rclone/fs/rc/params.go

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// Parameter parsing
package rc
import (
"encoding/json"
"errors"
"fmt"
"math"
"net/http"
"strconv"
"time"
"github.com/rclone/rclone/fs"
)
// Params is the input and output type for the Func
type Params map[string]interface{}
// ErrParamNotFound - this is returned from the Get* functions if the
// parameter isn't found along with a zero value of the requested
// item.
//
// Returning an error of this type from an rc.Func will cause the http
// method to return http.StatusBadRequest
type ErrParamNotFound string
// Error turns this error into a string
func (e ErrParamNotFound) Error() string {
return fmt.Sprintf("Didn't find key %q in input", string(e))
}
// IsErrParamNotFound returns whether err is ErrParamNotFound
func IsErrParamNotFound(err error) bool {
_, isNotFound := err.(ErrParamNotFound)
return isNotFound
}
// NotErrParamNotFound returns true if err != nil and
// !IsErrParamNotFound(err)
//
// This is for checking error returns of the Get* functions to ignore
// error not found returns and take the default value.
func NotErrParamNotFound(err error) bool {
return err != nil && !IsErrParamNotFound(err)
}
// ErrParamInvalid - this is returned from the Get* functions if the
// parameter is invalid.
//
//
// Returning an error of this type from an rc.Func will cause the http
// method to return http.StatusBadRequest
type ErrParamInvalid struct {
error
}
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// NewErrParamInvalid returns new ErrParamInvalid from given error
func NewErrParamInvalid(err error) ErrParamInvalid {
return ErrParamInvalid{err}
}
// IsErrParamInvalid returns whether err is ErrParamInvalid
func IsErrParamInvalid(err error) bool {
_, isInvalid := err.(ErrParamInvalid)
return isInvalid
}
// Reshape reshapes one blob of data into another via json serialization
//
// out should be a pointer type
//
// This isn't a very efficient way of dealing with this!
func Reshape(out interface{}, in interface{}) error {
b, err := json.Marshal(in)
if err != nil {
return fmt.Errorf("Reshape failed to Marshal: %w", err)
}
err = json.Unmarshal(b, out)
if err != nil {
return fmt.Errorf("Reshape failed to Unmarshal: %w", err)
}
return nil
}
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// Copy shallow copies the Params
func (p Params) Copy() (out Params) {
out = make(Params, len(p))
for k, v := range p {
out[k] = v
}
return out
}
// Get gets a parameter from the input
//
// If the parameter isn't found then error will be of type
// ErrParamNotFound and the returned value will be nil.
func (p Params) Get(key string) (interface{}, error) {
value, ok := p[key]
if !ok {
return nil, ErrParamNotFound(key)
}
return value, nil
}
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// GetHTTPRequest gets a http.Request parameter associated with the request with the key "_request"
//
// If the parameter isn't found then error will be of type
// ErrParamNotFound and the returned value will be nil.
func (p Params) GetHTTPRequest() (*http.Request, error) {
key := "_request"
value, err := p.Get(key)
if err != nil {
return nil, err
}
request, ok := value.(*http.Request)
if !ok {
return nil, ErrParamInvalid{fmt.Errorf("expecting http.request value for key %q (was %T)", key, value)}
}
return request, nil
}
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// GetHTTPResponseWriter gets a http.ResponseWriter parameter associated with the request with the key "_response"
//
// If the parameter isn't found then error will be of type
// ErrParamNotFound and the returned value will be nil.
func (p Params) GetHTTPResponseWriter() (http.ResponseWriter, error) {
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key := "_response"
value, err := p.Get(key)
if err != nil {
return nil, err
}
request, ok := value.(http.ResponseWriter)
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if !ok {
return nil, ErrParamInvalid{fmt.Errorf("expecting http.ResponseWriter value for key %q (was %T)", key, value)}
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}
return request, nil
}
// GetString gets a string parameter from the input
//
// If the parameter isn't found then error will be of type
// ErrParamNotFound and the returned value will be "".
func (p Params) GetString(key string) (string, error) {
value, err := p.Get(key)
if err != nil {
return "", err
}
str, ok := value.(string)
if !ok {
return "", ErrParamInvalid{fmt.Errorf("expecting string value for key %q (was %T)", key, value)}
}
return str, nil
}
// GetInt64 gets an int64 parameter from the input
//
// If the parameter isn't found then error will be of type
// ErrParamNotFound and the returned value will be 0.
func (p Params) GetInt64(key string) (int64, error) {
value, err := p.Get(key)
if err != nil {
return 0, err
}
switch x := value.(type) {
case int:
return int64(x), nil
case int64:
return x, nil
case float64:
if x > math.MaxInt64 || x < math.MinInt64 {
return 0, ErrParamInvalid{fmt.Errorf("key %q (%v) overflows int64 ", key, value)}
}
return int64(x), nil
case string:
i, err := strconv.ParseInt(x, 10, 0)
if err != nil {
return 0, ErrParamInvalid{fmt.Errorf("couldn't parse key %q (%v) as int64: %w", key, value, err)}
}
return i, nil
}
return 0, ErrParamInvalid{fmt.Errorf("expecting int64 value for key %q (was %T)", key, value)}
}
// GetFloat64 gets a float64 parameter from the input
//
// If the parameter isn't found then error will be of type
// ErrParamNotFound and the returned value will be 0.
func (p Params) GetFloat64(key string) (float64, error) {
value, err := p.Get(key)
if err != nil {
return 0, err
}
switch x := value.(type) {
case float64:
return x, nil
case int:
return float64(x), nil
case int64:
return float64(x), nil
case string:
f, err := strconv.ParseFloat(x, 64)
if err != nil {
return 0, ErrParamInvalid{fmt.Errorf("couldn't parse key %q (%v) as float64: %w", key, value, err)}
}
return f, nil
}
return 0, ErrParamInvalid{fmt.Errorf("expecting float64 value for key %q (was %T)", key, value)}
}
// GetBool gets a boolean parameter from the input
//
// If the parameter isn't found then error will be of type
// ErrParamNotFound and the returned value will be false.
func (p Params) GetBool(key string) (bool, error) {
value, err := p.Get(key)
if err != nil {
return false, err
}
switch x := value.(type) {
case int:
return x != 0, nil
case int64:
return x != 0, nil
case float64:
return x != 0, nil
case bool:
return x, nil
case string:
b, err := strconv.ParseBool(x)
if err != nil {
return false, ErrParamInvalid{fmt.Errorf("couldn't parse key %q (%v) as bool: %w", key, value, err)}
}
return b, nil
}
return false, ErrParamInvalid{fmt.Errorf("expecting bool value for key %q (was %T)", key, value)}
}
// GetStruct gets a struct from key from the input into the struct
// pointed to by out. out must be a pointer type.
//
// If the parameter isn't found then error will be of type
// ErrParamNotFound and out will be unchanged.
func (p Params) GetStruct(key string, out interface{}) error {
value, err := p.Get(key)
if err != nil {
return err
}
err = Reshape(out, value)
if err != nil {
if valueStr, ok := value.(string); ok {
// try to unmarshal as JSON if string
err = json.Unmarshal([]byte(valueStr), out)
if err == nil {
return nil
}
}
return ErrParamInvalid{fmt.Errorf("key %q: %w", key, err)}
}
return nil
}
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// GetStructMissingOK works like GetStruct but doesn't return an error
// if the key is missing
func (p Params) GetStructMissingOK(key string, out interface{}) error {
_, ok := p[key]
if !ok {
return nil
}
return p.GetStruct(key, out)
}
// GetDuration get the duration parameters from in
func (p Params) GetDuration(key string) (time.Duration, error) {
s, err := p.GetString(key)
if err != nil {
return 0, err
}
duration, err := fs.ParseDuration(s)
if err != nil {
return 0, ErrParamInvalid{fmt.Errorf("parse duration: %w", err)}
}
return duration, nil
}
// Error creates the standard response for an errored rc call using an
// rc.Param from a path, input Params, error and a suggested HTTP
// response code.
//
// It returns a Params and an updated status code
func Error(path string, in Params, err error, status int) (Params, int) {
// Adjust the status code for some well known errors
switch {
case errors.Is(err, fs.ErrorDirNotFound) || errors.Is(err, fs.ErrorObjectNotFound):
status = http.StatusNotFound
case IsErrParamInvalid(err) || IsErrParamNotFound(err):
status = http.StatusBadRequest
}
result := Params{
"status": status,
"error": err.Error(),
"input": in,
"path": path,
}
return result, status
}