Introduction

couchdb is Python package for working with CouchDB from Python code. It consists of the following main modules:

• couchdb.client: This is the client library for interfacing CouchDB servers. If you don’t know where to start, this is likely to be what you’re looking for.
• couchdb.mapping: This module provides advanced mapping between CouchDB JSON documents and Python objects.

Additionally, the couchdb.view module implements a view server for views written in Python.

There may also be more information on the project website.

Documentation

Getting started with couchdb-python

Some snippets of code to get you started with writing code against CouchDB.

Starting off:

>>> import couchdb
>>> couch = couchdb.Server()

This gets you a Server object, representing a CouchDB server. By default, it assumes CouchDB is running on localhost:5984. If your CouchDB server is running elsewhere, set it up like this:

>>> couch = couchdb.Server('http://example.com:5984/')

You can also pass authentication credentials and/or use SSL:

>>> couch = couchdb.Server('https://username:password@host:port/')

You can create a new database from Python, or use an existing database:

>>> db = couch.create('test') # newly created
>>> db = couch['mydb'] # existing

After selecting a database, create a document and insert it into the db:

>>> doc = {'foo': 'bar'}
>>> db.save(doc)
('e0658cab843b59e63c8779a9a5000b01', '1-4c6114c65e295552ab1019e2b046b10e')
>>> doc
{'_rev': '1-4c6114c65e295552ab1019e2b046b10e', 'foo': 'bar', '_id': 'e0658cab843b59e63c8779a9a5000b01'}

The save() method returns the ID and “rev” for the newly created document. You can also set your own ID by including an _id item in the document.

Getting the document out again is easy:

>>> db['e0658cab843b59e63c8779a9a5000b01']
<Document 'e0658cab843b59e63c8779a9a5000b01'@'1-4c6114c65e295552ab1019e2b046b10e' {'foo': 'bar'}>

To find all your documents, simply iterate over the database:

>>> for id in db:
...     print id
...
'e0658cab843b59e63c8779a9a5000b01'

Now we can clean up the test document and database we created:

>>> db.delete(doc)
>>> couch.delete('test')

Writing views in Python

The couchdb-python package comes with a view server to allow you to write views in Python instead of JavaScript. When couchdb-python is installed, it will install a script called couchpy that runs the view server. To enable this for your CouchDB server, add the following section to local.ini:

[query_servers]
python=/usr/bin/couchpy

After restarting CouchDB, the Futon view editor should show python in the language pull-down menu. Here’s some sample view code to get you started:

def fun(doc):
    if 'date' in doc:
        yield doc['date'], doc

Note that the map function uses the Python yield keyword to emit values, where JavaScript views use an emit() function.

Basic CouchDB API: couchdb.client

Python client API for CouchDB.

>>> server = Server()
>>> db = server.create('python-tests')
>>> doc_id, doc_rev = db.save({'type': 'Person', 'name': 'John Doe'})
>>> doc = db[doc_id]
>>> doc['type']
u'Person'
>>> doc['name']
u'John Doe'
>>> del db[doc.id]
>>> doc.id in db
False

>>> del server['python-tests']

Server

class couchdb.client.Server(url='http://localhost:5984/', full_commit=True, session=None)

Representation of a CouchDB server.

>>> server = Server() # connects to the local_server
>>> remote_server = Server('http://example.com:5984/')
>>> secure_remote_server = Server('https://username:password@example.com:5984/')

This class behaves like a dictionary of databases. For example, to get a list of database names on the server, you can simply iterate over the server object.

New databases can be created using the create method:

>>> db = server.create('python-tests')
>>> db
<Database 'python-tests'>

You can access existing databases using item access, specifying the database name as the key:

>>> db = server['python-tests']
>>> db.name
'python-tests'

Databases can be deleted using a del statement:

>>> del server['python-tests']

add_user(name, password, roles=None)

Add regular user in authentication database.

Parameters:

• name – name of regular user, normally user id
• password – password of regular user
• roles – roles of regular user

Returns:

(id, rev) tuple of the registered user

Return type:

tuple

config()

The configuration of the CouchDB server.

The configuration is represented as a nested dictionary of sections and options from the configuration files of the server, or the default values for options that are not explicitly configured.

Return type:dict

create(name)

Create a new database with the given name.

Parameters:name – the name of the database Returns:a Database object representing the created database Return type:Database Raises:PreconditionFailed – if a database with that name already exists

delete(name)

Delete the database with the specified name.

Parameters:name – the name of the database Raises:ResourceNotFound – if a database with that name does not exist Since:0.6

login(name, password)

Login regular user in couch db

Parameters:

• name – name of regular user, normally user id
• password – password of regular user

Returns:

authentication token

logout(token)

Logout regular user in couch db

Parameters:token – token of login user Returns:True if successfully logout Return type:bool

remove_user(name)

Remove regular user in authentication database.

Parameters:name – name of regular user, normally user id

replicate(source, target, **options)

Replicate changes from the source database to the target database.

Parameters:

• source – URL of the source database
• target – URL of the target database
• options – optional replication args, e.g. continuous=True

stats(name=None)

Server statistics.

Parameters:name – name of single statistic, e.g. httpd/requests (None – return all statistics)

tasks()

A list of tasks currently active on the server.

uuids(count=None)

Retrieve a batch of uuids

Parameters:count – a number of uuids to fetch (None – get as many as the server sends) Returns:a list of uuids

verify_token(token)

Verify user token

Parameters:token – authentication token Returns:True if authenticated ok Return type:bool

version()

The version string of the CouchDB server.

Note that this results in a request being made, and can also be used to check for the availability of the server.

Return type:unicode

version_info()

The version of the CouchDB server as a tuple of ints.

Note that this results in a request being made only at the first call. Afterwards the result will be cached.

Return type:tuple(int, int, int)

Database

class couchdb.client.Database(url, name=None, session=None)

Representation of a database on a CouchDB server.

>>> server = Server()
>>> db = server.create('python-tests')

New documents can be added to the database using the save() method:

>>> doc_id, doc_rev = db.save({'type': 'Person', 'name': 'John Doe'})

This class provides a dictionary-like interface to databases: documents are retrieved by their ID using item access

>>> doc = db[doc_id]
>>> doc                 
<Document u'...'@... {...}>

Documents are represented as instances of the Row class, which is basically just a normal dictionary with the additional attributes id and rev:

>>> doc.id, doc.rev     
(u'...', ...)
>>> doc['type']
u'Person'
>>> doc['name']
u'John Doe'

To update an existing document, you use item access, too:

>>> doc['name'] = 'Mary Jane'
>>> db[doc.id] = doc

The save() method creates a document with a random ID generated by CouchDB (which is not recommended). If you want to explicitly specify the ID, you’d use item access just as with updating:

>>> db['JohnDoe'] = {'type': 'person', 'name': 'John Doe'}

>>> 'JohnDoe' in db
True
>>> len(db)
2

>>> del server['python-tests']

If you need to connect to a database with an unverified or self-signed SSL certificate, you can re-initialize your ConnectionPool as follows (only applicable for Python 2.7.9+):

>>> db.resource.session.disable_ssl_verification()

changes(**opts)

Retrieve a changes feed from the database.

Parameters:opts – optional query string parameters Returns:an iterable over change notification dicts

cleanup()

Clean up old design document indexes.

Remove all unused index files from the database storage area.

Returns:a boolean to indicate successful cleanup initiation Return type:bool

commit()

If the server is configured to delay commits, or previous requests used the special X-Couch-Full-Commit: false header to disable immediate commits, this method can be used to ensure that any non-committed changes are committed to physical storage.

compact(ddoc=None)

Compact the database or a design document’s index.

Without an argument, this will try to prune all old revisions from the database. With an argument, it will compact the index cache for all views in the design document specified.

Returns:a boolean to indicate whether the compaction was initiated successfully Return type:bool

copy(src, dest)

Copy the given document to create a new document.

Parameters:

• src – the ID of the document to copy, or a dictionary or Document object representing the source document.
• dest – either the destination document ID as string, or a dictionary or Document instance of the document that should be overwritten.

Returns:

the new revision of the destination document

Return type:

str

Since:

0.6

create(data)

Create a new document in the database with a random ID that is generated by the server.

Note that it is generally better to avoid the create() method and instead generate document IDs on the client side. This is due to the fact that the underlying HTTP POST method is not idempotent, and an automatic retry due to a problem somewhere on the networking stack may cause multiple documents being created in the database.

To avoid such problems you can generate a UUID on the client side. Python (since version 2.5) comes with a uuid module that can be used for this:

from uuid import uuid4
doc_id = uuid4().hex
db[doc_id] = {'type': 'person', 'name': 'John Doe'}

Parameters:data – the data to store in the document Returns:the ID of the created document Return type:unicode

delete(doc)

Delete the given document from the database.

Use this method in preference over __del__ to ensure you’re deleting the revision that you had previously retrieved. In the case the document has been updated since it was retrieved, this method will raise a ResourceConflict exception.

>>> server = Server()
>>> db = server.create('python-tests')

>>> doc = dict(type='Person', name='John Doe')
>>> db['johndoe'] = doc
>>> doc2 = db['johndoe']
>>> doc2['age'] = 42
>>> db['johndoe'] = doc2
>>> db.delete(doc) 
Traceback (most recent call last):
  ...
ResourceConflict: (u'conflict', u'Document update conflict.')

>>> del server['python-tests']

Parameters:doc – a dictionary or Document object holding the document data Raises:ResourceConflict – if the document was updated in the database Since:0.4.1

delete_attachment(doc, filename)

Delete the specified attachment.

Note that the provided doc is required to have a _rev field. Thus, if the doc is based on a view row, the view row would need to include the _rev field.

Parameters:

• doc – the dictionary or Document object representing the document that the attachment belongs to
• filename – the name of the attachment file

Since:

0.4.1

explain(mango_query)

Explain a mango find-query.

Note: only available for CouchDB version >= 2.0.0

More information on the mango_query structure can be found here:

http://docs.couchdb.org/en/master/api/database/find.html#db-explain

>>> server = Server()
>>> db = server.create('python-tests')
>>> db['johndoe'] = dict(type='Person', name='John Doe')
>>> db['maryjane'] = dict(type='Person', name='Mary Jane')
>>> db['gotham'] = dict(type='City', name='Gotham City')
>>> mango = {'selector': {'type': 'Person'}, 'fields': ['name']}
>>> db.explain(mango)                          
{...}
>>> del server['python-tests']

Parameters:mango_query – a dict describing criteria used to select documents Returns:the query results as a list of Document (or whatever wrapper returns) Return type:dict

find(mango_query, wrapper=None)

Execute a mango find-query against the database.

Note: only available for CouchDB version >= 2.0.0

More information on the mango_query structure can be found here:

http://docs.couchdb.org/en/master/api/database/find.html#find-selectors

>>> server = Server()
>>> db = server.create('python-tests')
>>> db['johndoe'] = dict(type='Person', name='John Doe')
>>> db['maryjane'] = dict(type='Person', name='Mary Jane')
>>> db['gotham'] = dict(type='City', name='Gotham City')
>>> mango = {'selector': {'type': 'Person'},
...          'fields': ['name'],
...          'sort':[{'name': 'asc'}]}
>>> for row in db.find(mango):                          
...    print(row['name'])                               
John Doe
Mary Jane
>>> del server['python-tests']

Parameters:

• mango_query – a dictionary describing criteria used to select documents
• wrapper – an optional callable that should be used to wrap the resulting documents

Returns:

the query results as a list of Document (or whatever wrapper returns)

get(id, default=None, **options)

Return the document with the specified ID.

Parameters:

• id – the document ID
• default – the default value to return when the document is not found

Returns:

a Row object representing the requested document, or None if no document with the ID was found

Return type:

Document

get_attachment(id_or_doc, filename, default=None)

Return an attachment from the specified doc id and filename.

Parameters:

• id_or_doc – either a document ID or a dictionary or Document object representing the document that the attachment belongs to
• filename – the name of the attachment file
• default – default value to return when the document or attachment is not found

Returns:

a file-like object with read and close methods, or the value of the default argument if the attachment is not found

Since:

0.4.1

index()

Get an object to manage the database indexes.

Returns:an Indexes object to manage the databes indexes Return type:Indexes

info(ddoc=None)

Return information about the database or design document as a dictionary.

Without an argument, returns database information. With an argument, return information for the given design document.

The returned dictionary exactly corresponds to the JSON response to a GET request on the database or design document’s info URI.

Returns:a dictionary of database properties Return type:dict Since:0.4

iterview(name, batch, wrapper=None, **options)

Iterate the rows in a view, fetching rows in batches and yielding one row at a time.

Since the view’s rows are fetched in batches any rows emitted for documents added, changed or deleted between requests may be missed or repeated.

Parameters:

• name – the name of the view; for custom views, use the format design_docid/viewname, that is, the document ID of the design document and the name of the view, separated by a slash.
• batch – number of rows to fetch per HTTP request.
• wrapper – an optional callable that should be used to wrap the result rows
• options – optional query string parameters

Returns:

row generator

list(name, view, **options)

Format a view using a ‘list’ function.

Parameters:

• name – the name of the list function in the format designdoc/listname
• view – the name of the view in the format designdoc/viewname
• options – optional query string parameters

Returns:

(headers, body) tuple, where headers is a dict of headers returned from the list function and body is a readable file-like instance

name

The name of the database.

Note that this may require a request to the server unless the name has already been cached by the info() method.

Return type:basestring

purge(docs)

Perform purging (complete removing) of the given documents.

Uses a single HTTP request to purge all given documents. Purged documents do not leave any meta-data in the storage and are not replicated.

put_attachment(doc, content, filename=None, content_type=None)

Create or replace an attachment.

Note that the provided doc is required to have a _rev field. Thus, if the doc is based on a view row, the view row would need to include the _rev field.

Parameters:

• doc – the dictionary or Document object representing the document that the attachment should be added to
• content – the content to upload, either a file-like object or a string
• filename – the name of the attachment file; if omitted, this function tries to get the filename from the file-like object passed as the content argument value
• content_type – content type of the attachment; if omitted, the MIME type is guessed based on the file name extension

Since:

0.4.1

query(map_fun, reduce_fun=None, language='javascript', wrapper=None, **options)

Execute an ad-hoc query (a “temp view”) against the database.

Note: not supported for CouchDB version >= 2.0.0

>>> server = Server()
>>> db = server.create('python-tests')
>>> db['johndoe'] = dict(type='Person', name='John Doe')
>>> db['maryjane'] = dict(type='Person', name='Mary Jane')
>>> db['gotham'] = dict(type='City', name='Gotham City')
>>> map_fun = '''function(doc) {
...     if (doc.type == 'Person')
...         emit(doc.name, null);
... }'''
>>> for row in db.query(map_fun):
...     print(row.key)
John Doe
Mary Jane

>>> for row in db.query(map_fun, descending=True):
...     print(row.key)
Mary Jane
John Doe

>>> for row in db.query(map_fun, key='John Doe'):
...     print(row.key)
John Doe

>>> del server['python-tests']

Parameters:

• map_fun – the code of the map function
• reduce_fun – the code of the reduce function (optional)
• language – the language of the functions, to determine which view server to use
• wrapper – an optional callable that should be used to wrap the result rows
• options – optional query string parameters

Returns:

the view results

Return type:

ViewResults

revisions(id, **options)

Return all available revisions of the given document.

Parameters:id – the document ID Returns:an iterator over Document objects, each a different revision, in reverse chronological order, if any were found

save(doc, **options)

Create a new document or update an existing document.

If doc has no _id then the server will allocate a random ID and a new document will be created. Otherwise the doc’s _id will be used to identify the document to create or update. Trying to update an existing document with an incorrect _rev will raise a ResourceConflict exception.

Note that it is generally better to avoid saving documents with no _id and instead generate document IDs on the client side. This is due to the fact that the underlying HTTP POST method is not idempotent, and an automatic retry due to a problem somewhere on the networking stack may cause multiple documents being created in the database.

To avoid such problems you can generate a UUID on the client side. Python (since version 2.5) comes with a uuid module that can be used for this:

from uuid import uuid4
doc = {'_id': uuid4().hex, 'type': 'person', 'name': 'John Doe'}
db.save(doc)

Parameters:

• doc – the document to store
• options – optional args, e.g. batch=’ok’

Returns:

(id, rev) tuple of the save document

Return type:

tuple

show(name, docid=None, **options)

Call a ‘show’ function.

Parameters:

• name – the name of the show function in the format designdoc/showname
• docid – optional ID of a document to pass to the show function.
• options – optional query string parameters

Returns:

(headers, body) tuple, where headers is a dict of headers returned from the show function and body is a readable file-like instance

update(documents, **options)

Perform a bulk update or insertion of the given documents using a single HTTP request.

>>> server = Server()
>>> db = server.create('python-tests')
>>> for doc in db.update([
...     Document(type='Person', name='John Doe'),
...     Document(type='Person', name='Mary Jane'),
...     Document(type='City', name='Gotham City')
... ]):
...     print(repr(doc)) 
(True, u'...', u'...')
(True, u'...', u'...')
(True, u'...', u'...')

>>> del server['python-tests']

The return value of this method is a list containing a tuple for every element in the documents sequence. Each tuple is of the form (success, docid, rev_or_exc), where success is a boolean indicating whether the update succeeded, docid is the ID of the document, and rev_or_exc is either the new document revision, or an exception instance (e.g. ResourceConflict) if the update failed.

If an object in the documents list is not a dictionary, this method looks for an items() method that can be used to convert the object to a dictionary. Effectively this means you can also use this method with mapping.Document objects.

Parameters:documents – a sequence of dictionaries or Document objects, or objects providing a items() method that can be used to convert them to a dictionary Returns:an iterable over the resulting documents Return type:list Since:version 0.2

update_doc(name, docid=None, **options)

Calls server side update handler.

Parameters:

• name – the name of the update handler function in the format designdoc/updatename.
• docid – optional ID of a document to pass to the update handler.
• options – additional (optional) params to pass to the underlying http resource handler, including headers, body, and `path`. Other arguments will be treated as query string params. See couchdb.http.Resource

Returns:

(headers, body) tuple, where headers is a dict of headers returned from the list function and body is a readable file-like instance

view(name, wrapper=None, **options)

Execute a predefined view.

>>> server = Server()
>>> db = server.create('python-tests')
>>> db['gotham'] = dict(type='City', name='Gotham City')

>>> for row in db.view('_all_docs'):
...     print(row.id)
gotham

>>> del server['python-tests']

Parameters:

• name – the name of the view; for custom views, use the format design_docid/viewname, that is, the document ID of the design document and the name of the view, separated by a slash
• wrapper – an optional callable that should be used to wrap the result rows
• options – optional query string parameters

Returns:

the view results

Return type:

ViewResults

Document

class couchdb.client.Document

Representation of a document in the database.

This is basically just a dictionary with the two additional properties id and rev, which contain the document ID and revision, respectively.

id

The document ID.

Return type:basestring

rev

The document revision.

Return type:basestring

ViewResults

class couchdb.client.ViewResults(view, options)

Representation of a parameterized view (either permanent or temporary) and the results it produces.

This class allows the specification of key, startkey, and endkey options using Python slice notation.

>>> server = Server()
>>> db = server.create('python-tests')
>>> db['johndoe'] = dict(type='Person', name='John Doe')
>>> db['maryjane'] = dict(type='Person', name='Mary Jane')
>>> db['gotham'] = dict(type='City', name='Gotham City')
>>> map_fun = '''function(doc) {
...     emit([doc.type, doc.name], doc.name);
... }'''
>>> results = db.query(map_fun)

At this point, the view has not actually been accessed yet. It is accessed as soon as it is iterated over, its length is requested, or one of its rows, total_rows, or offset properties are accessed:

>>> len(results)
3

You can use slices to apply startkey and/or endkey options to the view:

>>> people = results[['Person']:['Person','ZZZZ']]
>>> for person in people:
...     print(person.value)
John Doe
Mary Jane
>>> people.total_rows, people.offset
(3, 1)

Use plain indexed notation (without a slice) to apply the key option. Note that as CouchDB makes no claim that keys are unique in a view, this can still return multiple rows:

>>> list(results[['City', 'Gotham City']])
[<Row id=u'gotham', key=[u'City', u'Gotham City'], value=u'Gotham City'>]

>>> del server['python-tests']

offset

The offset of the results from the first row in the view.

This value is 0 for reduce views.

Return type:int

rows

The list of rows returned by the view.

Return type:list

total_rows

The total number of rows in this view.

This value is None for reduce views.

Return type:int or NoneType for reduce views

update_seq

The database update sequence that the view reflects.

The update sequence is included in the view result only when it is explicitly requested using the update_seq=true query option. Otherwise, the value is None.

Return type:int or NoneType depending on the query options

Row

class couchdb.client.Row

Representation of a row as returned by database views.

doc

The associated document for the row. This is only present when the view was accessed with include_docs=True as a query parameter, otherwise this property will be None.

id

The associated Document ID if it exists. Returns None when it doesn’t (reduce results).

Mapping CouchDB documents to Python objects: couchdb.mapping

Mapping from raw JSON data structures to Python objects and vice versa.

>>> from couchdb import Server
>>> server = Server()
>>> db = server.create('python-tests')

To define a document mapping, you declare a Python class inherited from Document, and add any number of Field attributes:

>>> from datetime import datetime
>>> from couchdb.mapping import Document, TextField, IntegerField, DateTimeField
>>> class Person(Document):
...     name = TextField()
...     age = IntegerField()
...     added = DateTimeField(default=datetime.now)
>>> person = Person(name='John Doe', age=42)
>>> person.store(db) 
<Person ...>
>>> person.age
42

You can then load the data from the CouchDB server through your Document subclass, and conveniently access all attributes:

>>> person = Person.load(db, person.id)
>>> old_rev = person.rev
>>> person.name
u'John Doe'
>>> person.age
42
>>> person.added                
datetime.datetime(...)

To update a document, simply set the attributes, and then call the store() method:

>>> person.name = 'John R. Doe'
>>> person.store(db)            
<Person ...>

If you retrieve the document from the server again, you should be getting the updated data:

>>> person = Person.load(db, person.id)
>>> person.name
u'John R. Doe'
>>> person.rev != old_rev
True

>>> del server['python-tests']

Field types

class couchdb.mapping.TextField(name=None, default=None)

Mapping field for string values.

class couchdb.mapping.FloatField(name=None, default=None)

Mapping field for float values.

class couchdb.mapping.IntegerField(name=None, default=None)

Mapping field for integer values.

class couchdb.mapping.LongField(name=None, default=None)

Mapping field for long integer values.

class couchdb.mapping.BooleanField(name=None, default=None)

Mapping field for boolean values.

class couchdb.mapping.DecimalField(name=None, default=None)

Mapping field for decimal values.

class couchdb.mapping.DateField(name=None, default=None)

Mapping field for storing dates.

>>> field = DateField()
>>> field._to_python('2007-04-01')
datetime.date(2007, 4, 1)
>>> field._to_json(date(2007, 4, 1))
'2007-04-01'
>>> field._to_json(datetime(2007, 4, 1, 15, 30))
'2007-04-01'

class couchdb.mapping.DateTimeField(name=None, default=None)

Mapping field for storing date/time values.

>>> field = DateTimeField()
>>> field._to_python('2007-04-01T15:30:00Z')
datetime.datetime(2007, 4, 1, 15, 30)
>>> field._to_python('2007-04-01T15:30:00.009876Z')
datetime.datetime(2007, 4, 1, 15, 30, 0, 9876)
>>> field._to_json(datetime(2007, 4, 1, 15, 30, 0))
'2007-04-01T15:30:00Z'
>>> field._to_json(datetime(2007, 4, 1, 15, 30, 0, 9876))
'2007-04-01T15:30:00.009876Z'
>>> field._to_json(date(2007, 4, 1))
'2007-04-01T00:00:00Z'

class couchdb.mapping.DictField(mapping=None, name=None, default=None)

Field type for nested dictionaries.

>>> from couchdb import Server
>>> server = Server()
>>> db = server.create('python-tests')

>>> class Post(Document):
...     title = TextField()
...     content = TextField()
...     author = DictField(Mapping.build(
...         name = TextField(),
...         email = TextField()
...     ))
...     extra = DictField()

>>> post = Post(
...     title='Foo bar',
...     author=dict(name='John Doe',
...                 email='john@doe.com'),
...     extra=dict(foo='bar'),
... )
>>> post.store(db) 
<Post ...>
>>> post = Post.load(db, post.id)
>>> post.author.name
u'John Doe'
>>> post.author.email
u'john@doe.com'
>>> post.extra
{u'foo': u'bar'}

>>> del server['python-tests']

class couchdb.mapping.ListField(field, name=None, default=None)

Field type for sequences of other fields.

>>> from couchdb import Server
>>> server = Server()
>>> db = server.create('python-tests')

>>> class Post(Document):
...     title = TextField()
...     content = TextField()
...     pubdate = DateTimeField(default=datetime.now)
...     comments = ListField(DictField(Mapping.build(
...         author = TextField(),
...         content = TextField(),
...         time = DateTimeField()
...     )))

>>> post = Post(title='Foo bar')
>>> post.comments.append(author='myself', content='Bla bla',
...                      time=datetime.now())
>>> len(post.comments)
1
>>> post.store(db) 
<Post ...>
>>> post = Post.load(db, post.id)
>>> comment = post.comments[0]
>>> comment['author']
u'myself'
>>> comment['content']
u'Bla bla'
>>> comment['time'] 
u'...T...Z'

>>> del server['python-tests']

class couchdb.mapping.ViewField(design, map_fun, reduce_fun=None, name=None, language='javascript', wrapper=<object object>, **defaults)

Descriptor that can be used to bind a view definition to a property of a Document class.

>>> class Person(Document):
...     name = TextField()
...     age = IntegerField()
...     by_name = ViewField('people', '''\
...         function(doc) {
...             emit(doc.name, doc);
...         }''')
>>> Person.by_name
<ViewDefinition '_design/people/_view/by_name'>

>>> print(Person.by_name.map_fun)
function(doc) {
    emit(doc.name, doc);
}

That property can be used as a function, which will execute the view.

>>> from couchdb import Database
>>> db = Database('python-tests')

>>> Person.by_name(db, count=3)
<ViewResults <PermanentView '_design/people/_view/by_name'> {'count': 3}>

The results produced by the view are automatically wrapped in the Document subclass the descriptor is bound to. In this example, it would return instances of the Person class. But please note that this requires the values of the view results to be dictionaries that can be mapped to the mapping defined by the containing Document class. Alternatively, the include_docs query option can be used to inline the actual documents in the view results, which will then be used instead of the values.

If you use Python view functions, this class can also be used as a decorator:

>>> class Person(Document):
...     name = TextField()
...     age = IntegerField()
...
...     @ViewField.define('people')
...     def by_name(doc):
...         yield doc['name'], doc

>>> Person.by_name
<ViewDefinition '_design/people/_view/by_name'>

>>> print(Person.by_name.map_fun)
def by_name(doc):
    yield doc['name'], doc

Changes

Version 1.2 (2018-02-09)

• Fixed some issues relating to usage with Python 3
• Remove support for Python 2.6 and 3.x with x < 4
• Fix logging response in query server (fixes #321)
• Fix HTTP authentication password encoding (fixes #302)
• Add missing http.Forbidden error (fixes #305)
• Show doc property on Row string representation
• Add methods for mango queries and indexes
• Allow mango filters in _changes API

Version 1.1 (2016-08-05)

• Add script to load design documents from disk
• Add methods on Server for user/session management
• Add microseconds support for DateTimeFields
• Handle changes feed as emitted by CouchBase (fixes #289)
• Support Python 3 in couchdb-dump script (fixes #296)
• Expand relative URLs from Location headers (fixes #287)
• Correctly handle _rev fields in mapped documents (fixes #278)

Version 1.0.1 (2016-03-12)

• Make sure connections are correctly closed on GAE (fixes #224)
• Correctly join path parts in replicate script (fixes #269)
• Fix id and rev for some special documents
• Make it possible to disable SSL verification

Version 1.0 (2014-11-16)

• Many smaller Python 3 compatibility issues have been fixed
• Improve handling of binary attachments in the couchdb-dump tool
• Added testing via tox and support for Travis CI

Version 0.10 (2014-07-15)

• Now compatible with Python 2.7, 3.3 and 3.4
• Added batch processing for the couchdb-dump tool
• A very basic API to access the _security object
• A way to access the update_seq value on view results

Version 0.9 (2013-04-25)

• Don’t validate database names on the client side. This means some methods dealing with database names can return different exceptions than before.
• Use HTTP socket more efficiently to avoid the Nagle algorithm, greatly improving performace. Note: add the {nodelay, true} option to the CouchDB server’s httpd/socket_options config.
• Add support for show and list functions.
• Add support for calling update handlers.
• Add support for purging documents.
• Add iterview() for more efficient iteration over large view results.
• Add view cleanup API.
• Enhance Server.stats() to optionally retrieve a single set of statistics.
• Implement Session timeouts.
• Add error property to Row objects.
• Add default=None arg to mapping.Document.get() to make it a little more dict-like.
• Enhance Database.info() so it can also be used to get info for a design doc.
• Add view definition options, e.g. collation.
• Fix support for authentication in dump/load tools.
• Support non-ASCII document IDs in serialization format.
• Protect ResponseBody from being iterated/closed multiple times.
• Rename iteration method for ResponseBody chunks to iterchunks() to prevent usage for non-chunked responses.
• JSON encoding exceptions are no longer masked, resulting in better error messages.
• cjson support is now deprecated.
• Fix Row.value and Row.__repr__ to never raise exceptions.
• Fix Python view server’s reduce to handle empty map results list.
• Use locale-independent timestamp identifiers for HTTP cache.
• Don’t require setuptools/distribute to install the core package. (Still needed to install the console scripts.)

Version 0.8 (Aug 13, 2010)

• The couchdb-replicate script has changed from being a poor man’s version of continuous replication (predating it) to being a simple script to help kick off replication jobs across databases and servers.
• Reinclude all http exception types in the ‘couchdb’ package’s scope.
• Replaced epydoc API docs by more extensive Sphinx-based documentation.
• Request retries schedule and frequency are now customizable.
• Allow more kinds of request errors to trigger a retry.
• Improve wrapping of view results.
• Added a uuids() method to the client.Server class (issue 122).
• Tested with CouchDB 0.10 - 1.0 (and Python 2.4 - 2.7).

Version 0.7.0 (Apr 15, 2010)

• Breaking change: the dependency on httplib2 has been replaced by an internal couchdb.http library. This changes the API in several places. Most importantly, resource.request() now returns a 3-member tuple.
• Breaking change: couchdb.schema has been renamed to couchdb.mapping. This better reflects what is actually provided. Classes inside couchdb.mapping have been similarly renamed (e.g. Schema -> Mapping).
• Breaking change: couchdb.schema.View has been renamed to couchdb.mapping.ViewField, in order to help distinguish it from couchdb.client.View.
• Breaking change: the client.Server properties version and config have become methods in order to improve API consistency.
• Prevent schema.ListField objects from sharing the same default (issue 107).
• Added a changes() method to the client.Database class (issue 103).
• Added an optional argument to the ‘Database.compact`` method to enable view compaction (the rest of issue 37).

Version 0.6.1 (Dec 14, 2009)

• Compatible with CouchDB 0.9.x and 0.10.x.
• Removed debugging statement from json module (issue 82).
• Fixed a few bugs resulting from typos.
• Added a replicate() method to the client.Server class (issue 61).
• Honor the boundary argument in the dump script code (issue 100).
• Added a stats() method to the client.Server class.
• Added a tasks() method to the client.Server class.
• Allow slashes in path components passed to the uri function (issue 96).
• schema.DictField objects now have a separate backing dictionary for each instance of their schema.Document (issue 101).
• schema.ListField proxy objects now have a more consistent (though somewhat slower) count() method (issue 91).
• schema.ListField objects now have correct behavior for slicing operations and the pop() method (issue 92).
• Added a revisions() method to the Database class (issue 99).
• Make sure we always return UTF-8 from the view server (issue 81).

Version 0.6 (Jul 2, 2009)

• Compatible with CouchDB 0.9.x.
• schema.DictField instances no longer need to be bound to a Schema (issue 51).
• Added a config property to the client.Server class (issue 67).
• Added a compact() method to the client.Database class (issue 37).
• Changed the update() method of the client.Database class to simplify the handling of errors. The method now returns a list of (success, docid, rev_or_exc) tuples. See the docstring of that method for the details.
• schema.ListField proxy objects now support the __contains__() and index() methods (issue 77).
• The results of the query() and view() methods in the schema.Document class are now properly wrapped in objects of the class if the include_docs option is set (issue 76).
• Removed the eager option on the query() and view() methods of schema.Document. Use the include_docs option instead, which doesn’t require an additional request per document.
• Added a copy() method to the client.Database class, which translates to a HTTP COPY request (issue 74).
• Accessing a non-existing database through Server.__getitem__ now throws a ResourceNotFound exception as advertised (issue 41).
• Added a delete() method to the client.Server class for consistency (issue 64).
• The couchdb-dump tool now operates in a streaming fashion, writing one document at a time to the resulting MIME multipart file (issue 58).
• It is now possible to explicitly set the JSON module that should be used for decoding/encoding JSON data. The currently available choices are simplejson, cjson, and json (the standard library module). It is also possible to use custom decoding/encoding functions.
• Add logging to the Python view server. It can now be configured to log to a given file or the standard error stream, and the log level can be set debug to see all communication between CouchDB and the view server (issue 55).

Version 0.5 (Nov 29, 2008)

• schema.Document objects can now be used in the documents list passed to client.Database.update().
• Server.__contains__() and Database.__contains__() now use the HTTP HEAD method to avoid unnecessary transmission of data. Database.__del__() also uses HEAD to determine the latest revision of the document.
• The Database class now has a method delete() that takes a document dictionary as parameter. This method should be used in preference to __del__ as it allow conflict detection and handling.
• Added cache and timeout arguments to the client.Server initializer.
• The Database class now provides methods for deleting, retrieving, and updating attachments.
• The Python view server now exposes a log() function to map and reduce functions (issue 21).
• Handling of the rereduce stage in the Python view server has been fixed.
• The Server and Database classes now implement the __nonzero__ hook so that they produce sensible results in boolean conditions.
• The client module will now reattempt a request that failed with a “connection reset by peer” error.
• inf/nan values now raise a ValueError on the client side instead of triggering an internal server error (issue 31).
• Added a new couchdb.design module that provides functionality for managing views in design documents, so that they can be defined in the Python application code, and the design documents actually stored in the database can be kept in sync with the definitions in the code.
• The include_docs option for CouchDB views is now supported by the new doc property of row instances in view results. Thanks to Paul Davis for the patch (issue 33).
• The keys option for views is now supported (issue 35).

Version 0.4 (Jun 28, 2008)

• Updated for compatibility with CouchDB 0.8.0
• Added command-line scripts for importing/exporting databases.
• The Database.update() function will now actually perform the POST request even when you do not iterate over the results (issue 5).
• The _view prefix can now be omitted when specifying view names.

Version 0.3 (Feb 6, 2008)

• The schema.Document class now has a view() method that can be used to execute a CouchDB view and map the result rows back to objects of that schema.
• The test suite now uses the new default port of CouchDB, 5984.
• Views now return proxy objects to which you can apply slice syntax for “key”, “startkey”, and “endkey” filtering.
• Add a query() classmethod to the Document class.

Version 0.2 (Nov 21, 2007)

• Added __len__ and __iter__ to the schema.Schema class to iterate over and get the number of items in a document or compound field.
• The “version” property of client.Server now returns a plain string instead of a tuple of ints.
• The client library now identifies itself with a meaningful User-Agent string.
• schema.Document.store() now returns the document object instance, instead of just the document ID.
• The string representation of schema.Document objects is now more comprehensive.
• Only the view parameters “key”, “startkey”, and “endkey” are JSON encoded, anything else is left alone.
• Slashes in document IDs are now URL-quoted until CouchDB supports them.
• Allow the content-type to be passed for temp views via client.Database.query() so that view languages other than Javascript can be used.
• Added client.Database.update() method to bulk insert/update documents in a database.
• The view-server script wrapper has been renamed to couchpy.
• couchpy now supports --help and --version options.
• Updated for compatibility with CouchDB release 0.7.0.

Version 0.1 (Sep 23, 2007)

• First public release.

Indices and tables

• Index
• Module Index
• Search Page