What is the PHP/Java Bridge?
----------------------------

  The PHP/Java Bridge is a network protocol which can be used to
  connect PHP with a java or ECMA 335 VM.

  Please read the ABOUT.HTM contained in the download archive or
  http://php-java-bridge.sf.net for more information.


Build and execution instructions:
---------------------------------
  NOTE: If you run Security Enhanced Linux, you must update the policy
  and tag the files with the correct SEL contexts, please see below, or 
  please install the binary RPM instead.

  In the directory php-java-bridge-p.x.y type:

          java -version        # 1.4 or above (1.5 or 1.6 recommended)
          gcc --version        # 3.2.3 or above (4.0.x recommended)
          apachectl -version   # Apache 1.3 or above (2.x recommended)
          php-config --version # PHP 4.3.0 or above (5.x or 6.x recommended)
          make null --version  # GNU make 3.79 or above

          phpize && 
          ./configure --with-java=/opt/IBMJava2-14 \
                      --disable-servlet \
                      --disable-script \ 
                      --disable-faces &&
          make &&
          su -c "make install"

  If your administrator allows you to dynamically load extensions, you
  can now test the extension by invoking the test.php with the 
  command: php ./test.php.

  Please see the output of ./configure --help=recursive for further
  configure options.

------------------------------------
   Permanently activate the module
   -------------------------------

  The bridge consists of two parts, the "frontent", usually Apache/PHP
  and our "java.so", and the "backend". The following describes how to
  start the backend (if necessary) and how to configure the frontend to
  use it.

  To permanently activate the frontend for all users please add the
  following lines to the php.ini or add a file java.ini to the
  directory that contains the php module descriptions (usually
  /etc/php.d/) with the following content:

          extension = java.so
          [java]
          java.log_level="3"
          java.log_file="/var/log/php-java-bridge.log"
          java.socketname="/var/run/.php-java-bridge_socket"


  OPTION 1: "Local backend using a service script."
  You can use local sockets to connect to a local backend. Copy the
  executable php-java-bridge to /usr/sbin, make it executable with the
  command "chmod +x /usr/sbin/php-java-bridge".

  This option can be used if "Security Enhanced Linux" is switched on.
  It cannot be used in a multi-user environment where each user wants
  to run his/her own instance of the backend.


  OPTION 2: "The J2EE backend."
  You can deploy the PHP/Java Bridge into a standard servlet engine or
  an application server. Deploy JavaBridge.war using the application
  server's tools. Disable the java.socketname and java.log_file option
  and set the java.hosts and java.servlet option, for example:

          extension = java.so
          [java]
          java.log_level="3"
          java.servlet=On
          java.hosts="127.0.0.1:8080"

  This option can be used if "Security Enhanced Linux" is switched
  on. It can be used in a multi-user environment, users can install
  their own .war files and customize them as necessary. It can also
  be used if Apache or IIS are not available, the .war files can be
  configured to connect to a system FCGI php server or to run a php
  CGI binary for each php request.


  OPTION 3: "Local backend as an apache sub-process".
  You can start the bridge as a sub-process of apache. Disable
  java.socketname, java.servlet and java.hosts. For example:

          extension = java.so
          [java]
          java.log_level="3"
          java.log_file="/var/log/php-java-bridge.log"

  This option cannot be used if "Security Enhanced Linux" is switched
  on.


  Option 4: "JSR 223 Scripting API."
  You can use the java script API to allocate and to invoke php
  instances from a HTTP pool. Disable java.socketname and set
  java.servlet. For example:

          extension = java.so
          [java]
          java.servlet=On

  After that you can call out to your web server's php scripts, for
  example:

     <?php

       function hello() {return "Hello java world!";}

       // call() checks for HTTP request header X_JAVABRIDGE_CONTEXT
       java_context()->call(java_closure()) ||die("Call test.php from java!");
     ?>

     PhpScriptEngine engine = new PhpScriptEngine();

     // Use a URLReader "adapter" to pass the apache URL to the engine.
     // engine.eval will create a php continuation on the web server ...
     engine.eval(new URLReader(new URL("http://127.0.0.1/test.php")));

     //...and call procedures within the allocated continuation...
     String s=((Invocable)engine).invoke("hello", new Object[]{});
     System.out.println("test.php::hello() returned: "+s);

     //.. release the allocated continuation:
     engine.release();

  This option can be used if "Security Enhanced Linux" is switched
  on. It requires php-script.jar, please see the --enable-script
  configure option above. Furthermore this option is required if you
  want to run php from a framework such as "Java Server Faces". You can
  build the required php-faces.jar using the --enable-faces configure
  option. For other frameworks (e.g. "Struts") you must write your own
  PhpStrutsScriptContextFactory.java, PhpStrutsScriptContext.java and
  PhpStrutsScriptEngine.java. You can use the php faces implementation
  as a template.

  After you have created the correct .ini entries, start the backend:

          Example for option #1: /usr/sbin/php-java-bridge

          Example for option #2: /etc/init.d/tomcat5 restart

          Example for option #3: apachectl restart

          Example for option #4: <not needed, backend is the calling VM itself>

  Note that the above options are exclusive; if you switch off the 
  java.socketname and try to start the local backend using the service
  script, the script will complain that the socketname is not set.

  Check the status:

          echo "<?php phpinfo()?>" | php | fgrep "java status"

  Other configuration options which should have been set up by the
  configure script but which can be changed later are:

          java.libpath   = <system dependent path to natcJavaBridge.so>
          java.classpath = <system dependent path to JavaBridge.jar>
          java.java_home = <system dependent path to the java install dir>
          java.java      = <system dependent path to the java binary>
          java.socketname= <local ("unix domain") communication channel>
          java.hosts     = <add. backends e.g.: server1:9267;server2:9268>
          java.servlet   = <On/Off>

  Please first look at the output of phpinfo() to see the original
  values.  

---------------------------------------------
  Starting the PHP/Java Bridge automatically
  ------------------------------------------

  When the java.socketname and java.hosts options are not set, the web
  server will start or re-start the bridge automatically as a sub
  component when the http service is started or re-started.

  However, when running the bridge in a production environment, it is
  recommended to start the PHP/Java Bridge as a system service,
  independent of the web server. On SysV based init systems the
  "php-java-bridge.service" can be used to automatically start and stop
  the bridge as a system service.  Please see the RedHat RPM download
  for an example.

------------------------------------
  Sample settings for Apache/Tomcat
  ---------------------------------

  Assuming that tomcat is installed (e.g. in /opt/tomcat5),
  JavaBridge.war is deployed (e.g. in /opt/tomcat5/webapps), java.so
  (or php_java.dll) is installed in the php modules directory (e.g. in
  /usr/lib/php/modules/), mod_jk and php5 are installed in the apache modules
  directory (e.g. in /usr/lib/httpd/modules/), we recommend following
  settings:


  The following settings in httpd.conf direct all .jsp requests to the
  tomcat servlet engine and all .php requests to the php module:

    httpd.conf:
    ----------
    LoadModule php5_module        modules/libphp5.so
    LoadModule jk_module          modules/mod_jk.so

    AddType application/x-httpd-php .php
    JkAutoAlias /opt/tomcat5/webapps
    JkMount /JavaBridge/*.jsp ajp13
    JkMount /JavaBridge/ ajp13


  The following settings in php.ini direct all php "Java(...)" calls to
  the tomcat servlet engine:

    php.ini:
    --------
    extension = java.so
    ;; on windows: extension = php_java.dll
    [java]
    java.hosts     = "127.0.0.1:8080"
    java.servlet   = On

  To check the above settings, please visit http://localhost/JavaBridge/
  and run the sessionSharing.jsp and sessionSharing.php examples.

  Please don't misunderstand the role of the mod_jk adapter. 
  It is only used to "mount" the tomcat webapps directory into apache and
  to forward requests for .jsp files.  The mod_jk adapter does this by
  "copying" the non jsp files from the tomcat webapps directory into
  the apache document root directory at run-time.

  A more reasonable approach would be to remove mod_jk and to create a
  shared web directory for tomcat and apache. This is the default since
  RedHat Fedora 4.

  Most modern frameworks, Java Server Faces for example, require that
  you manually forward to the "backend", anyway. The code would look
  like:

  <?php
   ...
   function jsfValidateEntry($ctx, $arg, $value) { ...}

   // check if we're called from the framework, forward if call failed.
   java_context()->call(java_closure()) || header("Location: index.jsf");
  ?>
   
  So you probably won't miss mod_jk's automatic forward.

------------------------------------
  64 Bit issues
  -------------
  
  It is possible to compile the bridge into 64 bit code:

          phpize && ./configure --with-java=$JAVA_HOME
          make CFLAGS="-m64"
  
  The scripts expect that the default JVM found in
  $JAVA_HOME/bin/java is a 64 bit VM. Unfortunately this is not true
  for the SUN JDK (Linux and Solaris) installation. The SUN JDK
  installs the 64 bit VM in some sub-directory of $JAVA_HOME/bin. On
  Solaris9 this is $JAVA_HOME/bin/sparcv9. The location on Linux may
  depend on the architecture.

  Since there is no standard installation directory and we cannot
  blindly search all sub-directories, it is your job to direct the
  bridge to the 64 bit JVM.  The relevant php.ini entry is java.java,
  see install instructions above.

---------------------------------------------
  AS/Servlet with PHP CGI
  -----------------------

  Read the following instructions only if you don't want to use
  Apache or IIS.

  It is possible to run PHP from java. Unlike the JSR223 sample
  implementation, which uses the JNI interface to load/call the native
  php5 shared library, we use the Fast CGI interface to call the PHP
  binary and use a local channel to connect the two components. This is
  more reliable; in case a PHP instance crashes, it will not take down
  the whole servlet engine or application server.
  
  Please follow the AS or Tomcat installation instructions above, then
  visit http://localhost:8080/JavaBridge and run the supplied JSP and PHP
  examples.

  If the parameter name "use_fast_cgi" is enabled in the web.xml and a fcgi
  server does not listen on port 9667 and a fcgi binary can be found
  as either /usr/bin/php-cgi or /usr/bin/php or c:/php5/php-cgi.exe,
  then the backend automatically starts the fast cgi server on this
  computer, with the command:

    cd $HOME
    export X_JAVABRIDGE_OVERRIDE_HOSTS="/"
    export PHP_FCGI_CHILDREN="20"
    export PHP_FCGI_MAX_REQUESTS="500"
    /usr/bin/php-cgi -b 127.0.0.1:9667

  It starts when the VM starts and stops when the VM terminates.


  If that failed, the bridge searches for a cgi binary called:
  
    php-cgi-<architecture>-<os>.exe or

    php-cgi-<architecture>-<os>.sh or

    php-cgi-<architecture>-<os>

  in the directory WEB-INF/cgi/. On unix the binary must be executable, it
  is therefore recommended to always use a wrapper .sh script, for example:

  #!/bin/sh
  # This wrapper script reconstructs the executable permissions
  # which some zip or .war implementations do not preserve
  chmod +x ./php-cgi-i386-linux
  exec ./php-cgi-i386-linux

  Please see the README located in the directory WEB-INF/cgi/ for
  details.

  The <architecture> and <os> values are calculated as follows:

    System.getProperty("os.arch").toLowerCase();
    System.getProperty("os.name").toLowerCase();

  Please see the output of test.php for details.


  It is also possible to adjust the php_exec setting (see
  WEB-INF/web.xml), for example:

      <param-name>php_exec</param-name>
      <param-value>/usr/local/bin/php-cgi</param-value>

  or

      <param-name>php_exec</param-name>
      <param-value>c:/PHP/php-cgi.exe</param-value>

  In case your application server denies calling the cgi binary,
  either start a fast cgi server on port 9667 as a separate process, for
  example from a service script, or add a policy to the JavaBridge.war
  which allows execution of the cgi binary. This is AS
  specific. However, for a first test, switch off security checking in
  general by adding the following to the application server's JRE
  "java.policy" file:

    grant {
	permission java.security.AllPermission;
    };

------------------------------------
  Loading on-demand with dl()
  ---------------------------

  It is possible to load the bridge for each new request, for example
  with:

    <?php
    if (!extension_loaded('java')) {
      if (!dl("java.so")) {
        exit(1);
      }
    }
    phpinfo();
    ?>

  However, this feature is meant for testing, only.  For a production
  system it is recommended to compile PHP in safe mode (which switches
  off the dl() function) and to activate all modules in the global
  php ini file.

------------------------------------
  Recognized CFLAGS
  -----------------

  During compilation you can use the following CFLAGS.

   * -DJAVA_COMPILE_DEBUG: Enables the assert() statement and other
     debug code.
   
   * -DJAVA_COMPILE_DEBUG -O0 -g3: Include full debug information into
     the binary.

   * -m64: Build 64 bit code. Required if you run a 64 bit JVM.

   * -m32: Build 32 bit code. Required if you run a 32 bit JVM on a 64
     bit system.

   * -DCFG_JAVA_SOCKET_INET: Disables local ("unix domain") sockets on
      systems which support them. This is needed on FreeBSD if the java VM
      is a linux executable. It is also needed on those Mac OSX platforms
      which use special JNI libraries (Apple has made some incompatible
      and undocumented changes to the JNI header structure so that we cannot
      use the standard Sun or GNU Java JNI to create the natcJavaBridge.so).

  Example: make CFLAGS="-m64"

------------------------------------
  Log levels
  ----------

  You can set the java.log_level to 6 values:

   0: Log nothing, not even fatal errors.

   1: Log fatal system errors such as "out of memory error".

   2: Log java exceptions.

   3: Log verbose, e.g.: "loading jar xyz.jar from http://xy.com"

   4: Log debug messages, including the c/s communication protocol.

   5: Log method invocations. 

  The default log level is 2.  If java.log_level is missing, the
  backend uses the "default" log level supplied when the backend was
  started (the second argument after java -jar JavaBridge.jar ...).

---------------------------------------------
  GCJ/GNU Java issues
  -------------------
  
  Running the PHP/Java Bridge under GCJ/GNU Java is supported on Linux
  and Solaris only.  If you run FreeBSD 5.3, please use Sun, Blackdown
  or IBM java instead.

------------------------------------
  Security Enhanced Linux
  -----------------------

  SELinux is an implementation of a flexible and fine-grained
  mandatory access control architecture implemented in the Linux kernel.
  It is used in recent Linux distributions such as Debian or RedHat
  Fedora Core 3.

  A system component running on a SELinux kernel must declare
  exactly a) which resources of the operating system it needs in order
  to function properly and b) what it provides to other components.

  The PHP/Java Bridge distribution contains two policy files,
  "php-java-bridge.te" and "php-java-bridge.fc". The
  "php-java-bridge.te" declares the javabridge_t domain and the
  resources it requires.  httpd and user domains are granted connect, 
  read and write to the PHP/Java Bridge server socket, which is
  "@var/run/.php-java-bridge_socket" in the Linux abstract namespace,
  and file create/read/write in the tmp_t.  Everything else (connections
  to other servers, file access, ...) is currently denied.

  The "php-java-bridge.fc" contains the file contexts for the PHP/Java
  Bridge and the log.

  Installation:
  -------------
  The following discussion assumes that you have a RedHat Linux system
  and you are running SELinux with the targeted policy.

   1. Install selinux-policy-targeted-sources-*.rpm, for example with
      the command:

        rpm -i selinux-policy-targeted-sources-1.17.30-2.19.noarch.rpm

   2. Update the policy files with the PHP/Java Bridge policy:

        su -c "sh update_policy.sh /etc/selinux/targeted/src/policy"
      
  If the default policy is too restrictive and e.g. you want to use the
  PHP/Java Bridge to connect to your J2EE server(s), you can temporarily 
  set the policy to "permissive", for example with the command "setenforce
  Permissive". Connect to the server, then extract the permissions
  from the audit log, for example with the command "audit2allow -d", then
  append them at the end of the "php-java-bridge.te" file and load the
  updated policy into the kernel. Don't forget to switch back, for
  example with "setenforce Enforcing".

------------------------------------
  Loading user classes and libraries
  ----------------------------------

  Although it is possible to manipulate the java.classpath to direct
  java to individual classes, this "feature" should not be used.

  Custom libraries should be stored in one of the system directories,
  either /usr/share/java (or one of its sub-directories) or
  java.libpath/lib (or one of its sub-directories) and they shall have
  the following format: <name>-<version>.jar.  For example:

    /usr/share/java/batStore/batStore-1.0.jar.

  The global repository /usr/share/java shall be used if the library
  is for general interest, otherwise the java.libpath/lib repository may
  be used.  Please look up the java.libpath from the output
  of the test.php or from phpinfo().
  
  When Security Enhanced Linux is configured to allow the PHP/Java
  Bridge to make HTTP URL connections to different servers or if
  Security Enhanced Linux is switched off in the linux kernel, java
  libraries may also be loaded from HTTP URLs.

  Java libraries can be created from .class files with the following
  command:

    jar cvf myLibrary-0.1.jar *.class 
  

  The libraries can be linked into the php files at run-time with the
  command:

    java_require("<library1>;<libraryN>");

  For example:

    <?php
      // process order
      java_require("j2ee.jar;batStore/batStore-1.0.jar");

      order(...);
    ?>

  Since java does not yet support library versions, the PHP/Java
  Bridge must be reset after a new library version has been deployed.
  This can be done at runtime by calling the php function
  "java_reset()".
  (The ECMA 335 CLR supports multiple class versions very well so in
  theory the problem could also be solved by compiling the .jar file
  into a ECMA 335 dll, e.g. with the command: ikvmc batStore-1.0.jar,
  and to use assembly loading instead, please see the
  tests.mono+net/load_assembly.php for details).

------------------------------------
  Sun java platform issues
  ------------------------

  The sun java platform does not support java "modules". This causes
  certain problems when running java programs. When you compile a class
  foo which references a class bar and ship the class foo without
  providing bar, the sun java platform will not complain unless the user
  accidently calls a method which references the non-existing class. If
  this happens, a "NoClassDefFound" error is thrown. This error may
  not(!) indicate which class is missing and it certainly does not
  indicate which external library is missing. The tests.php4 folder
  contains two tests, noClassDefFound.php and noClassDefFound2.php which
  demonstrate this.

  To avoid this problem please document *exactly* (including the
  version number) which external libraries (.jar files) your software
  needs. If you have written software where certain methods require an
  optional library, please document this in the method header.

------------------------------------
  PHP 5 issues
  ------------

  All PHP 5 versions < 5.0.4 crash when the dl() function is
  used. They first unload the module and then try to invoke its
  shutdown method.

  If you use one of these versions, please add an entry to the
  php.ini, see install instructions above.

------------------------------------
  Security issues
  ---------------

  It is recommended to use the local backend on a Unix machine which
  supports abstract local ("unix domain") sockets. On these systems
  the communication channel is not visible and cannot be attacked. If
  you are running a Security Enhanced Linux kernel, which is standard
  since RHEL4 or FC3, the backend is also protected by the SEL policy.

  On other systems, such as Windows and Mac OSX or when the backend is
  running in a standard J2EE (servlet-, AS-) environment where local
  channels are not available, the bridge opens a TCP port on 9167
  (JavaBridge.jar) or 9267 (MonoBridge.exe) or 9567 (JavaBridge.war) 
  and binds to all(!) available network cards. When running as a
  CGI binary the port is 9567 (CGI) or 9667 (FastCGI) and only the
  loopback (127.0.0.1) interface is used.

  Please make sure that the ports in the range [9167, ..., 9667] are
  protected and cannot be accessed from the internet.

  In J2EE application servers where the security policy denies opening
  TCP sockets, the bridge uses a HTTP tunnel which is 50 times slower
  than a standard TCP socket. If you see the log message (at level INFO)
  that the bridge cannot use local channels, please either change the
  security policy or disallow all PUT requests from the internet. If you
  use Apache, mod jk adapter and Tomcat as described above, the adapter
  already denies routing PUT requests to the servlet engine.

------------------------------------
  UTF-8
  -----
  
  Since PHP does not support unicode, the PHP/Java Bridge uses UTF-8 to
  convert characters into the host representation. All strings are
  created with new String(..., "UTF-8") and all internal String->byte[]
  conversions use getBytes("UTF-8").
  
  If you have old PHP files which are not UTF-8 encoded, you can
  change the default encoding with java_set_file_encoding().  For
  example:

    java_set_file_encoding("ISO-8859-1");

  For a list of available encodings please see the documentation of
  the JVM's file.encoding system property.

  The java_set_file_encoding() primitive only affects java.lang.String
  creation and internal conversions, it does not alter the JVM's
  file.encoding system property nor does it change the behaviour of
  methods which use the file.encoding property, getBytes() for
  example.  If you use:
  
    $str=new Java ("java.lang.String", "Cześć! -- שלום -- Gr");
    echo $str->getBytes();

  the output conversion depends on the file.encoding system property
  which in turn depends on the process' LANG environment variable. You
  can check the file.encoding with the test.php script, see above.

  To be portable please do not use conversions which depend on the
  JVM's file.encoding. They are easy to avoid, the above example
  should have been written as:

    $str=new Java ("java.lang.String", "Cześć! -- שלום -- Gr");
    echo (string)$str;

------------------------------------
  Mailing List
  ------------

  Please report bugs/problems to the mailing list:

    php-java-bridge-users@lists.sourceforge.net

