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| author | Tom Christie | 2012-09-20 13:06:27 +0100 |
|---|---|---|
| committer | Tom Christie | 2012-09-20 13:06:27 +0100 |
| commit | 4b691c402707775c3048a90531024f3bc5be6f91 (patch) | |
| tree | 3adfc54b0d8b70e4ea78edf7091f7827fa68f47b /rest_framework/parsers.py | |
| parent | a1bcfbfe926621820832e32b0427601e1140b4f7 (diff) | |
| download | django-rest-framework-4b691c402707775c3048a90531024f3bc5be6f91.tar.bz2 | |
Change package name: djangorestframework -> rest_framework
Diffstat (limited to 'rest_framework/parsers.py')
| -rw-r--r-- | rest_framework/parsers.py | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/rest_framework/parsers.py b/rest_framework/parsers.py new file mode 100644 index 00000000..b3423131 --- /dev/null +++ b/rest_framework/parsers.py @@ -0,0 +1,260 @@ +""" +Django supports parsing the content of an HTTP request, but only for form POST requests. +That behavior is sufficient for dealing with standard HTML forms, but it doesn't map well +to general HTTP requests. + +We need a method to be able to: + +1.) Determine the parsed content on a request for methods other than POST (eg typically also PUT) + +2.) Determine the parsed content on a request for media types other than application/x-www-form-urlencoded + and multipart/form-data. (eg also handle multipart/json) +""" + +from django.http import QueryDict +from django.http.multipartparser import MultiPartParser as DjangoMultiPartParser +from django.http.multipartparser import MultiPartParserError +from django.utils import simplejson as json +from rest_framework.compat import yaml +from rest_framework.exceptions import ParseError +from rest_framework.utils.mediatypes import media_type_matches +from xml.etree import ElementTree as ET +from rest_framework.compat import ETParseError +from xml.parsers.expat import ExpatError +import datetime +import decimal +from io import BytesIO + + +__all__ = ( + 'BaseParser', + 'JSONParser', + 'PlainTextParser', + 'FormParser', + 'MultiPartParser', + 'YAMLParser', + 'XMLParser' +) + + +class DataAndFiles(object): + def __init__(self, data, files): + self.data = data + self.files = files + + +class BaseParser(object): + """ + All parsers should extend :class:`BaseParser`, specifying a :attr:`media_type` attribute, + and overriding the :meth:`parse` method. + """ + + media_type = None + + def can_handle_request(self, content_type): + """ + Returns :const:`True` if this parser is able to deal with the given *content_type*. + + The default implementation for this function is to check the *content_type* + argument against the :attr:`media_type` attribute set on the class to see if + they match. + + This may be overridden to provide for other behavior, but typically you'll + instead want to just set the :attr:`media_type` attribute on the class. + """ + return media_type_matches(self.media_type, content_type) + + def parse(self, string_or_stream, **opts): + """ + The main entry point to parsers. This is a light wrapper around + `parse_stream`, that instead handles both string and stream objects. + """ + if isinstance(string_or_stream, basestring): + stream = BytesIO(string_or_stream) + else: + stream = string_or_stream + return self.parse_stream(stream, **opts) + + def parse_stream(self, stream, **opts): + """ + Given a *stream* to read from, return the deserialized output. + Should return parsed data, or a DataAndFiles object consisting of the + parsed data and files. + """ + raise NotImplementedError(".parse_stream() must be overridden.") + + +class JSONParser(BaseParser): + """ + Parses JSON-serialized data. + """ + + media_type = 'application/json' + + def parse_stream(self, stream, **opts): + """ + Returns a 2-tuple of `(data, files)`. + + `data` will be an object which is the parsed content of the response. + `files` will always be `None`. + """ + try: + return json.load(stream) + except ValueError, exc: + raise ParseError('JSON parse error - %s' % unicode(exc)) + + +class YAMLParser(BaseParser): + """ + Parses YAML-serialized data. + """ + + media_type = 'application/yaml' + + def parse_stream(self, stream, **opts): + """ + Returns a 2-tuple of `(data, files)`. + + `data` will be an object which is the parsed content of the response. + `files` will always be `None`. + """ + try: + return yaml.safe_load(stream) + except (ValueError, yaml.parser.ParserError), exc: + raise ParseError('YAML parse error - %s' % unicode(exc)) + + +class PlainTextParser(BaseParser): + """ + Plain text parser. + """ + + media_type = 'text/plain' + + def parse_stream(self, stream, **opts): + """ + Returns a 2-tuple of `(data, files)`. + + `data` will simply be a string representing the body of the request. + `files` will always be `None`. + """ + return stream.read() + + +class FormParser(BaseParser): + """ + Parser for form data. + """ + + media_type = 'application/x-www-form-urlencoded' + + def parse_stream(self, stream, **opts): + """ + Returns a 2-tuple of `(data, files)`. + + `data` will be a :class:`QueryDict` containing all the form parameters. + `files` will always be :const:`None`. + """ + data = QueryDict(stream.read()) + return data + + +class MultiPartParser(BaseParser): + """ + Parser for multipart form data, which may include file data. + """ + + media_type = 'multipart/form-data' + + def parse_stream(self, stream, **opts): + """ + Returns a DataAndFiles object. + + `.data` will be a `QueryDict` containing all the form parameters. + `.files` will be a `QueryDict` containing all the form files. + """ + meta = opts['meta'] + upload_handlers = opts['upload_handlers'] + try: + parser = DjangoMultiPartParser(meta, stream, upload_handlers) + data, files = parser.parse() + return DataAndFiles(data, files) + except MultiPartParserError, exc: + raise ParseError('Multipart form parse error - %s' % unicode(exc)) + + +class XMLParser(BaseParser): + """ + XML parser. + """ + + media_type = 'application/xml' + + def parse_stream(self, stream, **opts): + try: + tree = ET.parse(stream) + except (ExpatError, ETParseError, ValueError), exc: + raise ParseError('XML parse error - %s' % unicode(exc)) + data = self._xml_convert(tree.getroot()) + + return data + + def _xml_convert(self, element): + """ + convert the xml `element` into the corresponding python object + """ + + children = element.getchildren() + + if len(children) == 0: + return self._type_convert(element.text) + else: + # if the fist child tag is list-item means all children are list-item + if children[0].tag == "list-item": + data = [] + for child in children: + data.append(self._xml_convert(child)) + else: + data = {} + for child in children: + data[child.tag] = self._xml_convert(child) + + return data + + def _type_convert(self, value): + """ + Converts the value returned by the XMl parse into the equivalent + Python type + """ + if value is None: + return value + + try: + return datetime.datetime.strptime(value, '%Y-%m-%d %H:%M:%S') + except ValueError: + pass + + try: + return int(value) + except ValueError: + pass + + try: + return decimal.Decimal(value) + except decimal.InvalidOperation: + pass + + return value + + +DEFAULT_PARSERS = ( + JSONParser, + FormParser, + MultiPartParser, + XMLParser +) + +if yaml: + DEFAULT_PARSERS += (YAMLParser, ) +else: + YAMLParser = None |
