/usr/share/pyshared/couchdb/design.py is in python-couchdb 0.8-0ubuntu2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 | # -*- coding: utf-8 -*-
#
# Copyright (C) 2008-2009 Christopher Lenz
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution.
"""Utility code for managing design documents."""
from copy import deepcopy
from inspect import getsource
from itertools import groupby
from operator import attrgetter
from textwrap import dedent
from types import FunctionType
__all__ = ['ViewDefinition']
__docformat__ = 'restructuredtext en'
class ViewDefinition(object):
r"""Definition of a view stored in a specific design document.
An instance of this class can be used to access the results of the view,
as well as to keep the view definition in the design document up to date
with the definition in the application code.
>>> from couchdb import Server
>>> server = Server()
>>> db = server.create('python-tests')
>>> view = ViewDefinition('tests', 'all', '''function(doc) {
... emit(doc._id, null);
... }''')
>>> view.get_doc(db)
The view is not yet stored in the database, in fact, design doc doesn't
even exist yet. That can be fixed using the `sync` method:
>>> view.sync(db)
>>> design_doc = view.get_doc(db)
>>> design_doc #doctest: +ELLIPSIS
<Document '_design/tests'@'...' {...}>
>>> print design_doc['views']['all']['map']
function(doc) {
emit(doc._id, null);
}
If you use a Python view server, you can also use Python functions instead
of code embedded in strings:
>>> def my_map(doc):
... yield doc['somekey'], doc['somevalue']
>>> view = ViewDefinition('test2', 'somename', my_map, language='python')
>>> view.sync(db)
>>> design_doc = view.get_doc(db)
>>> design_doc #doctest: +ELLIPSIS
<Document '_design/test2'@'...' {...}>
>>> print design_doc['views']['somename']['map']
def my_map(doc):
yield doc['somekey'], doc['somevalue']
Use the static `sync_many()` method to create or update a collection of
views in the database in an atomic and efficient manner, even across
different design documents.
>>> del server['python-tests']
"""
def __init__(self, design, name, map_fun, reduce_fun=None,
language='javascript', wrapper=None, **defaults):
"""Initialize the view definition.
Note that the code in `map_fun` and `reduce_fun` is automatically
dedented, that is, any common leading whitespace is removed from each
line.
:param design: the name of the design document
:param name: the name of the view
:param map_fun: the map function code
:param reduce_fun: the reduce function code (optional)
:param language: the name of the language used
:param wrapper: an optional callable that should be used to wrap the
result rows
"""
if design.startswith('_design/'):
design = design[8:]
self.design = design
self.name = name
if isinstance(map_fun, FunctionType):
map_fun = _strip_decorators(getsource(map_fun).rstrip())
self.map_fun = dedent(map_fun.lstrip('\n'))
if isinstance(reduce_fun, FunctionType):
reduce_fun = _strip_decorators(getsource(reduce_fun).rstrip())
if reduce_fun:
reduce_fun = dedent(reduce_fun.lstrip('\n'))
self.reduce_fun = reduce_fun
self.language = language
self.wrapper = wrapper
self.defaults = defaults
def __call__(self, db, **options):
"""Execute the view in the given database.
:param db: the `Database` instance
:param options: optional query string parameters
:return: the view results
:rtype: `ViewResults`
"""
merged_options = self.defaults.copy()
merged_options.update(options)
return db.view('/'.join([self.design, self.name]),
wrapper=self.wrapper, **merged_options)
def __repr__(self):
return '<%s %r>' % (type(self).__name__, '/'.join([
'_design', self.design, '_view', self.name
]))
def get_doc(self, db):
"""Retrieve and return the design document corresponding to this view
definition from the given database.
:param db: the `Database` instance
:return: a `client.Document` instance, or `None` if the design document
does not exist in the database
:rtype: `Document`
"""
return db.get('_design/%s' % self.design)
def sync(self, db):
"""Ensure that the view stored in the database matches the view defined
by this instance.
:param db: the `Database` instance
"""
type(self).sync_many(db, [self])
@staticmethod
def sync_many(db, views, remove_missing=False, callback=None):
"""Ensure that the views stored in the database that correspond to a
given list of `ViewDefinition` instances match the code defined in
those instances.
This function might update more than one design document. This is done
using the CouchDB bulk update feature to ensure atomicity of the
operation.
:param db: the `Database` instance
:param views: a sequence of `ViewDefinition` instances
:param remove_missing: whether views found in a design document that
are not found in the list of `ViewDefinition`
instances should be removed
:param callback: a callback function that is invoked when a design
document gets updated; the callback gets passed the
design document as only parameter, before that doc
has actually been saved back to the database
"""
docs = []
for design, views in groupby(views, key=attrgetter('design')):
doc_id = '_design/%s' % design
doc = db.get(doc_id, {'_id': doc_id})
orig_doc = deepcopy(doc)
languages = set()
missing = list(doc.get('views', {}).keys())
for view in views:
funcs = {'map': view.map_fun}
if view.reduce_fun:
funcs['reduce'] = view.reduce_fun
doc.setdefault('views', {})[view.name] = funcs
languages.add(view.language)
if view.name in missing:
missing.remove(view.name)
if remove_missing and missing:
for name in missing:
del doc['views'][name]
elif missing and 'language' in doc:
languages.add(doc['language'])
if len(languages) > 1:
raise ValueError('Found different language views in one '
'design document (%r)', list(languages))
doc['language'] = list(languages)[0]
if doc != orig_doc:
if callback is not None:
callback(doc)
docs.append(doc)
db.update(docs)
def _strip_decorators(code):
retval = []
beginning = True
for line in code.splitlines():
if beginning and not line.isspace():
if line.lstrip().startswith('@'):
continue
beginning = False
retval.append(line)
return '\n'.join(retval)
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