[asterisk-users] AEL: how to check if variable is defined

[Klaus Darilion]

Hi!

I use an "if" condition in extensions.ael to check if a channel variable
is defined and if defined I add a certain header:

context toNormaleRufe {
_X. => {
if (${NUMBER}) {
SIPAddHeader(X-NUMBER: ${NUMBER});
};
...
};

This works fine, except NUMBER starts with the + sign.

I tried using quotes but
if ("${NUMBER}")
evaluates always true.

What is the suggested way to solve this?

thanks
klaus

[Philipp Kempgen]

Post by Klaus Darilion
I use an "if" condition in extensions.ael to check if a channel variable
context toNormaleRufe {
_X. => {
if (${NUMBER}) {
SIPAddHeader(X-NUMBER: ${NUMBER});
};
...
};
This works fine, except NUMBER starts with the + sign.
I tried using quotes but
if ("${NUMBER}")
evaluates always true.
What is the suggested way to solve this?

if ("${NUMBER}" != "") {
// ...
}

That doesn't tell you whether the variable is defined but in
most cases (if any) that doesn't matter anyway.

Philipp Kempgen

[Philipp Kempgen]

Post by Philipp Kempgen

Post by Klaus Darilion
I use an "if" condition in extensions.ael to check if a channel variable
context toNormaleRufe {
_X. => {
if (${NUMBER}) {
SIPAddHeader(X-NUMBER: ${NUMBER});
};
...
};
This works fine, except NUMBER starts with the + sign.
I tried using quotes but
if ("${NUMBER}")
evaluates always true.
What is the suggested way to solve this?

if ("${NUMBER}" != "") {
// ...
}
That doesn't tell you whether the variable is defined but in
most cases (if any) that doesn't matter anyway.

But I guess it wouldn't hurt to add a DEFINED() function to
Asterisk.

if (DEFINED(myvariable)) {
// ...
}


Philipp Kempgen

[Richard Lyman]

Philipp Kempgen wrote:
*snipped

Post by Philipp Kempgen
But I guess it wouldn't hurt to add a DEFINED() function to
Asterisk.
if (DEFINED(myvariable)) {
// ...
}

Isn't that what ISNULL is for?

[Philipp Kempgen]

Post by Richard Lyman

Post by Philipp Kempgen
But I guess it wouldn't hurt to add a DEFINED() function to
Asterisk.
if (DEFINED(myvariable)) {
// ...
}

Isn't that what ISNULL is for?

No. ISNULL() works on values not on variables.

But Dave Fullerton found EXISTS():
http://lists.digium.com/pipermail/asterisk-users/2008-December/224059.html


Philipp Kempgen

[Richard Lyman]

Post by Philipp Kempgen

Post by Richard Lyman

Post by Philipp Kempgen
But I guess it wouldn't hurt to add a DEFINED() function to
Asterisk.
if (DEFINED(myvariable)) {
// ...
}

Isn't that what ISNULL is for?

No. ISNULL() works on values not on variables.
http://lists.digium.com/pipermail/asterisk-users/2008-December/224059.html
Philipp Kempgen

if (${ISNULL(${CAMPAIGN})}) {
Set(CAMPAIGN=INBOUND);
};

This is how i use it.

[Klaus Darilion]

Thanks Dave, Philipp and Richard!

klaus

Post by Richard Lyman

Post by Philipp Kempgen

Post by Richard Lyman

Post by Philipp Kempgen
But I guess it wouldn't hurt to add a DEFINED() function to
Asterisk.
if (DEFINED(myvariable)) {
// ...
}

Isn't that what ISNULL is for?

No. ISNULL() works on values not on variables.
http://lists.digium.com/pipermail/asterisk-users/2008-December/224059.html
Philipp Kempgen

if (${ISNULL(${CAMPAIGN})}) {
Set(CAMPAIGN=INBOUND);
};
This is how i use it.
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[Dave Fullerton]

Post by Philipp Kempgen

Post by Philipp Kempgen

Post by Klaus Darilion
I use an "if" condition in extensions.ael to check if a channel variable
context toNormaleRufe {
_X. => {
if (${NUMBER}) {
SIPAddHeader(X-NUMBER: ${NUMBER});
};
...
};
This works fine, except NUMBER starts with the + sign.
I tried using quotes but
if ("${NUMBER}")
evaluates always true.
What is the suggested way to solve this?

if ("${NUMBER}" != "") {
// ...
}
That doesn't tell you whether the variable is defined but in
most cases (if any) that doesn't matter anyway.

But I guess it wouldn't hurt to add a DEFINED() function to
Asterisk.
if (DEFINED(myvariable)) {
// ...
}

Isn't that what EXISTS() is for?

-Dave

[Philipp Kempgen]

Post by Dave Fullerton

Post by Philipp Kempgen
But I guess it wouldn't hurt to add a DEFINED() function to
Asterisk.
if (DEFINED(myvariable)) {
// ...
}

Isn't that what EXISTS() is for?

Well, yes. :-)
I've never needed it before and it didn't come to my mind.


Philipp Kempgen