Class WEnvironment

java.lang.Object
eu.webtoolkit.jwt.WEnvironment
Direct Known Subclasses:
WTestEnvironment

public class WEnvironment
extends java.lang.Object
A class that captures information on the application environment.

The environment provides information on the client, and gives access to startup arguments.

Usage example:


 WEnvironment env = WApplication.instance().environment();

 // read an application startup argument
 // (passed as argument in the URL or POST'ed to the application).
 if (!env.getParameterValues("login").isEmpty()) {
 String login = env.getParameterValues("login").get(0);
 //...
 }

 // Check for JavaScript/AJAX availability before using JavaScript-only
 // widgets
 WTextArea textEdit;
 if (!env.isAjax())
 textEdit = new WTextEdit(); // provide an HTML text editor
 else
 textEdit = new WTextArea(); // fall-back to a plain old text area.

 
  • Nested Class Summary

    Nested Classes 
    Modifier and Type Class Description
    static class  WEnvironment.ContentType
    Enumeration for HTML content type.
    static class  WEnvironment.UserAgent
    An enumeration type for specific user agent.
  • Field Summary

    Fields 
    Modifier and Type Field Description
    protected java.lang.String timeZoneName_  
  • Method Summary

    Modifier and Type Method Description
    boolean agentIsChrome()
    Returns whether the user agent is Chrome.
    boolean agentIsGecko()
    Returns whether the user agent is Gecko-based.
    boolean agentIsIE()
    Returns whether the user agent is Microsoft Internet Explorer.
    boolean agentIsIElt​(int version)
    Returns whether the user agent is an older version of IE.
    boolean agentIsIEMobile()
    Returns whether the user agent is Internet Explorer Mobile.
    boolean agentIsMobileWebKit()
    Returns whether the user agent is Mobile WebKit-based.
    boolean agentIsOpera()
    Returns whether the user agent is Opera.
    boolean agentIsSafari()
    Returns whether the user agent is Safari.
    boolean agentIsSpiderBot()
    Returns if the user agent is a (known) indexing spider bot.
    boolean agentIsWebKit()
    Returns whether the user agent is WebKit-based.
    java.lang.String getAccept()
    Returns the accept header.
    WEnvironment.UserAgent getAgent()
    Returns the user agent type.
    java.lang.String getCgiValue​(java.lang.String varName)
    Returns a raw CGI environment variable.
    java.lang.String getClientAddress()
    Returns the IP address of the client.
    WEnvironment.ContentType getContentType()
    The type of the content provided to the browser.
    java.lang.String getCookie​(java.lang.String cookieName)
    Returns a cookie value.
    java.util.Map<java.lang.String,​java.lang.String> getCookies()
    Returns the cookies from the environment.
    java.lang.String getCookieValue​(java.lang.String cookieName)
    Returns a cookie value.
    java.lang.String getDeploymentPath()
    Returns the deployment path.
    double getDpiScale()
    Returns the browser-side DPI scaling factor.
    java.lang.String getHeaderValue​(java.lang.String name)
    Returns a header value.
    java.lang.String getHostName()
    Returns the server host name that is used by the client.
    java.lang.String getInternalPath()
    Returns the initial internal path.
    static java.lang.String getJavaScriptWtScope()
    Wt's JavaScript scope.
    static java.lang.String getLibraryVersion()
    Returns the version of the JWt library.
    java.util.Locale getLocale()
    Returns the preferred language indicated in the request header.
    java.lang.String getParameter​(java.lang.String name)
    Returns a single value for a query parameter.
    java.util.Map<java.lang.String,​java.lang.String[]> getParameterMap()
    Parameters passed to the application.
    java.lang.String[] getParameterValues​(java.lang.String name)
    Returns values for a query parameter.
    java.lang.String getReferer()
    Returns the referer.
    int getScreenHeight()
    Returns the vertical resolution of the client's screen.
    int getScreenWidth()
    Returns the horizontal resolution of the client's screen.
    WtServlet getServer()
    Returns the servlet.
    java.lang.String getServerAdmin()
    Returns the email address of the server admin.
    java.lang.String getServerSignature()
    Returns the web server signature.
    java.lang.String getServerSoftware()
    Returns the web server software.
    java.lang.String getSessionId()
    Deprecated.
    java.lang.String getTimeZoneName()
    Returns the time zone name as reported by the client.
    int getTimeZoneOffset()
    Returns the time zone offset as reported by the client.
    java.lang.String getUrlScheme()
    Returns the URL scheme used for the current request ("http" or "https").
    java.lang.String getUserAgent()
    Returns the user agent.
    boolean hasAjax()
    Returns whether the browser has enabled support for AJAX.
    boolean hasJavaScript()
    Returns whether the browser has enabled support for JavaScript.
    boolean hasWebGL()
    Returns whether the browser has support for WebGL.
    boolean isInternalPathUsingFragments()
    Returns whether internal paths are implemented using URI fragments.
    boolean isTest()
    Returns whether this is a mocked test environment.
    boolean supportsCookies()
    Returns whether the browser has enabled support for cookies.
    boolean supportsCss3Animations()
    Returns whether this agent supports CSS3 animations.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

  • Method Details

    • getJavaScriptWtScope

      public static java.lang.String getJavaScriptWtScope()
      Wt's JavaScript scope.
    • getParameterMap

      public java.util.Map<java.lang.String,​java.lang.String[]> getParameterMap()
      Parameters passed to the application.

      Arguments passed to the application, either in the URL for a http GET, or in both the URL and data submitted in a http POST.

      See Also:
      getParameterValues(String name)
    • getParameterValues

      public java.lang.String[] getParameterValues​(java.lang.String name)
      Returns values for a query parameter.

      Returns an empty list if the parameter was not defined.

      One or more values may be associated with a single argument.

      For example a JWt application foo.wt started as http://.../foo.wt?hello=Hello&hello=World will result in both values "Hello" and "World" to be associated with the argument "hello".

      See Also:
      getParameterMap()
    • getParameter

      public java.lang.String getParameter​(java.lang.String name)
      Returns a single value for a query parameter.

      Returns the first value for a parameter, or null if the parameter is not found.

      See Also:
      getParameterValues(String name)
    • getCookies

      public java.util.Map<java.lang.String,​java.lang.String> getCookies()
      Returns the cookies from the environment.

      This returns all cookies that were present in initial request for the application. Cookies set with WApplication#setCookie() are not taken into consideration.

      Cookies allow you to persist information across sessions, but note that not all clients may support cookies or may some clients may be configured to block cookies.

      See Also:
      supportsCookies(), getCookie(String cookieName), getCookieValue(String cookieName)
    • getCookie

      public java.lang.String getCookie​(java.lang.String cookieName)
      Returns a cookie value.

      Throws a RuntimeException("Missing cookie: ...") when the cookie is missing, or returns cookie value otherwise.

      See Also:
      getCookieValue(String cookieName)
    • getCookieValue

      public java.lang.String getCookieValue​(java.lang.String cookieName)
      Returns a cookie value.

      Returns 0 if no value was set for the given cookie.

      See Also:
      getCookie(String cookieName)
    • getHeaderValue

      public java.lang.String getHeaderValue​(java.lang.String name)
      Returns a header value.

      Returns a header value, or an empty string if the header was present.

      Note: Currently, the header name is case sensitive, although this should not be the case according to RFC2616

    • supportsCookies

      public boolean supportsCookies()
      Returns whether the browser has enabled support for cookies.

      When the user disables cookies during the visit of the page, this value is not updated.

      See Also:
      getCookies(), getCookie(String cookieName)
    • hasJavaScript

      public boolean hasJavaScript()
      Returns whether the browser has enabled support for JavaScript.

      This is the same as hasAjax(): JWt only considers using JavaScript when it has detected AJAX support.

      See Also:
      hasAjax()
    • hasAjax

      public boolean hasAjax()
      Returns whether the browser has enabled support for AJAX.

      Without support for JavaScript/AJAX, JWt will still be able to serve the application, but with one considerable limitation: only the WTimer.timeout(), WInteractWidget.clicked(), WApplication.internalPathChanged(), and WAbstractArea.clicked() signals (and any derived signals) will generate events.

      Every event will cause the complete page to be rerendered.

      See Also:
      hasJavaScript()
    • hasWebGL

      public boolean hasWebGL()
      Returns whether the browser has support for WebGL.

      Support for WebGL is required for client-side rendering of WGLWidget.

    • getScreenWidth

      public int getScreenWidth()
      Returns the horizontal resolution of the client's screen.

      Returns -1 if screen width is not known.

      See Also:
      getScreenHeight()
    • getScreenHeight

      public int getScreenHeight()
      Returns the vertical resolution of the client's screen.

      Returns -1 if screen height is not known.

      See Also:
      getScreenWidth()
    • getDpiScale

      public double getDpiScale()
      Returns the browser-side DPI scaling factor.

      Internet Explorer scales all graphics, fonts and other elements on high-density screens to make them readable. This is controlled by the DPI setting of the display. If all goes well, you do not have to worry about this scaling factor. Unfortunately, not all elements are scaled appropriately. The scaling factor is supposed to be used only internally in JWt and is in this interface for informational purposes.

      See Also:
      WVmlImage
    • getLocale

      public java.util.Locale getLocale()
      Returns the preferred language indicated in the request header.

      The language is parsed from the HTTP Accept-Language field, if present. If not, the locale is empty.

      If multiple languages are present, the one with the highest "q"uality is assumed, and if a tie is present, the first one is taken.

      See Also:
      WApplication.setLocale(Locale locale)
    • getTimeZoneOffset

      public int getTimeZoneOffset()
      Returns the time zone offset as reported by the client.

      This returns the time offset that the client has relative to UTC. A positive value thus means that the local time is ahead of UTC.

      This requires JavaScript support.

    • getTimeZoneName

      public java.lang.String getTimeZoneName()
      Returns the time zone name as reported by the client.

      Note: This requires JavaScript support and is only supported by browsers that implement the JavaScript Internationalization API. No version of Internet Explorer supports this, but modern browsers do. If not supported, this will return the empty string.

    • getHostName

      public java.lang.String getHostName()
      Returns the server host name that is used by the client.

      The hostname is the unresolved host name with optional port number, which the browser used to connect to the application.

      Examples:

      • www.mydomain.com
      • localhost:8080

      For HTTP 1.1 requests, this information is fetched from the HTTP Host header. If JWt is configured behind a reverse proxy, then the last entry in the HTTP X-Forwarded-Host header field is used instead (to infer the name of the reverse proxy instead).

      For HTTP 1.0 requests, the HTTP Host header is not required. When not present, the server host name is inferred from the configured server name, which defaults to the DNS name.

    • getUrlScheme

      public java.lang.String getUrlScheme()
      Returns the URL scheme used for the current request ("http" or "https").
    • getUserAgent

      public java.lang.String getUserAgent()
      Returns the user agent.

      The user agent, as reported in the HTTP User-Agent field.

      See Also:
      getAgent()
    • getReferer

      public java.lang.String getReferer()
      Returns the referer.

      The referer, as reported in the HTTP Referer field.

    • getAccept

      public java.lang.String getAccept()
      Returns the accept header.

      The accept header, as reported in the HTTP Accept field.

    • agentIsSpiderBot

      public boolean agentIsSpiderBot()
      Returns if the user agent is a (known) indexing spider bot.

      Note: currently the list of know bots is quite small. This method is used internally to render the web application for optimal indexing by bots:

      • there is no detection for JavaScript, instead the application is directly served assuming no JavaScript support.
      • session information is omitted from the Urls.
      • no sessions are created (they are immediately stopped after the request has been handled).
      • auto-generated id and name attributes are omitted from DOM nodes. In this way, the generated page is always exactly the same.
    • getServerSignature

      public java.lang.String getServerSignature()
      Returns the web server signature.

      The value of the CGI variable SERVER_SIGNATURE.

      Example: <address>Apache Server at localhost Port 80</address>.

    • getServerSoftware

      public java.lang.String getServerSoftware()
      Returns the web server software.

      The value of the CGI variable SERVER_SOFTWARE.

      Example: "Apache"

    • getServerAdmin

      public java.lang.String getServerAdmin()
      Returns the email address of the server admin.

      The value of the CGI variable SERVER_ADMIN.

      Example: "root@localhost"

    • getClientAddress

      public java.lang.String getClientAddress()
      Returns the IP address of the client.

      The (most likely) IP address of the client that is connected to this session.

      This is taken to be the first public address that is given in the Client-IP header, or in the X-Forwarded-For header (in case the client is behind a proxy). If none of these headers is present, the remote socket IP address is used.

    • getInternalPath

      public java.lang.String getInternalPath()
      Returns the initial internal path.

      This is the internal path with which the application was started.

      For an application deployed at "/stuff/app.wt", the following two URLs are considered equivalent, and indicate an internal path "/this/there" :

      
       http://www.mydomain.com/stuff/app.wt/this/there
       http://www.mydomain.com/stuff/app.wt/this/there
      
       

      See Also:
      WApplication.setInternalPath(String path, boolean emitChange), getDeploymentPath()
    • getDeploymentPath

      public java.lang.String getDeploymentPath()
      Returns the deployment path.

      This is the path at which the application is deployed.

      See Also:
      getInternalPath()
    • getLibraryVersion

      public static java.lang.String getLibraryVersion()
      Returns the version of the JWt library.

      Example: "1.99.2"

    • getSessionId

      public java.lang.String getSessionId()
      Deprecated.
      Returns the JWt session id (deprecated).

      Retrieves the session id for this session. This is an auto-generated random alpha-numerical id, whose length is determined by settings in the configuration file.

    • getCgiValue

      public java.lang.String getCgiValue​(java.lang.String varName)
      Returns a raw CGI environment variable.

      Retrieves the value for the given CGI environment variable (like "SSL_CLIENT_S_DN_CN"), if it is defined, otherwise an empty string.

      See Also:
      getServerSignature(), getServerSoftware(), getServerAdmin()
    • getContentType

      public WEnvironment.ContentType getContentType()
      The type of the content provided to the browser.

      This is here for backwards compatibility, but the implementation now alwasy returns HTML5.

    • getAgent

      public WEnvironment.UserAgent getAgent()
      Returns the user agent type.

      This returns an interpretation of the getUserAgent(). It should be used only for user-agent specific work-arounds (as a last resort).

      See Also:
      agentIsIE(), agentIsOpera(), agentIsGecko(), agentIsChrome(), agentIsSafari(), agentIsWebKit()
    • agentIsIE

      public boolean agentIsIE()
      Returns whether the user agent is Microsoft Internet Explorer.

      See Also:
      getAgent()
    • agentIsIElt

      public boolean agentIsIElt​(int version)
      Returns whether the user agent is an older version of IE.

      Returns whether the agent is an IE version older than the given version.

      See Also:
      agentIsIE()
    • agentIsIEMobile

      public boolean agentIsIEMobile()
      Returns whether the user agent is Internet Explorer Mobile.

      Returns also true when the agent is Internet Explorer 5 or older.

      See Also:
      getAgent()
    • agentIsOpera

      public boolean agentIsOpera()
      Returns whether the user agent is Opera.

      See Also:
      getAgent()
    • agentIsWebKit

      public boolean agentIsWebKit()
      Returns whether the user agent is WebKit-based.

      Webkit-based browsers include Safari, Chrome, Arora and Konquerer browsers.

      See Also:
      getAgent()
    • agentIsMobileWebKit

      public boolean agentIsMobileWebKit()
      Returns whether the user agent is Mobile WebKit-based.

      Mobile Webkit-based browsers include the Android Mobile WebKit and the iPhone Mobile WebKit browsers.

      See Also:
      getAgent()
    • agentIsSafari

      public boolean agentIsSafari()
      Returns whether the user agent is Safari.

      See Also:
      getAgent()
    • agentIsChrome

      public boolean agentIsChrome()
      Returns whether the user agent is Chrome.

      See Also:
      getAgent()
    • agentIsGecko

      public boolean agentIsGecko()
      Returns whether the user agent is Gecko-based.

      Gecko-based browsers include Firefox.

      See Also:
      getAgent()
    • getServer

      public WtServlet getServer()
      Returns the servlet.

      This returns the servlet environment of this session.

    • isInternalPathUsingFragments

      public boolean isInternalPathUsingFragments()
      Returns whether internal paths are implemented using URI fragments.

      This may be the case for older non-HTML5 browsers which do not support HTML5 History APIs.

    • supportsCss3Animations

      public boolean supportsCss3Animations()
      Returns whether this agent supports CSS3 animations.
    • isTest

      public boolean isTest()
      Returns whether this is a mocked test environment.