name: rssreader-app
version: 1.0
summary: A snap app from Ubuntu phone app
description: This is an exmaple showing how to convert a Ubuntu phone app to a desktop snap app
confinement: strictapps:rssreader:command: desktop-launch $SNAP/lib/x86_64-linux-gnu/bin/rssreaderplugs: [network,network-bind,network-manager,home,unity7,opengl]parts:rssreader:source: src/plugin: qmakeqt-version: qt5build-packages:- cmake- gettext- intltool- ubuntu-touch-sounds- suru-icon-theme- qml-module-qttest- qml-module-qtsysteminfo- qml-module-qt-labs-settings- qtdeclarative5-u1db1.0- qtdeclarative5-qtmultimedia-plugin- qtdeclarative5-qtpositioning-plugin- qtdeclarative5-ubuntu-content1- qt5-default- qtbase5-dev- qtdeclarative5-dev- qtdeclarative5-dev-tools- qtdeclarative5-folderlistmodel-plugin- qtdeclarative5-ubuntu-ui-toolkit-plugin- xvfbstage-packages:- ubuntu-sdk-libs- qtubuntu-desktop- qml-module-qtsysteminfo- ubuntu-defaults-zh-cnsnap:- -usr/share/doc- -usr/includeafter: [desktop/qt5]

$ snap interfaces

来显示我们应用所有的plug：

liuxg@liuxg:~/snappy/desktop/rssreader$ snap interfaces
Slot                 Plug
:camera              -
:cups-control        -
:firewall-control    -
:gsettings           -
:home                rssreader-app
:locale-control      -
:log-observe         snappy-debug
:modem-manager       -
:mount-observe       -
:network             rssreader-app
:network-bind        rssreader-app
:network-control     -
:network-manager     -
:network-observe     -
:opengl              rssreader-app
:optical-drive       -
:ppp                 -
:pulseaudio          -
:snapd-control       -
:system-observe      -
:timeserver-control  -
:timezone-control    -
:unity7              rssreader-app
:x11                 -
-                    rssreader-app:network-manager

-                    rssreader-app:network-manager

这是什么意思呢？我们来重新查看连接interfaces，在那个页面里虽然目前还没有network-manager的介绍，但是我们可以看到诸如：

network-controlCan configure networking. This is restricted because it gives wide, privileged access to networking and should only be used with trusted apps.Usage: reserved Auto-Connect: no

我们需要注意的是最下面的一句话：Auto-Connect: no．也就是说自动连接不存在．对于我们的networrk-manager的情况也是一样的．我们需要手动来连接．那么我们该如何来手动连接呢？

liuxg@liuxg:~$ snap --help
Usage:snap [OPTIONS] <command>The snap tool interacts with the snapd daemon to control the snappy software platform.Application Options:--version  print the version and exitHelp Options:-h, --help     Show this help messageAvailable commands:abort        Abort a pending changeack          Adds an assertion to the systemchange       List a change's taskschanges      List system changesconnect      Connects a plug to a slotcreate-user  Creates a local system userdisconnect   Disconnects a plug from a slotfind         Finds packages to installhelp         Helpinstall      Install a snap to the systeminterfaces   Lists interfaces in the systemknown        Shows known assertions of the provided typelist         List installed snapslogin        Authenticates on snapd and the storelogout       Log out of the storerefresh      Refresh a snap in the systemremove       Remove a snap from the systemrun          Run the given snap commandtry          Try an unpacked snap in the system

我们通过上面的命令，我们可以知道snap有一个叫做connect的命令．进一步：

liuxg@liuxg:~$ snap connect -h
Usage:snap [OPTIONS] connect <snap>:<plug> <snap>:<slot>The connect command connects a plug to a slot.
It may be called in the following ways:$ snap connect <snap>:<plug> <snap>:<slot>Connects the specific plug to the specific slot.$ snap connect <snap>:<plug> <snap>Connects the specific plug to the only slot in the provided snap that matches
the connected interface. If more than one potential slot exists, the command
fails.$ snap connect <plug> <snap>[:<slot>]Without a name for the snap offering the plug, the plug name is looked at in
the gadget snap, the kernel snap, and then the os snap, in that order. The
first of these snaps that has a matching plug name is used and the command
proceeds as above.Application Options:--version            print the version and exitHelp Options:-h, --help               Show this help message

显然我们需要使用如下的命令来完成我们的connect工作：

$ snap connect <plug> <snap>[:<slot>]

针对我们的情况，我们使用如下的命令：

$ sudo snap connect rssreader-app:network-manager ubuntu-core:network-manager

当我们打入上面的命令后，我们重新来看我们的snap interfaces:

liuxg@liuxg:~$ snap interfaces
Slot                 Plug
:camera              -
:cups-control        -
:firewall-control    -
:gsettings           -
:home                rssreader-app
:locale-control      -
:log-observe         snappy-debug
:modem-manager       -
:mount-observe       -
:network             rssreader-app
:network-bind        rssreader-app
:network-control     -
:network-manager     rssreader-app
:network-observe     -
:opengl              rssreader-app
:optical-drive       -
:ppp                 -
:pulseaudio          -
:snapd-control       -
:system-observe      -
:timeserver-control  -
:timezone-control    -
:unity7              rssreader-app
:x11                 -

liuxg@liuxg:~/snappy/desktop/rssreader$ rssreader-app.rssreader (process:9770): Gtk-WARNING **: Locale not supported by C library.Using the fallback 'C' locale.
Gtk-Message: Failed to load module "overlay-scrollbar"
Gtk-Message: Failed to load module "gail"
Gtk-Message: Failed to load module "atk-bridge"
Gtk-Message: Failed to load module "unity-gtk-module"
Gtk-Message: Failed to load module "canberra-gtk-module"
qml: columns: 1
qml: columns: 2
qml: currentIndex: 0
qml: index: 0
qml: adding page...
qml: sourcePage must be added to the view to add new page.
qml: going to add the page
qml: it is added: 958
XmbTextListToTextProperty result code -2
XmbTextListToTextProperty result code -2

显然我们的应用再也没有相应的错误提示了．

６）为我们的应用加上应用图标

liuxg@liuxg:~/snappy/desktop/rssreader/setup/gui$ ls -l
total 100
-rw-rw-r-- 1 liuxg liuxg   325 7月  14 13:18 rssreader.desktop
-rw-rw-r-- 1 liuxg liuxg 91353 7月  14 11:50 rssreader.png

加入这两个文件后的项目结构为：

liuxg@liuxg:~/snappy/desktop/rssreader$ tree -L 3
.
├── setup
│   └── gui
│       ├── rssreader.desktop
│       └── rssreader.png
├── snapcraft.yaml
└── src├── manifest.json.in├── po│   └── rssreader.liu-xiao-guo.pot├── rssreader│   ├── components│   ├── main.cpp│   ├── Main.qml│   ├── rssreader.apparmor│   ├── rssreader.desktop│   ├── rssreader.png│   ├── rssreader.pro│   ├── rssreader.qrc│   └── tests└── rssreader.pro

有了上面的两个文件，我们再次重新打包并安装我们的snap应用．安装完后，在我们的dash里：

liuxg@liuxg:~$ snap --help
Usage:snap [OPTIONS] <command>The snap tool interacts with the snapd daemon to control the snappy software platform.Application Options:--version  print the version and exitHelp Options:-h, --help     Show this help messageAvailable commands:abort        Abort a pending changeack          Adds an assertion to the systemchange       List a change's taskschanges      List system changesconnect      Connects a plug to a slotcreate-user  Creates a local system userdisconnect   Disconnects a plug from a slotfind         Finds packages to installhelp         Helpinstall      Install a snap to the systeminterfaces   Lists interfaces in the systemknown        Shows known assertions of the provided typelist         List installed snapslogin        Authenticates on snapd and the storelogout       Log out of the storerefresh      Refresh a snap in the systemremove       Remove a snap from the systemrun          Run the given snap commandtry          Try an unpacked snap in the system

我们在上面的命令中，发现一个叫做try的命令．在我们运行完snapcraft命令后，snapcraft会帮我们生产相应的.snap文件．同时它也帮我们生产如下的目录：

liuxg@liuxg:~/snappy/desktop/rssreader$ ls -d */
parts/  prime/  setup/  src/  stage/

这其中有一个叫做prime的目录，其实它的里面就是我们安装snap后的文件．我们可以使用如下的方法：

$ sudo snap try prime/

通过上面的命令我们就可以把我们的snap安装到系统中．重新展示我们的snap安装目录：

liuxg@liuxg:/var/lib/snapd/snaps$ ls -al
total 287200
drwxr-xr-x 2 root root      4096 7月  15 11:13 .
drwxr-xr-x 7 root root      4096 7月  15 11:13 ..
-rw------- 1 root root  98439168 7月  14 13:10 mpv_x1.snap
-rw------- 1 root root 127705088 7月  14 17:30 photos-app_x1.snap
lrwxrwxrwx 1 root root        42 7月  15 11:13 rssreader-app_x1.snap -> /home/liuxg/snappy/desktop/rssreader/prime
-rw------- 1 root root     16384 7月  13 15:53 snappy-debug_22.snap
-rw------- 1 root root  67899392 7月  13 12:26 ubuntu-core_122.snap

我们看见其实就是一个软链接．通过这样的方法，我们很快地部署了我们的snap应用．同时避免每次安装时各个不同版本之间带来的不同安装．snap包实际上是一个使用squashfs打包而生产的．通过snap try，我们不需要创建一个squashfs文件．他的另外一个好处是我们可以随时修改这个snap的应用的内容，这是因为它本身是read-write的．我们可以甚至加上--devmode选项来取消应用对安全的限制．

８）利用devmode免除在开发时的安全考虑

snapcraft.yaml

name: rssreader-app
version: 1.0
summary: A snap app from Ubuntu phone app
description: This is an exmaple showing how to convert a Ubuntu phone app to a desktop snap app
confinement: devmodeapps:rssreader:command: desktop-launch $SNAP/lib/x86_64-linux-gnu/bin/rssreaderplugs: [network,network-bind,network-manager,home,unity7,opengl]parts:rssreader:source: src/plugin: qmakeqt-version: qt5build-packages:- cmake- gettext- intltool- ubuntu-touch-sounds- suru-icon-theme- qml-module-qttest- qml-module-qtsysteminfo- qml-module-qt-labs-settings- qtdeclarative5-u1db1.0- qtdeclarative5-qtmultimedia-plugin- qtdeclarative5-qtpositioning-plugin- qtdeclarative5-ubuntu-content1- qt5-default- qtbase5-dev- qtdeclarative5-dev- qtdeclarative5-dev-tools- qtdeclarative5-folderlistmodel-plugin- qtdeclarative5-ubuntu-ui-toolkit-plugin- xvfbstage-packages:- ubuntu-sdk-libs- qtubuntu-desktop- qml-module-qtsysteminfo- ubuntu-defaults-zh-cnsnap:- -usr/share/doc- -usr/includeafter: [desktop/qt5]

confinement: devmode

$ sudo snap install rssreader-app_1.0_amd64.snap --devmode