Summary of Methods and Properties of the HTTP Object in the Nginx JS Module

1. Summary of Methods and Properties of the HTTP Object in the JS Module

r.args

Request parameters, case-sensitive, read-only.
Values of repeated parameter names are converted to an array.
For example, 'a=1&b=2&A=3&b=4&B=two%20words' is converted to r.args, resulting in {a: "1", b: ["2", "4"], A: "3", B: "two words"}.

r.done()

After calling this function, the next data block will be returned directly to the client without invoking the js_body_filter function.

r.error(string)

Writes an error-level log to the error log.

r.finish()

Ends the response to the client.

r.headersIn

Gets the header values of the HTTP request, such as r.headersIn.Authorization.

r.headersOut

Header values of the HTTP response, which can be written to, such as r.headersOut["Content-Type"] = "text/plain".

r.httpVersion

HTTP version number, read-only.

r.internal

Value is true when the location is configured as internal.

r.internalRedirect(uri)

Performs an internal redirect, transparent to the client.

r.log(string)

Writes an info-level log to the error log.

r.method

Gets the HTTP request method, read-only.

r.parent

Parent request object.

r.remoteAddress

Client address, read-only.

r.requestBuffer

HTTP request body, can only be used in the js_content directive.

r.requestText

Same as r.requestBuffer, but returns a string.

r.rawHeadersIn

Array of key-value pairs of headers received from the client, with all field names in lowercase.

r.rawHeadersOut

Array of key-value pairs of HTTP response headers.

r.responseBuffer

Response body for the request.

r.responseText

Response body for the request, but returns a string.

r.return(status[, string | Buffer])

Returns a response to the client, with the first parameter as the status code and the second parameter as the response content string or buffer.

r.send(string | Buffer)

Sends response body content to the client, can send either a string or buffer.

r.sendBuffer(data[, options])

Can only be called by the js_body_filter method. Adds data to the data chain to be forwarded to the next filter. The first parameter data can be a string or buffer. The options object contains two fields: last and flush.
last: boolean type, true indicates that the current data is the last data block.
flush: boolean type, true indicates that the current data block should be a flush flag.

r.sendHeader()

Sends HTTP headers to the client.

r.setReturnValue(value)

Sets the return value obtained from the js_set directive, can only be used in asynchronous methods.

r.status

Status code value, can be assigned.

r.subrequest(uri[, options[, callback]])

Purpose: Creates a sub-request.
options parameter: If a string is passed, it should be the request parameter string. If an object is passed, it can contain the following fields:

args: request parameter string, default is empty.
body: request body, defaults to the parent request’s body.
method: request method, defaults to GET.
detached: boolean type, if true, the response of the created sub-request will be ignored.

callback parameter: response callback function. If no callback function is passed, the subrequest method will return a Promise object.

r.uri

Gets the URI of the current request, read-only.

r.rawVariables

Gets the value of nginx variables, with the value data type as buffer.

r.variables

Gets the value of nginx variables, with the value data type as object. For example, to get the value of the foo variable, use r.variables.foo.

r.warn(string)

Writes a warning-level log to the error log.

2. Testing

1. Print logs

JS code

async function demo(r) {
  // Log
  r.log("This is an info log");
  r.warn("This is a warn log");
  r.error("This is an error log");

  r.log(`r.variables, host variable value: ${r.variables.host}`);
  r.log(`r.uri: ${r.uri}`);
  r.log(`r.method: ${r.method}`);
  r.log(`r.args.name: ${r.args.name}`);
  r.log(`r.headersIn.UserAgent: ${r.headersIn["User-Agent"]}`);
  r.log(`r.remoteAddress: ${r.remoteAddress}`);

  // Create sub-request
  let res = await r.subrequest("/sub");
  r.log(`/sub sub-request returned: ${res.responseText}, ${res.status}`);

  r.return(200, "demo");
}


export default { demo };

Nginx configuration

worker_processes  1;

load_module modules/ngx_http_js_module.so;

events {
    worker_connections  1024;
}


http {
 # Set JS file directory
 js_path "/usr/local/nginx/njs";
 js_import request.js;

 error_log logs/error.log info;


    server {
        listen 89;
        server_name localhost;
        default_type text/plain;
        charset utf-8;

        location /demo {
            js_content request.demo;
        }
        
         location /sub {
            return 200 "sub path";
        }
    }
}

2. Output response content

JS code

async function demo(r) {
  // Set status code
  r.status = 200;
  // Set response header
  r.headersOut["Content-Type"] = "text/plain;charset=utf-8";
  r.headersOut["X-Custom-Head"] = "nginx njs";
  r.sendHeader();
  // Response body content
  r.send("Content returned by send method");
  r.finish();
}

export default { demo };

Nginx configuration

http {
    js_path "/usr/local/nginx/njs";
    js_import request.js;


    server {
        listen 89;
        server_name localhost;

        location /demo {
            js_content request.demo;
        }
    }
}

1. Summary of Methods and Properties of the HTTP Object in the JS Module

2. Testing

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