How to Convert Snake-Case to CamelCase Keys in JSON Using Go?

Converting Snake-Case to CamelCase Keys in JSON

In Go, converting keys in a JSON document from snake_case to camelCase can be challenging, especially when the JSON is nested and may contain arbitrarily large or interface{} types.

Method 1: Using Different Structs with Tags

For simple conversion cases, you can leverage Go's ability to define different structs with varying tags. Unmarshal the JSON into the source struct with snake_case tags, then trivially convert it to the target struct with camelCase tags.

<code class="go">import (
    "encoding/json"
)

// Source struct with snake_case tags
type ESModel struct {
    AB string `json:"a_b"`
}

// Target struct with camelCase tags
type APIModel struct {
    AB string `json:"aB"`
}

func ConvertKeys(json []byte) []byte {
    var x ESModel
    json.Unmarshal(b, &x)

    b, _ = json.MarshalIndent(APIModel(x), "", "  ")
    return b
}</code>

Method 2: Recursively Converting Map Keys

For more complex JSON documents, you can attempt to unmarshal it into a map. If successful, recursively apply the key conversion function to all keys and values within the map.

<code class="go">import (
    "bytes"
    "encoding/json"
    "fmt"
    "strings"
)

func ConvertKeys(j json.RawMessage) json.RawMessage {
    m := make(map[string]json.RawMessage)
    if err := json.Unmarshal([]byte(j), &m); err != nil {
        // Not a JSON object
        return j
    }

    for k, v := range m {
        fixed := fixKey(k)
        delete(m, k)
        m[fixed] = convertKeys(v)
    }

    b, err := json.Marshal(m)
    if err != nil {
        return j
    }

    return json.RawMessage(b)
}

func fixKey(key string) string {
    return strings.ToUpper(key)
}</code>

The above is the detailed content of How to Convert Snake-Case to CamelCase Keys in JSON Using Go?. For more information, please follow other related articles on the PHP Chinese website!