127 lines
2.5 KiB
Go
127 lines
2.5 KiB
Go
package cnf
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import (
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"encoding/json"
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"fmt"
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"io"
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"strings"
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)
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type Json struct {
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data interface{}
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parsed bool
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}
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// Parse extract a reader as its JSON representation
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func (d *Json) Parse(_reader io.Reader) error {
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// 1. get json decoder
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decoder := json.NewDecoder(_reader)
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err := decoder.Decode(&d.data)
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if err != nil {
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return err
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}
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d.parsed = true
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return nil
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}
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// browse returns the target of a dot-separated path (as an interface{} chain where the last is the target if found)
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func (d *Json) browse(_path string) ([]interface{}, bool) {
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// 1. extract path
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path := strings.Split(_path, ".")
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// 2. init output chain
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current := d.data
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chain := make([]interface{}, 0, len(path)+1)
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chain = append(chain, current)
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// 3. iterate over path / nested fields
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for _, field := range path {
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fmap, ok := current.(map[string]interface{})
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if !ok { // incomplete path
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return chain, false
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}
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child, ok := fmap[field]
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if !ok { // incomplete path
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return chain, false
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}
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current = child
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chain = append(chain, current)
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}
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return chain, true
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}
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// Get returns the value of a dot-separated path, and if it exists
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func (d *Json) Get(_path string) (string, bool) {
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// 1. browse path
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chain, found := d.browse(_path)
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if !found {
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return "", false
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}
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// 2. return if string value
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value, ok := chain[len(chain)-1].(string)
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return value, ok
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}
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// Set the value of a dot-separated path, and creates it if not found
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func (d *Json) Set(_path, _value string) bool {
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// 1. browse path + create it if does not exist
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path := strings.Split(_path, ".")
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chain, found := d.browse(_path)
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// 2. if found -> set value
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if found {
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mapWrapper, ok := chain[len(chain)-2].(map[string]interface{})
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if !ok { // impossible
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return false
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}
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key := path[len(path)-1]
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mapWrapper[key] = _value
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return true
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}
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// 3. create path until the end to set value
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root := make(map[string]interface{})
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current := root
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// create children until second to last
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fmt.Printf("%d / %d\n", len(chain)-1, len(path))
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for i, l := len(chain)-1, len(path)-1; i < l; i++ {
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child := make(map[string]interface{})
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fmt.Printf("add '%s'\n", path[i])
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current[path[i]] = child
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current = child
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}
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// set value
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current[path[len(path)-1]] = _value
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// replace whole object if empty
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if len(chain) < 2 {
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d.data = root
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return true
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}
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// update last found object to add the value
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wrapper, ok := chain[len(chain)-2].(map[string]interface{})
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if !ok { // impossible
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return false
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}
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key := path[len(chain)-2]
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wrapper[key] = root
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return true
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}
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