[Development] Qt and IoT infographic

[Jason H]

> Sent: Monday, August 28, 2017 at 11:38 AM
> From: "Thiago Macieira" <thiago.macieira at intel.com>
> To: development at qt-project.org
> Subject: Re: [Development] Qt and IoT infographic
>
> On Monday, 28 August 2017 07:01:07 PDT Jason H wrote:
> > Onto my criticisms of Qt wrt IoT:
> > 
> > 2. ZeroConf should be a standard thing. Where's Qt's support?
> 
> Right now, in KF5 (kdnssd).

And who puts/[wants to put] KDE on IoT?

 
> > 3.  IoT generally use web services, namely RESTful APIs. Where's Qt's
> > support for writing a RESTful server? 
> 
> Timur began working on an simple HTTP server. This is a controversial 
> decision, since we've long said that Qt should not be the tool for server-side 
> programs.

It shouldn't be that controversial. We're just observing MVC and pushing it from single-process to multi-process. We're not pushing Qt for the web per se, just making it an equal citizen.

> But I dispute your assertion that it should be "web services". That's why I 
> want to work on CoAP, which is much simpler than HTTP. It's still REST, but 
> not web.

Yes, and paint yourself into a corner of the internet again. While CoAP and REST are both mentioned on the web page, but it also says: "From a developer point of view, CoAP feels very much like HTTP. Obtaining a value from a sensor is not much different from obtaining a value from a Web API."

I don't see why full-on-HTTP shouldn't be supported. You (the customer) might be focused on IoT, but why restrict the other users to it as well? Just go for full-on HTTP. I'm not against CoAP, but please don't raise hurdles for those that don't need it. 

Over time the number of examples/demos where Qt consumes web services has grown dramatically, but Qt apps haven't really ever been able to provide the internet with services. Like it or not, the internet is a bus that enables modern society. And the data locked in my Qt programs can't easily contribute to that.

> > b. Remove
> > the GL dependency for QML, so that QML can function as a way to make a
> > headless HTTP server that makes it trivial to map HTTP requests to QObjects
> > or QML Elements**.
> 
> QML does not have a GL dependency. Or, for that matter, a graphical one.
> 
>  ldd $QTLIBDIR/libQt5Qml.t.so.5
>         linux-vdso.so.1 (0x00007ffe33fcf000)
>         libQt5Network.t.so.5 => /home/tjmaciei/obj/qt/qt5/qtbase/lib/
> libQt5Network.t.so.5 (0x00007fcaa427a000)
>         libQt5Core.t.so.5 => /home/tjmaciei/obj/qt/qt5/qtbase/lib/
> libQt5Core.t.so.5 (0x00007fcaa3bfd000)
>         libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fcaa39df000)
>         libdl.so.2 => /lib64/libdl.so.2 (0x00007fcaa37db000)
>         libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x00007fcaa3453000)
>         libm.so.6 => /lib64/libm.so.6 (0x00007fcaa3141000)
>         libc.so.6 => /lib64/libc.so.6 (0x00007fcaa2d9b000)
>         libz.so.1 => /lib64/libz.so.1 (0x00007fcaa2b84000)
>         libssl.so.1.0.0 => /usr/lib64/libssl.so.1.0.0 (0x00007fcaa2916000)
>         libcrypto.so.1.0.0 => /usr/lib64/libcrypto.so.1.0.0 
> (0x00007fcaa24a9000)
>         libsystemd.so.0 => /usr/lib64/libsystemd.so.0 (0x00007fcaa2215000)
>         libicui18n.so.59.1 => /usr/lib64/libicui18n.so.59.1 
> (0x00007fcaa1d88000)
>         libicuuc.so.59.1 => /usr/lib64/libicuuc.so.59.1 (0x00007fcaa19d0000)
>         libpcre2-16.so.0 => /usr/lib64/libpcre2-16.so.0 (0x00007fcaa1762000)
>         libdouble-conversion.so.1 => /usr/lib64/libdouble-conversion.so.1 
> (0x00007fcaa1551000)
>         libglib-2.0.so.0 => /usr/lib64/libglib-2.0.so.0 (0x00007fcaa123b000)
>         libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007fcaa1024000)
>         /lib64/ld-linux-x86-64.so.2 (0x00007fcaa4bd5000)
>         libresolv.so.2 => /lib64/libresolv.so.2 (0x00007fcaa0e0e000)
>         libselinux.so.1 => /lib64/libselinux.so.1 (0x00007fcaa0be7000)
>         libcap.so.2 => /usr/lib64/libcap.so.2 (0x00007fcaa09e2000)
>         librt.so.1 => /lib64/librt.so.1 (0x00007fcaa07da000)
>         liblzma.so.5 => /usr/lib64/liblzma.so.5 (0x00007fcaa059f000)
>         liblz4.so.1 => /usr/lib64/liblz4.so.1 (0x00007fcaa038b000)
>         libgcrypt.so.20 => /usr/lib64/libgcrypt.so.20 (0x00007fcaa007b000)
>         libgpg-error.so.0 => /usr/lib64/libgpg-error.so.0 (0x00007fca9fe66000)
>         libicudata.so.59.1 => /usr/lib64/libicudata.so.59.1 
> (0x00007fca9fc65000)
>         libpcre.so.1 => /usr/lib64/libpcre.so.1 (0x00007fca9f9d8000)
> 
> No, QtGui, no GL, no X11, nothing.

I seem to remember a big deal about QtQuick 2.0 requiring GL? perhaps that's just for Items? If I'm mistaken, then I am very happily mistaken!