Allow build without cups

[Luiz Angelo Daros de Luca]

Hello,

I maintain hplip for OpenWrt. Normally CUPS is too much for a router hardware. However, it can nicely handle scan jobs (SANE). Scanning code is mostly independent of CUPS, except for network discovery code in scan/sane/hpaio.c. If you want to expose a printer using a router, it is probably because that printer does not have network support (and you are using USB anyway). So, that code is not necessary.

I maintain a patch to remove CUPS requirements for SANE driver:
https://github.com/openwrt/packages/blob/master/utils/hplip/patches/020-remove_cups_dep_on_scan.patch

There is a build option for building without scanner drivers but not an option for building without CUPS drivers. I tried to add that option that myself but I got lost inside autoconf black magic. It would be much easier to someone familiar with the code.

I would like to have two new build options:
1) build only scanner driver (SANE)
2) build without CUPS (probably implies 1)

[Umesh Mahindrakar (umesh.mahindrakar)]

Hi,

You can install required module when you are installing hplip

./hplip*
Please choose the installation mode as custom

Select Driver Options as 'Discrete Drivers'

Then choose HPLIP options
for example
Enable 'Scanning Support' as 'y' so that you can install scanning support package only

Thanks,
Umesh

[Luiz Angelo Daros de Luca (luizluca)]

Thanks Umesh,

However, it is not about installing a driver but building HPLIP from sources. It is only about building requirements. As CUPS is not available as a package in OpenWrt (yet), I need to maintain a CUPS package that is used for building SANE but does nothing at all besides that. And CUPS is pretty a big project to build and cross compile to multiple CPU archs.

The patch I mentioned is already enough to have hplip sane drivers independent of CUPS at runtime. Installing cups (even some basic libraries) can require extra space that most OpenWrt users do not have. Most OpenWrt hplip users might have only 8MB of flash for both kernel and rootfs.