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ALF-4448 - If a transformation fails, ask Tika if the mime type looks plausible, and if Tika thinks not, include the suggested real mime type in the exception

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git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@22777 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261
This commit is contained in:
Nick Burch
2010-09-29 17:09:09 +00:00
parent 6da3dd1937
commit 0105f86127
1 changed files with 78 additions and 5 deletions
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83
source/java/org/alfresco/repo/content/transform/AbstractContentTransformer2.java
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@@ -27,6 +27,9 @@ import org.alfresco.service.cmr.repository.ContentWriter;
import org.alfresco.service.cmr.repository.TransformationOptions;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.tika.config.TikaConfig;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
/**
* Provides basic services for {@link org.alfresco.repo.content.transform.ContentTransformer}
@@ -46,6 +49,8 @@ public abstract class AbstractContentTransformer2 extends ContentTransformerHelp
private double averageTime = 0.0;
private long count = 0L;
private TikaConfig tikaConfig;
/**
* All transformers start with an average transformation time of 0.0ms.
*/
@@ -167,11 +172,29 @@ public abstract class AbstractContentTransformer2 extends ContentTransformerHelp
// will be prejudiced against transformers that tend to fail
recordTime(60 * 1000); // 1 minute, i.e. rubbish
throw new ContentIOException("Content conversion failed: \n" +
" reader: " + reader + "\n" +
" writer: " + writer + "\n" +
" options: " + options,
e);
// Ask Tika to detect the document, and report back on if
// the current mime type is plausible
String differentType = checkMimeTypeMatches(reader.getReader());
// Report the error
if(differentType == null)
{
throw new ContentIOException("Content conversion failed: \n" +
" reader: " + reader + "\n" +
" writer: " + writer + "\n" +
" options: " + options,
e);
}
else
{
throw new ContentIOException("Content conversion failed: \n" +
" reader: " + reader + "\n" +
" writer: " + writer + "\n" +
" options: " + options + "\n" +
" claimed mime type: " + reader.getMimetype() + "\n" +
" detected mime type: " + differentType,
e);
}
}
finally
{
@@ -246,4 +269,54 @@ public abstract class AbstractContentTransformer2 extends ContentTransformerHelp
double diffTime = ((double) transformationTime) - averageTime;
averageTime += diffTime / (double) count;
}
/**
* Use Apache Tika to check if the mime type of the document really matches
* what it claims to be.
* This is typically used when a transformation fails, and you want to know
* if someone has renamed a file and consequently it has the wrong mime type.
* @return Null if the mime type seems ok, otherwise the mime type it probably is
*/
protected String checkMimeTypeMatches(ContentReader reader)
{
if(tikaConfig == null)
{
try {
tikaConfig = TikaConfig.getDefaultConfig();
} catch(Exception e) {
logger.warn("Error creating Tika detector", e);
return null;
}
}
Metadata metadata = new Metadata();
MediaType type;
try {
type = tikaConfig.getMimeRepository().detect(
reader.getContentInputStream(), metadata
);
logger.debug(reader + " detected by Tika as being " + type.toString());
} catch(Exception e) {
logger.warn("Error identifying content type of problem document", e);
return null;
}
// Is it a good match?
if(type.toString().equals(reader.getMimetype()))
{
return null;
}
// Is it close?
MediaType claimed = MediaType.parse(reader.getMimetype());
if(tikaConfig.getMediaTypeRegistry().isSpecializationOf(claimed, type) ||
tikaConfig.getMediaTypeRegistry().isSpecializationOf(type, claimed))
{
// Probably close enough
return null;
}
// If we get here, then most likely the type is wrong
return type.toString();
}
}