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    CDN:Dictionary functions

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    CDN:Dictionary functions

    Last Updated:Mar 20, 2024

    This topic describes the syntax, features, parameters, and return values of dictionary functions. This topic also provides examples of these functions.

    set

    This function sets key-value pairs in a dictionary specified by the d parameter. The following table describes the details about this function.

    Item

    Description

    Syntax

    set(d, k, v)

    Parameters

    • d: the name of the dictionary.

    • k: the key. Data type: any type.

    • v: the value. Data type: any type.

    Examples

    • Example 1: 

      outer_keys=['e66fd4aa-f281-472f-b919-fc7e7474****', '66fee78d-1887-42ec-9119-a9b50b7f****']
say(concat('keys[1]=', get(outer_keys, 1)))
say(concat('keys[2]=', get(outer_keys, 2)))

inner_keys=[]
set(inner_keys, 'dev', '243390eb-00b7-4551-a6b8-021bb34d****')
set(inner_keys, 'zeus', '4747d33b-12b0-45e6-ac10-a8e191d6****')

def echo_each(k, v, u) {
    s = concat('keys[', k, ']=', v)
    say(s)
}
foreach(inner_keys, echo_each, [])

    • Example 2 

      d_inner = []
set(d_inner, 'name', 'inner dsl')

d_outer = []
set(d_outer, 'dictA', d_inner)

v = get(d_outer, 'dictA')
if v {
    v = get(v, 'name')
    if v {
        add_rsp_header('X-DSL-NESTED-DICT', v)
    }
}

    Return values

    Returns a value of true. In this example, the following values are returned:

    • Example 1

      keys[1]=e66fd4aa-f281-472f-b919-fc7e7474****
keys[2]=66fee78d-1887-42ec-9119-a9b50b7f****
keys[dev]=243390eb-00b7-4551-a6b8-021bb34d****
keys[zeus]=4747d33b-12b0-45e6-ac10-a8e191d6****

    • Example 2: A response header is added. 

      X-DSL-NESTED-DICT: inner dsl

    get

    This function retrieves the value (v) that corresponds to a key (k) from a dictionary (d). The following table describes the details about this function.

    Item

    Description

    Syntax

    get(d, k)

    Parameters

    • d: the name of the dictionary.

    • k: the key. Data type: any type.

    Examples

    outer_keys=['e66fd4aa-f281-472f-b919-fc7e7474****', '66fee78d-1887-42ec-9119-a9b50b7f****']
say(concat('keys[1]=', get(outer_keys, 1)))
say(concat('keys[2]=', get(outer_keys, 2)))

inner_keys=[]
set(inner_keys, 'dev', '243390eb-00b7-4551-a6b8-021bb34d****')
set(inner_keys, 'zeus', '4747d33b-12b0-45e6-ac10-a8e191d6****')

def echo_each(k, v, u) {
    s = concat('keys[', k, ']=', v)
    say(s)
}
foreach(inner_keys, echo_each, [])

    Return values

    If the function succeeds, the value that corresponds to the specified key is returned. Otherwise, a value of false is returned. In this example, the following values are returned:

    keys[1]=e66fd4aa-f281-472f-b919-fc7e7474****
keys[2]=66fee78d-1887-42ec-9119-a9b50b7f****
keys[dev]=243390eb-00b7-4551-a6b8-021bb34d****
keys[zeus]=4747d33b-12b0-45e6-ac10-a8e191d6****

    foreach

    Notes on this function:

    • This function traverses elements in a dictionary (d) and calls a callback function (f) for each element.

    • Set the f parameter in the syntax of f(key, value, user_data).

    • When the f() function returns false, the foreach() loop ends.

    The following table describes the details about this function.

    Item

    Description

    Syntax

    foreach(d, f, user_data)

    Parameters

    • d: the name of the dictionary.

    • f: the callback function.

    • user_data: the user data that you want to transmit. Data type: dictionary.

    Examples

    • Example 1: 

      outer_keys=['e66fd4aa-f281-472f-b919-fc7e7474****', '66fee78d-1887-42ec-9119-a9b50b7f****']
say(concat('keys[1]=', get(outer_keys, 1)))
say(concat('keys[2]=', get(outer_keys, 2)))

inner_keys=[]
set(inner_keys, 'dev', '243390eb-00b7-4551-a6b8-021bb34d****')
set(inner_keys, 'zeus', '4747d33b-12b0-45e6-ac10-a8e191d6****')

def echo_each(k, v, u) {
    s = concat('keys[', k, ']=', v)
    say(s)
}
foreach(inner_keys, echo_each, [])

    • Example 2

      Prints the first two M3U8 slices and ends the foreach loop. 

      def echo_each(k, v, u) {
    say(v)

    if match_re(v, '.*ts') {
        ts_cnt = get(u, 'ts_cnt')
        ts_cnt = add(ts_cnt, 1)
        set(u, 'ts_cnt', ts_cnt)

        if ge(ts_cnt, 2) {
            return false
        }
    }
}

m3u8 = ''
m3u8 = concat(m3u8, '#EXTM3U8', '\n')
m3u8 = concat(m3u8, '#EXT-X-MEDIA-SEQUENCE:14065****\n')
m3u8 = concat(m3u8, '#EXT-X-TARGETDURATION:10\n')
m3u8 = concat(m3u8, '#EXTINF:8,\n')
m3u8 = concat(m3u8, 'http://***.cn/cache/289_/seg0/index140651514_1406****.ts\n')
m3u8 = concat(m3u8, '#EXTINF:9,\n')
m3u8 = concat(m3u8, 'http://***.cn/cache/289_/seg0/index140651514_1406****.ts\n')
m3u8 = concat(m3u8, '#EXTINF:10,\n')
m3u8 = concat(m3u8, 'http://***.cn/cache/289_/seg0/index140651514_1406****.ts\n')

lines = split(m3u8, '\n')
u = []
set(u, 'ts_cnt', 0)
foreach(lines, echo_each, u)

    Return values

    Returns a value of true. In this example, the following values are returned:

    • Example 1

      keys[1]=e66fd4aa-f281-472f-b919-fc7e7474****
keys[2]=66fee78d-1887-42ec-9119-a9b50b7f****
keys[dev]=243390eb-00b7-4551-a6b8-021bb34d****
keys[zeus]=4747d33b-12b0-45e6-ac10-a8e191d6****

    • Example 2

      #EXTM3U8
#EXT-X-MEDIA-SEQUENCE:140651513
#EXT-X-TARGETDURATION:10
#EXTINF:8,
http://***.cn/cache/289_/seg0/index140651514_1406****.ts
#EXTINF:9,
http://***.cn/cache/289_/seg0/index140651514_1406****.ts

    del

    This function deletes key-value pairs from a dictionary (d). The following table describes the details about this function.

    Item

    Description

    Syntax

    del(d, k)

    Parameters

    • d: the name of the dictionary.

    • k: the key. Data type: any type.

    Examples

    var_a = []
set(var_a, 'note_a', 'note a info')
if get(var_a, 'note_a') {
    add_rsp_header('X-RESPOND-OUTPUT', 'found var_a key', true)
} else {
    add_rsp_header('X-RESPOND-OUTPUT', 'del var_a key', true)
}
del(var_a, 'note_a')
if get(var_a, 'note_a') {
    add_rsp_header('X-RESPOND-OUTPUT', 'found var_a key', true)
} else {
    add_rsp_header('X-RESPOND-OUTPUT', 'del var_a key', true)
}

    Return values

    Returns a value of true. In this example, the following values are returned:

    X-RESPOND-OUTPUT: found var_a key
X-RESPOND-OUTPUT: del var_a key