在json文件中使用变量 [英] Using variables inside json file

问题描述

我需要定义一次变量，并在整个json文件中使用它.

I need to define a variable once and use it throughout the json file.

这是我的MWE :(改编自此处)

Here is my MWE: (adapted from here)

{
  "variables": {
    "my_access_key": "abc",
    "my_secret_key": "def"
  },
  "objectB": {
    "type": "1",
    "access_key": "{{user `my_access_key`}}",
    "secret_key": "{{user `my_secret_key`}}"
  },
  "objectA": {
    "type": "2",
    "access_key": "{{user `my_access_key`}}",
    "secret_key": "{{user `my_secret_key`}}"
  }
}

对象objectB和objectA的access_key字段必须等于"abc"，这是我在文件开头定义的.

The access_key field of the objects objectB and objectA must be equal to "abc", which is defined by me in the beginning of the file.

我如何在python中实现这个目标?

How can I achieve this goal in python?

推荐答案

JSON不允许引用变量

在YAML中，您可以定义变量，为其设置参考名称，然后稍后在文件中重复使用它们.

JSON does not allow variable referencing

In YAML, you may define variables, set reference names for them and then reuse them later on in the file.

JSON不提供这种功能，您必须自己逐个设置这些值.

JSON does not provide this sort of functionality, you have to set these values yourself place by place.

import json

access = "AAA"
secret = "XXX"

dct = {"variables": {"my_access_key": access, "my_secret_key": secret},
       "objectB": {"type": "1", "access_key": access, "secret_key": secret},
       "objectA": {"type": "2", "access_key": access, "secret_key": secret}
      }
json_str = json.dumps(dct, indent=True)
print json_str

打印什么

{
 "objectA": {
  "access_key": "AAA", 
  "secret_key": "XXX", 
  "type": "2"
 }, 
 "variables": {
  "my_secret_key": "XXX", 
  "my_access_key": "AAA"
 }, 
 "objectB": {
  "access_key": "AAA", 
  "secret_key": "XXX", 
  "type": "1"
 }
}

使用YAML锚点和引用

您可以为此目的使用YAML功能.由于YAML很容易编辑，因此它可能是配置文件的不错选择.

Use YAML anchors and references

You might use YAML feature for this purpose. As YAML is rather easy to edit, it could be good option for config files.

在使用它之前，请确保已安装pyyaml:

Before you use it, be sure, you install pyyaml:

$ pip install pyyaml

然后输入代码(在variables中已修改名称以满足我们的需要):

Then the code (with modified names in variables to fit our needs):

import json
import yaml
yaml_str = """
variables: &keys
    access_key: abc
    secret_key: def
objectB:
    <<: *keys
    type: "1"
objectA:
    <<: *keys
    type: "2"
"""

dct = yaml.load(yaml_str)
json_str = json.dumps(dct, indent=True)
print json_str

可打印

{
 "objectA": {
  "access_key": "abc", 
  "secret_key": "def", 
  "type": "2"
 }, 
 "variables": {
  "access_key": "abc", 
  "secret_key": "def"
 }, 
 "objectB": {
  "access_key": "abc", 
  "secret_key": "def", 
  "type": "1"
 }
}

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