = ET.fromstring(countrydata)

   # Top-level elements
   root.findall(".")

   # All 'neighbor' grand-children of 'country' children of the top-level
   # elements
   root.findall("./country/neighbor")

   # Nodes with name='Singapore' that have a 'year' child
   root.findall(".//year/..[@name='Singapore']")

   # 'year' nodes that are children of nodes with name='Singapore'
   root.findall(".//*[@name='Singapore']/year")

   # All 'neighbor' nodes that are the second child of their parent
   root.findall(".//neighbor[2]")

For XML with namespaces, use the usual qualified "{namespace}tag"
notation:

   # All dublin-core "title" tags in the document
   root.findall(".//{http://purl.org/dc/elements/1.1/}title")


Prise en charge de la syntaxe XPath
-----------------------------------

+-------------------------+--------------------------------------------------------+
| Syntaxe                 | Signification                                          |
|=========================|========================================================|
| "tag"                   | Sélectionne tous les éléments enfants avec une balise  |
|                         | donnée. Par exemple, "spam" sélectionne tous les       |
|                         | éléments enfants nommés "spam" et "spam/egg"           |
|                         | sélectionne tous les petits-enfants nommés "egg" dans  |
|                         | les enfants nommés "spam". "{namespace}*" sélectionne  |
|                         | toutes les balises dans l'espace de nom donné,         |
|                         | "{*}spam" sélectionne les balises nommées "spam" dans  |
|                         | n'importe quel (ou aucun) espace de nom et "{}*"       |
|                         | sélectionne seulement les balises qui ne sont pas dans |
|                         | un espace de nom.  Modifié dans la version 3.8:        |
|                         | Support for star-wildcards was added.                  |
+-------------------------+--------------------------------------------------------+
| "*"                     | Selects all child elements, including comments and     |
|                         | processing instructions.  For example, "*/egg" selects |
|                         | all grandchildren named "egg".                         |
+-------------------------+--------------------------------------------------------+
| "."                     | Selects the current node.  This is mostly useful at    |
|                         | the beginning of the path, to indicate that it's a     |
|                         | relative path.                                         |
+-------------------------+--------------------------------------------------------+
| "//"                    | Selects all subelements, on all levels beneath the     |
|                         | current  element. For example, ".//egg" selects all    |
|                         | "egg" elements in the entire tree.                     |
+-------------------------+--------------------------------------------------------+
| ".."                    | Selects the parent element.  Returns "None" if the     |
|                         | path attempts to reach the ancestors of the start      |
|                         | element (the element "find" was called on).            |
+-------------------------+--------------------------------------------------------+
| "[@attrib]"             | Selects all elements that have the given attribute.    |
+-------------------------+--------------------------------------------------------+
| "[@attrib='value']"     | Selects all elements for which the given attribute has |
|                         | the given value.  The value cannot contain quotes.     |
+-------------------------+--------------------------------------------------------+
| "[tag]"                 | Selects all elements that have a child named "tag".    |
|                         | Only immediate children are supported.                 |
+-------------------------+--------------------------------------------------------+
| "[.='text']"            | Selects all elements whose complete text content,      |
|                         | including descendants, equals the given "text".        |
|                         | Nouveau dans la version 3.7.                           |
+-------------------------+--------------------------------------------------------+
| "[tag='text']"          | Selects all elements that have a child named "tag"     |
|                         | whose complete text content, including descendants,    |
|                         | equals the given "text".                               |
+-------------------------+--------------------------------------------------------+
| "[position]"            | Selects all elements that are located at the given     |
|                         | position.  The position can be either an integer (1 is |
|                         | the first position), the expression "last()" (for the  |
|                         | last position), or a position relative to the last     |
|                         | position (e.g. "last()-1").                            |
+-------------------------+--------------------------------------------------------+

Predicates (expressions within square brackets) must be preceded by a
tag name, an asterisk, or another predicate.  "position" predicates
must be preceded by a tag name.


Référence
=========


Fonctions
---------

xml.etree.ElementTree.canonicalize(xml_data=None, *, out=None, from_file=None, **options)

   C14N 2.0 fonction de transformation.

   Canonicalization is a way to normalise XML output in a way that
   allows byte-by-byte comparisons and digital signatures.  It reduced
   the freedom that XML serializers have and instead generates a more
   constrained XML representation.  The main restrictions regard the
   placement of namespace declarations, the ordering of attributes,
   and ignorable whitespace.

   This function takes an XML data string (*xml_data*) or a file path
   or file-like object (*from_file*) as input, converts it to the
   canonical form, and writes it out using the *out* file(-like)
   object, if provided, or returns it as a text string if not.  The
   output file receives text, not bytes.  It should therefore be
   opened in text mode with "utf-8" encoding.

   Typical uses:

      xml_data = "<root>...</root>"
      print(canonicalize(xml_data))

      with open("c14n_output.xml", mode='w', encoding='utf-8') as out_file:
          canonicalize(xml_data, out=out_file)

      with open("c14n_output.xml", mode='w', encoding='utf-8') as out_file:
          canonicalize(from_file="inputfile.xml", out=out_file)

   Les *options* de configuration sont les suivantes :

   * *with_comments* : attribue à vrai pour inclure les commentaires
     (par défaut : faux)

   * *strip_text*: set to true to strip whitespace before and after
     text content
        (par défaut : faux)

   * *rewrite_prefixes*: set to true to replace namespace prefixes by
     "n{number}"
        (par défaut : faux)

   * *qname_aware_tags*: a set of qname aware tag names in which
     prefixes
        should be replaced in text content (default: empty)

   * *qname_aware_attrs*: a set of qname aware attribute names in
     which prefixes
        should be replaced in text content (default: empty)

   * *exclude_attrs*: a set of attribute names that should not be
     serialised

   * *exclude_tags*: a set of tag names that should not be serialised

   In the option list above, "a set" refers to any collection or
   iterable of strings, no ordering is expected.

   Nouveau dans la version 3.8.

xml.etree.ElementTree.Comment(text=None)

   Comment element factory.  This factory function creates a special
   element that will be serialized as an XML comment by the standard
   serializer.  The comment string can be either a bytestring or a
   Unicode string.  *text* is a string containing the comment string.
   Returns an element instance representing a comment.

   Note that "XMLParser" skips over comments in the input instead of
   creating comment objects for them. An "ElementTree" will only
   contain comment nodes if they have been inserted into to the tree
   using one of the "Element" methods.

xml.etree.ElementTree.dump(elem)

   Writes an element tree or element structure to sys.stdout.  This
   function should be used for debugging only.

   The exact output format is implementation dependent.  In this
   version, it's written as an ordinary XML file.

   *elem* est un élément de l'arborescence ou un élément individuel.

   Modifié dans la version 3.8: The "dump()" function now preserves
   the attribute order specified by the user.

xml.etree.ElementTree.fromstring(text, parser=None)

   Parses an XML section from a string constant.  Same as "XML()".
   *text* is a string containing XML data.  *parser* is an optional
   parser instance. If not given, the standard "XMLParser" parser is
   used. Returns an "Element" instance.

xml.etree.ElementTree.fromstringlist(sequence, parser=None)

   Parses an XML document from a sequence of string fragments.
   *sequence* is a list or other sequence containing XML data
   fragments.  *parser* is an optional parser instance.  If not given,
   the standard "XMLParser" parser is used.  Returns an "Element"
   instance.

   Nouveau dans la version 3.2.

xml.etree.ElementTree.iselement(element)

   Check if an object appears to be a valid element object.  *element*
   is an element instance.  Return "True" if this is an element
   object.

xml.etree.ElementTree.iterparse(source, events=None, parser=None)

   Parses an XML section into an element tree incrementally, and
   reports what's going on to the user.  *source* is a filename or
   *file object* containing XML data.  *events* is a sequence of
   events to report back.  The supported events are the strings
   ""start"", ""end"", ""comment"", ""pi"", ""start-ns"" and ""end-
   ns"" (the "ns" events are used to get detailed namespace
   information).  If *events* is omitted, only ""end"" events are
   reported. *parser* is an optional parser instance.  If not given,
   the standard "XMLParser" parser is used.  *parser* must be a
   subclass of "XMLParser" and can only use the default "TreeBuilder"
   as a target.  Returns an *iterator* providing "(event, elem)"
   pairs.

   Note that while "iterparse()" builds the tree incrementally, it
   issues blocking reads on *source* (or the file it names).  As such,
   it's unsuitable for applications where blocking reads can't be
   made.  For fully non-blocking parsing, see "XMLPullParser".

   Note:

     "iterparse()" only guarantees that it has seen the ">" character
     of a starting tag when it emits a "start" event, so the
     attributes are defined, but the contents of the text and tail
     attributes are undefined at that point.  The same applies to the
     element children; they may or may not be present.If you need a
     fully populated element, look for "end" events instead.

   Obsolète depuis la version 3.4: L'argument *parser*.

   Modifié dans la version 3.8: Les évènements "comment" et "pi" ont
   été ajoutés.

xml.etree.ElementTree.parse(source, parser=None)

   Parses an XML section into an element tree.  *source* is a filename
   or file object containing XML data.  *parser* is an optional parser
   instance.  If not given, the standard "XMLParser" parser is used.
   Returns an "ElementTree" instance.

xml.etree.ElementTree.ProcessingInstruction(target, text=None)

   PI element factory.  This factory function creates a special
   element that will be serialized as an XML processing instruction.
   *target* is a string containing the PI target.  *text* is a string
   containing the PI contents, if given.  Returns an element instance,
   representing a processing instruction.

   Note that "XMLParser" skips over processing instructions in the
   input instead of creating comment objects for them. An
   "ElementTree" will only contain processing instruction nodes if
   they have been inserted into to the tree using one of the "Element"
   methods.

xml.etree.ElementTree.register_namespace(prefix, uri)

   Registers a namespace prefix.  The registry is global, and any
   existing mapping for either the given prefix or the namespace URI
   will be removed. *prefix* is a namespace prefix.  *uri* is a
   namespace uri.  Tags and attributes in this namespace will be
   serialized with the given prefix, if at all possible.

   Nouveau dans la version 3.2.

xml.etree.ElementTree.SubElement(parent, tag, attrib={}, **extra)

   Subelement factory.  This function creates an element instance, and
   appends it to an existing element.

   The element name, attribute names, and attribute values can be
   either bytestrings or Unicode strings.  *parent* is the parent
   element.  *tag* is the subelement name.  *attrib* is an optional
   dictionary, containing element attributes.  *extra* contains
   additional attributes, given as keyword arguments.  Returns an
   element instance.

xml.etree.ElementTree.tostring(element, encoding="us-ascii", method="xml", *, xml_declaration=None, default_namespace=None, short_empty_elements=True)

   Generates a string representation of an XML element, including all
   subelements.  *element* is an "Element" instance.  *encoding* [1]
   is the output encoding (default is US-ASCII).  Use
   "encoding="unicode"" to generate a Unicode string (otherwise, a
   bytestring is generated).  *method* is either ""xml"", ""html"" or
   ""text"" (default is ""xml""). *xml_declaration*,
   *default_namespace* and *short_empty_elements* has the same meaning
   as in "ElementTree.write()". Returns an (optionally) encoded string
   containing the XML data.

   Nouveau dans la version 3.4: Le paramètre *short_empty_elements*.

   Nouveau dans la version 3.8: Les paramètres *xml_declaration* et
   *default_namespace*.

   Modifié dans la version 3.8: The "tostring()" function now
   preserves the attribute order specified by the user.

xml.etree.ElementTree.tostringlist(element, encoding="us-ascii", method="xml", *, xml_declaration=None, default_namespace=None, short_empty_elements=True)

   Generates a string representation of an XML element, including all
   subelements.  *element* is an "Element" instance.  *encoding* [1]
   is the output encoding (default is US-ASCII).  Use
   "encoding="unicode"" to generate a Unicode string (otherwise, a
   bytestring is generated).  *method* is either ""xml"", ""html"" or
   ""text"" (default is ""xml""). *xml_declaration*,
   *default_namespace* and *short_empty_elements* has the same meaning
   as in "ElementTree.write()". Returns a list of (optionally) encoded
   strings containing the XML data. It does not guarantee any specific
   sequence, except that "b"".join(tostringlist(element)) ==
   tostring(element)".

   Nouveau dans la version 3.2.

   Nouveau dans la version 3.4: Le paramètre *short_empty_elements*.

   Nouveau dans la version 3.8: Les paramètres *xml_declaration* et
   *default_namespace*.

   Modifié dans la version 3.8: The "tostringlist()" function now
   preserves the attribute order specified by the user.

xml.etree.ElementTree.XML(text, parser=None)

   Parses an XML section from a string constant.  This function can be
   used to embed "XML literals" in Python code.  *text* is a string
   containing XML data.  *parser* is an optional parser instance.  If
   not given, the standard "XMLParser" parser is used.  Returns an
   "Element" instance.

xml.etree.ElementTree.XMLID(text, parser=None)

   Parses an XML section from a string constant, and also returns a
   dictionary which maps from element id:s to elements.  *text* is a
   string containing XML data.  *parser* is an optional parser
   instance.  If not given, the standard "XMLParser" parser is used.
   Returns a tuple containing an "Element" instance and a dictionary.


Prise en charge de XInclude
===========================

This module provides limited support for XInclude directives, via the
"xml.etree.ElementInclude" helper module.  This module can be used to
insert subtrees and text strings into element trees, based on
information in the tree.


Exemple
-------

Here's an example that demonstrates use of the XInclude module. To
include an XML document in the current document, use the
"{http://www.w3.org/2001/XInclude}include" element and set the
**parse** attribute to ""xml"", and use the **href** attribute to
specify the document to include.

   <?xml version="1.0"?>
   <document xmlns:xi="http://www.w3.org/2001/XInclude">
     <xi:include href="source.xml" parse="xml" />
   </document>

By default, the **href** attribute is treated as a file name. You can
use custom loaders to override this behaviour. Also note that the
standard helper does not support XPointer syntax.

To process this file, load it as usual, and pass the root element to
the "xml.etree.ElementTree" module:

   from xml.etree import ElementTree, ElementInclude

   tree = ElementTree.parse("document.xml")
   root = tree.getroot()

   ElementInclude.include(root)

The ElementInclude module replaces the
"{http://www.w3.org/2001/XInclude}include" element with the root
element from the **source.xml** document. The result might look
something like this:

   <document xmlns:xi="http://www.w3.org/2001/XInclude">
     <para>This is a paragraph.</para>
   </document>

If the **parse** attribute is omitted, it defaults to "xml". The href
attribute is required.

To include a text document, use the
"{http://www.w3.org/2001/XInclude}include" element, and set the
**parse** attribute to "text":

   <?xml version="1.0"?>
   <document xmlns:xi="http://www.w3.org/2001/XInclude">
     Copyright (c) <xi:include href="year.txt" parse="text" />.
   </document>

The result might look something like:

   <document xmlns:xi="http://www.w3.org/2001/XInclude">
     Copyright (c) 2003.
   </document>


Référence
=========


Fonctions
---------

xml.etree.ElementInclude.default_loader(href, parse, encoding=None)

   Default loader. This default loader reads an included resource from
   disk.  *href* is a URL. *parse* is for parse mode either "xml" or
   "text".  *encoding* is an optional text encoding.  If not given,
   encoding is "utf-8".  Returns the expanded resource.  If the parse
   mode is ""xml"", this is an ElementTree instance.  If the parse
   mode is "text", this is a Unicode string.  If the loader fails, it
   can return None or raise an exception.

xml.etree.ElementInclude.include(elem, loader=None)

   This function expands XInclude directives.  *elem* is the root
   element.  *loader* is an optional resource loader.  If omitted, it
   defaults to "default_loader()". If given, it should be a callable
   that implements the same interface as "default_loader()".  Returns
   the expanded resource.  If the parse mode is ""xml"", this is an
   ElementTree instance.  If the parse mode is "text", this is a
   Unicode string.  If the loader fails, it can return None or raise
   an exception.


Objets Elements
---------------

class xml.etree.ElementTree.Element(tag, attrib={}, **extra)

   Classe Element.  Cette classe définit l'interface Element et
   fournit une implémentation de référence de cette interface.

   The element name, attribute names, and attribute values can be
   either bytestrings or Unicode strings.  *tag* is the element name.
   *attrib* is an optional dictionary, containing element attributes.
   *extra* contains additional attributes, given as keyword arguments.

   tag

      A string identifying what kind of data this element represents
      (the element type, in other words).

   text
   tail

      These attributes can be used to hold additional data associated
      with the element.  Their values are usually strings but may be
      any application-specific object.  If the element is created from
      an XML file, the *text* attribute holds either the text between
      the element's start tag and its first child or end tag, or
      "None", and the *tail* attribute holds either the text between
      the element's end tag and the next tag, or "None".  For the XML
      data

         <a><b>1<c>2<d/>3</c></b>4</a>

      the *a* element has "None" for both *text* and *tail*
      attributes, the *b* element has *text* ""1"" and *tail* ""4"",
      the *c* element has *text* ""2"" and *tail* "None", and the *d*
      element has *text* "None" and *tail* ""3"".

      To collect the inner text of an element, see "itertext()", for
      example """.join(element.itertext())".

      Applications may store arbitrary objects in these attributes.

   attrib

      A dictionary containing the element's attributes.  Note that
      while the *attrib* value is always a real mutable Python
      dictionary, an ElementTree implementation may choose to use
      another internal representation, and create the dictionary only
      if someone asks for it.  To take advantage of such
      implementations, use the dictionary methods below whenever
      possible.

   Les méthodes dictionnaire-compatibles suivantes traitent les
   attributs de l'élément.

   clear()

      Resets an element.  This function removes all subelements,
      clears all attributes, and sets the text and tail attributes to
      "None".

   get(key, default=None)

      Accède à l'attribut de l'élément nommé *key*.

      Renvoie la valeur de l'attribut ou *default* si l'attribut n'a
      pas été trouvé.

   items()

      Renvoie les attributs de l'élément comme une séquence de paire
      (nom, valeur). Les attributs sont renvoyés un l'ordre
      arbitraire.

   keys()

      Returns the elements attribute names as a list.  The names are
      returned in an arbitrary order.

   set(key, value)

      Change l'attribut *key* à l'élément *value*.

   Les méthodes suivantes traitent les éléments enfants (sous-
   éléments).

   append(subelement)

      Adds the element *subelement* to the end of this element's
      internal list of subelements.  Raises "TypeError" if
      *subelement* is not an "Element".

   extend(subelements)

      Appends *subelements* from a sequence object with zero or more
      elements. Raises "TypeError" if a subelement is not an
      "Element".

      Nouveau dans la version 3.2.

   find(match, namespaces=None)

      Finds the first subelement matching *match*.  *match* may be a
      tag name or a path.  Returns an element instance or "None".
      *namespaces* is an optional mapping from namespace prefix to
      full name.  Pass "''" as prefix to move all unprefixed tag names
      in the expression into the given namespace.

   findall(match, namespaces=None)

      Finds all matching subelements, by tag name or path.  Returns a
      list containing all matching elements in document order.
      *namespaces* is an optional mapping from namespace prefix to
      full name.  Pass "''" as prefix to move all unprefixed tag names
      in the expression into the given namespace.

   findtext(match, default=None, namespaces=None)

      Finds text for the first subelement matching *match*.  *match*
      may be a tag name or a path.  Returns the text content of the
      first matching element, or *default* if no element was found.
      Note that if the matching element has no text content an empty
      string is returned. *namespaces* is an optional mapping from
      namespace prefix to full name.  Pass "''" as prefix to move all
      unprefixed tag names in the expression into the given namespace.

   getchildren()

      Deprecated since version 3.2, will be removed in version 3.9:
      Use "list(elem)" or iteration.

   getiterator(tag=None)

      Deprecated since version 3.2, will be removed in version 3.9:
      Use method "Element.iter()" instead.

   insert(index, subelement)

      Inserts *subelement* at the given position in this element.
      Raises "TypeError" if *subelement* is not an "Element".

   iter(tag=None)

      Creates a tree *iterator* with the current element as the root.
      The iterator iterates over this element and all elements below
      it, in document (depth first) order.  If *tag* is not "None" or
      "'*'", only elements whose tag equals *tag* are returned from
      the iterator.  If the tree structure is modified during
      iteration, the result is undefined.

      Nouveau dans la version 3.2.

   iterfind(match, namespaces=None)

      Finds all matching subelements, by tag name or path.  Returns an
      iterable yielding all matching elements in document order.
      *namespaces* is an optional mapping from namespace prefix to
      full name.

      Nouveau dans la version 3.2.

   itertext()

      Creates a text iterator.  The iterator loops over this element
      and all subelements, in document order, and returns all inner
      text.

      Nouveau dans la version 3.2.

   makeelement(tag, attrib)

      Creates a new element object of the same type as this element.
      Do not call this method, use the "SubElement()" factory function
      instead.

   remove(subelement)

      Removes *subelement* from the element.  Unlike the find* methods
      this method compares elements based on the instance identity,
      not on tag value or contents.

   "Element" objects also support the following sequence type methods
   for working with subelements: "__delitem__()", "__getitem__()",
   "__setitem__()", "__len__()".

   Caution: Elements with no subelements will test as "False".  This
   behavior will change in future versions.  Use specific "len(elem)"
   or "elem is None" test instead.

      element = root.find('foo')

      if not element:  # careful!
          print("element not found, or element has no subelements")

      if element is None:
          print("element not found")

   Prior to Python 3.8, the serialisation order of the XML attributes
   of elements was artificially made predictable by sorting the
   attributes by their name. Based on the now guaranteed ordering of
   dicts, this arbitrary reordering was removed in Python 3.8 to
   preserve the order in which attributes were originally parsed or
   created by user code.

   In general, user code should try not to depend on a specific
   ordering of attributes, given that the XML Information Set
   explicitly excludes the attribute order from conveying information.
   Code should be prepared to deal with any ordering on input. In
   cases where deterministic XML output is required, e.g. for
   cryptographic signing or test data sets, canonical serialisation is
   available with the "canonicalize()" function.

   In cases where canonical output is not applicable but a specific
   attribute order is still desirable on output, code should aim for
   creating the attributes directly in the desired order, to avoid
   perceptual mismatches for readers of the code. In cases where this
   is difficult to achieve, a recipe like the following can be applied
   prior to serialisation to enforce an order independently from the
   Element creation:

      def reorder_attributes(root):
          for el in root.iter():
              attrib = el.attrib
              if len(attrib) > 1:
                  # adjust attribute order, e.g. by sorting
                  attribs = sorted(attrib.items())
                  attrib.clear()
                  attrib.update(attribs)


Objets ElementTree
------------------

class xml.etree.ElementTree.ElementTree(element=None, file=None)

   ElementTree wrapper class.  This class represents an entire element
   hierarchy, and adds some extra support for serialization to and
   from standard XML.

   *element* is the root element.  The tree is initialized with the
   contents of the XML *file* if given.

   _setroot(element)

      Replaces the root element for this tree.  This discards the
      current contents of the tree, and replaces it with the given
      element.  Use with care.  *element* is an element instance.

   find(match, namespaces=None)

      Comme "Element.find()", commence à la racine de l'arbre.

   findall(match, namespaces=None)

      Same as "Element.findall()", starting at the root of the tree.

   findtext(match, default=None, namespaces=None)

      Same as "Element.findtext()", starting at the root of the tree.

   getiterator(tag=None)

      Deprecated since version 3.2, will be removed in version 3.9:
      Use method "ElementTree.iter()" instead.

   getroot()

      Renvoie l'élément racine de l'arbre.

   iter(tag=None)

      Creates and returns a tree iterator for the root element.  The
      iterator loops over all elements in this tree, in section order.
      *tag* is the tag to look for (default is to return all
      elements).

   iterfind(match, namespaces=None)

      Same as "Element.iterfind()", starting at the root of the tree.

      Nouveau dans la version 3.2.

   parse(source, parser=None)

      Loads an external XML section into this element tree.  *source*
      is a file name or *file object*.  *parser* is an optional parser
      instance. If not given, the standard "XMLParser" parser is used.
      Returns the section root element.

   write(file, encoding="us-ascii", xml_declaration=None, default_namespace=None, method="xml", *, short_empty_elements=True)

      Writes the element tree to a file, as XML.  *file* is a file
      name, or a *file object* opened for writing.  *encoding* [1] is
      the output encoding (default is US-ASCII). *xml_declaration*
      controls if an XML declaration should be added to the file.  Use
      "False" for never, "True" for always, "None" for only if not US-
      ASCII or UTF-8 or Unicode (default is "None").
      *default_namespace* sets the default XML namespace (for
      "xmlns"). *method* is either ""xml"", ""html"" or ""text""
      (default is ""xml""). The keyword-only *short_empty_elements*
      parameter controls the formatting of elements that contain no
      content.  If "True" (the default), they are emitted as a single
      self-closed tag, otherwise they are emitted as a pair of
      start/end tags.

      The output is either a string ("str") or binary ("bytes"). This
      is controlled by the *encoding* argument.  If *encoding* is
      ""unicode"", the output is a string; otherwise, it's binary.
      Note that this may conflict with the type of *file* if it's an
      open *file object*; make sure you do not try to write a string
      to a binary stream and vice versa.

      Nouveau dans la version 3.4: Le paramètre
      *short_empty_elements*.

      Modifié dans la version 3.8: The "write()" method now preserves
      the attribute order specified by the user.

This is the XML file that is going to be manipulated:

   <html>
       <head>
           <title>Example page</title>
       </head>
       <body>
           <p>Moved to <a href="http://example.org/">example.org</a>
           or <a href="http://example.com/">example.com</a>.</p>
       </body>
   </html>

Example of changing the attribute "target" of every link in first
paragraph:

   >>> from xml.etree.ElementTree import ElementTree
   >>> tree = ElementTree()
   >>> tree.parse("index.xhtml")
   <Element 'html' at 0xb77e6fac>
   >>> p = tree.find("body/p")     # Finds first occurrence of tag p in body
   >>> p
   <Element 'p' at 0xb77ec26c>
   >>> links = list(p.iter("a"))   # Returns list of all links
   >>> links
   [<Element 'a' at 0xb77ec2ac>, <Element 'a' at 0xb77ec1cc>]
   >>> for i in links:             # Iterates through all found links
   ...     i.attrib["target"] = "blank"
   >>> tree.write("output.xhtml")


Objets QName
------------

class xml.etree.ElementTree.QName(text_or_uri, tag=None)

   QName wrapper.  This can be used to wrap a QName attribute value,
   in order to get proper namespace handling on output.  *text_or_uri*
   is a string containing the QName value, in the form {uri}local, or,
   if the tag argument is given, the URI part of a QName.  If *tag* is
   given, the first argument is interpreted as a URI, and this
   argument is interpreted as a local name. "QName" instances are
   opaque.


Objets TreeBuilder
------------------

class xml.etree.ElementTree.TreeBuilder(element_factory=None, *, comment_factory=None, pi_factory=None, insert_comments=False, insert_pis=False)

   Generic element structure builder.  This builder converts a
   sequence of start, data, end, comment and pi method calls to a
   well-formed element structure.  You can use this class to build an
   element structure using a custom XML parser, or a parser for some
   other XML-like format.

   *element_factory*, when given, must be a callable accepting two
   positional arguments: a tag and a dict of attributes.  It is
   expected to return a new element instance.

   The *comment_factory* and *pi_factory* functions, when given,
   should behave like the "Comment()" and "ProcessingInstruction()"
   functions to create comments and processing instructions.  When not
   given, the default factories will be used.  When *insert_comments*
   and/or *insert_pis* is true, comments/pis will be inserted into the
   tree if they appear within the root element (but not outside of
   it).

   close()

      Flushes the builder buffers, and returns the toplevel document
      element.  Returns an "Element" instance.

   data(data)

      Ajoute du texte à l'élément courant.  *data* est une chaîne de
      caractères.  Cela peut être une chaîne d'octets ou une chaîne
      Unicode.

   end(tag)

      Ferme l'élément courant.  *tag* est le nom de l'élément.
      Renvoie l'élément fermé.

   start(tag, attrs)

      Opens a new element.  *tag* is the element name.  *attrs* is a
      dictionary containing element attributes.  Returns the opened
      element.

   comment(text)

      Creates a comment with the given *text*.  If "insert_comments"
      is true, this will also add it to the tree.

      Nouveau dans la version 3.8.

   pi(target, text)

      Creates a comment with the given *target* name and *text*.  If
      "insert_pis" is true, this will also add it to the tree.

      Nouveau dans la version 3.8.

   In addition, a custom "TreeBuilder" object can provide the
   following methods:

   doctype(name, pubid, system)

      Handles a doctype declaration.  *name* is the doctype name.
      *pubid* is the public identifier.  *system* is the system
      identifier.  This method does not exist on the default
      "TreeBuilder" class.

      Nouveau dans la version 3.2.

   start_ns(prefix, uri)

      Is called whenever the parser encounters a new namespace
      declaration, before the "start()" callback for the opening
      element that defines it. *prefix* is "''" for the default
      namespace and the declared namespace prefix name otherwise.
      *uri* is the namespace URI.

      Nouveau dans la version 3.8.

   end_ns(prefix)

      Is called after the "end()" callback of an element that declared
      a namespace prefix mapping, with the name of the *prefix* that
      went out of scope.

      Nouveau dans la version 3.8.

class xml.etree.ElementTree.C14NWriterTarget(write, *, with_comments=False, strip_text=False, rewrite_prefixes=False, qname_aware_tags=None, qname_aware_attrs=None, exclude_attrs=None, exclude_tags=None)

   A C14N 2.0 writer.  Arguments are the same as for the
   "canonicalize()" function.  This class does not build a tree but
   translates the callback events directly into a serialised form
   using the *write* function.

   Nouveau dans la version 3.8.


Objets XMLParser
----------------

class xml.etree.ElementTree.XMLParser(*, target=None, encoding=None)

   This class is the low-level building block of the module.  It uses
   "xml.parsers.expat" for efficient, event-based parsing of XML.  It
   can be fed XML data incrementally with the "feed()" method, and
   parsing events are translated to a push API - by invoking callbacks
   on the *target* object.  If *target* is omitted, the standard
   "TreeBuilder" is used. If *encoding* [1] is given, the value
   overrides the encoding specified in the XML file.

   Modifié dans la version 3.8: Parameters are now keyword-only. The
   *html* argument no longer supported.

   close()

      Finishes feeding data to the parser.  Returns the result of
      calling the "close()" method of the *target* passed during
      construction; by default, this is the toplevel document element.

   feed(data)

      Feeds data to the parser.  *data* is encoded data.

   flush()

      Triggers parsing of any previously fed unparsed data, which can
      be used to ensure more immediate feedback, in particular with
      Expat >=2.6.0. The implementation of "flush()" temporarily
      disables reparse deferral with Expat (if currently enabled) and
      triggers a reparse. Disabling reparse deferral has security
      consequences; please see
      "xml.parsers.expat.xmlparser.SetReparseDeferralEnabled()" for
      details.

      Note that "flush()" has been backported to some prior releases
      of CPython as a security fix.  Check for availability of
      "flush()" using "hasattr()" if used in code running across a
      variety of Python versions.

      Nouveau dans la version 3.8.19.

   "XMLParser.feed()" calls *target*'s "start(tag, attrs_dict)" method
   for each opening tag, its "end(tag)" method for each closing tag,
   and data is processed by method "data(data)".  For further
   supported callback methods, see the "TreeBuilder" class.
   "XMLParser.close()" calls *target*'s method "close()". "XMLParser"
   can be used not only for building a tree structure. This is an
   example of counting the maximum depth of an XML file:

      >>> from xml.etree.ElementTree import XMLParser
      >>> class MaxDepth:                     # The target object of the parser
      ...     maxDepth = 0
      ...     depth = 0
      ...     def start(self, tag, attrib):   # Called for each opening tag.
      ...         self.depth += 1
      ...         if self.depth > self.maxDepth:
      ...             self.maxDepth = self.depth
      ...     def end(self, tag):             # Called for each closing tag.
      ...         self.depth -= 1
      ...     def data(self, data):
      ...         pass            # We do not need to do anything with data.
      ...     def close(self):    # Called when all data has been parsed.
      ...         return self.maxDepth
      ...
      >>> target = MaxDepth()
      >>> parser = XMLParser(target=target)
      >>> exampleXml = """
      ... <a>
      ...   <b>
      ...   </b>
      ...   <b>
      ...     <c>
      ...       <d>
      ...       </d>
      ...     </c>
      ...   </b>
      ... </a>"""
      >>> parser.feed(exampleXml)
      >>> parser.close()
      4


Objets XMLPullParser
--------------------

class xml.etree.ElementTree.XMLPullParser(events=None)

   A pull parser suitable for non-blocking applications.  Its input-
   side API is similar to that of "XMLParser", but instead of pushing
   calls to a callback target, "XMLPullParser" collects an internal
   list of parsing events and lets the user read from it. *events* is
   a sequence of events to report back.  The supported events are the
   strings ""start"", ""end"", ""comment"", ""pi"", ""start-ns"" and
   ""end-ns"" (the "ns" events are used to get detailed namespace
   information).  If *events* is omitted, only ""end"" events are
   reported.

   feed(data)

      Feed the given bytes data to the parser.

   flush()

      Triggers parsing of any previously fed unparsed data, which can
      be used to ensure more immediate feedback, in particular with
      Expat >=2.6.0. The implementation of "flush()" temporarily
      disables reparse deferral with Expat (if currently enabled) and
      triggers a reparse. Disabling reparse deferral has security
      consequences; please see
      "xml.parsers.expat.xmlparser.SetReparseDeferralEnabled()" for
      details.

      Note that "flush()" has been backported to some prior releases
      of CPython as a security fix.  Check for availability of
      "flush()" using "hasattr()" if used in code running across a
      variety of Python versions.

      Nouveau dans la version 3.8.19.

   close()

      Signal the parser that the data stream is terminated. Unlike
      "XMLParser.close()", this method always returns "None". Any
      events not yet retrieved when the parser is closed can still be
      read with "read_events()".

   read_events()

      Return an iterator over the events which have been encountered
      in the data fed to the parser.  The iterator yields "(event,
      elem)" pairs, where *event* is a string representing the type of
      event (e.g. ""end"") and *elem* is the encountered "Element"
      object, or other context value as follows.

      * "start", "end": the current Element.

      * "comment", "pi": the current comment / processing instruction

      * "start-ns": a tuple "(prefix, uri)" naming the declared
        namespace mapping.

      * "end-ns": "None" (this may change in a future version)

      Events provided in a previous call to "read_events()" will not
      be yielded again.  Events are consumed from the internal queue
      only when they are retrieved from the iterator, so multiple
      readers iterating in parallel over iterators obtained from
      "read_events()" will have unpredictable results.

   Note:

     "XMLPullParser" only guarantees that it has seen the ">"
     character of a starting tag when it emits a "start" event, so the
     attributes are defined, but the contents of the text and tail
     attributes are undefined at that point.  The same applies to the
     element children; they may or may not be present.If you need a
     fully populated element, look for "end" events instead.

   Nouveau dans la version 3.4.

   Modifié dans la version 3.8: Les évènements "comment" et "pi" ont
   été ajoutés.


Exceptions
----------

class xml.etree.ElementTree.ParseError

   XML parse error, raised by the various parsing methods in this
   module when parsing fails.  The string representation of an
   instance of this exception will contain a user-friendly error
   message.  In addition, it will have the following attributes
   available:

   code

      A numeric error code from the expat parser. See the
      documentation of "xml.parsers.expat" for the list of error codes
      and their meanings.

   position

      Un *n*-uplet de numéro de *ligne*, de *colonne* indiquant le
      lieu d'apparition de l'erreur.

-[ Notes ]-

[1] La chaîne de caractères encodée inclue dans la sortie XML doit
    être conforme aux standards. Par exemple, « UTF-8 » est valide,
    mais pas « UTF8 ».  Voir https://www.w3.org/TR/2006/REC-
    xml11-20060816/#NT-EncodingDecl et
    https://www.iana.org/assignments/character-sets/character-
    sets.xhtml.
