sunlabs.brazil.handler
Class LogHandler

java.lang.Object
  sunlabs.brazil.handler.LogHandler (view source)

All Implemented Interfaces:

Handler

public class LogHandler
extends Object
implements Handler

Handler for logging information about requests. Wraps another handler, and logs information about each HTTP request to a file.

Request properties:

handler

The name of the handler to wrap. This can either be the token for the class, or the class name itself.

logFile

The name of the file to log the output to. If the file already exists, data is appended to it. If the file is removed, a new one is created. If no name is specified, one is invented that contains the name and port of the server. Unless an absolute path is specified, the log file is placed in the current directory.

flush

The number of lines of logging output that may be buffered in memory before being written out to the log file. default to 25.

format

The format of the output string. Embedded strings of the form "%X" are replaced, based on the following values for "X":

• %
  A single "%"
• b
  Bytes written to the client for this request.
• d
  Time to service this request (ms).
• i
  Client ip address.
• m
  Request method (GET, POST, etc)
• M
  Memory utilization (%).
• q
  query string (if any)
• r
  Requests used for this connection.
• s
  HTTP result code.
• t
  TimeStamp (ms since epoch).
• T
  Number of active threads.
• u
  URL for this request.
• v
  HTTP protocol version (10 or 11).

Defaults to "%u;%t:%d:%b".

props

If specified This string is tacked onto the end of the "format" string. Entries in the Request Properties may be included using ${...} substitutions.

headers

If specified This string is tacked onto the end of the "props" string. Entries in the HTTPrequest headers may be included using ${...} substitutions.

title

if present, this is output as the first line of the file

See the ChainSawHandler for generating standard format log files.

Field Summary

File	file
int	flush
String	format
Handler	handler
String	headers
String	props
String	title

Constructor Summary

LogHandler()

Method Summary

boolean	init(Server server, String prefix) Initializes the handler.
boolean	respond(Request request) Dispatch the request to the handler.
static String	subst(Request request, String format, long duration) Format a string.

Methods inherited from class java.lang.Object

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

Field Detail

handler

public Handler handler

props

public String props

headers

public String headers

format

public String format

title

public String title

flush

public int flush

file

public File file

Constructor Detail

LogHandler

public LogHandler()

Method Detail

init

public boolean init(Server server,
                    String prefix)

Description copied from interface: Handler

Initializes the 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:

true if this Handler initialized successfully, false otherwise. If false is returned, this Handler should not be used.

respond

public boolean respond(Request request)
                throws IOException

Dispatch the request to the handler. Log information if dispatched handler returns true.

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.

subst

public static String subst(Request request,
                           String format,
                           long duration)

Format a string. Replace %X constructs.