My $0.02 would be to use TikaInputStream because that gets a lot more use
and is battle-tested. Within the last year or so, we started using
RereadableInputStream in one of the Microsoft format parsers so it is also
getting some use now.
If you absolutely can't afford to spool to disk, then give
RereadableInputStream a try.
The inputstreamfactories, in my mind, are somewhat work-arounds for other
use cases, e.g. retrying/batch etc.
On Tue, Feb 23, 2021 at 11:41 AM Peter Kronenberg <peter.kronenb...@torch.ai>
wrote:
> So this might be moot, because it seems that TikaInputStream is already
> doing some magic and I’m not sure how.
>
> I was able to re-use the stream without doing anything special after a
> call to parse. And in fact, I displayed stream.available() and
> stream.position() before and after the call to parse, and the full stream
> was still available at position 0. What is TikaInputStream doing to make
> this happen?
>
>
>
> Just for some additional context, what I’m doing is running the file
> through Tika and then, depending on the file type, I want to do some
> additional non-tika processing. I thought that once the Tika parse was
> done, the stream would be used up.
>
>
>
> What is going on?
>
>
>
>
>
> *From:* Peter Kronenberg <peter.kronenb...@torch.ai>
> *Sent:* Tuesday, February 23, 2021 10:00 AM
> *To:* user@tika.apache.org; lfcnas...@gmail.com
> *Subject:* RE: Re-using a TikaStream
>
>
>
> This email was sent from outside your organisation, yet is displaying the
> name of someone from your organisation. This often happens in phishing
> attempts. Please only interact with this email if you know its source and
> that the content is safe.
>
>
>
> I just found the RereadableInputStream. This looks more like what I was
> thinking. Is there any reason not to use it? What are the Tika best
> practices? Pros/Cons of each approach? If RereadableInputStream works as
> it’s supposed to, I’m not sure I see the advantage of InputStreamFactory
>
>
>
> *From:* Peter Kronenberg <peter.kronenb...@torch.ai>
> *Sent:* Monday, February 22, 2021 8:30 PM
> *To:* lfcnas...@gmail.com
> *Cc:* user@tika.apache.org
> *Subject:* RE: Re-using a TikaStream
>
>
>
> This email was sent from outside your organisation, yet is displaying the
> name of someone from your organisation. This often happens in phishing
> attempts. Please only interact with this email if you know its source and
> that the content is safe.
>
>
>
> Oh ok. I didn’t realize I needed to write my own class to implement it. I
> was looking for some sort of existing framework.
>
>
>
> What is the purpose of the 2 InputStreamFactory classes:
>
>
>
> I was re-reading some emails with Nick Burch back around Dec 22-23 and
> maybe I mis-understood him, but it sounds like he was saying that
> TiksInputStream was smart enough to automatically spool the stream to disk
> to allow re-use.
>
>
>
> It seems to me that I need an extra pass through the data in order to save
> to disk. I’m not starting from a File, but from a stream. So if I need to
> read the stream twice, I really have to pass through the data 3 times,
> correct?
>
> Unless there is a way to save to disk during the first pass
>
>
>
> (try/catch removed for simplicity)
>
>
>
> tis = TikaInputSream.get(InputStream);
>
> file = tis.getFile(); ç extra pass
>
> tis = TikaInputStream.get(new MyInputStreamFactory(file));
>
> // first real pass
>
> InputStream is = tis.getInputStreamFactory().getInputStream()
>
> // second real pass
>
> }
>
>
>
>
>
>
>
> *From:* Luís Filipe Nassif <lfcnas...@gmail.com>
> *Sent:* Monday, February 22, 2021 5:42 PM
> *To:* Peter Kronenberg <peter.kronenb...@torch.ai>
> *Cc:* user@tika.apache.org
> *Subject:* Re: Re-using a TikaStream
>
>
>
> Something like:
>
>
>
> class MyInputStreamFactory implements InputStreamFactory{
>
>
>
> private File file;
>
>
>
> public MyInputStreamFactory(File file){
>
> this.file = file;
>
> }
>
>
>
> public InputStream getInputStream(){
>
> return new FileInputStream(file);
>
> }
>
> }
>
>
>
> in your client code:
>
>
>
> Parser parser = new AutoDetectParser();
>
> TikaInputStream tis = TikaInputStream.get(new MyInputStreamFactory(file));
>
> parser.parse(tis, new ToTextContentHandler(), new Metadata(), new
> ParseContext());
>
>
>
> when you need to reuse the stream (into your parser):
>
>
>
> public void parse(InputStream stream, ContentHandler handler, Metadata
> metadata, ParseContext context)
> throws IOException, SAXException, TikaException {
>
> //(...)
>
> TikaInputStream tis = TikaInputStream.get(stream);
>
> if(tis.hasInputStreamFactory()){
>
> try(InputStream is = tis.getInputStreamFactory().getInputStream()){
>
> //consume the new stream
>
> }
>
> }else
>
> throw new IOException("not a reusable inputStream");
>
> }
>
>
>
> Of course this is useful if you are not processing files, e.g. reading
> files from the cloud or sockets.
>
>
>
> Regards,
>
> Luis
>
>
>
>
>
> Em seg., 22 de fev. de 2021 às 19:18, Peter Kronenberg <
> peter.kronenb...@torch.ai> escreveu:
>
> I sent this question late on Friday. Sending it again. Can you provide a
> little more information how out to use the InputStreamFactory?
>
>
>
> *From:* Peter Kronenberg <peter.kronenb...@torch.ai>
> *Sent:* Friday, February 19, 2021 5:10 PM
> *To:* user@tika.apache.org; lfcnas...@gmail.com
> *Subject:* RE: Re-using a TikaStream
>
>
>
> This email was sent from outside your organisation, yet is displaying the
> name of someone from your organisation. This often happens in phishing
> attempts. Please only interact with this email if you know its source and
> that the content is safe.
>
>
>
> There appear to be 2 InputStreamFactory classes: in tika-server-core and
> tika-io. The one in server.core is the only one with a concrete class.
>
> I’m not quite sure I see how to use this.
>
> Normally, I create a TikaInputStream with
> TikaInputStream.get(InputStream). How do I create it from an
> InputStreamFactory?
>
> TikaInputStream.getInputStreamFactory() only returns a factory if the
> TikaInputStream was created from a factory.
>
> Is there a good example of how this is used
>
>
>
> *From:* Peter Kronenberg <peter.kronenb...@torch.ai>
> *Sent:* Friday, February 19, 2021 4:57 PM
> *To:* user@tika.apache.org; lfcnas...@gmail.com
> *Subject:* RE: Re-using a TikaStream
>
>
>
> This email was sent from outside your organisation, yet is displaying the
> name of someone from your organisation. This often happens in phishing
> attempts. Please only interact with this email if you know its source and
> that the content is safe.
>
>
>
> Thanks. I thought that TikaInputStream already automatically saved to
> disk to allow re-reading.
>
>
>
> *From:* Luís Filipe Nassif <lfcnas...@gmail.com>
> *Sent:* Friday, February 19, 2021 3:44 PM
> *To:* user@tika.apache.org
> *Subject:* Re: Re-using a TikaStream
>
>
>
> You could call TikaInputStream.getPath() at the beginning of your parser,
> it will spool to file if not file based. After consuming the original
> inputStream, create a new one from the temp file created.
>
>
>
> If you are using 2.0.0-ALPHA, there is:
>
>
>
>
> https://github.com/apache/tika/blob/main/tika-core/src/main/java/org/apache/tika/io/InputStreamFactory.java
>
>
>
> Use with the new methods from TikaInputStream:
>
> public static TikaInputStream get(InputStreamFactory factory)
>
> public InputStreamFactory getInputStreamFactory()
>
>
>
> Hope this helps,
>
> Luis
>
>
>
> Em sex., 19 de fev. de 2021 às 16:09, Peter Kronenberg <
> peter.kronenb...@torch.ai> escreveu:
>
> If I finish parsing a TikaStream, can I re-use the stream (before it is
> closed)? I know you said that there is some magic behind the scenes where
> it spools it to a file. Can I just call reset() to start from the
> beginning?
>
>
>
> Peter
>
>
>
>
>
> *Peter Kronenberg* *| * *Senior AI Analytic ENGINEER *
>
> *C: 703.887.5623*
>
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