LISTSERV mailing list manager LISTSERV 16.5

Help for CODE4LIB Archives


CODE4LIB Archives

CODE4LIB Archives


CODE4LIB@LISTS.CLIR.ORG


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

CODE4LIB Home

CODE4LIB Home

CODE4LIB  November 2013

CODE4LIB November 2013

Subject:

Re: ruby-marc api design feedback wanted

From:

Jonathan Rochkind <[log in to unmask]>

Reply-To:

Code for Libraries <[log in to unmask]>

Date:

Wed, 20 Nov 2013 12:08:33 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (138 lines)

Yeah, the default in ruby-marc for encodings that _aren't_ MARC8 are to 
ignore bad bytes entirely -- leave them in the MARC::Record as bad 
bytes. This is likely end up raising an exception later when you try to 
DO something with those Strings, but was left this way for backwards 
compatiblity reasons.

You can optionally tell ruby-marc to raise or 'fix' these bad bytes 
instead, but the default is to leave them alone.

However, that's not really possible for MARC8->UTF8 conversion. Since a 
conversion is going on, bad bytes can't be 'left alone', something has 
to be done with them -- raise or replace.

My question here is solely about MARC8->UTF8 conversion, I am not 
changing anything else about the ruby-marc API at this time.

"I think raising an exception is fine, as long as we can still continue
  to walk the records with the reader."  Honestly, I'm not sure if 
that's true, I'm not sure how easy it's going to be to continue 
iterating through the records after an exception, I think the exception 
gets raised in a place that leaves the reader inconsistent. If so, there 
may not be any easy way to fix that. Bah. Scott, you want to beta test 
this new version of ruby-marc?

At any rate, pull requests always welcome once it gets released, having 
some MARC8->UTF8 conversion seems an improvement even if the details 
aren't right. We've always placed a premium on backwards compat in 
ruby-marc though, so I wanted to try and avoid making api/default 
choices we'd later regret but not want to change for backwards compat.


On 11/20/13 11:40 AM, Scott Prater wrote:
> Not sure what the details of our issue was on Monday -- but we do have
> records that are supposedly encoded in UTF-8, but nonetheless contain
> invalid characters.
>
> I think raising an exception is fine, as long as we can still continue
> to walk the records with the reader.  The right thing for application
> code to do then would be to catch the exception, log it, and continue to
> the next record.  The more information in the exception, the better.
>
> -- Scott
>
>> I am not sure how you ran into this problem on Monday with ruby-marc,
>> since ruby-marc doesn't currently handle Marc8 conversion to UTF-8 at
>> all -- how could you have run into a problem with Marc8 to UTF8
>> conversion?  But that is what I am adding.
>>
>> But yeah, using a preprocessor is certainly one option, that will not be
>> taken away from people. Although hopefully adding Marc8->UTF8 conversion
>> to ruby-marc might remove the need for a preprocessor in many cases.
>>
>> So again, we have a bit of a paradox, that I have in my own head too.
>> Scot suggests that "In either case, what we DON'T want is to halt the
>> processing altogether."  And yet, still, that the default behavior
>> should be raising an exception -- that, is halting processing
>> altogether, right?
>>
>> So hardly anyone hardly ever is going to want the default behavior, but
>> everyone thinks it should be default anyway, to force people to realize
>> what they're doing? I am not entirely objecting to that -- it's why I
>> brought it up here, but it does seem odd, doesn't it?  To say something
>> should be default that hardly anyone hardly ever will want?
>>
>>
>> On 11/20/13 10:10 AM, Scott Prater wrote:
>>> We run into this problem fairly regularly, and in fact, ran into it on
>>> Monday with ruby-marc.
>>>
>>> The way we've traditionally handled it is to put our marc stream through
>>> a cleanup preprocessor before passing it off to a marc parser (ruby marc
>>> or marc4j).
>>>
>>> The preprocessor can do one of two things:
>>>
>>>    1)  Skip the bad record in the marc stream and move on; or
>>>    2)  Substitute the bad characters with some default character, and
>>> write it out.
>>>
>>> In both cases we log the error as a warning, and include a byte offset
>>> where the bad character occurs, and the record ID, if possible.  This
>>> allows us to go back and fix the errors in a stream in a batch;
>>> generally, the bad encoding errors fall into four or five common errors
>>> (cutting and pasting data from Windows is a typical cause).
>>>
>>> In either case, what we DON'T want is to halt the processing altogether.
>>>   Generally, we're dealing with thousands, sometimes millions, of MARC
>>> records in a stream;  it's very frustrating to get halfway through the
>>> stream, then have the parser throw an exception and halt.  Halting the
>>> processing should be the strategy of last resort, to be called only when
>>> the stream has become so corrupted you can't go on to the next record.
>>>
>>> I'd want the default to be option 1.  Let the user determine what
>>> changes need to be made to the data;  the parser's job is to parse, not
>>> infer and create.  Overwriting data could also lead to the misperception
>>> that everything is okay, when it really isn't.
>>>
>>> -- Scott
>>>
>>> On 11/20/2013 08:32 AM, Jon Stroop wrote:
>>>> Coming from nowhere on this...is there a place where it would be
>>>> convenient to flag which behavior the user (of the library) wants? I
>>>> think you're correct that most of the time you'd just want to blow
>>>> through it (or replace it), but for the situation where this isn't the
>>>> case, I think the Right Thing to do is raise the exception. I don't
>>>> think you would want to bury it in some assumption made internal to the
>>>> library unless that assumption can be turned off.
>>>>
>>>> -Jon
>>>>
>>>>
>>>> On 11/19/2013 07:51 PM, Jonathan Rochkind wrote:
>>>>> ruby-marc users, a question.
>>>>>
>>>>> I am working on some Marc8 to UTF-8 conversion for ruby-marc.
>>>>>
>>>>> Sometimes, what appears to be an illegal byte will appear in the Marc8
>>>>> input, and it can not be converted to UTF8.
>>>>>
>>>>> The software will support two alternatives when this happens: 1)
>>>>> Raising an exception. 2) Replacing the illegal byte with a replacement
>>>>> char and/or omitting it.
>>>>>
>>>>> I feel like most of the time, users are going to want #2.  I know
>>>>> that's what I'm going to want nearly all the time.
>>>>>
>>>>> Yet, still, I am feeling uncertain whether that should be the default.
>>>>> Which should be the default behavior, #1 or #2?  If most people most
>>>>> of the time are going to want #2 (is this true?), then should that be
>>>>> the default behavior?   Or should #1 still be the default behavior,
>>>>> because by default bad input should raise, not be silently recovered
>>>>> from, even though most people most of the time won't want that, heh.
>>>>>
>>>>> Jonathan
>>>
>>>
>
>

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

March 2021
February 2021
January 2021
December 2020
November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003

ATOM RSS1 RSS2



LISTS.CLIR.ORG

CataList Email List Search Powered by the LISTSERV Email List Manager