[Asterisk-code-review] func_json: Enhance parsing capabilities of JSON_DECODE (asterisk[master])
N A
asteriskteam at digium.com
Sat Feb 12 16:03:25 CST 2022
N A has uploaded this change for review. ( https://gerrit.asterisk.org/c/asterisk/+/18012 )
Change subject: func_json: Enhance parsing capabilities of JSON_DECODE
......................................................................
func_json: Enhance parsing capabilities of JSON_DECODE
Adds support for arrays to JSON_DECODE by allowing the
user to print out entire arrays or index a particular
key or print the number of keys in a JSON array.
Additionally, adds support for recursively iterating a
JSON tree in a single function call, making it easier
to parse JSON results with multiple levels.
Also fixes a bug with the unit tests causing an empty
string to be printed instead of the actual test result.
ASTERISK-29913 #close
Change-Id: I603940b216a3911b498fc6583b18934011ef5d5b
---
A doc/CHANGES-staging/func_json_additions.txt
M funcs/func_json.c
2 files changed, 157 insertions(+), 42 deletions(-)
git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/12/18012/1
diff --git a/doc/CHANGES-staging/func_json_additions.txt b/doc/CHANGES-staging/func_json_additions.txt
new file mode 100644
index 0000000..963f0b1
--- /dev/null
+++ b/doc/CHANGES-staging/func_json_additions.txt
@@ -0,0 +1,5 @@
+Subject: func_json
+
+Additional parsing capabilities have been added to the
+JSON_DECODE function, including support for arrays
+and recursive indexing.
diff --git a/funcs/func_json.c b/funcs/func_json.c
index a48b85c..fd7ba69 100644
--- a/funcs/func_json.c
+++ b/funcs/func_json.c
@@ -49,6 +49,21 @@
</parameter>
<parameter name="item" required="true">
<para>The name of the key whose value to return.</para>
+ <para>Multiple keys can be listed separated by a hierarchy delimeter, which will recursively index into a nested JSON string to retrieve a specific subkey's value.</para>
+ </parameter>
+ <parameter name="separator" required="false">
+ <para>A single character that delimits a key hierarchy for nested indexing. Default is a period (.)</para>
+ <para>This value should not appear in the key or hierarchy of keys itself, except to delimit the hierarchy of keys.</para>
+ </parameter>
+ <parameter name="options" required="no">
+ <optionlist>
+ <option name="c">
+ <para>For keys that reference a JSON array, return
+ the number of items in the array.</para>
+ <para>This option has no effect on any other type
+ of value.</para>
+ </option>
+ </optionlist>
</parameter>
</syntax>
<description>
@@ -64,19 +79,40 @@
AST_THREADSTORAGE(result_buf);
+enum say_option_flags {
+ OPT_COUNT = (1 << 0),
+};
+
+AST_APP_OPTIONS(json_options, {
+ AST_APP_OPTION('c', OPT_COUNT),
+});
+
static int json_decode_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
{
+ int count = 0;
+ struct ast_flags flags = {0};
struct ast_json *json, *jsonval;
+ char *nestchar = "."; /* default delimeter for nesting key indexing is . */
+
AST_DECLARE_APP_ARGS(args,
AST_APP_ARG(varname);
AST_APP_ARG(key);
+ AST_APP_ARG(nestchar);
+ AST_APP_ARG(options);
);
- char *varsubst, *result2;
+ char *varsubst, *result2, *key, *currentkey, *previouskey;
const char *result = NULL;
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;
@@ -85,6 +121,15 @@
ast_log(LOG_WARNING, "%s requires a key\n", cmd);
return -1;
}
+ key = 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 ${} and null terminator */
if (!varsubst) {
@@ -93,43 +138,93 @@
}
sprintf(varsubst, "${%s}", args.varname); /* safe, because of the above allocation */
ast_str_substitute_variables(&str, 0, chan, varsubst);
- 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 */
- }
- ast_debug(1, "Parsing JSON: %s\n", ast_str_buffer(str));
+ ast_debug(1, "Parsing JSON using nesting delimeter '%s'\n", nestchar);
- json = ast_json_load_str(str, NULL);
+ /* allow for multiple key nesting */
+ while ((currentkey = strsep(&key, 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 */
+ }
+ ast_debug(1, "Parsing JSON: %s\n", ast_str_buffer(str));
- if (!json) {
- ast_log(LOG_WARNING, "Failed to parse as JSON: %s\n", ast_str_buffer(str));
- return -1;
- }
+ json = ast_json_load_str(str, NULL);
- jsonval = ast_json_object_get(json, args.key);
- if (!jsonval) { /* no error or warning should be thrown */
- ast_debug(1, "Could not find key '%s' in parsed JSON\n", args.key);
+ if (!json) {
+ ast_log(LOG_WARNING, "Failed to parse as JSON: %s\n", ast_str_buffer(str));
+ return -1;
+ }
+
+ jsonval = ast_json_object_get(json, currentkey);
+ if (!jsonval) { /* no error or warning should be thrown */
+ ast_debug(1, "Could not find key '%s' in parsed JSON\n", currentkey);
+ ast_json_free(json);
+ return -1;
+ }
+ snprintf(buf, len, "%s", ""); /* clear the buffer from previous round if necessary */
+ switch(ast_json_typeof(jsonval)) {
+ char *buf2;
+ unsigned long int size;
+ int r, buflen2;
+ case AST_JSON_STRING:
+ result = ast_json_string_get(jsonval);
+ snprintf(buf, len, "%s", result);
+ break;
+ case AST_JSON_INTEGER:
+ r = ast_json_integer_get(jsonval);
+ snprintf(buf, len, "%d", r); /* the snprintf below is mutually exclusive with this one */
+ break;
+ case AST_JSON_ARRAY:
+ 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\n", size);
+ 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);
+ } else {
+ ast_debug(1, "No key on which to index in the array, so dumping '%s' array\n", previouskey);
+ buf2 = buf;
+ buflen2 = len;
+ snprintf(buf2, buflen2, "%s", "[");
+ buf2++;
+ buflen2--;
+ for (r = 0; r < size; r++) {
+ int rlen;
+ snprintf(buf2, buflen2, "\"%s\",", ast_json_string_get(ast_json_array_get(jsonval, r)));
+ rlen = strlen(ast_json_string_get(ast_json_array_get(jsonval, r)));
+ buf2 += rlen + 3; /* add 3 for the surrounding quotes and trailing comma */
+ buflen2 -= (buflen2 + 3);
+ }
+ /* no trailing comma after last item */
+ buf2--;
+ buflen2++;
+ snprintf(buf2, buflen2, "%s", "]");
+ }
+ break;
+ } 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 {
+ result = ast_json_string_get(ast_json_array_get(jsonval, r));
+ if (result) {
+ ast_debug(1, "Index %d in array contains '%s'\n", r, result);
+ snprintf(buf, len, "%s", result);
+ }
+ }
+ break;
+ default:
+ result2 = ast_json_dump_string(jsonval);
+ snprintf(buf, len, "%s", result2);
+ ast_json_free(result2);
+ break;
+ }
ast_json_free(json);
- return -1;
+ ast_str_set(&str, 0, "%s", buf); /* recurse on this node if necessary */
}
- switch(ast_json_typeof(jsonval)) {
- int r;
- case AST_JSON_STRING:
- result = ast_json_string_get(jsonval);
- snprintf(buf, len, "%s", result);
- break;
- case AST_JSON_INTEGER:
- r = ast_json_integer_get(jsonval);
- snprintf(buf, len, "%d", r); /* the snprintf below is mutually exclusive with this one */
- break;
- default:
- result2 = ast_json_dump_string(jsonval);
- snprintf(buf, len, "%s", result2);
- ast_json_free(result2);
- break;
- }
- ast_json_free(json);
return 0;
}
@@ -146,12 +241,23 @@
struct ast_channel *chan; /* dummy channel */
struct ast_str *str; /* fancy string for holding comparing value */
- const char *test_strings[][5] = {
- {"{\"city\": \"Anytown\", \"state\": \"USA\"}", "city", "Anytown"},
- {"{\"city\": \"Anytown\", \"state\": \"USA\"}", "state", "USA"},
- {"{\"city\": \"Anytown\", \"state\": \"USA\"}", "blah", ""},
- {"{\"key1\": \"123\", \"key2\": \"456\"}", "key1", "123"},
- {"{\"key1\": 123, \"key2\": 456}", "key1", "123"},
+ const char *test_strings[][6] = {
+ {"{\"city\": \"Anytown\", \"state\": \"USA\"}", "", "city", "Anytown"},
+ {"{\"city\": \"Anytown\", \"state\": \"USA\"}", "", "state", "USA"},
+ {"{\"city\": \"Anytown\", \"state\": \"USA\"}", "", "blah", ""},
+ {"{\"key1\": \"123\", \"key2\": \"456\"}", "", "key1", "123"},
+ {"{\"key1\": 123, \"key2\": 456}", "", "key1", "123"},
+ {"{ \"path\": { \"to\": { \"elem\": \"someVar\" } } }", "/", "path/to/elem", "someVar"},
+ {"{ \"path\": { \"to\": { \"elem\": \"someVar\" } } }", "", "path.to.elem2", ""},
+ {"{ \"path\": { \"to\": { \"arr\": [ \"item0\", \"item1\" ] } } }", ",c", "path.to.arr", "2"}, /* test count */
+ {"{ \"path\": { \"to\": { \"arr\": [ \"item0\", \"item1\" ] } } }", "", "path.to.arr", "[\"item0\",\"item1\"]"},
+ {"{ \"path\": { \"to\": { \"arr\": [ \"item0\", \"item1\" ] } } }", ".", "path.to.arr.1", "item1"},
+ {"{ \"path\": { \"to\": { \"arr\": [ \"item0\", \"item1\" ] } } }", "/", "path/to/arr", "[\"item0\",\"item1\"]"},
+ {"{ \"path\": { \"to\": { \"arr\": [ \"item0\", \"item1\" ] } } }", "/", "path/to/arr/1", "item1"},
+ {"{ \"path\": { \"to\": { \"arr\": [ \"item0\", \"item1\" ] } } }", "/", "path/to/arr/2", ""}, /* nonexistent index */
+ {"{ \"path\": { \"to\": { \"arr\": [ \"item0\", \"item1\" ] } } }", "/", "path/to/arr/-1", ""}, /* bogus index */
+ {"{ \"path\": { \"to\": { \"arr\": [ \"item0\", \"item1\" ] } } }", "/", "path/to/arr/test", ""}, /* bogus index */
+ {"{ \"path\": { \"to\": { \"arr\": [ \"item0\", \"item1\" ] } } }", "", "path.to.arr.test.test2.subkey", ""}, /* bogus index */
};
switch (cmd) {
@@ -177,7 +283,7 @@
}
for (i = 0; i < ARRAY_LEN(test_strings); i++) {
- char tmp[512], tmp2[512] = "";
+ char tmp[512];
struct ast_var_t *var = ast_var_assign("test_string", test_strings[i][0]);
if (!var) {
@@ -189,11 +295,11 @@
AST_LIST_INSERT_HEAD(ast_channel_varshead(chan), var, entries);
- snprintf(tmp, sizeof(tmp), "${JSON_DECODE(%s,%s)}", "test_string", test_strings[i][1]);
+ snprintf(tmp, sizeof(tmp), "${JSON_DECODE(%s,%s,%s)}", "test_string", test_strings[i][2], test_strings[i][1]);
ast_str_substitute_variables(&str, 0, chan, tmp);
- if (strcmp(test_strings[i][2], ast_str_buffer(str))) {
- ast_test_status_update(test, "Format string '%s' substituted to '%s'. Expected '%s'.\n", test_strings[i][0], tmp2, test_strings[i][2]);
+ if (strcmp(test_strings[i][3], ast_str_buffer(str))) {
+ ast_test_status_update(test, "Format string '%s' substituted to '%s'. Expected '%s'.\n", test_strings[i][0], ast_str_buffer(str), test_strings[i][3]);
res = AST_TEST_FAIL;
}
}
@@ -209,7 +315,9 @@
{
int res;
+#ifdef TEST_FRAMEWORK
AST_TEST_UNREGISTER(test_JSON_DECODE);
+#endif
res = ast_custom_function_unregister(&json_decode_function);
return res;
@@ -219,7 +327,9 @@
{
int res;
+#ifdef TEST_FRAMEWORK
AST_TEST_REGISTER(test_JSON_DECODE);
+#endif
res = ast_custom_function_register(&json_decode_function);
return res;
--
To view, visit https://gerrit.asterisk.org/c/asterisk/+/18012
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Gerrit-Project: asterisk
Gerrit-Branch: master
Gerrit-Change-Id: I603940b216a3911b498fc6583b18934011ef5d5b
Gerrit-Change-Number: 18012
Gerrit-PatchSet: 1
Gerrit-Owner: N A <mail at interlinked.x10host.com>
Gerrit-MessageType: newchange
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