CouchDB2
CouchDB v2.x Python 3 interface in a single module.
Also a command line tool; see below.
Most, but not all, features of this module work with CouchDB version < 2.0.
Installation
The CouchDB2 module is available at PyPi.
It can be installed using pip:
$ pip install couchdb2
The module relies on requests
: http://docs.python-requests.org/en/master/
and tqdm
: https://tqdm.github.io/
Example code
import couchdb2
server = couchdb2.Server()
db = server.create("test")
doc1 = {"_id": "myid", "name": "mydoc", "level": 4}
db.put(doc1)
doc = db["myid"]
assert doc == doc1
doc2 = {"name": "another", "level": 0}
db.put(doc2)
print(doc2)
db.put_design("mydesign",
{"views":
{"name": {"map": "function (doc) {emit(doc.name, null);}"}
}
})
result = db.view("mydesign", "name", key="another", include_docs=True)
assert len(result) == 1
print(result[0].doc)
db.destroy()
News
- 1.12.0
- Added progressbar to
dump
and undump
, using tqdm
. - Corrected bug fetching attachments with names having "weird" characters.
- Corrected bug creating partitioned database; thanks to https://github.com/N-Vlahovic
- 1.11.0
- Added
db.changes()
. But not adequately tested! - Corrected returned value from
set_replicate
: JSON data rather than
response from requests
. - Refactored code: Got rid of
object_pairs_hook=dict
in json()
.
response.json()
on a separate line everywhere.
- 1.10.0
- Changed to unittest for the test script. Got rid of package
pytest
.
Added some tests. - Improved the documentation in source and README.
- Fixed setup.py.
- Added
__del__
to Server class. - Simplified
get_scheduler_docs
. - Hid module-level functions which are just help functions for the
command-line tool.
- Removed
CouchDB version >= 2.0
from some methods incorrectly
marked as such. - Changed signatures of class Database methods
__init__
, create
,
find
and explain
.
- 1.9.5
- Added
__str__
to Server class.
- 1.9.4
- 1.9.3
- 1.9.2
- 1.9.1
- 1.9.0
- Changed
put_attachment
and delete_attachment
to update the input
doc
by the new _rev
value.
- 1.8.5
- Added
ids()
: Return an iterator over all document identifiers.
- 1.8.4
- Added
get_bulk(ids)
: Get several documents in one operation.
class Server
server = Server(href="http://localhost:5984/",
username=None, password=None,
use_session=True, ca_file=None)
An instance of the class is a connection to the CouchDB server.
href
is the URL to the CouchDB server itself.username
and password
specify the CouchDB user account to use.- If
use_session
is True
, then an authenticated session is used
transparently. Otherwise, the values of username
and password
are
sent with each request. ca_file
is a path to a file or a directory containing CAs if
you need to access databases in HTTPS.
server.version
Property attribute providing the version of the CouchDB server software.
server.user_context
Property attribute providing the user context of the connection.
__str__
str(server)
Returns a simple string representation of the server interface.
__len__
len(server)
Returns the number of user-defined databases.
__iter__
for db in server: ...
Returns an iterator over all user-defined databases on the server.
__getitem__
db = server[name]
Gets the named database.
__contains__
if name in server: ...
Does the named database exist?
__call__
data = server()
Returns meta information about the server.
__del__
Clean-up: Closes the requests
session.
Not for explicit use; it is automatically called when the Python
garbage collection mechanism deletes the instance.
server.up()
Is the server up and running, ready to respond to requests?
Returns a boolean.
CouchDB version >= 2.0
server.get(name, check=True)
Gets the named database. Returns an instance of class Database
.
Raises NotFoundError
if check
is True
and the database does not exist.
server.create(name, n=3, q=8, partitioned=False)
Creates the named database. Raises CreationError
if it already exists.
name
: The name of the database.n
: The number of replicas.q
: The number of shards.partitioned
: Whether to create a partitioned database.
server.get_config(nodename="_local")
Gets the named node's configuration.
server.get_active_tasks()
Returns a list of running tasks.
server.get_cluster_setup(ensure_dbs_exists=None)
Returns the status of the node or cluster.
ensure_dbs_exists
is a list system databases to ensure exist on the
node/cluster. Defaults to ["_users","_replicator"]
.
CouchDB version >= 2.0
server.set_cluster_setup(doc)
Configures a node as a single node, as part of a cluster, or finalise a
cluster.
See the CouchDB documentation for the contents of doc
.
CouchDB version >= 2.0
server.get_membership()
Returns data about the nodes that are part of the cluster.
CouchDB version >= 2.0
server.set_replicate(doc)
Request, configure, or stop, a replication operation.
See the CouchDB documentation for the contents of doc
.
server.get_scheduler_jobs(limit=None, skip=None)
Gets a list of replication jobs.
limit
: How many results to return.skip
: How many result to skip starting at the beginning,
ordered by replication ID.
server.get_scheduler_docs(limit=None, skip=None)
Gets information about replication document states.
limit
: How many results to return.skip
: How many result to skip starting at the beginning,
ordered by document ID.
server.get_node_stats(nodename="_local")
Returns statistics for the running server.
server.get_node_system(nodename="_local")
Returns various system-level statistics for the running server.
class Database
db = Database(server, name, check=True)
An instance of the class is an interface to a CouchDB database.
server
: An instance of Server.name
: The name of the database.- If
check
is True
, then raise NotFoundError
if the the database
does not exist.
__str__
str(db)
Returns the name of the CouchDB database.
__len__
len(db)
Returns the number of documents in the database.
__contains__
if identifier in db: ...
Does a document with the given identifier exist in the database?
__iter__
for doc in db: ...
Returns an iterator over all documents in the database.
__getitem__
doc = db[id]
Returns the document with the given id.
db.exists()
Does the database exist? Returns a boolean.
db.check()
Raises NotFoundError
if the database does not exist.
db.create(n=3, q=8, partitioned=False)
Creates the database. Raises CreationError
if it already exists.
n
: The number of replicas.q
: The number of shards.partitioned
: Whether to create a partitioned database.
db.destroy()
Deletes the database and all its contents.
db.get_info()
Returns a dictionary with information about the database.
db.get_security()
Returns a dictionary with security information for the database.
db.set_security(doc)
Sets the security information for the database.
See the CouchDB documentation for the contents of doc
.
db.compact(finish=False, callback=None)
Compacts the CouchDB database by rewriting the disk database file
and removing old revisions of documents.
- If
finish
is True
, then return only when compaction is done. - In addition, if defined, the function
callback(seconds)
is called
every second until compaction is done.
db.compact_design(designname)
Compacts the view indexes associated with the named design document.
db.view_cleanup()
Removes unnecessary view index files due to changed views in
design documents of the database.
db.get(id, default=None, rev=None, revs_info=False, conflicts=False)
Returns the document with the given identifier, or the default
value
if not found.
rev
: Retrieves document of specified revision, if specified.revs_info
: Whether to include detailed information for all known
document revisions.conflicts
: Whether to include information about conflicts in
the document in the _conflicts
attribute.
db.get_bulk(ids)
Gets several documents in one operation, given a list of document identifiers,
each of which is a string (the document _id
), or a tuple of the
document (_id, _rev)
.
Returns a list of documents. If no document is found for a specified
_id
or (_id, _rev
), None
is returned in that slot of the list.
db.ids()
for identifier in db.ids(): ...
Returns an iterator over all document identifiers.
db.put(doc)
Inserts or updates the document.
If the document is already in the database, the _rev
item must
be present in the document; its value will be updated.
If the document does not contain an item _id
, it is added
having a UUID4 hex value. The _rev
item will also be added.
db.update(docs)
Performs a bulk update or insertion of the given documents using a
single HTTP request.
Returns an iterable (list) over the resulting documents.
docs
is a sequence of dictionaries or Document
objects, or
objects providing an items()
method that can be used to convert
them to a dictionary.
The return value of this method is a list containing a tuple for every
element in the docs
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.
db.delete(doc)
Deletes the document, which must contain the _id
and _rev
items.
db.purge(docs)
Performs purging (complete removal) of the given list of 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.
db.get_designs()
Returns the design documents for the database.
NOTE: CouchDB version >= 2.2
db.get_design(designname)
Gets the named design document.
db.put_design(designname, doc, rebuild=True)
Inserts or updates the design document under the given name.
If the existing design document is identical, no action is taken and
False
is returned, else the document is updated and True
is returned.
If rebuild
is True
, force view indexes to be rebuilt after update
by accessing the view. This may take some time.
Example of doc:
{"views":
{"name":
{"map": "function (doc) {emit(doc.name, null);}"},
"name_sum":
{"map": "function (doc) {emit(doc.name, 1);}",
"reduce": "_sum"},
"name_count":
{"map": "function (doc) {emit(doc.name, null);}",
"reduce": "_count"}
}}
More info: http://docs.couchdb.org/en/latest/api/ddoc/common.html
db.view(designname, viewname, **kwargs)
Query a view index to obtain data and/or documents.
Keyword arguments (default value is None
unless specified):
key
: Return only rows that match the specified key.keys
: Return only rows where they key matches one of those specified as a list.startkey
: Return rows starting with the specified key.endkey
: Stop returning rows when the specified key is reached.skip
: Skip the number of rows before starting to return rows.limit
: Limit the number of rows returned.sorted=True
: Sort the rows by the key of each returned row. The items
total_rows
and offset
are not available if set to False
.descending=False
: Return the rows in descending order.group=False
: Group the results using the reduce function of the design
document to a group or a single row. If set to True
implies reduce
to True
and defaults the group_level
to the maximum.group_level
: Specify the group level to use. Implies group
is True
.reduce
: If set to False
then do not use the reduce function if there is
one defined in the design document. Default is to use the reduce function
if defined.include_docs=False
: If True
, include the document for each row. This
will force reduce
to False
.update="true"
: Whether ir not the view should be updated prior to
returning the result. Supported value are "true"
, "false"
and "lazy"
.
Returns an instance of class ViewResult,
containing the following attributes:
rows
: The list of Row
objects.offset
: The offset used for the set of rows.total_rows
: The total number of rows selected.
A Row object contains the following attributes:
id
: The identifier of the document, if any.key
: The key for the index row.value
: The value for the index row.doc
: The document, if any.
db.get_indexes()
Returns a list of all Mango indexes in the database.
CouchDB version >= 2.0
db.put_index(fields, ddoc=None, name=None, selector=None)
Stores a Mango index specification.
fields
: A list of fields to index.ddoc
: The design document name. Generated if none given.name
: The name of the index. Generated if none given.selector
: A partial filter selector, which may be omitted.
Returns a dictionary with items id
(design document name; sic!),
name
(index name) and result
(created
or exists
).
CouchDB version >= 2.0
db.delete_index(designname, name)
Deletes the named index in the design document of the given name.
CouchDB version >= 2.0
db.find(selector, **kwargs)
data = db.find(selector, limit=25, skip=None, sort=None, fields=None,
use_index=None, bookmark=None, update=True, conflicts=False)
Selects documents according to the Mango index selector
.
selector
: The Mango index. For more information on selector syntax,
see https://docs.couchdb.org/en/latest/api/database/find.html#find-selectorslimit
: Maximum number of results returned.skip
: Skip the given number of results.sort
: A list of dictionaries specifying the order of the results,
where the field name is the key and the direction is the value;
either "asc"
or "desc"
.fields
: List specifying which fields of each result document should
be returned. If omitted, return the entire document.use_index
: String or list of strings specifying the index(es) to use.bookmark
: A string that marks the end the previous set of results.
If given, the next set of results will be returned.update
: Whether to update the index prior to returning the result.conflicts
: Whether to include conflicted documents.
Returns a dictionary with items docs
, warning
, execution_stats
and bookmark
.
CouchDB version >= 2.0
db.explain(selector, **kwargs)
data = db.explain(selector, use_index=None, limit=None, skip=None,
sort=None, fields=None, bookmark=None)
Returns info on which index is being used by the query.
selector
: The Mango index. For more information on selector syntax,
see https://docs.couchdb.org/en/latest/api/database/find.html#find-selectorslimit
: Maximum number of results returned.skip
: Skip the given number of results.sort
: A list of dictionaries specifying the order of the results,
where the field name is the key and the direction is the value;
either "asc"
or "desc"
.fields
: List specifying which fields of each result document should
be returned. If omitted, return the entire document.bookmark
: A string that marks the end the previous set of results.
If given, the next set of results will be returned.
CouchDB version >= 2.0
db.get_attachment(doc, filename)
Returns a file-like object containing the content of the specified attachment.
db.put_attachment(doc, content, filename=None, content_type=None)
Adds or updates the given file as an attachment to the given document
in the database.
content
is a string or a file-like object.- If
filename
is not provided, then an attempt is made to get it from
the content
object. If this fails, ValueError
is raised. - If
content_type
is not provided, then an attempt to guess it from
the filename extension is made. If that does not work, it is
set to "application/octet-stream"
Returns the new revision of the document, in addition to updating
the _rev
field in the document.
db.delete_attachment(doc, filename)
Deletes the attachment.
Returns the new revision of the document, in addition to updating
the _rev
field in the document.
db.dump(filepath, callback=None, exclude_designs=False, progressbar=False)
Dumps the entire database to a tar
file.
Returns a tuple (ndocs, nfiles)
giving the number of documents
and attached files written out.
If defined, the function callback(ndocs, nfiles)
is called
every 100 documents.
If exclude_designs
is True, design document will be excluded from the dump.
If progressbar
is True, display a progress bar.
If the filepath ends with .gz
, then the tar file is gzip compressed.
The _rev
item of each document is included in the dump.
db.undump(filepath, callback=None, progressbar=False)
Loads the tar
file given by the path. It must have been produced by db.dump
.
Returns a tuple (ndocs, nfiles)
giving the number of documents
and attached files read from the file.
If defined, the function callback(ndocs, nfiles)
is called
every 100 documents.
If progressbar
is True, display a progress bar.
NOTE: The documents are just added to the database, ignoring any
_rev
items. This means that no document with the same identifier
may exist in the database.
CouchDB2Exception
The Base CouchDB2 exception, from which all others derive.
NotFoundError
No such entity (e.g. database or document) exists.
BadRequestError
Invalid request; bad name, body or headers.
CreationError
Could not create the entity; it exists already.
RevisionError
Wrong or missing _rev
item in the document to save.
AuthorizationError
Current user not authorized to perform the operation.
ContentTypeError
Bad Content-Type
value in the request.
ServerError
Internal CouchDB server error.
class ViewResult(rows, offset, total_rows)
An instance of this class is returned as result from db.view()
.
Instances of this class are not supposed to be created by client software.
Attributes:
rows
: the list of Row
objects.offset
: the offset used for the set of rows.total_rows
: the total number of rows selected.
__len__
len(viewresult)
Return the number of rows in the view result.
__iter__
for row in viewresult: ...
Return an iterator over all rows in the view result.
__getitem__
row = viewresult[i]
Return the indexed view result row.
vr.json()
Return the view result data in a JSON-like representation.
class Row(id, key, value, doc)
Named-tuple object returned in ViewResult list attribute rows
.
Attributes:
id
: the identifier of the document, if any. Alias for row[0]
.key
: the key for the index row. Alias for row[1]
.value
: the value for the index row. Alias for row[2]
.doc
: the document, if any. Alias for row[3]
.
Utility functions at the module level
read_settings(filepath, settings=None)
Read the settings lookup from a JSON format file.
If settings
is given, then return an updated copy of it,
else copy the default settings, update, and return it.
Command line tool
The module is also a command line tool for interacting with the CouchDB server.
It is installed if pip
is used to install this module.
Settings for the command line tool are updated from the following sources,
each in the order given and if it exists:
- Default values are
{
"SERVER": "http://localhost:5984",
"DATABASE": null,
"USERNAME": null,
"PASSWORD": null
}
- Read from the JSON file
~/.couchdb2
(in your home directory). - Read from the JSON file
settings.json
(in the current working directory). - Read from the JSON file given by command line option
--settings FILEPATH
. - From environment variables.
- From command line arguments.
Options
To show available command options:
$ couchdb2 -h
usage: couchdb2 [options]
CouchDB v2.x command line tool, leveraging Python module CouchDB2.
optional arguments:
-h, --help show this help message and exit
--settings FILEPATH Settings file in JSON format.
-S SERVER, --server SERVER
CouchDB server URL, including port number.
-d DATABASE, --database DATABASE
Database to operate on.
-u USERNAME, --username USERNAME
CouchDB user account name.
-p PASSWORD, --password PASSWORD
CouchDB user account password.
-q, --password_question
Ask for the password by interactive input.
--ca_file FILE_OR_DIRPATH
File or directory containing CAs.
-o FILEPATH, --output FILEPATH
Write output to the given file (JSON format).
--indent INT Indentation level for JSON format output file.
-y, --yes Do not ask for confirmation (delete, destroy, undump).
-v, --verbose Print more information.
-s, --silent Print no information.
server operations:
-V, --version Output CouchDB server version.
--list Output a list of the databases on the server.
Database operations.:
--create Create the database.
--destroy Delete the database and all its contents.
--compact Compact the database; may take some time.
--compact_design DDOC
Compact the view indexes for the named design doc.
--view_cleanup Remove view index files no longer required.
--info Output information about the database.
--security Output security information for the database.
--set_security FILEPATH
Set security information for the database from the
JSON file.
--list_designs List design documents for the database.
--design DDOC Output the named design document.
--put_design DDOC FILEPATH
Store the named design document from the file.
--delete_design DDOC Delete the named design document.
--dump FILEPATH Create a dump file of the database.
--undump FILEPATH Load a dump file into the database.
Document operations.:
-G DOCID, --get DOCID
Output the document with the given identifier.
-P FILEPATH, --put FILEPATH
Store the document; arg is literal doc or filepath.
--delete DOCID Delete the document with the given identifier.
attachments to document:
--attach DOCID FILEPATH
Attach the specified file to the given document.
--detach DOCID FILENAME
Remove the attached file from the given document.
--get_attach DOCID FILENAME
Get the attached file from the given document; write
to same filepath or that given by '-o'.
query a design view, returning rows:
--view SPEC Design view '{design}/{view}' to query.
--key KEY Key value selecting view rows.
--startkey KEY Start key value selecting range of view rows.
--endkey KEY End key value selecting range of view rows.
--startkey_docid DOCID
Return rows starting with the specified document.
--endkey_docid DOCID Stop returning rows when specified document reached.
--group Group the results using the 'reduce' function.
--group_level INT Specify the group level to use.
--noreduce Do not use the 'reduce' function of the view.
--limit INT Limit the number of returned rows.
--skip INT Skip this number of rows before returning result.
--descending Sort rows in descending order (swap start/end keys!).
--include_docs Include documents in result.