func_json.c File Reference

JSON parsing function. More...

#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/utils.h"
#include "asterisk/test.h"
#include "asterisk/app.h"
#include "asterisk/conversions.h"

Include dependency graph for func_json.c:

Go to the source code of this file.

Macros
#define	MAX_JSON_STACK   32

Enumerations
enum	json_option_flags { OPT_COUNT = (1 << 0) }

Functions
	AST_MODULE_INFO_STANDARD_EXTENDED (ASTERISK_GPL_KEY, "JSON decoding function")
	AST_THREADSTORAGE_CUSTOM_SCOPE (result_buf, NULL, ast_free_ptr, static)
static int	json_decode_read (struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
static int	load_module (void)
static int	parse_node (char **key, char *currentkey, char *nestchar, int count, struct ast_json *json, char *buf, size_t len, int *depth)
static int	unload_module (void)

Variables
static struct ast_custom_function	json_decode_function
static const struct ast_app_option	json_options [128] = { [ 'c' ] = { .flag = OPT_COUNT }, }

Detailed Description

JSON parsing function.

Author

Naveen Albert aster.nosp@m.isk@.nosp@m.phrea.nosp@m.knet.nosp@m..org

Definition in file func_json.c.

Macro Definition Documentation

MAX_JSON_STACK

#define MAX_JSON_STACK   32

Definition at line 95 of file func_json.c.

Enumeration Type Documentation

json_option_flags

enum json_option_flags

Enumerator
OPT_COUNT

Definition at line 87 of file func_json.c.

                       {
    OPT_COUNT = (1 << 0),
};

Function Documentation

AST_MODULE_INFO_STANDARD_EXTENDED()

AST_MODULE_INFO_STANDARD_EXTENDED	(	ASTERISK_GPL_KEY	,
		"JSON decoding function"
	)

AST_THREADSTORAGE_CUSTOM_SCOPE()

AST_THREADSTORAGE_CUSTOM_SCOPE	(	result_buf	,
		NULL	,
		ast_free_ptr	,
		static
	)

json_decode_read()

static int json_decode_read ( struct ast_channel *  chan, const char *  cmd, char *  data, char *  buf, size_t  len  )

static

Definition at line 195 of file func_json.c.

{
    int count = 0;
    struct ast_flags flags = {0};
    struct ast_json *json = NULL, *start = NULL;
    char *nestchar = "."; /* default delimeter for nesting key indexing is . */
    int index, res, depth = 0;
 
    AST_DECLARE_APP_ARGS(args,
        AST_APP_ARG(varname);
        AST_APP_ARG(key);
        AST_APP_ARG(nestchar);
        AST_APP_ARG(options);
    );
    char *varsubst, *key, *currentkey, *nextkey, *firstkey, *tmp;
    struct ast_str *str = ast_str_thread_get(&result_buf, 16);
 
    AST_STANDARD_APP_ARGS(args, data);
 
    if (!ast_strlen_zero(args.options)) {
        ast_app_parse_options(json_options, &flags, NULL, args.options);
        if (ast_test_flag(&flags, OPT_COUNT)) {
            count = 1;
        }
    }
 
    if (ast_strlen_zero(args.varname)) {
        ast_log(LOG_WARNING, "%s requires a variable name\n", cmd);
        return -1;
    }
 
    if (ast_strlen_zero(args.key)) {
        ast_log(LOG_WARNING, "%s requires a key\n", cmd);
        return -1;
    }
 
    key = ast_strdupa(args.key);
    if (!ast_strlen_zero(args.nestchar)) {
        int seplen = strlen(args.nestchar);
        if (seplen != 1) {
            ast_log(LOG_WARNING, "Nesting separator '%s' has length %d and is invalid (must be a single character)\n", args.nestchar, seplen);
        } else {
            nestchar = args.nestchar;
        }
    }
 
    varsubst = ast_alloca(strlen(args.varname) + 4); /* +4 for ${} and null terminator */
    if (!varsubst) {
        ast_log(LOG_ERROR, "Failed to allocate string\n");
        return -1;
    }
    sprintf(varsubst, "${%s}", args.varname); /* safe, because of the above allocation */
    ast_str_substitute_variables(&str, 0, chan, varsubst);
 
    ast_debug(1, "Parsing JSON using nesting delimeter '%s'\n", nestchar);
 
    if (ast_str_strlen(str) == 0) {
        ast_debug(1, "Variable '%s' contains no data, nothing to search!\n", args.varname);
        return -1; /* empty json string */
    }
 
    /* allow for multiple key nesting */
    currentkey = key;
    firstkey = ast_strdupa(currentkey);
    tmp = strstr(firstkey, nestchar);
    if (tmp) {
        *tmp = '\0';
    }
 
    /* parse a string as JSON */
    ast_debug(1, "Parsing JSON: %s (key: '%s')\n", ast_str_buffer(str), currentkey);
    if (ast_strlen_zero(currentkey)) {
        ast_debug(1, "Empty JSON key\n");
        return -1;
    }
    if (ast_str_strlen(str) == 0) {
        ast_debug(1, "JSON node '%s', contains no data, nothing to search!\n", currentkey);
        return -1; /* empty json string */
    }
 
    json = ast_json_load_str(str, NULL);
    if (!json) {
        ast_log(LOG_WARNING, "Failed to parse as JSON: %s\n", ast_str_buffer(str));
        return -1;
    }
 
    /* parse the JSON object, potentially recursively */
    nextkey = strsep(&key, nestchar);
    if (ast_json_is_object(json)) {
        start = ast_json_object_get(json, firstkey);
    } else {
        if (ast_str_to_int(currentkey, &index)) {
            ast_debug(1, "Requested index '%s' is not numeric or is invalid\n", currentkey);
            return -1;
        }
        start = ast_json_array_get(json, index);
    }
 
    res = parse_node(&key, nextkey, nestchar, count, start, buf, len, &depth);
    ast_json_unref(json);
    return res;
}

References args, ast_alloca, AST_APP_ARG, ast_app_parse_options(), ast_debug, AST_DECLARE_APP_ARGS, ast_json_array_get(), ast_json_is_object(), ast_json_load_str(), ast_json_object_get(), ast_json_unref(), ast_log, AST_STANDARD_APP_ARGS, ast_str_buffer(), ast_str_strlen(), ast_str_substitute_variables(), ast_str_thread_get(), ast_str_to_int(), ast_strdupa, ast_strlen_zero(), ast_test_flag, buf, ast_flags::flags, json_options, len(), LOG_ERROR, LOG_WARNING, NULL, OPT_COUNT, options, parse_node(), str, and strsep().

load_module()

static int load_module ( void  )

static

Definition at line 407 of file func_json.c.

{
    int res;
 
#ifdef TEST_FRAMEWORK
    AST_TEST_REGISTER(test_JSON_DECODE);
#endif
    res = ast_custom_function_register(&json_decode_function);
 
    return res;
}

References ast_custom_function_register, AST_TEST_REGISTER, and json_decode_function.

parse_node()

static int parse_node ( char **  key, char *  currentkey, char *  nestchar, int  count, struct ast_json *  json, char *  buf, size_t  len, int *  depth  )

static

Definition at line 97 of file func_json.c.

{
    const char *result = NULL;
    char *previouskey;
    struct ast_json *jsonval = json;
 
    /* Prevent a huge JSON string from blowing the stack. */
    (*depth)++;
    if (*depth > MAX_JSON_STACK) {
        ast_log(LOG_WARNING, "Max JSON stack (%d) exceeded\n", MAX_JSON_STACK);
        return -1;
    }
 
    snprintf(buf, len, "%s", ""); /* clear the buffer from previous round if necessary */
    if (!json) { /* no error or warning should be thrown */
        ast_debug(1, "Could not find key '%s' in parsed JSON\n", currentkey);
        return -1;
    }
 
    switch(ast_json_typeof(jsonval)) {
        unsigned long int size;
        int r;
        double d;
 
        case AST_JSON_STRING:
            result = ast_json_string_get(jsonval);
            ast_debug(1, "Got JSON string: %s\n", result);
            ast_copy_string(buf, result, len);
            break;
        case AST_JSON_INTEGER:
            r = ast_json_integer_get(jsonval);
            ast_debug(1, "Got JSON integer: %d\n", r);
            snprintf(buf, len, "%d", r); /* the snprintf below is mutually exclusive with this one */
            break;
        case AST_JSON_REAL:
            d = ast_json_real_get(jsonval);
            ast_debug(1, "Got JSON real: %.17g\n", d);
            snprintf(buf, len, "%.17g", d); /* the snprintf below is mutually exclusive with this one */
            break;
        case AST_JSON_ARRAY:
            ast_debug(1, "Got JSON array\n");
            previouskey = currentkey;
            currentkey = strsep(key, nestchar); /* retrieve the desired index */
            size = ast_json_array_size(jsonval);
            ast_debug(1, "Parsed JSON array of size %lu, key: %s\n", size, currentkey);
            if (!currentkey) { /* this is the end, so just dump the array */
                if (count) {
                    ast_debug(1, "No key on which to index in the array, so returning count: %lu\n", size);
                    snprintf(buf, len, "%lu", size);
                    return 0;
                } else {
                    char *result2 = ast_json_dump_string(jsonval);
                    ast_debug(1, "No key on which to index in the array, so dumping '%s' array\n", previouskey);
                    ast_copy_string(buf, result2, len);
                    ast_json_free(result2);
                }
            } else if (ast_str_to_int(currentkey, &r) || r < 0) {
                ast_debug(1, "Requested index '%s' is not numeric or is invalid\n", currentkey);
            } else if (r >= size) {
                ast_debug(1, "Requested index '%d' does not exist in parsed array\n", r);
            } else {
                ast_debug(1, "Recursing on index %d in array\n", r);
                if (parse_node(key, currentkey, nestchar, count, ast_json_array_get(jsonval, r), buf, len, depth)) { /* recurse on this node */
                    return -1;
                }
            }
            break;
        case AST_JSON_TRUE:
        case AST_JSON_FALSE:
            r = ast_json_is_true(jsonval);
            ast_debug(1, "Got JSON %s for key %s\n", r ? "true" : "false", currentkey);
            snprintf(buf, len, "%d", r); /* the snprintf below is mutually exclusive with this one */
            break;
        case AST_JSON_NULL:
            ast_debug(1, "Got JSON null for key %s\n", currentkey);
            break;
        case AST_JSON_OBJECT:
            ast_debug(1, "Got generic JSON object for key %s\n", currentkey);
            previouskey = currentkey;
            currentkey = strsep(key, nestchar); /* retrieve the desired index */
            if (!currentkey) { /* this is the end, so just dump the object */
                char *result2 = ast_json_dump_string(jsonval);
                ast_copy_string(buf, result2, len);
                ast_json_free(result2);
            } else {
                ast_debug(1, "Recursing on object (key was '%s' and is now '%s')\n", previouskey, currentkey);
                if (parse_node(key, currentkey, nestchar, count, ast_json_object_get(jsonval, currentkey), buf, len, depth)) { /* recurse on this node */
                    return -1;
                }
            }
            break;
        default:
            ast_log(LOG_WARNING, "Got unsuported type %d\n", ast_json_typeof(jsonval));
            return -1;
    }
    return 0;
}

References ast_copy_string(), ast_debug, AST_JSON_ARRAY, ast_json_array_get(), ast_json_array_size(), ast_json_dump_string, AST_JSON_FALSE, ast_json_free(), AST_JSON_INTEGER, ast_json_integer_get(), ast_json_is_true(), AST_JSON_NULL, AST_JSON_OBJECT, ast_json_object_get(), AST_JSON_REAL, ast_json_real_get(), AST_JSON_STRING, ast_json_string_get(), AST_JSON_TRUE, ast_json_typeof(), ast_log, ast_str_to_int(), buf, d, len(), LOG_WARNING, MAX_JSON_STACK, NULL, parse_node(), result, and strsep().

Referenced by json_decode_read(), and parse_node().

unload_module()

static int unload_module ( void  )

static

Definition at line 395 of file func_json.c.

{
    int res;
 
#ifdef TEST_FRAMEWORK
    AST_TEST_UNREGISTER(test_JSON_DECODE);
#endif
    res = ast_custom_function_unregister(&json_decode_function);
 
    return res;
}

References ast_custom_function_unregister(), AST_TEST_UNREGISTER, and json_decode_function.

Variable Documentation

json_decode_function

struct ast_custom_function json_decode_function

static

Initial value:

= {
    .name = "JSON_DECODE",
    .read = json_decode_read,
}

Definition at line 298 of file func_json.c.

                                                         {
    .name = "JSON_DECODE",
    .read = json_decode_read,
};

Referenced by load_module(), and unload_module().

json_options

const struct ast_app_option json_options[128] = { [ 'c' ] = { .flag = OPT_COUNT }, }

static

Definition at line 93 of file func_json.c.

Referenced by json_decode_read().