Re: [naviserver-devel] whole lotta errors

[Zoran V. <zv...@ar...>]

On 24.08.2006, at 22:08, Stephen Deasey wrote:

>>
>> Hm... how would you (generally) check for a byte-array?
>> You can get a byte-array from object but you can't
>> (without looking into the object type which is really not
>> something that is portable) say which type of object you
>> are dealing with.
>
>
> Sure you can:
>
>   byteArrayTypePtr = Tcl_GetObjType("bytearray");
>
>   if (objPtr->typePtr == byteArrayTypePtr) {
>       /* It's a bute array... */
>   }

Yup. I know that. I'm just not sure if you
are "allowed" to peek at the type from the
outside. Normally, Tcl would provide you
with such an API, like Tcl_IsByteArrayObj(objPtr)
or such. The fact they don't obviously means
something, I believe.


>
>> I believe the main source of problem here is somebody
>> slurping the whole file and wanting to return that file
>> as-is i.e. w/o any translations. In that case, he/she
>> cound use [ns_conn encoding] to set the encoding of the
>> connection before calling ns_return. This way we can
>> strip away all the extra options from the content-returning
>> commands and request the writer to use ns_conn to set
>> the correct encoding OR to skip encoding altogether
>> (for example: ns_conn encoding binary).
>> Wouldn't that make sense?
>
>
> I was thinking more of the case where you dynamically create a binary
> object, like a 'captcha' image.  You want to ns_return it and have the
> server do the right thing without having to fiddle with a -binary
> switch.
>
> Another place where checking for a byte array might be good is the
> caching code.  when you cache an object, it first gets converted to a
> valid utf-8 rep.  When you get the object out of the cache, if you
> treat it as a byte array, evrything still works -- the conversion from
> byte array to utf-8 string and back again is non lossy. It's just non
> optimal.

That's true.

>
> As we're starting to see things like the -binary switch spread, I was
> wondering if it was, in general, a good idea to check for byte arrays
> and have things work transparently. Are there any gotchas?


I will think about that. I would like to see less of those
"-binary" things all arround as we all see that it just
confuses people. I just have a bad feeling to rely on the
object type as it can be changed (dropped) by Tcl easily
because of the "everything is a string" paradigm that Tcl
still enforces. There must be some better way to do that,
although if you ask me how, I can't give an answer to that.

Cheers
Zoran