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https://github.com/coleifer/vedis-python

Python bindings for the Vedis embedded NoSQL database
https://github.com/coleifer/vedis-python

cython embedded-database nosql python vedis

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Python bindings for the Vedis embedded NoSQL database

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README 

        
### WARNING:



[Vedis](https://github.com/symisc/vedis) appears to be no longer maintained by symisc.



![](http://media.charlesleifer.com/blog/photos/vedis-python-logo.png)



Fast Python bindings for the Vedis embedded NoSQL database. Vedis is a fun, fast, embedded database modeled after Redis.



[View the vedis-python documentation](https://vedis-python.readthedocs.io/).



### Features



Vedis features:



* Embedded, zero-conf database

* Transactional (ACID)

* Single file or in-memory database

* Key/value store

* [Over 70 commands](http://vedis.symisc.net/commands.html) similar to standard [Redis](http://redis.io) commands.

* Thread-safe

* Terabyte-sized databases



Vedis-Python features:



* Compiled library, extremely fast with minimal overhead.

* Supports key/value operations and transactions using Pythonic APIs.

* Support for executing Vedis commands.

* Write custom commands in Python.

* Python 2.x and 3.x.



Limitations:



* Not tested on Windoze.



The previous version (0.2.0) of `vedis-python` utilized `ctypes` to wrap the Vedis C library. By switching to Cython, key/value and Vedis command operations are significantly faster.



Links:



* [vedis-python documentation](https://vedis-python.readthedocs.io/)

* [Vedis's C API](http://vedis.symisc.net/c_api.html)



If you like Vedis, you might also want to check out [UnQLite](http://unqlite.symisc.net), an embedded key/value database with cursors and a cool JSON document store (python bindings: [unqlite-python](https://unqlite-python.readthedocs.io)).



## Installation



You can install vedis-python using `pip`.



    pip install vedis



Basic usage

-----------



First you instantiate a `Vedis` object, passing in either the path to the database

file or the special string `':mem:'` for an in-memory database.



Below is a sample interactive console session designed to show some of the basic features and functionality of the vedis-python library. Also check out the [full API documentation](https://vedis-python.readthedocs.io/en/latest/api.html) as well as the [vedis command documentation](http://vedis.symisc.net/commands.html).



### Key/value features



You can use Vedis like a dictionary for simple key/value lookups:



```python



>>> from vedis import Vedis

>>> db = Vedis(':mem:')  # Create an in-memory database. Alternatively you could supply a filename for an on-disk database.

>>> db['k1'] = 'v1'

>>> db['k1']

'v1'



>>> db.append('k1', 'more data')  # Returns length of value after appending new data.

11

>>> db['k1']

'v1more data'



>>> del db['k1']

>>> 'k1' in db

False

>>> db['k1']

None

```



You can set and get multiple items at a time:



```python



>>> db.mset(dict(k1='v1', k2='v2', k3='v3'))

True



>>> db.mget(['k1', 'k2', 'missing key', 'k3'])

['v1', 'v2', None, 'v3']

```



In addition to storing string keys/values, you can also implement counters:



```python



>>> db.incr('counter')

1

>>> db.incr('counter')

2



>>> db.incr_by('counter', 10)

12

>>> db.decr('counter')

11

```



### Hashes



Vedis supports nested key/value lookups which have the additional benefit of supporting operations to retrieve all keys, values, the number of items in the hash, and so on.



```python



>>> h = db.Hash('some key')

>>> h['k1'] = 'v1'

>>> h.update(k2='v2', k3='v3')



>>> h



>>> h.to_dict()

{'k3': 'v3', 'k2': 'v2', 'k1': 'v1'}



>>> h.items()

[('k1', 'v1'), ('k3', 'v3'), ('k2', 'v2')]



>>> h.keys()

['k1', 'k3', 'k2']



>>> del h['k2']



>>> len(h)

2



>>> 'k1' in h

True



>>> [key for key in h]

['k1', 'k3']

```



### Sets



Vedis supports a set data-type which stores a unique collection of items.



```python



>>> s = db.Set('some set')

>>> s.add('v1', 'v2', 'v3')

3



>>> len(s)

3



>>> 'v1' in s, 'v4' in s

(True, False)



>>> s.top()

'v1'



>>> s.peek()

'v3'



>>> del s['v2']

1



>>> s.add('v4', 'v5')

2



>>> s.pop()

'v5'



>>> [item for item in s]

['v1', 'v3', 'v4']



>>> s.to_set()

set(['v1', 'v3', 'v4'])



>>> s2 = db.Set('another set')

>>> s2.add('v1', 'v4', 'v5', 'v6')

4



>>> s2 & s  # Intersection.

set(['v1', 'v4'])



>>> s2 - s  # Difference.

set(['v5', 'v6'])

```



### Lists



Vedis also supports a list data type.



```python



>>> l = db.List('my list')

>>> l.append('v1')

1

>>> l.extend(['v2', 'v3', 'v4'])

4



>>> len(l)

4



>>> l[1]

'v2'



>>> l.pop(), l.pop()

('v1', 'v2')



>>> len(l)

2

```



### Misc



Vedis has a somewhat quirky collection of other miscellaneous commands. Below is a sampling:



```python



>>> db.base64('encode me')

'ZW5jb2RlIG1l'



>>> db.base64_decode('ZW5jb2RlIG1l')

'encode me'



>>> db.random_string(10)

'raurquvsnx'



>>> db.rand(1, 6)

4



>>> db.str_split('abcdefghijklmnop', 5)

['abcde', 'fghij', 'klmno', 'p']



>>> db['data'] = 'abcdefghijklmnop'

>>> db.strlen('data')

16



>>> db.strip_tags('
This is a test.
')

'This is a test.'

```



### Writing your own Vedis commands



It is easy to write your own Vedis commands:



```python



db = Vedis()



@db.register('CONCAT')

def concat(context, glue, *params):

    return glue.join(params)



@db.register('TITLE')

def title(context, *params):

    # The `context` can be used to access the key/value store.

    for param in params:

        context[param] = param.title()

    return True

```



Here is how you might call the custom commands:



```python



>>> print db.execute('CONCAT | foo bar baz')

foo|bar|baz



>>> db.execute('TITLE "testing" "this is a test" "another"')

True

>>> print db['testing']

Testing

>>> print db['this is a test']

This Is A Test



>>> title('foo', 'bar')  # Calling the wrapped function will go through Vedis.

True

>>> print db['foo']

Foo

>>> print db['bar']

Bar

```



-------------------------------------------



This code is based in part on [buaabyl's pyUnQLite](https://github.com/buaabyl/pyUnQLite/).