Re: Not-yet-broken breaking changes for Tika 2?

2018-02-07 Thread Chris Mattmann 
IMO, if the parser p1 has an exception and then we move to p2 before p1 is done 
creating its SAX we can create a special tag indicating the exception e.g., 
Message here and have it output that before moving to p2 in the chain...



On 2/7/18, 7:00 AM, "Allison, Timothy B."  wrote:

Do we worry about properly closing tags on an exception?




kaboom
mailto:lfcnas...@gmail.com] 
Sent: Monday, February 5, 2018 5:34 PM
To: dev@tika.apache.org
    Subject: Re: Not-yet-broken breaking changes for Tika 2?

From a forensic use case it is better just saying we are trying another 
parser and not resetting the content handler, because the first parser can 
extract relevant content before the exception.

To not spool everything to temp files to re-read the stream, I think we can 
create an optional setinputstreamfactory() method in TikaInputStream, so the 
user can implement an InputStreamFactory interface with a getInputStream 
method, if he does not want to pay a performance hit with temp files for 
everything.

Luis

Em 5 de fev de 2018 4:52 PM, "Chris Mattmann" 
escreveu:

I think we should just say, OK now we're trying  a different parser



On 2/5/18, 9:51 AM, "Allison, Timothy B."  wrote:

To my mind, the real challenge is what to do with content that should 
be ignored...

If the strategy is back-off-on-exception (try the DOCX parser, but if 
there's an exception, use the Zip parser), what do we do with the sax elements 
that have already been written?  Do we need a new handler type that has a 
reset() method?

Or do we just say, hey, now we're trying a different parser...


-Original Message-
From: Mattmann, Chris A (1761) [mailto:chris.a.mattm...@jpl.nasa.gov]
Sent: Monday, February 5, 2018 12:29 PM
    To: dev@tika.apache.org
    Subject: Re: Not-yet-broken breaking changes for Tika 2?

Our solution is just to run the parser 2xyes I get it will induce 
overhead, but as a start, why not?
In short just run through the stream 2x


++
Chris Mattmann, Ph.D.
Associate Chief Technology and Innovation Officer, OCIO Manager, 
Advanced IT Research and Open Source Projects Office (1761) Manager, NSF and 
Open Source Programs and Applications Office (8212) NASA Jet Propulsion 
Laboratory Pasadena, CA 91109 USA
Office: 180-503E, Mailstop: 180-502
Email: chris.a.mattm...@nasa.gov
WWW:  http://sunset.usc.edu/~mattmann/

++
Director, Information Retrieval and Data Science Group (IRDS) Adjunct 
Associate Professor, Computer Science Department University of Southern 
California, Los Angeles, CA 90089 USA
WWW: http://irds.usc.edu/

++


On 2/5/18, 9:25 AM, "Nick Burch"  wrote:

On Mon, 5 Feb 2018, Chris Mattmann wrote:
> Let's have a go at implementing it! You know my thoughts (make it 
like
> OODT ;) )\

I'm still keen to hear how we can do the text content like OODT!

I have tried to copy the OODT model for the proposed metadata case 
though
:)

Nick

> On 2/5/18, 8:37 AM, "Nick Burch"  wrote:
>
>Ping - anyone got any thoughts on the proposed metadata parser
stuff, and
>any ideas on the content part?
>
>On Tue, 2 Jan 2018, Nick Burch wrote:
>> On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>> On collision, the precedence order defines what key takes
precedence and
>>> _overwrites_ the other. Overwrite is but one option (you
could save *all*
>>> the values it’s a multi-valued key structure so…)
>>
>> OK, I think that's fine. I've had a go at updating the wiki
for the metadata
>> case:
>> https://wiki.apache.org/tika/CompositeParserDiscussion#
Supplementary.2FAdditive
>> And example Tika Config settings for it
>> https://wiki.apache.org/tika/CompositeParserDiscussion#
line-20
>> If people are happy with how that sounds/looks, I can have a
stab at
>> implementing it, as I *think* it's quite easy
>>
>>
>> However... that

Re: Not-yet-broken breaking changes for Tika 2?

2018-02-07 Thread Luís Filipe Nassif 
Mine too, but I know it is important for many use cases. Maybe adding to
XHtmlContentHandler some tracking of open tags and a new method to close
them?

2018-02-07 12:59 GMT-02:00 Allison, Timothy B. :

> Do we worry about properly closing tags on an exception?
>
> 
> 
> 
> kaboom
> mailto:lfcnas...@gmail.com]
> Sent: Monday, February 5, 2018 5:34 PM
> To: dev@tika.apache.org
> Subject: Re: Not-yet-broken breaking changes for Tika 2?
>
> From a forensic use case it is better just saying we are trying another
> parser and not resetting the content handler, because the first parser can
> extract relevant content before the exception.
>
> To not spool everything to temp files to re-read the stream, I think we
> can create an optional setinputstreamfactory() method in TikaInputStream,
> so the user can implement an InputStreamFactory interface with a
> getInputStream method, if he does not want to pay a performance hit with
> temp files for everything.
>
> Luis
>
> Em 5 de fev de 2018 4:52 PM, "Chris Mattmann" 
> escreveu:
>
> I think we should just say, OK now we're trying  a different parser
>
>
>
> On 2/5/18, 9:51 AM, "Allison, Timothy B."  wrote:
>
> To my mind, the real challenge is what to do with content that should
> be ignored...
>
> If the strategy is back-off-on-exception (try the DOCX parser, but if
> there's an exception, use the Zip parser), what do we do with the sax
> elements that have already been written?  Do we need a new handler type
> that has a reset() method?
>
> Or do we just say, hey, now we're trying a different parser...
>
>
> -Original Message-
>     From: Mattmann, Chris A (1761) [mailto:chris.a.mattm...@jpl.nasa.gov]
> Sent: Monday, February 5, 2018 12:29 PM
> To: dev@tika.apache.org
> Subject: Re: Not-yet-broken breaking changes for Tika 2?
>
> Our solution is just to run the parser 2xyes I get it will induce
> overhead, but as a start, why not?
> In short just run through the stream 2x
>
> 
> ++
> Chris Mattmann, Ph.D.
> Associate Chief Technology and Innovation Officer, OCIO Manager,
> Advanced IT Research and Open Source Projects Office (1761) Manager, NSF
> and Open Source Programs and Applications Office (8212) NASA Jet Propulsion
> Laboratory Pasadena, CA 91109 USA
> Office: 180-503E, Mailstop: 180-502
> Email: chris.a.mattm...@nasa.gov
> WWW:  http://sunset.usc.edu/~mattmann/
> 
> ++
> Director, Information Retrieval and Data Science Group (IRDS) Adjunct
> Associate Professor, Computer Science Department University of Southern
> California, Los Angeles, CA 90089 USA
> WWW: http://irds.usc.edu/
> 
> ++
>
>
> On 2/5/18, 9:25 AM, "Nick Burch"  wrote:
>
> On Mon, 5 Feb 2018, Chris Mattmann wrote:
> > Let's have a go at implementing it! You know my thoughts (make
> it like
> > OODT ;) )\
>
> I'm still keen to hear how we can do the text content like OODT!
>
> I have tried to copy the OODT model for the proposed metadata case
> though
> :)
>
> Nick
>
> > On 2/5/18, 8:37 AM, "Nick Burch"  wrote:
> >
> >Ping - anyone got any thoughts on the proposed metadata parser
> stuff, and
> >any ideas on the content part?
> >
> >On Tue, 2 Jan 2018, Nick Burch wrote:
> >> On Thu, 26 Oct 2017, Chris Mattmann wrote:
> >>> On collision, the precedence order defines what key takes
> precedence and
> >>> _overwrites_ the other. Overwrite is but one option (you
> could save *all*
> >>> the values it’s a multi-valued key structure so…)
> >>
> >> OK, I think that's fine. I've had a go at updating the wiki
> for the metadata
> >> case:
> >> https://wiki.apache.org/tika/CompositeParserDiscussion#
> Supplementary.2FAdditive
> >> And example Tika Config settings for it
> >> https://wiki.apache.org/tika/CompositeParserDiscussion#
> line-20
> >> If people are happy with how that sounds/looks, I can have a
> stab at
> >> implementing it, as I *think* it's quite easy
> >>

RE: Not-yet-broken breaking changes for Tika 2?

2018-02-07 Thread Allison, Timothy B. 
Do we worry about properly closing tags on an exception?




kaboom
mailto:lfcnas...@gmail.com] 
Sent: Monday, February 5, 2018 5:34 PM
To: dev@tika.apache.org
Subject: Re: Not-yet-broken breaking changes for Tika 2?

From a forensic use case it is better just saying we are trying another parser 
and not resetting the content handler, because the first parser can extract 
relevant content before the exception.

To not spool everything to temp files to re-read the stream, I think we can 
create an optional setinputstreamfactory() method in TikaInputStream, so the 
user can implement an InputStreamFactory interface with a getInputStream 
method, if he does not want to pay a performance hit with temp files for 
everything.

Luis

Em 5 de fev de 2018 4:52 PM, "Chris Mattmann" 
escreveu:

I think we should just say, OK now we're trying  a different parser



On 2/5/18, 9:51 AM, "Allison, Timothy B."  wrote:

To my mind, the real challenge is what to do with content that should be 
ignored...

If the strategy is back-off-on-exception (try the DOCX parser, but if 
there's an exception, use the Zip parser), what do we do with the sax elements 
that have already been written?  Do we need a new handler type that has a 
reset() method?

Or do we just say, hey, now we're trying a different parser...


-Original Message-
From: Mattmann, Chris A (1761) [mailto:chris.a.mattm...@jpl.nasa.gov]
Sent: Monday, February 5, 2018 12:29 PM
To: dev@tika.apache.org
Subject: Re: Not-yet-broken breaking changes for Tika 2?

Our solution is just to run the parser 2xyes I get it will induce 
overhead, but as a start, why not?
In short just run through the stream 2x


++
Chris Mattmann, Ph.D.
Associate Chief Technology and Innovation Officer, OCIO Manager, Advanced 
IT Research and Open Source Projects Office (1761) Manager, NSF and Open Source 
Programs and Applications Office (8212) NASA Jet Propulsion Laboratory 
Pasadena, CA 91109 USA
Office: 180-503E, Mailstop: 180-502
Email: chris.a.mattm...@nasa.gov
WWW:  http://sunset.usc.edu/~mattmann/

++
Director, Information Retrieval and Data Science Group (IRDS) Adjunct 
Associate Professor, Computer Science Department University of Southern 
California, Los Angeles, CA 90089 USA
WWW: http://irds.usc.edu/

++


On 2/5/18, 9:25 AM, "Nick Burch"  wrote:

On Mon, 5 Feb 2018, Chris Mattmann wrote:
> Let's have a go at implementing it! You know my thoughts (make it like
> OODT ;) )\

I'm still keen to hear how we can do the text content like OODT!

I have tried to copy the OODT model for the proposed metadata case 
though
:)

Nick

> On 2/5/18, 8:37 AM, "Nick Burch"  wrote:
>
>Ping - anyone got any thoughts on the proposed metadata parser
stuff, and
>any ideas on the content part?
>
>On Tue, 2 Jan 2018, Nick Burch wrote:
>> On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>> On collision, the precedence order defines what key takes
precedence and
>>> _overwrites_ the other. Overwrite is but one option (you
could save *all*
>>> the values it’s a multi-valued key structure so…)
>>
>> OK, I think that's fine. I've had a go at updating the wiki
for the metadata
>> case:
>> https://wiki.apache.org/tika/CompositeParserDiscussion#
Supplementary.2FAdditive
>> And example Tika Config settings for it
>> https://wiki.apache.org/tika/CompositeParserDiscussion#
line-20
>> If people are happy with how that sounds/looks, I can have a
stab at
>> implementing it, as I *think* it's quite easy
>>
>>
>> However... that still leaves the Context (XHTML SAX events)
case to solve!
>>
>> Anyone have any ideas on how we can append to or
cancel/reset the Content
>> Handler series of SAX events when we move onto a second+
parser for a file?
>>
>> Thanks
>> Nick
>>
>>> On 10/26/17, 9:43 AM, "Nick Burch" 
wrote:
>>>
>>>On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>>> My general approach to conflicting metadata is simply
to define
>>>> pre

Re: Not-yet-broken breaking changes for Tika 2?

2018-02-05 Thread Luís Filipe Nassif 
>From a forensic use case it is better just saying we are trying another
parser and not resetting the content handler, because the first parser can
extract relevant content before the exception.

To not spool everything to temp files to re-read the stream, I think we can
create an optional setinputstreamfactory() method in TikaInputStream, so
the user can implement an InputStreamFactory interface with a
getInputStream method, if he does not want to pay a performance hit with
temp files for everything.

Luis

Em 5 de fev de 2018 4:52 PM, "Chris Mattmann" 
escreveu:

I think we should just say, OK now we're trying  a different parser



On 2/5/18, 9:51 AM, "Allison, Timothy B."  wrote:

To my mind, the real challenge is what to do with content that should
be ignored...

If the strategy is back-off-on-exception (try the DOCX parser, but if
there's an exception, use the Zip parser), what do we do with the sax
elements that have already been written?  Do we need a new handler type
that has a reset() method?

Or do we just say, hey, now we're trying a different parser...


-Original Message-
From: Mattmann, Chris A (1761) [mailto:chris.a.mattm...@jpl.nasa.gov]
Sent: Monday, February 5, 2018 12:29 PM
    To: dev@tika.apache.org
    Subject: Re: Not-yet-broken breaking changes for Tika 2?

Our solution is just to run the parser 2xyes I get it will induce
overhead, but as a start, why not?
In short just run through the stream 2x


++
Chris Mattmann, Ph.D.
Associate Chief Technology and Innovation Officer, OCIO Manager,
Advanced IT Research and Open Source Projects Office (1761) Manager, NSF
and Open Source Programs and Applications Office (8212) NASA Jet Propulsion
Laboratory Pasadena, CA 91109 USA
Office: 180-503E, Mailstop: 180-502
Email: chris.a.mattm...@nasa.gov
WWW:  http://sunset.usc.edu/~mattmann/

++
Director, Information Retrieval and Data Science Group (IRDS) Adjunct
Associate Professor, Computer Science Department University of Southern
California, Los Angeles, CA 90089 USA
WWW: http://irds.usc.edu/

++


On 2/5/18, 9:25 AM, "Nick Burch"  wrote:

On Mon, 5 Feb 2018, Chris Mattmann wrote:
> Let's have a go at implementing it! You know my thoughts (make it
like
> OODT ;) )\

I'm still keen to hear how we can do the text content like OODT!

I have tried to copy the OODT model for the proposed metadata case
though
:)

Nick

> On 2/5/18, 8:37 AM, "Nick Burch"  wrote:
>
>Ping - anyone got any thoughts on the proposed metadata parser
stuff, and
>any ideas on the content part?
>
>On Tue, 2 Jan 2018, Nick Burch wrote:
>> On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>> On collision, the precedence order defines what key takes
precedence and
>>> _overwrites_ the other. Overwrite is but one option (you
could save *all*
>>> the values it’s a multi-valued key structure so…)
>>
>> OK, I think that's fine. I've had a go at updating the wiki
for the metadata
>> case:
>> https://wiki.apache.org/tika/CompositeParserDiscussion#
Supplementary.2FAdditive
>> And example Tika Config settings for it
>> https://wiki.apache.org/tika/CompositeParserDiscussion#
line-20
>> If people are happy with how that sounds/looks, I can have a
stab at
>> implementing it, as I *think* it's quite easy
>>
>>
>> However... that still leaves the Context (XHTML SAX events)
case to solve!
>>
>> Anyone have any ideas on how we can append to or
cancel/reset the Content
>> Handler series of SAX events when we move onto a second+
parser for a file?
>>
>> Thanks
>> Nick
>>
>>> On 10/26/17, 9:43 AM, "Nick Burch" 
wrote:
>>>
>>>On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>>> My general approach to conflicting metadata is simply
to define
>>>> precedence orders.
>>>>
>>>> For example here is one documented from OODT:
>>>>
>>>>
>>> https://cwiki.apache.org/confluence/disp

Re: Not-yet-broken breaking changes for Tika 2?

2018-02-05 Thread Chris Mattmann 
I think we should just say, OK now we're trying  a different parser



On 2/5/18, 9:51 AM, "Allison, Timothy B."  wrote:

To my mind, the real challenge is what to do with content that should be 
ignored...

If the strategy is back-off-on-exception (try the DOCX parser, but if 
there's an exception, use the Zip parser), what do we do with the sax elements 
that have already been written?  Do we need a new handler type that has a 
reset() method?

Or do we just say, hey, now we're trying a different parser...


-Original Message-
From: Mattmann, Chris A (1761) [mailto:chris.a.mattm...@jpl.nasa.gov] 
Sent: Monday, February 5, 2018 12:29 PM
To: dev@tika.apache.org
Subject: Re: Not-yet-broken breaking changes for Tika 2?

Our solution is just to run the parser 2xyes I get it will induce 
overhead, but as a start, why not?
In short just run through the stream 2x

++
Chris Mattmann, Ph.D.
Associate Chief Technology and Innovation Officer, OCIO Manager, Advanced 
IT Research and Open Source Projects Office (1761) Manager, NSF and Open Source 
Programs and Applications Office (8212) NASA Jet Propulsion Laboratory 
Pasadena, CA 91109 USA
Office: 180-503E, Mailstop: 180-502
Email: chris.a.mattm...@nasa.gov
WWW:  http://sunset.usc.edu/~mattmann/
++
Director, Information Retrieval and Data Science Group (IRDS) Adjunct 
Associate Professor, Computer Science Department University of Southern 
California, Los Angeles, CA 90089 USA
WWW: http://irds.usc.edu/
++
 
 
On 2/5/18, 9:25 AM, "Nick Burch"  wrote:

On Mon, 5 Feb 2018, Chris Mattmann wrote:
> Let's have a go at implementing it! You know my thoughts (make it 
like 
> OODT ;) )\

I'm still keen to hear how we can do the text content like OODT!

I have tried to copy the OODT model for the proposed metadata case 
though 
:)

Nick

> On 2/5/18, 8:37 AM, "Nick Burch"  wrote:
>
>Ping - anyone got any thoughts on the proposed metadata parser 
stuff, and
>any ideas on the content part?
>
>On Tue, 2 Jan 2018, Nick Burch wrote:
>> On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>> On collision, the precedence order defines what key takes 
precedence and
>>> _overwrites_ the other. Overwrite is but one option (you could 
save *all*
>>> the values it’s a multi-valued key structure so…)
>>
>> OK, I think that's fine. I've had a go at updating the wiki for 
the metadata
>> case:
>> 
https://wiki.apache.org/tika/CompositeParserDiscussion#Supplementary.2FAdditive
>> And example Tika Config settings for it
>> https://wiki.apache.org/tika/CompositeParserDiscussion#line-20
>> If people are happy with how that sounds/looks, I can have a 
stab at
>> implementing it, as I *think* it's quite easy
>>
>>
>> However... that still leaves the Context (XHTML SAX events) case 
to solve!
>>
>> Anyone have any ideas on how we can append to or cancel/reset 
the Content
>> Handler series of SAX events when we move onto a second+ parser 
for a file?
>>
>> Thanks
>> Nick
>>
>>> On 10/26/17, 9:43 AM, "Nick Burch"  wrote:
>>>
>>>On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>>> My general approach to conflicting metadata is simply to 
define
>>>> precedence orders.
>>>>
>>>> For example here is one documented from OODT:
>>>>
>>>>
>>> 
https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence
>>>>
>>>> We can do similar things with Tika, e.g.,
>>>>
>>>> [CoreMetadata.PROPERTIES]
>>>> [ImageParser.METADATA]
>>>> [TikaOCR.METADATA]
>>>
>>>What happens if two different parsers both output the same 
bit of
>>> metadata
>>>though? eg Tim's example of one giving dc:creator of Tim and 
the second
>>>giving dc:creator of Chris?
>>>
>>>
>>>Secondly, what about the XHTML sax events stream? I think 
that's
>>> probably
>>>the harder case...
>>>
>>>Nick
>
>
>

RE: Not-yet-broken breaking changes for Tika 2?

2018-02-05 Thread Allison, Timothy B. 
On the metadata stuff, I'm coming around to Ray Gauss's proposal.  I wanted too 
much back then, and his solution is super elegant, IIRC.

-Original Message-
From: Nick Burch [mailto:apa...@gagravarr.org] 
Sent: Monday, February 5, 2018 11:37 AM
To: dev@tika.apache.org
Subject: Re: Not-yet-broken breaking changes for Tika 2?

Ping - anyone got any thoughts on the proposed metadata parser stuff, and any 
ideas on the content part?

On Tue, 2 Jan 2018, Nick Burch wrote:
> On Thu, 26 Oct 2017, Chris Mattmann wrote:
>> On collision, the precedence order defines what key takes precedence 
>> and _overwrites_ the other. Overwrite is but one option (you could 
>> save *all* the values it’s a multi-valued key structure so…)
>
> OK, I think that's fine. I've had a go at updating the wiki for the 
> metadata
> case:
> https://wiki.apache.org/tika/CompositeParserDiscussion#Supplementary.2
> FAdditive And example Tika Config settings for it
> https://wiki.apache.org/tika/CompositeParserDiscussion#line-20
> If people are happy with how that sounds/looks, I can have a stab at 
> implementing it, as I *think* it's quite easy
>
>
> However... that still leaves the Context (XHTML SAX events) case to solve!
>
> Anyone have any ideas on how we can append to or cancel/reset the 
> Content Handler series of SAX events when we move onto a second+ parser for a 
> file?
>
> Thanks
> Nick
>
>> On 10/26/17, 9:43 AM, "Nick Burch"  wrote:
>>
>>On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>> My general approach to conflicting metadata is simply to define
>>> precedence orders.
>>>
>>> For example here is one documented from OODT:
>>>
>>>
>> https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence
>>>
>>> We can do similar things with Tika, e.g.,
>>>
>>> [CoreMetadata.PROPERTIES]
>>> [ImageParser.METADATA]
>>> [TikaOCR.METADATA]
>>
>>What happens if two different parsers both output the same bit of 
>> metadata
>>though? eg Tim's example of one giving dc:creator of Tim and the second
>>giving dc:creator of Chris?
>> 
>>
>>Secondly, what about the XHTML sax events stream? I think that's 
>> probably
>>the harder case...
>>
>>Nick

RE: Not-yet-broken breaking changes for Tika 2?

2018-02-05 Thread Allison, Timothy B. 
To my mind, the real challenge is what to do with content that should be 
ignored...

If the strategy is back-off-on-exception (try the DOCX parser, but if there's 
an exception, use the Zip parser), what do we do with the sax elements that 
have already been written?  Do we need a new handler type that has a reset() 
method?

Or do we just say, hey, now we're trying a different parser...


-Original Message-
From: Mattmann, Chris A (1761) [mailto:chris.a.mattm...@jpl.nasa.gov] 
Sent: Monday, February 5, 2018 12:29 PM
To: dev@tika.apache.org
Subject: Re: Not-yet-broken breaking changes for Tika 2?

Our solution is just to run the parser 2xyes I get it will induce overhead, 
but as a start, why not?
In short just run through the stream 2x

++
Chris Mattmann, Ph.D.
Associate Chief Technology and Innovation Officer, OCIO Manager, Advanced IT 
Research and Open Source Projects Office (1761) Manager, NSF and Open Source 
Programs and Applications Office (8212) NASA Jet Propulsion Laboratory 
Pasadena, CA 91109 USA
Office: 180-503E, Mailstop: 180-502
Email: chris.a.mattm...@nasa.gov
WWW:  http://sunset.usc.edu/~mattmann/
++
Director, Information Retrieval and Data Science Group (IRDS) Adjunct Associate 
Professor, Computer Science Department University of Southern California, Los 
Angeles, CA 90089 USA
WWW: http://irds.usc.edu/
++
 
 
On 2/5/18, 9:25 AM, "Nick Burch"  wrote:

On Mon, 5 Feb 2018, Chris Mattmann wrote:
> Let's have a go at implementing it! You know my thoughts (make it like 
> OODT ;) )\

I'm still keen to hear how we can do the text content like OODT!

I have tried to copy the OODT model for the proposed metadata case though 
:)

Nick

> On 2/5/18, 8:37 AM, "Nick Burch"  wrote:
>
>Ping - anyone got any thoughts on the proposed metadata parser stuff, 
and
>any ideas on the content part?
>
>On Tue, 2 Jan 2018, Nick Burch wrote:
>> On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>> On collision, the precedence order defines what key takes 
precedence and
>>> _overwrites_ the other. Overwrite is but one option (you could save 
*all*
>>> the values it’s a multi-valued key structure so…)
>>
>> OK, I think that's fine. I've had a go at updating the wiki for the 
metadata
>> case:
>> 
https://wiki.apache.org/tika/CompositeParserDiscussion#Supplementary.2FAdditive
>> And example Tika Config settings for it
>> https://wiki.apache.org/tika/CompositeParserDiscussion#line-20
>> If people are happy with how that sounds/looks, I can have a stab at
>> implementing it, as I *think* it's quite easy
>>
>>
>> However... that still leaves the Context (XHTML SAX events) case to 
solve!
>>
>> Anyone have any ideas on how we can append to or cancel/reset the 
Content
>> Handler series of SAX events when we move onto a second+ parser for 
a file?
>>
>> Thanks
>> Nick
>>
>>> On 10/26/17, 9:43 AM, "Nick Burch"  wrote:
>>>
>>>On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>>> My general approach to conflicting metadata is simply to define
>>>> precedence orders.
>>>>
>>>> For example here is one documented from OODT:
>>>>
>>>>
>>> 
https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence
>>>>
>>>> We can do similar things with Tika, e.g.,
>>>>
>>>> [CoreMetadata.PROPERTIES]
>>>> [ImageParser.METADATA]
>>>> [TikaOCR.METADATA]
>>>
>>>What happens if two different parsers both output the same bit of
>>> metadata
>>>though? eg Tim's example of one giving dc:creator of Tim and the 
second
>>>giving dc:creator of Chris?
>>>
>>>
>>>Secondly, what about the XHTML sax events stream? I think that's
>>> probably
>>>the harder case...
>>>
>>>Nick
>
>
>

RE: Not-yet-broken breaking changes for Tika 2?

2018-02-05 Thread Allison, Timothy B. 
Spool to temp file?

-Original Message-
From: Mattmann, Chris A (1761) [mailto:chris.a.mattm...@jpl.nasa.gov] 
Sent: Monday, February 5, 2018 12:29 PM
To: dev@tika.apache.org
Subject: Re: Not-yet-broken breaking changes for Tika 2?

Our solution is just to run the parser 2xyes I get it will induce overhead, 
but as a start, why not?
In short just run through the stream 2x

++
Chris Mattmann, Ph.D.
Associate Chief Technology and Innovation Officer, OCIO Manager, Advanced IT 
Research and Open Source Projects Office (1761) Manager, NSF and Open Source 
Programs and Applications Office (8212) NASA Jet Propulsion Laboratory 
Pasadena, CA 91109 USA
Office: 180-503E, Mailstop: 180-502
Email: chris.a.mattm...@nasa.gov
WWW:  http://sunset.usc.edu/~mattmann/
++
Director, Information Retrieval and Data Science Group (IRDS) Adjunct Associate 
Professor, Computer Science Department University of Southern California, Los 
Angeles, CA 90089 USA
WWW: http://irds.usc.edu/
++
 
 
On 2/5/18, 9:25 AM, "Nick Burch"  wrote:

On Mon, 5 Feb 2018, Chris Mattmann wrote:
> Let's have a go at implementing it! You know my thoughts (make it like 
> OODT ;) )\

I'm still keen to hear how we can do the text content like OODT!

I have tried to copy the OODT model for the proposed metadata case though 
:)

Nick

> On 2/5/18, 8:37 AM, "Nick Burch"  wrote:
>
>Ping - anyone got any thoughts on the proposed metadata parser stuff, 
and
>any ideas on the content part?
>
>On Tue, 2 Jan 2018, Nick Burch wrote:
>> On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>> On collision, the precedence order defines what key takes 
precedence and
>>> _overwrites_ the other. Overwrite is but one option (you could save 
*all*
>>> the values it’s a multi-valued key structure so…)
>>
>> OK, I think that's fine. I've had a go at updating the wiki for the 
metadata
>> case:
>> 
https://wiki.apache.org/tika/CompositeParserDiscussion#Supplementary.2FAdditive
>> And example Tika Config settings for it
>> https://wiki.apache.org/tika/CompositeParserDiscussion#line-20
>> If people are happy with how that sounds/looks, I can have a stab at
>> implementing it, as I *think* it's quite easy
>>
>>
>> However... that still leaves the Context (XHTML SAX events) case to 
solve!
>>
>> Anyone have any ideas on how we can append to or cancel/reset the 
Content
>> Handler series of SAX events when we move onto a second+ parser for 
a file?
>>
>> Thanks
>> Nick
>>
>>> On 10/26/17, 9:43 AM, "Nick Burch"  wrote:
>>>
>>>On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>>> My general approach to conflicting metadata is simply to define
>>>> precedence orders.
>>>>
>>>> For example here is one documented from OODT:
>>>>
>>>>
>>> 
https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence
>>>>
>>>> We can do similar things with Tika, e.g.,
>>>>
>>>> [CoreMetadata.PROPERTIES]
>>>> [ImageParser.METADATA]
>>>> [TikaOCR.METADATA]
>>>
>>>What happens if two different parsers both output the same bit of
>>> metadata
>>>though? eg Tim's example of one giving dc:creator of Tim and the 
second
>>>giving dc:creator of Chris?
>>>
>>>
>>>Secondly, what about the XHTML sax events stream? I think that's
>>> probably
>>>the harder case...
>>>
>>>Nick
>
>
>

Re: Not-yet-broken breaking changes for Tika 2?

2018-02-05 Thread Mattmann, Chris A (1761) 
Our solution is just to run the parser 2xyes I get it will induce overhead, 
but as a start, why not?
In short just run through the stream 2x

++
Chris Mattmann, Ph.D.
Associate Chief Technology and Innovation Officer, OCIO
Manager, Advanced IT Research and Open Source Projects Office (1761)
Manager, NSF and Open Source Programs and Applications Office (8212)
NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA
Office: 180-503E, Mailstop: 180-502
Email: chris.a.mattm...@nasa.gov
WWW:  http://sunset.usc.edu/~mattmann/
++
Director, Information Retrieval and Data Science Group (IRDS)
Adjunct Associate Professor, Computer Science Department
University of Southern California, Los Angeles, CA 90089 USA
WWW: http://irds.usc.edu/
++
 
 
On 2/5/18, 9:25 AM, "Nick Burch"  wrote:

On Mon, 5 Feb 2018, Chris Mattmann wrote:
> Let's have a go at implementing it! You know my thoughts (make it like 
> OODT ;) )\

I'm still keen to hear how we can do the text content like OODT!

I have tried to copy the OODT model for the proposed metadata case though 
:)

Nick

> On 2/5/18, 8:37 AM, "Nick Burch"  wrote:
>
>Ping - anyone got any thoughts on the proposed metadata parser stuff, 
and
>any ideas on the content part?
>
>On Tue, 2 Jan 2018, Nick Burch wrote:
>> On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>> On collision, the precedence order defines what key takes 
precedence and
>>> _overwrites_ the other. Overwrite is but one option (you could save 
*all*
>>> the values it’s a multi-valued key structure so…)
>>
>> OK, I think that's fine. I've had a go at updating the wiki for the 
metadata
>> case:
>> 
https://wiki.apache.org/tika/CompositeParserDiscussion#Supplementary.2FAdditive
>> And example Tika Config settings for it
>> https://wiki.apache.org/tika/CompositeParserDiscussion#line-20
>> If people are happy with how that sounds/looks, I can have a stab at
>> implementing it, as I *think* it's quite easy
>>
>>
>> However... that still leaves the Context (XHTML SAX events) case to 
solve!
>>
>> Anyone have any ideas on how we can append to or cancel/reset the 
Content
>> Handler series of SAX events when we move onto a second+ parser for 
a file?
>>
>> Thanks
>> Nick
>>
>>> On 10/26/17, 9:43 AM, "Nick Burch"  wrote:
>>>
>>>On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>>> My general approach to conflicting metadata is simply to define
>>>> precedence orders.
>>>>
>>>> For example here is one documented from OODT:
>>>>
>>>>
>>> 
https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence
>>>>
>>>> We can do similar things with Tika, e.g.,
>>>>
>>>> [CoreMetadata.PROPERTIES]
>>>> [ImageParser.METADATA]
>>>> [TikaOCR.METADATA]
>>>
>>>What happens if two different parsers both output the same bit of
>>> metadata
>>>though? eg Tim's example of one giving dc:creator of Tim and the 
second
>>>giving dc:creator of Chris?
>>>
>>>
>>>Secondly, what about the XHTML sax events stream? I think that's
>>> probably
>>>the harder case...
>>>
>>>Nick
>
>
>

Re: Not-yet-broken breaking changes for Tika 2?

2018-02-05 Thread Nick Burch 

On Mon, 5 Feb 2018, Chris Mattmann wrote:
Let's have a go at implementing it! You know my thoughts (make it like 
OODT ;) )\


I'm still keen to hear how we can do the text content like OODT!

I have tried to copy the OODT model for the proposed metadata case though 
:)


Nick


On 2/5/18, 8:37 AM, "Nick Burch"  wrote:

   Ping - anyone got any thoughts on the proposed metadata parser stuff, and
   any ideas on the content part?

   On Tue, 2 Jan 2018, Nick Burch wrote:
   > On Thu, 26 Oct 2017, Chris Mattmann wrote:
   >> On collision, the precedence order defines what key takes precedence and
   >> _overwrites_ the other. Overwrite is but one option (you could save *all*
   >> the values it’s a multi-valued key structure so…)
   >
   > OK, I think that's fine. I've had a go at updating the wiki for the 
metadata
   > case:
   > 
https://wiki.apache.org/tika/CompositeParserDiscussion#Supplementary.2FAdditive
   > And example Tika Config settings for it
   > https://wiki.apache.org/tika/CompositeParserDiscussion#line-20
   > If people are happy with how that sounds/looks, I can have a stab at
   > implementing it, as I *think* it's quite easy
   >
   >
   > However... that still leaves the Context (XHTML SAX events) case to solve!
   >
   > Anyone have any ideas on how we can append to or cancel/reset the Content
   > Handler series of SAX events when we move onto a second+ parser for a file?
   >
   > Thanks
   > Nick
   >
   >> On 10/26/17, 9:43 AM, "Nick Burch"  wrote:
   >>
   >>On Thu, 26 Oct 2017, Chris Mattmann wrote:
   >>> My general approach to conflicting metadata is simply to define
   >>> precedence orders.
   >>>
   >>> For example here is one documented from OODT:
   >>>
   >>>
   >> 
https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence
   >>>
   >>> We can do similar things with Tika, e.g.,
   >>>
   >>> [CoreMetadata.PROPERTIES]
   >>> [ImageParser.METADATA]
   >>> [TikaOCR.METADATA]
   >>
   >>What happens if two different parsers both output the same bit of
   >> metadata
   >>though? eg Tim's example of one giving dc:creator of Tim and the second
   >>giving dc:creator of Chris?
   >>
   >>
   >>Secondly, what about the XHTML sax events stream? I think that's
   >> probably
   >>the harder case...
   >>
   >>Nick

Re: Not-yet-broken breaking changes for Tika 2?

2018-02-05 Thread Chris Mattmann 
Let's have a go at implementing it! You know my thoughts (make it like OODT ;) 
)\



On 2/5/18, 8:37 AM, "Nick Burch"  wrote:

Ping - anyone got any thoughts on the proposed metadata parser stuff, and 
any ideas on the content part?

On Tue, 2 Jan 2018, Nick Burch wrote:
> On Thu, 26 Oct 2017, Chris Mattmann wrote:
>> On collision, the precedence order defines what key takes precedence and 
>> _overwrites_ the other. Overwrite is but one option (you could save 
*all* 
>> the values it’s a multi-valued key structure so…)
>
> OK, I think that's fine. I've had a go at updating the wiki for the 
metadata 
> case:
> 
https://wiki.apache.org/tika/CompositeParserDiscussion#Supplementary.2FAdditive
> And example Tika Config settings for it
> https://wiki.apache.org/tika/CompositeParserDiscussion#line-20
> If people are happy with how that sounds/looks, I can have a stab at 
> implementing it, as I *think* it's quite easy
>
>
> However... that still leaves the Context (XHTML SAX events) case to solve!
>
> Anyone have any ideas on how we can append to or cancel/reset the Content 
> Handler series of SAX events when we move onto a second+ parser for a 
file?
>
> Thanks
> Nick
>
>> On 10/26/17, 9:43 AM, "Nick Burch"  wrote:
>>
>>On Thu, 26 Oct 2017, Chris Mattmann wrote:
>>> My general approach to conflicting metadata is simply to define
>>> precedence orders.
>>>
>>> For example here is one documented from OODT:
>>>
>>> 
>> 
https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence
>>>
>>> We can do similar things with Tika, e.g.,
>>>
>>> [CoreMetadata.PROPERTIES]
>>> [ImageParser.METADATA]
>>> [TikaOCR.METADATA]
>>
>>What happens if two different parsers both output the same bit of 
>> metadata
>>though? eg Tim's example of one giving dc:creator of Tim and the 
second
>>giving dc:creator of Chris?
>> 
>>
>>Secondly, what about the XHTML sax events stream? I think that's 
>> probably
>>the harder case...
>>
>>Nick

Re: Not-yet-broken breaking changes for Tika 2?

2018-02-05 Thread Nick Burch 
Ping - anyone got any thoughts on the proposed metadata parser stuff, and 
any ideas on the content part?


On Tue, 2 Jan 2018, Nick Burch wrote:

On Thu, 26 Oct 2017, Chris Mattmann wrote:
On collision, the precedence order defines what key takes precedence and 
_overwrites_ the other. Overwrite is but one option (you could save *all* 
the values it’s a multi-valued key structure so…)


OK, I think that's fine. I've had a go at updating the wiki for the metadata 
case:

https://wiki.apache.org/tika/CompositeParserDiscussion#Supplementary.2FAdditive
And example Tika Config settings for it
https://wiki.apache.org/tika/CompositeParserDiscussion#line-20
If people are happy with how that sounds/looks, I can have a stab at 
implementing it, as I *think* it's quite easy



However... that still leaves the Context (XHTML SAX events) case to solve!

Anyone have any ideas on how we can append to or cancel/reset the Content 
Handler series of SAX events when we move onto a second+ parser for a file?


Thanks
Nick


On 10/26/17, 9:43 AM, "Nick Burch"  wrote:

   On Thu, 26 Oct 2017, Chris Mattmann wrote:
   > My general approach to conflicting metadata is simply to define
   > precedence orders.
   >
   > For example here is one documented from OODT:
   >
   > 
https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence

   >
   > We can do similar things with Tika, e.g.,
   >
   > [CoreMetadata.PROPERTIES]
   > [ImageParser.METADATA]
   > [TikaOCR.METADATA]

   What happens if two different parsers both output the same bit of 
metadata

   though? eg Tim's example of one giving dc:creator of Tim and the second
   giving dc:creator of Chris?


   Secondly, what about the XHTML sax events stream? I think that's 
probably

   the harder case...

   Nick

Re: Not-yet-broken breaking changes for Tika 2?

2018-01-02 Thread Nick Burch 

Sorry to ignore this for so long...

On Thu, 26 Oct 2017, Chris Mattmann wrote:
On collision, the precedence order defines what key takes precedence and 
_overwrites_ the other. Overwrite is but one option (you could save 
*all* the values it’s a multi-valued key structure so…)


OK, I think that's fine. I've had a go at updating the wiki for the 
metadata case:

https://wiki.apache.org/tika/CompositeParserDiscussion#Supplementary.2FAdditive
And example Tika Config settings for it
https://wiki.apache.org/tika/CompositeParserDiscussion#line-20
If people are happy with how that sounds/looks, I can have a stab at 
implementing it, as I *think* it's quite easy



However... that still leaves the Context (XHTML SAX events) case to solve!

Anyone have any ideas on how we can append to or cancel/reset the Content 
Handler series of SAX events when we move onto a second+ parser for a 
file?


Thanks
Nick


On 10/26/17, 9:43 AM, "Nick Burch"  wrote:

   On Thu, 26 Oct 2017, Chris Mattmann wrote:
   > My general approach to conflicting metadata is simply to define
   > precedence orders.
   >
   > For example here is one documented from OODT:
   >
   > 
https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence
   >
   > We can do similar things with Tika, e.g.,
   >
   > [CoreMetadata.PROPERTIES]
   > [ImageParser.METADATA]
   > [TikaOCR.METADATA]

   What happens if two different parsers both output the same bit of metadata
   though? eg Tim's example of one giving dc:creator of Tim and the second
   giving dc:creator of Chris?


   Secondly, what about the XHTML sax events stream? I think that's probably
   the harder case...

   Nick

Re: Not-yet-broken breaking changes for Tika 2?

2017-10-26 Thread Chris Mattmann 
On collision, the precedence order defines what key takes precedence and 
_overwrites_ the
other. Overwrite is but one option (you could save *all* the values it’s a 
multi-valued key structure
so…)

Cheers,
Chris




On 10/26/17, 9:43 AM, "Nick Burch"  wrote:

On Thu, 26 Oct 2017, Chris Mattmann wrote:
> My general approach to conflicting metadata is simply to define 
> precedence orders.
>
> For example here is one documented from OODT:
>
> 
https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence
>
> We can do similar things with Tika, e.g.,
>
> [CoreMetadata.PROPERTIES]
> [ImageParser.METADATA]
> [TikaOCR.METADATA]

What happens if two different parsers both output the same bit of metadata 
though? eg Tim's example of one giving dc:creator of Tim and the second 
giving dc:creator of Chris?


Secondly, what about the XHTML sax events stream? I think that's probably 
the harder case...

Nick

Re: Not-yet-broken breaking changes for Tika 2?

2017-10-26 Thread Nick Burch 

On Thu, 26 Oct 2017, Chris Mattmann wrote:
My general approach to conflicting metadata is simply to define 
precedence orders.


For example here is one documented from OODT:

https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence

We can do similar things with Tika, e.g.,

[CoreMetadata.PROPERTIES]
[ImageParser.METADATA]
[TikaOCR.METADATA]


What happens if two different parsers both output the same bit of metadata 
though? eg Tim's example of one giving dc:creator of Tim and the second 
giving dc:creator of Chris?



Secondly, what about the XHTML sax events stream? I think that's probably 
the harder case...


Nick

Re: Not-yet-broken breaking changes for Tika 2?

2017-10-26 Thread Chris Mattmann 
Thanks Nick.

My general approach to conflicting metadata is simply to define precedence 
orders.

For example here is one documented from OODT:

https://cwiki.apache.org/confluence/display/OODT/Understanding+CAS-PGE+Metadata+Precendence
 

We can do similar things with Tika, e.g.,

[CoreMetadata.PROPERTIES]
[ImageParser.METADATA]
[TikaOCR.METADATA]
…

And then start with the top, and then overlay heading downwards. Make sense?

Cheers,
Chris

P.S. The metadata key/value merging principles could be configurable, but a 
default base one of
overlay according to some configured precedence order maybe in tika-config.xml 
would be a fine
start.




On 10/26/17, 9:14 AM, "Nick Burch"  wrote:

On Thu, 26 Oct 2017, Chris Mattmann wrote:
> Why don’t we just store N copies of the stream, and parse it twice?

I'm not sure that's the challenge though? Using TikaInputStream we can 
buffer to a temp file if needed to re-read the input

> Of course that’s the ugly way, but currently the way I’ve hacked this in 
> all of my projects is simply to call Tika N times OUTSIDE of Tika. Why 
> don’t we just use that as the weakest baseline and work backwards from 
> there?

I think our main challenge right now is on the output end. How do you deal 
with multiple different Metadata results that might clash after running 
Tika server times? How do you deal with multiple (some potentially empty, 
some overlapping) XHTML outputs from multiple parses? Can we copy those 
approaches?

Thanks
Nick

Re: Not-yet-broken breaking changes for Tika 2?

2017-10-26 Thread Nick Burch 

On Thu, 26 Oct 2017, Chris Mattmann wrote:

Why don’t we just store N copies of the stream, and parse it twice?


I'm not sure that's the challenge though? Using TikaInputStream we can 
buffer to a temp file if needed to re-read the input


Of course that’s the ugly way, but currently the way I’ve hacked this in 
all of my projects is simply to call Tika N times OUTSIDE of Tika. Why 
don’t we just use that as the weakest baseline and work backwards from 
there?


I think our main challenge right now is on the output end. How do you deal 
with multiple different Metadata results that might clash after running 
Tika server times? How do you deal with multiple (some potentially empty, 
some overlapping) XHTML outputs from multiple parses? Can we copy those 
approaches?


Thanks
Nick

Re: Not-yet-broken breaking changes for Tika 2?

2017-10-26 Thread Chris Mattmann 
Why don’t we just store N copies of the stream, and parse it twice?

Of course that’s the ugly way, but currently the way I’ve hacked this in all of
my projects is simply to call Tika N times OUTSIDE of Tika. Why don’t we just 
use
that as the weakest baseline and work backwards from there?

Chris




On 10/26/17, 3:56 AM, "Nick Burch"  wrote:

Hi All

Based on the plan on the wiki 
 
, we still have a 
major breaking change or two planned for Tika 2 that we haven't yet 
"broken". (There's also removing some deprecated stuff etc)


As I understand it, the biggest breaking TODO change is around having 
multiple parsers available + active for a given format. This could be to 
support fallback parsers, eg "try this fancy new parser, but if it falls 
retry with this simpler one" or "try this xml parser, if that fails just 
try strings". A related but different case is to cleanly support multiple 
parsers covering different aspects, eg OCR an image plus extract metadata, 
or NER on the contents of a scientific PDF + text + metadata + NER of the 
OCR of embedded images in the PDF.

Currently, we can't cleanly do the former, and the latter is (badly) 
handled via one parser (eg OCR or NER) having an embedded hard-code 
reference to another (eg Image or PDF).


We've got some details on the proposed plans and ideas on the wiki:
https://wiki.apache.org/tika/CompositeParserDiscussion

The biggest stumbling block, as I see it, is how to let multiple parsers 
interact with the SAX content handler. For the fallback case, that's how 
to say "sorry, ignore all that XML we already sent, we're starting again 
with this XML now". For the multiple parser case, it's how we could have 
the image parser "finish" the (empty) XHTML but then have the OCR one send 
some text, or have the NER parser get at the XHTML text of the PDF + OCR 
of embedded images to enhance with the entities.


What do we think for this? Can we come up with a solution to let this go 
forward? Is there a pattern from elsewhere we can follow?

Or do we need to cancel this for 2.x, ponder it for another 1-2 years, and 
do this stuff in Tika 3 instead?

Nick

RE: Not-yet-broken breaking changes for Tika 2?

2017-10-26 Thread Allison, Timothy B. 
At this point, I'm willing to punt to 3.x, unless there's momentum for either 
of these two.  They would be great to have!

1) chaining multiple parsers -- additive
This shouldn't be too bad, except where there's conflicting metadata -- parser1 
says author is 'bob', parser2 says author is 'alice'.  We would break some 
uniqueness guarantees for some Properties that should only allow a single value 
if we added those values...  Overwriting feels like a bad idea.  Perhaps we 
remove the uniqueness guarantees when in "additive" mode ... or let users 
select additive/overwrite?

2) fallback parsers 
>The biggest stumbling block, as I see it, is how to let multiple parsers 
>interact with the SAX content handler. For the fallback case, that's how to 
>say "sorry, ignore all that XML we already sent, we're starting again with 
>this XML now".

Y, this has been what's holding me back.  How do we create a resettable handler 
that doesn't have us mucking too much with all of our current handlers.  For 
those with outputstreams/writers,  I imagine we'd require a resettable 
OutputStream...TikaOutputStream(?)

TikaOutputStream() --underling stringwriter, when reset, would just be a new 
stringwriter on reset() ??? Not quite right...
TikaOutputStream.get(Path/File) -- would hold the underlying file/path, close 
the writer, and just rewrite on reset()
TikaOutputStream.get(ByteArrayOutputStream)  baos has a reset() so that should 
work...

What other use cases?




-Original Message-
From: Nick Burch [mailto:n...@apache.org] 
Sent: Thursday, October 26, 2017 6:57 AM
To: dev@tika.apache.org
Subject: Not-yet-broken breaking changes for Tika 2?

Hi All

Based on the plan on the wiki

, we still have a major 
breaking change or two planned for Tika 2 that we haven't yet "broken". 
(There's also removing some deprecated stuff etc)


As I understand it, the biggest breaking TODO change is around having multiple 
parsers available + active for a given format. This could be to support 
fallback parsers, eg "try this fancy new parser, but if it falls retry with 
this simpler one" or "try this xml parser, if that fails just try strings". A 
related but different case is to cleanly support multiple parsers covering 
different aspects, eg OCR an image plus extract metadata, or NER on the 
contents of a scientific PDF + text + metadata + NER of the OCR of embedded 
images in the PDF.

Currently, we can't cleanly do the former, and the latter is (badly) handled 
via one parser (eg OCR or NER) having an embedded hard-code reference to 
another (eg Image or PDF).


We've got some details on the proposed plans and ideas on the wiki:
https://wiki.apache.org/tika/CompositeParserDiscussion

The biggest stumbling block, as I see it, is how to let multiple parsers 
interact with the SAX content handler. For the fallback case, that's how to say 
"sorry, ignore all that XML we already sent, we're starting again with this XML 
now". For the multiple parser case, it's how we could have the image parser 
"finish" the (empty) XHTML but then have the OCR one send some text, or have 
the NER parser get at the XHTML text of the PDF + OCR of embedded images to 
enhance with the entities.


What do we think for this? Can we come up with a solution to let this go 
forward? Is there a pattern from elsewhere we can follow?

Or do we need to cancel this for 2.x, ponder it for another 1-2 years, and do 
this stuff in Tika 3 instead?

Nick