io.milton.resource

Interface GetableResource

All Superinterfaces:

Resource

All Known Subinterfaces:

BufferingControlResource, FileResource, FolderResource, PostableResource

public interface GetableResource
extends Resource

webDAV GET and HEAD

Method Summary

Modifier and Type	Method and Description
Long	getContentLength() The length of the content in this resource.
String	getContentType(String accepts) Given a comma separated listed of preferred content types acceptable for a client, return one content type which is the best.
Long	getMaxAgeSeconds(Auth auth) How many seconds to allow the content to be cached for, or null if caching is not allowed The provided auth object allows this method to determine an appropriate caching time depending on authenticated context.
void	sendContent(OutputStream out, Range range, Map<String,String> params, String contentType) Send the resource's content using the given output stream.

Methods inherited from interface io.milton.resource.Resource

authenticate, authorise, checkRedirect, getModifiedDate, getName, getRealm, getUniqueId

Method Detail

sendContent

void sendContent(OutputStream out,
                 Range range,
                 Map<String,String> params,
                 String contentType)
          throws IOException,
                 io.milton.http.exceptions.NotAuthorizedException,
                 io.milton.http.exceptions.BadRequestException,
                 io.milton.http.exceptions.NotFoundException

Send the resource's content using the given output stream. Implementations should assume that bytes are being physically transmitted and that headers have already been committed, although this might not be the case with all web containers.

This method will be used to serve GET requests, and also to generate content following POST requests (if they have not redirected)

The Range argument is not-null for partial content requests. In this case implementations should (but are not required) to only send the data range requested.

The contentType argument is that which was resolved by negotiation in the getContentType method. HTTP allows a given resource to have multiple representations on the same URL. For example, a data series could be retrieved as a chart as SVG, PNG, JPEG, or as text as CSV or XML. When the user agent requests the resource is specified what content types it can accept. These are matched against those that can be provided by the server and a preferred representation is selected. That contentType is set in the response header and is provided here so that the resource implementation can render itself appropriately.

Parameters:

out - - the output stream to send the content to

range - - null for normal GET's, not null for partial GET's. May be ignored

params - - request parameters

contentType - - the contentType selected by negotiation

Throws:

IOException - - if there is an exception writing content to the output stream. This indicates that the client has disconnected (as frequently occurs with http transfers). DO NOT throw an IOException if there was an internal error generating the response (eg if reading from a database)

com.bradmcevoy.http.exceptions.NotAuthorizedException

io.milton.http.exceptions.NotAuthorizedException

io.milton.http.exceptions.BadRequestException

io.milton.http.exceptions.NotFoundException

getMaxAgeSeconds

Long getMaxAgeSeconds(Auth auth)

How many seconds to allow the content to be cached for, or null if caching is not allowed The provided auth object allows this method to determine an appropriate caching time depending on authenticated context. For example, in a CMS in might be appropriate to have a short expiry time for logged in users who might be editing content, as opposed to non-logged in users who are just viewing the site.

getContentType

String getContentType(String accepts)

Given a comma separated listed of preferred content types acceptable for a client, return one content type which is the best.

Returns the most preferred MIME type. E.g. text/html, image/jpeg, etc

Must be IANA registered

accepts is the accepts header. Eg: Accept: text/*, text/html, text/html;level=1

See - http://www.iana.org/assignments/media-types/ for a list of content types See - http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html for details about the accept header

See here for a fun discussion of using content type and accepts for XHTML - http://stackoverflow.com/questions/348736/is-writing-self-closing-tags-for-elements-not-traditionally-empty-bad-practice

If you can't handle accepts interpretation, just return a single content type - E.g. text/html

But typically you should do something like this:

   String mime = ContentTypeUtils.findContentTypes( this.file );
   return ContentTypeUtils.findAcceptableContentType( mime, preferredList );
 

See Also:

com.bradmcevoy.common.ContentTypeUtils

getContentLength

Long getContentLength()

The length of the content in this resource. If unknown return NULL