Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1 | :mod:`xml.etree.ElementTree` --- The ElementTree XML API |
| 2 | ======================================================== |
| 3 | |
| 4 | .. module:: xml.etree.ElementTree |
| 5 | :synopsis: Implementation of the ElementTree API. |
| 6 | .. moduleauthor:: Fredrik Lundh <fredrik@pythonware.com> |
| 7 | |
| 8 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 9 | The Element type is a flexible container object, designed to store hierarchical |
| 10 | data structures in memory. The type can be described as a cross between a list |
| 11 | and a dictionary. |
| 12 | |
| 13 | Each element has a number of properties associated with it: |
| 14 | |
| 15 | * a tag which is a string identifying what kind of data this element represents |
| 16 | (the element type, in other words). |
| 17 | |
| 18 | * a number of attributes, stored in a Python dictionary. |
| 19 | |
| 20 | * a text string. |
| 21 | |
| 22 | * an optional tail string. |
| 23 | |
| 24 | * a number of child elements, stored in a Python sequence |
| 25 | |
| 26 | To create an element instance, use the Element or SubElement factory functions. |
| 27 | |
| 28 | The :class:`ElementTree` class can be used to wrap an element structure, and |
| 29 | convert it from and to XML. |
| 30 | |
| 31 | A C implementation of this API is available as :mod:`xml.etree.cElementTree`. |
| 32 | |
Christian Heimes | d8654cf | 2007-12-02 15:22:16 +0000 | [diff] [blame] | 33 | See http://effbot.org/zone/element-index.htm for tutorials and links to other |
Georg Brandl | 48310cd | 2009-01-03 21:18:54 +0000 | [diff] [blame] | 34 | docs. Fredrik Lundh's page is also the location of the development version of the |
Christian Heimes | d8654cf | 2007-12-02 15:22:16 +0000 | [diff] [blame] | 35 | xml.etree.ElementTree. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 36 | |
| 37 | .. _elementtree-functions: |
| 38 | |
| 39 | Functions |
| 40 | --------- |
| 41 | |
| 42 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 43 | .. function:: Comment(text=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 44 | |
Georg Brandl | f694518 | 2008-02-01 11:56:49 +0000 | [diff] [blame] | 45 | Comment element factory. This factory function creates a special element |
| 46 | that will be serialized as an XML comment. The comment string can be either |
| 47 | an ASCII-only :class:`bytes` object or a :class:`str` object. *text* is a |
| 48 | string containing the comment string. Returns an element instance |
| 49 | representing a comment. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 50 | |
| 51 | |
| 52 | .. function:: dump(elem) |
| 53 | |
| 54 | Writes an element tree or element structure to sys.stdout. This function should |
| 55 | be used for debugging only. |
| 56 | |
| 57 | The exact output format is implementation dependent. In this version, it's |
| 58 | written as an ordinary XML file. |
| 59 | |
| 60 | *elem* is an element tree or an individual element. |
| 61 | |
| 62 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 63 | .. function:: Element(tag, attrib={}, **extra) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 64 | |
| 65 | Element factory. This function returns an object implementing the standard |
| 66 | Element interface. The exact class or type of that object is implementation |
| 67 | dependent, but it will always be compatible with the _ElementInterface class in |
| 68 | this module. |
| 69 | |
Georg Brandl | f694518 | 2008-02-01 11:56:49 +0000 | [diff] [blame] | 70 | The element name, attribute names, and attribute values can be either an |
| 71 | ASCII-only :class:`bytes` object or a :class:`str` object. *tag* is the |
| 72 | element name. *attrib* is an optional dictionary, containing element |
| 73 | attributes. *extra* contains additional attributes, given as keyword |
| 74 | arguments. Returns an element instance. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 75 | |
| 76 | |
| 77 | .. function:: fromstring(text) |
| 78 | |
| 79 | Parses an XML section from a string constant. Same as XML. *text* is a string |
| 80 | containing XML data. Returns an Element instance. |
| 81 | |
| 82 | |
| 83 | .. function:: iselement(element) |
| 84 | |
| 85 | Checks if an object appears to be a valid element object. *element* is an |
| 86 | element instance. Returns a true value if this is an element object. |
| 87 | |
| 88 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 89 | .. function:: iterparse(source, events=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 90 | |
| 91 | Parses an XML section into an element tree incrementally, and reports what's |
| 92 | going on to the user. *source* is a filename or file object containing XML data. |
| 93 | *events* is a list of events to report back. If omitted, only "end" events are |
Georg Brandl | 9afde1c | 2007-11-01 20:32:30 +0000 | [diff] [blame] | 94 | reported. Returns an :term:`iterator` providing ``(event, elem)`` pairs. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 95 | |
Benjamin Peterson | 75edad0 | 2009-01-01 15:05:06 +0000 | [diff] [blame] | 96 | .. note:: |
| 97 | |
| 98 | :func:`iterparse` only guarantees that it has seen the ">" |
| 99 | character of a starting tag when it emits a "start" event, so the |
| 100 | attributes are defined, but the contents of the text and tail attributes |
| 101 | are undefined at that point. The same applies to the element children; |
| 102 | they may or may not be present. |
| 103 | |
| 104 | If you need a fully populated element, look for "end" events instead. |
| 105 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 106 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 107 | .. function:: parse(source, parser=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 108 | |
| 109 | Parses an XML section into an element tree. *source* is a filename or file |
| 110 | object containing XML data. *parser* is an optional parser instance. If not |
| 111 | given, the standard XMLTreeBuilder parser is used. Returns an ElementTree |
| 112 | instance. |
| 113 | |
| 114 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 115 | .. function:: ProcessingInstruction(target, text=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 116 | |
| 117 | PI element factory. This factory function creates a special element that will |
| 118 | be serialized as an XML processing instruction. *target* is a string containing |
| 119 | the PI target. *text* is a string containing the PI contents, if given. Returns |
| 120 | an element instance, representing a processing instruction. |
| 121 | |
| 122 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 123 | .. function:: SubElement(parent, tag, attrib={}, **extra) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 124 | |
| 125 | Subelement factory. This function creates an element instance, and appends it |
| 126 | to an existing element. |
| 127 | |
Georg Brandl | f694518 | 2008-02-01 11:56:49 +0000 | [diff] [blame] | 128 | The element name, attribute names, and attribute values can be an ASCII-only |
| 129 | :class:`bytes` object or a :class:`str` object. *parent* is the parent |
| 130 | element. *tag* is the subelement name. *attrib* is an optional dictionary, |
| 131 | containing element attributes. *extra* contains additional attributes, given |
| 132 | as keyword arguments. Returns an element instance. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 133 | |
| 134 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 135 | .. function:: tostring(element, encoding=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 136 | |
| 137 | Generates a string representation of an XML element, including all subelements. |
| 138 | *element* is an Element instance. *encoding* is the output encoding (default is |
| 139 | US-ASCII). Returns an encoded string containing the XML data. |
| 140 | |
| 141 | |
| 142 | .. function:: XML(text) |
| 143 | |
| 144 | Parses an XML section from a string constant. This function can be used to |
| 145 | embed "XML literals" in Python code. *text* is a string containing XML data. |
| 146 | Returns an Element instance. |
| 147 | |
| 148 | |
| 149 | .. function:: XMLID(text) |
| 150 | |
| 151 | Parses an XML section from a string constant, and also returns a dictionary |
| 152 | which maps from element id:s to elements. *text* is a string containing XML |
| 153 | data. Returns a tuple containing an Element instance and a dictionary. |
| 154 | |
| 155 | |
| 156 | .. _elementtree-element-interface: |
| 157 | |
| 158 | The Element Interface |
| 159 | --------------------- |
| 160 | |
| 161 | Element objects returned by Element or SubElement have the following methods |
| 162 | and attributes. |
| 163 | |
| 164 | |
| 165 | .. attribute:: Element.tag |
| 166 | |
| 167 | A string identifying what kind of data this element represents (the element |
| 168 | type, in other words). |
| 169 | |
| 170 | |
| 171 | .. attribute:: Element.text |
| 172 | |
| 173 | The *text* attribute can be used to hold additional data associated with the |
| 174 | element. As the name implies this attribute is usually a string but may be any |
| 175 | application-specific object. If the element is created from an XML file the |
| 176 | attribute will contain any text found between the element tags. |
| 177 | |
| 178 | |
| 179 | .. attribute:: Element.tail |
| 180 | |
| 181 | The *tail* attribute can be used to hold additional data associated with the |
| 182 | element. This attribute is usually a string but may be any application-specific |
| 183 | object. If the element is created from an XML file the attribute will contain |
| 184 | any text found after the element's end tag and before the next tag. |
| 185 | |
| 186 | |
| 187 | .. attribute:: Element.attrib |
| 188 | |
| 189 | A dictionary containing the element's attributes. Note that while the *attrib* |
| 190 | value is always a real mutable Python dictionary, an ElementTree implementation |
| 191 | may choose to use another internal representation, and create the dictionary |
| 192 | only if someone asks for it. To take advantage of such implementations, use the |
| 193 | dictionary methods below whenever possible. |
| 194 | |
| 195 | The following dictionary-like methods work on the element attributes. |
| 196 | |
| 197 | |
| 198 | .. method:: Element.clear() |
| 199 | |
| 200 | Resets an element. This function removes all subelements, clears all |
| 201 | attributes, and sets the text and tail attributes to None. |
| 202 | |
| 203 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 204 | .. method:: Element.get(key, default=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 205 | |
| 206 | Gets the element attribute named *key*. |
| 207 | |
| 208 | Returns the attribute value, or *default* if the attribute was not found. |
| 209 | |
| 210 | |
| 211 | .. method:: Element.items() |
| 212 | |
| 213 | Returns the element attributes as a sequence of (name, value) pairs. The |
| 214 | attributes are returned in an arbitrary order. |
| 215 | |
| 216 | |
| 217 | .. method:: Element.keys() |
| 218 | |
| 219 | Returns the elements attribute names as a list. The names are returned in an |
| 220 | arbitrary order. |
| 221 | |
| 222 | |
| 223 | .. method:: Element.set(key, value) |
| 224 | |
| 225 | Set the attribute *key* on the element to *value*. |
| 226 | |
| 227 | The following methods work on the element's children (subelements). |
| 228 | |
| 229 | |
| 230 | .. method:: Element.append(subelement) |
| 231 | |
| 232 | Adds the element *subelement* to the end of this elements internal list of |
| 233 | subelements. |
| 234 | |
| 235 | |
| 236 | .. method:: Element.find(match) |
| 237 | |
| 238 | Finds the first subelement matching *match*. *match* may be a tag name or path. |
| 239 | Returns an element instance or ``None``. |
| 240 | |
| 241 | |
| 242 | .. method:: Element.findall(match) |
| 243 | |
| 244 | Finds all subelements matching *match*. *match* may be a tag name or path. |
| 245 | Returns an iterable yielding all matching elements in document order. |
| 246 | |
| 247 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 248 | .. method:: Element.findtext(condition, default=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 249 | |
| 250 | Finds text for the first subelement matching *condition*. *condition* may be a |
| 251 | tag name or path. Returns the text content of the first matching element, or |
| 252 | *default* if no element was found. Note that if the matching element has no |
| 253 | text content an empty string is returned. |
| 254 | |
| 255 | |
| 256 | .. method:: Element.getchildren() |
| 257 | |
| 258 | Returns all subelements. The elements are returned in document order. |
| 259 | |
| 260 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 261 | .. method:: Element.getiterator(tag=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 262 | |
| 263 | Creates a tree iterator with the current element as the root. The iterator |
Alexandre Vassalotti | 6d3dfc3 | 2009-07-29 19:54:39 +0000 | [diff] [blame] | 264 | iterates over this element and all elements below it, in document (depth first) |
| 265 | order. If *tag* is not ``None`` or ``'*'``, only elements whose tag equals |
| 266 | *tag* are returned from the iterator. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 267 | |
| 268 | |
| 269 | .. method:: Element.insert(index, element) |
| 270 | |
| 271 | Inserts a subelement at the given position in this element. |
| 272 | |
| 273 | |
| 274 | .. method:: Element.makeelement(tag, attrib) |
| 275 | |
| 276 | Creates a new element object of the same type as this element. Do not call this |
| 277 | method, use the SubElement factory function instead. |
| 278 | |
| 279 | |
| 280 | .. method:: Element.remove(subelement) |
| 281 | |
| 282 | Removes *subelement* from the element. Unlike the findXYZ methods this method |
| 283 | compares elements based on the instance identity, not on tag value or contents. |
| 284 | |
| 285 | Element objects also support the following sequence type methods for working |
| 286 | with subelements: :meth:`__delitem__`, :meth:`__getitem__`, :meth:`__setitem__`, |
| 287 | :meth:`__len__`. |
| 288 | |
Georg Brandl | f694518 | 2008-02-01 11:56:49 +0000 | [diff] [blame] | 289 | Caution: Because Element objects do not define a :meth:`__bool__` method, |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 290 | elements with no subelements will test as ``False``. :: |
| 291 | |
| 292 | element = root.find('foo') |
| 293 | |
| 294 | if not element: # careful! |
Collin Winter | c79461b | 2007-09-01 23:34:30 +0000 | [diff] [blame] | 295 | print("element not found, or element has no subelements") |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 296 | |
| 297 | if element is None: |
Collin Winter | c79461b | 2007-09-01 23:34:30 +0000 | [diff] [blame] | 298 | print("element not found") |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 299 | |
| 300 | |
| 301 | .. _elementtree-elementtree-objects: |
| 302 | |
| 303 | ElementTree Objects |
| 304 | ------------------- |
| 305 | |
| 306 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 307 | .. class:: ElementTree(element=None, file=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 308 | |
| 309 | ElementTree wrapper class. This class represents an entire element hierarchy, |
| 310 | and adds some extra support for serialization to and from standard XML. |
| 311 | |
| 312 | *element* is the root element. The tree is initialized with the contents of the |
| 313 | XML *file* if given. |
| 314 | |
| 315 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 316 | .. method:: _setroot(element) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 317 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 318 | Replaces the root element for this tree. This discards the current |
| 319 | contents of the tree, and replaces it with the given element. Use with |
| 320 | care. *element* is an element instance. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 321 | |
| 322 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 323 | .. method:: find(path) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 324 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 325 | Finds the first toplevel element with given tag. Same as |
| 326 | getroot().find(path). *path* is the element to look for. Returns the |
| 327 | first matching element, or ``None`` if no element was found. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 328 | |
| 329 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 330 | .. method:: findall(path) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 331 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 332 | Finds all toplevel elements with the given tag. Same as |
| 333 | getroot().findall(path). *path* is the element to look for. Returns a |
| 334 | list or :term:`iterator` containing all matching elements, in document |
| 335 | order. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 336 | |
| 337 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 338 | .. method:: findtext(path, default=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 339 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 340 | Finds the element text for the first toplevel element with given tag. |
| 341 | Same as getroot().findtext(path). *path* is the toplevel element to look |
| 342 | for. *default* is the value to return if the element was not |
| 343 | found. Returns the text content of the first matching element, or the |
| 344 | default value no element was found. Note that if the element has is |
| 345 | found, but has no text content, this method returns an empty string. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 346 | |
| 347 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 348 | .. method:: getiterator(tag=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 349 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 350 | Creates and returns a tree iterator for the root element. The iterator |
| 351 | loops over all elements in this tree, in section order. *tag* is the tag |
| 352 | to look for (default is to return all elements) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 353 | |
| 354 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 355 | .. method:: getroot() |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 356 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 357 | Returns the root element for this tree. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 358 | |
| 359 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 360 | .. method:: parse(source, parser=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 361 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 362 | Loads an external XML section into this element tree. *source* is a file |
| 363 | name or file object. *parser* is an optional parser instance. If not |
| 364 | given, the standard XMLTreeBuilder parser is used. Returns the section |
| 365 | root element. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 366 | |
| 367 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 368 | .. method:: write(file, encoding=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 369 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 370 | Writes the element tree to a file, as XML. *file* is a file name, or a |
| 371 | file object opened for writing. *encoding* [1]_ is the output encoding |
| 372 | (default is US-ASCII). |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 373 | |
Christian Heimes | d8654cf | 2007-12-02 15:22:16 +0000 | [diff] [blame] | 374 | This is the XML file that is going to be manipulated:: |
| 375 | |
| 376 | <html> |
| 377 | <head> |
| 378 | <title>Example page</title> |
| 379 | </head> |
| 380 | <body> |
Georg Brandl | 48310cd | 2009-01-03 21:18:54 +0000 | [diff] [blame] | 381 | <p>Moved to <a href="http://example.org/">example.org</a> |
Christian Heimes | d8654cf | 2007-12-02 15:22:16 +0000 | [diff] [blame] | 382 | or <a href="http://example.com/">example.com</a>.</p> |
| 383 | </body> |
| 384 | </html> |
| 385 | |
| 386 | Example of changing the attribute "target" of every link in first paragraph:: |
| 387 | |
| 388 | >>> from xml.etree.ElementTree import ElementTree |
| 389 | >>> tree = ElementTree() |
| 390 | >>> tree.parse("index.xhtml") |
| 391 | <Element html at b7d3f1ec> |
| 392 | >>> p = tree.find("body/p") # Finds first occurrence of tag p in body |
| 393 | >>> p |
| 394 | <Element p at 8416e0c> |
| 395 | >>> links = p.getiterator("a") # Returns list of all links |
| 396 | >>> links |
| 397 | [<Element a at b7d4f9ec>, <Element a at b7d4fb0c>] |
| 398 | >>> for i in links: # Iterates through all found links |
| 399 | ... i.attrib["target"] = "blank" |
| 400 | >>> tree.write("output.xhtml") |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 401 | |
| 402 | .. _elementtree-qname-objects: |
| 403 | |
| 404 | QName Objects |
| 405 | ------------- |
| 406 | |
| 407 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 408 | .. class:: QName(text_or_uri, tag=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 409 | |
| 410 | QName wrapper. This can be used to wrap a QName attribute value, in order to |
| 411 | get proper namespace handling on output. *text_or_uri* is a string containing |
| 412 | the QName value, in the form {uri}local, or, if the tag argument is given, the |
| 413 | URI part of a QName. If *tag* is given, the first argument is interpreted as an |
| 414 | URI, and this argument is interpreted as a local name. :class:`QName` instances |
| 415 | are opaque. |
| 416 | |
| 417 | |
| 418 | .. _elementtree-treebuilder-objects: |
| 419 | |
| 420 | TreeBuilder Objects |
| 421 | ------------------- |
| 422 | |
| 423 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 424 | .. class:: TreeBuilder(element_factory=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 425 | |
| 426 | Generic element structure builder. This builder converts a sequence of start, |
| 427 | data, and end method calls to a well-formed element structure. You can use this |
| 428 | class to build an element structure using a custom XML parser, or a parser for |
| 429 | some other XML-like format. The *element_factory* is called to create new |
| 430 | Element instances when given. |
| 431 | |
| 432 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 433 | .. method:: close() |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 434 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 435 | Flushes the parser buffers, and returns the toplevel document |
| 436 | element. Returns an Element instance. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 437 | |
| 438 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 439 | .. method:: data(data) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 440 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 441 | Adds text to the current element. *data* is a string. This should be |
| 442 | either an ASCII-only :class:`bytes` object or a :class:`str` object. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 443 | |
| 444 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 445 | .. method:: end(tag) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 446 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 447 | Closes the current element. *tag* is the element name. Returns the closed |
| 448 | element. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 449 | |
| 450 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 451 | .. method:: start(tag, attrs) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 452 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 453 | Opens a new element. *tag* is the element name. *attrs* is a dictionary |
| 454 | containing element attributes. Returns the opened element. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 455 | |
| 456 | |
| 457 | .. _elementtree-xmltreebuilder-objects: |
| 458 | |
| 459 | XMLTreeBuilder Objects |
| 460 | ---------------------- |
| 461 | |
| 462 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 463 | .. class:: XMLTreeBuilder(html=0, target=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 464 | |
| 465 | Element structure builder for XML source data, based on the expat parser. *html* |
| 466 | are predefined HTML entities. This flag is not supported by the current |
| 467 | implementation. *target* is the target object. If omitted, the builder uses an |
| 468 | instance of the standard TreeBuilder class. |
| 469 | |
| 470 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 471 | .. method:: close() |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 472 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 473 | Finishes feeding data to the parser. Returns an element structure. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 474 | |
| 475 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 476 | .. method:: doctype(name, pubid, system) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 477 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 478 | Handles a doctype declaration. *name* is the doctype name. *pubid* is the |
| 479 | public identifier. *system* is the system identifier. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 480 | |
| 481 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 482 | .. method:: feed(data) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 483 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 484 | Feeds data to the parser. *data* is encoded data. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 485 | |
Christian Heimes | d8654cf | 2007-12-02 15:22:16 +0000 | [diff] [blame] | 486 | :meth:`XMLTreeBuilder.feed` calls *target*\'s :meth:`start` method |
| 487 | for each opening tag, its :meth:`end` method for each closing tag, |
Georg Brandl | 48310cd | 2009-01-03 21:18:54 +0000 | [diff] [blame] | 488 | and data is processed by method :meth:`data`. :meth:`XMLTreeBuilder.close` |
| 489 | calls *target*\'s method :meth:`close`. |
| 490 | :class:`XMLTreeBuilder` can be used not only for building a tree structure. |
Christian Heimes | d8654cf | 2007-12-02 15:22:16 +0000 | [diff] [blame] | 491 | This is an example of counting the maximum depth of an XML file:: |
| 492 | |
| 493 | >>> from xml.etree.ElementTree import XMLTreeBuilder |
| 494 | >>> class MaxDepth: # The target object of the parser |
| 495 | ... maxDepth = 0 |
| 496 | ... depth = 0 |
| 497 | ... def start(self, tag, attrib): # Called for each opening tag. |
Georg Brandl | 48310cd | 2009-01-03 21:18:54 +0000 | [diff] [blame] | 498 | ... self.depth += 1 |
Christian Heimes | d8654cf | 2007-12-02 15:22:16 +0000 | [diff] [blame] | 499 | ... if self.depth > self.maxDepth: |
| 500 | ... self.maxDepth = self.depth |
| 501 | ... def end(self, tag): # Called for each closing tag. |
| 502 | ... self.depth -= 1 |
Georg Brandl | 48310cd | 2009-01-03 21:18:54 +0000 | [diff] [blame] | 503 | ... def data(self, data): |
Christian Heimes | d8654cf | 2007-12-02 15:22:16 +0000 | [diff] [blame] | 504 | ... pass # We do not need to do anything with data. |
| 505 | ... def close(self): # Called when all data has been parsed. |
| 506 | ... return self.maxDepth |
Georg Brandl | 48310cd | 2009-01-03 21:18:54 +0000 | [diff] [blame] | 507 | ... |
Christian Heimes | d8654cf | 2007-12-02 15:22:16 +0000 | [diff] [blame] | 508 | >>> target = MaxDepth() |
| 509 | >>> parser = XMLTreeBuilder(target=target) |
| 510 | >>> exampleXml = """ |
| 511 | ... <a> |
| 512 | ... <b> |
| 513 | ... </b> |
| 514 | ... <b> |
| 515 | ... <c> |
| 516 | ... <d> |
| 517 | ... </d> |
| 518 | ... </c> |
| 519 | ... </b> |
| 520 | ... </a>""" |
| 521 | >>> parser.feed(exampleXml) |
| 522 | >>> parser.close() |
| 523 | 4 |
Christian Heimes | b186d00 | 2008-03-18 15:15:01 +0000 | [diff] [blame] | 524 | |
| 525 | |
| 526 | .. rubric:: Footnotes |
| 527 | |
| 528 | .. [#] The encoding string included in XML output should conform to the |
| 529 | appropriate standards. For example, "UTF-8" is valid, but "UTF8" is |
| 530 | not. See http://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl |
Benjamin Peterson | ad3d5c2 | 2009-02-26 03:38:59 +0000 | [diff] [blame] | 531 | and http://www.iana.org/assignments/character-sets. |
Christian Heimes | b186d00 | 2008-03-18 15:15:01 +0000 | [diff] [blame] | 532 | |