You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@apr.apache.org by Sumeet Singh <su...@openwave.com> on 2004/04/21 18:11:24 UTC
[PATCH] RFC: Allow modification/deletion of specific headers in apr_table_t
Hi,
In my use-case I am dealing with multiple headers with the same key
(e.g. Cookie), and need to modify or remove a specific header based on
its key and value (e.g. remove a certain cookie header while leaving the
rest in). There is no api in apr_tables that would allow me to remove a
given header instance. apr_table_unset will remove all cookies. And I
can't have my code remove a header from the apr_array_table_t array
because that will render the internal hash index incorrect. Secondly,
eventhough I can modify the value of a specific header by iterating over
the apr_array_header_t, that would be inefficient because I wouldn't be
able to use the internal index_first and index_last values. Therefore I
have written three functions (patch files attached) and am hoping that
the powers-that-be
will be willing to review and roll them into the APR codeline.
1) apr_table_set_one (apr_table_t *t, const char *key, const char
*oldVal, const char *newVal)
replaces value of header "key" and value "oldVal" with value
"newVal". If "oldVal" is null, then the first occurance of the header is
replaces (this is an optimization for situations where we know that only
one header exists and don't care about its current value). If the
header is not found, then it behaves like apr_table_add.
2) apr_table_setn_one(apr_table_t *t, const char *key, const char
*oldVal, const char *newVal)
Same as apr_table_set_one exept that it doesn't make a copy of key
and newVal.
3) apr_table_unset_one(apr_table_t *t, const char *key, const char
*oldVal, const char *newVal)
Unsets header "key" with value "oldVal". If "oldVal" is null, then
the first instance of the header (only) is unset (this is an
optimization for situations where we know that only one header exists
and don't care about its current value).
-regards,
sumeet
Re: [PATCH] RFC: Allow modification/deletion of specific headers
in apr_table_t
Posted by Geoffrey Young <ge...@modperlcookbook.org>.
Sumeet Singh wrote:
> Brian,
> If you ask me, I can write the new functions (i.e. the apr_table_do -
> type functions you described) and submit a patch for review. Let me know
I have often wanted an apr_table_do-esque interface that allowed for
modification of table entries as suggested, so that sounds good to me.
--Geoff
Re: [PATCH] RFC: Allow modification/deletion of specific headers
in apr_table_t
Posted by Sumeet Singh <su...@openwave.com>.
Brian,
If you ask me, I can write the new functions (i.e. the apr_table_do
- type functions you described) and submit a patch for review. Let me
know ...
-sumeet
Sumeet Singh wrote:
> Brian Pane wrote:
>
>>
>> On Apr 21, 2004, at 9:11 AM, Sumeet Singh wrote:
>>
>>> Hi,
>>> In my use-case I am dealing with multiple headers with the same
>>> key (e.g. Cookie), and need to modify or remove a specific header
>>> based on its key and value (e.g. remove a certain cookie header
>>> while leaving the rest in). There is no api in apr_tables that would
>>> allow me to remove a given header instance. apr_table_unset will
>>> remove all cookies. And I can't have my code remove a header from
>>> the apr_array_table_t array because that will render the internal
>>> hash index incorrect. Secondly, eventhough I can modify the value of
>>> a specific header by iterating over the apr_array_header_t, that
>>> would be inefficient because I wouldn't be able to use the internal
>>> index_first and index_last values. Therefore I have written three
>>> functions (patch files attached) and am hoping that the
>>> powers-that-be will be willing to review and roll them into the APR
>>> codeline.
>>>
>>> 1) apr_table_set_one (apr_table_t *t, const char *key, const char
>>> *oldVal, const char *newVal)
>>> replaces value of header "key" and value "oldVal" with value
>>> "newVal". If "oldVal" is null, then the first occurance of the
>>> header is replaces (this is an optimization for situations where we
>>> know that only one header exists and don't care about its current
>>> value). If the header is not found, then it behaves like apr_table_add.
>>
>>
>>
>> I finally got a chance to read through the patch. The code makes
>> sense, but I
>> have a question: will apr_table_set_one and apr_table_unset_one provide
>> all the functionality you need?
>>
>> Using Cookie and Set-Cookie headers as an example, it seems like an
>> exact
>> match on the oldVal wouldn't be sufficient. If your response headers
>> include
>> something like this:
>> Content-Type; text/html
>> Set-Cookie: userID=1; max-age=86400; domain=.example.com
>> Cache-Control: private
>> Set-Cookie: sessionID=54321; max-age=1800; domain=.example.com
>> and you want to change or remove the "userID" cookie, it's a lot easier
>> to do a prefix match on "userID=" than on the entire value of that table
>> entry. (If that table entry was set by some other module, we may not
>> know what the full value of that entry is.)
>>
> That's a good point.
>
>> In the general case, an application might need to:
>> 1. iterate through all the elements in a table that match a given key,
>> 2. selectively modify the value of one or more of the matching
>> elements, or delete one or more of the matching elements,
>> 3. and optionally stop iterating based on some application-defined
>> criteria.
>>
> Agreed.
>
>> This sounds a lot like apr_table_do, except that apr_table_do
>> doesn't allow modification of the table elements.
>>
>> If there were a variant of apr_table_do that allowed modification
>> of the value (but not the key) of visited elements, and the deletion
>> of visited elements, would that work for your application?
>>
> Yes that should suffice. Thanks.
>
> -sumeet
>
>> Brian
>>
>
>
Re: [PATCH] RFC: Allow modification/deletion of specific headers
in apr_table_t
Posted by Sumeet Singh <su...@openwave.com>.
Brian Pane wrote:
>
> On Apr 21, 2004, at 9:11 AM, Sumeet Singh wrote:
>
>> Hi,
>> In my use-case I am dealing with multiple headers with the same key
>> (e.g. Cookie), and need to modify or remove a specific header based
>> on its key and value (e.g. remove a certain cookie header while
>> leaving the rest in). There is no api in apr_tables that would allow
>> me to remove a given header instance. apr_table_unset will remove all
>> cookies. And I can't have my code remove a header from the
>> apr_array_table_t array because that will render the internal hash
>> index incorrect. Secondly, eventhough I can modify the value of a
>> specific header by iterating over the apr_array_header_t, that would
>> be inefficient because I wouldn't be able to use the internal
>> index_first and index_last values. Therefore I have written three
>> functions (patch files attached) and am hoping that the
>> powers-that-be will be willing to review and roll them into the APR
>> codeline.
>>
>> 1) apr_table_set_one (apr_table_t *t, const char *key, const char
>> *oldVal, const char *newVal)
>> replaces value of header "key" and value "oldVal" with value
>> "newVal". If "oldVal" is null, then the first occurance of the header
>> is replaces (this is an optimization for situations where we know
>> that only one header exists and don't care about its current value).
>> If the header is not found, then it behaves like apr_table_add.
>
>
> I finally got a chance to read through the patch. The code makes
> sense, but I
> have a question: will apr_table_set_one and apr_table_unset_one provide
> all the functionality you need?
>
> Using Cookie and Set-Cookie headers as an example, it seems like an
> exact
> match on the oldVal wouldn't be sufficient. If your response headers
> include
> something like this:
> Content-Type; text/html
> Set-Cookie: userID=1; max-age=86400; domain=.example.com
> Cache-Control: private
> Set-Cookie: sessionID=54321; max-age=1800; domain=.example.com
> and you want to change or remove the "userID" cookie, it's a lot easier
> to do a prefix match on "userID=" than on the entire value of that table
> entry. (If that table entry was set by some other module, we may not
> know what the full value of that entry is.)
>
That's a good point.
> In the general case, an application might need to:
> 1. iterate through all the elements in a table that match a given key,
> 2. selectively modify the value of one or more of the matching
> elements, or delete one or more of the matching elements,
> 3. and optionally stop iterating based on some application-defined
> criteria.
>
Agreed.
> This sounds a lot like apr_table_do, except that apr_table_do
> doesn't allow modification of the table elements.
>
> If there were a variant of apr_table_do that allowed modification
> of the value (but not the key) of visited elements, and the deletion
> of visited elements, would that work for your application?
>
Yes that should suffice. Thanks.
-sumeet
> Brian
>
Re: [PATCH] RFC: Allow modification/deletion of specific headers in apr_table_t
Posted by Brian Pane <br...@apache.org>.
On Apr 21, 2004, at 9:11 AM, Sumeet Singh wrote:
> Hi,
> In my use-case I am dealing with multiple headers with the same key
> (e.g. Cookie), and need to modify or remove a specific header based on
> its key and value (e.g. remove a certain cookie header while leaving
> the rest in). There is no api in apr_tables that would allow me to
> remove a given header instance. apr_table_unset will remove all
> cookies. And I can't have my code remove a header from the
> apr_array_table_t array because that will render the internal hash
> index incorrect. Secondly, eventhough I can modify the value of a
> specific header by iterating over the apr_array_header_t, that would
> be inefficient because I wouldn't be able to use the internal
> index_first and index_last values. Therefore I have written three
> functions (patch files attached) and am hoping that the powers-that-be
> will be willing to review and roll them into the APR codeline.
>
> 1) apr_table_set_one (apr_table_t *t, const char *key, const char
> *oldVal, const char *newVal)
> replaces value of header "key" and value "oldVal" with value
> "newVal". If "oldVal" is null, then the first occurance of the header
> is replaces (this is an optimization for situations where we know that
> only one header exists and don't care about its current value). If the
> header is not found, then it behaves like apr_table_add.
I finally got a chance to read through the patch. The code makes
sense, but I
have a question: will apr_table_set_one and apr_table_unset_one provide
all the functionality you need?
Using Cookie and Set-Cookie headers as an example, it seems like an
exact
match on the oldVal wouldn't be sufficient. If your response headers
include
something like this:
Content-Type; text/html
Set-Cookie: userID=1; max-age=86400; domain=.example.com
Cache-Control: private
Set-Cookie: sessionID=54321; max-age=1800; domain=.example.com
and you want to change or remove the "userID" cookie, it's a lot easier
to do a prefix match on "userID=" than on the entire value of that table
entry. (If that table entry was set by some other module, we may not
know what the full value of that entry is.)
In the general case, an application might need to:
1. iterate through all the elements in a table that match a given key,
2. selectively modify the value of one or more of the matching
elements, or delete one or more of the matching elements,
3. and optionally stop iterating based on some application-defined
criteria.
This sounds a lot like apr_table_do, except that apr_table_do
doesn't allow modification of the table elements.
If there were a variant of apr_table_do that allowed modification
of the value (but not the key) of visited elements, and the deletion
of visited elements, would that work for your application?
Brian
Re: [PATCH] RFC: Allow modification/deletion of specific headers in apr_table_t
Posted by Brian Pane <br...@apache.org>.
On Apr 21, 2004, at 9:11 AM, Sumeet Singh wrote:
> Hi,
> In my use-case I am dealing with multiple headers with the same key
> (e.g. Cookie), and need to modify or remove a specific header based on
> its key and value (e.g. remove a certain cookie header while leaving
> the rest in). There is no api in apr_tables that would allow me to
> remove a given header instance. apr_table_unset will remove all
> cookies. And I can't have my code remove a header from the
> apr_array_table_t array because that will render the internal hash
> index incorrect. Secondly, eventhough I can modify the value of a
> specific header by iterating over the apr_array_header_t, that would
> be inefficient because I wouldn't be able to use the internal
> index_first and index_last values. Therefore I have written three
> functions (patch files attached) and am hoping that the powers-that-be
> will be willing to review and roll them into the APR codeline.
>
> 1) apr_table_set_one (apr_table_t *t, const char *key, const char
> *oldVal, const char *newVal)
> replaces value of header "key" and value "oldVal" with value
> "newVal". If "oldVal" is null, then the first occurance of the header
> is replaces (this is an optimization for situations where we know that
> only one header exists and don't care about its current value). If the
> header is not found, then it behaves like apr_table_add.
>
> 2) apr_table_setn_one(apr_table_t *t, const char *key, const char
> *oldVal, const char *newVal)
> Same as apr_table_set_one exept that it doesn't make a copy of key
> and newVal.
>
> 3) apr_table_unset_one(apr_table_t *t, const char *key, const char
> *oldVal, const char *newVal)
> Unsets header "key" with value "oldVal". If "oldVal" is null, then
> the first instance of the header (only) is unset (this is an
> optimization for situations where we know that only one header exists
> and don't care about its current value).
+1 for the concept. I'm willing to review and commit the code if
nobody else has any objections in the next couple of days.
-Brian