package engine import ( "bytes" "encoding/json" "fmt" "io" "strconv" "strings" ) type Env []string func (env *Env) Get(key string) (value string) { // FIXME: use Map() for _, kv := range *env { if strings.Index(kv, "=") == -1 { continue } parts := strings.SplitN(kv, "=", 2) if parts[0] != key { continue } if len(parts) < 2 { value = "" } else { value = parts[1] } } return } func (env *Env) Exists(key string) bool { _, exists := env.Map()[key] return exists } // Len returns the number of keys in the environment. // Note that len(env) might be different from env.Len(), // because the same key might be set multiple times. func (env *Env) Len() int { return len(env.Map()) } func (env *Env) Init(src *Env) { (*env) = make([]string, 0, len(*src)) for _, val := range *src { (*env) = append((*env), val) } } func (env *Env) GetBool(key string) (value bool) { s := strings.ToLower(strings.Trim(env.Get(key), " \t")) if s == "" || s == "0" || s == "no" || s == "false" || s == "none" { return false } return true } func (env *Env) SetBool(key string, value bool) { if value { env.Set(key, "1") } else { env.Set(key, "0") } } func (env *Env) GetInt(key string) int { return int(env.GetInt64(key)) } func (env *Env) GetInt64(key string) int64 { s := strings.Trim(env.Get(key), " \t") val, err := strconv.ParseInt(s, 10, 64) if err != nil { return 0 } return val } func (env *Env) SetInt(key string, value int) { env.Set(key, fmt.Sprintf("%d", value)) } func (env *Env) SetInt64(key string, value int64) { env.Set(key, fmt.Sprintf("%d", value)) } // Returns nil if key not found func (env *Env) GetList(key string) []string { sval := env.Get(key) if sval == "" { return nil } l := make([]string, 0, 1) if err := json.Unmarshal([]byte(sval), &l); err != nil { l = append(l, sval) } return l } func (env *Env) GetSubEnv(key string) *Env { sval := env.Get(key) if sval == "" { return nil } buf := bytes.NewBufferString(sval) var sub Env if err := sub.Decode(buf); err != nil { return nil } return &sub } func (env *Env) SetSubEnv(key string, sub *Env) error { var buf bytes.Buffer if err := sub.Encode(&buf); err != nil { return err } env.Set(key, string(buf.Bytes())) return nil } func (env *Env) GetJson(key string, iface interface{}) error { sval := env.Get(key) if sval == "" { return nil } return json.Unmarshal([]byte(sval), iface) } func (env *Env) SetJson(key string, value interface{}) error { sval, err := json.Marshal(value) if err != nil { return err } env.Set(key, string(sval)) return nil } func (env *Env) SetList(key string, value []string) error { return env.SetJson(key, value) } func (env *Env) Set(key, value string) { *env = append(*env, key+"="+value) } func NewDecoder(src io.Reader) *Decoder { return &Decoder{ json.NewDecoder(src), } } type Decoder struct { *json.Decoder } func (decoder *Decoder) Decode() (*Env, error) { m := make(map[string]interface{}) if err := decoder.Decoder.Decode(&m); err != nil { return nil, err } env := &Env{} for key, value := range m { env.SetAuto(key, value) } return env, nil } // DecodeEnv decodes `src` as a json dictionary, and adds // each decoded key-value pair to the environment. // // If `src` cannot be decoded as a json dictionary, an error // is returned. func (env *Env) Decode(src io.Reader) error { m := make(map[string]interface{}) if err := json.NewDecoder(src).Decode(&m); err != nil { return err } for k, v := range m { env.SetAuto(k, v) } return nil } func (env *Env) SetAuto(k string, v interface{}) { // FIXME: we fix-convert float values to int, because // encoding/json decodes integers to float64, but cannot encode them back. // (See http://golang.org/src/pkg/encoding/json/decode.go#L46) if fval, ok := v.(float64); ok { env.SetInt64(k, int64(fval)) } else if sval, ok := v.(string); ok { env.Set(k, sval) } else if val, err := json.Marshal(v); err == nil { env.Set(k, string(val)) } else { env.Set(k, fmt.Sprintf("%v", v)) } } func changeFloats(v interface{}) interface{} { switch v := v.(type) { case float64: return int(v) case map[string]interface{}: for key, val := range v { v[key] = changeFloats(val) } case []interface{}: for idx, val := range v { v[idx] = changeFloats(val) } } return v } func (env *Env) Encode(dst io.Writer) error { m := make(map[string]interface{}) for k, v := range env.Map() { var val interface{} if err := json.Unmarshal([]byte(v), &val); err == nil { // FIXME: we fix-convert float values to int, because // encoding/json decodes integers to float64, but cannot encode them back. // (See http://golang.org/src/pkg/encoding/json/decode.go#L46) m[k] = changeFloats(val) } else { m[k] = v } } if err := json.NewEncoder(dst).Encode(&m); err != nil { return err } return nil } func (env *Env) WriteTo(dst io.Writer) (n int64, err error) { // FIXME: return the number of bytes written to respect io.WriterTo return 0, env.Encode(dst) } func (env *Env) Import(src interface{}) (err error) { defer func() { if err != nil { err = fmt.Errorf("ImportEnv: %s", err) } }() var buf bytes.Buffer if err := json.NewEncoder(&buf).Encode(src); err != nil { return err } if err := env.Decode(&buf); err != nil { return err } return nil } func (env *Env) Map() map[string]string { m := make(map[string]string) for _, kv := range *env { parts := strings.SplitN(kv, "=", 2) m[parts[0]] = parts[1] } return m } // MultiMap returns a representation of env as a // map of string arrays, keyed by string. // This is the same structure as http headers for example, // which allow each key to have multiple values. func (env *Env) MultiMap() map[string][]string { m := make(map[string][]string) for _, kv := range *env { parts := strings.SplitN(kv, "=", 2) m[parts[0]] = append(m[parts[0]], parts[1]) } return m } // InitMultiMap removes all values in env, then initializes // new values from the contents of m. func (env *Env) InitMultiMap(m map[string][]string) { (*env) = make([]string, 0, len(m)) for k, vals := range m { for _, v := range vals { env.Set(k, v) } } }