mod_example.c

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     * true anywhere in the upstream configuration.
     */
    merged_config->congenital = (pconf->congenital | pconf->local);
    /*
     * If we're merging records for two different types of environment (server
     * and directory), mark the new record appropriately.  Otherwise, inherit
     * the current value.
     */
    merged_config->cmode =
        (pconf->cmode == nconf->cmode) ? pconf->cmode : CONFIG_MODE_COMBO;
    /*
     * Now just record our being called in the trace list.  Include the
     * locations we were asked to merge.
     */
    note = ap_pstrcat(p, "example_merge_dir_config(\"", pconf->loc, "\",\"",
                   nconf->loc, "\")", NULL);
    trace_add(NULL, NULL, merged_config, note);
    return (void *) merged_config;
}

/*
 * This function gets called to create a per-server configuration
 * record.  It will always be called for the "default" server.
 *
 * The return value is a pointer to the created module-specific
 * structure.
 */
static void *example_create_server_config(pool *p, server_rec *s)
{

    excfg *cfg;
    char *sname = s->server_hostname;

    /*
     * As with the example_create_dir_config() reoutine, we allocate and fill
     * in an empty record.
     */
    cfg = (excfg *) ap_pcalloc(p, sizeof(excfg));
    cfg->local = 0;
    cfg->congenital = 0;
    cfg->cmode = CONFIG_MODE_SERVER;
    /*
     * Note that we were called in the trace list.
     */
    sname = (sname != NULL) ? sname : "";
    cfg->loc = ap_pstrcat(p, "SVR(", sname, ")", NULL);
    trace_add(s, NULL, cfg, "example_create_server_config()");
    return (void *) cfg;
}

/*
 * This function gets called to merge two per-server configuration
 * records.  This is typically done to cope with things like virtual hosts and
 * the default server configuration  The routine has the responsibility of
 * creating a new record and merging the contents of the other two into it
 * appropriately.  If the module doesn't declare a merge routine, the more
 * specific existing record is used exclusively.
 *
 * The routine MUST NOT modify any of its arguments!
 *
 * The return value is a pointer to the created module-specific structure
 * containing the merged values.
 */
static void *example_merge_server_config(pool *p, void *server1_conf,
                                         void *server2_conf)
{

    excfg *merged_config = (excfg *) ap_pcalloc(p, sizeof(excfg));
    excfg *s1conf = (excfg *) server1_conf;
    excfg *s2conf = (excfg *) server2_conf;
    char *note;

    /*
     * Our inheritance rules are our own, and part of our module's semantics.
     * Basically, just note whence we came.
     */
    merged_config->cmode =
        (s1conf->cmode == s2conf->cmode) ? s1conf->cmode : CONFIG_MODE_COMBO;
    merged_config->local = s2conf->local;
    merged_config->congenital = (s1conf->congenital | s1conf->local);
    merged_config->loc = ap_pstrdup(p, s2conf->loc);
    /*
     * Trace our call, including what we were asked to merge.
     */
    note = ap_pstrcat(p, "example_merge_server_config(\"", s1conf->loc, "\",\"",
                   s2conf->loc, "\")", NULL);
    trace_add(NULL, NULL, merged_config, note);
    return (void *) merged_config;
}

/*
 * This routine is called after the request has been read but before any other
 * phases have been processed.  This allows us to make decisions based upon
 * the input header fields.
 *
 * The return value is OK, DECLINED, or HTTP_mumble.  If we return OK, no
 * further modules are called for this phase.
 */
static int example_post_read_request(request_rec *r)
{

    excfg *cfg;

    cfg = our_dconfig(r);
    /*
     * We don't actually *do* anything here, except note the fact that we were
     * called.
     */
    trace_add(r->server, r, cfg, "example_post_read_request()");
    return DECLINED;
}

/*
 * This routine gives our module an opportunity to translate the URI into an
 * actual filename.  If we don't do anything special, the server's default
 * rules (Alias directives and the like) will continue to be followed.
 *
 * The return value is OK, DECLINED, or HTTP_mumble.  If we return OK, no
 * further modules are called for this phase.
 */
static int example_translate_handler(request_rec *r)
{

    excfg *cfg;

    cfg = our_dconfig(r);
    /*
     * We don't actually *do* anything here, except note the fact that we were
     * called.
     */
    trace_add(r->server, r, cfg, "example_translate_handler()");
    return DECLINED;
}

/*
 * This routine is called to check the authentication information sent with
 * the request (such as looking up the user in a database and verifying that
 * the [encrypted] password sent matches the one in the database).
 *
 * The return value is OK, DECLINED, or some HTTP_mumble error (typically
 * HTTP_UNAUTHORIZED).  If we return OK, no other modules are given a chance
 * at the request during this phase.
 */
static int example_check_user_id(request_rec *r)
{

    excfg *cfg;

    cfg = our_dconfig(r);
    /*
     * Don't do anything except log the call.
     */
    trace_add(r->server, r, cfg, "example_check_user_id()");
    return DECLINED;
}

/*
 * This routine is called to check to see if the resource being requested
 * requires authorisation.
 *
 * The return value is OK, DECLINED, or HTTP_mumble.  If we return OK, no
 * other modules are called during this phase.
 *
 * If *all* modules return DECLINED, the request is aborted with a server
 * error.
 */
static int example_auth_checker(request_rec *r)
{

    excfg *cfg;

    cfg = our_dconfig(r);
    /*
     * Log the call and return OK, or access will be denied (even though we
     * didn't actually do anything).
     */
    trace_add(r->server, r, cfg, "example_auth_checker()");
    return DECLINED;
}

/*
 * This routine is called to check for any module-specific restrictions placed
 * upon the requested resource.  (See the mod_access module for an example.)
 *
 * The return value is OK, DECLINED, or HTTP_mumble.  All modules with an
 * handler for this phase are called regardless of whether their predecessors
 * return OK or DECLINED.  The first one to return any other status, however,
 * will abort the sequence (and the request) as usual.
 */
static int example_access_checker(request_rec *r)
{

    excfg *cfg;

    cfg = our_dconfig(r);
    trace_add(r->server, r, cfg, "example_access_checker()");
    return DECLINED;
}

/*
 * This routine is called to determine and/or set the various document type
 * information bits, like Content-type (via r->content_type), language, et
 * cetera.
 *
 * The return value is OK, DECLINED, or HTTP_mumble.  If we return OK, no
 * further modules are given a chance at the request for this phase.
 */
static int example_type_checker(request_rec *r)
{

    excfg *cfg;

    cfg = our_dconfig(r);
    /*
     * Log the call, but don't do anything else - and report truthfully that
     * we didn't do anything.
     */
    trace_add(r->server, r, cfg, "example_type_checker()");
    return DECLINED;
}

/*
 * This routine is called to perform any module-specific fixing of header
 * fields, et cetera.  It is invoked just before any content-handler.
 *
 * The return value is OK, DECLINED, or HTTP_mumble.  If we return OK, the
 * server will still call any remaining modules with an handler for this
 * phase.
 */
static int example_fixer_upper(request_rec *r)
{

    excfg *cfg;

    cfg = our_dconfig(r);
    /*
     * Log the call and exit.
     */
    trace_add(r->server, r, cfg, "example_fixer_upper()");
    return OK;
}

/*
 * This routine is called to perform any module-specific logging activities
 * over and above the normal server things.
 *
 * The return value is OK, DECLINED, or HTTP_mumble.  If we return OK, any
 * remaining modules with an handler for this phase will still be called.
 */
static int example_logger(request_rec *r)
{

    excfg *cfg;

    cfg = our_dconfig(r);
    trace_add(r->server, r, cfg, "example_logger()");
    return DECLINED;
}

/*
 * This routine is called to give the module a chance to look at the request
 * headers and take any appropriate specific actions early in the processing
 * sequence.
 *
 * The return value is OK, DECLINED, or HTTP_mumble.  If we return OK, any
 * remaining modules with handlers for this phase will still be called.
 */
static int example_header_parser(request_rec *r)
{

    excfg *cfg;

    cfg = our_dconfig(r);
    trace_add(r->server, r, cfg, "example_header_parser()");
    return DECLINED;
}

/*--------------------------------------------------------------------------*/
/*                                                                          */
/* All of the routines have been declared now.  Here's the list of          */
/* directives specific to our module, and information about where they      */
/* may appear and how the command parser should pass them to us for         */
/* processing.  Note that care must be taken to ensure that there are NO    */
/* collisions of directive names between modules.                           */
/*                                                                          */
/*--------------------------------------------------------------------------*/
/* 
 * List of directives specific to our module.
 */
static const command_rec example_cmds[] =
{
    {
        "Example",              /* directive name */
        cmd_example,            /* config action routine */
        NULL,                   /* argument to include in call */
        OR_OPTIONS,             /* where available */
        NO_ARGS,                /* arguments */
        "Example directive - no arguments"
                                /* directive description */
    },
    {NULL}
};

/*--------------------------------------------------------------------------*/
/*                                                                          */
/* Now the list of content handlers available from this module.             */
/*                                                                          */
/*--------------------------------------------------------------------------*/
/* 
 * List of content handlers our module supplies.  Each handler is defined by
 * two parts: a name by which it can be referenced (such as by
 * {Add,Set}Handler), and the actual routine name.  The list is terminated by
 * a NULL block, since it can be of variable length.
 *
 * Note that content-handlers are invoked on a most-specific to least-specific
 * basis; that is, a handler that is declared for "text/plain" will be
 * invoked before one that was declared for "text / *".  Note also that
 * if a content-handler returns anything except DECLINED, no other
 * content-handlers will be called.
 */
static const handler_rec example_handlers[] =
{
    {"example-handler", example_handler},
    {NULL}
};

/*--------------------------------------------------------------------------*/
/*                                                                          */
/* Finally, the list of callback routines and data structures that          */
/* provide the hooks into our module from the other parts of the server.    */
/*                                                                          */
/*--------------------------------------------------------------------------*/
/* 
 * Module definition for configuration.  If a particular callback is not
 * needed, replace its routine name below with the word NULL.
 *
 * The number in brackets indicates the order in which the routine is called
 * during request processing.  Note that not all routines are necessarily
 * called (such as if a resource doesn't have access restrictions).
 */
module MODULE_VAR_EXPORT example_module =
{
    STANDARD_MODULE_STUFF,
    example_init,               /* module initializer */
    example_create_dir_config,  /* per-directory config creator */
    example_merge_dir_config,   /* dir config merger */
    example_create_server_config,       /* server config creator */
    example_merge_server_config,        /* server config merger */
    example_cmds,               /* command table */
    example_handlers,           /* [9] list of handlers */
    example_translate_handler,  /* [2] filename-to-URI translation */
    example_check_user_id,      /* [5] check/validate user_id */
    example_auth_checker,       /* [6] check user_id is valid *here* */
    example_access_checker,     /* [4] check access by host address */
    example_type_checker,       /* [7] MIME type checker/setter */
    example_fixer_upper,        /* [8] fixups */
    example_logger,             /* [10] logger */
#if MODULE_MAGIC_NUMBER >= 19970103
    example_header_parser,      /* [3] header parser */
#endif
#if MODULE_MAGIC_NUMBER >= 19970719
    example_child_init,         /* process initializer */
#endif
#if MODULE_MAGIC_NUMBER >= 19970728
    example_child_exit,         /* process exit/cleanup */
#endif
#if MODULE_MAGIC_NUMBER >= 19970902
    example_post_read_request   /* [1] post read_request handling */
#endif
};