<?xml version="1.0"?>

<!--
  Copyright (C) Nginx, Inc.
  -->

<!DOCTYPE article SYSTEM "../../../../dtd/article.dtd">

<article name="njs API"
        link="/en/docs/njs/njs_api.html"
        lang="en"
        rev="2">

<section id="summary">

<para>
<link doc="../njs_about.xml">njs</link> provides objects, methods and properties
for extending nginx functionality.
</para>

</section>


<section id="core" name="Core">


<section id="string" name="String">

<para>
There are two types of strings:
a <literal>Unicode string</literal> (default) and
a <literal>byte string</literal>.
</para>

<para>
A <literal>Unicode string</literal> corresponds to an ECMAScript string
which contains Unicode characters.
</para>

<para>
<literal>Byte strings</literal> contain a sequence of bytes.
They are used to serialize Unicode strings
to external data and deserialize from external sources.
For example, the <link id="string_toutf8">toUTF8()</link> method serializes
a Unicode string to a byte string using UTF8 encoding:
<example>
>> '£'.toUTF8().toString('hex')
c2a3  /* C2 A3 is the UTF8 representation of 00A3 ('£') code point */
</example>
The <link id="string_tobytes">toBytes()</link> method serializes
a Unicode string with code points up to 255 into a byte string,
otherwise, <literal>null</literal> is returned:
<example>
>> '£'.toBytes().toString('hex')
a3  /* a3 is a byte equal to 00A3 ('£') code point  */
</example>
Only byte strings can be converted to different encodings.
For example, a string cannot be encoded to <literal>hex</literal> directly:
<example>
>> 'αβγδ'.toString('base64')
TypeError: argument must be a byte string
    at String.prototype.toString (native)
    at main (native)
</example>
To convert a Unicode string to hex,
first, it should be converted to a byte string and then to hex:
<example>
>> 'αβγδ'.toUTF8().toString('base64')
zrHOss6zzrQ=
</example>

<list type="tag">

<tag-name><literal>String.fromCodePoint(<value>codePoint1</value>[, ...[,
<value>codePoint2</value>]])</literal></tag-name>
<tag-desc>
Returns a string from one or more Unicode code points.
<example>
>> String.fromCodePoint(97, 98, 99, 100)
abcd
</example>
</tag-desc>

<tag-name><literal>String.prototype.concat(<value>string1</value>[, ...,
<value>stringN</value>])</literal></tag-name>
<tag-desc>
Returns a string that contains the concatenation of specified
<literal>strings</literal>.
<example>
>> "a".concat("b", "c")
abc
</example>
</tag-desc>

<tag-name><literal>String.prototype.endsWith(<value>searchString</value>[,
<value>length</value>])</literal></tag-name>
<tag-desc>
Returns <literal>true</literal> if a string ends with the characters
of a specified string, otherwise <literal>false</literal>.
The optional <literal>length</literal> parameter is the the length of string.
If omitted, the default value is the length of the string.
<example>
>> 'abc'.endsWith('abc')
true
>> 'abca'.endsWith('abc')
false
</example>
</tag-desc>

<tag-name><literal>String.prototype.fromBytes(<value>start</value>[,
<value>end</value>])</literal></tag-name>
<tag-desc>
(njs specific) Returns a new Unicode string from a byte string
where each byte is replaced with a corresponding Unicode code point.
</tag-desc>

<tag-name><literal>String.prototype.fromUTF8(<value>start</value>[,
<value>end</value>])</literal></tag-name>
<tag-desc>
(njs specific) Converts a byte string containing a valid UTF8 string
into a Unicode string,
otherwise <literal>null</literal> is returned.
</tag-desc>

<tag-name><literal>String.prototype.includes(<value>searchString</value>[,
<value>position</value>]))</literal></tag-name>
<tag-desc>
Returns <literal>true</literal> if a string is found within another string,
otherwise <literal>false</literal>.
The optional <literal>position</literal> parameter is the position
within the string at which to begin search for <literal>searchString</literal>. 
Default value is 0.
<example>
>> 'abc'.includes('bc')
true
</example>
</tag-desc>

<tag-name><literal>String.prototype.indexOf(<value>searchString</value>[,
<value>fromIndex</value>])</literal></tag-name>
<tag-desc>
Returns the position of the first occurrence
of the <literal>searchString</literal>
The search is started at <literal>fromIndex</literal>.
Returns <value>-1</value> if the value is not found.
The <literal>fromIndex</literal> is an integer,
default value is 0.
If <literal>fromIndex</literal> is lower than 0
or greater than
<link id="string_length">String.prototype.length</link><value></value>,
the search starts at index <value>0</value> and
<value>String.prototype.length</value>.
<example>
>> 'abcdef'.indexOf('de', 2)
3
</example>
</tag-desc>

<tag-name><literal>String.prototype.lastIndexOf(<value>searchString</value>[,
<value>fromIndex</value>])</literal></tag-name>
<tag-desc>
Returns the position of the last occurrence
of the <literal>searchString</literal>,
searching backwards from <literal>fromIndex</literal>.
Returns <value>-1</value> if the value is not found.
If <literal>searchString</literal>  is empty,
then <literal>fromIndex</literal> is returned.
<example>
>> "nginx".lastIndexOf("gi")
1
</example>
</tag-desc>

<tag-name id="string_length"><literal>String.prototype.length</literal></tag-name>
<tag-desc>
Returns the length of the string.
<example>
>> 'αβγδ'.length
4
</example>
</tag-desc>

<tag-name><literal>String.prototype.match([<value>regexp</value>])</literal></tag-name>
<tag-desc>
Matches a string against a <literal>regexp</literal>.
<example>
>> 'nginx'.match( /ng/i )
ng
</example>
</tag-desc>

<tag-name><literal>String.prototype.repeat(<value>number</value>)</literal></tag-name>
<tag-desc>
Returns a string 
with the specified <literal>number</literal> of copies of the string.
<example>
>> 'abc'.repeat(3)
abcabcabc
</example>
</tag-desc>

<tag-name><literal>String.prototype.replace([<value>regexp</value>|<value>string</value>[,
<value>string</value>|<value>function</value>]])</literal></tag-name>
<tag-desc>
Returns a new string with matches of a pattern
(<literal>string</literal> or a <literal>regexp</literal>)
replaced by a <literal>string</literal> or a <literal>function</literal>.
<example>
>> 'abcdefgh'.replace('d', 1)
abc1efgh
</example>
</tag-desc>

<tag-name><literal>String.prototype.search([<value>regexp</value>])</literal></tag-name>
<tag-desc>
Searches for a string using a <literal>regexp</literal>
<example>
>> 'abcdefgh'.search('def')
3
</example>
</tag-desc>

<tag-name><literal>String.prototype.slice(<value>start</value>[,
<value>end</value>])</literal></tag-name>
<tag-desc>
Returns a new string containing a part of an
original string between <literal>start</literal>
and <literal>end</literal> or
from <literal>start</literal> to the end of the string.
<example>
>> 'abcdefghijklmno'.slice(NaN, 5)
abcde
</example>
</tag-desc>

<tag-name><literal>String.prototype.startsWith(<value>searchString</value>[,
<value>position</value>])</literal></tag-name>
<tag-desc>
Returns <literal>true</literal> if a string begins with the characters
of a specified string, otherwise <literal>false</literal>.
The optional <literal>position</literal> parameter is the position
in this string at which to begin search for <literal>searchString</literal>.
Default value is 0.
<example>
>> 'abc'.startsWith('abc')
true
> 'aabc'.startsWith('abc')
false
</example>
</tag-desc>

<tag-name><literal>String.prototype.substr(<value>start</value>[,
<value>length</value>])</literal></tag-name>
<tag-desc>
Returns the part of the string of the specified <literal>length</literal>
from <literal>start</literal>
or from <literal>start</literal> to the end of the string.
<example>
>>  'abcdefghijklmno'.substr(3, 5)
defgh
</example>
</tag-desc>

<tag-name><literal>String.prototype.substring(<value>start</value>[,
<value>end</value>])</literal></tag-name>
<tag-desc>
Returns the part of the string between
<literal>start</literal> and <literal>end</literal> or
from <literal>start</literal> to the end of the string.
<example>
>> 'abcdefghijklmno'.substring(3, 5)
de
</example>
</tag-desc>

<tag-name id="string_tobytes"><literal>String.prototype.toBytes(start[,
end])</literal></tag-name>
<tag-desc>
(njs specific) Serializes a Unicode string to a byte string.
Returns <literal>null</literal> if a character larger than 255 is
found in the string.
</tag-desc>

<tag-name><literal>String.prototype.toLowerCase()</literal></tag-name>
<tag-desc>
Converts a string to lower case.
The method supports only simple Unicode folding.
<example>
>> 'ΑΒΓΔ'.toLowerCase()
αβγδ
</example>
</tag-desc>

<tag-name><literal>String.prototype.toString([<value>encoding</value>])</literal></tag-name>
<tag-desc>
<para>
If no <literal>encoding</literal> is specified,
returns a specified Unicode string or byte string as in ECMAScript.
</para>

<para>
(njs specific) If <literal>encoding</literal> is specified,
encodes a <link id="string_tobytes">byte string</link> to
<literal>hex</literal>,
<literal>base64</literal>, or
<literal>base64url</literal>.
</para>
<example>
>>  'αβγδ'.toUTF8().toString('base64url')
zrHOss6zzrQ
</example>
</tag-desc>

<tag-name><literal>String.prototype.toUpperCase()</literal></tag-name>
<tag-desc>
Converts a string to upper case.
The method supports only simple Unicode folding.
<example>
>> 'αβγδ'.toUpperCase()
ΑΒΓΔ
</example>
</tag-desc>

<tag-name id="string_toutf8"><literal>String.prototype.toUTF8(<value>start</value>[,
<value>end</value>])</literal></tag-name>
<tag-desc>
(njs specific) Serializes a Unicode string
to a byte string using UTF8 encoding.
<example>
>> 'αβγδ'.toUTF8().length
8
>> 'αβγδ'.length
4
</example>
</tag-desc>

<tag-name><literal>String.prototype.trim()</literal></tag-name>
<tag-desc>
Removes whitespaces from both ends of a string.
<example>
>> '   abc  '.trim()
abc
</example>
</tag-desc>

<tag-name><literal>String.prototype.split(([<value>string</value>|<value>regexp</value>[,
<value>limit</value>]]))</literal></tag-name>
<tag-desc>
Returns match of a string against a <literal>regexp</literal>.
The optional <literal>limit</literal> parameter is an integer that specifies
a limit on the number of splits to be found.
<example>
>> 'abc'.split('')
a,b,c
</example>
</tag-desc>

<tag-name id="encodeuri"><literal>encodeURI(<value>URI</value>)</literal></tag-name>
<tag-desc>
encodes a URI by replacing each instance of certain characters by
one, two, three, or four escape sequences
representing the UTF-8 encoding of the character
<example>
>> encodeURI('012αβγδ')
012%CE%B1%CE%B2%CE%B3%CE%B4
</example>
</tag-desc>

<tag-name><literal>encodeURIComponent(<value>encodedURIString</value>)</literal></tag-name>
<tag-desc>
Encodes a URI by replacing each instance of certain characters
by one, two, three, or four escape sequences
representing the UTF-8 encoding of the character.
<example>
>> encodeURIComponent('[@?=')
%5B%40%3F%3D
</example>
</tag-desc>

<tag-name><literal>decodeURI(<value>encodedURI</value>)</literal></tag-name>
<tag-desc>
Decodes a previously <link id="encodeuri">encoded</link> URI.
<example>
>> decodeURI('012%CE%B1%CE%B2%CE%B3%CE%B4')
012αβγδ
</example>
</tag-desc>

<tag-name><literal>decodeURIComponent(<value>decodedURIString</value>)</literal></tag-name>
<tag-desc>
Decodes an encoded component of a previously encoded URI.
<example>
>> decodeURIComponent('%5B%40%3F%3D')
[@?=
</example>
</tag-desc>

</list>
</para>

</section>


<section id="core_json" name="JSON">

<para>
The <literal>JSON</literal> object (ES 5.1) provides functions
to convert njs values to and from JSON format.
<list type="tag">

<tag-name><literal>JSON.parse(<value>string</value>[,
<value>reviver</value>])</literal></tag-name>
<tag-desc>
Converts a <literal>string</literal> that represents JSON data
into an njs object (<literal>{...}</literal>) or
array (<literal>[...]</literal>).
The optional <literal>reviver</literal> parameter is a function (key, value)
that will be called for each (key,value) pair and can transform the value.
</tag-desc>

<tag-name><literal>JSON.stringify(<value>value</value>[,
<value>replacer</value>] [, <value>space</value>])</literal></tag-name>
<tag-desc>
Converts an njs object back to JSON.
The obligatory <literal>value</literal> parameter is generally a JSON
<literal>object</literal> or <literal>array</literal> that will be converted.
If the value has a <literal>toJSON()</literal> method,
it defines how the object will be serialized.
The optional <literal>replacer</literal> parameter is
a <literal>function</literal> or <literal>array</literal>
that transforms results.
The optional <literal>space</literal> parameter is
a <literal>string</literal> or <literal>number</literal>.
If it is a <literal>number</literal>,
it indicates the number of white spaces placed before a result
(no more than 10).
If it is a <literal>string</literal>,
it is used as a white space (or first 10 characters of it).
If omitted or is <literal>null</literal>, no white space is used.
</tag-desc>
</list>
</para>

<para>
<example>
>> var json = JSON.parse('{"a":1, "b":true}')
>> json.a
1

>> JSON.stringify(json)
{"a":1,"b":true}

>> JSON.stringify(json, undefined, 1)
{
"a": 1,
"b": true
}

>> JSON.stringify({ x: [10, undefined, function(){}] })
{"x":[10,null,null]}

>> JSON.stringify({"a":1, "toJSON": function() {return "xxx"}})
"xxx"

# Example with function replacer

>> function replacer(key, value) {return (typeof value === 'string') ? undefined : value}
>>JSON.stringify({a:1, b:"b", c:true}, replacer)
{"a":1,"c":true}
</example>
</para>

</section>


<section id="crypto" name="Crypto">

<para>
The Crypto module provides cryptographic functionality support.
The Crypto module object is returned by <literal>require('crypto')</literal>.
</para>

<para>
<list type="tag">

<tag-name><literal>crypto.createHash(<value>algorithm</value>)</literal></tag-name>
<tag-desc>
Creates and returns a <link id="crypto_hash">Hash</link> object
that can be used to generate hash digests
using the given <value>algorithm</value>.
The algorighm can be
<literal>md5</literal>,
<literal>sha1</literal>, and
<literal>sha256</literal>.
</tag-desc>

<tag-name><literal>crypto.createHmac(<value>algorithm</value>,
<value>secret key</value>)</literal></tag-name>
<tag-desc>
Creates and returns an <link id="crypto_hmac">HMAC</link> object
that uses the given <value>algorithm</value> and <value>secret key</value>.
The algorighm can be
<literal>md5</literal>,
<literal>sha1</literal>, and
<literal>sha256</literal>.
</tag-desc>

</list>
</para>


<section id="crypto_hash" name="Hash">

<para>
<list type="tag">

<tag-name><literal>hash.update(<value>data</value>)</literal></tag-name>
<tag-desc>
Updates the hash content with the given <value>data</value>.
</tag-desc>

<tag-name><literal>hash.digest([<value>encoding</value>])</literal></tag-name>
<tag-desc>
Calculates the digest of all of the data passed using
<literal>hash.update()</literal>.
The encoding can be
<literal>hex</literal>,
<literal>base64</literal>, and
<literal>base64url</literal>.
If encoding is not provided, a byte string is returned.
</tag-desc>

</list>
</para>

<para>
<example>
>> var cr = require('crypto')
undefined

>> cr.createHash('sha1').update('A').update('B').digest('base64url')
BtlFlCqiamG-GMPiK_GbvKjdK10
</example>
</para>

</section>


<section id="crypto_hmac" name="HMAC">

<para>
<list type="tag">

<tag-name><literal>hmac.update(<value>data</value>)</literal></tag-name>
<tag-desc>
Updates the HMAC content with the given <value>data</value>.
</tag-desc>

<tag-name><literal>hmac.digest([<value>encoding</value>])</literal></tag-name>
<tag-desc>
Calculates the HMAC digest of all of the data passed using
<literal>hmac.update()</literal>.
The encoding can be
<literal>hex</literal>,
<literal>base64</literal>, and
<literal>base64url</literal>.
If encoding is not provided, a byte string is returned.
</tag-desc>
</list>
</para>

<para>
<example>
>> var cr = require('crypto')
undefined

>> cr.createHmac('sha1', 'secret.key').update('AB').digest('base64url')
Oglm93xn23_MkiaEq_e9u8zk374
</example>
</para>

</section>

</section>

</section>


<section id="http" name="HTTP">

<para>
The <literal>HTTP</literal> object is available only in the
<link doc="../http/ngx_http_js_module.xml">ngx_http_js_module</link> module.
All string properties of the <literal>HTTP</literal> object are
<link id="string">byte strings</link>.
</para>


<section id="http_request" name="Request">

<para>
<list type="tag">

<tag-name><literal>r.args{}</literal></tag-name>
<tag-desc>
request arguments object, read-only
</tag-desc>

<tag-name><literal>r.error(<value>string</value>)</literal></tag-name>
<tag-desc>
writes a <literal>string</literal> to the error log
on the <literal>error</literal> level of logging
</tag-desc>

<tag-name><literal>r.finish()</literal></tag-name>
<tag-desc>
finishes sending a response to the client
</tag-desc>

<tag-name><literal>r.headersIn{}</literal></tag-name>
<tag-desc>
incoming headers object, read-only.
<para>
For example, the <literal>Header-Name</literal> header
can be accessed with the syntax <literal>headers['Header-Name']</literal>
or <literal>headers.Header_name</literal>
</para>
</tag-desc>

<tag-name><literal>r.headersOut{}</literal></tag-name>
<tag-desc>
outgoing headers object, writable.
<para>
For example, the <literal>Header-Name</literal> header
can be accessed with the syntax <literal>headers['Header-Name']</literal>
or <literal>headers.Header_name</literal>
</para>
</tag-desc>

<tag-name><literal>r.httpVersion</literal></tag-name>
<tag-desc>
HTTP version, read-only
</tag-desc>

<tag-name><literal>r.log(<value>string</value>)</literal></tag-name>
<tag-desc>
writes a <literal>string</literal> to the error log
on the <literal>info</literal> level of logging
</tag-desc>

<tag-name id="r_internal_redirect"><literal>r.internalRedirect(<value>uri</value>)</literal></tag-name>
<tag-desc>
performs an internal redirect to the specified <literal>uri</literal>.
If the uri starts with the “<literal>@</literal>” prefix,
it is considered a named location.
</tag-desc>

<tag-name><literal>r.method</literal></tag-name>
<tag-desc>
HTTP method, read-only
</tag-desc>

<tag-name><literal>r.parent</literal></tag-name>
<tag-desc>
references the parent request object
</tag-desc>

<tag-name><literal>r.remoteAddress</literal></tag-name>
<tag-desc>
client address, read-only
</tag-desc>

<tag-name><literal>r.requestBody</literal></tag-name>
<tag-desc>
holds the request body, read-only
</tag-desc>

<tag-name><literal>r.responseBody</literal></tag-name>
<tag-desc>
holds the <link id="subrequest">subrequest</link> response body, read-only.
The size of <literal>r.responseBody</literal> is limited by the
<link doc="../http/ngx_http_core_module.xml" id="subrequest_output_buffer_size"/>
directive.
</tag-desc>

<tag-name><literal>r.return(status[, string])</literal></tag-name>
<tag-desc>
sends the entire response
with the specified <literal>status</literal> to the client
<para>
It is possible to specify either a redirect URL
(for codes 301, 302, 303, 307, and 308)
or the response body text (for other codes) as the second argument
</para>
</tag-desc>

<tag-name><literal>r.send(<value>string</value>)</literal></tag-name>
<tag-desc>
sends a part of the response body to the client
</tag-desc>

<tag-name><literal>r.sendHeader()</literal></tag-name>
<tag-desc>
sends the HTTP headers to the client
</tag-desc>

<tag-name><literal>r.status</literal></tag-name>
<tag-desc>
status, writable
</tag-desc>

<tag-name><literal>r.variables{}</literal></tag-name>
<tag-desc>
nginx variables object, read-only
</tag-desc>

<tag-name><literal>r.warn(<value>string</value>)</literal></tag-name>
<tag-desc>
writes a <literal>string</literal> to the error log
on the <literal>warning</literal> level of logging
</tag-desc>

<tag-name><literal>r.uri</literal></tag-name>
<tag-desc>
current URI, read-only
</tag-desc>

<tag-name id="subrequest"><literal>r.subrequest(<value>uri</value>[,
<value>options</value>[, <value>callback</value>]])</literal></tag-name>
<tag-desc>
creates a subrequest with the given <literal>uri</literal> and
<literal>options</literal>, and installs
an optional completion <literal>callback</literal>.

<para>
If <literal>options</literal> is a string, then it
holds the subrequest arguments string.
Otherwise, <literal>options</literal> is expected to be
an object with the following keys:

<list type="tag">
<tag-name><literal>args</literal></tag-name>
<tag-desc>
arguments string
</tag-desc>

<tag-name><literal>body</literal></tag-name>
<tag-desc>
request body
</tag-desc>

<tag-name><literal>method</literal></tag-name>
<tag-desc>
HTTP method
</tag-desc>

</list>
</para>

<para>
The completion <literal>callback</literal> receives
a subrequest response object with methods and properties
identical to the parent request object.
</para>
</tag-desc>

</list>
</para>

</section>

</section>


<section id="stream" name="Stream">

<para>
The <literal>stream</literal> object is available only in the
<link doc="../stream/ngx_stream_js_module.xml">ngx_stream_js_module</link>
module.
All string properties of the <literal>stream</literal> object are
<link id="string">byte strings</link>.
</para>


<section id="stream_session" name="Session">

<para>
<list type="tag">

<tag-name><literal>s.remoteAddress</literal></tag-name>
<tag-desc>
client address, read-only
</tag-desc>

<tag-name><literal>s.eof</literal></tag-name>
<tag-desc>
a boolean read-only property, true if the current buffer is the last buffer
</tag-desc>

<tag-name><literal>s.fromUpstream</literal></tag-name>
<tag-desc>
a boolean read-only property,
true if the current buffer is from the upstream server to the client
</tag-desc>

<tag-name><literal>s.buffer</literal></tag-name>
<tag-desc>
the current buffer, writable
</tag-desc>

<tag-name><literal>s.variables{}</literal></tag-name>
<tag-desc>
nginx variables object, read-only
</tag-desc>

<tag-name><literal>s.OK</literal></tag-name>
<tag-desc>
the <literal>OK</literal> return code
</tag-desc>

<tag-name><literal>s.DECLINED</literal></tag-name>
<tag-desc>
the <literal>DECLINED</literal> return code
</tag-desc>

<tag-name><literal>s.AGAIN</literal></tag-name>
<tag-desc>
the <literal>AGAIN</literal> return code
</tag-desc>

<tag-name><literal>s.ERROR</literal></tag-name>
<tag-desc>
the <literal>ERROR</literal> return code
</tag-desc>

<tag-name><literal>s.ABORT</literal></tag-name>
<tag-desc>
the <literal>ABORT</literal> return code
</tag-desc>

<tag-name><literal>s.log(<value>string</value>)</literal></tag-name>
<tag-desc>
writes a sent <value>string</value> to the error log
on the <literal>info</literal> level of logging
</tag-desc>

<tag-name><literal>s.warn(<value>string</value>)</literal></tag-name>
<tag-desc>
writes a sent <literal>string</literal> to the error log
on the <literal>warning</literal> level of logging
</tag-desc>

<tag-name><literal>s.error(<value>string</value>)</literal></tag-name>
<tag-desc>
writes a sent <literal>string</literal> to the error log
on the <literal>error</literal> level of logging
</tag-desc>

</list>
</para>

</section>

</section>


<section id="example" name="Examples">


<section id="example_urldecode" name="URL Decoding">

<para>
<example>
js_include urldecode.js;

js_set $decoded_foo decoded_foo;
</example>
</para>

<para>
The <path>urldecode.js</path> file:
<example>
function decoded_foo(r) {
    return decodeURIComponent(r.args.foo);
}
</example>
</para>

</section>


<section id="example_urlencode" name="URL Encoding">

<para>
<example>
js_include urlencode.js;

js_set $encoded_foo encoded_foo;
...

location / {
    proxy_pass http://example.com?foo=$encoded_foo;
}
</example>
</para>

<para>
The <path>urlencode.js</path> file:
<example>
function encoded_foo(r) {
    return encodeURIComponent('foo &amp; bar?');
}
</example>
</para>

</section>


<section id="example_internal_redirect" name="Internal Redirect">

<para>
<example>
js_include redirect.js;

location /redirect {
    js_content redirect;
}

@named {
    return 200 named;
}
</example>
</para>

<para>
The <path>redirect.js</path> file:
<example>
function redirect(r) {
    r.internalRedirect('@named');
}
</example>
</para>

</section>


<section id="example_fast_response" name="Returning Fastest Response from Proxy">

<para>
<example>
js_include fastresponse.js;

location /start {
    js_content content;
}

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

location /bar {
    proxy_pass http://backend2;
}
</example>
</para>

<para>
The <path>fastresponse.js</path> file:
<example>
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);
}
</example>
</para>

</section>


<section id="example_jwt" name="Creating HS JWT">

<para>
<example>
js_include hs_jwt.js;

js_set $jwt jwt;
</example>
</para>

<para>
The <path>hs_jwt.js</path> file:
<example>
function create_hs256_jwt(claims, key, valid) {
    var header = { "typ" : "JWT", "alg" : "HS256", "exp" : Date.now() + valid };

    var s = JSON.stringify(header).toBytes().toString('base64url') + '.'
            + JSON.stringify(claims).toBytes().toString('base64url');

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

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

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

    return create_hs256_jwt(claims, 'foo', 600);
}
</example>
</para>

</section>


<section id="example_subrequest" name="Accessing API from a Subrequest">

<para>
<example>
js_include subrequest.js;

keyval_zone zone=foo:10m;
...

location /keyval {
    js_content set_keyval;
}

location /version {
    js_content version;
}

location /api {
    api write=on;
}
</example>
</para>

<para>
The <path>subrequest.js</path> file:
<example>
function set_keyval(r) {
    r.subrequest('/api/3/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/3/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);
    });
}
</example>
</para>

</section>


<section id="example_secure_link" name="Creating secure_link Hash">

<para>
<example>
js_include hash.js;

js_set $new_foo 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 /;
}
</example>
</para>

<para>
The <path>hash.js</path> file:
<example>
function create_secure_link(r) {
    return require('crypto').createHash('md5')
                            .update(r.uri).update(" mykey")
                            .digest('base64url');
}
</example>
</para>

</section>

</section>

</article>