func_sorcery.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Fairview 5 Engineering, LLC
 *
 * George Joseph <george.joseph@fairview5.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*! \file
 *
 * \brief Get a field from a sorcery object
 *
 * \author \verbatim George Joseph <george.joseph@fairview5.com> \endverbatim
 *
 * \ingroup functions
 *
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/app.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/sorcery.h"
 
/*** DOCUMENTATION
    <function name="AST_SORCERY" language="en_US">
        <synopsis>
            Get a field from a sorcery object
        </synopsis>
        <syntax>
            <parameter name="module_name" required="true">
                <para>The name of the module owning the sorcery instance.</para>
            </parameter>
            <parameter name="object_type" required="true">
                <para>The type of object to query.</para>
            </parameter>
            <parameter name="object_id" required="true">
                <para>The id of the object to query.</para>
            </parameter>
            <parameter name="field_name" required="true">
                <para>The name of the field.</para>
            </parameter>
            <parameter name="retrieval_method" required="false">
                <para>Fields that have multiple occurrences may be retrieved in two ways.</para>
                <enumlist>
                    <enum name="concat"><para>Returns all matching fields concatenated
                    in a single string separated by <replaceable>separator</replaceable>
                    which defaults to <literal>,</literal>.</para></enum>
 
                    <enum name="single"><para>Returns the nth occurrence of the field
                    as specified by <replaceable>occurrence_number</replaceable> which defaults to <literal>1</literal>.
                    </para></enum>
                </enumlist>
                <para>The default is <literal>concat</literal> with separator <literal>,</literal>.</para>
            </parameter>
            <parameter name="retrieval_details" required="false">
                <para>Specifies either the separator for <literal>concat</literal>
                or the occurrence number for <literal>single</literal>.</para>
            </parameter>
        </syntax>
    </function>
***/
 
static int sorcery_function_read(struct ast_channel *chan,
    const char *cmd, char *data, struct ast_str **buf, ssize_t len)
{
    char *parsed_data = ast_strdupa(data);
    RAII_VAR(struct ast_sorcery *, sorcery, NULL, ast_sorcery_unref);
    RAII_VAR(void *, sorcery_obj, NULL, ao2_cleanup);
    struct ast_variable *change_set;
    struct ast_variable *it_change_set;
    int found, field_number = 1, ix, method;
    char *separator = ",";
 
    enum methods {
        CONCAT,
        SINGLE,
    };
 
    AST_DECLARE_APP_ARGS(args,
        AST_APP_ARG(module_name);
        AST_APP_ARG(object_type);
        AST_APP_ARG(object_id);
        AST_APP_ARG(field_name);
        AST_APP_ARG(method);
        AST_APP_ARG(method_arg);
    );
 
    /* Check for zero arguments */
    if (ast_strlen_zero(parsed_data)) {
        ast_log(AST_LOG_ERROR, "Cannot call %s without arguments\n", cmd);
        return -1;
    }
 
    AST_STANDARD_APP_ARGS(args, parsed_data);
 
    if (ast_strlen_zero(args.module_name)) {
        ast_log(AST_LOG_ERROR, "Cannot call %s without a module name to query\n", cmd);
        return -1;
    }
 
    if (ast_strlen_zero(args.object_type)) {
        ast_log(AST_LOG_ERROR, "Cannot call %s with an empty object type\n", cmd);
        return -1;
    }
 
    if (ast_strlen_zero(args.object_id)) {
        ast_log(AST_LOG_ERROR, "Cannot call %s with an empty object name\n", cmd);
        return -1;
    }
 
    if (ast_strlen_zero(args.field_name)) {
        ast_log(AST_LOG_ERROR, "Cannot call %s with an empty field name\n", cmd);
        return -1;
    }
 
    if (ast_strlen_zero(args.method)) {
        method = CONCAT;
    } else {
        if (strcmp(args.method, "concat") == 0) {
            method = CONCAT;
            if (ast_strlen_zero(args.method_arg)) {
                separator = ",";
            } else {
                separator = args.method_arg;
            }
 
        } else if (strcmp(args.method, "single") == 0) {
            method = SINGLE;
            if (!ast_strlen_zero(args.method_arg)) {
                if (sscanf(args.method_arg, "%30d", &field_number) <= 0 || field_number <= 0 ) {
                    ast_log(AST_LOG_ERROR, "occurrence_number must be a positive integer\n");
                    return -1;
                }
            }
        } else {
            ast_log(AST_LOG_ERROR, "Retrieval method must be 'concat' or 'single'\n");
            return -1;
        }
    }
 
    sorcery = ast_sorcery_retrieve_by_module_name(args.module_name);
    if (!sorcery) {
        ast_log(AST_LOG_ERROR, "Failed to retrieve sorcery instance for module %s\n", args.module_name);
        return -1;
    }
 
    sorcery_obj = ast_sorcery_retrieve_by_id(sorcery, args.object_type, args.object_id);
    if (!sorcery_obj) {
        return -1;
    }
 
    change_set = ast_sorcery_objectset_create(sorcery, sorcery_obj);
    if (!change_set) {
        return -1;
    }
 
    ix=1;
    found = 0;
    for (it_change_set = change_set; it_change_set; it_change_set = it_change_set->next) {
 
        if (method == CONCAT && strcmp(it_change_set->name, args.field_name) == 0) {
            ast_str_append(buf, 0, "%s%s", it_change_set->value, separator);
            found = 1;
            continue;
        }
 
        if (method == SINGLE && strcmp(it_change_set->name, args.field_name) == 0  && ix++ == field_number) {
            ast_str_set(buf, len, "%s", it_change_set->value);
            found = 1;
            break;
        }
    }
 
    ast_variables_destroy(change_set);
 
    if (!found) {
        return -1;
    }
 
    if (method == CONCAT) {
        ast_str_truncate(*buf, -1);
    }
 
    return 0;
}
 
static struct ast_custom_function sorcery_function = {
    .name = "AST_SORCERY",
    .read2 = sorcery_function_read,
};
 
static int unload_module(void)
{
    return ast_custom_function_unregister(&sorcery_function);
}
 
static int load_module(void)
{
    return ast_custom_function_register(&sorcery_function);
}
 
AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Get a field from a sorcery object");