request.go

package commands

import (
	"fmt"
	"io"
	"os"
	"reflect"
	"strconv"
	"time"

	"golang.org/x/net/context"

	"github.com/ipfs/go-commands/files"
	"github.com/ipfs/go-commands/util"
)

type OptMap map[string]interface{}

// Request represents a call to a command from a consumer
type Request interface {
	Path() []string
	Option(name string) *OptionValue
	Options() OptMap
	SetOption(name string, val interface{})
	SetOptions(opts OptMap) error
	Arguments() []string
	SetArguments([]string)
	Files() files.File
	SetFiles(files.File)
	Context() context.Context
	SetRootContext(context.Context) error
	Command() *Command
	Values() map[string]interface{}
	Stdin() io.Reader

	ConvertOptions() error
}

type request struct {
	path       []string
	options    OptMap
	arguments  []string
	files      files.File
	cmd        *Command
	rctx       context.Context
	optionDefs map[string]Option
	values     map[string]interface{}
	stdin      io.Reader
}

// Path returns the command path of this request
func (r *request) Path() []string {
	return r.path
}

// Option returns the value of the option for given name.
func (r *request) Option(name string) *OptionValue {
	// find the option with the specified name
	option, found := r.optionDefs[name]
	if !found {
		return nil
	}

	// try all the possible names, break if we find a value
	for _, n := range option.Names() {
		val, found := r.options[n]
		if found {
			return &OptionValue{val, found, option}
		}
	}

	// MAYBE_TODO: use default value instead of nil
	return &OptionValue{nil, false, option}
}

// Options returns a copy of the option map
func (r *request) Options() OptMap {
	output := make(OptMap)
	for k, v := range r.options {
		output[k] = v
	}
	return output
}

func (r *request) SetRootContext(ctx context.Context) error {
	ctx, err := getContext(ctx, r)
	if err != nil {
		return err
	}

	r.rctx = ctx
	return nil
}

// SetOption sets the value of the option for given name.
func (r *request) SetOption(name string, val interface{}) {
	// find the option with the specified name
	option, found := r.optionDefs[name]
	if !found {
		return
	}

	// try all the possible names, if we already have a value then set over it
	for _, n := range option.Names() {
		_, found := r.options[n]
		if found {
			r.options[n] = val
			return
		}
	}

	r.options[name] = val
}

// SetOptions sets the option values, unsetting any values that were previously set
func (r *request) SetOptions(opts OptMap) error {
	r.options = opts
	return r.ConvertOptions()
}

// Arguments returns the arguments slice
func (r *request) Arguments() []string {
	return r.arguments
}

func (r *request) SetArguments(args []string) {
	r.arguments = args
}

func (r *request) Files() files.File {
	return r.files
}

func (r *request) SetFiles(f files.File) {
	r.files = f
}

func (r *request) Context() context.Context {
	return r.rctx
}

func getContext(base context.Context, req Request) (context.Context, error) {
	tout, found, err := req.Option("timeout").String()
	if err != nil {
		return nil, fmt.Errorf("error parsing timeout option: %s", err)
	}

	var ctx context.Context
	if found {
		duration, err := time.ParseDuration(tout)
		if err != nil {
			return nil, fmt.Errorf("error parsing timeout option: %s", err)
		}

		tctx, _ := context.WithTimeout(base, duration)
		ctx = tctx
	} else {
		cctx, _ := context.WithCancel(base)
		ctx = cctx
	}
	return ctx, nil
}

func (r *request) Command() *Command {
	return r.cmd
}

type converter func(string) (interface{}, error)

var converters = map[reflect.Kind]converter{
	Bool: func(v string) (interface{}, error) {
		if v == "" {
			return true, nil
		}
		return strconv.ParseBool(v)
	},
	Int: func(v string) (interface{}, error) {
		val, err := strconv.ParseInt(v, 0, 32)
		if err != nil {
			return nil, err
		}
		return int(val), err
	},
	Uint: func(v string) (interface{}, error) {
		val, err := strconv.ParseUint(v, 0, 32)
		if err != nil {
			return nil, err
		}
		return int(val), err
	},
	Float: func(v string) (interface{}, error) {
		return strconv.ParseFloat(v, 64)
	},
}

func (r *request) Values() map[string]interface{} {
	return r.values
}

func (r *request) Stdin() io.Reader {
	return r.stdin
}

func (r *request) ConvertOptions() error {
	for k, v := range r.options {
		opt, ok := r.optionDefs[k]
		if !ok {
			continue
		}

		kind := reflect.TypeOf(v).Kind()
		if kind != opt.Type() {
			if kind == String {
				convert := converters[opt.Type()]
				str, ok := v.(string)
				if !ok {
					return util.ErrCast()
				}
				val, err := convert(str)
				if err != nil {
					value := fmt.Sprintf("value '%v'", v)
					if len(str) == 0 {
						value = "empty value"
					}
					return fmt.Errorf("Could not convert %s to type '%s' (for option '-%s')",
						value, opt.Type().String(), k)
				}
				r.options[k] = val

			} else {
				return fmt.Errorf("Option '%s' should be type '%s', but got type '%s'",
					k, opt.Type().String(), kind.String())
			}
		} else {
			r.options[k] = v
		}

		for _, name := range opt.Names() {
			if _, ok := r.options[name]; name != k && ok {
				return fmt.Errorf("Duplicate command options were provided ('%s' and '%s')",
					k, name)
			}
		}
	}

	return nil
}

// NewEmptyRequest initializes an empty request
func NewEmptyRequest() (Request, error) {
	return NewRequest(nil, nil, nil, nil, nil, nil)
}

// NewRequest returns a request initialized with given arguments
// An non-nil error will be returned if the provided option values are invalid
func NewRequest(path []string, opts OptMap, args []string, file files.File, cmd *Command, optDefs map[string]Option) (Request, error) {
	if opts == nil {
		opts = make(OptMap)
	}
	if optDefs == nil {
		optDefs = make(map[string]Option)
	}

	values := make(map[string]interface{})
	req := &request{
		path:       path,
		options:    opts,
		arguments:  args,
		files:      file,
		cmd:        cmd,
		optionDefs: optDefs,
		values:     values,
		stdin:      os.Stdin,
	}
	err := req.ConvertOptions()
	if err != nil {
		return nil, err
	}

	return req, nil
}