如何修改JSON值

Question

我有这样的JSON消息：

{"name":"Kallel", "birthdate":"01/01/2012"} 

的JSON消息的treatement与shell脚本（SH）

做我

加载JSON消息

json_init 
json_load "$msg" 

我想然后编辑"birthdate"值。如何用json脚本函数做到这一点？没有重建JSON消息。我只是想编辑值。

我使用这个JSON脚本文件包括JSON功能：

jshn.sh（从开源libubox）

# functions for parsing and generating json 

_json_get_var() { 
    local ___dest="$1" 
    local ___var="$2" 
    eval "$___dest=\"\$${JSON_PREFIX}$___var\"" 
} 

_json_set_var() { 
    local ___var="$1" 
    local ___val="$2" 
    eval "${JSON_PREFIX}$___var=\"\$___val\"" 
} 

_jshn_append() { 
    local __var="$1" 
    local __value="$2" 
    local __sep="${3:- }" 
    local __old_val 

    _json_get_var __old_val "$__var" 
    __value="${__old_val:+$__old_val$__sep}$__value" 
    _json_set_var "$__var" "$__value" 
} 

_json_export() { 
    local __var="${JSON_PREFIX}$1" 
    local __val="$2" 

    export -- "$__var=$__val" 
    _jshn_append "JSON_UNSET" "$__var" 
} 

_json_add_key() { 
    local table="$1" 
    local var="$2" 
    _jshn_append "KEYS_${table}" "$var" 
} 

_get_var() { 
    local __dest="$1" 
    local __var="$2" 
    eval "$__dest=\"\$$__var\"" 
} 

_set_var() { 
    local __var="$1" 
    local __val="$2" 
    eval "$__var=\"\$__val\"" 
} 

_json_inc() { 
    local _var="$1" 
    local _dest="$2" 
    local _seq 

    _json_get_var _seq "$_var" 
    _seq="$((${_seq:-0} + 1))" 
    _json_set_var "$_var" "$_seq" 
    [ -n "$_dest" ] && _set_var "$_dest" "$_seq" 
} 

_json_stack_push() { 
    local new_cur="$1" 
    local cur 

    _json_get_var cur JSON_CUR 
    _jshn_append JSON_STACK "$cur" 
    _json_set_var JSON_CUR "$new_cur" 
} 

_json_add_generic() { 
    local type="$1" 
    local var="$2" 
    local val="$3" 
    local cur="$4" 

    [ -n "$cur" ] || _json_get_var cur JSON_CUR 

    if [ "${cur%%[0-9]*}" = "JSON_ARRAY" ]; then 
     _json_inc "SEQ_$cur" var 
    else 
     local name="${var//[^a-zA-Z0-9_]/_}" 
     [[ "$name" == "$var" ]] || _json_export "NAME_${cur}_${name}" "$var" 
     var="$name" 
    fi 

    _json_export "${cur}_$var" "$val" 
    _json_export "TYPE_${cur}_$var" "$type" 
    _json_add_key "$cur" "$var" 
} 

_json_add_table() { 
    local name="$1" 
    local type="$2" 
    local itype="$3" 
    local cur new_cur 
    local seq 

    _json_get_var cur JSON_CUR 
    _json_inc JSON_SEQ seq 

    local table="JSON_$itype$seq" 
    _json_export "UP_$table" "$cur" 
    _json_export "KEYS_$table" "" 
    [ "$itype" = "ARRAY" ] && _json_export "SEQ_$table" "" 
    _json_stack_push "$table" 

    _json_get_var new_cur JSON_CUR 
    _json_add_generic "$type" "$1" "$new_cur" "$cur" 
} 

_json_close_table() { 
    local stack new_stack 

    _json_get_var stack JSON_STACK 
    _json_set_var JSON_CUR "${stack##* }" 
    new_stack="${stack% *}" 
    [[ "$stack" == "$new_stack" ]] && new_stack= 
    _json_set_var JSON_STACK "$new_stack" 
} 

json_set_namespace() { 
    local _new="$1" 
    local _old="$2" 

    [ -n "$_old" ] && _set_var "$_old" "$JSON_PREFIX" 
    JSON_PREFIX="$_new" 
} 

json_cleanup() { 
    local unset 

    _json_get_var unset JSON_UNSET 
    [ -n "$unset" ] && eval "unset $unset" 

    unset \ 
     ${JSON_PREFIX}JSON_SEQ \ 
     ${JSON_PREFIX}JSON_STACK \ 
     ${JSON_PREFIX}JSON_CUR \ 
     ${JSON_PREFIX}JSON_UNSET \ 
     ${JSON_PREFIX}KEYS_JSON_VAR \ 
     ${JSON_PREFIX}TYPE_JSON_VAR 
} 

json_init() { 
    json_cleanup 
    export -- \ 
     ${JSON_PREFIX}JSON_SEQ=0 \ 
     ${JSON_PREFIX}JSON_STACK= \ 
     ${JSON_PREFIX}JSON_CUR="JSON_VAR" \ 
     ${JSON_PREFIX}JSON_UNSET="" \ 
     ${JSON_PREFIX}KEYS_JSON_VAR= \ 
     ${JSON_PREFIX}TYPE_JSON_VAR= 
} 

json_add_object() { 
    _json_add_table "$1" object TABLE 
} 

json_close_object() { 
    _json_close_table 
} 

json_add_array() { 
    _json_add_table "$1" array ARRAY 
} 

json_close_array() { 
    _json_close_table 
} 

json_add_string() { 
    _json_add_generic string "$1" "$2" 
} 

json_add_int() { 
    _json_add_generic int "$1" "$2" 
} 

json_add_boolean() { 
    _json_add_generic boolean "$1" "$2" 
} 

# functions read access to json variables 

json_load() { 
    eval `jshn -r "$1"` 
} 

json_dump() { 
    jshn "$@" ${JSON_PREFIX:+-p "$JSON_PREFIX"} -w 
} 

json_get_type() { 
    local __dest="$1" 
    local __cur 

    _json_get_var __cur JSON_CUR 
    local __var="${JSON_PREFIX}TYPE_${__cur}_${2//[^a-zA-Z0-9_]/_}" 
    eval "export -- \"$__dest=\${$__var}\"; [ -n \"\${$__var+x}\" ]" 
} 

json_get_var() { 
    local __dest="$1" 
    local __cur 

    _json_get_var __cur JSON_CUR 
    local __var="${JSON_PREFIX}${__cur}_${2//[^a-zA-Z0-9_]/_}" 
    eval "export -- \"$__dest=\${$__var}\"; [ -n \"\${$__var+x}\" ]" 
} 

json_get_vars() { 
    while [ "$#" -gt 0 ]; do 
     local _var="$1"; shift 
     json_get_var "$_var" "$_var" 
    done 
} 

json_select() { 
    local target="$1" 
    local type 
    local cur 

    [ -z "$1" ] && { 
     _json_set_var JSON_CUR "JSON_VAR" 
     return 0 
    } 
    [[ "$1" == ".." ]] && { 
     _json_get_var cur JSON_CUR 
     _json_get_var cur "UP_$cur" 
     _json_set_var JSON_CUR "$cur" 
     return 0 
    } 
    json_get_type type "$target" 
    case "$type" in 
     object|array) 
      json_get_var cur "$target" 
      _json_set_var JSON_CUR "$cur" 
     ;; 
     *) 
      echo "WARNING: Variable '$target' does not exist or is not an array/object" 
      return 1 
     ;; 
    esac 
} 

json_is_a() { 
    local type 

    json_get_type type "$1" 
    [ "$type" = "$2" ] 
} 

Answer 1

你会更好使用的语言与真实，测试JSON分析器，例如Perl的：

#!/usr/bin/perl 
use strict; 
use warnings; 
use JSON; 
# not required, just for this demonstration: 
use Time::Piece; 
use Time::Seconds; 

while (<>) { 
    my $json = decode_json $_; 

    # now, do something with the data: 
    my $bday = Time::Piece->strptime($json->{birthdate}, "%m/%d/%Y"); 
    $bday -= ONE_MONTH; 
    $json->{birthdate} = $bday->strftime("%m/%d/%Y"); 

    # and print it back out 
    print encode_json($json), "\n"; 
} 

perl json.pl <<END 
{"name":"Kallel", "birthdate":"01/01/2012"} 
END 

{"birthdate":"12/01/2011","name":"Kallel"}