I have code that prints to stdout (using puts and/or print).
I'm loading the code from a file (pretty much the way rake handles rakefiles) and would like to capture the output from the loaded code.
I don't want to redirect stdout into a file or anywhere else, I need the output in a string.
---file1.rb
puts "Output of meaningful code omitted"
---loader.rb
begin
###do some magic to get the stdout from this point on into a string
load file1.rb
###do some more magic to put stdout back where it was.
end
Has anyone a solution for this?
(Now that I think of it would StringIO do for stdout redirection?)
Cheers,
V.-
I have code that prints to stdout (using puts and/or print).
I'm loading the code from a file (pretty much the way rake handles
rakefiles) and would like to capture the output from the loaded code.
I don't want to redirect stdout into a file or anywhere else, I need the
output in a string.
---file1.rb
puts "Output of meaningful code omitted"
---loader.rb
begin
###do some magic to get the stdout from this point on into a string
load file1.rb
###do some more magic to put stdout back where it was.
end
Has anyone a solution for this?
You can use popen but then your code is in another process.
(Now that I think of it would StringIO do for stdout redirection?)
Yes, but you then must explicitely use a receiver with those puts
statements as Kernel.puts still sends to $DEFOUT.
I have code that prints to stdout (using puts and/or print).
I'm loading the code from a file (pretty much the way rake handles
rakefiles) and would like to capture the output from the loaded code.
I don't want to redirect stdout into a file or anywhere else, I need the
output in a string.
---file1.rb
puts "Output of meaningful code omitted"
---loader.rb
begin
###do some magic to get the stdout from this point on into a string
load file1.rb
###do some more magic to put stdout back where it was.
end
How about do it this way:
s = `ruby file1.rb` , you don't need to load file1.rb in .
###do some magic to get the stdout from this point on into a string
All you have to do is assign a different IO Object to the global
$stdout variables and Kernel.puts will write to that IO object.
The `real` standard out of the process will be available in the STDOUT
constant, in case you need definate access to it, though you'd
probably want to save a copy of the original value of $stdout, you
never know...
old_stdout=$stdout
$stdout=File.new(...)
···
#
# Do a bunch of stuff that shouldn't log to the console
#
$stdout=old_stdout # everything back to normal...
Quoting damphyr@freemail.gr, on Wed, May 17, 2006 at 07:49:34PM +0900:
I have code that prints to stdout (using puts and/or print).
I'm loading the code from a file (pretty much the way rake handles
rakefiles) and would like to capture the output from the loaded code.
I don't want to redirect stdout into a file or anywhere else, I need the
output in a string.
---file1.rb
puts "Output of meaningful code omitted"
---loader.rb
begin
###do some magic to get the stdout from this point on into a string
load file1.rb
###do some more magic to put stdout back where it was.
end
Has anyone a solution for this?
(Now that I think of it would StringIO do for stdout redirection?)
I have code that prints to stdout (using puts and/or print).
I'm loading the code from a file (pretty much the way rake handles
rakefiles) and would like to capture the output from the loaded code.
I don't want to redirect stdout into a file or anywhere else, I need the
output in a string.
---file1.rb
puts "Output of meaningful code omitted"
---loader.rb
begin
###do some magic to get the stdout from this point on into a string
load file1.rb
###do some more magic to put stdout back where it was.
end
Has anyone a solution for this?
You can use popen but then your code is in another process.
(Now that I think of it would StringIO do for stdout redirection?)
Yes, but you then must explicitely use a receiver with those puts
statements as Kernel.puts still sends to $DEFOUT.
Yes, but I can change Kernel#puts
These files are tests, written using a simple DSL and then run just like rake runs it's rakefiles.
So I am loath to require receivers for puts or any other logging facility (I am the only one in my project comfortable with Ruby, although everyone agrees that it saves them a lot of time and trouble).
popen was my obvious choice (it's already in use in this whole mess) but I was wondering if there was another way.
Oh, well.
Cheers,
V.-
I have code that prints to stdout (using puts and/or print).
I'm loading the code from a file (pretty much the way rake handles
rakefiles) and would like to capture the output from the loaded code.
I don't want to redirect stdout into a file or anywhere else, I need the
output in a string.
---file1.rb
puts "Output of meaningful code omitted"
---loader.rb
begin
###do some magic to get the stdout from this point on into a string
load file1.rb
###do some more magic to put stdout back where it was.
end
# Create a string object to receive the output.
dest = ''
# Add a write method to this string object.
def dest.write(data); self << data; end
old_stdout, $stdout = $stdout, dest
# Invoke code that uses puts.
# Restore stdout.
$stdout = old_stdout
···
On 5/17/06, Daniel Harple <dharple@generalconsumption.org> wrote:
2006/5/17, Damphyr <damphyr@freemail.gr>:
> I have code that prints to stdout (using puts and/or print).
> I'm loading the code from a file (pretty much the way rake handles
> rakefiles) and would like to capture the output from the loaded code.
> I don't want to redirect stdout into a file or anywhere else, I
> need the
> output in a string.
>
> ---file1.rb
> puts "Output of meaningful code omitted"
> ---loader.rb
>
> begin
> ###do some magic to get the stdout from this point on into a string
> load file1.rb
> ###do some more magic to put stdout back where it was.
> end
>
> Has anyone a solution for this?
On 5/17/06, Daniel Harple <dharple@generalconsumption.org> wrote:
2006/5/17, Damphyr <damphyr@freemail.gr>:
I have code that prints to stdout (using puts and/or print). I'm loading the code from a file (pretty much the way rake handles rakefiles) and would like to capture the output from the loaded code. I don't want to redirect stdout into a file or anywhere else, I need the output in a string.
# Add a write method to this string object.
def dest.write(data); self << data; end
How is this better than using StringIO?
IMHO, by using StringIO, you pay for something useless in this case but
maybe usefule anywhere else. I mean StringIO has many methods(e.g.
read,close,rewind) besides write , but "def dest.write....." has just
the function you want. You just pay for what you want. Isn't it better?
# Add a write method to this string object.
def dest.write(data); self << data; end
How is this better than using StringIO?
IMHO, by using StringIO, you pay for something useless in this case but
maybe usefule anywhere else. I mean StringIO has many methods(e.g.
read,close,rewind) besides write , but "def dest.write....." has just
the function you want.
You're confusing unused with useless. I almost never use Hash#index but that doesn't make it useless.
You just pay for what you want. Isn't it better?
No. Using StringIO is more robust and more maintainable than using a String with custom methods. If I want to puts or print then I have to add those methods. If I just used StringIO I won't have to do anything.
I've found that having to maintain custom code is usually more expensive than reusing what's available.
···
On May 17, 2006, at 12:10 PM, uncutstone wu wrote:
On May 17, 2006, at 5:26 AM, Mark Volkmann wrote:
--
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net
This implementation is HODEL-HASH-9600 compliant
You don't have to add a puts method to the String object in order to
have puts calls append to it. puts ends up calling write. I assume
print does the same, but I'm not sure.
···
On 5/17/06, Eric Hodel <drbrain@segment7.net> wrote:
On May 17, 2006, at 12:10 PM, uncutstone wu wrote:
> Eric Hodel wrote:
>> On May 17, 2006, at 5:26 AM, Mark Volkmann wrote:
>>>> $stdout = stdout
>>>
>>> # Add a write method to this string object.
>>> def dest.write(data); self << data; end
>>
>> How is this better than using StringIO?
>
> IMHO, by using StringIO, you pay for something useless in this case
> but
> maybe usefule anywhere else. I mean StringIO has many methods(e.g.
> read,close,rewind) besides write , but "def dest.write....." has just
> the function you want.
You're confusing unused with useless. I almost never use Hash#index
but that doesn't make it useless.
> You just pay for what you want. Isn't it better?
No. Using StringIO is more robust and more maintainable than using a
String with custom methods. If I want to puts or print then I have
to add those methods. If I just used StringIO I won't have to do
anything.
No. Using StringIO is more robust and more maintainable than using a
String with custom methods. If I want to puts or print then I have
to add those methods. If I just used StringIO I won't have to do
anything.
You don't have to add a puts method to the String object in order to
have puts calls append to it. puts ends up calling write. I assume
print does the same, but I'm not sure.
Yes, print does the same.
main.rb:
strio = ""
def strio.write(data)
self << data
end
$stdout = strio
load 'expansion.rb'
$stdout = STDOUT
puts "Get: #{strio}"
expansion.rb
print "hello"
result:
Get: hello
···
On 5/17/06, Eric Hodel <drbrain@segment7.net> wrote:
The Kernel methods have this behavior, yes, but this is not a general solution.
$ ruby
s = ''
def s.write(d) self << d; end
$stdout = s
$stdout.puts 'hi'
-:4: private method `puts' called for "":String (NoMethodError)
···
On May 17, 2006, at 1:41 PM, Mark Volkmann wrote:
On 5/17/06, Eric Hodel <drbrain@segment7.net> wrote:
> You just pay for what you want. Isn't it better?
No. Using StringIO is more robust and more maintainable than using a
String with custom methods. If I want to puts or print then I have
to add those methods. If I just used StringIO I won't have to do
anything.
You don't have to add a puts method to the String object in order to
have puts calls append to it. puts ends up calling write. I assume
print does the same, but I'm not sure.
--
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net
This implementation is HODEL-HASH-9600 compliant
