time2relax: Python CouchDB Driver

A CouchDB driver for Python.

time2relax is a Python CouchDB driver that tries to offer a minimal level of abstraction between you and CouchDB.

Basic insert usage:

>>> from time2relax import CouchDB
>>> db = CouchDB('http://localhost:5984/dbname')
>>> db.insert({'title': 'Ziggy Stardust'})
<Response [201]>

Feature Support

Inspired by pouchdb and couchdb-nano APIs, it features:

• Requests (HTTP for Humans) under the hood.
• Transparent URL and parameter encoding.
• HTTP exceptions modeled from CouchDB error codes.
• Support for CouchDB 1.7.x.

time2relax officially supports Python 3.6+.

Installation

To install time2relax, simply run:

$ pip install -U time2relax
✨🛋✨

Documentation

To use time2relax in a project:

>>> from time2relax import CouchDB
>>> db = CouchDB('http://localhost:5984/dbname')

Most of the API is exposed as db.FUNCTION(*args, **kwargs), where **kwargs are optional arguments that requests.Session.request can take.

Create a Database

Initially the CouchDB object will check if the database exists, and try to create it if it does not. You can use create_db=False to skip this step:

>>> db = CouchDB('http://localhost:5984/dbname', create_db=False)

Delete a Database

Delete a database:

>>> db.destroy()
<Response [200]>

Further requests with the CouchDB object should raise a time2relax.ResourceNotFound:

>>> db.info()
ResourceNotFound: ({'error': 'not_found', 'reason': 'missing'}, <Response [404]>)

Create/Update a Document

Note: There are some CouchDB restrictions on valid property names of the documents.

Create a new document:

>>> db.insert({'_id': 'docid', 'title': 'Heros'})
<Response [201]>

To create a new document and let CouchDB auto-generate an _id for it:

>>> db.insert({'title': 'Ziggy Stardust'})
<Response [201]>

If the document already exists, you must specify its revision _rev, otherwise a conflict will occur. You can update an existing document using _rev:

>>> result = db.get('docid').json()
>>> db.insert({'_id': result['_id'], '_rev': result['_rev'], 'title': 'Dance'})
<Response [201]>

Fetch a Document

Retrieve a document:

>>> db.get('docid')
<Response [200]>

Delete a Document

You must supply the _rev of the existing document.

Delete a document:

>>> result = db.get('docid').json()
>>> db.remove(result['_id'], result['_rev'])
<Response [200]>

You can also delete a document by using time2relax.CouchDB.insert with {'_deleted': True}:

>>> result = db.get('docid').json()
>>> result['_deleted'] = True
>>> db.insert(result)
<Response [200]>

Create/Update a Batch of Documents

Create multiple documents:

>>> db.bulk_docs([
...     {'_id': 'doc1', 'title': 'Lisa Says'},
...     {'_id': 'doc2', 'title': 'Space Oddity'},
... ])
<Response [201]>

If you omit the _id parameter on a given document, the database will create a new document and assign the ID for you:

>>> db.bulk_docs([
...     {'title': 'Lisa Says'},
...     {'title': 'Space Oddity'},
... ])
<Response [201]>

To update a document, you must include both an _id parameter and a _rev parameter, which should match the ID and revision of the document on which to base your updates:

>>> db.bulk_docs([
...     {
...         '_id': 'doc1',
...         '_rev': '1-84abc2a942007bee7cf55007cba56198',
...         'title': 'Lisa Says',
...         'artist': 'Velvet Underground',
...     },
...     {
...         '_id': 'doc2',
...         '_rev': '1-7b80fc50b6af7a905f368670429a757e',
...         'title': 'Space Oddity',
...         'artist': 'David Bowie',
...     },
... ])
<Response [201]>

Finally, to delete a document, include a _deleted parameter with the value True:

>>> db.bulk_docs([
...     {
...         '_id': 'doc1',
...         '_rev': '1-84abc2a942007bee7cf55007cba56198',
...         'title': 'Lisa Says',
...         '_deleted': True,
...     },
...     {
...         '_id': 'doc2',
...         '_rev': '1-7b80fc50b6af7a905f368670429a757e',
...         'title': 'Space Oddity',
...         '_deleted': True,
...     },
... ])
<Response [201]>

Fetch a Batch of Documents

Fetch multiple documents:

>>> params = {'include_docs': True, 'attachments': True}
>>> db.all_docs(params)
<Response [200]>

You can use startkey/endkey to find all docs in a range:

>>> params = {'startkey': 'bar', 'endkey': 'quux'}
>>> db.all_docs(params)
<Response [200]>

You can also do a prefix search – i.e. "give me all the documents whose _id start with 'foo'" – by using the special high Unicode character '\uffff':

>>> params = {'startkey': 'foo', 'endkey': 'foo\uffff'}
>>> db.all_docs(params)
<Response [200]>

Replicate a Database

Note: The target has to exist, you can use json={'create_target': True} to create it prior to replication.

Replicate a database to a target:

>>> db.replicate_to('http://localhost:5984/otherdb')
<Response [200]>

Save an Attachment

This method will update an existing document to add an attachment, so it requires a _rev if the document already exists. If the document doesn't already exist, then this method will create an empty document containing the attachment.

Attach a text/plain file:

>>> with open('/tmp/att.txt') as fp:
...     db.insert_att('docid', None, 'att.txt', fp, 'text/plain')
...
<Response [201]>

Get an Attachment

Get attachment data:

>>> db.get_att('docid', 'att.txt')
<Response [200]>

Delete an Attachment

You must supply the _rev of the existing document.

Delete an attachment:

>>> result = db.get('docid').json()
>>> db.remove_att(result['_id'], result['_rev'], 'att.txt')
<Response [200]>

Get Database Information

Get information about a database:

>>> db.info()
<Response [200]>

Compact a Database

This reduces a database's size by removing unused and old data, namely non-leaf revisions and attachments that are no longer referenced by those revisions.

Trigger a compaction operation:

>>> db.compact()
<Response [202]>

Run a List Function

Make sure you understand how list functions work in CouchDB. A good start is the CouchDB guide entry on lists:

>>> db.insert({
...     '_id': '_design/testid',
...     'views': {
...         'viewid': {
...             'map': "function (doc) {"
...                    "    emit(doc._id, 'value');"
...                    "}",
...         },
...     },
...     'lists': {
...         'listid': "function (head, req) {"
...                   "    return 'Hello World!';"
...                   "}",
...     },
... })
<Response [201]>
>>> db.ddoc_list('testid', 'listid', 'viewid')
<Response [200]>

Run a Show Function

Make sure you understand how show functions work in CouchDB. A good start is the CouchDB guide entry on shows:

>>> db.insert({
...     '_id': '_design/testid',
...     'shows': {
...         'showid': "function (doc, req) {"
...                   "    return {body: 'relax!'}"
...                   "}",
...     },
... })
<Response [201]>
>>> db.ddoc_show('testid', 'showid')
<Response [200]>

Run a View Function

Make sure you understand how view functions work in CouchDB. A good start is the CouchDB guide entry on views:

>>> db.insert({
...     '_id': '_design/testid',
...     'views': {
...         'viewid': {
...             'map': "function (doc) {"
...                    "    emit(doc.key);"
...                    "}",
...         },
...     },
... })
<Response [201]>
>>> params = {'reduce': False, 'key': 'key2'}
>>> db.ddoc_view('testid', 'viewid', params)
<Response [200]>