Examples

Examples

• Hello World
• HTTP Аuthorization
• Creating HS JWT
• Creating secure_link Hash
• Getting Arbitrary Field from JWT as nginx Variable
• HTTP Proxying
• Accessing API from a Subrequest
• Returning Fastest Response from Proxy
• Subrequests Chaining
• Miscellaneous
• Internal Redirect
• Logging the Number of Requests Per Client

The examples work since 0.4.0.

Hello World

nginx.conf:

events {}

http {
    js_import http.js;

    server {
        listen 8000;

        location / {
            js_content http.hello;
        }
    }
}

http.js:

function hello(r) {
    r.return(200, "Hello world!");
}

export default {hello};

Creating HS JWT

nginx.conf:

js_import http.js;

js_set $jwt http.jwt;

http.js:

function generate_hs256_jwt(claims, key, valid) {
    var header = { typ: "JWT",  alg: "HS256" };
    var claims = Object.assign(claims, {exp: Math.floor(Date.now()/1000) + valid});

    var s = [header, claims].map(JSON.stringify)
                            .map(v=>v.toString('base64url'))
                            .join('.');

    var h = require('crypto').createHmac('sha256', key);

    return s + '.' + h.update(s).digest('base64url');
}

function jwt(r) {
    var claims = {
        iss: "nginx",
        sub: "alice",
        foo: 123,
        bar: "qq",
        zyx: false
    };

    return generate_hs256_jwt(claims, 'foo', 600);
}

export default {jwt};

Creating secure_link Hash

nginx.conf:

js_import http.js;

js_set $new_foo http.create_secure_link;
...

location / {
    secure_link $cookie_foo;
    secure_link_md5 "$uri mykey";
    ...
}

location @login {
    add_header Set-Cookie "foo=$new_foo; Max-Age=60";
    return 302 /;
}

http.js:

function create_secure_link(r) {
    return require('crypto').createHash('md5')
                            .update(r.uri).update(" mykey")
                            .digest('base64url');
}

export default {create_secure_link};

Getting Arbitrary Field from JWT as nginx Variable

nginx.conf:

js_import http.js;

js_set $jwt_payload_sub main.jwt_payload_sub;

server {
    ...

    location /jwt {
        return 200 $jwt_payload_sub;
    }
}

http.js:

function jwt(data) {
    var parts = data.split('.').slice(0,2)
        .map(v=>Buffer.from(v, 'base64url').toString())
        .map(JSON.parse);
    return { headers:parts[0], payload: parts[1] };
}

function jwt_payload_sub(r) {
    return jwt(r.headersIn.Authorization.slice(7)).payload.sub;
}

export default {jwt_payload_sub}

Accessing API from a Subrequest

nginx.conf:

js_import http.js;

keyval_zone zone=foo:10m;
...

location /keyval {
    js_content http.set_keyval;
}

location /version {
    js_content http.version;
}

location /api {
    api write=on;
}

http.js:

function set_keyval(r) {
    r.subrequest('/api/5/http/keyvals/foo',
        { method: 'POST',
          body: JSON.stringify({ foo: 789, bar: "ss dd 00" })},

        function(res) {
            if (res.status >= 300) {
                r.return(res.status, res.responseBody);
                return;
            }
            r.return(500);
        });
}

function version(r) {
    r.subrequest('/api/5/nginx', { method: 'GET' }, function(res) {
        if (res.status != 200) {
            r.return(res.status);
            return;
        }

        var json = JSON.parse(res.responseBody);
        r.return(200, json.version);
    });
}

export default {set_keyval, version};

Returning Fastest Response from Proxy

nginx.conf:

js_import http.js;

location /start {
    js_content http.content;
}

location /foo {
    proxy_pass http://backend1;
}

location /bar {
    proxy_pass http://backend2;
}

http.js:

function content(r) {
    var n = 0;

    function done(res) {
        if (n++ == 0) {
            r.return(res.status, res.responseBody);
        }
    }

    r.subrequest('/foo', r.variables.args, done);
    r.subrequest('/bar', r.variables.args, done);
}

export default {content};

Subrequests Chaining

nginx.conf:

js_import http.js;

location /start {
    js_content http.content;
}

location /auth {
    proxy_pass http://auth_backend;
}

location /backend {
    proxy_pass http://backend;
}

http.js:

function content(r) {
   r.subrequest('/auth')
   .then(reply => JSON.parse(reply.responseBody))
   .then(response => {
       if (!response['token']) {
           throw new Error("token is not available");
       }
       return reply['token'];
   })
  .then(token => {
      r.subrequest('/backend', `token=${token}`)
      .then(reply => r.return(reply.status, reply.responseBody));
  })
  .catch(_ => r.return(500));
}

export default {content};

Internal Redirect

nginx.conf:

js_import http.js;

location /redirect {
    js_content http.redirect;
}

location @named {
    return 200 named;
}

http.js:

function redirect(r) {
    r.internalRedirect('@named');
}

export default {redirect};

Logging the Number of Requests Per Client

nginx.conf:

js_import http.js;

js_set $num_requests http.num_requests;

keyval_zone zone=foo:10m;

keyval $remote_addr $foo zone=foo;

log_format bar '$remote_addr [$time_local] $num_requests';
access_log logs/access.log bar;

server {
    listen 8000;

    location / {
        root html;
    }
}

http.js:

function num_requests(r)
{
    var n = r.variables.foo;
    n = n ? Number(n) + 1 : 1;
    r.variables.foo = n;
    return n;
}

export default {num_requests};

The keyval and keyval_zone directives are available as part of our commercial subscription.

© 2002-2021 Igor Sysoev
© 2011-2021 Nginx, Inc.
Licensed under the BSD License.
https://nginx.org/en/docs/njs/examples.html