Finding cookie name?

[brettr]

When I reference document.cookie , there is a long string of key=value;
pairs listed. I may have 100 hundred cookies on my hard drive.
However, most only have one key=value pair. Does the document.cookie
variable combine all cookie key=value pairs?

All of the examples I've seen discuss referencing a specific cookie. I
don't see how this is done.

Cookies are usually named by the domain. If I want to reference a
specific cookie, do I need to search for my key=value pair by parsing
the document.cookie string? If I have several key=value; pairs in one
cookie, must I continue parsing for those specific key=value; pairs?

Judging by most getCookie() functions I've seen, the above seems to be
the case. I can't just call a specific cookie. I must reference
document.cookie and search for my specific key=value pairs. However, I
may be going about it the wrong way. Please clarify.

Thanks,
Brett

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[kaeli]

Re: Finding cookie name?

In article <410d797f$0$559 3$c397aba@news. newsgroups.ws>, myaccount@cygen .com
enlightened us with...[color=blue]
> Does the document.cookie
> variable combine all cookie key=value pairs?
>[/color]

Yes, it does.
[color=blue]
> All of the examples I've seen discuss referencing a specific cookie. I
> don't see how this is done.
>[/color]

There are a couple ways to do it.
[color=blue]
> Cookies are usually named by the domain.[/color]

Not always.
[color=blue]
> If I want to reference a
> specific cookie, do I need to search for my key=value pair by parsing
> the document.cookie string? If I have several key=value; pairs in one
> cookie, must I continue parsing for those specific key=value; pairs?
>[/color]

Yes.

Here's my cookie.js file if it helps you. You can get your cookie into a
string by using its name this way:
var myCk = getCookie("myCo okieName");

Watch for word-wrapping.
Note that I don't bother with setting a lot of the attributes, such as
domain, as I don't need to. You could modify this to do that.

--------------------------------------------------------------

/* jsCookies.js
This file contains cookie functions. */
/* File Functions:
1. setCookie - writes cookie
2. getCookie - gets value of cookie
3. removeCookie - deletes a cookie
4. detectCookies - checks if cookies are enabled
*/

function setCookie(cooki eName, cookieValue, expireDate)
{
/* Pass in three strings - the name of the cookie, the value, and the
expire date.
Pass in a "" empty string for expireDate to set a session cookie (no
expires date).
Pass in any other date for expire as a number of days to be added to
today's date. */

if (expireDate == "")
{
expires = "";
}
else
{
expires = new Date();
expires.setDate (expires.getDat e() + expireDate);
expires = expires.toGMTSt ring();
}
document.cookie = cookieName+"="+ cookieValue+";e xpires="+expire s;
}

function removeCookie (cookieName)
{
/* Pass in the name of the cookie as a string and it will be removed. */
expires = Now();
document.cookie = cookieName+"= ;expires="+expi res.toGMTString ();
}

function getCookie (cookieName)
{
cookieValue = ""
if (document.cooki e.indexOf(cooki eName) == -1)
{
// there is no cookie by this name for this user
return cookieValue;
}
else
{
// get the beginning index of the cookie by looking for the cookie name
cookieStart = document.cookie .indexOf(cookie Name);
// get the beginning index of the cookie value by looking for the equal
sign after the name
cookieValStart = (document.cooki e.indexOf("=", cookieStart) + 1);
// get the end index of the cookie value by looking for the semi-colon
after the value
cookieValEnd = document.cookie .indexOf(";", cookieStart);
// if no semi-colon, then use the whole length
if (cookieValEnd == -1)
{
cookieValEnd = document.cookie .length
}
// use substring to get the text between the two indices and that is
the value of the cookie
cookieValue = document.cookie .substring(cook ieValStart, cookieValEnd);
return cookieValue;
}
}

function detectCookies()
{
/* function returns true if cookies are enables, false if not */
setCookie("test ", "test", "");
tmp = getCookie("test ")
if (tmp != "test")
{
return false;
}
else
{
return true;
}
}

/* EOF */
-----------------------------------------------------------------------

--
--
~kaeli~
Never mess up an apology with an excuse.

http://www.ipwebdesign.net/wildAtHeart

http://www.ipwebdesign.net/kaelisSpace

[Thomas 'PointedEars' Lahn]

Re: Finding cookie name?

brettr wrote:[color=blue]
> When I reference document.cookie , there is a long string of key=value;
> pairs listed. I may have 100 hundred cookies on my hard drive.[/color]

You maybe want to remove some because it is likely that there are spies
among them.
[color=blue]
> However, most only have one key=value pair. Does the document.cookie
> variable combine all cookie key=value pairs?[/color]

All for one resource, when reading the property, yes.
[color=blue]
> All of the examples I've seen discuss referencing a specific cookie.[/color]

URL?
[color=blue]
> I don't see how this is done.[/color]

You could split the string value and then search for the respective key.
It then helps to split the key/value pairs again on the "=" and then
search for the key. Examples have been posted here before.
[color=blue]
> Cookies are usually named by the domain. If I want to reference a
> specific cookie, do I need to search for my key=value pair by parsing
> the document.cookie string? If I have several key=value; pairs in one
> cookie, must I continue parsing for those specific key=value; pairs?[/color]

Yes, but parsing the whole string may not be the most efficient/viable method.
[color=blue]
> Judging by most getCookie() functions I've seen,[/color]

URL(s)?
[color=blue]
> the above seems to be the case. I can't just call a specific cookie.
> I must reference document.cookie and search for my specific key=value
> pairs.[/color]

Yes, indeed.


PointedEars

[Richard Cornford]

Re: Finding cookie name?

kaeli wrote:
<snip>[color=blue]
> function getCookie (cookieName)
> {
> cookieValue = ""[/color]

There are quite a lot of global variables in this funciton that really
should be local.
[color=blue]
> if (document.cooki e.indexOf(cooki eName) == -1)[/color]
<snip>

The FAQ notes page:-

<URL: http://jibbering.com/faq/faq_notes/cookies.html >

- describes an extra safety measure necessitated by the use of content
inserting/re-writing proxies (firewalls, internet security programs and
such like) to prevent scripts from using cookies. They do this by
re-writing - document.cookie - to - document.someth ingElse - in the JS
source code. As a result the modified property accessor does not resolve
to a string (it will probably return an undefined value), and an attempt
to call - indexOf - will error as an undefined value will not
type-convert into an object.

Generally code that fails by erroring is undesirable (and potentially
embarrassing for its author if the user is seeing error messages
(proxies usually insert an - onerror - handler to suppress error
messages resulting from their actions)).

The page above proposes using a - typeof - test to verify that the
object returned from the property accessor is a string prior to calling
String object methods on it. A number of alternative safety measures
might be applied (or combined) to achieve a similar effect.

It should be possible to negate the effect of content inserting proxies
by using a bracket notation property accessor with a string value that
did not resemble "cookie":-

document["\x63o\x6Fk\x69 e"]

- (or some other escape sequence based munging of "cookie" ) in the hope
that the proxy would fail to recognise and replace that. However, if the
user is running a proxy that is attempting to prevent scripts form
reading and writing cookies then maybe subverting its actions is not a
desirable thing to be doing.

An alternative to using - typeof - to verify that - document.cookie - is
returning a string value might be to assign - new
String(document .cookie) - to a local variable. Subsequent String object
method calls would not then be error-producing, though they would still
not "work" if the property accessor resolved as an undefined value.
However, as a safety measure, explicitly converting the primitive value
returned by the property accessor into a String object would have the
advantageous side-effect of producing more efficient code. The use of a
String object method on a string primitive forces an internal
type-conversions into a String object for each method invocation, so
explicitly doing that up-front in code that uses many String object
methods would avoid the need to have it done implicitly on each method
call:-

function getCookie (cookieName){
var cookieValStart,
cookieValEnd,
cookieValue = "",
ck = new String(document .cookie);
//or - ck = new String(document["\x63o\x6Fk\x69 e"]);
if(
((cookieStart = ck.indexOf(cook ieName)) != -1)&&
((cookieValStar t = (ck.indexOf("=" , cookieStart) + 1)) != 0)
){
// get the end index of the cookie value by looking
//for the semi-colon after the value
cookieValEnd = ck.indexOf(";", cookieStart);
// if no semi-colon, then use the whole length
if (cookieValEnd == -1){
cookieValEnd = ck.length;
}
// use substring to get the text between the two
//indices and that is the value of the cookie
cookieValue = ck.substring(co okieValStart, cookieValEnd);
}
return cookieValue;
}

Richard.

[brettr]

Re: Finding cookie name?

Maybe the wording is throwing me off. I see the above code referencing
a cookiename variable being passed into somthing similar to getCookie
(cookieName). If you can't actually reference a specific cookie, why
use something called cookieName?

From what I gather, you can only reference document.cookie and parse it
for your key/value pairs.

Must the expires= be set for each key/value pair? Does this create the
cookie? document.cookie is a variable that grabs key/value pairs and
other information from .txt files and groups them all into one variable.
Ok, from that, how are you defining cookie?

Thanks,
Brett

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[Michael Winter]

Re: Finding cookie name?

On 02 Aug 2004 21:25:09 GMT, brettr <myaccount@cyge n.com> wrote:
[color=blue]
> Maybe the wording is throwing me off. I see the above code referencing
> a cookiename variable being passed into somthing similar to getCookie
> (cookieName). If you can't actually reference a specific cookie, why
> use something called cookieName?[/color]

You pass the function a string containing the name of the key/value pair
you want to retrieve.
[color=blue]
> From what I gather, you can only reference document.cookie and parse it
> for your key/value pairs.[/color]

Which is what the function does. The variable, cookieName, is the key for
the pair.
[color=blue]
> Must the expires= be set for each key/value pair?[/color]

No, it's applies to all the pairs you specify in that assignment. If you
do not specify an expiry value, the cookie becomes a session cookie. If
you do specify a date which is in the past, the included pairs are deleted.
[color=blue]
> Does this create the cookie?[/color]

Just writing the document.cookie property creates the cookie (unless the
expiry date is in the past).
[color=blue]
> document.cookie is a variable that grabs key/value pairs and
> other information from .txt files and groups them all into one variable.
> Ok, from that, how are you defining cookie?[/color]

I think you'll find it varies. Some define a cookie as a collection of
key/value pairs that exist for a specific path on a specific domain. Some
will define each individual pair as a cookie. I believe the former is the
more accurate definition, but it doesn't really matter.

Hope that helps,
Mike

--
Michael Winter
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