75 lines
2.2 KiB
Go
75 lines
2.2 KiB
Go
package jsonpath
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import (
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"encoding/json"
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"fmt"
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"strconv"
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"strings"
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)
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// Eval is a half-baked json path implementation that needs some love
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func Eval(path string, b []byte) (string, int, error) {
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var object interface{}
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err := json.Unmarshal(b, &object)
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if err != nil {
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// Try to unmarshal it into an array instead
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return "", 0, err
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}
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return walk(path, object)
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}
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func walk(path string, object interface{}) (string, int, error) {
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keys := strings.Split(path, ".")
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currentKey := keys[0]
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switch value := extractValue(currentKey, object).(type) {
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case map[string]interface{}:
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return walk(strings.Replace(path, fmt.Sprintf("%s.", currentKey), "", 1), value)
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case string:
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return value, len(value), nil
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case []interface{}:
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return fmt.Sprintf("%v", value), len(value), nil
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case interface{}:
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return fmt.Sprintf("%v", value), 1, nil
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default:
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return "", 0, fmt.Errorf("couldn't walk through '%s' because type was '%T', but expected 'map[string]interface{}'", currentKey, value)
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}
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}
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func extractValue(currentKey string, value interface{}) interface{} {
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// Check if the current key ends with [#]
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if strings.HasSuffix(currentKey, "]") && strings.Contains(currentKey, "[") {
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tmp := strings.SplitN(currentKey, "[", 3)
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arrayIndex, err := strconv.Atoi(strings.Replace(tmp[1], "]", "", 1))
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if err != nil {
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return value
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}
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currentKey := tmp[0]
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// if currentKey contains only an index (i.e. [0] or 0)
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if len(currentKey) == 0 {
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array := value.([]interface{})
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if len(array) > arrayIndex {
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if len(tmp) > 2 {
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// Nested array? Go deeper.
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return extractValue(fmt.Sprintf("%s[%s", currentKey, tmp[2]), array[arrayIndex])
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}
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return array[arrayIndex]
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}
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return nil
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}
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if value == nil || value.(map[string]interface{})[currentKey] == nil {
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return nil
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}
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// if currentKey contains both a key and an index (i.e. data[0])
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array := value.(map[string]interface{})[currentKey].([]interface{})
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if len(array) > arrayIndex {
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if len(tmp) > 2 {
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// Nested array? Go deeper.
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return extractValue(fmt.Sprintf("[%s", tmp[2]), array[arrayIndex])
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}
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return array[arrayIndex]
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}
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return nil
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}
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return value.(map[string]interface{})[currentKey]
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}
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