Edge Security Acceleration:String functions

• s: the string that you want to extract.
• i: the position to start extraction in the source string, counting from 1. A value of -1 specifies the rightmost character of the string. Data type: integer.
• j: the position to end extraction in the source string, counting from 1. A value of -1 specifies the rightmost character of the string. Data type: integer.

//Note: The two methods that are used to determine whether a file is an M3U8 file.
if eq(substr($uri, -5, -1), '.m3u8') {
    say(concat($uri, ' is .m3u8'))
}

uri_len = len($uri)
if eq(substr($uri, -5, uri_len), '.m3u8') {
    say(concat($uri, ' is .m3u8'))
}

//Note: The two methods that are used to determine whether a file is an M3U8 file.
if eq(substr($uri, -5, -1), '.m3u8') {
    say(concat($uri, ' is .m3u8'))
}

uri_len = len($uri)
if eq(substr($uri, -5, uri_len), '.m3u8') {
    say(concat($uri, ' is .m3u8'))
}

mystr = 'Hello, Dsl'                                                                                                                                                                                   
say(upper(mystr))                                                                                                                                                                                      
say(lower(mystr)) 
//Output:
//HELLO,DSL
//hello, dsl

mystr = 'Hello, Dsl'                                                                                                                                                                                   
say(upper(mystr))                                                                                                                                                                                      
say(lower(mystr)) 
//Output:
//HELLO,DSL
//hello, dsl

//Note: The two methods that are used to determine whether a file is an M3U8 file.
if eq(substr($uri, -5, -1), '.m3u8') {
    say(concat($uri, ' is .m3u8'))
}

uri_len = len($uri)
if eq(substr($uri, -5, uri_len), '.m3u8') {
    say(concat($uri, ' is .m3u8'))
}

say(byte('a'))
say(byte('A'))
//Output: 97
//65

• s: the string that you want to match. Data type: string.
• p: the regular expression for matching. Data type: string.
• o: the regular expression engine. Data type: string. This parameter is optional.
  • empty value: specifies that this function is case-sensitive.
  • i: specifies that this function is not case-sensitive.

url = concat('http://', $host, $uri)
m1 = match_re(url, 'http://.*\.example\.com/.*', 'i')
m2 = match_re(url, '^http://.*\.aliyundoc\.com\.cn/.*\.d\\.html(\?.*)?$')
m3 = match_re(url, '^http://.*.demo.aliyundoc/.*\.d\.html(\?.*)?$')
m4 = match_re(url, '^http://.*\.aliyundoc\.com\.cn/zt_d/')
m5 = match_re(url, '^http://learn.aliyundoc.com.cn/zt_d/we2015/?$')
m6 = match_re($args, 'from=wap1$')
m7 = match_re($args, 'from=comos1$')

if and(m1, or(m2, m3), not(m4), not(m5), or(not(m6), not(m7))) {                                                                                                                                       
    add_rsp_header('USER-DEFINED-1', 'hit1')                                                                                                                                                           
    add_rsp_header('USER-DEFINED-2', 'hit2')                                                                                                                                                         

• s: the string that you want to match. Data type: string.
• p: the regular expression for matching. Data type: string.
• init: the position to start matching, counting from 1. Data type: integer.

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)
}                                                                                                                                                      

• subject: the string that you want to match. Data type: string.
• regex: the regular expression. Data type: string.
• replace: the string for replacement. Data type: string.
  You can specify the replace parameter by using the matching substrings.

  • $0: specifies all substrings that match regex.
  • $N: specifies the substring that matches the Nth parenthesized subexpression () of regex.
• option: the regular expression engine. Data type: string. This parameter is optional.

subject = 'Hello, Es'
regex = '([a-zA-Z])[a-z]+'
replace = '[$0,$1]'
add_rsp_header('X-DEBUG-GSUB-RE', gsub_re(subject, regex, replace))         
//Output:
//X-DEBUG-GSUB-RE: [Hello,H], [Es,E]                                                                                                                                      

• s: the string that you want to split. Data type: string.
• sep: the separator that is used to split the string. Data type: string.

if $arg_from {
    t = split($arg_from, ',')
    if get(t, 1) {
        say(concat('[1]=', get(t, 1)))
    }
    if get(t, 2) {
        say(concat('[2]=', get(t, 1)))
    }
}         
//Request: ?from=xx1,xx2,xx3  
//Response: [1]=xx1
//[2]=xx1                                                                                                                                   

• s: the string that you want to split. Data type: string.
• sep: the separator that is used to split the string. Data type: string.

def echo_each(k, v, u) {
    s = concat(k, '=', v, ' u=', get(u, 1))
    say(s) 
}
if $arg_from {
    t = split_as_key($arg_from, ',')
    foreach(t, echo_each, ['hi,dsl'])
}    
//Request: ?from=xx1,xx2,xx3  
//Response: xx2=xx2 u=hi,dsl
//xx1=xx1 u=hi,dsl
//xx3=xx3 u=hi,dsl                                                                                                                                   

digest = sha1('xxxx')
add_rsp_header('X-DSL-TOHEX', tohex(digest))    

//Note: A response header is added.
//X-DSL-TOHEX: 4ad583af22c2e7d40c1c916b2920299155a46464                                                                                                                                     

s = tostring(123)
add_rsp_header('X-DSL-TOSTRING', s)  

//Note: A response header is added.
//X-DSL-TOSTRING: 123                                                                                                                            

• Converts one or more internal integers (ASCII values) to a string. For example, 48 corresponds to the character "0".
• The length of the returned string is based on the number of specified parameters.

add_rsp_header('X-DSL-TOCHAR', tochar(97))
add_rsp_header('X-DSL-TOCHAR', tochar(97, 98), true)
//Output: A response header is added.
//X-DSL-TOCHAR: a
//X-DSL-TOCHAR: ab

if $arg_filename {
    hn = 'Content-Disposition'
    add_rsp_header('Content-Disposition', concat('attachment;filename=', tochar(34), filename, tochar(34)))
    add_rsp_header(hn, hv)
}     
//Output: A response header is added.
//Content-Disposition: attachment;filename="The value of the filename parameter"                                                                                                                                    

say(reverse('hello'))

#olleh

• s: the string that you want to search.
• substr: the substring that you want to search.
• pos: the position where the search starts. Data type: numeric. This parameter is optional. You can specify a negative integer. The default value is 1.

• Returns an array if the specified substring is found.
  • Index 1 indicates the position where the search starts.
  • Index 2 indicates the position where the search ends.
• Returns an empty array if the specified substring is not found.

 str = 'hello dsl'
 add_rsp_header('string-find()-start', tostring(get(find(str, 'dsl'), 1)))
 str = 'hello dsl 12'
 add_rsp_header('string-find()-end', tostring(get(find(str, 'dsl'), 2)))
 str = 'hello dsl'
 add_rsp_header('string-find()-tail-start', tostring(get(find(str, 'dsl', -6), 1)))
 str = 'hello dsl 12'
 add_rsp_header('string-find()-tail-end', tostring(get(find(str, 'dsl', -6), 2)))

string-find()-start:7
string-find()-end:9
string-find()-tail-start:7
string-find()-tail-end:9

• fmt: the string type. This parameter specifies a format string.
• The variable number of parameters: any type.

say(concat('format:', format('%%%s$%.2s$%s$%c$%d$%2.2f$%.2o$%x$%X', 'format', 3.1415926, true, 95, 3.1415926, 3.1415926, 3.1415926, 10, 10)))

format:%format$3.$true$_$3$3.14$03$a$A

say(concat('tobin:', tobin('2F2F')))

tobin://

• s: the string.
• loc: the default value is both. This parameter is optional. Valid values:
  • both: removes the whitespace characters before and after the string.
  • left: removes only the whitespace characters before the string.
  • right: removes only the whitespace characters after the string.

say(concat('trim():', trim(' abcd ')))
say(concat('trim(left):', trim(' abcd ', 'left')))
say(concat('trim(right):', trim(' abcd ', 'right')))

trim():abcd
trim(left):abcd
trim(right): abcd