dragonchain/dragonchain-sdk-go

// Copyright 2020 Dragonchain, Inc. or its affiliates. All Rights Reserved.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//     http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package dragonchain

import (
    "errors"
    "io/ioutil"
    "os"
    "path/filepath"
    "regexp"
    "runtime"

    "github.com/go-ini/ini"
)

// ConfigFilePath points to the location of the Configuration file
// Default on windows '%LOCALAPPDATA%\dragonchain\credentials'
// Default on linux '$HOME/.dragonchain/credentials'
// This may be overridden before creating Credentials
var ConfigFilePath = ""
var configs *Configuration

// ErrNoConfigurationFileFound is returned if no config was found in ConfigFilePath.
var ErrNoConfigurationFileFound = errors.New("no Configuration file found")

func init() {
    if runtime.GOOS == "windows" {
        ConfigFilePath = filepath.Join(os.ExpandEnv("${LOCALAPPDATA}"), "dragonchain", "credentials")
    } else {
        ConfigFilePath = filepath.Join(os.ExpandEnv("${HOME}"), ".dragonchain", "credentials")
    }
}

// AuthKey defines the structure of the chain's HMAC authorization keys.
type AuthKey struct {
    AuthKey   string
    AuthKeyID string
}

// Configuration defines the SDK configuration of chainID and AuthKeys.
type Configuration struct {
    DefaultDcID string
    AuthKeys    map[string]*AuthKey
}

// GetCredentialConfigs returns
func GetCredentialConfigs() (*Configuration, error) {
    if configs != nil {
        return configs, nil
    }

    configBytes, err := getConfigFile()
    if err != nil {
        return nil, err
    } else if configBytes == nil {
        return nil, ErrNoConfigurationFileFound
    }

    cfg, err := ini.Load(configBytes)
    if err != nil {
        return nil, err
    }

    dcID := cfg.Section("default").Key("dragonchain_id").String()

    configs = &Configuration{
        DefaultDcID: dcID,
        AuthKeys:    make(map[string]*AuthKey),
    }

    for _, section := range cfg.Sections() {
        if isValidUUID4(section.Name()) {
            configs.AuthKeys[section.Name()] = &AuthKey{
                AuthKey:   cfg.Section(section.Name()).Key("auth_key").String(),
                AuthKeyID: cfg.Section(section.Name()).Key("auth_key_id").String(),
            }
        }
    }

    return configs, nil
}

func getConfigFile() ([]byte, error) {
    if _, err := os.Stat(ConfigFilePath); err == nil {
        configBytes, err := ioutil.ReadFile(ConfigFilePath)
        if err != nil {
            return nil, err
        }
        return configBytes, nil
    } else if os.IsNotExist(err) {
        return nil, nil
    } else {
        return nil, err
    }
}

func isValidUUID4(uuid string) bool {
    r := regexp.MustCompile("^[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-4[a-fA-F0-9]{3}-[8|9|aA|bB][a-fA-F0-9]{3}-[a-fA-F0-9]{12}$")
    return r.MatchString(uuid)
}