NAME
    Apache2::Translation - Configuring Apache dynamically

SYNOPSIS
      LoadModule perl_module /path/to/mod_perl.so
      PerlLoadModule Apache2::Translation
      PerlTransHandler Apache2::Translation
      PerlMapToStorageHandler Apache2::Translation
      TranslationEvalCache 1000
      TranslationKey MyKey
      <TranslationProvider DB>
          Database  dbi:mysql:dbname:host
          User      username
          Password  password
          Singleton 1
          Table     tablename
          Key       keycolumn
          Uri       uricolumn
          Block     blockcolumn
          Order     ordercolumn
          Action    actioncolumn
          Cachetbl  cachetablename
          Cachecol  cachecolumn
          Cachesize 1000
      </TranslationProvider>

      # another provider
      <TranslationProvider File>
          Configfile /path/to/config
      </TranslationProvider>

      # export our provider parameters
      <Location /config>
        SetHandler modperl
        PerlResponseHandler Apache2::Translation::Config
      </Location>

      # configuring the WEB interface
      PerlModule Apache2::Translation::Admin
      <Location /-/transadm/>
        SetHandler modperl
        PerlResponseHandler Apache2::Translation::Admin
      </Location>

INSTALLATION
     perl Makefile.PL
     make
     make test
     make install

DESCRIPTION
    As the name implies "Apache2::Translation" lives mostly in the URI
    Translation Phase. It is somehow similar to "mod_rewrite" but
    configuration statements are read at runtime, thus, allowing to
    reconfigure a server without restarting it.

    The actual configuration statements are read by means of a *Translation
    Provider*, a Perl class offering a particular interface, see below.
    Currently there are 3 providers implemented, Apache2::Translation::DB,
    Apache2::Translation::BDB, and Apache2::Translation::File.

    There is also a WEB interface (Apache2::Translation::Admin).

  An Example
    Let's begin with an example. Given some database table:

     id  key    uri      blk ord action
      1  front  :PRE:    0   0   Cond: $HOSTNAME !~ /^(?:www\.)xyz\.(?:com|de)$/
      2  front  :PRE:    0   1   Redirect: 'http://xyz.com'.$URI, 301
      3  front  :PRE:    1   0   Do: $CTX{lang}='en'
      4  front  :PRE:    1   1   Cond: $HOSTNAME =~ /de$/
      5  front  :PRE:    1   2   Do: $CTX{lang}='de'
      6  front  /static  0   0   File: $DOCROOT.'/'.$CTX{lang}.$MATCHED_PATH_INFO
      7  front  /appl1   0   0   Proxy: 'http://backend/'.$CTX{lang}.$URI
      8  front  /appl2   0   0   Proxy: 'http://backend/'.$URI.'?l='.$CTX{lang}
      9  front  /        0   0   Config: ['AuthName "secret"'], ['AuthType Basic']
     10  back   :PRE:    0   0   Cond: $r->connection->remote_ip ne '127.0.0.1'
     11  back   :PRE:    0   1   Error: 403, 'Forbidden by Apache2::Translation(11)'
     12  back   /appl1   0   0   PerlHandler: 'My::Application1'
     13  back   /appl2   0   0   PerlHandler: 'My::Application2'

    The "id" column in this table is not really necessary for
    "Apache2::Translation". But if you want to deploy
    Apache2::Translation::Admin you need it.

    Well, here we have a frontend/backend configuration. The frontend
    records are labeled with the key "front", the backend records with
    "back".

    When a request comes in first the records with ":PRE:" in the
    "uri"-field are examined. Suppose, a request for
    "http://abc.com/static/img.png" comes in. Record 1 (id=1) checks the
    "Host" header. The expression after "Cond:" is evaluated as Perl code.
    It obviously returns true. "Cond" stands for *condition*. But how does
    it affect the further workflow? Here "blk" and "ord" come in. All
    records with the same "key", "uri" and "blk" form a block. "ord" gives
    an order within this block. Within a block all actions are executed up
    to the first condition that is false.

    Now, because our condition in record 1 is true the action in record 2
    (within the same block) is executed. It redirects the browser with a
    HTTP code of 301 (MOVED PERMANENTLY) to "http://xyz.com/static/img.png".

    When the redirected request comes back the condition in record 1 is
    false. Hence, the next block (key=front, uri=:PRE:, blk=1) is evaluated.
    First a "lang" member of a context hash is set to "en". A "Do" action is
    similar to a condition, only its value is ignored. Record 4 then checks
    if the "Host" header matches "/de$/". If so, then record 5 sets the
    *language* to "de".

    Now, the records labeled with ":PRE:" are finished. The handler starts
    looking for blocks labeled with the request uri. That is, it looks for a
    block with key=front, uri=/static/img.png. None is found.

    Then it cuts off the last part of the uri (/img.png), repeats the lookup
    and finds record 6. The "File" action sets "$r->filename" to
    "$DOCROOT/en/img.png". "Apache2::Translation" provides some convenience
    variables. They are tied to members of the request record.
    $MATCHED_PATH_INFO contains the uri part cut off ("/img.png"). More on
    them below.

    Now another round is started and the next uri part is cut off. Record 9
    matches. We see a "Config" action that sets "AuthName" and "AuthType".

    At the end the translation handler checks if "$r->filename" was set and
    returns "Apache2::Const::OK" or "Apache2::Const::DECLINED" respectively.

    I think that example gives a general idea, what "Apache2::Translation"
    does.

  Processing States
    Internally "Apache2::Translation" is implemented as a state machine. It
    starts in the *START* state, where some variables are initialized. From
    there it shifts immediately to the *PREPOC* state. Here all ":PRE:"
    rules are evaluated. From *PREPROC* it shifts to *PROC*. Now the rules
    with real uris are examined. When the *DONE* state is reached processing
    is finished.

    There is a special state named *LOOKUPFILE*. It is only used for
    subrequests that don't have an URI. For such requests the URI
    translation phase of the request cycle is skipped. Hence a
    *PerlTransHandler* would never be called. Such requests are results of
    calling "$r->lookup_file" for example.

    To catch also such requests install "Apache2::Translation" both as
    *PerlTransHandler* as well as *PerlMapToStorageHandler*. Then if such a
    subrequest occures the handler enters the *LOOKLUPFILE* state instead of
    *PREPROC*. From *LOOKLUPFILE* it normally shifts to *PROC* unless it
    executes a "Restart" action. In that case it shifts to *PREPROC*.

    You have to set $MATCHED_URI to some initial value if you want to hop
    through the *PROC* phase. A still empty $MATCHED_URI shifts from *PROC*
    immediately to *DONE*.

    Note: The *LOOKUPFILE* stuff is still somewhat experimental.

    You can control the current state by means of the "State", "Done" and
    "Restart" actions.

  Blocks and Lists of Blocks
    Above, we have defined a block as all records with the same "key", "uri"
    and "block". The actions within a block are ordered by the "order"
    field.

    A list of blocks is then an ordered list of all blocks with the same
    "key" and "uri". The order is given by the "block" number.

  Actions
    An action starts with a key word optionally followed by a colon and some
    arguments. The key words are case insensitive.

    "Apache2::Translation" provides some environment for code snippets in
    actions. They are compiled into perl functions. The compiled result is
    cached. 2 variables, $r and %CTX, are provided plus a few convenience
    variables. $r is the current "Apache2::RequestRec". %CTX is a hash that
    can be used to store arbitrary data. This hash is not used by
    Apache2::Translation itself. It can be used to pass data between
    actions. But note, the hash is localized to the translation handler. So,
    it cannot be used to pass data between different phases of the apache
    request cycle. Use "$r->notes" or "$r->pnotes" for that.

    Do: perl_code
    Fixup: perl_code
        "Do" is the simplest action. The Perl code is evaluated in scalar
        context. The return value is ignored. "Fixup" is just the same save
        it is run in the *Fixup* phase

    Cond: perl_code
        This is almost the same as "Do". The return value is taken as
        boolean. If it is false, the current block is finished. Processing
        continues with the next block.

    Done
        "Done" finishes the current block list and transfers control to the
        next state. That means if encountered in *PREPROC* state it switches
        to *PROC*. If the current state is *PROC* then the translation
        handler ends here.

        This action is a combination of "State: next_state" and "Last", see
        below.

        Don't try to use "Done" to return from a subroutine. Use "Last"
        instead.

    File: string
        This action sets "$r->filename" to string. It is equivalent to

         Do: $FILENAME=do{ string }

    Doc: ?content_type?, string
        "string" is evaluated as well as "content_type" if given. Then a
        special "moperl" handler is installed that simply sets the given
        content type and prints out the string to the client. "content_type"
        is "text/plain" if omitted.

    Proxy: ?url?
        This tells Apache to forward the request to "url" as a proxy. "url"
        is optional. If ommitted "$r->unparsed_uri" is used. That means
        Apache must be used as a proxy by the browser.

    CgiScript: ?string?
        is equivalent to

         Do: $r->handler( 'cgi-script' );
         FixupConfig: ['Options ExecCGI']

        If "string" is given it is evaluated and the result is assigned to
        "$r->filename".

    PerlScript: ?string?
        is equivalent to

         Do: $r->handler( 'perl-script' );
         FixupConfig: ['Options ExecCGI'], ['PerlOptions +ParseHeaders']

        If "string" is given it is evaluated and the result is assigned to
        "$r->filename".

    PerlHandler: string
        In short this action tries to figure out what "string" means and
        calls it as "modperl" handler.

        In detail it installs a "Apache2::Translation::response" as
        "PerlResponseHandler". When called the handler evaluates "string"
        which results either in a subroutine name, a package name, a
        subroutine reference or an object or class that implements the
        "handler" method. If a package name is given it must implement a
        "handler" subroutine.

        If the given package is not yet loaded it is "require"ed.

        Then the resulting subroutine or method is called and $r is passed.

        Further, a "PerlMapToStorageHandler" is installed that skips the
        handling of "Directory" containers and ".htaccess" files. If not
        set, this handler also sets "path_info". Assumed,

         #uri        blk ord action
         /some/path  0   0   PerlHandler: ...

        and a request comes in for "/some/path/foo/bar". Then "path_info" is
        set to "/foo/bar".

    Config: list_of_strings_or_arrays
    FixupConfig: list_of_strings_or_arrays
        Surprisingly, these are the most complex actions of all.

        "Config" adds Apache configuration directives to the request in the
        *Map To Storage* phase before the default "MapToStorage" handler.
        Think of it as a kind of ".htaccess". "FixupConfig" does the same in
        the *Fixup* phase. While "Config" is used quite often "FixupConfig"
        is seldom required. It is used mainly to mend configurations that
        are spoiled by the default "MapToStorage" handler.

        Arguments to both actions are strings or arrays of one or two
        elements:

         Config: 'AuthName "secret"',
                 ['AuthType Basic'],
                 ['ProxyPassReverse http://...', '/path']

        To understand the different meaning, you have to know about how
        Apache applies its configuration to a request. Hence, let's digress
        a little.

        Each Apache directive is used in certain contexts. Some for example
        can occur only in server config context, that means outside any
        "Directory", "Location" or even "VirtualHost" container. "Listen" or
        "PidFile" are examples. Other directives insist on being placed in a
        container.

        Also, the point in time when a directive takes effect differs for
        different directives. "PidFile" is clearly applied during server
        startup before any request is processed. Hence, our "Config" action
        cannot apply "PidFile". It's simply too late. "AllowOverride" is
        applied to single requests. But since it affects the processing of
        ".htaccess" files it must be applied before that processing takes
        place. To make things even more confusing some directives take
        effect at several points in time. Consider

         Options FollowSymLinks ExecCGI

        "FollowSymLinks" is applied when Apache looks up a file in the file
        system, while "ExecCGI" influences the way the response is generated
        ages later.

        Apache solves this complexity by computing a configuration for each
        single request. As a starting point it uses the server default
        configuration. That is the configuration outside any "Location" or
        "Directory" for a virtual host. This basic configuration is assigned
        to the request just between the *Uri Translation Phase* and *Map to
        Storage*. At the very end of *Map to Storage* Apache's core *Map to
        Storage* handler incorporates matching "Directory" containers and
        ".htaccess" files into the request's current configuration.
        "Location" containers are merged after *Map to Storage* is finished.

        Our "Config" action is applied early in *Map to Storage*. That means
        it affects the way Apache maps the request file name computed to the
        file system, because that comes later. But it also means, your
        static configuration (config file based) overrides our "Config"
        actions. This limitation can be partly overcome using "FixupConfig"
        instead of "Config".

        Now, what does the various syntaxes mean? The simplest one:

         #uri      blk ord action
         /uri      0   0   Config: 'ProxyPassReverse http://my.backend.org'

        is very close to

         <Location /uri>
           ProxyPassReverse http://my.backend.org
         </Location>

        Only, it is applied before any "Directory" container takes effect.
        Note, the uri-argument to the "Location" container is the value of
        $MATCHED_URI, see below. This is also valid if the "Config" action
        is used from a "Call"ed block.

        The location uri is sometimes important. "ProxyPassReverse", for
        example, uses the path given to the location container for its own
        purpose.

        All other forms of "Config" are not influenced by $MATCHED_URI.

        These two:

         Config: ['ProxyPassReverse http://my.backend.org']
         Config: ['ProxyPassReverse /path http://my.backend.org', '']

        are equivalent to

         <Location />
           ProxyPassReverse http://my.backend.org
         </Location>

        Note, the location container uri differs.

        The first one of them is also the only form of "Config" available
        with mod_perl before 2.0.3.

        The next one:

         Config: ['ProxyPassReverse http://my.backend.org', '/path']

        is equivalent to

         <Location /path>
           ProxyPassReverse http://my.backend.org
         </Location>

        I have chosen "ProxyPassReverse" for this example because the
        "Location" container uri matters for this directive, see httpd docs.
        The following form of applying "ProxyPassReverse" outside of any
        container is not possible with "Apache2::Translation":

         ProxyPassReverse /path http://my.backend.org

        Now let's look at another example to see how "Directory" containers
        and ".htaccess" files are applied. "AllowOverride" controls which
        directives are allowed in ".htaccess" files. As said before Apache
        applies "Directory" containers and ".htaccess" files after our
        "Config" directives. Unfortunately, they are both applied in the
        same step. That means we can say:

         Config: 'AllowOverride Options'

        But if at least one "Directory" container from our "httpd.conf" is
        applied that says for example "AllowOverride AuthConfig" it will
        override our "Config" statement. So, if you want to control which
        directives are allowed in ".htaccess" files with
        "Apache2::Translation" then avoid "AllowOverride" in your
        "httpd.conf", especially the often seen:

         <Directory />
           AllowOverride None
         </Directory>

        Put it instead in a *PREPROC* rule:

         #uri     blk ord action
         :PRE:    0   0   Config: 'AllowOverride None'

        So subsequent rules can override it.

        A similar problem exists with "Options FollowSymlinks". This option
        affects directly the phase when "Directory" containers are applied.
        Hence, any such option from the "httpd.conf" cannot be overridden by
        a "Config" rule.

        In Apache 2.2 at least up to 2.2.4 there is a bug that prevents
        "Config: AllowOverride Options" from working properly. The reason is
        an uninitialized variable that is by cause 0, see
        <http://www.gossamer-threads.com/lists/apache/dev/327770#327770>

    Call: string, ?@params?
        Well, the name suggests it is calling a subroutine. Assume you have
        several WEB applications running on the same server, say one
        application for each department. Each department needs of course
        some kind of authorization:

         #uri      blk ord action
         AUTH      0   0   Config: "AuthName \"$ARGV[0]\""
         AUTH      0   1   Config: 'AuthType Basic'
         AUTH      0   2   Config: 'AuthUserFile /etc/htaccess/user/'.$ARGV[1]
         /dep1     0   0   Call: qw/AUTH Department_1 dep1/
         /dep2     0   0   Call: qw/AUTH Department_2 dep2/

        The "AUTH" in the "Call" actions refer to the "AUTH" block list in
        the "uri" column. An optional parameter list is passed via @ARGV.

        "Call" fetches the block list for a given uri and processes it. If a
        "Last" action is executed the processing of that block list is
        finished.

    Redirect: url, ?http_code?
        The "Redirect" action sends a HTTP redirect response to the client
        and abort the current request. The optional "http_code" specifies
        the HTTP response code. Default is 302 (MOVED TEMPORARILY).

        "Redirect" tries to make the outgoing "Location" header RFC2616
        conform. That means if the schema part is ommitted it figures out if
        it has to be "http" or "https". If a relative url is given an
        appropriate url is computed based on the current value of $URI.

        If the current request is the result of an internal redirect the
        redirecting request's status is changed to "http_code". Thus,
        "Redirect" works also for "ErrorDocument"s.

    Error: ?http_code?, ?message?
        "Error" aborts the entire request. A HTTP response is sent to the
        client. The optional "http_code" specifies the HTTP response code.
        The optional "message" is logged as reason to the "error_log".

        "http_code" defaults to 500 (INTERNAL SERVER ERROR), "message" to
        "unspecified error".

    Uri: string
        This action sets "$r->uri" to string. It is equivalent to

         Do: $URI=do{ string }

    Key: string
        "string" is evaluated in scalar context. The result is assigned to
        the current key. The new key takes effect if the list of blocks
        matching the current uri is finished.

        For example:

         id  key    uri      blk ord action
          1  dflt   :PRE:    0   0   Cond: $CLIENTIP eq '192.168.0.1'
          2  dflt   :PRE:    0   1   Key: 'spec'
          3  dflt   :PRE:    0   2   Do: $DEBUG=3
          4  dflt   :PRE:    1   0   Config: 'Options None'
          5  dflt   /        0   0   File: $DOCROOT.$URI
          6  spec   /        0   0   File: '/very/special'.$URI

        Here an entirely different directory tree is shown to a client with
        the IP address 192.168.0.1. In record 2 the current key is set to
        "spec" if the condition in record 1 matches. Also, $DEBUG is set in
        this case (record 3).

        The next block in record 4 is executed for all clients, because the
        key change is not in effect, yet.

        Records 5 and 6 are new lists of blocks. Hence, record 6 is executed
        only for 192.168.0.1 and record 5 for the rest.

        The action "Key: 'string'" is equivalent to "Do: $KEY='string'".

    Restart: ?newuri?, ?newkey?, ?newpathinfo?
        "Restart" restarts the processing from the *PREPROC* phase. The
        optional arguments ar evaluated and assumed to result in strings.
        "newuri" is then assigned to "$r->uri" and $MATCHED_URI. "newkey" is
        assigned to $KEY and "newpathinfo" to $MATCHED_PATH_INFO.

    State: string
        If you look for a premature exit from the current block list take
        the "Done" action.

        This action affects the current state directly. Thus, you can loop
        back to the *PREPROC* state from *PROC*. It is mostly used the
        prematurely finish the translation handler from the *PREPROC* state.
        As the "Key" action it takes effect, when the current list of blocks
        is finished.

        "string" is evaluated as perl code. It is expected to result in one
        of the following strings. If not, a warning is printed in the
        "error_log". State names are case insensitive:

            start
            preproc
            proc
            done

        The "State" action is similar to setting the convenience variable
        $STATE. Only in the latter case you must use the state constants,
        e.g. "$STATE=DONE".

    Last
        If you look for a premature exit from the current block list take
        the "Done" action.

        This action finishes the current list of blocks (just like a false
        condition finishes the current block). It is used together with
        "State" to finish the translation handler from a conditional block
        in the *PREPROC* state:

         :PRE:  0 0 Cond: $finish
         :PRE:  0 1 State: 'done'
         :PRE:  0 2 Last

        Another application of "Last" is to return from a "Call" action.

  Convenience Variables and Data Structures
    $URI
        tied to "$r->uri"

    $REAL_URI
        tied to "$r->unparsed_uri"

    $METHOD
        tied to "$r->method"

    $QUERY_STRING
        tied to "$r->args"

    $FILENAME
        tied to "$r->filename"

    $DOCROOT
        tied to "$r->document_root"

    $HOSTNAME
        tied to "$r->hostname"

    $PATH_INFO
        tied to "$r->path_info"

    $REQUEST
        tied to "$r->the_request"

    $HEADERS
        tied to "$r->headers_in"

    $C  tied to "$r->connection"

    $CLIENTIP
        tied to "$r->connection->remote_ip"

    $KEEPALIVE
        tied to "$r->connection->keepalive"

        For more information see Apache2::RequestRec.

    $MATCHED_URI
        tied to "$r->notes('Apache2::Translation::n::uri')"

    $MATCHED_PATH_INFO
        tied to "$r->notes('Apache2::Translation::n::pathinfo')"

        While in "PROC" state the incoming uri is split in 2 parts. The
        first part is matching the "uri" field of a database record. The
        second part is the rest. They can be accessed as $MATCHED_URI and
        $MATCHED_PATH_INFO.

    $KEY
        the current key.

        Tied to "$r->notes('Apache2::Translation::n::key')"

    $STATE
        the current processing state.

    $RC Normally, "Apache2::Translation" checks at the end if "$r->filename"
        is set. If so, it returns "Apache2::Const::OK" to its caller. If
        not, "Apache2::Const::DECLINED" is returned. The first alternative
        signals that the *Uri Translation Phase* is done and no further
        handlers are to be called in this phase. The second alternative says
        that subsequent handlers are to be called. Thus, "mod_alias" or the
        core translation handler see the request.

        Setting $RC your action decide what is returned.

        $RC is also set by the "PerlHandler" action. Modperl generated
        responses are normally not associated with a single file on disk.

    $DEBUG
        tied to "$r->notes('Apache2::Translation::n::debug')"

        If set to 1 or 2 debugging output is sent to the "error_log".

    %CTX
        a hash to store arbitrary data. It can be used to pass data between
        action blocks. But note, it is localized to the translation handler.
        So, it cannot be used to pass data between different phases of the
        apache request cycle. Use "$r->notes" or "$r->pnotes" for that.

APACHE CONFIGURATION DIRECTIVES
    After installed and loaded by

      PerlLoadModule Apache2::Translation

    in your "httpd.conf" "Apache2::Translation" is configured with the
    following directives:

    <TranslationProvider class> ... </TranslationProvider>
        Currently there are 3 provider classes implemented,
        Apache2::Translation::DB, Apache2::Translation::File and
        Apache2::Translation::BDB.

        The ellipsis represents configuration lines formatted as

         NAME   VALUE

        These lines are passed as parameters to the provider. "NAME" is case
        insensitive and is converted to lowercase before passed to the
        provider object. Spaces round "VALUE" are stripped off. If "VALUE"
        begins and ends with the same quotation character (double quote or
        single quote) they are also stripped off.

        If "VALUE" is not quoted or is quoted with double quote characters
        then it is subject to environment variable expansion. All substrings
        that match "${VAR}" are replaced by the environment variable "VAR".

        The provider object is then created by:

         $Apache2::Translation::class->new( NAME1=>VALUE1, NAME2=>VALUE2, ... );

        where "class" is exchanged by the actual provider name.

    TranslationProvider class param1 param2 ...
        This is an alternative way to specify translation provider
        parameters.

        Each parameter is expected to be a string formatted as

         NAME=VALUE

        There must be no spaces around the equal sign. The list is passed to
        the constructor of the provider class as named parameters:

         $Apache2::Translation::class->new( NAME1=>VALUE1, NAME2=>VALUE2, ... );

    TranslationKey initial-key
        This sets the initial value for the key. Default is the string
        "default".

    TranslationEvalCache number
        "Apache2::Translation" compiles all code snippets into functions and
        caches these functions. Normally, an ordinary hash is used for this.
        Strictly speaking this is a memory hole if your translation table
        changes. I think that can be ignored, if the number of requests per
        worker is limited, see "MaxRequestsPerChild". If you think this is
        too lax, put a number here.

        If set the cache is tied to Tie::Cache::LRU. The number of cached
        code snippets will then be limited by "number".

WHICH PROVIDER TO CHOOSE
    Unless you want to implement your own provider you can choose from these
    3:

    *   DB

        This is the provider implemented first. It uses a cache to store
        lookup results but at least one read (to fetch the version) is made
        for each request. Use it if you already have a DB engine at your
        site and if you don't mind the additional lookups.

    *   File

        This provider is very fast. It reads the complete config file into
        memory and refreshes it when modified. Hence come the greatest
        drawback. Each perl interpreter reads the file and needs all the
        memory to hold every rule. So with many rules and a high
        "MaxClients" directive it eats up much memory.

    *   BDB

        Choose this provider if you have many rules and a high "MaxClients"
        directive. Since most of the database is stored in shared memory by
        BerkeleyDB it is almost as fast as the "File" provider but its
        resource hunger is limited.

EXPORTING OUR PROVIDER PARAMETERS
    A WEB server can export its provider parameters by means of the
    Apache2::Translation::Config module. That can then be used by the admin
    interface to connect to that provider.

THE WEB ADMINISTRATION INTERFACE
    The simplest way to configure the WEB interface is this:

      PerlModule Apache2::Translation::Admin
      <Location /-/transadm/>
        SetHandler modperl
        PerlResponseHandler Apache2::Translation::Admin
      </Location>

    Note, here an extra PerlModule statement is necessary. If nothing else
    specified the provider that has handled the current request is used.

    Note, there is a slash at the end of the location statement. It is
    necessary to be specified. Also, the URL given to the browser to reach
    the WEB interface must end with a slash or with "/index.html".

    Another provider is given by creating an "Apache2::Translation::Admin"
    object:

      <Perl>
        $My::Transadmin=Apache2::Translation::Admin->new
             (provider_spec=>[File,
                              ConfigFile=>'/path/to/config']);
      </Perl>

      <Location /-/transadm/>
        SetHandler modperl
        PerlResponseHandler $My::Transadmin->handler
      </Location>

    Here the provider is specified in a way similar to the
    "TranslationProvider" statement above.

    Also, an URL can be given that links to an exported parameter set:

      <Perl>
        $My::Transadmin=Apache2::Translation::Admin->new
             (provider_url=>'http://host/config');
      </Perl>

    In this case "LWP::UserAgent" is used to fetch the parameters.

    Or you can create the provider object by yourself and pass it:

      <Perl>
        use Apache2::Translation::File;
        $My::Transadmin=Apache2::Translation::Admin->new
            (provider=>Apache2::Translation::File->new
                          (configfile=>'/path/to/config'));
      </Perl>

IMPLEMENTING A NEW PROVIDER
    A provider implements a certain interface that is documented in
    Apache2::Translation::_base.

SEE ALSO
    Apache2::Translation::DB
    Apache2::Translation::BDB
    Apache2::Translation::File
    Apache2::Translation::Admin
    Apache2::Translation::_base
    Apache2::Translation::Config
    mod_perl: http://perl.apache.org

TODO / WHISHLIST
    *   UI improvements

        Help system that provides a short explanation to the actions and
        perhaps convenience variables.

        Action selection box.

        More and better keyboard control.

    *   cleaning up the javascript code

        my.js could use redesign.

    *   auto-Done mode

        In this mode the the translation handler finishes the current state
        after processing the first block list. Most of my block lists have a
        "Done" action at the end. This would also require an "Continue"
        action that to go to the next block list thus overruling the
        auto-Done.

    *   user identities + access rights

    *   domain specific mode

        to delegate responsibility for certain domains to different user
        groups.

    *   some kind of *run-once* actions

        To initialize things.

    *   error_log hook

        Apache implements an "error_log" hook. If there were a perl
        interface to it one could direct error messages to separate files
        with "Apache2::Translation".

AUTHOR
    Torsten Foertsch, <torsten.foertsch@gmx.net>

SPONSORING
    Sincere thanks to Arvato Direct Services (http://www.arvato.com/) for
    sponsoring the initial version of this module.

COPYRIGHT AND LICENSE
    Copyright (C) 2005-2008 by Torsten Foertsch

    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

