[ruby-core:41340] [ruby-trunk - Feature #5678][Open] StringIO#to_str

[ruby-core:41340] [ruby-trunk - Feature #5678][Open] StringIO#to_str

[Martin Bosslet]

Issue #5678 has been reported by Martin Bosslet.

----------------------------------------
Feature #5678: StringIO#to_str
http://redmine.ruby-lang.org/issues/5678

Author: Martin Bosslet
Status: Open
Priority: Normal
Assignee: Nobuyoshi Nakada
Category: ext
Target version: 2.0.0


The following raises an error currently:

  require 'stringio'
  require 'openssl'

  io = StringIO.new(OpenSSL::ASN1::Integer.new(1).to_der)
  asn = OpenSSL::ASN1.decode io

The reason is that ossl_obj2bio[1] looks for a
T_FILE first, and then it tries to coerce the
input to a String using StringValue. StringValue
itself again expects the presence of to_str,
which is currently missing for StringIO, but
could be easily provided by aliasing 
StringIO#string. 

I could imagine that the heuristic of ossl_obj2bio
is quite common when working on binary data in a
C extension. Would it therefore be OK to add 
StringIO#to_str? Patch attached.


[1] https://github.com/ruby/ruby/blob/trunk/ext/openssl/ossl_bio.c#L17


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[ruby-core:41345] [ruby-trunk - Feature #5678][Feedback] StringIO#to_str

[Nobuyoshi Nakada]

Issue #5678 has been updated by Nobuyoshi Nakada.

Status changed from Open to Feedback

Martin Bosslet wrote:
> The following raises an error currently:
> 
>   require 'stringio'
>   require 'openssl'
> 
>   io = StringIO.new(OpenSSL::ASN1::Integer.new(1).to_der)
>   asn = OpenSSL::ASN1.decode io

Why do you need to pass `io', not io.string or the result of to_der?

----------------------------------------
Feature #5678: StringIO#to_str
http://redmine.ruby-lang.org/issues/5678

Author: Martin Bosslet
Status: Feedback
Priority: Normal
Assignee: Nobuyoshi Nakada
Category: ext
Target version: 2.0.0


The following raises an error currently:

  require 'stringio'
  require 'openssl'

  io = StringIO.new(OpenSSL::ASN1::Integer.new(1).to_der)
  asn = OpenSSL::ASN1.decode io

The reason is that ossl_obj2bio[1] looks for a
T_FILE first, and then it tries to coerce the
input to a String using StringValue. StringValue
itself again expects the presence of to_str,
which is currently missing for StringIO, but
could be easily provided by aliasing 
StringIO#string. 

I could imagine that the heuristic of ossl_obj2bio
is quite common when working on binary data in a
C extension. Would it therefore be OK to add 
StringIO#to_str? Patch attached.


[1] https://github.com/ruby/ruby/blob/trunk/ext/openssl/ossl_bio.c#L17


-- 
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[ruby-core:41347] [ruby-trunk - Feature #5678] StringIO#to_str

[Martin Bosslet]

Issue #5678 has been updated by Martin Bosslet.


Nobuyoshi Nakada wrote:
> Martin Bosslet wrote:
> > The following raises an error currently:
> > 
> >   require 'stringio'
> >   require 'openssl'
> > 
> >   io = StringIO.new(OpenSSL::ASN1::Integer.new(1).to_der)
> >   asn = OpenSSL::ASN1.decode io
> 
> Why do you need to pass `io', not io.string or the result of to_der?

I don't really need to, it's just that I am working on making 
ASN1.decode streaming-aware. So I wanted it to work with any 
IO or IO-like object and additionally with Strings. That's why 
I thought if someone passes a StringIO, they would be surprised
if an error was raised - they passed an IO-like object after all
and there is no apparent reason why this shouldn't work.

I could, however, call StringIO#string as you suggested, but
I would prefer to use StringValue, as a more generic way
of coercing things into Strings. And it would potentially work
for a wider variety of objects, not only limited to StringIO. 

Do you see any negative aspects when adding StringIO#to_str? 
----------------------------------------
Feature #5678: StringIO#to_str
http://redmine.ruby-lang.org/issues/5678

Author: Martin Bosslet
Status: Feedback
Priority: Normal
Assignee: Nobuyoshi Nakada
Category: ext
Target version: 2.0.0


The following raises an error currently:

  require 'stringio'
  require 'openssl'

  io = StringIO.new(OpenSSL::ASN1::Integer.new(1).to_der)
  asn = OpenSSL::ASN1.decode io

The reason is that ossl_obj2bio[1] looks for a
T_FILE first, and then it tries to coerce the
input to a String using StringValue. StringValue
itself again expects the presence of to_str,
which is currently missing for StringIO, but
could be easily provided by aliasing 
StringIO#string. 

I could imagine that the heuristic of ossl_obj2bio
is quite common when working on binary data in a
C extension. Would it therefore be OK to add 
StringIO#to_str? Patch attached.


[1] https://github.com/ruby/ruby/blob/trunk/ext/openssl/ossl_bio.c#L17


-- 
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[ruby-core:41352] Re: [ruby-trunk - Feature #5678] StringIO#to_str

[Yukihiro Matsumoto]

Hi,

In message "Re: [ruby-core:41347] [ruby-trunk - Feature #5678] StringIO#to_str"
    on Mon, 28 Nov 2011 11:16:33 +0900, Martin Bosslet <Martin.Bosslet@googlemail.com> writes:

|Do you see any negative aspects when adding StringIO#to_str? 

Yes, to_str should be implemented for objects that have (almost) same
method signature as strings, which is not true for StringIO.

							matz.

[ruby-core:41354] [ruby-trunk - Feature #5678][Closed] StringIO#to_str

[Martin Bosslet]

Issue #5678 has been updated by Martin Bosslet.

Status changed from Feedback to Closed

Yukihiro Matsumoto wrote:
> Hi,
>  
>  In message "Re: [ruby-core:41347] [ruby-trunk - Feature #5678] StringIO#to_str"
>      on Mon, 28 Nov 2011 11:16:33 +0900, Martin Bosslet <Martin.Bosslet@googlemail.com> writes:
>  
>  |Do you see any negative aspects when adding StringIO#to_str? 
>  
>  Yes, to_str should be implemented for objects that have (almost) same
>  method signature as strings, which is not true for StringIO.
>  
>  							matz.

OK, thank you for clarifying this! I will use StringIO#string then.

----------------------------------------
Feature #5678: StringIO#to_str
http://redmine.ruby-lang.org/issues/5678

Author: Martin Bosslet
Status: Closed
Priority: Normal
Assignee: Nobuyoshi Nakada
Category: ext
Target version: 2.0.0


The following raises an error currently:

  require 'stringio'
  require 'openssl'

  io = StringIO.new(OpenSSL::ASN1::Integer.new(1).to_der)
  asn = OpenSSL::ASN1.decode io

The reason is that ossl_obj2bio[1] looks for a
T_FILE first, and then it tries to coerce the
input to a String using StringValue. StringValue
itself again expects the presence of to_str,
which is currently missing for StringIO, but
could be easily provided by aliasing 
StringIO#string. 

I could imagine that the heuristic of ossl_obj2bio
is quite common when working on binary data in a
C extension. Would it therefore be OK to add 
StringIO#to_str? Patch attached.


[1] https://github.com/ruby/ruby/blob/trunk/ext/openssl/ossl_bio.c#L17


-- 
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[ruby-core:41355] Re: [ruby-trunk - Feature #5678] StringIO#to_str

[Nikolai Weibull]

On Mon, Nov 28, 2011 at 07:16, Yukihiro Matsumoto <matz@ruby-lang.org> wrote:

> In message "Re: [ruby-core:41347] [ruby-trunk - Feature #5678] StringIO#to_str"
>    on Mon, 28 Nov 2011 11:16:33 +0900, Martin Bosslet <Martin.Bosslet@googlemail.com> writes:
>
> |Do you see any negative aspects when adding StringIO#to_str?

> Yes, to_str should be implemented for objects that have (almost) same
> method signature as strings, which is not true for StringIO.

How about implementing #to_s instead?

[ruby-core:41356] Re: [ruby-trunk - Feature #5678][Closed] StringIO#to_str

[Yukihiro Matsumoto]

Hi,
In message "Re: [ruby-core:41354] [ruby-trunk - Feature #5678][Closed] StringIO#to_str"
    on Mon, 28 Nov 2011 18:50:12 +0900, Martin Bosslet <Martin.Bosslet@googlemail.com> writes:

|OK, thank you for clarifying this! I will use StringIO#string then.

At the same time, having ASN1.decode to treat T_FILE but not StringIO
is against duck typing.  I think it is better if we can do something.
But I don't have a good idea yet.  #to_io does not work here. #to_str
is not appropriate.

							matz.

[ruby-core:41378] [ruby-trunk - Feature #5678] StringIO#to_str

[Martin Bosslet]

Issue #5678 has been updated by Martin Bosslet.


Yukihiro Matsumoto wrote:
> Hi,
>  In message "Re: [ruby-core:41354] [ruby-trunk - Feature #5678][Closed] StringIO#to_str"
>      on Mon, 28 Nov 2011 18:50:12 +0900, Martin Bosslet <Martin.Bosslet@googlemail.com> writes:
>  
>  At the same time, having ASN1.decode to treat T_FILE but not StringIO
>  is against duck typing.  I think it is better if we can do something.
>  But I don't have a good idea yet.  #to_io does not work here. #to_str
>  is not appropriate.
>  
>  							matz.

We could handle StringIO exceptionally by trying to call #string on the
object passed. But that's not too elegant and will probably only work in
the very specific case of StringIO. Implementing #to_s like Nikolai
suggested could be another solution? Then we could apply the following 
heuristic that should cover almost any (valid) case:

1. check for T_FILE
2. try #to_str
3. try #to_s ?

----------------------------------------
Feature #5678: StringIO#to_str
http://redmine.ruby-lang.org/issues/5678

Author: Martin Bosslet
Status: Closed
Priority: Normal
Assignee: Nobuyoshi Nakada
Category: ext
Target version: 2.0.0


The following raises an error currently:

  require 'stringio'
  require 'openssl'

  io = StringIO.new(OpenSSL::ASN1::Integer.new(1).to_der)
  asn = OpenSSL::ASN1.decode io

The reason is that ossl_obj2bio[1] looks for a
T_FILE first, and then it tries to coerce the
input to a String using StringValue. StringValue
itself again expects the presence of to_str,
which is currently missing for StringIO, but
could be easily provided by aliasing 
StringIO#string. 

I could imagine that the heuristic of ossl_obj2bio
is quite common when working on binary data in a
C extension. Would it therefore be OK to add 
StringIO#to_str? Patch attached.


[1] https://github.com/ruby/ruby/blob/trunk/ext/openssl/ossl_bio.c#L17


-- 
http://redmine.ruby-lang.org