遍历array并获取结构体成员分析

假设有一个数组类型域，其成员是一个结构类型，例如：

{
  "docs": [
    {
      "name": "Tom",
      "age": 20,
      "address": "Tom's address"
    },
    {
      "name": "Jerry",
      "age": 30,
      "address": "200 Land"
    },
    {
      "name": "Jack",
      "age": 30,
      "address": "New address"
    }
  ]
}

如果使用遍历数组，拿到每一个struct用来分析呢：

#!/bin/bash

cat test.json | jq '.docs[]' | while read doc; do
  echo $doc
done

看起来很合理，运行一下呢：

{
"name": "Tom",
"age": 20,
"address": "Tom's address"
}
{
"name": "Jerry",
"age": 30,
"address": "200 Land"
}
{
"name": "Jack",
"age": 30,
"address": "New address"
}

看不出效果：

$ cat test.json
#!/bin/bash

cat test.json | jq '.docs[]' | while read doc; do
  echo "DOC="$doc
done

$ ./test.sh
DOC={
DOC="name": "Tom",
DOC="age": 20,
DOC="address": "Tom's address"
DOC=}
DOC={
DOC="name": "Jerry",
DOC="age": 30,
DOC="address": "200 Land"
DOC=}
DOC={
DOC="name": "Jack",
DOC="age": 30,
DOC="address": "New address"
DOC=}

这下看清楚了，显然是不行的，我们得想办法把一个元素拼成一行才好。

$ cat test.json
#!/bin/bash

cat test.json | jq -c '.docs[]' | while read doc; do
  echo "DOC="$doc
done

$ ./test.sh
DOC={"name":"Tom","age":20,"address":"Tom's address"}
DOC={"name":"Jerry","age":30,"address":"200 Land"}
DOC={"name":"Jack","age":30,"address":"New address"}

这是我们的目标，于是在循环里面可以访问struct的成员：

$ cat test.json
#!/bin/bash

cat test.json | jq -c '.docs[]' | while read doc; do
  name=$(echo $doc | jq .name)
  age=$(echo $doc | jq .age)
  address=$(echo $doc | jq .address)
  echo name=$name, age=$age, address=$address
done

$ ./test.sh
name="Tom", age=20, address="Tom's address"
name="Jerry", age=30, address="200 Land"
name="Jack", age=30, address="New address"

如果含有特殊符合怎么处理，我们可以先进行base64编码，然后在使用的时候解码：

$ cat test.sh
#!/bin/bash

cat test.json | jq -rc '.docs[] | @base64' | while read doc; do
  doc=$(echo $doc | base64 -d)
  name=$(echo $doc | jq .name)
  age=$(echo $doc | jq .age)
  address=$(echo $doc | jq .address)
  echo name=$name, age=$age, address=$address
done

$ ./test.sh
name="Tom", age=20, address="Tom's address"
name="Jerry", age=30, address="200 Land"
name="Jack", age=30, address="New address"