regexnginxlualua-patterns

Nginx Lua regex match first word


I try to convert regex into Lua language, from

([a-zA-Z0-9._-/]+)

to

^%w+?([_-]%w+)

I want to make match first word with '-' and '_':

mar_paci (toto totot)
toi-re/3.9
pouri marc (sensor)
Phoenix; SAGEM

The result:

marc_paci
toi-re
pouri marc
Phoenix

The code used:

value = string.match(ngx.var.args, "^%w+?([_-]%w+)")

In the ^%w+?([_-]%w+) regex, I added the ? character for an optional string.


Solution

  • You can use

    ^[%w%s_-]*%w
    

    It matches

    • ^ - start of string
    • [%w%s_-]* - zero or more alphanumerics, whitespaces, _ or hyphens
    • %w - an alphanumeric char.

    See the Lua demo:

    local function extract(text)
        return string.match(text, "^[%w%s_-]*%w")
    end
     
    print(extract("mar_paci (toto totot)"))
    -- => mar_paci
    print(extract("toi-re/3.9"))
    -- => toi-re