Newer
Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2021, Naveen Albert
*
* 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 Dialplan extension evaluation function
*
* \author Naveen Albert <asterisk@phreaknet.org>
*
* \ingroup functions
*/
/*** MODULEINFO
<support_level>extended</support_level>
***/
#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/utils.h"
#include "asterisk/app.h"
/*** DOCUMENTATION
<function name="EVAL_EXTEN" language="en_US">
<synopsis>
Evaluates the contents of a dialplan extension and returns it as a string.
</synopsis>
<syntax>
<parameter name="context" />
<parameter name="extensions" />
<parameter name="priority" required="true" />
</syntax>
<description>
<para>The EVAL_EXTEN function looks up a dialplan entry by context,extension,priority,
evaluates the contents of a Return statement to resolve any variable or function
references, and returns the result as a string.</para>
<para>You can use this function to create simple user-defined lookup tables or
user-defined functions.</para>
<example title="Custom dialplan functions">
[call-types]
exten => _1NNN,1,Return(internal)
exten => _NXXNXXXXXX,1,Return(external)
[udf]
exten => calleridlen,1,Return(${LEN(${CALLERID(num)})})
[default]
exten => _X!,1,Verbose(Call type ${EVAL_EXTEN(call-types,${EXTEN},1)} - ${EVAL_EXTEN(udf,calleridlen,1)})
</example>
<para>Any variables in the evaluated data will be resolved in the context of
that extension. For example, <literal>${EXTEN}</literal> would refer to the
EVAL_EXTEN extension, not the extension in the context invoking the function.
This behavior is similar to other applications, e.g. <literal>Gosub</literal>.</para>
<example title="Choosing which prompt to use">
same => n,Read(input,${EVAL_EXTEN(prompts,${CALLERID(num)},1)})
[prompts]
exten => _X!,1,Return(default)
exten => _20X,1,Return(welcome)
exten => _2XX,1,Return(${DB(promptsettings/${EXTEN})})
exten => _3XX,1,Return(${ODBC_MYFUNC(${EXTEN})})
</example>
<para>Extensions on which EVAL_EXTEN is invoked are not different from other
extensions. However, the application at that extension is not executed.
Only the application data is parsed and evaluated.</para>
<para>A limitation of this function is that the application at the specified
extension isn't actually executed, and thus unlike a Gosub, you can't pass
arguments in the EVAL_EXTEN function.</para>
</description>
<see-also>
<ref type="function">EVAL</ref>
</see-also>
</function>
***/
static int eval_exten_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
{
char *exten, *pri, *context, *parse;
int ipri;
char tmpbuf[len];
if (ast_strlen_zero(data)) {
ast_log(LOG_WARNING, "The EVAL_EXTEN function requires an extension\n");
return -1;
}
parse = ast_strdupa(data);
/* Split context,exten,pri */
context = strsep(&parse, ",");
exten = strsep(&parse, ",");
pri = strsep(&parse, ",");
if (pbx_parse_location(chan, &context, &exten, &pri, &ipri, NULL, NULL)) {
return -1;
}
if (ast_strlen_zero(exten) || ast_strlen_zero(context)) { /* only lock if we really need to */
ast_channel_lock(chan);
if (ast_strlen_zero(exten)) {
exten = ast_strdupa(ast_channel_exten(chan));
}
if (ast_strlen_zero(context)) {
context = ast_strdupa(ast_channel_context(chan));
}
ast_channel_unlock(chan);
}
if (ast_get_extension_data(tmpbuf, len, chan, context, exten, ipri)) {
return -1; /* EVAL_EXTEN failed */
}
pbx_substitute_variables_helper_full_location(chan, (chan) ? ast_channel_varshead(chan) : NULL, tmpbuf, buf, len, NULL, context, exten, ipri);
return 0;
}
static struct ast_custom_function eval_exten_function = {
.name = "EVAL_EXTEN",
.read = eval_exten_read,
};
static int unload_module(void)
{
return ast_custom_function_unregister(&eval_exten_function);
}
static int load_module(void)
{
return ast_custom_function_register(&eval_exten_function);
}
AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "Extension evaluation function");