org.apache.nutch.util

## Class MimeUtil

- java.lang.Object
- - org.apache.nutch.util.MimeUtil

-     public final class MimeUtil
      extends Object

  Since:
    NUTCH-608

    This is a facade class to insulate Nutch from its underlying Mime Type substrate library, Apache Tika. Any mime handling code should be placed in this utility class, and hidden from the Nutch classes that rely on it.

  Author:
    mattmann

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `MimeUtil(Configuration conf)`

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `String` | `autoResolveContentType(String typeName, String url, byte[] data)` A facade interface to trying all the possible mime type resolution strategies available within Tika.
    `static String` | `cleanMimeType(String origType)` Cleans a `MimeType` name by removing out the actual `MimeType`, from a string of the form:
    `String` | `forName(String name)` A facade interface to Tika's underlying `MimeTypes.forName(String)` method.
    `String` | `getMimeType(File f)` Facade interface to Tika's underlying `MimeTypes.getMimeType(File)` method.
    `String` | `getMimeType(String url)` Facade interface to Tika's underlying `MimeTypes.getMimeType(String)` method.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### MimeUtil

          public MimeUtil(Configuration conf)

  - ### Method Detail

    - #### cleanMimeType

          public static String cleanMimeType(String origType)

      Cleans a `MimeType` name by removing out the actual `MimeType`, from a string of the form:

                <primary type>/<sub type> ; < optional params

      Parameters:
        `origType` - The original mime type string to be cleaned.
      Returns:
        The primary type, and subtype, concatenated, e.g., the actual mime type.

    - #### autoResolveContentType

          public String autoResolveContentType(String typeName,
                                               String url,
                                               byte[] data)

      A facade interface to trying all the possible mime type resolution strategies available within Tika. First, the mime type provided in `typeName` is cleaned, with `cleanMimeType(String)`. Then the cleaned mime type is looked up in the underlying Tika `MimeTypes` registry, by its cleaned name. If the `MimeType` is found, then that mime type is used, otherwise URL resolution is used to try and determine the mime type. However, if `mime.type.magic` is enabled in `NutchConfiguration`, then mime type magic resolution is used to try and obtain a better-than-the-default approximation of the `MimeType`.
      Parameters:
        `typeName` - The original mime type, returned from a `ProtocolOutput`.
        `url` - The given @see url, that Nutch was trying to crawl.
        `data` - The byte data, returned from the crawl, if any.
      Returns:
        The correctly, automatically guessed `MimeType` name.

    - #### getMimeType

          public String getMimeType(String url)

      Facade interface to Tika's underlying `MimeTypes.getMimeType(String)` method.
      Parameters:
        `url` - A string representation of the document URL to sense the `MimeType` for.
      Returns:
        An appropriate `MimeType`, identified from the given Document url in string form.

    - #### forName

          public String forName(String name)

      A facade interface to Tika's underlying `MimeTypes.forName(String)` method.
      Parameters:
        `name` - The name of a valid `MimeType` in the Tika mime registry.
      Returns:
        The object representation of the `MimeType`, if it exists, or null otherwise.

    - #### getMimeType

          public String getMimeType(File f)

      Facade interface to Tika's underlying `MimeTypes.getMimeType(File)` method.
      Parameters:
        `f` - The `File` to sense the `MimeType` for.
      Returns:
        The `MimeType` of the given `File`, or null if it cannot be determined.

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