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 4.3.4 or above (5.x or 6.x recommended)
          make null --version  # GNU make 3.79 or above

          phpize && 
          ./configure --with-java=/opt/IBMJava2-141 &&
          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 php java extension, and a "backend". The following
  describes how to start the backend (if necessary) and how to configure
  the frontend so that it connects to the backend.

  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 ;; php_java.dll on windows


  To direct the extension to a specific backend, please add the
  following lines to the php.ini. Or add a file java-<backend>.ini,
  e.g. "java-tomcat.ini" or "java-standalone.ini" to the directory that
  contains the php module descriptions, usually /etc/php.d/, with the
  following content. Options:

  1) java.socketname, java.hosts and java.servlet not set: local
  backend which starts automatically (default). Example #1:

  ;; empty


  Example #2 uses java.java_home, java.java to set the java
  executable. Vendors may also set java.wrapper to set the default
  java VM options:
 
  [java]
  java.java_home = /opt/jdk1.5
  java.java      = /opt/jdk1.5/bin/java
  java.log_file  = /var/log/php-java-bridge.log
  java.log_level = 3
 
 
  2) java.socketname set: local system backend started by the
  system "php-java-bridge" service script. Example:
 
  [java]
  java.java_home  = /opt/jdk1.5
  java.java       = /opt/jdk1.5/bin/java
  java.log_file   = /var/log/php-java-bridge.log
  java.log_level  = 3
  java.socketname = /var/run/.php-java-bridge_socket
 
 
  3) java.hosts set: external backend(s) on different server(s). The
  backends can be started on these servers with e.g.: java -jar
  JavaBridge.jar. Example:
 
  [java]
  java.hosts     = 192.168.5.203:9267 192.168.5.204:9267
  java.log_level = 3
 
 
  4) java.hosts=127.0.0.1:<port> and java.servlet=MultiUser: user
  backend(s) deployed into a local j2ee application server with a shared
  document root directory (see DocumentRoot setting in the
  httpd.conf). Several JavaBridge backends, e.g. "MyBridge.war" or
  "Bridge31.war", can coexist in the same j2ee server. If the Apache or
  IIS server uses the same document root as the j2ee server, the
  frontent automatically connects to the associated "MyBridge" or
  "Bridge31" backend. Example:
 
  [java]
  java.hosts     = 127.0.0.1:8080
  java.servlet   = MultiUser
  java.log_level = 3
 
 
  5) java.hosts set and java.servlet=On: "JavaBridge.war" backend
  deployed into a j2ee application server or servlet engine. Example:
 
  [java]
  java.hosts     = 127.0.0.1:8080
  java.servlet   = On
  java.log_level = 3

 
  6) Standalone java application (see JSR223) or AS or servlet engine
  without Apache or IIS frontend. A PHP server can be started with the
  command (e.g.): X_JAVABRIDGE_OVERRIDE_HOSTS="/" PHP_FCGI_CHILDREN="20"
  PHP_FCGI_MAX_REQUESTS="500" php-cgi -c java.ini -b 127.0.0.1:9667. 
  php-cgi starts automatically if no PHP server is listening on port 9667.
 
  log_errors     = On
  display_errors = Off
  [java]
  java.log_level = 3


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

  #1: Not needed, backend starts automatically
  #2: /usr/sbin/php-java-bridge
  #3: java -jar JavaBridge.jar INET:9267 3 php-java-bridge.log
  #4: service tomcat5 restart
  #5: service tomcat5 restart
  #6: Not needed, backend is the calling VM 

  The Linux RPM binaries use the following options:

  php-java-bridge*.rpm            : Option #1
  php-java-bridge-standalone*.rpm : Option #2
  php-java-bridge-tomcat*.rpm     : Option #5
  php-java-bridge-devel*.rpm      : Option #6
   

  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/MultiUser>, see NEWS for version 3.0.2
  java.wrapper   = Reserved for OS vendor

  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 use a J2EE backend, Tomcat5 for example.

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

  Assuming that tomcat is installed (e.g. in /opt/tomcat5),
  MyJavaBridge.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   = MultiUser ;; or: /MyJavaBridge/JavaBridge.php

  To check the above settings, please visit http://localhost/MyJavaBridge/
  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 set to "Autostart" 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 apache or IIS or start a fast cgi server on port 9667
  as a separate process, for example from a service script. 

  On Unix the bridge uses named pipes. On Windows, where standard
  named pipes are not available, the bridge uses TCP sockets. If your
  application server denies socket accept/resolve, please either run the
  AS on a Unix operating system or add the following lines to your AS
  policy file (for example ...\domains\domain1\config\server.policy):

    grant {
      permission java.net.SocketPermission  "*", "accept,resolve";
    };


------------------------------------
  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="-O0 -g3"

------------------------------------
  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 -l -i /var/log/audit/audit.log", 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
  ---------------

  The bridge uses abstract local sockets, named pipes (located in
  /dev/shm/ or /tmp/) or local TCP sockets as communication channels.

  It is recommended to use the local backend on a Unix machine which
  supports abstract local ("unix domain") sockets or named pipes. 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. The servlet backend uses a HTTP tunnel to execute one
  statement and then switches to named pipes for the rest of the
  communication.

  On other systems, such as Windows and Mac OSX, the bridge opens a
  local TCP port on 9167 (MonoBridge.exe) or 9267 (JavaBridge.jar), 9567
  (JavaBridge.war) or 9667 (FastCGI). Please make sure that the ports in
  the range [9167, ..., 9667] cannot be accessed from the internet.

------------------------------------
  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;  // in PHP5 or higher
    echo $str->toString(); // in PHP4

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

  Please report bugs/problems to the mailing list:

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

