Re: [Vala] Soup.Buffer memory

[andrea zambon <zamby ing gmail com>]

Thank you! I added:

msg.response_body.set_accumulate (false);

Now it works correctly and the memory is stable.
The performace is good also with MemoryUse.COPY.

I do not understand the difference between EOF and CHUNKED about the
connection. I will study better.

Thank you.


2013/9/25 Evan Nemerson <evan coeus-group com>

> On Tue, 2013-09-24 at 14:24 +0200, andrea zambon wrote:
> > I am developing a service http with libsoup, but I have a memory problem.
> > When you make a request, the service memory increases during transmission
> > and decreases only after the closure of the service. Another call and
> will
> > increase again.
>
> See the API docs for Soup.MessageBody.set_accumulate:
> http://valadoc.org/libsoup-2.4/Soup.MessageBody.set_accumulate.html
>
> I have no idea if it will work for encodings other than chunked, but I
> don't see a reason why you would want to close the connection after
> every request, so why not just use chunked?
>
> > The client is in another machine and the data may be very long (2 GB).
> > I try to user Soup.MemoryUse.TAKE but I get garbage data.
> > The Soup.Buffer is not free when sending a new buffer?
>
> Using the default Soup.Buffer constructor with Soup.MemoryUse.TAKE is
> very difficult to get right.  That flag is telling libsoup:
>
>         "The caller has allocated the memory for the SoupBuffer's use;
>         libsoup will assume ownership of it and free it (with g_free())
>         when it is done with it."
>
> However, Vala isn't actually aware of the interaction between this
> parameter and libsoup's memory management.  According to the bindings,
> the argument does not transfer ownership, which means Vala will free the
> buffer for you, then it is likely to get reallocated somewhere else and
> have its contents changed.  Furthermore, when libsoup tries to free it
> your program will likely crash.
>
> If you want to transfer ownership, you should use the Soup.Buffer.take
> constructor.  By default valac will actually make a copy of the buffer
> for you, so if you want to pass along your reference (which will
> invalidate your local copy), use the (owned) keyword:
>
>         var buffer = new Soup.Buffer.take ((owned) data);
>
> I'm attaching a version of a server I wrote a while back which you may
> want to take a look at.  It uses chunked encoding for larger files,
> while smaller files are mmaped and use content length encoding.  It's
> also pretty good about doing things asynchronously when possible.
>
>
> -Evan