SQLite Cache

SQLite cache is a lightweight file caching solution provided by the JitStorage framework, implementing high-performance key-value cache services based on diskcache library and SQLite database. It provides zero-configuration deployment, cross-platform compatibility, and SQL query support, enabling complete caching functionality without additional database servers.

The hierarchical structure of SQLite cache elements is Meta (caches.Meta) → Type (caches.SqliteType) → Instance. Developers can quickly create SQLite cache instance elements through JitAi's visual development tools.

Of course, developers can also create their own Type elements or modify the official caches.SqliteType element provided by JitAi in their own App to implement their own encapsulation.

Quick Start

Creating Instance Elements

Directory Structure

Recommended Directory Structure

myapp/
└── caches/
    └── DefaultCache/
        ├── e.json
        └── DefaultCache.json

e.json File

Element Declaration File

{
  "backendBundleEntry": ".",
  "title": "Default Cache",
  "type": "caches.SqliteType"
}

Method Interfaces

Standard Cache Operations

Provides standard cache read/write and management methods.

Business Configuration File

DefaultCache.json

{
  "directory": "appData/caches/DefaultCache/sqlite.db"
}

Usage Example

Basic Usage Example

# Get cache instance
cache = app.getElement('caches.DefaultCache')

# Write to cache
cache.set('user:123', 'John Doe', 3600)

# Read from cache
user_name = cache.get('user:123')

# Delete cache
cache.delete('user:123')

Element Configuration

e.json Configuration

Property	Type	Required	Description
backendBundleEntry	str	Yes	Backend entry path, fixed as "."
title	str	Yes	Display title of cache element
type	str	Yes	Fixed as "caches.SqliteType"

Business Configuration File

Property	Type	Required	Description
directory	str	Yes	Storage path for SQLite database file, supports relative and absolute paths

Path Rules:

• Relative path: Relative to application root directory, e.g., appData/caches/cache.db
• Absolute path: Use complete file system path, e.g., /var/cache/myapp/cache.db

Methods

get

Get string value from cache.

Parameter Details

Parameter Name	Type	Corresponding Native Type	Required	Description
name	Stext	str	Yes	Cache key name

Return Value

str - Cached string value, returns None if not exists

Usage Example

Get Cache Value

cache = app.getElement('caches.DefaultCache')
value = cache.get('config:theme')
if value:
    print(f"Current theme: {value}")

set

Write data to cache, supporting strings, numbers, lists, dictionaries, and other data types.

Parameter Details

Parameter Name	Type	Corresponding Native Type	Required	Description
name	Stext	str	Yes	Cache key name
string	-	str/list/dict	Yes	Cache value, automatically serializes complex data types
ts	Numeric	int	No	Expiration time (seconds), None means never expires

Return Value

bool - Returns True on success, False on failure

Usage Example

Set Different Types of Cache Values

cache = app.getElement('caches.DefaultCache')

# String cache
cache.set('user:name', 'Alice', 3600)

# Dictionary cache
user_data = {'id': 123, 'name': 'Alice', 'role': 'admin'}
cache.set('user:data:123', user_data, 7200)

# List cache
cache.set('recent:orders', [1001, 1002, 1003], 1800)

delete

Delete specified cache item.

Parameter Details

Parameter Name	Type	Corresponding Native Type	Required	Description
name	Stext	str	Yes	Cache key name to delete

Return Value

bool - Returns True on successful deletion, also returns True if key doesn't exist

Usage Example

Delete Cache

cache = app.getElement('caches.DefaultCache')
success = cache.delete('temp:session:abc123')
print(f"Delete operation: {'Success' if success else 'Failed'}")

expire

Update cache item expiration time.

Parameter Details

Parameter Name	Type	Corresponding Native Type	Required	Description
name	Stext	str	Yes	Cache key name
ts	Numeric	int	Yes	New expiration time (seconds)

Return Value

bool - Returns True on success, False if key doesn't exist

Usage Example

Extend Cache Time

cache = app.getElement('caches.DefaultCache')
# Extend cache to expire after 1 hour
cache.expire('session:user123', 3600)

exists

Check if cache key exists.

Parameter Details

Parameter Name	Type	Corresponding Native Type	Required	Description
name	Stext	str	Yes	Cache key name to check

Return Value

bool - Returns True if exists, False if not

Usage Example

Check Cache Existence

cache = app.getElement('caches.DefaultCache')
if cache.exists('user:permission:123'):
    permissions = cache.get('user:permission:123')
else:
    # Reload permission data from database
    permissions = load_user_permissions(123)
    cache.set('user:permission:123', permissions, 1800)

incr

Atomically increment numeric type cache value.

Parameter Details

Parameter Name	Type	Corresponding Native Type	Required	Description
name	Stext	str	Yes	Cache key name
amount	Numeric	int	No	Increment value, defaults to 1

Return Value

int - New value after increment

Usage Example

Counter Operations

cache = app.getElement('caches.DefaultCache')

# Page view counting
views = cache.incr('page:views:home')
print(f"Home page views: {views}")

# Batch increment
cache.incr('api:calls:today', 10)

keys

Get all cache keys matching specified pattern.

Parameter Details

Parameter Name	Type	Corresponding Native Type	Required	Description
pattern	Stext	str	No	Match pattern, supports wildcards, defaults to "*"

Return Value

generator - Generator of matching key names

Usage Example

Batch Operations on Cache Keys

cache = app.getElement('caches.DefaultCache')

# Get all user cache keys
user_keys = list(cache.keys('user:*'))
print(f"User cache count: {len(user_keys)}")

# Clean up temporary cache
temp_keys = cache.keys('temp:*')
for key in temp_keys:
    cache.delete(key)

getNumeric

Get numeric type cache value.

Parameter Details

Parameter Name	Type	Corresponding Native Type	Required	Description
name	Stext	str	Yes	Cache key name

Return Value

int - Numeric result, returns 0 if not exists

Usage Example

Get Numeric Cache

cache = app.getElement('caches.DefaultCache')
count = cache.getNumeric('daily:login:count')
print(f"Today's login count: {count}")

setNumeric

Set numeric type cache value.

Parameter Details

Parameter Name	Type	Corresponding Native Type	Required	Description
name	Stext	str	Yes	Cache key name
n	Numeric	int	No	Numeric value, defaults to 0
ts	Numeric	int	No	Expiration time (seconds)

Return Value

bool - Returns True on success

Usage Example

Set Numeric Cache

cache = app.getElement('caches.DefaultCache')
cache.setNumeric('system:status', 1, 300)  # Expires in 5 minutes

Properties

None currently.

Advanced Features

Key Name Prefix Mechanism

SQLite cache automatically adds application ID prefix to all key names, ensuring cache isolation between different applications.

Key Name Prefix Example

# Actual stored key name format: {appId}:{name}
cache = app.getElement('caches.DefaultCache')
cache.set('user:123', 'data')  # Actually stored as "myapp:user:123"

Data Serialization Support

Automatically handles serialization and deserialization of complex data types.

Complex Data Type Caching

cache = app.getElement('caches.DefaultCache')

# Nested data structure
complex_data = {
    'users': [
        {'id': 1, 'name': 'Alice', 'roles': ['admin', 'user']},
        {'id': 2, 'name': 'Bob', 'roles': ['user']}
    ],
    'metadata': {
        'total': 2,
        'updated_at': '2024-01-15T10:30:00Z'
    }
}

cache.set('report:users', complex_data, 3600)
retrieved_data = cache.get('report:users')  # Automatically deserialized to original data structure

Automatic Cache Path Management

System automatically creates cache directories and initializes SQLite database files.

Multi-environment Cache Configuration

# Development environment
{
    "directory": "appData/caches/dev/cache.db"
}

# Production environment
{
    "directory": "/var/cache/myapp/prod.db"
}