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Nanite - a friendly swarm of format-identifying robots

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Nanite logo

The Nanite project builds on DROID and Apache Tika to provide a rich format identification and characterization system. It aims to make it easier to run identification and characterisation at scale, and helps compare and combine the results of different tools.

  • nanite-core contains the core identification code, a wrapped version of DROID that can parse InputStreams.
  • nanite-historical-sigs contains old versions of the DROID signature files.

Nanite has been used at scale, see this blog post

Using DROID Directly

At first, this project was necessary because the way DROID was written made it difficult to re-use the core format identification code. This has improved over the years, meaning more code could be deleted from this project and replaced with calls to standard DROID code.

As of DROID 6.6.0, there is now 'internal' API that can be used instead of Nanite. If you just need simple identification of files, you should consider using that instead (while keeping in mind that the API itself is not yet stable).

Nanite extends the DROID API code to make it work on InputStreams, and to a little more information about the formats accessible via the API. It provides this extended API as an Apache Tika Detector, acting as a stable alternative API.

Hopefully, as the offical DROID API evolves, this project can be reduced to being just a Apache Tika compatibility wrapper/shim.

Using the Nanite API

Since version 1.3.1-90 of nanite-core, a new API has been introduced to make it possible to get the PUID-level data out, as an alternative to only being able to access the extended MIME type. This was modified slightly in version 1.5.0.

First add the nanite-core dependency to your Java project, e.g. for Maven:


Then from your code, you can use this to identify an input stream :

    DroidDetector dd = new DroidDetector();
    Metadata metadata = new Metadata();
    metadata.set(Metadata.RESOURCE_NAME_KEY, "filename");
    MediaType droidType = dd.detect(inputstream, metadata);

You can also tweak the DROID configuration if you wish. e.g. this configuration only uses binary signatures, but allows DROID to scan all the bytes in the bytestream:

    dd.setBinarySignaturesOnly( true );
    dd.setMaxBytesToScan( -1 );

You can use the Tika-compatible detect method to get a MediaType. This assembles the DROID result into an extended MIME type. Where a format has a known MIME type, this means adding the version to it, like this: application/pdf; version="1.4". Formats with no known MIME type use a constructed one of the form: application/x-puid-fmt-111; name="OLE2 Compound Document Format". The format results are also added to the Tika Metadata results as nanite:format values, e.g. nanite:format = info:pronom/fmt/12.

Alternatively, you can use the identify method to get a DROID ApiResult and use the PUID directly, like this:

        // Create a DroidDetector using the default build-in sig file:
        DroidDetector dd = new DroidDetector();
		// Can use a File or an InputStream:
		File inFile = new File("src/test/resources/lorem-ipsum.doc");

		// If you use the InputStream, you need to add the resource name if you
		// want extension-based identification to work:
		Metadata metadata = new Metadata();
		metadata.set(TikaCoreProperties.RESOURCE_NAME_KEY, inFile.toURI().toString());

		// To get the identification as an extended MIME type:
		MediaType mt = dd.detect(inFile);
		// Or:
		mt = dd.detect(new FileInputStream(inFile), metadata);
		// Giving:
		// MIME Type: application/msword; version=97-2003
		System.out.println("MIME Type: " + mt);
		for( String value: metadata.getValues(DroidDetector.PUID)) {
			System.out.println("- "+DroidDetector.PUID.getName()+" = "+ value);

		// Or, get the raw DROID results
		List<ApiResultExtended> lir = dd.identify(inFile);
		for (ApiResultExtended ir : lir) {

			System.out.println("PUID: " + ir.getPuid() + " '" + ir.getName()
					+ "' " + ir.getVersion() + " (" + ir.getMimeType()
					+ ") via " + ir.getMethod() + " identification.");
			// PUID: fmt/40 'Microsoft Word Document' 97-2003
			// (application/msword) via Container identification.

			// Which you can then turn into an extended MIME type if required:
			System.out.println("Extended MIME:"
					+ dd.getMimeTypeFromResult(ir));
			// Extended MIME:application/msword; version=97-2003

The DroidDetector is not thread-safe, and multi-threaded processes should have a separate instance of the DroidDetector for each thread. e.g. by using a ThreadLocal instance.

		ThreadLocal<DroidDetector> threadLocal = new ThreadLocal<>();
		if (threadLocal.get() == null) {
			threadLocal.set(new DroidDetector());
		DroidDetector dd = threadLocal.get();


The Nanite system deliberately embeds a copy of the latest PRONOM signature files at the time of release, with the -XX part of the version number tracking the PRONOM release number. i.e. 1.5.0-111 includes PRONOM signature file version 111 and the corresponding container signatures.

Nanite does not support auto-updating the signature files, but if you wish, you can download them and pass them to the DroidDetector via the DroidDetector(File fileSignaturesFile, File containerSignaturesFile) constructor.

Change Log

Version numbers are like x.x.x-yy - changes to the yy refer to updates to the PRONOM signature files, whereas changes to the x.x.x part refer to changes to the code that uses them. Only the latter are recorded here:

  • 1.5.0
    • Major changes and simpler code due to upgrading to use DROID 6.6's droid-api module.
    • Updated signature files to v111 / 20230307.
    • Dropped nanite-hadoop module as maintenane overhead is large and it's not in use. Use webarchive-discovery instead.
  • 1.4.1
    • Updates to how temporary files are handled, attempting to ensure large sets of temporary files are not left in place unnecessarily.
  • 1.4.0
    • Significant update to the implementation to take advantage of improvements in DROID 6.5. DROID's improved API means less code is required to run it in Nanite.
  • 1.3.2-83
    • Updated DROID binary (and container) signatures to v83.
  • 1.3.1
    • Revert to not falling back on extension-based identification by default, as enabling this is a breaking API change.
  • 1.3.0
    • As of this release, the DROID code for guessing based on file extension is also included by default, if binary signature detection fails. New parameters on the DroidDetector allow this to be controlled.


This work was partially supported by the SCAPE project. The SCAPE project is co-funded by the European Union under FP7 ICT-2009.4.1 (Grant Agreement number 270137)