openwrt shell使用json

openwrt中在shell中对json数据进行了处理，通过设置一些环境变量的值，来索引一个json数据。

jshc.sh是一个脚本，提供了一些设置json数据的环境变量
jshc是一个c写的获取环境变量，并解析出来json数据的函数，比如使用方法json -w。

gcc -o jshn jshn.c -ljson-c -I/usr/local/include/json-c        //可以使用的编译方式。

export K_J_V="hello world"


export J_V_hello=karl
export T_J_V_hello=string
export N_J_V_hello=kim


export J_V_world=liu
export T_J_V_world=object
export N_J_V_world=ssss


export K_liu="li dongwu"
export liu_li=my
export T_liu_li=string
export N_liu_li=yang


export liu_dongwu="mao"
export T_liu_dongwu=string
export N_liu_dongwu="cat"
./jshn -w


J_V为一个object，这个object包含了一系列的子object。所以必须有K_J_V表示每一个子object.


对于其中的一个子object,比如hello.
必须有如下资料
J_V_hello 表示对象的值
T_J_V_hello 表示对象的类型
N_J_V_hello 表示对象的名字


比如字符串
J_V_hello="string value"
比如对象
J_V_hello="envsubobject"
envsubobject包含的对象如何去找到，则需要继续找
K_envsubobject="subobj1 subobj2"
这样后面的子对象
envsubobject_subobj1="value1"
T_envsuboject_subobj1=string
N_envsubobject_subobject1="subobj1"

附jshc.c源码：

/*
 * Copyright (C) 2011-2013 Felix Fietkau <[e-mail]>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
        #include <json.h>

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <ctype.h>
#include <getopt.h>

#define MAX_VARLEN    256


static const char *var_prefix = "";
static int var_prefix_len = 0;

static int add_json_element(const char *key, json_object *obj);

static int add_json_object(json_object *obj)
{
    int ret = 0;

    json_object_object_foreach(obj, key, val) {
        ret = add_json_element(key, val);
        if (ret)
            break;
    }
    return ret;
}

static int add_json_array(struct array_list *a)
{
    char seq[12];
    int i, len;
    int ret;

    for (i = 0, len = array_list_length(a); i < len; i++) {
        sprintf(seq, "%d", i);
        ret = add_json_element(seq, array_list_get_idx(a, i));
        if (ret)
            return ret;
    }

    return 0;
}

static void add_json_string(const char *str)
{
    char *ptr = (char *) str;
    int len;
    char *c;

    while ((c = strchr(ptr, '\'')) != NULL) {
        len = c - ptr;
        if (len > 0)
            fwrite(ptr, len, 1, stdout);
        ptr = c + 1;
        c = "'\\''";
        fwrite(c, strlen(c), 1, stdout);
    }
    len = strlen(ptr);
    if (len > 0)
        fwrite(ptr, len, 1, stdout);
}

static void write_key_string(const char *key)
{
    while (*key) {
        putc(isalnum(*key) ? *key : '_', stdout);
        key++;
    }
}

static int add_json_element(const char *key, json_object *obj)
{
    char *type;

    if (!obj)
        return -1;

    switch (json_object_get_type(obj)) {
    case json_type_object:
        type = "object";
        break;
    case json_type_array:
        type = "array";
        break;
    case json_type_string:
        type = "string";
        break;
    case json_type_boolean:
        type = "boolean";
        break;
    case json_type_int:
        type = "int";
        break;
    case json_type_double:
        type = "double";
        break;
    default:
        return -1;
    }

    fprintf(stdout, "json_add_%s '", type);
    write_key_string(key);

    switch (json_object_get_type(obj)) {
    case json_type_object:
        fprintf(stdout, "';\n");
        add_json_object(obj);
        fprintf(stdout, "json_close_object;\n");
        break;
    case json_type_array:
        fprintf(stdout, "';\n");
        add_json_array(json_object_get_array(obj));
        fprintf(stdout, "json_close_array;\n");
        break;
    case json_type_string:
        fprintf(stdout, "' '");
        add_json_string(json_object_get_string(obj));
        fprintf(stdout, "';\n");
        break;
    case json_type_boolean:
        fprintf(stdout, "' %d;\n", json_object_get_boolean(obj));
        break;
    case json_type_int:
        fprintf(stdout, "' %d;\n", json_object_get_int(obj));
        break;
    case json_type_double:
        fprintf(stdout, "' %lf;\n", json_object_get_double(obj));
        break;
    default:
        return -1;
    }

    return 0;
}

static int jshn_parse(const char *str)
{
    json_object *obj;

    obj = json_tokener_parse(str);
    if (!obj || json_object_get_type(obj) != json_type_object) {
        fprintf(stderr, "Failed to parse message data\n");
        return 1;
    }
    fprintf(stdout, "json_init;\n");
    add_json_object(obj);
    fflush(stdout);

    return 0;
}

static char *get_keys(const char *prefix)
{
    char *keys;

    keys = alloca(var_prefix_len + strlen(prefix) + sizeof("K_") + 1);
    sprintf(keys, "%sK_%s", var_prefix, prefix);
    printf("getenv %s\n", keys);
    return getenv(keys);
}

static void get_var(const char *prefix, const char **name, char **var, char **type)
{
    char *tmpname, *varname;

    tmpname = alloca(var_prefix_len + strlen(prefix) + 1 + strlen(*name) + 1 + sizeof("T_"));

    sprintf(tmpname, "%s%s_%s", var_prefix, prefix, *name);
    *var = getenv(tmpname);
    printf("getenv %s=%s\n", tmpname, *var);

    sprintf(tmpname, "%sT_%s_%s", var_prefix, prefix, *name);
    *type = getenv(tmpname);
    printf("getenv %s=%s\n", tmpname, *type);

    sprintf(tmpname, "%sN_%s_%s", var_prefix, prefix, *name);
    varname = getenv(tmpname);
    printf("getenv %s=%s\n", tmpname, varname);
    if (varname)
        *name = varname;
}

static json_object *jshn_add_objects(json_object *obj, const char *prefix, bool array);

static void jshn_add_object_var(json_object *obj, bool array, const char *prefix, const char *name)
{
    json_object *new;
    char *var, *type;

    get_var(prefix, &name, &var, &type);
    if (!var || !type)
        return;

    if (!strcmp(type, "array")) {
        new = json_object_new_array();
        jshn_add_objects(new, var, true);
    } else if (!strcmp(type, "object")) {
        new = json_object_new_object();
        jshn_add_objects(new, var, false);
    } else if (!strcmp(type, "string")) {
        new = json_object_new_string(var);
    } else if (!strcmp(type, "int")) {
        new = json_object_new_int(atoi(var));
    } else if (!strcmp(type, "double")) {
        new = json_object_new_double(strtod(var, NULL));
    } else if (!strcmp(type, "boolean")) {
        new = json_object_new_boolean(!!atoi(var));
    } else {
        return;
    }

    if (array)
        json_object_array_add(obj, new);
    else
        json_object_object_add(obj, name, new);
}

static json_object *jshn_add_objects(json_object *obj, const char *prefix, bool array)
{
    char *keys, *key, *brk;

    keys = get_keys(prefix);
    printf("prefix=%s, keys=%s\n", prefix, keys);
    if (!keys || !obj)
        goto out;

    for (key = strtok_r(keys, " ", &brk); key;
         key = strtok_r(NULL, " ", &brk)) {
        jshn_add_object_var(obj, array, prefix, key);
    }

out:
    return obj;
}

static int jshn_format(bool no_newline, bool indent)
{
    json_object *obj;
    const char *output;
    int ret = -1;

    if (!(obj = json_object_new_object()))
        return -1;

    jshn_add_objects(obj, "J_V", false);
    if (!(output = json_object_to_json_string(obj)))
        goto out;

    if (indent) {
    }
    fprintf(stdout, "%s%s", output, no_newline ? "" : "\n");
    ret = 0;

out:
    json_object_put(obj);
    return ret;
}

static int usage(const char *progname)
{
    fprintf(stderr, "Usage: %s [-n] [-i] -r |-w\n", progname);
    return 2;
}

int main(int argc, char **argv)
{
    bool no_newline = false;
    bool indent = false;
    int ch;

    while ((ch = getopt(argc, argv, "p:nir:w")) != -1) {
        switch(ch) {
        case 'p':
            var_prefix = optarg;
            var_prefix_len = strlen(var_prefix);
            break;
        case 'r':
            return jshn_parse(optarg);
        case 'w':
            return jshn_format(no_newline, indent);
        case 'n':
            no_newline = true;
            break;
        case 'i