Method HSetNX

structure/hash.go:1047–1095

HSetNX sets a field in the hash only if the field does not already exist. It takes a string key 'k', a field 'f', and a value 'v' to set if the field doesn't exist. It returns a boolean indicating whether the field was set and any possible error. Parameters: k: The key of the hash table. f: The

(key string, field, value interface{})

//	bool: True if the field was set, false otherwise.
//	error: An error if occurred during the operation, or nil on success.
func (hs *HashStructure) HSetNX(key string, field, value interface{}) (bool, error) {
	// Convert the parameters to bytes
	k := stringToBytesWithKey(key)

	// Convert the parameters to bytes
	f, err, _ := interfaceToBytes(field)
	if err != nil {
		return false, err
	}

	// Convert the parameters to bytes
	v, err, _ := interfaceToBytes(value)
	if err != nil {
		return false, err
	}

	// Check the parameters
	if len(k) == 0 || len(f) == 0 || len(v) == 0 {
		return false, _const.ErrKeyIsEmpty
	}

	// Find the hash metadata by the given key
	hashMeta, err := hs.findHashMeta(key, Hash)
	if err != nil {
		return false, err
	}

	// Create a new HashField
	hf := &HashField{
		field:   f,
		key:     k,
		version: hashMeta.version,
	}

	// Encode the HashField
	hfBuf := hf.encodeHashField()

	// Get the field from the database
	_, err = hs.db.Get(hfBuf)
	if err != nil && err == _const.ErrKeyNotFound {
		_, err := hs.HSet(key, field, value)
		if err != nil {
			return false, err
		}
		return true, nil
	} else {
		return false, nil
	}
}

// HTypes returns the type of a field in the hash.
// It takes a string key 'k' and a field 'f'.