# langmiddle
Middlewares for LangChain / LangGraph
[](https://github.com/alpha-xone/langmiddle/actions/workflows/ci.yml)
[](https://pypi.org/project/langmiddle/)
[](https://pypi.org/project/langmiddle/)
[](https://github.com/alpha-xone/langmiddle/blob/main/LICENSE)
## Overview
Production-ready middleware for **LangChain** and **LangGraph v1** with multi-backend chat history persistence. Store conversations in SQLite, Supabase, or Firebase with zero configuration required.
**Key Features:**
- ✅ **LangChain/LangGraph v1 Compatible**: Native middleware pattern support
- ⚡ **Zero Config Start**: Defaults to in-memory SQLite—no setup needed
- 🔄 **Multi-Backend Storage**: Switch between SQLite, PostgreSQL, Supabase, Firebase with one parameter
- 🔒 **Production Ready**: JWT authentication, RLS support, type-safe
## Available middleware
| Middleware | Description |
|---|---|
| ToolMessageRemover | Removes tool-related messages from the conversation state (pre/post agent). |
| ChatSaver | Persists chat history to configurable backends (SQLite, Postgres, Supabase, Firebase). |
## Installation
**Core Package** (SQLite only):
```bash
pip install langmiddle
```
**With Optional Backends:**
```bash
# For PostgreSQL support
pip install langmiddle[postgres]
# For Supabase support
pip install langmiddle[supabase]
# For Firebase support
pip install langmiddle[firebase]
# All backends
pip install langmiddle[all]
```
## Quick Start - LangChain Middleware
```python
from langmiddle.history import ChatSaver, ToolMessageRemover, StorageContext
# Initialize middleware with desired backend
agent = create_agent(
model="gpt-4o",
tools=[],
context_schema=StorageContext,
middleware=[
ToolMessageRemover(),
ChatSaver(backend="sqlite", db_path="./chat_history.db")
],
)
agent.invoke(
input={"messages": [{"role": "user", "content": "Hello!"}]},
context={
"user_id": "user-123",
"session_id": "session-123",
}
)
```
## Storage Backends
| Backend | Use Case | Pros | Cons | Setup |
|----------|----------|------|------|-------|
| **SQLite** | Development, Single-user | Simple, Local, Fast, No setup | Not distributed | None |
| **PostgreSQL** | Self-hosted, Custom auth | Full control, Standard SQL, Flexible | Manual setup | Connection string |
| **Supabase** | Production Web Apps | Managed PostgreSQL, RLS, Real-time | Supabase-specific | Environment vars |
| **Firebase** | Mobile, Google ecosystem | Real-time, Managed, Global | Google-specific | Service account |
### SQLite Configuration
```python
# Local file
backend_type="sqlite", db_path="./chat.db"
# In-memory (testing)
backend_type="sqlite", db_path=":memory:"
```
### PostgreSQL Configuration
```bash
# .env file or environment variables
POSTGRES_CONNECTION_STRING=postgresql://user:password@localhost:5432/dbname
```
```python
# Or pass directly
backend_type="postgres",
connection_string="postgresql://user:password@localhost:5432/dbname",
auto_create_tables=True
```
See [PostgreSQL Setup Guide](docs/POSTGRES_SETUP.md) for details.
### Supabase Configuration
```bash
# .env file or environment variables
SUPABASE_URL=your_supabase_url
SUPABASE_ANON_KEY=your_anon_key
```
### Firebase Configuration
```python
# Service account credentials file
backend_type="firebase", credentials_path="./firebase-creds.json"
# Or use GOOGLE_APPLICATION_CREDENTIALS environment variable
```
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"description": "# langmiddle\n\nMiddlewares for LangChain / LangGraph\n\n[](https://github.com/alpha-xone/langmiddle/actions/workflows/ci.yml)\n[](https://pypi.org/project/langmiddle/)\n[](https://pypi.org/project/langmiddle/)\n[](https://github.com/alpha-xone/langmiddle/blob/main/LICENSE)\n\n## Overview\n\nProduction-ready middleware for **LangChain** and **LangGraph v1** with multi-backend chat history persistence. Store conversations in SQLite, Supabase, or Firebase with zero configuration required.\n\n**Key Features:**\n- \u2705 **LangChain/LangGraph v1 Compatible**: Native middleware pattern support\n- \u26a1 **Zero Config Start**: Defaults to in-memory SQLite\u2014no setup needed\n- \ud83d\udd04 **Multi-Backend Storage**: Switch between SQLite, PostgreSQL, Supabase, Firebase with one parameter\n- \ud83d\udd12 **Production Ready**: JWT authentication, RLS support, type-safe\n\n## Available middleware\n\n| Middleware | Description |\n|---|---|\n| ToolMessageRemover | Removes tool-related messages from the conversation state (pre/post agent). |\n| ChatSaver | Persists chat history to configurable backends (SQLite, Postgres, Supabase, Firebase). |\n\n## Installation\n\n**Core Package** (SQLite only):\n```bash\npip install langmiddle\n```\n\n**With Optional Backends:**\n```bash\n# For PostgreSQL support\npip install langmiddle[postgres]\n\n# For Supabase support\npip install langmiddle[supabase]\n\n# For Firebase support\npip install langmiddle[firebase]\n\n# All backends\npip install langmiddle[all]\n```\n\n## Quick Start - LangChain Middleware\n\n```python\nfrom langmiddle.history import ChatSaver, ToolMessageRemover, StorageContext\n\n# Initialize middleware with desired backend\nagent = create_agent(\n model=\"gpt-4o\",\n tools=[],\n context_schema=StorageContext,\n middleware=[\n ToolMessageRemover(),\n ChatSaver(backend=\"sqlite\", db_path=\"./chat_history.db\")\n ],\n)\n\nagent.invoke(\n input={\"messages\": [{\"role\": \"user\", \"content\": \"Hello!\"}]},\n context={\n \"user_id\": \"user-123\",\n \"session_id\": \"session-123\",\n }\n)\n```\n\n## Storage Backends\n\n| Backend | Use Case | Pros | Cons | Setup |\n|----------|----------|------|------|-------|\n| **SQLite** | Development, Single-user | Simple, Local, Fast, No setup | Not distributed | None |\n| **PostgreSQL** | Self-hosted, Custom auth | Full control, Standard SQL, Flexible | Manual setup | Connection string |\n| **Supabase** | Production Web Apps | Managed PostgreSQL, RLS, Real-time | Supabase-specific | Environment vars |\n| **Firebase** | Mobile, Google ecosystem | Real-time, Managed, Global | Google-specific | Service account |\n\n### SQLite Configuration\n\n```python\n# Local file\nbackend_type=\"sqlite\", db_path=\"./chat.db\"\n\n# In-memory (testing)\nbackend_type=\"sqlite\", db_path=\":memory:\"\n```\n\n### PostgreSQL Configuration\n\n```bash\n# .env file or environment variables\nPOSTGRES_CONNECTION_STRING=postgresql://user:password@localhost:5432/dbname\n```\n\n```python\n# Or pass directly\nbackend_type=\"postgres\",\nconnection_string=\"postgresql://user:password@localhost:5432/dbname\",\nauto_create_tables=True\n```\n\nSee [PostgreSQL Setup Guide](docs/POSTGRES_SETUP.md) for details.\n\n### Supabase Configuration\n\n```bash\n# .env file or environment variables\nSUPABASE_URL=your_supabase_url\nSUPABASE_ANON_KEY=your_anon_key\n```\n\n### Firebase Configuration\n\n```python\n# Service account credentials file\nbackend_type=\"firebase\", credentials_path=\"./firebase-creds.json\"\n\n# Or use GOOGLE_APPLICATION_CREDENTIALS environment variable\n```\n",
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