/**
* Respond to a range request, either with the requested bytes, or with a {@code 416 REQUESTED
* RANGE NOT SATISFIABLE} response if the requested byte range falls outside the length of the
* attachment. If the range request header is syntactically invalid, nothing is written, and
* instead {@code false} is returned, letting the action handler ignore the Range header and treat
* this as a normal (full) download request.
*
* @param attachment the attachment to get content from
* @param request the current client request
* @param response the response to write to.
* @param context the current request context
* @return {@code true} if the partial content request was syntactically valid and a response was
* sent, {@code false} otherwise
* @throws XWikiException if the attachment content cannot be retrieved
* @throws IOException if the response cannot be written
*/
private static boolean sendPartialContent(
final XWikiAttachment attachment,
final XWikiRequest request,
final XWikiResponse response,
final XWikiContext context)
throws XWikiException, IOException {
String range = request.getHeader(RANGE_HEADER_NAME);
Matcher m = RANGE_HEADER_PATTERN.matcher(range);
if (m.matches()) {
String startStr = m.group(1);
String endStr = m.group(2);
Long start = NumberUtils.createLong(startStr);
Long end = NumberUtils.createLong(endStr);
if (start == null && end != null && end > 0) {
// Tail request, output the last <end> bytes
start = Math.max(attachment.getContentSize(context) - end, 0L);
end = attachment.getContentSize(context) - 1L;
}
if (!isValidRange(start, end)) {
return false;
}
if (end == null) {
end = attachment.getContentSize(context) - 1L;
}
end = Math.min(end, attachment.getContentSize(context) - 1L);
writeByteRange(attachment, start, end, request, response, context);
return true;
}
return false;
}
@Override
public String render(XWikiContext context) throws XWikiException {
XWikiRequest request = context.getRequest();
XWikiResponse response = context.getResponse();
XWikiDocument doc = context.getDoc();
String path = request.getRequestURI();
String filename = Util.decodeURI(getFileName(path, ACTION_NAME), context);
XWikiAttachment attachment = null;
final String idStr = request.getParameter("id");
if (StringUtils.isNumeric(idStr)) {
int id = Integer.parseInt(idStr);
if (doc.getAttachmentList().size() > id) {
attachment = doc.getAttachmentList().get(id);
}
} else {
attachment = doc.getAttachment(filename);
}
if (attachment == null) {
Object[] args = {filename};
throw new XWikiException(
XWikiException.MODULE_XWIKI_APP,
XWikiException.ERROR_XWIKI_APP_ATTACHMENT_NOT_FOUND,
"Attachment {0} not found",
null,
args);
}
XWikiPluginManager plugins = context.getWiki().getPluginManager();
attachment = plugins.downloadAttachment(attachment, context);
// Try to load the attachment content just to make sure that the attachment really exists
// This will throw an exception if the attachment content isn't available
try {
attachment.getContentSize(context);
} catch (XWikiException e) {
Object[] args = {filename};
throw new XWikiException(
XWikiException.MODULE_XWIKI_APP,
XWikiException.ERROR_XWIKI_APP_ATTACHMENT_NOT_FOUND,
"Attachment content {0} not found",
null,
args);
}
long lastModifiedOnClient = request.getDateHeader("If-Modified-Since");
long lastModifiedOnServer = attachment.getDate().getTime();
if (lastModifiedOnClient != -1 && lastModifiedOnClient >= lastModifiedOnServer) {
response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
return null;
}
// Sending the content of the attachment
if (request.getHeader(RANGE_HEADER_NAME) != null) {
try {
if (sendPartialContent(attachment, request, response, context)) {
return null;
}
} catch (IOException ex) {
// Broken response...
}
}
sendContent(attachment, request, response, filename, context);
return null;
}