Convert String to Hash


#1

Hi,

I get a string inputted in my program, which I convert to a hash-like
string, like:

sql = ‘“table_alias” => [],“original_string” => “select * from table”’

The string has the form of a hash, now I would like to convert this
string to an actual hash. I tried it like:

test = Hash[sql]
or
test = Hash.

but I get the following error:
test2.rb:2:in `[]’: odd number of arguments for Hash (ArgumentError)
from test2.rb:2

When I do it like,

test = Hash.new
test = sql

test becomes a String and is no longer a Hash.

Is there an easy way to convert my hash-like string to an actual hash?
Thanks for any help.

Kind regards,

Nick


#2

Nick S. scribbled on Thursday 09 Mar 2006 12:52:

test = Hash[sql]
test = sql

test becomes a String and is no longer a Hash.

Is there an easy way to convert my hash-like string to an actual hash?
Thanks for any help.

Kind regards,

Nick

Hi Nick,

no, you can’t pass it to Hash.new directly, you’d have to write a parser
for
it yourself. If you’re feeling lucky, you can use eval() to do that.

takes cover from flying bananas and such

Bernhard


#3

Use YAML.


#4

Nick S. wrote:

Hi,

I get a string inputted in my program, which I convert to a hash-like
string, like:

sql = ‘“table_alias” => [],“original_string” => “select * from table”’

The simplest, although slow:

sql = ‘“table_alias” => [],“original_string” => “select * from table”’
hash = eval(’{’+sql+’}’)

lopex


#5

throws banana ad Bernhard

no no no don’t eval user supplied strings you are asking to be hacked :slight_smile:


#6

Rob Pitt scribbled on Thursday 09 Mar 2006 13:01:

throws banana ad Bernhard

no no no don’t eval user supplied strings you are asking to be hacked :slight_smile:

Well, in certain local-only low-security scenarios it might be of use. I
wouldn’t know where Nick takes his strings from. :}


#7

Hi,

thanks for all the replies. I used the eval method and it worked!! The
string doesn’t come directly from user input. It first goes through a
Perl sql parser and then into my program. So hopefully this doesn’t
introduce any security issues, but I will be aware of the possibility.
Thanks for the help.

Kind regards,

Nick

Bernhard ‘elven’ Stoeckner wrote:

Rob Pitt scribbled on Thursday 09 Mar 2006 13:01:

throws banana ad Bernhard

no no no don’t eval user supplied strings you are asking to be hacked :slight_smile:

Well, in certain local-only low-security scenarios it might be of use. I
wouldn’t know where Nick takes his strings from. :}


#8

Argh!

Please stop telling people to eval user supplied strings!

The ONLY time it is safe to use eval is if all the contents are
generated by you and NONE of the components come from user input.

It looks here like original_string comes from user.

Imagine if I supplied this:

" => ‘lame’; rm -rf / #