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# 目录
- [**简介**](#简介)
- [**属性**](#属性)
- [**如何启用**](#如何启用)
- [**测试插件**](#测试插件)
- [**禁用插件**](#禁用插件)

## 简介

echo 是一个有用的插件，可帮助用户尽可能全面地了解如何开发APISIX插件。


该插件展示了如何在常见的 phase 中实现相应的功能，常见的 phase 有：init, rewrite, access, balancer, header filer, body filter 以及 log。

## 属性

|属性名称          |必选项  |描述|
|---------     |--------|-----------|
| before_body |可选| 在 body 属性之前添加的内容，如果 body 属性没有指定将添加在 upstream response body 之前。 |
| body |可选| 返回给客户端的响应内容，它将覆盖 upstream 返回的响应 body。 |
| after_body |可选| 在 body 属性之后添加的内容，如果 body 属性没有指定将在 upstream 响应 body 之后添加。 |

## 如何启用

1. 为特定路由启用 echo 插件。

```shell
curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "plugins": {
        "echo": {
            "before_body": "before the body modification "
        }
    },
    "upstream": {
        "nodes": {
            "127.0.0.1:1980": 1
        },
        "type": "roundrobin"
    },
    "uri": "/hello"
}'
```

## 测试插件

* 成功:

```shell
$ curl -i http://127.0.0.1:9080/hello
HTTP/1.1 200 OK
...
before the body modification hello world
```

## 禁用插件

当您要禁用`echo`插件时，这很简单，您可以在插件配置中删除相应的json配置，无需重新启动服务，它将立即生效：

```shell
$ curl http://127.0.0.1:9080/apisix/admin/routes/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d value='
{
    "methods": ["GET"],
    "uri": "/hello",
    "plugins": {},
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:1980": 1
        }
    }
}'
```