Request processing functions

Adds an request header to back-to-origin requests.

• name: the name of the request header that you want to add. Data type: string.
• value: the value of the request header that you want to add. Data type: string.
• append: specifies whether to append a request header with the specified value if a request header with the same name already exists. Valid values: true and false. Default value: false. If you set this parameter to false, the specified value will overwrite the value of the existing request header.

Returns true by default and returns false if you have specified an invalid request header.

add_req_header('USER-DEFINED-REQ-1', '1')
add_req_header('USER-DEFINED-REQ-1', 'x', true)
add_req_header('USER-DEFINED-REQ-2', '2')
del_req_header('USER-DEFINED-REQ-2')

The following request headers are added:
USER-DEFINED-REQ-1: 1
USER-DEFINED-REQ-1: x

The USER-DEFINED-REQ-2 header is added first and then deleted. Therefore, the USER-DEFINED-REQ-2 request header is not included in the back-to-origin request.

Deletes a request header from back-to-origin requests.

name: the name of the request header that you want to delete. Data type: string.

Returns true by default and returns false if you have specified an invalid request header.

add_req_header('USER-DEFINED-REQ-1', '1')
add_req_header('USER-DEFINED-REQ-1', 'x', true)
add_req_header('USER-DEFINED-REQ-2', '2')
del_req_header('USER-DEFINED-REQ-2')

The following request headers are added:
USER-DEFINED-REQ-1: 1
USER-DEFINED-REQ-1: x

The USER-DEFINED-REQ-2 header is added first and then deleted. Therefore, the USER-DEFINED-REQ-2 request header is not included in the back-to-origin request.

Adds a response header.

• name: the name of the response header that you want to add. Data type: string.
• value: the value of the response header that you want to add. Data type: string.
  You can specify one of the following expressions for the value parameter to enable the value to be dynamically replaced in the response phase.

  • ${x}: replaced with the value of ngx.var.x.
  • @{y}: replaced with the value of response header y.
• append: specifies whether to append a response header with the specified value if a response header with the same name already exists. Valid values: true and false. Default value: false. If you set this parameter to false, the specified value will overwrite the value of the existing response header.

Returns true by default and returns false if you have specified an invalid response header.

add_rsp_header('USER-DEFINED-RSP-1', '1')
add_rsp_header('USER-DEFINED-RSP-1', 'x', true)
add_rsp_header('USER-DEFINED-RSP-2', '2')
del_rsp_header('USER-DEFINED-RSP-2')

The following response headers are added:
USER-DEFINED-RSP-1: 1
USER-DEFINED-RSP-1: x

The USER-DEFINED-RSP-2 header is added first and then deleted. Therefore, the USER-DEFINED-RSP-2 header is not included in the response.

Deletes a response header.

name: the name of the response header that you want to delete. Data type: string.

Returns true by default and returns false if you have specified an invalid response header.

add_rsp_header('USER-DEFINED-RSP-1', '1')
add_rsp_header('USER-DEFINED-RSP-1', 'x', true)
add_rsp_header('USER-DEFINED-RSP-2', '2')
del_rsp_header('USER-DEFINED-RSP-2')

The following response headers are added:
USER-DEFINED-RSP-1: 1
USER-DEFINED-RSP-1: x

The USER-DEFINED-RSP-2 header is added first and then deleted. Therefore, the USER-DEFINED-RSP-2 header is not included in the response.

Converts the k/v pairs in the dictionary specified by d to a URI-encoded string in the format of k1=v1&k2=v2.

d: the dictionary that you want to convert.

Returns a URI-encoded string.

my_args = []
set(my_args, 'signature', 'da9dc4b7-87ae-4330-aaaf-e5454e2c2af1')
set(my_args, 'algo', 'private sign1')
my_args_str = encode_args(my_args)
add_rsp_header('X-DSL-ENCODE-ARGS', my_args_str)

to_args = decode_args(my_args_str)
if get(to_args, 'algo') {
    add_rsp_header('X-DSL-DECODE-ARGS-ALGO', get(to_args, 'algo'))
}
if get(to_args, 'signature') {
    add_rsp_header('X-DSL-DECODE-ARGS-SIGN', get(to_args, 'signature'))
}

Output: The following response headers are added.
X-DSL-ENCODE-ARGS: signature=da9dc4b7-87ae-4330-aaaf-e5454e2c2af1&algo=private%20sign1
X-DSL-DECODE-ARGS-ALGO: private sign1
X-DSL-DECODE-ARGS-SIGN: da9dc4b7-87ae-4330-aaaf-e5454e2c2af1

Converts a URI-encoded string in the format of k1=v1&k2=v2 to a string of the dictionary type.

s: the string that you want to convert.

Returns a dictionary object converted from the specified string.

my_args = []
set(my_args, 'signature', 'da9dc4b7-87ae-4330-aaaf-e5454e2c2af1')
set(my_args, 'algo', 'private sign1')
my_args_str = encode_args(my_args)
add_rsp_header('X-DSL-ENCODE-ARGS', my_args_str)

to_args = decode_args(my_args_str)
if get(to_args, 'algo') {
    add_rsp_header('X-DSL-DECODE-ARGS-ALGO', get(to_args, 'algo'))
}
if get(to_args, 'signature') {
    add_rsp_header('X-DSL-DECODE-ARGS-SIGN', get(to_args, 'signature'))
}

Output: The following response headers are added.
X-DSL-ENCODE-ARGS: signature=da9dc4b7-87ae-4330-aaaf-e5454e2c2af1&algo=private%20sign1
X-DSL-DECODE-ARGS-ALGO: private sign1
X-DSL-DECODE-ARGS-SIGN: da9dc4b7-87ae-4330-aaaf-e5454e2c2af1

Performs a rewrite or redirect operation.

• url: the URI in the rewrite rule. Data type: string.
  • If you set the flag parameter to redirect or break, only the URI is rewritten. This parameter specifies the URI after the rewrite operation.
  • If you set the flag parameter to enhance_redirect or enhance_break, the URI and parameters are rewritten. This parameter specifies the URI and parameters after the rewrite operation.
• flag: the rewrite mode. Data type: string.
  • redirect: only rewrites the URI. Parameters are not rewritten. By default, a 302 redirect is performed. If you specify this mode, the code parameter is configurable. Valid values for the code parameter are 301, 302 (default), 303, 307, and 308.
  • break: only rewrites the URI to a URL. Parameters are not rewritten.
  • enhance_redirect: similar to redirect. However, both the URI and parameters are rewritten.
  • enhance_break: similar to break. However, both the URI and parameters are rewritten.
• code: the HTTP status code. Data type: numeric.

  This parameter is available for customization only when you set the flag parameter to redirect or enhance_redirect.

• Returns true by default for a rewrite operation.
• Does not return a value by default for a rewrite operation.

if and($arg_mode, eq($arg_mode, 'rewrite:enhance_break')) {
    rewrite('/a/b/c.txt? k=v', 'enhance_break')
}
The URI and parameters of the back-to-origin request are rewritten to /a/b/c.txt? k=v

if and($arg_mode, eq($arg_mode, 'rewrite:enhance_redirect')) {
    rewrite('/a/b/c.txt? k=v', 'enhance_redirect')
}
if and($arg_mode, eq($arg_mode, 'rewrite:enhance_redirect_301')) {
    rewrite('/a/b/c.txt? k=v', 'enhance_redirect', 301)
}
A 302 or 301 redirect to /a/b/c.txt? is performed. k=v

if and($arg_mode, eq($arg_mode, 'rewrite:break')) {
    rewrite('/a/b/c.txt', 'break')
}
The URI of the back-to-origin request is rewritten to /a/b/c.txt and the original parameters in the request remain unchanged.

if and($arg_mode, eq($arg_mode, 'rewrite:redirect')) {
    rewrite('/a/b/c.txt', 'redirect')
}
if and($arg_mode, eq($arg_mode, 'rewrite:redirect_301')) {
    rewrite('/a/b/c.txt', 'redirect', 301)
}
A 302 or 301 redirect to /a/b/c.txt is performed and the original parameters remain unchanged.

Outputs a response body and appends a newline character at the end of the output.

arg: the content of the response body. Data type: any type.

None.

say('hello')
print('byebye')
print('byebye')

Output:
hello
byebyebyebye

Outputs a response body. This function is different from the say () function. This function does not append a newline at the end of the output.

arg: the content of the response body. Data type: any type.

None.

say('hello')
print('byebye')
print('byebye')

Output:
hello
byebyebyebye

Ends the current request with the specified code. If you also set the body parameter, a response that includes the specified response body is returned.

• code: the status code to return.
• body: the response body.

None.

• Example 1

  if not($arg_key) {
      exit(403)
  }
  If a request does not include the key parameter, the request is denied and status code 403 is returned.
  
  if not($cookie_user) {
      exit(403, 'not cookie user')
  }
  If a request does not include cookie_user, the request is denied and a response that contains "not cookie user" is returned with the status code 403.
  
  if not(0) {
      exit(403)
  }
  The not (0) function returns false.
  
  if not(false) {
      exit(403)
  }
  The not (false) function returns true.

• Example 2

  pcs = capture_re($request_uri,'^/([^/]+)/([^/]+)([^?] +)\?(.*)')
  sec1 = get(pcs, 1)
  sec2 = get(pcs, 2)
  sec3 = get(pcs, 3)
  if or(not(sec1), not(sec2), not(sec3)) {
     add_rsp_header('X-TENGINE-ERROR', 'auth failed - missing necessary uri set')
     exit(403)
  }
  digest = md5(concat(sec1, sec3))
  if ne(digest, sec2) {
      add_rsp_header('X-TENGINE-ERROR', 'auth failed - invalid digest')
      exit(403)
  }