indexedredis 3.1.0

API Reference

Most, but not all methods are documented here.

See: This Page for full documentation as a pydoc document.

Below is a quick highlight/overview

IndexedRedisModel

This is the model you should extend.

Example Model:

class Song(IndexedRedisModel):

FIELDS = [ \

‘artist’,

‘title’,

‘album’,

‘track_number’,

‘duration’,

‘description’,

‘copyright’,

‘mp3_data’,

]

INDEXED_FIELDS = [ \

‘artist’,

‘title’,

‘track_number’,

]

BINARY_FIELDS = [ ‘mp3_data’, ]

KEY_NAME = ‘Songs’

Model Fields:

FIELDS - REQUIRED. A list of strings which name the fields that can be used for storage.

Example: [‘Name’, ‘Description’, ‘Model’, ‘Price’]

INDEXED_FIELDS - A list of strings containing the names of fields that will be indexed. Can only filter on indexed fields. Adds insert/delete time. Entries must also be present in FIELDS.

Example: [‘Name’, ‘Model’]

BINARY_FIELDS - A list of strings containing the names of fields which will be stored directly as unencoded bytes. This is generally faster and more space-efficient than using BASE64_FIELDS, and should be used for purely binary data.

Example: [‘picture’, ‘mp3_data’]

BASE64_FIELDS - A lsit of strings containing the names of fields which will be automatically converted to/from base64 for storage. This allows you to store binary data, e.x. audio or pictures.

Example: [‘picture’, ‘mp3_data’]

KEY_NAME - REQUIRED. A unique name name that represents this model. Think of it like a table name.

Example: ‘Items’

REDIS_CONNECTION_PARAMS - provides the arguments to pass into “redis.Redis”, to construct a redis object.

Example: {‘host’ : ‘192.168.1.1’}

Model Validation

The model will be validated the first time an object of that type is instantiated. If there is something invalid in how it is defined, an “InvalidModelException” will be raised.

Usage

Usage is very similar to Django or Flask

Query:

Calling .filter or .filterInline builds a query/filter set. Use one of the Fetch methods described below to execute a query.

objects = SomeModel.objects.filter(param1=val).filter(param2=val).all()

Supported fetch types from the database are equals and not-equals. To use a not-equals expression, append “__ne” to the end of the field name.

objects = SomeModel.objects.filter(param1=val, param2__ne=val2).all()

All filters are applied on the redis server using hash lookups. All filters of the same type (equals or not equals) are applied in one command to Redis. So applying filters, no matter how many filters, is one to two commands total.

Filter Results / client-side filtering:

The results from the .all operation is a QueryableList of all matched objects. The type of each object is the same as the model. You can use a QueryableList same as a normal list, but it can be more powerful than that:

Once you have fetched the results from Redis, the QueryableList allows you to perform further client-side filtering using any means that QueryableList supports (e.x. gt, contains, in).

Example:

mathTeachers = People.objects.filter(job=’Math Teacher’).all()

experiencedMathTeachers = mathTeachers.filter(experienceYears__gte=10) # Get math teachers with greater than or equal to 10 years experience

cheeseLovingMathTeachers = matchTeachers.filter(likes__splitcontains=(’ ‘, ‘cheese’)) # Check a space-separated list field, ‘likes’, and see if it contains ‘cheese’

See https://github.com/kata198/QueryableList for more information.

Save:

obj = SomeModel(field1=’value’, field2=’value’) obj.save()

Delete Using Filters:

SomeModel.objects.filter(name=’Bad Man’).delete()

Delete Individual Objects:

obj.delete()

Atomic Dataset Replacement:

There is also a powerful method called “reset” which will atomically replace all elements belonging to a model. This is useful for cache-replacement, etc.

lst = [SomeModel(…), SomeModel(..)]

SomeModel.reset(lst)

For example, you could have a SQL backend and a cron job that does complex queries (or just fetches the same models) and does an atomic replace every 5 minutes to get massive performance boosts in your application.

Filter objects by SomeModel.objects.filter(key=val, key2=val2) and get objects with .all

Example: SomeModel.objects.filter(name=’Tim’, colour=’purple’).filter(number=5).all()

Get Primary Key:

Sometimes you may want to reference an individual object, via a foreign-key relationship or just to retrieve faster / unique rather than filtering.

Every object saved has a unique primary key (unique per the model) which can be retrieved by the “getPk” method. You can then use this value on exists, get, getMultiple, etc methods.

Fetch Functions:

Building filtersets do not actually fetch any data until one of these are called (see API for a complete list). All of these functions act on current filterset.

Example: matchingObjects = SomeModel.objects.filter(…).all()

all - Return all objects matching this filter

allOnlyFields - Takes a list of fields and only fetches those fields, using current filterset

delete - Delete objects matching this filter

count - Get the count of objects matching this filter

first - Get the oldest record with current filters

last - Get the newest record with current filters

random - Get a random element with current filters

getPrimaryKeys - Gets primary keys associated with current filters

Filter Functions

These functions add filters to the current set. “filter” returns a copy, “filterInline” acts on that object.

filter - Add additional filters, returning a copy of the filter object (moreFiltered = filtered.filter(key2=val2))

filterInline - Add additional filters to current filter object.

Global Fetch functions

These functions are available on SomeModel.objects and don’t use any filters (they get specific objects):

get - Get a single object by pk

getMultiple - Get multiple objects by a list of pks

exists - Tests the existance of an object under a given pk

Model Functions

Actual objects contain methods including:

save - Save this object (create if not exist, otherwise update)

delete - Delete this object

getUpdatedFields - See changes since last fetch

Update Index

As your model changes, you may need to add a field to the INDEXED_FIELDS array. If this was an already existing field, you can reindex the models by doing:

MyModel.objects.reindex()

Connecting to other Redis instances

You may want to use the same model on multiple Redis instances. To do so, use the .connect method on IndexedRedisModel.

AltConnectionMyModel = MyModel.connect({‘host’ : ‘althost’, ‘db’ : 4})

Then, use AltConnectionMyModel just as you would use MyModel.

Encodings

IndexedRedis will use by default your system default encoding (sys.getdefaultencoding), unless it is ascii (python2) in which case it will default to utf-8.

You may change this via IndexedRedis.setEncoding

Binary/Bytes Data Support

IndexedRedis, as of version 2.9.0, has the ability to store and retrieve unencoded (binary) data, e.x. image files, executables, raw device data, etc.

Add the field name to the BINARY_FIELDS array, and IndexedRedis will retrieve and store directly as binary unencoded data.

So you may have a model like this:

class FileObj(IndexedRedis.IndexedRedisModel):

FIELDS = [ ‘filename’, ‘data’, ‘description’ ]

INDEXED_FIELDS = [ ‘filename’ ]

BINARY_FIELDS = [‘data’]

Base64 Encoding Data Support

Since version 2.7.0, IndexedRedis has support for base64 encoding data, by adding the field name to the “BASE64_FIELDS” array. Use this if you want to keep your data purely text-friendly, but for most cases you should probably use BINARY_FIELDS.

Simply by adding a field to the “BASE64_FIELDS” array, IndexedRedis will transparently handle base64-encoding before store, and decoding after retrieval.

So you may have a model like this:

class FileObj(IndexedRedis.IndexedRedisModel):

FIELDS = [ ‘filename’, ‘data’, ‘description’ ]

INDEXED_FIELDS = [ ‘filename’ ]

BASE64_FIELDS = [‘data’]

In the “data” field you can dump file contents, like an mp3 or a jpeg, and IndexedRedis will handle all the encoding for you. You will just provide “bytes” data to that field.

Changes

See Changelog for list of changes.

Example

See This Example for a working example.

Contact Me

Please e-mail me with any questions, bugs, or even just to tell me that you’re using it! kata198@gmail.com