This topic describes examples of EdgeScript rules that can be applied to specific scenarios.

Local authentication for FLV pull

The following example shows how to use local authentication for FLV pull:
  • Requirements
    For .flv requests, the requirements for hotlink protection are defined as follows:
    • Rule 1: If the request does not contain the sign or expires parameter, the CDN node returns a 403 status code and adds the X-AUTH-MSG response header to indicate the cause of failure.
    • Rule 2: The t parameter specifies the expiration time. If the t parameter value is earlier than the current time, the CDN node returns a 403 status code and adds the X-AUTH-MSG response header to indicate the cause of failure.
    • Rule 3: The value of md5 matches the value of sign. If both values do not match, the CDN node returns a 403 status code. The response header X-AUTH-MSG is added to indicate the cause of failure.
  • Parameters
    • expires: the URL parameter, which defines the expiration time (Unix timestamp). This parameter value must be greater than the current server time.
    • sign: the signature field. Rule to generate this field is: sign=md5($uri + $expires + $secret).
  • EdgeScript rule
    secret='abc'
    
    if eq(substr($uri, -4, -1), '.flv') {
    
        if or(not($arg_sign), not($arg_expires)) {
            add_rsp_header('X-AUTH-MSG', 'auth failed - missing necessary arg')
            exit(403)
        }
    
        t = tonumber($arg_expires)
        if gt(now(), t) {
            add_rsp_header('X-AUTH-MSG', 'auth failed - expired url')
            exit(403)
        }
    
        digest = md5(concat($uri, $arg_expires, secret))
        if ne(digest, $arg_sign) {
            add_rsp_header('X-AUTH-MSG', 'auth failed - invalid sign')
            exit(403)
        }
    }

User-Agent blacklist for FLV pull

The following example shows how to use the User-Agent blacklist for FLV pull:
  • Requirements

    The User-Agent blacklist feature.

    The hyphens (-) in the request header need to be replaced with underscores (_). For example, X-USER-ID is replaced with x_user_id.

  • EdgeScript rule
    if eq(substr($uri, -4, -1), '.flv') {
    
        blacklist = []
        set(blacklist, 'black1', 1)
        set(blacklist, 'black2', 1)
    
        ua = req_header('user_agent')
    
        if eq(get(blacklist, ua), 1) {
            exit(403)
        }
    }

FLV streaming prohibition by IP address

The following example shows how to use the IP address blacklist for FLV pull:
  • Requirements

    Prohibits users originated from Singapore, Taiwan (China), Zhuhai, and China Telecom from streaming FLV content.

    Note For more information about country codes, see Appendix.
  • EdgeScript rule
    if eq(substr($uri, -4, -1), '.flv') {
        c_country = client_country()
        c_region = client_region()
        c_city = client_city()
        c_isp = client_isp()
        
        if eq(c_country, 'SG') {
            exit(403)
        }
      
        if eq(c_region, 'TW_01') {
            exit(403)
        }
      
        if eq(tonumber(c_city), 440400) {
            exit(403)
        }
      
        if eq(tonumber(c_isp), 100017) {
            exit(403)
        }
    }

URI rewrite for FLV pull

The following example shows how to use URI rewrite for FLV pull:
  • Requirements

    Add a suffix to the URI based on the pattern parameter. Example:

    pattern = 1, uri = /test/live.flv --> /test/live1.flv

  • EdgeScript rule
    if eq(substr($uri, -4, -1), '.flv') {
        if $arg_pattern {
            dst = concat(substr($uri, 1, -5), $arg_pattern, '.flv')
            rewrite(dst, 'break')
        }
    }

Customize the authentication logic

The following example shows custom authentication algorithms:
  • Use scenario
    • Request URL format: /path/digest/?.ts?key=&t=.
    • For .ts requests, the requirements for customizing hotlink protection are:
      • Rule 1: If the request does not contain the t or key parameter, the CDN edge node returns the HTTP 403 status code and adds the X-AUTH-MSG response header to indicate the cause of failure.
      • Rule 2: The t parameter specifies the expiration time. If the specified t parameter is earlier than the current time, the CDN edge node returns the HTTP 403 status code and adds the X-AUTH-MSG response header to indicate the cause of failure.
      • Rule 3: The CDN edge node compares the md5 parameter with the digest parameter. If md5 does not match digest, the CDN edge node returns the HTTP 403 status code.

        Value format of the md5 parameter: Private key + Path + Filename.extension.

  • 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)
        }
    
    }

Customize request headers and response headers

The following example shows automatic file renaming:

Example:

add_rsp_header('Content-Disposition', concat('attachment;filename=', tochar(34), filename, tochar(34)))
Note
  • You can add the response header Content-Disposition:attachment to HTTP responses to have the message body automatically downloaded. In addition, if the response carries the filename parameter, it is automatically renamed filename. If the response does not carry the filename parameter, the default name is used.
  • The value for the filename parameter is enclosed in a pair of double quotation marks (""). The string "34" is the ASCII string for double quotation marks. It can be converted back to the quotation mark string ("") by using the tochar function.

Output:

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

Script:

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

Customize rewrites and redirects

The following examples show how to customize rewrites and redirects:
  • Rewrite a URI.
    • Use scenario

      Enable Alibaba Cloud CDN to rewrite /hello to /index.html. As a result, the URI of the back-to-origin request is changed to /index.html and the parameters remain unchanged.

    • Script
      if match_re($uri, '^/hello$') {
          rewrite('/index.html', 'break')
      }
  • Rewrite a file extension.
    • Use scenario

      Enable Alibaba Cloud CDN to rewrite /1.txt to /1.<URL parameter type> on CDN edge nodes. As a result, the file extension is replaced by the value of the type parameter in the request URL. For example, /1.txt?type=mp4 is changed to /1.mp4?type=mp4 before the request is redirected to the origin server. Then, the retrieved content is cached on CDN edge nodes.

    • Script
      if and(match_re($uri, '^/1.txt$'), $arg_type) {
           rewrite(concat('/1.', $arg_type), 'break')
      }
  • Convert a file extension to lowercase letters.
    • Use scenario

      Convert URI strings to lowercase letters.

    • Script
      pcs = capture_re($uri, '^(.+%.)([^.]+)')
      section = get(pcs, 1)
      postfix = get(pcs, 2)
      
      if and(section, postfix) {
          rewrite(concat(section, lower(postfix)), 'break')
      }
  • Add a URI prefix.
    • Use scenario

      Enable Alibaba Cloud CDN to rewrite ^/nn_live/(.*) to /3rd/nn_live/$1 on CDN edge nodes.

    • Script
      pcs = capture_re($uri, '^/nn_live/(.*)')
      sec = get(pcs, 1)
      
      if sec {
           dst = concat('/3rd/nn_live/', sec)
           rewrite(dst, 'break')
      }
  • Perform a 302 redirect
    • Use scenario

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

    • Script
      if eq($uri, '/') {
          rewrite('/app/movie/pages/index/index.html', 'redirect')
      }
  • Perform a 302 redirect to HTTPS URIs
    • Use scenario
      Redirect the following URIs that match the ^/$ root directory to https://rtmp.cdnpe.com/index.html. You can specify the final URI as needed.
      • http://demo.aliyundoc.com
      • https://demo.aliyundoc.com
    • Script
      if eq($uri, '/') {
          rewrite('https://demo.aliyundoc.com/index.html', 'redirect')
      }