Examples with StringChunk org.apache.poi.hsmf.datatypes.StringChunk used on opensource projects

Example 6 with StringChunk

use of org.apache.poi.hsmf.datatypes.StringChunk in project tika by apache.

the class OutlookExtractor method guess7BitEncoding.

/**
     * Tries to identify the correct encoding for 7-bit (non-unicode)
     *  strings in the file.
     * <p>Many messages store their strings as unicode, which is
     *  nice and easy. Some use one-byte encodings for their
     *  strings, but don't always store the encoding anywhere
     *  helpful in the file.</p>
     * <p>This method checks for codepage properties, and failing that
     *  looks at the headers for the message, and uses these to
     *  guess the correct encoding for your file.</p>
     * <p>Bug #49441 has more on why this is needed</p>
     * <p>This is taken verbatim from POI (TIKA-1238)
     * as a temporary workaround to prevent unsupported encoding exceptions</p>
     */
private void guess7BitEncoding(MAPIMessage msg) {
    Chunks mainChunks = msg.getMainChunks();
    //sanity check
    if (mainChunks == null) {
        return;
    }
    Map<MAPIProperty, List<PropertyValue>> props = mainChunks.getProperties();
    if (props != null) {
        // First choice is a codepage property
        for (MAPIProperty prop : new MAPIProperty[] { MAPIProperty.MESSAGE_CODEPAGE, MAPIProperty.INTERNET_CPID }) {
            List<PropertyValue> val = props.get(prop);
            if (val != null && val.size() > 0) {
                int codepage = ((PropertyValue.LongPropertyValue) val.get(0)).getValue();
                String encoding = null;
                try {
                    encoding = CodePageUtil.codepageToEncoding(codepage, true);
                } catch (UnsupportedEncodingException e) {
                //swallow
                }
                if (tryToSet7BitEncoding(msg, encoding)) {
                    return;
                }
            }
        }
    }
    // Second choice is a charset on a content type header
    try {
        String[] headers = msg.getHeaders();
        if (headers != null && headers.length > 0) {
            // Look for a content type with a charset
            Pattern p = Pattern.compile("Content-Type:.*?charset=[\"']?([^;'\"]+)[\"']?", Pattern.CASE_INSENSITIVE);
            for (String header : headers) {
                if (header.startsWith("Content-Type")) {
                    Matcher m = p.matcher(header);
                    if (m.matches()) {
                        // Found it! Tell all the string chunks
                        String charset = m.group(1);
                        if (tryToSet7BitEncoding(msg, charset)) {
                            return;
                        }
                    }
                }
            }
        }
    } catch (ChunkNotFoundException e) {
    }
    // meta header if there is no other information?
    try {
        String html = msg.getHtmlBody();
        if (html != null && html.length() > 0) {
            Charset charset = null;
            try {
                charset = detector.detect(new ByteArrayInputStream(html.getBytes(UTF_8)), EMPTY_METADATA);
            } catch (IOException e) {
            //swallow
            }
            if (charset != null && tryToSet7BitEncoding(msg, charset.name())) {
                return;
            }
        }
    } catch (ChunkNotFoundException e) {
    }
    //absolute last resort, try charset detector
    StringChunk text = mainChunks.getTextBodyChunk();
    if (text != null) {
        CharsetDetector detector = new CharsetDetector();
        detector.setText(text.getRawValue());
        CharsetMatch match = detector.detect();
        if (match != null && match.getConfidence() > 35 && tryToSet7BitEncoding(msg, match.getName())) {
            return;
        }
    }
}