Class MultiHostHandler
- All Implemented Interfaces:
Handler
- Direct Known Subclasses:
RestartingMultiHostHandler
MultiHostHandler
allows the user to handle a set
of host names that are all running on the same IP address. This
handler looks at the http "Host" header and redispatches the request to the
appropriate sub-server.
Only the main server is actually listening to the port on the specified IP address. The sub-servers are not running in separate threads. Indeed, they are not "running" at all. They exist merely as a convenient bag to hold each of the server-specific configuration parameters.
The respond
method of the main handler for the appropriate
sub-server is called directly from the respond
method of
this handler.
This handler uses the following configuration parameters:
- servers
- The list of prefixes for the other servers. Each server will be
initialized from the main
server.props
with the specified prefix. In this way, the configuration parameters for all the sub-servers can be stored in the sameProperties
object. - prefix.host
- Each server is started with a given prefix. The property prefix.host specifies a Glob pattern for a virtual hostname the server will be expected to handle. If this property is not specified, the server's virtual hostname will just be prefix. If multiple host patterns could match a given "Host" header, the first match in the "servers" list matches first.
- prefix.handler
- The main handler for the server with the given prefix. If
this property is not specified, it defaults to the
FileHandler
. - prefix.config
- Read in the file specified by "config" to initialize this sub-server's
server properties. The file is expected to be in java properties
format. If not specified, this sub-server shares a copy
of the main server's properties, otherwise, the main server's properties
are used as the "default". If this property is specified and no
config file is found, then the sub-server isn't started.
The property "root", if included in the "config" file, is treated specially: If it does not represent an absolute path, then it is resolved relative to the main server's root.
handler=host port=8081 log=5 host.class=sunlabs.brazil.server.MultiHostHandler host.servers=mars jupiter saturn mars.host=www.mars.com mars.log=2 mars.handler=mars.file mars.file.class=sunlabs.brazil.server.FileHandler mars.file.root=public_html/mars jupiter.host=jupiter.planet.org jupiter.handler=sunlabs.brazil.server.FileHandler jupiter.root=public_html/jupiter saturn.host=*.saturn.planet.org saturn.handler=sunlabs.brazil.server.FileHandler saturn.root=public_html/saturnThese parameters set up a normal
Server
on port 8081,
running a MultiHostHandler
. The MultiHostHandler
will create three additional servers that respond to the virtual hosts
"www.mars.com", "jupiter.planet.org", and "Server.prefix
of "mars",
so that all other configuration parameters that the "mars" server
examines can begin with "mars" and be kept distinct from the "jupiter"
and "saturn" parameters.
The main server and the three sub-servers will all share the same properties object, but can use their own individual prefixes to keep their data separate (because "inherit" is not set).
- Version:
- 2.6, 07/01/29
- Author:
- Colin Stevens (colin.stevens@sun.com)
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionboolean
Initializes the servers for the virtual hosts.boolean
Responds to an HTTP request by examining the "Host:" request header and dispatching to the main handler of the server that handles that virtual host.
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Constructor Details
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MultiHostHandler
public MultiHostHandler()
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Method Details
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init
Initializes the servers for the virtual hosts. After creating and initializing each sub-server, theinit
method of the main handler for each sub-server is called.- Specified by:
init
in interfaceHandler
- Parameters:
server
- The HTTP server that created this handler.prefix
- A prefix to prepend to all of the keys that this handler uses to extract configuration information.- Returns:
true
if at least one sub-server was found and could be initialized,false
otherwise. Diagnostic messages are logged for each sub-server started.
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respond
Responds to an HTTP request by examining the "Host:" request header and dispatching to the main handler of the server that handles that virtual host. If the "Host:" request header was not specified, or named a virtual host that was not initialized ininit
from the list of virtual hosts, this method returns without handling the request. Port numbers are not used for host matching.- Specified by:
respond
in interfaceHandler
- Parameters:
request
- The HTTP request to be forwarded to one of the sub-servers.- Returns:
true
if the sub-server handled the message,false
if it did not.false
is also returned if the "Host:" was unspecified or unknown.- Throws:
IOException
- if there was an I/O error while sending the response to the client. Typically, in that case, theServer
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 aFileNotFoundException
due to not being able to open a file). In that case, theHandler
's duty is to turn thatIOException
into a HTTP response indicating, in this case, that a file could not be found.
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