# ngx\_stream\_js\_module

* [示例配置](/nginx-docs/he-xin-gong-neng/stream/ngx_stream_js_module.md#example_configuration)
* [指令](/nginx-docs/he-xin-gong-neng/stream/ngx_stream_js_module.md#directives)
  * [js\_access](/nginx-docs/he-xin-gong-neng/stream/ngx_stream_js_module.md#js_access)
  * [js\_filter](/nginx-docs/he-xin-gong-neng/stream/ngx_stream_js_module.md#js_filter)
  * [js\_include](/nginx-docs/he-xin-gong-neng/stream/ngx_stream_js_module.md#js_include)
  * [js\_preread](/nginx-docs/he-xin-gong-neng/stream/ngx_stream_js_module.md#js_preread)
  * [js\_set](/nginx-docs/he-xin-gong-neng/stream/ngx_stream_js_module.md#js_set)
* [会话对象属性](/nginx-docs/he-xin-gong-neng/stream/ngx_stream_js_module.md#properties)

`ngx_stream_js_module` 模块用于在 [njs](/nginx-docs/readme/guan-yu-nginscript.md) 中实现处理程序 —— 这是 JavaScript 语言的一个子集。

默认情况下不构建此模块。可在[此处](http://nginx.org/en/docs/njs/install.html)下载和安装说明。

> 此示例适用于 njs [0.2.4](http://nginx.org/en/docs/njs/changes.html#njs0.2.4) 及更高版本。对于 njs [0.2.3](http://nginx.org/en/docs/njs/changes.html#njs0.2.3) 及更早版本，请使用[此示例](http://nginx.org/en/docs/njs/examples.html#legacy)。

## 示例配置 <a href="#example_configuration" id="example_configuration"></a>

```
load_module modules/ngx_stream_js_module.so;
...

stream {
    js_include stream.js;

    js_set $bar bar;
    js_set $req_line req_line;

    server {
        listen 12345;

        js_preread preread;
        return     $req_line;
    }

    server {
        listen 12346;

        js_access  access;
        proxy_pass 127.0.0.1:8000;
        js_filter  header_inject;
    }
}

http {
    server {
        listen 8000;
        location / {
            return 200 $http_foo\n;
        }
    }
}
```

`stream.js` 内容：

```javascript
var line = '';

function bar(s) {
    var v = s.variables;
    s.log("hello from bar() handler!");
    return "bar-var" + v.remote_port + "; pid=" + v.pid;
}

function preread(s) {
    s.on('upload', function (data, flags) {
        var n = data.indexOf('\n');
        if (n != -1) {
            line = data.substr(0, n);
            s.done();
        }
    });
}

function req_line(s) {
    return line;
}

// Read HTTP request line.
// Collect bytes in 'req' until
// request line is read.
// Injects HTTP header into a client's request

var my_header =  'Foo: foo';
function header_inject(s) {
    var req = '';
    s.on('upload', function(data, flags) {
        req += data;
        var n = req.search('\n');
        if (n != -1) {
            var rest = req.substr(n + 1);
            req = req.substr(0, n + 1);
            s.send(req + my_header + '\r\n' + rest, flags);
            s.off('upload');
        }
    });
}

function access(s) {
    if (s.remoteAddress.match('^192.*')) {
        s.abort();
        return;
    }

    s.allow();
}
```

## 指令 <a href="#directives" id="directives"></a>

### js\_access

|       - | 说明                         |
| ------: | -------------------------- |
|  **语法** | **js\_access** `function`; |
|  **默认** | ——                         |
| **上下文** | stream、server              |

设置一个将在 [access](/nginx-docs/readme/nginx-ru-he-chu-li-tcpudp-hui-hua.md) 阶段调用的 njs 函数。

### js\_filter

|       - | 说明                         |
| ------: | -------------------------- |
|  **语法** | **js\_filter** `function`; |
|  **默认** | ——                         |
| **上下文** | stream、server              |

设置一个数据过滤器。

### js\_include

|       - | 说明                      |
| ------: | ----------------------- |
|  **语法** | **js\_include** `file`; |
|  **默认** | ——                      |
| **上下文** | stream                  |

指定一个使用 njs 实现服务器和变量处理程序的文件。

### js\_preread

|       - | 说明                          |
| ------: | --------------------------- |
|  **语法** | **js\_preread** `function`; |
|  **默认** | ——                          |
| **上下文** | stream、server               |

设置一个将在 \[preread]\((../../介绍/Nginx如何处理TCP\_UDP会话.md)) 阶段调用的 njs 函数。

### js\_set

|       - | 说明                      |
| ------: | ----------------------- |
|  **语法** | **js\_set** `function`; |
|  **默认** | ——                      |
| **上下文** | stream                  |

设置一个用于指定变量的 njs 函数。

## 会话对象属性 <a href="#properties" id="properties"></a>

每一个流 njs 处理程序都会接收一个参数，一个流会话[对象](http://nginx.org/en/docs/njs/reference.html#stream)。

## 原文档

<http://nginx.org/en/docs/stream/ngx_stream_js_module.html>


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