convex-helpers-guide

Compare original and translation side by side

🇺🇸

Original

English

🇨🇳

Translation

Chinese

Convex Helpers Guide

Convex Helpers 使用指南

Use convex-helpers to add common patterns and utilities to your Convex backend without reinventing the wheel.

使用convex-helpers为你的Convex后端添加常见开发模式与工具，无需重复造轮子。

What is convex-helpers?

什么是convex-helpers？

convex-helpers

is the official collection of utilities that complement Convex. It provides battle-tested patterns for common backend needs.

Installation:

bash

npm install convex-helpers

convex-helpers

是Convex官方推出的配套工具集，为常见的后端开发需求提供经过实战验证的实现模式。

安装：

bash

npm install convex-helpers

Available Helpers

可用工具

1. Relationship Helpers

1. 关系处理工具

Traverse relationships between tables in a readable, type-safe way.

Use when:

Loading related data across tables
Following foreign key relationships
Building nested data structures

Example:

typescript

import { getOneFrom, getManyFrom } from "convex-helpers/server/relationships";

export const getTaskWithUser = query({
  args: { taskId: v.id("tasks") },
  handler: async (ctx, args) => {
    const task = await ctx.db.get(args.taskId);
    if (!task) return null;

    // Get related user
    const user = await getOneFrom(
      ctx.db,
      "users",
      "by_id",
      task.userId,
      "_id"
    );

    // Get related comments
    const comments = await getManyFrom(
      ctx.db,
      "comments",
      "by_task",
      task._id,
      "taskId"
    );

    return { ...task, user, comments };
  },
});

Key Functions:

```
getOneFrom
```
- Get single related document
```
getManyFrom
```
- Get multiple related documents
```
getManyVia
```
- Get many-to-many relationships through junction table

以可读、类型安全的方式遍历数据表之间的关联关系。

适用场景：

跨表加载关联数据
外键关系查询
构建嵌套数据结构

示例：

typescript

import { getOneFrom, getManyFrom } from "convex-helpers/server/relationships";

export const getTaskWithUser = query({
  args: { taskId: v.id("tasks") },
  handler: async (ctx, args) => {
    const task = await ctx.db.get(args.taskId);
    if (!task) return null;

    // 获取关联用户
    const user = await getOneFrom(
      ctx.db,
      "users",
      "by_id",
      task.userId,
      "_id"
    );

    // 获取关联评论
    const comments = await getManyFrom(
      ctx.db,
      "comments",
      "by_task",
      task._id,
      "taskId"
    );

    return { ...task, user, comments };
  },
});

核心函数：

```
getOneFrom
```
- 获取单个关联文档
```
getManyFrom
```
- 获取多个关联文档
```
getManyVia
```
- 通过中间表获取多对多关联关系

2. Custom Functions (Data Protection) - MOST IMPORTANT

2. 自定义函数（数据保护）—— 最重要

This is Convex's alternative to Row Level Security (RLS). Instead of database-level policies, use custom function wrappers to automatically add auth and access control to all queries and mutations.

Create wrapped versions of query/mutation/action with custom behavior.

Use when:

Data protection and access control (PRIMARY USE CASE)
Want to add auth logic to all functions
Multi-tenant applications
Role-based access control (RBAC)
Need to inject common data into ctx
Building internal-only functions
Adding logging/monitoring to all functions

Why this instead of RLS:

TypeScript, not SQL policies
Full type safety
Easy to test and debug
More flexible than database policies
Works across your entire backend

Example: Custom Query with Auto-Auth

typescript

// convex/lib/customFunctions.ts
import { customQuery } from "convex-helpers/server/customFunctions";
import { query } from "../_generated/server";

export const authenticatedQuery = customQuery(
  query,
  {
    args: {}, // No additional args required
    input: async (ctx, args) => {
      const identity = await ctx.auth.getUserIdentity();
      if (!identity) {
        throw new Error("Not authenticated");
      }

      const user = await ctx.db
        .query("users")
        .withIndex("by_token", q =>
          q.eq("tokenIdentifier", identity.tokenIdentifier)
        )
        .unique();

      if (!user) throw new Error("User not found");

      // Add user to context
      return { ctx: { ...ctx, user }, args };
    },
  }
);

// Usage in your functions
export const getMyTasks = authenticatedQuery({
  handler: async (ctx) => {
    // ctx.user is automatically available!
    return await ctx.db
      .query("tasks")
      .withIndex("by_user", q => q.eq("userId", ctx.user._id))
      .collect();
  },
});

Example: Multi-Tenant Data Protection

typescript

import { customQuery } from "convex-helpers/server/customFunctions";
import { query } from "../_generated/server";

// Organization-scoped query - automatic access control
export const orgQuery = customQuery(query, {
  args: { orgId: v.id("organizations") },
  input: async (ctx, args) => {
    const user = await getCurrentUser(ctx);

    // Verify user is a member of this organization
    const member = await ctx.db
      .query("organizationMembers")
      .withIndex("by_org_and_user", q =>
        q.eq("orgId", args.orgId).eq("userId", user._id)
      )
      .unique();

    if (!member) {
      throw new Error("Not authorized for this organization");
    }

    // Inject org context
    return {
      ctx: {
        ...ctx,
        user,
        orgId: args.orgId,
        role: member.role
      },
      args
    };
  },
});

// Usage - data automatically scoped to organization
export const getOrgProjects = orgQuery({
  args: { orgId: v.id("organizations") },
  handler: async (ctx) => {
    // ctx.user and ctx.orgId automatically available and verified!
    return await ctx.db
      .query("projects")
      .withIndex("by_org", q => q.eq("orgId", ctx.orgId))
      .collect();
  },
});

Example: Role-Based Access Control

typescript

import { customMutation } from "convex-helpers/server/customFunctions";
import { mutation } from "../_generated/server";

export const adminMutation = customMutation(mutation, {
  args: {},
  input: async (ctx, args) => {
    const user = await getCurrentUser(ctx);

    if (user.role !== "admin") {
      throw new Error("Admin access required");
    }

    return { ctx: { ...ctx, user }, args };
  },
});

// Usage - only admins can call this
export const deleteUser = adminMutation({
  args: { userId: v.id("users") },
  handler: async (ctx, args) => {
    // Only admins reach this code
    await ctx.db.delete(args.userId);
  },
});

这是Convex提供的行级安全（RLS）替代方案。 无需数据库级别的策略，使用自定义函数包装器即可为所有查询和变更操作自动添加认证与访问控制逻辑。

创建带有自定义行为的查询/变更/操作包装版本。

适用场景：

数据保护与访问控制（主要使用场景）
为所有函数添加认证逻辑
多租户应用
基于角色的访问控制（RBAC）
需要向ctx注入通用数据
构建内部专用函数
为所有函数添加日志/监控

为什么选择该方案而非RLS：

基于TypeScript而非SQL策略
完全的类型安全
易于测试与调试
比数据库策略更灵活
适用于整个后端

示例：带自动认证的自定义查询

typescript

// convex/lib/customFunctions.ts
import { customQuery } from "convex-helpers/server/customFunctions";
import { query } from "../_generated/server";

export const authenticatedQuery = customQuery(
  query,
  {
    args: {}, // 无需额外参数
    input: async (ctx, args) => {
      const identity = await ctx.auth.getUserIdentity();
      if (!identity) {
        throw new Error("未认证");
      }

      const user = await ctx.db
        .query("users")
        .withIndex("by_token", q =>
          q.eq("tokenIdentifier", identity.tokenIdentifier)
        )
        .unique();

      if (!user) throw new Error("用户未找到");

      // 将用户信息添加到上下文
      return { ctx: { ...ctx, user }, args };
    },
  }
);

// 在函数中使用
export const getMyTasks = authenticatedQuery({
  handler: async (ctx) => {
    // ctx.user 已自动可用！
    return await ctx.db
      .query("tasks")
      .withIndex("by_user", q => q.eq("userId", ctx.user._id))
      .collect();
  },
});

示例：多租户数据保护

typescript

import { customQuery } from "convex-helpers/server/customFunctions";
import { query } from "../_generated/server";

// 组织范围的查询——自动访问控制
export const orgQuery = customQuery(query, {
  args: { orgId: v.id("organizations") },
  input: async (ctx, args) => {
    const user = await getCurrentUser(ctx);

    // 验证用户是否为该组织成员
    const member = await ctx.db
      .query("organizationMembers")
      .withIndex("by_org_and_user", q =>
        q.eq("orgId", args.orgId).eq("userId", user._id)
      )
      .unique();

    if (!member) {
      throw new Error("无该组织访问权限");
    }

    // 注入组织上下文
    return {
      ctx: {
        ...ctx,
        user,
        orgId: args.orgId,
        role: member.role
      },
      args
    };
  },
});

// 使用方式——数据自动限定在组织范围内
export const getOrgProjects = orgQuery({
  args: { orgId: v.id("organizations") },
  handler: async (ctx) => {
    // ctx.user 和 ctx.orgId 已自动可用并验证通过！
    return await ctx.db
      .query("projects")
      .withIndex("by_org", q => q.eq("orgId", ctx.orgId))
      .collect();
  },
});

示例：基于角色的访问控制

typescript

import { customMutation } from "convex-helpers/server/customFunctions";
import { mutation } from "../_generated/server";

export const adminMutation = customMutation(mutation, {
  args: {},
  input: async (ctx, args) => {
    const user = await getCurrentUser(ctx);

    if (user.role !== "admin") {
      throw new Error("需要管理员权限");
    }

    return { ctx: { ...ctx, user }, args };
  },
});

// 使用方式——仅管理员可调用
export const deleteUser = adminMutation({
  args: { userId: v.id("users") },
  handler: async (ctx, args) => {
    // 只有管理员能执行到此处代码
    await ctx.db.delete(args.userId);
  },
});

3. Filter Helper

3. 过滤工具

Apply complex TypeScript filters to database queries.

Use when:

Need to filter by computed values
Filtering logic is too complex for indexes
Working with small result sets

Example:

typescript

import { filter } from "convex-helpers/server/filter";

export const getActiveTasks = query({
  handler: async (ctx) => {
    const now = Date.now();
    const threeDaysAgo = now - 3 * 24 * 60 * 60 * 1000;

    return await filter(
      ctx.db.query("tasks"),
      (task) =>
        !task.completed &&
        task.createdAt > threeDaysAgo &&
        task.priority === "high"
    ).collect();
  },
});

Note: Still prefer indexes when possible! Use filter for complex logic that can't be indexed.

将复杂的TypeScript过滤逻辑应用到数据库查询中。

适用场景：

需要根据计算值过滤数据
过滤逻辑过于复杂无法使用索引
处理小结果集

示例：

typescript

import { filter } from "convex-helpers/server/filter";

export const getActiveTasks = query({
  handler: async (ctx) => {
    const now = Date.now();
    const threeDaysAgo = now - 3 * 24 * 60 * 60 * 1000;

    return await filter(
      ctx.db.query("tasks"),
      (task) =>
        !task.completed &&
        task.createdAt > threeDaysAgo &&
        task.priority === "high"
    ).collect();
  },
});

注意： 仍优先使用索引！仅当无法通过索引实现复杂逻辑时再使用filter。

4. Sessions

4. 会话管理

Track users across requests even when not logged in.

Use when:

Need to track anonymous users
Building shopping cart for guests
Tracking user behavior before signup
A/B testing without auth

Setup:

typescript

// convex/sessions.ts
import { SessionIdArg } from "convex-helpers/server/sessions";
import { query } from "./_generated/server";

export const trackView = query({
  args: {
    ...SessionIdArg, // Adds sessionId: v.string()
    pageUrl: v.string(),
  },
  handler: async (ctx, args) => {
    await ctx.db.insert("pageViews", {
      sessionId: args.sessionId,
      pageUrl: args.pageUrl,
      timestamp: Date.now(),
    });
  },
});

Client (React):

typescript

import { useSessionId } from "convex-helpers/react/sessions";
import { useQuery } from "convex/react";
import { api } from "../convex/_generated/api";

function MyComponent() {
  const sessionId = useSessionId();

  // Automatically includes sessionId in all requests
  useQuery(api.sessions.trackView, {
    sessionId,
    pageUrl: window.location.href,
  });
}

即使在用户未登录的情况下，也能跨请求跟踪用户。

适用场景：

需要跟踪匿名用户
为访客构建购物车
跟踪用户注册前的行为
无需认证的A/B测试

设置：

typescript

// convex/sessions.ts
import { SessionIdArg } from "convex-helpers/server/sessions";
import { query } from "./_generated/server";

export const trackView = query({
  args: {
    ...SessionIdArg, // 添加 sessionId: v.string()
    pageUrl: v.string(),
  },
  handler: async (ctx, args) => {
    await ctx.db.insert("pageViews", {
      sessionId: args.sessionId,
      pageUrl: args.pageUrl,
      timestamp: Date.now(),
    });
  },
});

客户端（React）：

typescript

import { useSessionId } from "convex-helpers/react/sessions";
import { useQuery } from "convex/react";
import { api } from "../convex/_generated/api";

function MyComponent() {
  const sessionId = useSessionId();

  // 自动在所有请求中包含sessionId
  useQuery(api.sessions.trackView, {
    sessionId,
    pageUrl: window.location.href,
  });
}

5. Zod Validation

5. Zod 验证

Use Zod schemas instead of Convex validators.

Use when:

Already using Zod in your project
Want more complex validation logic
Need custom error messages

Example:

typescript

import { zCustomQuery } from "convex-helpers/server/zod";
import { z } from "zod";
import { query } from "./_generated/server";

const argsSchema = z.object({
  email: z.string().email(),
  age: z.number().min(18).max(120),
});

export const createUser = zCustomQuery(query, {
  args: argsSchema,
  handler: async (ctx, args) => {
    // args is typed from Zod schema
    return await ctx.db.insert("users", args);
  },
});

使用Zod模式替代Convex内置验证器。

适用场景：

项目中已使用Zod
需要更复杂的验证逻辑
需要自定义错误提示

示例：

typescript

import { zCustomQuery } from "convex-helpers/server/zod";
import { z } from "zod";
import { query } from "./_generated/server";

const argsSchema = z.object({
  email: z.string().email(),
  age: z.number().min(18).max(120),
});

export const createUser = zCustomQuery(query, {
  args: argsSchema,
  handler: async (ctx, args) => {
    // args 类型由Zod模式自动推导
    return await ctx.db.insert("users", args);
  },
});

6. Alternative: Row-Level Security Helper

6. 替代方案：行级安全工具

Note: Convex recommends using custom functions (see #2 above) as the primary data protection pattern. This RLS helper is an alternative approach that mimics traditional RLS.

However, custom functions are usually better because:

Type-safe at compile time (RLS is runtime)
More explicit (easy to see what auth is applied)
Better error messages
Easier to test

注意： Convex推荐使用自定义函数（见上文第2部分）作为主要的数据保护模式。该RLS工具是模仿传统RLS的替代方案。

但自定义函数通常更优，因为：

编译时类型安全（RLS为运行时）
更明确（易于查看应用的认证逻辑）
错误提示更友好
更易于测试

7. Migrations

7. 数据迁移

Run data migrations safely.

Use when:

Backfilling new fields
Transforming existing data
Moving between schema versions

Example:

typescript

import { makeMigration } from "convex-helpers/server/migrations";

export const addDefaultPriority = makeMigration({
  table: "tasks",
  migrateOne: async (ctx, doc) => {
    if (doc.priority === undefined) {
      await ctx.db.patch(doc._id, { priority: "medium" });
    }
  },
});

// Run: npx convex run migrations:addDefaultPriority

安全地执行数据迁移。

适用场景：

回填新字段
转换现有数据
不同版本 schema 之间的迁移

示例：

typescript

import { makeMigration } from "convex-helpers/server/migrations";

export const addDefaultPriority = makeMigration({
  table: "tasks",
  migrateOne: async (ctx, doc) => {
    if (doc.priority === undefined) {
      await ctx.db.patch(doc._id, { priority: "medium" });
    }
  },
});

// 运行：npx convex run migrations:addDefaultPriority

8. Triggers

8. 触发器

Execute code automatically when data changes.

Use when:

Sending notifications on data changes
Updating related records
Logging changes
Maintaining computed fields

Example:

typescript

import { Triggers } from "convex-helpers/server/triggers";

const triggers = new Triggers();

triggers.register("tasks", "insert", async (ctx, task) => {
  // Send notification when task is created
  await ctx.db.insert("notifications", {
    userId: task.userId,
    type: "task_created",
    taskId: task._id,
  });
});

当数据发生变化时自动执行代码。

适用场景：

数据变化时发送通知
更新关联记录
记录变更日志
维护计算字段

示例：

typescript

import { Triggers } from "convex-helpers/server/triggers";

const triggers = new Triggers();

triggers.register("tasks", "insert", async (ctx, task) => {
  // 任务创建时发送通知
  await ctx.db.insert("notifications", {
    userId: task.userId,
    type: "task_created",
    taskId: task._id,
  });
});

Common Patterns

常见模式

Pattern 1: Authenticated Queries with User Context

模式1：带用户上下文的认证查询

typescript

import { customQuery } from "convex-helpers/server/customFunctions";

export const authedQuery = customQuery(query, {
  args: {},
  input: async (ctx, args) => {
    const user = await getCurrentUser(ctx);
    return { ctx: { ...ctx, user }, args };
  },
});

// Now all queries automatically have user in context
export const getMyData = authedQuery({
  handler: async (ctx) => {
    // ctx.user is typed and available!
    return await ctx.db
      .query("data")
      .withIndex("by_user", q => q.eq("userId", ctx.user._id))
      .collect();
  },
});

typescript

import { customQuery } from "convex-helpers/server/customFunctions";

export const authedQuery = customQuery(query, {
  args: {},
  input: async (ctx, args) => {
    const user = await getCurrentUser(ctx);
    return { ctx: { ...ctx, user }, args };
  },
});

// 现在所有查询自动包含用户上下文
export const getMyData = authedQuery({
  handler: async (ctx) => {
    // ctx.user 已自动推导类型并可用！
    return await ctx.db
      .query("data")
      .withIndex("by_user", q => q.eq("userId", ctx.user._id))
      .collect();
  },
});

Pattern 2: Loading Related Data

模式2：加载关联数据

typescript

import { getOneFrom, getManyFrom } from "convex-helpers/server/relationships";

export const getPostWithDetails = query({
  args: { postId: v.id("posts") },
  handler: async (ctx, args) => {
    const post = await ctx.db.get(args.postId);
    if (!post) return null;

    const author = await getOneFrom(ctx.db, "users", "by_id", post.authorId, "_id");
    const comments = await getManyFrom(ctx.db, "comments", "by_post", post._id, "postId");

    const tagLinks = await getManyFrom(ctx.db, "postTags", "by_post", post._id, "postId");
    const tags = await Promise.all(
      tagLinks.map(link =>
        getOneFrom(ctx.db, "tags", "by_id", link.tagId, "_id")
      )
    );

    return { ...post, author, comments, tags };
  },
});

typescript

import { getOneFrom, getManyFrom } from "convex-helpers/server/relationships";

export const getPostWithDetails = query({
  args: { postId: v.id("posts") },
  handler: async (ctx, args) => {
    const post = await ctx.db.get(args.postId);
    if (!post) return null;

    const author = await getOneFrom(ctx.db, "users", "by_id", post.authorId, "_id");
    const comments = await getManyFrom(ctx.db, "comments", "by_post", post._id, "postId");

    const tagLinks = await getManyFrom(ctx.db, "postTags", "by_post", post._id, "postId");
    const tags = await Promise.all(
      tagLinks.map(link =>
        getOneFrom(ctx.db, "tags", "by_id", link.tagId, "_id")
      )
    );

    return { ...post, author, comments, tags };
  },
});

Pattern 3: Batch Operations with Error Handling

模式3：带错误处理的批量操作

typescript

import { asyncMap } from "convex-helpers";

export const batchUpdateTasks = mutation({
  args: {
    taskIds: v.array(v.id("tasks")),
    status: v.string(),
  },
  handler: async (ctx, args) => {
    const results = await asyncMap(args.taskIds, async (taskId) => {
      try {
        const task = await ctx.db.get(taskId);
        if (task) {
          await ctx.db.patch(taskId, { status: args.status });
          return { success: true, taskId };
        }
        return { success: false, taskId, error: "Not found" };
      } catch (error) {
        return { success: false, taskId, error: error.message };
      }
    });

    return results;
  },
});

typescript

import { asyncMap } from "convex-helpers";

export const batchUpdateTasks = mutation({
  args: {
    taskIds: v.array(v.id("tasks")),
    status: v.string(),
  },
  handler: async (ctx, args) => {
    const results = await asyncMap(args.taskIds, async (taskId) => {
      try {
        const task = await ctx.db.get(taskId);
        if (task) {
          await ctx.db.patch(taskId, { status: args.status });
          return { success: true, taskId };
        }
        return { success: false, taskId, error: "未找到" };
      } catch (error) {
        return { success: false, taskId, error: error.message };
      }
    });

    return results;
  },
});

When to Use What

工具选择指南

Need	Use	Import From
Load related data	`getOneFrom` , `getManyFrom`	`convex-helpers/server/relationships`
Auth in all functions	`customQuery`	`convex-helpers/server/customFunctions`
Complex filters	`filter`	`convex-helpers/server/filter`
Anonymous users	`useSessionId`	`convex-helpers/react/sessions`
Zod validation	`zCustomQuery`	`convex-helpers/server/zod`
Data migrations	`makeMigration`	`convex-helpers/server/migrations`
Triggers	`Triggers`	`convex-helpers/server/triggers`

需求	使用工具	导入路径
加载关联数据	`getOneFrom` , `getManyFrom`	`convex-helpers/server/relationships`
为所有函数添加认证	`customQuery`	`convex-helpers/server/customFunctions`
复杂过滤逻辑	`filter`	`convex-helpers/server/filter`
匿名用户跟踪	`useSessionId`	`convex-helpers/react/sessions`
Zod 验证	`zCustomQuery`	`convex-helpers/server/zod`
数据迁移	`makeMigration`	`convex-helpers/server/migrations`
触发器	`Triggers`	`convex-helpers/server/triggers`

Checklist

检查清单

Installed convex-helpers:
```
npm install convex-helpers
```
Using relationship helpers for related data
Created custom functions for common auth patterns
Using sessions for anonymous tracking (if needed)
Prefer indexes over filter when possible
Check convex-helpers docs for new utilities

已安装convex-helpers：
```
npm install convex-helpers
```
使用关系处理工具加载关联数据
为通用认证模式创建自定义函数
（如有需要）使用会话管理跟踪匿名用户
优先使用索引而非filter
查看convex-helpers文档获取新工具