法大大电子合同集成方案

注册流程（需要你操作）

- app_id

- app_secret

- open_corp_id

API对接架构

TopcentralMall ──→ 法大大API ──→ 客户签署
     │                │
     └─ 合同模板管理  └─ 签署状态回调

核心接口

费用预估（初创期）

按份计费：¥2-5/份
预估月合同量：10-50份
月费用：¥20-250
年费：¥0（无最低消费）

技术实现

# backend/app/services/fadada_service.py
import httpx
import hashlib
import time

class FaDaDaService:
    BASE_URL = "https://openapi.fadada.com/api/v5"
    
    def __init__(self, app_id: str, app_secret: str, open_corp_id: str):
        self.app_id = app_id
        self.app_secret = app_secret
        self.open_corp_id = open_corp_id
    
    def _sign(self, params: dict) -> str:
        """生成签名"""
        sorted_params = sorted(params.items())
        sign_str = "&".join(f"{k}={v}" for k, v in sorted_params)
        return hashlib.md5(f"{sign_str}{self.app_secret}".encode()).hexdigest()
    
    async def create_template(self, template_name: str, pdf_url: str):
        """创建合同模板"""
        params = {
            "appId": self.app_id,
            "timestamp": str(int(time.time())),
            "openCorpId": self.open_corp_id,
            "templateName": template_name,
            "file": pdf_url,
        }
        params["sign"] = self._sign(params)
        
        async with httpx.AsyncClient() as client:
            resp = await client.post(f"{self.BASE_URL}/template/create", json=params)
            return resp.json()
    
    async def initiate_sign(self, template_id: str, signers: list, contract_no: str):
        """发起签署任务"""
        params = {
            "appId": self.app_id,
            "timestamp": str(int(time.time())),
            "openCorpId": self.open_corp_id,
            "templateId": template_id,
            "signers": signers,
            "contractNo": contract_no,
        }
        params["sign"] = self._sign(params)
        
        async with httpx.AsyncClient() as client:
            resp = await client.post(f"{self.BASE_URL}/signTask/create", json=params)
            return resp.json()
    
    async def query_status(self, sign_task_id: str):
        """查询签署状态"""
        params = {
            "appId": self.app_id,
            "timestamp": str(int(time.time())),
            "openCorpId": self.open_corp_id,
            "signTaskId": sign_task_id,
        }
        params["sign"] = self._sign(params)
        
        async with httpx.AsyncClient() as client:
            resp = await client.get(f"{self.BASE_URL}/signTask/detail", params=params)
            return resp.json()
    
    async def download_contract(self, sign_task_id: str):
        """下载已签署合同"""
        params = {
            "appId": self.app_id,
            "timestamp": str(int(time.time())),
            "openCorpId": self.open_corp_id,
            "signTaskId": sign_task_id,
        }
        params["sign"] = self._sign(params)
        
        async with httpx.AsyncClient() as client:
            resp = await client.get(f"{self.BASE_URL}/signTask/download", params=params)
            return resp.content

数据库表设计

CREATE TABLE contracts (
    id SERIAL PRIMARY KEY,
    order_id INTEGER REFERENCES orders(id),
    contract_no VARCHAR(64) UNIQUE NOT NULL,
    template_id VARCHAR(64),
    sign_task_id VARCHAR(64),
    status VARCHAR(32) DEFAULT 'draft', -- draft/pending/signed/rejected/expired
    fadada_response JSONB,
    signed_at TIMESTAMP,
    created_at TIMESTAMP DEFAULT NOW(),
    updated_at TIMESTAMP DEFAULT NOW()
);

CREATE INDEX idx_contracts_order ON contracts(order_id);
CREATE INDEX idx_contracts_status ON contracts(status);

审批流触发规则

订单金额 ≥ ¥50,000 → 自动创建电子合同
                    → 发送给客户签署
                    → 签署完成 → 订单进入「待发货」
                    → 48h未签 → 催单Agent提醒

下一步

等你注册完法大大，把 app_id, app_secret, open_corp_id 发给我，我1天内完成API对接。