sunlabs.brazil.server
Class FileHandler

java.lang.Object
  sunlabs.brazil.server.FileHandler (view source)

All Implemented Interfaces:

Handler

public class FileHandler
extends Object
implements Handler

Standard handler for fetching static files. This handler does URL to file conversion, file suffix to mime type lookup, delivery of index files where providing directory references, and redirection for missing slashes (/) at the end of directory requests.

The following configuration parameters are used:

root

property for document root (.) Since the document root is common to many handlers, if no root property is found with the supplied prefix, then the root property with the empty prefix ("") is used instead. This allows many handlers to share the common property.

default

The document to deliver if the URL ends in "/". (defaults to index.html.)

prefix

Only url's that start with this are allowed. defaults to "". The prefix is removed from the url before looking it up in the file system. So, if prefix is /foo then the the file [root]/foo/bar.html will be delivered in response to the url /bar.html.

mime

property for mime type For each file suffix .XX, the property mime.XX is used to determine the mime type. If no property exists (or its value is "unknown", the document will not be delivered.

mimePatterns

List of glob patterns that match file name suffixes for matching mime types. For example:

                mimePatterns=.x* .a?
                mime.x*=text/xml
                mime.a?=application/octet-stream
                

The types corrosponding to mime patterns are searched for in mimePattern order, first looking for prefix.mime.pattern then mime.pattern. If neither property exists, then the type is invalid.

getOnly

If defined, only "GET" requests will be processed. By default, all request types are handled. (Note: this is the inverse of the previous policy, defined by the undocumented "allow" parameter).

strictTypes

If defined, only mime types specifically listed with The file handlers prefix will be delivered.

The FileHandler sets the following entries in the request properties as a side-effect:

fileName

The absolute path of the file that couldn't be found.

DirectoryName

If the URL specified is a directory name, its absolute path is placed here.

lastModified

The Time stamp of the last modified time

This handler supports a subset of the http range header of the form range bytes=[start]-[end], where start and end are byte positions in the file, starting at zero. A large or missing end value is treated as the end of the file. If a valid rangeheader is found, the appropriate content-range header is returned, along with the partial contents of the file.

Field Summary

static String	MIME
static String	ROOT
static String	UNKNOWN
String	urlPrefix

Constructor Summary

FileHandler()

Method Summary

static String	getMimeType(String name, Properties props, String prefix) Get the mime type based on the suffix of a String.
static String	getMimeType(String name, Properties props, String prefix, boolean strict) If "strict" is set, only return types that specifically match properties with this handlers prefix.
boolean	init(Server server, String prefix) Initialize the file handler.
boolean	respond(Request request) Find, read, and deliver via http the requested file.
static void	sendFile(Request request, File file, int code, String type) Send a file as a response.
static void	setModified(Properties props, long mod) Set the "lastModified" request property.
static String	urlToPath(String url) Helper function to convert an url into a pathname.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MIME

public static final String MIME

See Also:

Constant Field Values

UNKNOWN

public static final String UNKNOWN

See Also:

Constant Field Values

ROOT

public static final String ROOT

See Also:

Constant Field Values

urlPrefix

public String urlPrefix

Constructor Detail

FileHandler

public FileHandler()

Method Detail

init

public boolean init(Server server,
                    String prefix)

Initialize the file handler.

Specified by:

init in interface Handler

Parameters:

server - The HTTP server that created this Handler. Typical Handlers will use Server.props to obtain run-time configuration information.

prefix - The handlers name. The string this Handler may prepend to all of the keys that it uses to extract configuration information from Server.props. This is set (by the Server and ChainHandler) to help avoid configuration parameter namespace collisions.

Returns:

The file handler always returns true.

respond

public boolean respond(Request request)
                throws IOException

Find, read, and deliver via http the requested file. The server property root is used as the document root. The document root is recalculated for each request, so an upstream handler may change it for that request. For URL's ending with "/", the server property default (normally index.html) is automatically appended. If the file suffix is not found as a server property mime.suffix, the file is not delivered.

Specified by:

respond in interface Handler

Parameters:

request - The Request object that represents the HTTP request.

Returns:

true if the request was handled. A request was handled if a response was supplied to the client, typically by calling Request.sendResponse() or Request.sendError.

Throws:

IOException - if there was an I/O error while sending the response to the client. Typically, in that case, the Server will (try to) send an error message to the client and then close the client's connection.

The IOException should not be used to silently ignore problems such as being unable to access some server-side resource (for example getting a FileNotFoundException due to not being able to open a file). In that case, the Handler's duty is to turn that IOException into a HTTP response indicating, in this case, that a file could not be found.

getMimeType

public static String getMimeType(String name,
                                 Properties props,
                                 String prefix)

Get the mime type based on the suffix of a String. The suffix (e.g. text after the last ".") is used to lookup the entry "prefix.mime.[suffix]" then "mime.[suffix]" in props. If neither entry is found, then mime glob pattern are used, if available. If there is no suffix, then the empty string is used.

If the mime type is set to the special string "unknown", then the type is unknown. This allows specific types to be undefined when glob patterns are used.

If the property "prefix.mimePatterns" (or "mimePatterns") exists, then it specifies a white-space delimited set of glob style patterns for matching file suffixes to types. If a match for a specific file suffix fails, then the property "mime.[pattern]" is used for type comparisons.

The entries:

 mimePatterns=*ml
 mime.*ml=text/xml
 

would associate the type "text/xml" with the file foo.html, foo.xml and foo.dhtml. The entries:

 mimePatterns=*
 mime*=application/octet-stream
 mime.config=unknown
 

Would set the types for all file types not otherwise defined to be "application/octet-stream", except that files ending in ".config" would have no type (e.g. they would generate a file not found error).

Parameters:

name - The string to compute the mime type for

props - The properties to look up the mime types in.

prefix - The properties prefix for the name lookup

Returns:

The type (or null if not found).

getMimeType

public static String getMimeType(String name,
                                 Properties props,
                                 String prefix,
                                 boolean strict)

If "strict" is set, only return types that specifically match properties with this handlers prefix.

urlToPath

public static String urlToPath(String url)

Helper function to convert an url into a pathname.

• Collapse all %XX sequences.
• Ignore missing initial "/".
• Collapse all "/..", "/.", and "//" sequences.

URL(String) collapses all "/.." (and "/.") sequences, except for a trailing "/.." (or "/."), which would lead to the possibility of escaping from the document root.

File.getPath in jdk-1.1 leaves all the "//" constructs in, but it collapses them in jdk-1.2, so we have to always take it out ourselves, just to be sure.

Parameters:

url - The file path from the URL (that is, minus the "http://host" part). May be null.

Returns:

The path that corresponds to the URL. The returned value begins with "/". The caller can concatenate this path onto the end of some document root.

sendFile

public static void sendFile(Request request,
                            File file,
                            int code,
                            String type)
                     throws IOException

Send a file as a response.

Parameters:

request - The request object

file - The file to output

code - The HTTP status code.

type - The mime type of the file

Throws:

IOException

setModified

public static void setModified(Properties props,
                               long mod)

Set the "lastModified" request property. If already set, use the most recent value.

Parameters:

props - Where to find the "lastModified" property

mod - The modidied time, in ms since the epoch