EdgeScript built-in variables - CDN - Alibaba Cloud Documentation Center

EdgeScript built-in variables map directly to NGINX variables and give your scripts read-only access to request properties: the URI, query parameters, headers, cookies, client IP, and protocol details.

Built-in variables are read-only. Do not assign values to them.

The dollar sign ($) prefix identifies a variable as a built-in variable. You can omit the $ prefix if your business logic requires it.

Variable limit

A single script supports at most 200 variables. If your rule requires more, split the logic into multiple user-defined functions, each containing no more than 200 variables. See Splitting function for an example.

Handling hyphens in variable names

Three built-in variables — $arg_{name}, $http_{name}, and $cookie_{name} — use a {name} placeholder for a query string key, request header field, or cookie field. Each handles hyphens differently:

Variable	Hyphen handling
`$arg_{name}`	If `{name}` contains a hyphen, use `req_uri_arg('{name}')` instead. Example: `req_uri_arg('example-demo')` for `?example-demo=123`
`$http_{name}`	Replace hyphens with underscores. Example: `$http_x_user_id` for the `X-USER-ID` header
`$cookie_{name}`	If `{name}` contains a hyphen, use `req_cookie('{name}')` instead. Example: `req_cookie('example-demo')` for `cookie: example-demo=123`

Built-in variables

Variable	Returns	NGINX variable
`$arg_{name}`	Value of the `{name}` key in the query string	`$arg_`
`$http_{name}`	Value of the `{name}` field in the request header	`$http_`
`$cookie_{name}`	Value of the `{name}` field in the request cookie header	`$cookie_`
`$scheme`	Protocol type	`$scheme`
`$server_protocol`	Protocol version	`$server_protocol`
`$host`	Original host	`$host`
`$uri`	Original URI	None
`$args`	All query string parameters, excluding the leading `?`	`$args`
`$request_method`	Request method	`$request_method`
`$request_uri`	Full request URI, equivalent to `uri + '?' + args`	`$request_uri`
`$remote_addr`	Client IP address used to connect to the points of presence (POPs)	`$remote_addr`

Example: `$arg_{name}` and `$args`

For the request http://example.aliyundoc.com/1k.file?k1=v1&k2=v2:

$arg_k1 returns v1
$args returns k1=v1&k2=v2 (the full query string, without ?)

Splitting function

When a rule contains more than 200 variables, split the original function into multiple user-defined functions. Each user-defined function must contain no more than 200 variables.

#If variables exceed the limit, split them like this:
def judeg_arg() {
  #Parameter judgment related logic
  x
  x
}

def judeg_time() {
  #Time judgment related logic
  x
  x
}

def judeg_token() {
  #Encryption judgment related logic
  x
  x
}

judeg_arg()
judeg_time()
judeg_token()

Variable limit

Handling hyphens in variable names

Built-in variables

Example: $arg_{name} and $args

Splitting function

Example: `$arg_{name}` and `$args`