string/append and base64

cormullion · Post by **cormullion** » Thu Oct 05, 2006 9:59 pm

Not sure what I'm doing, but I don't understand why these two give different results:

(println (append "AUTH PLAIN " (base64-enc (append "\000" "user.name" "\000" "password"))))
(println (append "AUTH PLAIN " (base64-enc (string "\000" "user.name" "\000" "password"))))

AUTH PLAIN AHVzZXIubmFtZQBwYXNzd29yZA==
AUTH PLAIN dXNlci5uYW1lcGFzc3dvcmQ=

I'm adapting SMTP.lsp to do authorization, but why should string be different? Is it a Unicode thing?

Lutz · Post by **Lutz** » Fri Oct 06, 2006 12:52 am

'append' works on binary (non displayable ASCII). 'string' does not, it will take a \000 as a string terminator, like 'print' and 'println' which are based on 'string':

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> (string "\000")
""
> (append "\000")
"\000"
>

Lutz

ps: see docs for 'append' and 'string'. Do we need a chapter/paragraph explaining this, perhaps in
http://newlisp.org/downloads/newlisp_ma ... l#type_ids ?

cormullion · Post by **cormullion** » Fri Oct 06, 2006 7:54 am

Thanks, Lutz. I remember now. I was confusing myself partly by working in a file rather than directly in the terminal. I was trying to decode a string:

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(set 's (base64-dec "AHVzZXIubmFtZQBwYXNzd29yZA=="))
(println s)

- of course println returns the value correctly ("\000user.name\000password") but it doesn't display anything.

For some reason, the AUTH part of SMTP uses these zero terminators so I got myself well confused...

What's a good way of displaying the contents of strings like this in a log file?

Lutz · Post by **Lutz** » Fri Oct 06, 2006 11:34 am

Use plain 'replace' without the regular expressions option:

Code: Select all

(replace "\000" (base64-dec "AHVzZXIubmFtZQBwYXNzd29yZA==") " ")
=> " user.name password"

to change the "\000" to a space or some other character.

Lutz

cormullion · Post by **cormullion** » Fri Oct 06, 2006 1:49 pm

Thanks! In fact. I'll replace it with "\\000" just so that I know what's happening...