shell脚本实现格式化JSON字串

PedroQin

发布于 2020-04-26 22:44:47

3K0

发布于 2020-04-26 22:44:47

文章被收录于专栏：WriteSimpleDemo

导言

工作中时常要上传json数据，上传前做校对时，单行的一长串json数据不方便校对，复制到 vscode中用插件实现格式化又麻烦，故有了写个脚本工具实现格式化输出json的想法。

Github

https://github.com/pedroqin/shell_script

实现效果

将单行json数据格式化为有缩进层次的多行文本。示例：

 1apple@Pedro-Mac-mini ~/D/json_tool> ./format_json.sh -f json.txt
 2{
 3  "message" : "success感谢又拍云(upyun.com)提供CDN赞助",
 4  "status" : 200,
 5  "date" : "20200422",
 6  "time" : "2020-04-22 22:22:23",
 7  "cityInfo" : {
 8    "city" : "天津市",
 9    "citykey" : "101030100",
10    "parent" : "天津",
11    "updateTime" : "17:33"
12  },
13  "data" : {
14    "shidu" : "8%",
15    "pm25" : 11.0,
16    "pm10" : 31.0,
17    "quality" : "优",
18    "wendu" : "15",
19    "ganmao" : "各类人群可自由活动",
20    "forecast" : [
21      {
22        "date" : "22",
23        "high" : "高温 16℃",
24        "low" : "低温 6℃",
25        "ymd" : "2020-04-22",
26        "week" : "星期三",
27        "sunrise" : "05:26",
28        "sunset" : "18:55",
29        "aqi" : 37,
30        "fx" : "西北风",
31        "fl" : "4-5级",
32        "type" : "晴",
33        "notice" : "愿你拥有比阳光明媚的心情"
34      }
35    ],
36    "yesterday" : {
37      "date" : "21",
38      "high" : "高温 15℃",
39      "low" : "低温 6℃",
40      "ymd" : "2020-04-21",
41      "week" : "星期二",
42      "sunrise" : "05:28",
43      "sunset" : "18:54",
44      "aqi" : 60,
45      "fx" : "西北风",
46      "fl" : "5-6级",
47      "type" : "晴",
48      "notice" : "愿你拥有比阳光明媚的心情"
49    }
50  }
51}

实现思路

视整个json数据为一个字串，依次获取每个字符。一般使用的方式有两种如下：

使用read每次获取单个字符，但需注意，使用read时需先设置$IFS(Internal Field Seprator)，否则空格会直接跳过，另还有其他一些问题，需要考虑的特殊情况较多，实现稍繁琐。

1ifs_bak="$IFS"
2IFS=$'\n'
3echo "$strings"|while ((1)); do
4    read -s -r -n 1 ch
5    judge_char "$ch"
6    [ -z "$ch" ] && break
7done
8IFS="$ifs_bak"

使用字符串截取，无使用read时的特殊情况，推荐

1offset=0
2while ((1)); do
3    ch="${strings:$offset:1}"
4    judge_char "$ch"
5    [ -z "$ch" ] && break
6    let offset++
7done

将上一步获取的字符做判断，筛选出六个构造字符（“[”、“]”、“{”、“}”、“:”、“,”），并实现对应缩进长度和换行

其他注意点

在json 对象和数组中的“[”、“]”、“{”、“}”、“:”、“,” 为普通字符，需加判断，本文处使用flag值做判断
实现缩进的关键点在于缩进字串长度的控制，以及六个构造字符打印时伴随的换行和缩进字符的打印

代码

  1#!/bin/bash
  2###############################################
  3# Filename    :   format_json.sh
  4# Author      :   PedroQin
  5# Date        :   2020-04-22 18:33:35
  6# Description :   
  7# Version     :   1.0.1
  8###############################################
  9
 10# you can diy indent ,like "\t or "  "
 11indent="  "
 12
 13##############################################
 14indent_num=0
 15indent_str=""
 16double_quotes=false
 17#A string is a sequence of zero or more Unicode characters, wrapped in double quotes, using backslash escapes. A character is represented as a single character string. A string is very much like a C or Java string. --- by https://www.json.org/json-en.html ,so single quote is not accepted !
 18#single_quote=false
 19# show message in green
 20function green_message()
 21{
 22    echo -ne "\033[32m$@\033[0m"
 23    echo
 24}
 25
 26# show message in red
 27function red_message()
 28{
 29    echo -ne "\033[31m$@\033[0m"
 30    echo
 31}
 32
 33function judge_char()
 34{
 35    case "$1" in
 36        "{")
 37        [ "$double_quotes" == "true" ] && echo -n "$1" && return
 38        let indent_num++
 39        combining_indent +
 40        echo "{"
 41        echo -ne "$indent_str"
 42        ;;
 43
 44        "}")
 45        [ "$double_quotes" == "true" ] && echo -n "$1" && return
 46        let indent_num--
 47        combining_indent -
 48        echo
 49        echo -ne "$indent_str}"
 50        ;;
 51
 52        "[")
 53        [ "$double_quotes" == "true" ] && echo -n "$1" && return
 54        let indent_num++
 55        combining_indent +
 56        echo "["
 57        echo -ne "$indent_str"
 58        ;;
 59
 60        "]")
 61        [ "$double_quotes" == "true" ] && echo -n "$1" && return
 62        let indent_num--
 63        combining_indent -
 64        echo
 65        echo -ne "$indent_str]"
 66        ;;
 67
 68        ",")
 69        [ "$double_quotes" == "true" ] && echo -n "$1" && return
 70        echo ","
 71        echo -ne "$indent_str"
 72        ;;
 73
 74        '"')
 75        [ "$double_quotes" == "true" ] && double_quotes=false || double_quotes=true
 76        echo -n '"'
 77        ;;
 78
 79        ":")
 80        [ "$double_quotes" == "false" ] && echo -n " : " || echo -n ":"
 81        ;;
 82
 83        "\\")
 84        # if get \ ,will skip the next char, mostly it is \n
 85        [ "$double_quotes" == "false" ] && let offset++ || echo -n "\\"
 86        ;;
 87
 88        *)
 89        echo -n "$1"
 90        ;;
 91
 92    esac
 93}
 94
 95function combining_indent()
 96{
 97    if [ $indent_num -lt 0 ];then
 98        red_message "Wrong Json format!"
 99        exit 255
100    fi
101    case $1 in
102        +)
103        indent_str+=$indent
104        ;;
105        -)
106        indent_str=${indent_str%"$indent"}
107        ;;
108
109    esac
110}
111
112function usage()
113{
114    cat << USAGE
115$0 -f \$json_file
116$0 \$json_str
117USAGE
118    exit 255
119}
120
121if [ "$1" == "-f" ] || [ "$1" == "--file"  ];then
122    file_name=$2
123    [ ! -f "$file_name" ] && red_message "Can't find the file :$file_name" && usage
124    strings="$(cat $file_name)"
125else
126    strings="$@"
127fi
128
129offset=0
130while ((1)); do
131    ch="${strings:$offset:1}"
132    judge_char "$ch"
133    [ -z "$ch" ] && break
134    let offset++
135done
136echo