Server Load Balancer:AScript common scenarios

Requirements

• Request URL format: /path/digest/?.tskey=&t=.

• For .ts requests, the requirements for configuring custom hotlink protection are:

  • Rule 1: If the request does not contain the t or key parameter, the HTTP 403 status code is returned and the X-AUTH-MSG response header is added to indicate the cause of failure.

  • Rule 2: The t parameter specifies the absolute expiration time. If the time specified by t is earlier than the current time, the HTTP 403 status code is returned and the X-AUTH-MSG response header is added to indicate the cause of failure.

  • Rule 3: Compare the md5 value with the digest value. If the md5 value does not match the digest value, the HTTP 403 status code is returned.

    Value format of the md5 value: Private key + Path + File name.extension.

Sample script

if eq(substr($uri, -3, -1), '.ts') {

  if or(not($arg_t), not($arg_key)) {
       add_rsp_header('X-AUTH-MSG', 'auth failed - missing necessary arg')
       exit(403)
   }

   t = tonumber($arg_t)
   if not(t) {
       add_rsp_header('X-AUTH-MSG', 'auth failed - invalid time')
       exit(403)
   }

   if gt(now(), t) {
       add_rsp_header('X-AUTH-MSG', 'auth failed - expired url')
       exit(403)
   }

    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-AUTH-MSG', 'auth failed - malformed url')
        exit(403)
    }

    key = 'b98d643a-9170-4937-8524-6c33514bbc23'
    signstr = concat(key, sec1, sec3)
    digest = md5(signstr)
    if ne(digest, sec2) {
        add_rsp_header('X-AUTH-DEBUG', concat('signstr: ', signstr))
        add_rsp_header('X-AUTH-MSG', 'auth failed - invalid digest')
        exit(403)
    }

}

Requirements: If a request carries the User-Agent header that starts with ijkplayer or Ysten, the HTTP status code 403 is returned.

Sample script

if and($http_user_agent, match_re($http_user_agent, '^(ijkplayer|Ysten).*$')) {
    add_rsp_header('X-BLOCKLIST-DEBUG', 'deny')
    exit(403)
}

Requirements: If the Referer header of a request is not http[s]://***alibaba.com***, the HTTP 403 status code is returned.

Sample script

if and($http_referer, match_re($http_referer, '^(http|https)://(.)+\.alibaba\.com.*$')) {
    return true
}

add_rsp_header('X-WHITELIST-DEBUG', 'missing')
exit(403)

Requirements: If a request is sent from 127.0.0.1 or 10.0.0.1, the HTTP 403 status code is returned.

Sample script

if match_re($remote_addr, '127.0.0.1|10.0.0.1') {
    add_rsp_header('X-IPBLOCK-DEBUG', 'hit')
    exit(403)
}

Requirements: If the filename parameter is specified, the file is automatically renamed the value specified by the filename parameter. If the filename parameter is not specified, the default filename is used.

Sample script

if $arg_filename {
  hn = 'Content-Disposition'
    hv = concat('attachment;filename=', $arg_filename)
    add_rsp_header(hn, hv)
}

Example:

add_rsp_header('Content-Disposition', concat('attachment;filename=', tochar(34), filename, tochar(34)))

Output:

Content-Disposition: attachment;filename="monitor.apk"

Requirements: Overwrite the response header Content-Typ.

Sample script

add_rsp_header('Content-Type', 'audio/mpeg')

Requirements: Rewrite /hello in user requests to /index.html. As a result, the URI of the back-to-origin request and the cached URI are changed to /index.html. Other parameters remain unchanged.

Sample script

if match_re($uri, '^/hello$') {
    rewrite('/index.html', 'break')
}

Requirements: Rewrite /1.txt to /1.<URL parameter type>. For example, /1.txt?type=mp4 can be rewritten to /1.mp4?type=mp4 in back-to-origin requests and cached.

Sample script

if and(match_re($uri, '^/1.txt$'), $arg_type) {
     rewrite(concat('/1.', $arg_type), 'break')
}

Requirements: Convert URI strings to lowercase letters.

Sample script

pcs = capture_re($uri, '^(.+\.)([^.]+)')
section = get(pcs, 1)
postfix = get(pcs, 2)

if and(section, postfix) {
    rewrite(concat(section, lower(postfix)), 'break')
}

Requirements: Rewrite ^/nn_live/(.*) in user requests to /3rd/nn_live/$1.

Sample script

pcs = capture_re($uri, '^/nn_live/(.*)')
sec = get(pcs, 1)

if sec {
     dst = concat('/3rd/nn_live/', sec)
     rewrite(dst, 'break')
}

Requirements: Perform a 302 redirect from the / root directory to /app/movie/pages/index/index.html.

Sample script

if eq($uri, '/') {
    rewrite('/app/movie/pages/index/index.html', 'redirect')
}

Requirements

Sample script

if eq($uri, '/') {
    rewrite('https://aliyun.com', 'redirect')
}