ImageServer

java.lang.Object
- ohmm.ImageServer

```
public class ImageServer
extends java.lang.Object
```
HTTP multipart/x-mixed-replace image server.

The source frames are provided via the hook updateImage(java.awt.image.BufferedImage), which also sets the width and height. The compression type, compression quality (if appliccable), and maximum served frames per second are controlled by URL query parameters "fmt" (string, e.g. "jpeg" or "png"), "fps" (float), and "qual" (int, 0=min, 100=max), respectively. They default to defFmt, defFPS, and defQual if the query params are not given.

Key and mouse events are collected from the client and made available in image coordinates via the hooks handleKey(char) and handleMouse(int, int, int, int).

Tested with Chrome and Safari. Firefox might or might not work (Mozilla bug 625012). On any browser, non-alphanumeric keycodes may differ from Java std.

The server knows about the following request paths:
- /server.html (also / and /index.html) - the server page including the image and javascript to send keyboard and mouse events back (accepts the optional "fmt", "fps", and "qual" query params)
- /image - the live image (also accepts the optional "fmt", "fps", and "qual" query params)
- /key - special path to recieve HTML GET requests encoding key events on the client
- /mouse - special path to recieve HTML GET requests encoding mouse events on the client
- /echo - echo the client request for debugging
Once the server is running, you can connect to it from a remote host by bringing up e.g. Google Chrome and browsing to the url
```
 http://ADDR:PORT/server.html

 
```
where ADDR is the IP address and PORT the listening port of the server. You can further control the image format, framerate, and quality like this:
```
 http://ADDR:PORT/server.html?fmt=jpg&fps=10&qual=95

 
```
Author:

Marsette Vona

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

protected class ImageServer.ExchangeState
Wraps an HttpExchange with some derived values.

Nested Classes
Modifier and Type	Class and Description
`protected class`	`ImageServer.ExchangeState` Wraps an HttpExchange with some derived values.

Field Summary

Fields
Modifier and Type	Field and Description
`boolean`	`dbg` Debug next server frame.
`static java.lang.String`	`DEF_FMT` Default `defFmt`.
`static float`	`DEF_FPS` Default `defFPS`.
`static int`	`DEF_PORT` Default TCP listen port.
`static int`	`DEF_QUAL` Default `defQual`.
`static int`	`DEF_STOP_SEC` Default `stop(int)` delay seconds.
`java.lang.String`	`defFmt` Default ImageIO format name.
`float`	`defFPS` Default max framerate.
`int`	`defQual` Default image quality in the range 0 (min) to 100 (max).
`static int`	`EVENT_FLAG_ALTKEY` Event flags for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_FLAG_CTRLKEY` Event flags for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_FLAG_LBUTTON` Event flags for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_FLAG_MBUTTON` Event flags for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_FLAG_RBUTTON` Event flags for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_FLAG_SHIFTKEY` Event flags for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_LBUTTONDBLCLK` Event types for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_LBUTTONDOWN` Event types for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_LBUTTONUP` Event types for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_MBUTTONDBLCLK` Event types for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_MBUTTONDOWN` Event types for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_MBUTTONUP` Event types for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_MOUSEMOVE` Event types for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_RBUTTONDBLCLK` Event types for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_RBUTTONDOWN` Event types for `handleMouse(int, int, int, int)`.
`static int`	`EVENT_RBUTTONUP` Event types for `handleMouse(int, int, int, int)`.
`protected java.util.concurrent.ExecutorService`	`executor` The internal transaction executor.
`static int`	`HTTP_FORBIDDEN` HTTP response codes
`static int`	`HTTP_NOT_FOUND` HTTP response codes
`static int`	`HTTP_OK` HTTP response codes
`protected int`	`imageClients` Number of clients to which we're currently serving images.
`static java.lang.String`	`MIME_BOUNDARY` MIME multipart boundary
`java.io.PrintStream`	`msgStream` Strems for messages and warnings, or null to disable.
`static java.text.DecimalFormat`	`NF` Number format for printouts.
`protected boolean`	`oneClient` Whether to limit serving images to one client.
`int`	`port` Server TCP listen port.
`protected com.sun.net.httpserver.HttpServer`	`server` The internal server object.
`static java.lang.String`	`SERVER_HTML` Server html file.
`boolean`	`spewMouseMoves` Whether to output lots of debug messages for mousemove events.
`boolean`	`spewStackTraces` Whether to dump stack traces on server errors.
`java.io.PrintStream`	`warnStream` Strems for messages and warnings, or null to disable.

Constructor Summary

Constructors
Constructor and Description

ImageServer()
Creates server using DEF_PORT.

ImageServer(int port)
Creates server.

Constructors
Constructor and Description
`ImageServer()` Creates server using `DEF_PORT`.
`ImageServer(int port)` Creates server.

Method Summary

Methods
Modifier and Type	Method and Description
`protected java.io.InputStream`	`getServerHTML()` Hook to get the html the server sends to the client.
`static java.net.InetAddress[]`	`getServerIPs()` Get the server's non-local IP address(es).
`protected void`	`handleEcho(ImageServer.ExchangeState xs)` Serves debug echo info.
`protected void`	`handleExchange(com.sun.net.httpserver.HttpExchange xch)` Dispatches HTTP exchange to one of the handle*(ExchangeState) methods.
`protected void`	`handleImage(ImageServer.ExchangeState xs)` Serves images.
`protected void`	`handleKey(char c)` Hook to handle key events.
`protected void`	`handleKey(ImageServer.ExchangeState xs)` Handles key event requests.
`protected void`	`handleMouse(ImageServer.ExchangeState xs)` Handles mouse event requests.
`protected void`	`handleMouse(int t, int x, int y, int m)` Hook to handle mouse events.
`protected void`	`handleServer(ImageServer.ExchangeState xs)` Serves `SERVER_HTML` using `getServerHTML()`.
`protected void`	`handleUnknown(ImageServer.ExchangeState xs)` Handles unknown request paths.
`static void`	`main(java.lang.String[] argv)` Starts a test server.
`protected void`	`msg(java.lang.String m)` Display a message to `msgStream`, if any.
`protected static long`	`nowMS()` Returns current time in milliseconds.
`void`	`start()` Starts server.
`void`	`stop()` `stop(int)` delaying `DEF_STOP_SEC`.
`void`	`stop(int delay)` Stops `server` and `executor`.
`protected java.awt.image.BufferedImage`	`updateImage(java.awt.image.BufferedImage bi)` Hook called to update the server image.
`protected void`	`warn(java.lang.String m)` Display a warning to `warnStream`, if any.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - DEF_PORT
```
public static final int DEF_PORT
```
    Default TCP listen port.
    
    See Also:
    Constant Field Values
  - DEF_FMT
```
public static final java.lang.String DEF_FMT
```
    Default defFmt.
    
    See Also:
    Constant Field Values
  - DEF_FPS
```
public static final float DEF_FPS
```
    Default defFPS.
    
    See Also:
    Constant Field Values
  - DEF_QUAL
```
public static final int DEF_QUAL
```
    Default defQual.
    
    See Also:
    Constant Field Values
  - DEF_STOP_SEC
```
public static final int DEF_STOP_SEC
```
    Default stop(int) delay seconds.
    
    See Also:
    Constant Field Values
  - SERVER_HTML
```
public static final java.lang.String SERVER_HTML
```
    Server html file.
    
    See Also:
    Constant Field Values
  - HTTP_OK
```
public static final int HTTP_OK
```
    HTTP response codes
    
    See Also:
    Constant Field Values
  - HTTP_NOT_FOUND
```
public static final int HTTP_NOT_FOUND
```
    HTTP response codes
    
    See Also:
    Constant Field Values
  - HTTP_FORBIDDEN
```
public static final int HTTP_FORBIDDEN
```
    HTTP response codes
    
    See Also:
    Constant Field Values
  - MIME_BOUNDARY
```
public static final java.lang.String MIME_BOUNDARY
```
    MIME multipart boundary
    
    See Also:
    Constant Field Values
  - EVENT_MOUSEMOVE
```
public static final int EVENT_MOUSEMOVE
```
    Event types for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event types.
    
    See Also:
    Constant Field Values
  - EVENT_LBUTTONDOWN
```
public static final int EVENT_LBUTTONDOWN
```
    Event types for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event types.
    
    See Also:
    Constant Field Values
  - EVENT_RBUTTONDOWN
```
public static final int EVENT_RBUTTONDOWN
```
    Event types for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event types.
    
    See Also:
    Constant Field Values
  - EVENT_MBUTTONDOWN
```
public static final int EVENT_MBUTTONDOWN
```
    Event types for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event types.
    
    See Also:
    Constant Field Values
  - EVENT_LBUTTONUP
```
public static final int EVENT_LBUTTONUP
```
    Event types for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event types.
    
    See Also:
    Constant Field Values
  - EVENT_RBUTTONUP
```
public static final int EVENT_RBUTTONUP
```
    Event types for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event types.
    
    See Also:
    Constant Field Values
  - EVENT_MBUTTONUP
```
public static final int EVENT_MBUTTONUP
```
    Event types for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event types.
    
    See Also:
    Constant Field Values
  - EVENT_LBUTTONDBLCLK
```
public static final int EVENT_LBUTTONDBLCLK
```
    Event types for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event types.
    
    See Also:
    Constant Field Values
  - EVENT_RBUTTONDBLCLK
```
public static final int EVENT_RBUTTONDBLCLK
```
    Event types for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event types.
    
    See Also:
    Constant Field Values
  - EVENT_MBUTTONDBLCLK
```
public static final int EVENT_MBUTTONDBLCLK
```
    Event types for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event types.
    
    See Also:
    Constant Field Values
  - EVENT_FLAG_LBUTTON
```
public static final int EVENT_FLAG_LBUTTON
```
    Event flags for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event flags.
    
    See Also:
    Constant Field Values
  - EVENT_FLAG_RBUTTON
```
public static final int EVENT_FLAG_RBUTTON
```
    Event flags for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event flags.
    
    See Also:
    Constant Field Values
  - EVENT_FLAG_MBUTTON
```
public static final int EVENT_FLAG_MBUTTON
```
    Event flags for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event flags.
    
    See Also:
    Constant Field Values
  - EVENT_FLAG_CTRLKEY
```
public static final int EVENT_FLAG_CTRLKEY
```
    Event flags for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event flags.
    
    See Also:
    Constant Field Values
  - EVENT_FLAG_SHIFTKEY
```
public static final int EVENT_FLAG_SHIFTKEY
```
    Event flags for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event flags.
    
    See Also:
    Constant Field Values
  - EVENT_FLAG_ALTKEY
```
public static final int EVENT_FLAG_ALTKEY
```
    Event flags for handleMouse(int, int, int, int).
    
    Compatible with OpenCV event flags.
    
    See Also:
    Constant Field Values
  - NF
```
public static final java.text.DecimalFormat NF
```
    Number format for printouts.
  - port
```
public final int port
```
    Server TCP listen port.
  - defFmt
```
public volatile java.lang.String defFmt
```
    Default ImageIO format name.
  - defFPS
```
public volatile float defFPS
```
    Default max framerate.
  - defQual
```
public volatile int defQual
```
    Default image quality in the range 0 (min) to 100 (max).
  - dbg
```
public volatile boolean dbg
```
    Debug next server frame.
  - msgStream
```
public volatile java.io.PrintStream msgStream
```
    Strems for messages and warnings, or null to disable.
  - warnStream
```
public volatile java.io.PrintStream warnStream
```
    Strems for messages and warnings, or null to disable.
  - spewMouseMoves
```
public volatile boolean spewMouseMoves
```
    Whether to output lots of debug messages for mousemove events.
  - spewStackTraces
```
public volatile boolean spewStackTraces
```
    Whether to dump stack traces on server errors.
  - imageClients
```
protected volatile int imageClients
```
    Number of clients to which we're currently serving images.
  - oneClient
```
protected volatile boolean oneClient
```
    Whether to limit serving images to one client.
  - server
```
protected final com.sun.net.httpserver.HttpServer server
```
    The internal server object.
  - executor
```
protected final java.util.concurrent.ExecutorService executor
```
    The internal transaction executor.
- Constructor Detail
  - ImageServer
```
public ImageServer(int port)
            throws java.io.IOException
```
    Creates server.
    
    You may configure public fields before calling start().
    
    Parameters:
    port - the TCP listen port
    
    Throws:
    
    java.io.IOException
  - ImageServer
```
public ImageServer()
            throws java.io.IOException
```
    Creates server using DEF_PORT.
    
    Throws:
    
    java.io.IOException
- Method Detail
  - handleExchange
```
protected void handleExchange(com.sun.net.httpserver.HttpExchange xch)
                       throws java.io.IOException
```
    Dispatches HTTP exchange to one of the handle*(ExchangeState) methods.
    
    Throws:
    
    java.io.IOException
  - handleEcho
```
protected void handleEcho(ImageServer.ExchangeState xs)
                   throws java.io.IOException
```
    Serves debug echo info.
    
    Throws:
    
    java.io.IOException
  - handleServer
```
protected void handleServer(ImageServer.ExchangeState xs)
                     throws java.io.IOException
```
    Serves SERVER_HTML using getServerHTML().
    
    Throws:
    
    java.io.IOException
  - getServerHTML
```
protected java.io.InputStream getServerHTML()
                                     throws java.io.IOException
```
    Hook to get the html the server sends to the client.
    
    Default impl uses getResourceAsStream() to open and return SERVER_HTML.
    
    Throws:
    
    java.io.IOException
  - handleImage
```
protected void handleImage(ImageServer.ExchangeState xs)
                    throws java.lang.Exception
```
    Serves images.
    
    Throws:
    
    java.lang.Exception
  - updateImage
```
protected java.awt.image.BufferedImage updateImage(java.awt.image.BufferedImage bi)
```
    Hook called to update the server image.
    
    Parameters:
    bi - the prior image, if any, else null
    
    Returns:
    the new image, if any, else null
    Will be called by a server exchange handling thread while synchronized on this ImageServer instance.
    
    Default impl does nothing. Subclasses can override this to provide images. To avoid creating a lot of memory garbage it is recommended to create the image once and then to update it in place on subsequent frames.
  - handleMouse
```
protected void handleMouse(ImageServer.ExchangeState xs)
```
    Handles mouse event requests.
    
    Parses the event parameters and then calls handleMouse(int, int, int, int) which can be overridden as desired.
  - handleMouse
```
protected void handleMouse(int t,
               int x,
               int y,
               int m)
```
    Hook to handle mouse events.
    
    Parameters:
    t - one of the EVENT_* constants
    x - the x pixel coordinate of the mouse event
    y - the y pixel coordinate of the mouse event
    m - bitmask of the EVENT_FLAG_* constants
    This is called when the client notifies the server that a mouse event has occured over the image.
    
    Default impl does nothing. Subclasses can override this to take action on mouse events over the client image.
  - handleKey
```
protected void handleKey(ImageServer.ExchangeState xs)
```
    Handles key event requests.
    
    Parses the event parameters and then calls handleKey(char) which can be overridden as desired.
  - handleKey
```
protected void handleKey(char c)
```
    Hook to handle key events.
    
    Parameters:
    c - the key character
    This is called when the client notifies the server that a key event has occured over the image.
    
    Default impl does nothing. Subclasses can override this to take action on key events over the client image.
  - handleUnknown
```
protected void handleUnknown(ImageServer.ExchangeState xs)
                      throws java.io.IOException
```
    Handles unknown request paths.
    
    Throws:
    
    java.io.IOException
  - nowMS
```
protected static long nowMS()
```
    Returns current time in milliseconds.
  - msg
```
protected void msg(java.lang.String m)
```
    Display a message to msgStream, if any.
  - warn
```
protected void warn(java.lang.String m)
```
    Display a warning to warnStream, if any.
  - start
```
public void start()
           throws java.io.IOException
```
    Starts server.
    
    Throws:
    
    java.io.IOException
  - stop
```
public void stop(int delay)
```
    Stops server and executor.
    
    Parameters:
    delay - seconds to wait for any ongoing exchanges to finish
    Call this to bring the server down.
  - stop
```
public void stop()
```
    stop(int) delaying DEF_STOP_SEC.
  - getServerIPs
```
public static java.net.InetAddress[] getServerIPs()
                                           throws java.io.IOException
```
    Get the server's non-local IP address(es).
    
    Throws:
    
    java.io.IOException
  - main
```
public static void main(java.lang.String[] argv)
                 throws java.io.IOException
```
    Starts a test server.
    
    Parameters:
    argv - up to one arg is accepted giving the TCP listen port
    Serves synthetic images marked with their frame number.
    
    Throws:
    
    java.io.IOException

Class ImageServer

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DEF_PORT

DEF_FMT

DEF_FPS

DEF_QUAL

DEF_STOP_SEC

SERVER_HTML

HTTP_OK

HTTP_NOT_FOUND

HTTP_FORBIDDEN

MIME_BOUNDARY

EVENT_MOUSEMOVE

EVENT_LBUTTONDOWN

EVENT_RBUTTONDOWN

EVENT_MBUTTONDOWN

EVENT_LBUTTONUP

EVENT_RBUTTONUP

EVENT_MBUTTONUP

EVENT_LBUTTONDBLCLK

EVENT_RBUTTONDBLCLK

EVENT_MBUTTONDBLCLK

EVENT_FLAG_LBUTTON

EVENT_FLAG_RBUTTON

EVENT_FLAG_MBUTTON

EVENT_FLAG_CTRLKEY

EVENT_FLAG_SHIFTKEY

EVENT_FLAG_ALTKEY

NF

port

defFmt

defFPS

defQual

dbg

msgStream

warnStream

spewMouseMoves

spewStackTraces

imageClients

oneClient

server

executor

Constructor Detail

ImageServer

ImageServer

Method Detail

handleExchange

handleEcho

handleServer

getServerHTML

handleImage

updateImage

handleMouse

handleMouse

handleKey

handleKey

handleUnknown

nowMS

msg

warn

start

stop

stop

getServerIPs

main