Find substring between specific characters

Question

I am unfamiliar with Lua language and a I would like your help. I am trying to receive some values through POST and the values is something like that:

pwd = password
ssid = ssid_name

---

swstat={string.find(payload,"pwd=")}
swstat1={string.find(payload,"ssid=")}
if swstat[2]~=nil then
    pass=string.sub(payload,swstat[2]+1,#payload)
    ssid=string.sub(payload,swstat1[2]+1,#payload)
    print("Password: "..pass)
    print("SSID: "..ssid)
end

The actual result of the above code is ( am sending through a web browser the ssid=htc and password=fr):

Password: fr
SSID: htc&pwd=fr

I would like to have in a string the password only and in another string the ssid. So my idea is to search into string with the following logic: ssid = find in string the sub string which is between "ssid=" and ("&" or end of string) pwd = find in string the sub string which is between "pwd=" and ("&" or end of string)

Answer 1

Since payload is a valid query string format, you can store related information inside a table:

local tData = {}
for sParam, sValue in payload:gmatch "([^=&]+)=([^=&]+)" do
    tData[sParam:lower()] = sValue
end

Now, you'll have the information inside the tData table:

tData.pwd     -- will have fr
tData.ssid    -- will have htc