Add Get* methods to Payload type

payload.go

@@ -0,0 +1,155 @@
+package asynq
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/spf13/cast"
+)
+
+// Payload is an arbitrary data needed for task execution.
+// The values have to be JSON serializable.
+type Payload map[string]interface{}
+
+type errKeyNotFound struct {
+	key string
+}
+
+func (e *errKeyNotFound) Error() string {
+	return fmt.Sprintf("key %q does not exist", e.key)
+}
+
+// GetString returns a string value if a string type is associated with
+// the key, otherwise reports an error.
+func (p Payload) GetString(key string) (string, error) {
+	v, ok := p[key]
+	if !ok {
+		return "", &errKeyNotFound{key}
+	}
+	return cast.ToStringE(v)
+}
+
+// GetInt returns an int value if a numeric type is associated with
+// the key, otherwise reports an error.
+func (p Payload) GetInt(key string) (int, error) {
+	v, ok := p[key]
+	if !ok {
+		return 0, &errKeyNotFound{key}
+	}
+	return cast.ToIntE(v)
+}
+
+// GetFloat64 returns a float64 value if a numeric type is associated with
+// the key, otherwise reports an error.
+func (p Payload) GetFloat64(key string) (float64, error) {
+	v, ok := p[key]
+	if !ok {
+		return 0, &errKeyNotFound{key}
+	}
+	return cast.ToFloat64E(v)
+}
+
+// GetBool returns a boolean value if a boolean type is associated with
+// the key, otherwise reports an error.
+func (p Payload) GetBool(key string) (bool, error) {
+	v, ok := p[key]
+	if !ok {
+		return false, &errKeyNotFound{key}
+	}
+	return cast.ToBoolE(v)
+}
+
+// GetStringSlice returns a slice of strings if a string slice type is associated with
+// the key, otherwise reports an error.
+func (p Payload) GetStringSlice(key string) ([]string, error) {
+	v, ok := p[key]
+	if !ok {
+		return nil, &errKeyNotFound{key}
+	}
+	return cast.ToStringSliceE(v)
+}
+
+// GetIntSlice returns a slice of ints if a int slice type is associated with
+// the key, otherwise reports an error.
+func (p Payload) GetIntSlice(key string) ([]int, error) {
+	v, ok := p[key]
+	if !ok {
+		return nil, &errKeyNotFound{key}
+	}
+	return cast.ToIntSliceE(v)
+}
+
+// GetStringMap returns a map of string to empty interface
+// if a correct map type is associated with the key,
+// otherwise reports an error.
+func (p Payload) GetStringMap(key string) (map[string]interface{}, error) {
+	v, ok := p[key]
+	if !ok {
+		return nil, &errKeyNotFound{key}
+	}
+	return cast.ToStringMapE(v)
+}
+
+// GetStringMapString returns a map of string to string
+// if a correct map type is associated with the key,
+// otherwise reports an error.
+func (p Payload) GetStringMapString(key string) (map[string]string, error) {
+	v, ok := p[key]
+	if !ok {
+		return nil, &errKeyNotFound{key}
+	}
+	return cast.ToStringMapStringE(v)
+}
+
+// GetStringMapStringSlice returns a map of string to string slice
+// if a correct map type is associated with the key,
+// otherwise reports an error.
+func (p Payload) GetStringMapStringSlice(key string) (map[string][]string, error) {
+	v, ok := p[key]
+	if !ok {
+		return nil, &errKeyNotFound{key}
+	}
+	return cast.ToStringMapStringSliceE(v)
+}
+
+// GetStringMapInt returns a map of string to int
+// if a correct map type is associated with the key,
+// otherwise reports an error.
+func (p Payload) GetStringMapInt(key string) (map[string]int, error) {
+	v, ok := p[key]
+	if !ok {
+		return nil, &errKeyNotFound{key}
+	}
+	return cast.ToStringMapIntE(v)
+}
+
+// GetStringMapBool returns a map of string to boolean
+// if a correct map type is associated with the key,
+// otherwise reports an error.
+func (p Payload) GetStringMapBool(key string) (map[string]bool, error) {
+	v, ok := p[key]
+	if !ok {
+		return nil, &errKeyNotFound{key}
+	}
+	return cast.ToStringMapBoolE(v)
+}
+
+// GetTime returns a time value if a correct map type is associated with the key,
+// otherwise reports an error.
+func (p Payload) GetTime(key string) (time.Time, error) {
+	v, ok := p[key]
+	if !ok {
+		return time.Time{}, &errKeyNotFound{key}
+	}
+	return cast.ToTimeE(v)
+}
+
+// GetDuration returns a duration value if a correct map type is associated with the key,
+// otherwise reports an error.
+func (p Payload) GetDuration(key string) (time.Duration, error) {
+	v, ok := p[key]
+	if !ok {
+		return 0, &errKeyNotFound{key}
+	}
+	return cast.ToDurationE(v)
+}