Authentication: WeChat Mini Program
WeChat Mini Program authentication using CloudBase Auth
How to Use
See How to Use Prompts for detailed usage instructions.
Test Prompts
You can use the following prompts to test:
- "Help me implement WeChat mini program user login feature"
- "Create a mini program application that supports WeChat login"
Prompt
rule.md
## When to use this skill
Use this skill for **WeChat Mini Program (小程序) authentication** in a CloudBase project.
Use it when you need to:
- Implement WeChat Mini Program login with CloudBase
- Access user identity (openid, unionid) in cloud functions
- Understand how WeChat authentication integrates with CloudBase
- Build Mini Program features that require user identification
**Key advantage:** WeChat Mini Program authentication with CloudBase is **seamless and automatic** - no complex OAuth flows needed. When a Mini Program calls a cloud function, the user's `openid` is automatically injected and verified by WeChat.
**Do NOT use for:**
- Web-based WeChat login (use the **CloudBase Web Auth** skill at `skills/auth-web-skill`)
- Server-side auth with Node SDK (use the **CloudBase Node Auth** skill at `skills/auth-nodejs-skill`)
- Non-WeChat authentication methods (use appropriate auth skills)
---
## How to use this skill (for a coding agent)
1. **Confirm CloudBase environment**
- Ask the user for:
- `env` – CloudBase environment ID
- Confirm the Mini Program is linked to the CloudBase environment
2. **Understand the authentication flow**
- WeChat Mini Program authentication is **native and automatic**
- No explicit login API calls needed in most cases
- User identity is automatically available in cloud functions
- CloudBase handles all authentication verification
3. **Pick a scenario from this file**
- For basic user identity in cloud functions, use **Scenario 2**
- For Mini Program initialization, use **Scenario 1**
- For calling a cloud function from the Mini Program and receiving user identity, use **Scenario 3**
- For testing authentication, use **Scenario 4**
4. **Follow CloudBase API shapes exactly**
- Use `wx-server-sdk` in cloud functions
- Use `wx.cloud` in Mini Program client code
- Treat method names and parameter shapes in this file as canonical
5. **If you're unsure about an API**
- Consult the official CloudBase Mini Program documentation
- Only use methods that appear in official documentation
---
## Core concepts
### How WeChat Mini Program authentication works with CloudBase
1. **Automatic authentication:**
- When a Mini Program user calls a cloud function, WeChat automatically injects the user's identity
- No need for complex OAuth flows or token management
- CloudBase verifies the authenticity of the identity
2. **User identifiers:**
- `OPENID` – Unique identifier for the user in this specific Mini Program
- `APPID` – The Mini Program's App ID
- `UNIONID` – (Optional) Unique identifier across all apps under the same WeChat Open Platform account
- Only available when the Mini Program is bound to a WeChat Open Platform account
- Useful for identifying the same user across multiple Mini Programs or Official Accounts
3. **Security:**
- The `openid`, `appid`, and `unionid` are **verified and trustworthy**
- WeChat has already completed authentication
- Developers can directly use these identifiers without additional verification
4. **No explicit login required:**
- Users are automatically authenticated when they use the Mini Program
- No need to call login APIs in most cases
- Identity is available immediately in cloud functions
---
## Scenarios – WeChat Mini Program auth patterns
### Scenario 1: Initialize CloudBase in Mini Program
Use this in your Mini Program's `app.js` or entry point:
```js
// app.js
App({
onLaunch: function () {
// Initialize CloudBase
wx.cloud.init({
env: 'your-env-id', // Your CloudBase environment ID
traceUser: true // Optional: track user access in console
})
}
})
```
**Key points:**
- Call `wx.cloud.init()` once when the Mini Program launches
- Set `env` to your CloudBase environment ID
- `traceUser: true` enables user access tracking in CloudBase console (optional but recommended)
---
### Scenario 2: Get user identity in a cloud function
Use this when you need to know **who is calling** your cloud function:
```js
// Cloud function: cloudfunctions/getUserInfo/index.js
const cloud = require('wx-server-sdk')
// Initialize cloud with dynamic environment
cloud.init({
env: cloud.DYNAMIC_CURRENT_ENV
})
exports.main = async (event, context) => {
// Get user identity - this is automatically injected by WeChat
const { OPENID, APPID, UNIONID } = cloud.getWXContext()
console.log('User identity:', { OPENID, APPID, UNIONID })
// Use OPENID for user-specific operations
// For example: query user data, check permissions, etc.
return {
openid: OPENID,
appid: APPID,
unionid: UNIONID // May be undefined if not available
}
}
```
**Key points:**
- Use `cloud.getWXContext()` to get user identity
- `OPENID` is always available and uniquely identifies the user
- `APPID` identifies the Mini Program
- `UNIONID` is only available when:
- The Mini Program is bound to a WeChat Open Platform account
- The user has authorized the Mini Program
- These values are **verified and trustworthy** - no need to validate them
- Use `cloud.DYNAMIC_CURRENT_ENV` to automatically use the current environment
**Best practices:**
- Store `OPENID` in your database to associate data with users
- Use `OPENID` for authorization and access control
- Use `UNIONID` when you need to identify users across multiple Mini Programs or Official Accounts
- Never expose `OPENID` to other users (it's a private identifier)
---
### Scenario 3: Call cloud function from Mini Program
Use this in your Mini Program to call a cloud function and get user identity:
```js
// In Mini Program page
Page({
onLoad: function() {
this.getUserInfo()
},
getUserInfo: function() {
wx.cloud.callFunction({
name: 'getUserInfo', // Cloud function name
data: {}, // Optional parameters
success: res => {
console.log('User info from cloud function:', res.result)
// res.result contains { openid, appid, unionid }
// Use the user info
this.setData({
openid: res.result.openid
})
},
fail: err => {
console.error('Failed to get user info:', err)
}
})
}
})
```
**Key points:**
- Use `wx.cloud.callFunction()` to call cloud functions
- User identity is automatically passed to the cloud function
- No need to manually send user credentials
- Handle both success and error cases
---
### Scenario 4: Test authentication - Simple test function
**Cloud function (cloudfunctions/test/index.js):**
```js
const cloud = require('wx-server-sdk')
cloud.init({
env: cloud.DYNAMIC_CURRENT_ENV
})
exports.main = async (event, context) => {
// Get verified user identity - automatically injected by WeChat
const { OPENID, APPID, UNIONID } = cloud.getWXContext()
console.log('User identity:', { OPENID, APPID, UNIONID })
return {
success: true,
message: 'Authentication successful',
identity: {
openid: OPENID,
appid: APPID,
unionid: UNIONID || 'Not available'
},
timestamp: new Date().toISOString()
}
}
```
**Mini Program code:**
```js
// pages/index/index.js
Page({
data: {
userIdentity: null
},
onLoad: function() {
this.testAuth()
},
testAuth: function() {
console.log('Testing authentication...')
wx.cloud.callFunction({
name: 'test',
success: res => {
console.log('Authentication test result:', res.result)
this.setData({
userIdentity: res.result.identity
})
wx.showToast({
title: 'Auth successful',
icon: 'success'
})
},
fail: err => {
console.error('Authentication test failed:', err)
wx.showToast({
title: 'Auth failed',
icon: 'error'
})
}
})
}
})
```
**Key points:**
- No explicit login API call needed
- User identity is automatically available in cloud function
- `OPENID` is always present and verified
- `UNIONID` may be undefined if not available
- Use this pattern to verify authentication is working correctly
---
## Best practices
### 1. Always use cloud.DYNAMIC_CURRENT_ENV
```js
cloud.init({
env: cloud.DYNAMIC_CURRENT_ENV
})
```
This ensures the cloud function uses the correct environment automatically.
### 2. Store OPENID for user identification
- Use `OPENID` as the primary user identifier
- Store it in your database to associate data with users
- Never expose `OPENID` to other users
### 3. Handle UNIONID availability
```js
const { OPENID, UNIONID } = cloud.getWXContext()
if (UNIONID) {
// User has UNIONID - can be used for cross-app identification
console.log('UNIONID available:', UNIONID)
} else {
// UNIONID not available - use OPENID only
console.log('Using OPENID only:', OPENID)
}
```
### 4. Use OPENID for user-specific operations
- Use `OPENID` to identify and authorize users
- Store `OPENID` when you need to associate data with users
- Use `OPENID` in queries to ensure users only access their own data
### 5. Error handling
Always handle errors when calling cloud functions:
```js
wx.cloud.callFunction({
name: 'myFunction',
success: res => {
// Handle success
},
fail: err => {
console.error('Cloud function error:', err)
// Show user-friendly error message
wx.showToast({
title: 'Operation failed',
icon: 'error'
})
}
})
```
### 6. Initialize CloudBase early
Initialize CloudBase in `app.js` `onLaunch`:
```js
App({
onLaunch: function () {
wx.cloud.init({
env: 'your-env-id',
traceUser: true
})
}
})
```
---
## Common patterns
### Pattern 1: Get and return user identity
```js
const cloud = require('wx-server-sdk')
cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV })
exports.main = async (event, context) => {
const { OPENID, APPID, UNIONID } = cloud.getWXContext()
return {
openid: OPENID,
appid: APPID,
unionid: UNIONID || null
}
}
```
### Pattern 2: Use OPENID for authorization
```js
const cloud = require('wx-server-sdk')
cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV })
exports.main = async (event, context) => {
const { OPENID } = cloud.getWXContext()
// Check if user is authorized
if (OPENID === event.resourceOwnerId) {
// User is authorized to access this resource
return { authorized: true }
} else {
return { authorized: false, error: 'Unauthorized' }
}
}
```
### Pattern 3: Handle UNIONID availability
```js
const cloud = require('wx-server-sdk')
cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV })
exports.main = async (event, context) => {
const { OPENID, UNIONID } = cloud.getWXContext()
if (UNIONID) {
// Can use UNIONID for cross-app user identification
console.log('User has UNIONID:', UNIONID)
} else {
// Fall back to OPENID only
console.log('Using OPENID only:', OPENID)
}
return { openid: OPENID, hasUnionId: !!UNIONID }
}
```
---
## Summary
WeChat Mini Program authentication with CloudBase is **simple and secure**:
1. **No explicit login needed** - authentication is automatic
2. **User identity is verified** - `OPENID`, `APPID`, and `UNIONID` are trustworthy
3. **Easy to use** - just call `cloud.getWXContext()` in cloud functions
4. **Secure by default** - WeChat handles all authentication verification
**Key takeaways:**
- Initialize CloudBase with `wx.cloud.init()` in Mini Program
- Use `cloud.getWXContext()` to get user identity in cloud functions
- Use `OPENID` for user identification and authorization
- Handle `UNIONID` availability appropriately
- No explicit login API calls needed - authentication is automatic
For more complex authentication scenarios or integration with other systems, consider using CloudBase custom login in combination with WeChat authentication.