One of the great joys of development comes when you learn about a program making your development task very simple.  Apache Tika is one of those programs, and before I even begin to talk about Tika, I have to tip my hat to the developers.  Thank you very much for making my job simpler.

So, what is Tika?

Tika reads the context and content of almost any file so your programs can consume it.  Tika is commonly used for those working with eDiscovery, Taxonomy generation, content capture, and indexing for content management systems. Basically, anytime you want your application to understand all there is about a file, or URI look to Tika to convert it for you.

Tika initially was designed as a part of the Apache Lucene project which is used to automatically index files for full text index searches.  Tika has been around for several years now, but remains a very active application due to the task it was designed for and how well it was written.

The great thing about Tika is you don’t have to know what the file type is for Tika to parse it.  Tika determines the file type for you based on the files header or by extensions. It then uses its built-in parsers to read the file.

How easy is Tika?

Below is the section of my code that implements Tika version 1.4.

	public String parseToString(File givenFile) throws IOException, TikaException{
		Tika myTika = new Tika();
		return myTika.parseToString(givenFile);
	}

Yep, that is parsed content in two simple lines of code.  Now, mind you, I was only interested in getting the content of the file in a text format, but that simplicity is what I am grateful for.  Tika, in all of its facets, is simple to use while remaining very versatile. (Note: When testing this code, make certain the file actually has readable content.  A TIFF or a MP3 file generally does not contain content to be parsed, so you won’t see anything.)

Other ways of using Tika

Okay so maybe you want a little bit more information from a File, like fetching the extra metadata found in a file header.  To complete this task some extra steps are needed, but are well documented. Below is an example of fetching metadata from a file.  In the case below, I’m generating a JSONObject of name-value pairs for the metadata so I the application can consume the metadata later.

public JSONObject fetchMetaData(File givenFile) throws IOException {

		JSONObject jsonMetaData = new JSONObject();

		Metadata metadata = new Metadata();
		Tika myTika = new Tika();

		InputStream instream = new FileInputStream(givenFile);

		myTika.parse(instream, metadata);

		 for (String metaKey : metadata.names()) {
			 String metaValue = metadata.get(metaKey);

			 jsonMetaData.put(metaKey, metaValue);
		}

		return jsonMetaData;
	}

Now maybe you want to fetch both metadata and content, then below uses the Tika classes to fetch both at one time.  That way you only make one pass on the File or inputstream:

public String getEverything(File givenFile) throws IOException, SAXException, TikaException {

		JSONObject jsonMetaData = new JSONObject();
		ContentHandler handler = new BodyContentHandler();

		Metadata metadata = new Metadata();
		Parser parser = new AutoDetectParser();
		InputStream instream = new FileInputStream(givenFile);
		ParseContext parsedContent = new ParseContext();

		parser.parse(instream, handler, metadata, parsedContent);

		 for (String metaKey : metadata.names()) {
			 String metaValue = metadata.get(metaKey);

			 jsonMetaData.put(metaKey, metaValue);
		}

		// Return string
		return jsonMetaData.toJSONString() + "\n\n" + handler.toString();
	}

 

More Tika Documentation and Examples

https://tika.apache.org/index.html

https://tika.apache.org/1.4/gettingstarted.html

https://www.openlogic.com/wazi/bid/314389/Content-mining-with-Apache-Tika

https://mvnrepository.com/artifact/org.apache.tika/tika-parsers/1.4