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602 lines
17 KiB
Markdown
602 lines
17 KiB
Markdown
---
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title: 请求响应转换
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keywords: [higress,transformer]
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description: 请求响应转换插件配置参考
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---
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## 功能说明
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`transformer` 插件可以对请求/响应头、请求查询参数、请求/响应体参数进行转换，支持的转换操作类型包括删除、重命名、更新、添加、追加、映射、去重。
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## 运行属性
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插件执行阶段：`认证阶段`
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插件执行优先级：`410`
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## 配置字段
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| 名称 | 数据类型 | 填写要求 | 默认值 | 描述 |
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| :----: | :----: | :----: | :----: | -------- |
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| reqRules | string | 选填，reqRules和respRules至少填一个 | - | 请求转换器配置，指定转换操作类型以及请求头、请求查询参数、请求体的转换规则 |
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| respRules | string | 选填，reqRules和respRules至少填一个 | - | 响应转换器配置，指定转换操作类型以及响应头、响应体的转换规则 |
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`reqRules`和`respRules`中每一项的配置字段说明如下：
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| 名称 | 数据类型 | 填写要求 | 默认值 | 描述 |
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| :----: | :----: | :----: | :----: | -------- |
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| operate | string | 必填，可选值为 `remove`, `rename`, `replace`, `add`, `append`, `map`, `dedupe` | - | 指定转换操作类型，支持的操作类型有删除 (remove)、重命名 (rename)、更新 (replace)、添加 (add)、追加 (append)、映射 (map)、去重 (dedupe)，当存在多项不同类型的转换规则时，按照上述操作类型顺序依次执行 |
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| mapSource | string | 选填，可选值为`headers`, `querys`,`body` | - | 仅在operate为`map`时有效。指定映射来源，若不填该字段，则默认映射来源为自身 |
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| headers | array of object | 选填 | - | 指定请求/响应头转换规则 |
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| querys | array of object | 选填 | - | 指定请求查询参数转换规则 |
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| body | array of object | 选填 | - | 指定请求/响应体参数转换规则，请求体转换允许 content-type 为 `application/json`, `application/x-www-form-urlencoded`, `multipart/form-data`；响应体转换仅允许 content-type 为 `application/json` |
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`headers`, `querys`, `body`中每一项的配置字段说明如下：
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| 名称 | 数据类型 | 填写要求 | 默认值 | 描述 |
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| :----: | :----: | :----: | -------- |---------------------------------------------------|
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| key | string | 选填 | - | 在operate为`remove`时使用，用法详见[转换操作类型](#转换操作类型) |
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| oldKey | string | 选填 | - |在operate为`rename`时使用，用法详见[转换操作类型](#转换操作类型) |
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| newKey | string | 选填 | - | 在operate为`rename`时使用，用法详见[转换操作类型](#转换操作类型) |
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| key | string | 选填 | - | 在operate为`replace`时使用，用法详见[转换操作类型](#转换操作类型) |
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| newValue | string | 选填 | - | 在operate为`replace`时使用，用法详见[转换操作类型](#转换操作类型) |
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| key | string | 选填 | - | 在operate为`add`时使用，用法详见[转换操作类型](#转换操作类型) |
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| value | string | 选填 | - | 在operate为`add`时使用，用法详见[转换操作类型](#转换操作类型) |
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| key | string | 选填 | - | 在operate为`append`时使用，用法详见[转换操作类型](#转换操作类型) |
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| appendValue | string | 选填 | - | 在operate为`append`时使用，用法详见[转换操作类型](#转换操作类型) |
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| fromKey | string | 选填 | - | 在operate为`map`时使用，用法详见[转换操作类型](#转换操作类型) |
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| toKey | string | 选填 | - | 在operate为`map`时使用，用法详见[转换操作类型](#转换操作类型) |
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| key | string | 选填 | - | 在operate为`dedupe`时使用，用法详见[转换操作类型](#转换操作类型) |
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| strategy | string | 选填 | - | 在operate为`dedupe`时使用，用法详见[转换操作类型](#转换操作类型) |
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| value_type | string | 选填，可选值为 `object`, `boolean`, `number`, `string` | string | 当`content-type: application/json`时，该字段指定请求/响应体参数的值类型 |
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| host_pattern | string | 选填 | - | 指定请求主机名匹配规则，当转换操作类型为 `replace`, `add`, `append` 时有效 |
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| path_pattern | string | 选填 | - | 指定请求路径匹配规则，当转换操作类型为 `replace`, `add`, `append` 时有效 |
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注意：
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* `request transformer` 支持以下转换对象：请求头部、请求查询参数、请求体（application/json, application/x-www-form-urlencoded, multipart/form-data）
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* `response transformer` 支持以下转换对象：响应头部、响应体（application/json）
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* 插件支持双向转换能力，即单个插件能够完成对请求和响应都做转换
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* 转换操作类型的执行顺序，为配置文件中编写的顺序，如：remove → rename → replace → add → append → map → dedupe或者dedupe → map → append → add → replace → rename → remove等
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* 当转换对象为 headers 时，` key` 不区分大小写；当为 headers 且为 `rename`, `map` 操作时，`value` 也不区分大小写（因为此时该字段具有 key 含义）；而 querys 和 body 的 `key`, `value` 字段均区分大小写
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* `value_type` 仅对 content-type 为 application/json 的请求/响应体有效
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* `host_pattern` 和 `path_pathern` 支持 [RE2 语法](https://pkg.go.dev/regexp/syntax)，仅对 `replace`, `add`, `append` 操作有效，且在一项转换规则中两者只能选填其一，若均填写，则 `host_pattern` 生效，而 `path_pattern` 失效
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## 转换操作类型
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| 操作类型 | key 字段含义 | value 字段含义 | 描述 |
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| :----: | :----: | :----: | ------------------------------------------------------------ |
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| 删除 remove | 目标 key |无需设置| 若存在指定的 `key`，则删除；否则无操作 |
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| 重命名 rename | 目标 oldKey |新的 key 名称 newKey| 若存在指定的 `oldKey:value`，则将其键名重命名为 `newKey`，得到 `newKey:value`；否则无操作 |
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| 更新 replace | 目标 key |新的 value 值 newValue| 若存在指定的 `key:value`，则将其 value 更新为 `newValue`，得到 `key:newValue`；否则无操作 |
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| 添加 add | 添加的 key | 添加的 value |若不存在指定的 `key:value`，则添加；否则无操作 |
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| 追加 append | 目标 key |追加的 value值 appendValue| 若存在指定的 `key:value`，则追加 appendValue 得到 `key:[value..., appendValue]`；否则相当于执行 add 操作，得到 `key:appendValue` |
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| 映射 map | 映射来源 fromKey |映射目标 toKey| 若存在指定的 `fromKey:fromValue`，则将其值 fromValue 映射给 toKey 的值，得到 `toKey:fromValue`，同时保留 `fromKey:fromValue`（注：若 toKey 已存在则其值会被覆盖）；否则无操作 |
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| 去重 dedupe | 目标 key |指定去重策略 strategy| `strategy` 可选值为：<br>`RETAIN_UNIQUE`: 按顺序保留所有唯一值，如 `k1:[v1,v2,v3,v3,v2,v1]`，去重后得到 `k1:[v1,v2,v3]` <br>`RETAIN_LAST`: 保留最后一个值，如 `k1:[v1,v2,v3]`，去重后得到 `k1:v3` <br>`RETAIN_FIRST` (default): 保留第一个值，如 `k1:[v1,v2,v3]`，去重后得到 `k1:v1`<br>（注：若去重后只剩下一个元素 v1 时，键值对变为 `k1:v1`, 而不是 `k1:[v1]`） |
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## 配置示例
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### 实现基于Body参数路由
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配置示例：
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```yaml
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reqRules:
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- operate: map
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headers:
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- fromKey: userId
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toKey: x-user-id
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mapSource: body
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```
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此规则将请求body中的`userId`解析出后，设置到请求Header`x-user-id`中，这样就可以基于Higress请求Header匹配路由的能力来实现基于Body参数的路由了。
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此配置同时支持`application/json`和`application/x-www-form-urlencoded`两种类型的请求Body。
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举例来说：
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**对于application/json类型的body**
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```bash
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curl localhost -d '{"userId":12, "userName":"johnlanni"}' -H 'content-type:application/json'
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```
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将从json中提取出`userId`字段的值，设置到`x-user-id`中，后端服务收到的请求头将增加:`x-usr-id: 12`。
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因为在插件新增这个Header后，网关将重新计算路由，所以可以实现网关路由配置根据这个请求头来匹配路由到特定的目标服务。
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**对于application/x-www-form-urlencoded类型的body**
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```bash
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curl localhost -d 'userId=12&userName=johnlanni'
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```
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将从`k1=v1&k2=v2`这样的表单格式中提取出`userId`字段的值，设置到`x-user-id`中，后端服务收到的请求头将增加:`x-usr-id: 12`。
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因为在插件新增这个Header后，网关将重新计算路由，所以可以实现网关路由配置根据这个请求头来匹配路由到特定的目标服务。
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#### json path 支持
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可以根据 [GJSON Path 语法](https://github.com/tidwall/gjson/blob/master/SYNTAX.md)，从复杂的 json 中提取出字段。
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比较常用的操作举例，对于以下 json:
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```json
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{
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"name": {"first": "Tom", "last": "Anderson"},
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"age":37,
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"children": ["Sara","Alex","Jack"],
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"fav.movie": "Deer Hunter",
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"friends": [
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{"first": "Dale", "last": "Murphy", "age": 44, "nets": ["ig", "fb", "tw"]},
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{"first": "Roger", "last": "Craig", "age": 68, "nets": ["fb", "tw"]},
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{"first": "Jane", "last": "Murphy", "age": 47, "nets": ["ig", "tw"]}
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]
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}
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```
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可以实现这样的提取:
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```text
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name.last "Anderson"
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name.first "Tom"
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age 37
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children ["Sara","Alex","Jack"]
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children.0 "Sara"
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children.1 "Alex"
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friends.1 {"first": "Roger", "last": "Craig", "age": 68}
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friends.1.first "Roger"
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```
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现在如果想从上面这个 json 格式的 body 中提取出 friends 中第二项的 first 字段，来设置到 Header `x-first-name` 中，同时抽取 last 字段，来设置到 Header `x-last-name` 中，则可以使用这份插件配置:
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```yaml
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reqRules:
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- operate: map
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headers:
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- fromKey: friends.1.first
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toKey: x-first-name
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- fromKey: friends.1.last
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toKey: x-last-name
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mapSource: body
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```
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### Request Transformer
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#### 转换请求头部
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```yaml
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reqRules:
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- operate: remove
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headers:
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- key: X-remove
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- operate: rename
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headers:
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- oldKey: X-not-renamed
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newKey: X-renamed
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- operate: replace
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headers:
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- key: X-replace
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newValue: replaced
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- operate: add
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headers:
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- key: X-add-append
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value: host-$1
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host_pattern: ^(.*)\.com$
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- operate: append
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headers:
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- key: X-add-append
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appendValue: path-$1
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path_pattern: ^.*?\/(\w+)[\?]{0,1}.*$
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- operate: map
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headers:
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- fromKey: X-add-append
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toKey: X-map
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- operate: dedupe
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headers:
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- key: X-dedupe-first
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strategy: RETAIN_FIRST
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- key: X-dedupe-last
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strategy: RETAIN_LAST
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- key: X-dedupe-unique
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strategy: RETAIN_UNIQUE
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```
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发送请求
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```bash
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$ curl -v console.higress.io/get -H 'host: foo.bar.com' \
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-H 'X-remove: exist' -H 'X-not-renamed:test' -H 'X-replace:not-replaced' \
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-H 'X-dedupe-first:1' -H 'X-dedupe-first:2' -H 'X-dedupe-first:3' \
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-H 'X-dedupe-last:a' -H 'X-dedupe-last:b' -H 'X-dedupe-last:c' \
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-H 'X-dedupe-unique:1' -H 'X-dedupe-unique:2' -H 'X-dedupe-unique:3' \
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-H 'X-dedupe-unique:3' -H 'X-dedupe-unique:2' -H 'X-dedupe-unique:1'
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# httpbin 响应结果
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{
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"args": {},
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"headers": {
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...
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"X-Add-Append": "host-foo.bar,path-get",
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...
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"X-Dedupe-First": "1",
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"X-Dedupe-Last": "c",
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"X-Dedupe-Unique": "1,2,3",
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...
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"X-Map": "host-foo.bar,path-get",
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"X-Renamed": "test",
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"X-Replace": "replaced"
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},
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...
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}
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```
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#### 转换请求查询参数
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```yaml
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reqRules:
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- operate: remove
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querys:
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- key: k1
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- operate: rename
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querys:
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- oldKey: k2
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newKey: k2-new
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- operate: replace
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querys:
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- key: k2-new
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newValue: v2-new
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- operate: add
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querys:
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- key: k3
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value: v31-$1
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path_pattern: ^.*?\/(\w+)[\?]{0,1}.*$
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- operate: append
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querys:
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- key: k3
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appendValue: v32
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- operate: map
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querys:
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- fromKey: k3
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toKey: k4
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- operate: dedupe
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querys:
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- key: k4
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strategy: RETAIN_FIRST
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```
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发送请求
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```bash
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$ curl -v "console.higress.io/get?k1=v11&k1=v12&k2=v2"
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# httpbin 响应结果
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{
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"args": {
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"k2-new": "v2-new",
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"k3": [
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"v31-get",
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"v32"
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],
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"k4": "v31-get"
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},
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...
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"url": "http://foo.bar.com/get?k2-new=v2-new&k3=v31-get&k3=v32&k4=v31-get"
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}
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```
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#### 转换请求体
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```yaml
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reqRules:
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- operate: remove
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body:
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- key: a1
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- operate: rename
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body:
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- oldKey: a2
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newKey: a2-new
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- operate: replace
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body:
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- key: a3
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newValue: t3-new
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value_type: string
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- operate: add
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body:
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- key: a1-new
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value: t1-new
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value_type: string
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- operate: append
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body:
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- key: a1-new
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appendValue: t1-$1-append
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value_type: string
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host_pattern: ^(.*)\.com$
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- operate: map
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body:
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- fromKey: a1-new
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toKey: a4
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- operate: dedupe
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body:
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- key: a4
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strategy: RETAIN_FIRST
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```
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发送请求：
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**1. Content-Type: application/json**
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```bash
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$ curl -v -x POST console.higress.io/post -H 'host: foo.bar.com' \
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-H 'Content-Type: application/json' -d '{"a1":"t1","a2":"t2","a3":"t3"}'
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# httpbin 响应结果
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{
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...
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"headers": {
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...
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"Content-Type": "application/json",
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...
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},
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"json": {
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"a1-new": [
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"t1-new",
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"t1-foo.bar-append"
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],
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"a2-new": "t2",
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"a3": "t3-new",
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"a4": "t1-new"
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},
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...
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}
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```
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**2. Content-Type: application/x-www-form-urlencoded**
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```bash
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$ curl -v -X POST console.higress.io/post -H 'host: foo.bar.com' \
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-d 'a1=t1&a2=t2&a3=t3'
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# httpbin 响应结果
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{
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...
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"form": {
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"a1-new": [
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"t1-new",
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"t1-foo.bar-append"
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],
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"a2-new": "t2",
|
||
"a3": "t3-new",
|
||
"a4": "t1-new"
|
||
},
|
||
"headers": {
|
||
...
|
||
"Content-Type": "application/x-www-form-urlencoded",
|
||
...
|
||
},
|
||
...
|
||
}
|
||
```
|
||
|
||
**3. Content-Type: multipart/form-data**
|
||
|
||
```bash
|
||
$ curl -v -X POST console.higress.io/post -H 'host: foo.bar.com' \
|
||
-F a1=t1 -F a2=t2 -F a3=t3
|
||
|
||
# httpbin 响应结果
|
||
{
|
||
...
|
||
"form": {
|
||
"a1-new": [
|
||
"t1-new",
|
||
"t1-foo.bar-append"
|
||
],
|
||
"a2-new": "t2",
|
||
"a3": "t3-new",
|
||
"a4": "t1-new"
|
||
},
|
||
"headers": {
|
||
...
|
||
"Content-Type": "multipart/form-data; boundary=------------------------1118b3fab5afbc4e",
|
||
...
|
||
},
|
||
...
|
||
}
|
||
```
|
||
|
||
### Response Transformer
|
||
|
||
与 Request Transformer 类似，在此仅说明转换 JSON 形式的请求/响应体时的注意事项：
|
||
|
||
#### key 嵌套 `.`
|
||
|
||
1.通常情况下，指定的 key 中含有 `.` 表示嵌套含义，如下：
|
||
|
||
```yaml
|
||
respRules:
|
||
- operate: add
|
||
body:
|
||
- key: foo.bar
|
||
value: value
|
||
```
|
||
|
||
```bash
|
||
$ curl -v console.higress.io/get
|
||
|
||
# httpbin 响应结果
|
||
{
|
||
...
|
||
"foo": {
|
||
"bar": "value"
|
||
},
|
||
...
|
||
}
|
||
```
|
||
|
||
2.当使用 `\.` 对 key 中的 `.` 进行转义后，表示非嵌套含义，如下：
|
||
|
||
> 当使用双引号括住字符串时使用 `\\.` 进行转义
|
||
|
||
```yaml
|
||
respRules:
|
||
- operate: add
|
||
body:
|
||
- key: foo\.bar
|
||
value: value
|
||
```
|
||
|
||
```bash
|
||
$ curl -v console.higress.io/get
|
||
|
||
# httpbin 响应结果
|
||
{
|
||
...
|
||
"foo.bar": "value",
|
||
...
|
||
}
|
||
```
|
||
|
||
#### 访问数组元素 `.index`
|
||
|
||
可以通过数组下标 `array.index 访问数组元素，下标从 0 开始：
|
||
|
||
```json
|
||
{
|
||
"users": [
|
||
{
|
||
"123": { "name": "zhangsan", "age": 18 }
|
||
},
|
||
{
|
||
"456": { "name": "lisi", "age": 19 }
|
||
}
|
||
]
|
||
}
|
||
```
|
||
|
||
1.移除 `user` 第一个元素：
|
||
|
||
```yaml
|
||
reqRules:
|
||
- operate: remove
|
||
body:
|
||
- key: users.0
|
||
```
|
||
|
||
```bash
|
||
$ curl -v -X POST console.higress.io/post \
|
||
-H 'Content-Type: application/json' \
|
||
-d '{"users":[{"123":{"name":"zhangsan"}},{"456":{"name":"lisi"}}]}'
|
||
|
||
# httpbin 响应结果
|
||
{
|
||
...
|
||
"json": {
|
||
"users": [
|
||
{
|
||
"456": {
|
||
"name": "lisi"
|
||
}
|
||
}
|
||
]
|
||
},
|
||
...
|
||
}
|
||
```
|
||
|
||
2.将 `users` 第一个元素的 key 为 `123` 重命名为 `msg`:
|
||
|
||
```yaml
|
||
reqRules:
|
||
- operate: rename
|
||
body:
|
||
- oldKey: users.0.123
|
||
newKey: users.0.first
|
||
```
|
||
|
||
```bash
|
||
$ curl -v -X POST console.higress.io/post \
|
||
-H 'Content-Type: application/json' \
|
||
-d '{"users":[{"123":{"name":"zhangsan"}},{"456":{"name":"lisi"}}]}'
|
||
|
||
|
||
# httpbin 响应结果
|
||
{
|
||
...
|
||
"json": {
|
||
"users": [
|
||
{
|
||
"msg": {
|
||
"name": "zhangsan"
|
||
}
|
||
},
|
||
{
|
||
"456": {
|
||
"name": "lisi"
|
||
}
|
||
}
|
||
]
|
||
},
|
||
...
|
||
}
|
||
```
|
||
|
||
#### 遍历数组元素 `.#`
|
||
|
||
可以使用 `array.#` 对数组进行遍历操作：
|
||
|
||
> ❗️该操作目前只能用在 replace 上，请勿在其他转换中尝试该操作，以免造成无法预知的结果
|
||
|
||
```json
|
||
{
|
||
"users": [
|
||
{
|
||
"name": "zhangsan",
|
||
"age": 18
|
||
},
|
||
{
|
||
"name": "lisi",
|
||
"age": 19
|
||
}
|
||
]
|
||
}
|
||
```
|
||
|
||
```yaml
|
||
reqRules:
|
||
- operate: replace
|
||
body:
|
||
- key: users.#.age
|
||
newValue: 20
|
||
```
|
||
|
||
```bash
|
||
$ curl -v -X POST console.higress.io/post \
|
||
-H 'Content-Type: application/json' \
|
||
-d '{"users":[{"name":"zhangsan","age":18},{"name":"lisi","age":19}]}'
|
||
|
||
|
||
# httpbin 响应结果
|
||
{
|
||
...
|
||
"json": {
|
||
"users": [
|
||
{
|
||
"age": "20",
|
||
"name": "zhangsan"
|
||
},
|
||
{
|
||
"age": "20",
|
||
"name": "lisi"
|
||
}
|
||
]
|
||
},
|
||
...
|
||
}
|
||
```
|