`client`：向 Prisma 客户端添加方法

info

Prisma 客户端扩展从版本 4.16.0 及更高版本开始正式可用。它们是在 4.7.0 版本的预览版中引入的。如果你运行的版本早于 4.16.0，请确保启用 clientExtensions Preview 功能标志。

¥Prisma Client extensions are Generally Available from versions 4.16.0 and later. They were introduced in Preview in version 4.7.0. Make sure you enable the clientExtensions Preview feature flag if you are running on a version earlier than 4.16.0.

你可以使用 client Prisma 客户端扩展组件将顶层方法添加到 Prisma 客户端。

¥You can use the client Prisma Client extensions component to add top-level methods to Prisma Client.

扩展 Prisma 客户端

¥Extend Prisma Client

使用 $extends 客户级方法创建扩展客户端。扩展客户端是标准 Prisma 客户端的一种变体，由一个或多个扩展封装。使用 client 扩展组件向 Prisma 客户端添加顶层方法。

¥Use the $extends client-level method to create an extended client. An extended client is a variant of the standard Prisma Client that is wrapped by one or more extensions. Use the client extension component to add top-level methods to Prisma Client.

要将顶层方法添加到 Prisma Client，请使用以下结构：

¥To add a top-level method to Prisma Client, use the following structure:

const prisma = new PrismaClient().$extends({
  client?: { ... }
})

示例

¥Example

以下示例使用 client 组件向 Prisma Client 添加两个方法：

¥The following example uses the client component to add two methods to Prisma Client:

$log 输出一条消息。

¥$log outputs a message.
$totalQueries 返回当前客户端实例执行的查询数。它使用 metrics 功能来收集此信息。

¥$totalQueries returns the number of queries executed by the current client instance. It uses the metrics feature to collect this information.

info

要在项目中使用指标，你必须在 schema.prisma 文件的 generator 块中启用 metrics 功能标志。了解更多。

¥To use metrics in your project, you must enable the metrics feature flag in the generator block of your schema.prisma file. Learn more.

const prisma = new PrismaClient().$extends({
  client: {
    $log: (s: string) => console.log(s),
    async $totalQueries() {
      const index_prisma_client_queries_total = 0
      // Prisma.getExtensionContext(this) in the following block
      // returns the current client instance
      const metricsCounters = await (
        await Prisma.getExtensionContext(this).$metrics.json()
      ).counters

      return metricsCounters[index_prisma_client_queries_total].value
    },
  },
})

async function main() {
  prisma.$log('Hello world')
  const totalQueries = await prisma.$totalQueries()
  console.log(totalQueries)
}

扩展 Prisma 客户端​

示例​

扩展 Prisma 客户端

示例