每天自动获取 Bing 壁纸

1 利弊分析
2 战前准备
3 战斗开始

自从换了 mac 之后，直观的感觉是桌面变的更空旷了（本来我就不喜欢在桌面放东西）。所以，壁纸成了装点桌面的唯一工具。正好 Bing 的背景图片每天都会换一张，并且几乎每张图片都让人感觉非常大气，所以就萌生了用 Bing 图片做壁纸的想法（话说让我知道 Bing 每天都会换背景图，还是因为之前做 Kratos 的时候有小伙伴提出网页的背景图能不能调用 Bing 的接口。我先看了一下 Apple Store 里面有没有这种 App，果不其然还真有，但是这价格的话，emmmmm 算了还是自己整吧。

利弊分析

Bing 的图片有 4 种像素，分别是 1920x1200、1920x1080、800x480、400x240，而 mac 可以支持到 2880 x 1800，所以在视觉上看着壁纸不是非常的清晰的（系统自带的壁纸是 5120 × 3684）。

这里制作的自动化脚本是每次开机启动的，如果一天开机好几次的话，脚本会自带检测是否已经下载过图片，从而不会重复下载。

战前准备

MAC 中自带的 Automator
bing-wallpaper 脚本

战斗开始

1、首先我们知道 Bing 图片是有一个接口的，也就是 https://cn.bing.com/HPImageArchive.aspx?format=js&n=1 ，他的主要内容如下，这里我们需要的是第 7 行 url，也就是图片的地址，所以在脚本中只要拉这个 url 地址即可实现需求。

{
    images: [
        {
            startdate: "20180315",
            fullstartdate: "201803151600",
            enddate: "20180316",
            url: "/az/hprichbg/rb/WolongPanda_ZH-CN10957042976_1920x1080.jpg",
            urlbase: "/az/hprichbg/rb/WolongPanda_ZH-CN10957042976",
            copyright: "卧龙国家级自然保护区的大熊猫，中国四川 (© Lynn M. Stone/Minden Pictures)",
            copyrightlink: "http://www.bing.com/search?q=%E5%A4%A7%E7%86%8A%E7%8C%AB&form=hpcapt&mkt=zh-cn",
            quiz: "/search?q=Bing+homepage+quiz&filters=WQOskey:%22HPQuiz_20180315_WolongPanda%22&FORM=HPQUIZ",
            wp: false,
            hsh: "6fa3921773323a6e7f0f45447e548f91",
            drk: 1,
            top: 1,
            bot: 1,
            hs: [ ]
        }
    ],
    tooltips: {
        loading: "正在加载...",
        previous: "上一个图像",
        next: "下一个图像",
        walle: "此图片不能下载用作壁纸。",
        walls: "下载今日美图。仅限用作桌面壁纸。"
    }
}

2、bing-wallpaper 是一个可以从 Bing 下载当天最新图片并将其保存到目录的脚本。

#!/usr/bin/env bash
# shellcheck disable=SC1117

readonly SCRIPT= $(basename "$ 0")
readonly VERSION='0.4.0'
readonly RESOLUTIONS=(1920x1200 1920x1080 800x480 400x240)

usage() {
cat <<EOF
Usage:
   $SCRIPT [options]$ SCRIPT -h | --help
   $SCRIPT --version Options: -f --force Force download of picture. This will overwrite the picture if the filename already exists. -s --ssl Communicate with bing.com over SSL. -q --quiet Do not display log messages. -n --filename <file name> The name of the downloaded picture. Defaults to the upstream name. -p --picturedir <picture dir> The full path to the picture download dir. Will be created if it does not exist. [default:$ HOME/Pictures/bing-wallpapers/]
  -r --resolution <resolution>   The resolution of the image to retrieve.
                                 Supported resolutions:  ${RESOLUTIONS[*]} -w --set-wallpaper Set downloaded picture as wallpaper (Only mac support for now). -h --help Show this screen. --version Show version. EOF } print_message() { if [ ! "$ QUIET" ]; then
        printf "%s\n" " ${1}" fi } # Defaults PICTURE_DIR="$ HOME/Pictures/bing-wallpapers/"
RESOLUTION="1920x1080"

# Option parsing
while [[  $# -gt 0 ]]; do key="$ 1"

    case  $key in -r|--resolution) RESOLUTION="$ 2"
            shift
            ;;
        -p|--picturedir)
            PICTURE_DIR=" $2" shift ;; -n|--filename) FILENAME="$ 2"
            shift
            ;;
        -f|--force)
            FORCE=true
            ;;
        -s|--ssl)
            SSL=true
            ;;
        -q|--quiet)
            QUIET=true
            ;;
        -h|--help)
            usage
            exit 0
            ;;
        -w|--set-wallpaper)
            SET_WALLPAPER=true
            ;;
        --version)
            printf "%s\n"  $VERSION exit 0 ;; *) (>&2 printf "Unknown parameter: %s\n" "$ 1")
            usage
            exit 1
            ;;
    esac
    shift
done

# Set options
[  $QUIET ] && CURL_QUIET='-s' [$ SSL ]   && PROTO='https'   || PROTO='http'

# Create picture directory if it doesn't already exist
mkdir -p " ${PICTURE_DIR}" # Parse bing.com and acquire picture URL(s) read -ra urls<<(curl -sL$ PROTO://www.bing.com | \
    grep -Eo "url:'.*?'" | \
    sed -e "s/url:'\([^']*\)'.*/ $PROTO:\/\/bing.com\1/" | \ sed -e "s/\\\//g" | \ sed -e "s/\([[:digit:]]*x[[:digit:]]*\)/$ RESOLUTION/")

for p in " ${urls[@]}"; do if [ -z "$ FILENAME" ]; then
        filename= $(echo "$ p"|sed -e "s/.*\/\(.*\)/\1/")
    else
        filename=" $FILENAME" fi if [$ FORCE ] || [ ! -f " $PICTURE_DIR/$ filename" ]; then
        print_message "Downloading:  $filename..." curl$ CURL_QUIET -Lo " $PICTURE_DIR/$ filename" " $p" else print_message "Skipping:$ filename..."
    fi
done

if [  $SET_WALLPAPER ]; then /usr/bin/osascript<<END tell application "System Events" to set picture of every desktop to ("$ PICTURE_DIR/$filename" as POSIX file as alias)
END
fi