292 lines
7.3 KiB
Go
292 lines
7.3 KiB
Go
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// Package rest provides RESTful serialization of AWS requests and responses.
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package rest
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import (
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"bytes"
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"encoding/base64"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"path"
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"reflect"
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"strconv"
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"strings"
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"time"
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"github.com/aws/aws-sdk-go/aws"
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"github.com/aws/aws-sdk-go/aws/awserr"
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"github.com/aws/aws-sdk-go/aws/request"
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"github.com/aws/aws-sdk-go/private/protocol"
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)
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// RFC822 returns an RFC822 formatted timestamp for AWS protocols
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const RFC822 = "Mon, 2 Jan 2006 15:04:05 GMT"
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// Whether the byte value can be sent without escaping in AWS URLs
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var noEscape [256]bool
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var errValueNotSet = fmt.Errorf("value not set")
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func init() {
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for i := 0; i < len(noEscape); i++ {
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// AWS expects every character except these to be escaped
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noEscape[i] = (i >= 'A' && i <= 'Z') ||
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(i >= 'a' && i <= 'z') ||
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(i >= '0' && i <= '9') ||
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i == '-' ||
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i == '.' ||
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i == '_' ||
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i == '~'
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}
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}
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// BuildHandler is a named request handler for building rest protocol requests
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var BuildHandler = request.NamedHandler{Name: "awssdk.rest.Build", Fn: Build}
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// Build builds the REST component of a service request.
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func Build(r *request.Request) {
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if r.ParamsFilled() {
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v := reflect.ValueOf(r.Params).Elem()
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buildLocationElements(r, v, false)
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buildBody(r, v)
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}
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}
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// BuildAsGET builds the REST component of a service request with the ability to hoist
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// data from the body.
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func BuildAsGET(r *request.Request) {
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if r.ParamsFilled() {
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v := reflect.ValueOf(r.Params).Elem()
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buildLocationElements(r, v, true)
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buildBody(r, v)
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}
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}
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func buildLocationElements(r *request.Request, v reflect.Value, buildGETQuery bool) {
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query := r.HTTPRequest.URL.Query()
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// Setup the raw path to match the base path pattern. This is needed
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// so that when the path is mutated a custom escaped version can be
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// stored in RawPath that will be used by the Go client.
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r.HTTPRequest.URL.RawPath = r.HTTPRequest.URL.Path
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for i := 0; i < v.NumField(); i++ {
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m := v.Field(i)
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if n := v.Type().Field(i).Name; n[0:1] == strings.ToLower(n[0:1]) {
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continue
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}
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if m.IsValid() {
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field := v.Type().Field(i)
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name := field.Tag.Get("locationName")
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if name == "" {
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name = field.Name
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}
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if kind := m.Kind(); kind == reflect.Ptr {
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m = m.Elem()
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} else if kind == reflect.Interface {
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if !m.Elem().IsValid() {
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continue
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}
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}
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if !m.IsValid() {
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continue
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}
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if field.Tag.Get("ignore") != "" {
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continue
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}
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var err error
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switch field.Tag.Get("location") {
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case "headers": // header maps
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err = buildHeaderMap(&r.HTTPRequest.Header, m, field.Tag)
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case "header":
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err = buildHeader(&r.HTTPRequest.Header, m, name, field.Tag)
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case "uri":
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err = buildURI(r.HTTPRequest.URL, m, name, field.Tag)
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case "querystring":
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err = buildQueryString(query, m, name, field.Tag)
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default:
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if buildGETQuery {
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err = buildQueryString(query, m, name, field.Tag)
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}
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}
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r.Error = err
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}
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if r.Error != nil {
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return
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}
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}
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r.HTTPRequest.URL.RawQuery = query.Encode()
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if !aws.BoolValue(r.Config.DisableRestProtocolURICleaning) {
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cleanPath(r.HTTPRequest.URL)
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}
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}
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func buildBody(r *request.Request, v reflect.Value) {
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if field, ok := v.Type().FieldByName("_"); ok {
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if payloadName := field.Tag.Get("payload"); payloadName != "" {
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pfield, _ := v.Type().FieldByName(payloadName)
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if ptag := pfield.Tag.Get("type"); ptag != "" && ptag != "structure" {
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payload := reflect.Indirect(v.FieldByName(payloadName))
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if payload.IsValid() && payload.Interface() != nil {
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switch reader := payload.Interface().(type) {
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case io.ReadSeeker:
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r.SetReaderBody(reader)
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case []byte:
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r.SetBufferBody(reader)
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case string:
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r.SetStringBody(reader)
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default:
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r.Error = awserr.New("SerializationError",
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"failed to encode REST request",
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fmt.Errorf("unknown payload type %s", payload.Type()))
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}
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}
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}
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}
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}
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}
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func buildHeader(header *http.Header, v reflect.Value, name string, tag reflect.StructTag) error {
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str, err := convertType(v, tag)
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if err == errValueNotSet {
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return nil
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} else if err != nil {
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return awserr.New("SerializationError", "failed to encode REST request", err)
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}
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header.Add(name, str)
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return nil
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}
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func buildHeaderMap(header *http.Header, v reflect.Value, tag reflect.StructTag) error {
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prefix := tag.Get("locationName")
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for _, key := range v.MapKeys() {
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str, err := convertType(v.MapIndex(key), tag)
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if err == errValueNotSet {
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continue
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} else if err != nil {
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return awserr.New("SerializationError", "failed to encode REST request", err)
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}
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header.Add(prefix+key.String(), str)
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}
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return nil
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}
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func buildURI(u *url.URL, v reflect.Value, name string, tag reflect.StructTag) error {
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value, err := convertType(v, tag)
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if err == errValueNotSet {
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return nil
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} else if err != nil {
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return awserr.New("SerializationError", "failed to encode REST request", err)
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}
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u.Path = strings.Replace(u.Path, "{"+name+"}", value, -1)
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u.Path = strings.Replace(u.Path, "{"+name+"+}", value, -1)
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u.RawPath = strings.Replace(u.RawPath, "{"+name+"}", EscapePath(value, true), -1)
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u.RawPath = strings.Replace(u.RawPath, "{"+name+"+}", EscapePath(value, false), -1)
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return nil
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}
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func buildQueryString(query url.Values, v reflect.Value, name string, tag reflect.StructTag) error {
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switch value := v.Interface().(type) {
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case []*string:
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for _, item := range value {
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query.Add(name, *item)
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}
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case map[string]*string:
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for key, item := range value {
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query.Add(key, *item)
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}
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case map[string][]*string:
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for key, items := range value {
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for _, item := range items {
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query.Add(key, *item)
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}
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}
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default:
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str, err := convertType(v, tag)
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if err == errValueNotSet {
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return nil
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} else if err != nil {
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return awserr.New("SerializationError", "failed to encode REST request", err)
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}
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query.Set(name, str)
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}
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return nil
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}
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func cleanPath(u *url.URL) {
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hasSlash := strings.HasSuffix(u.Path, "/")
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// clean up path, removing duplicate `/`
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u.Path = path.Clean(u.Path)
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u.RawPath = path.Clean(u.RawPath)
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if hasSlash && !strings.HasSuffix(u.Path, "/") {
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u.Path += "/"
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u.RawPath += "/"
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}
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}
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// EscapePath escapes part of a URL path in Amazon style
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func EscapePath(path string, encodeSep bool) string {
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var buf bytes.Buffer
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for i := 0; i < len(path); i++ {
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c := path[i]
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if noEscape[c] || (c == '/' && !encodeSep) {
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buf.WriteByte(c)
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} else {
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fmt.Fprintf(&buf, "%%%02X", c)
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}
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}
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return buf.String()
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}
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func convertType(v reflect.Value, tag reflect.StructTag) (str string, err error) {
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v = reflect.Indirect(v)
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if !v.IsValid() {
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return "", errValueNotSet
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}
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switch value := v.Interface().(type) {
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case string:
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str = value
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case []byte:
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str = base64.StdEncoding.EncodeToString(value)
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case bool:
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str = strconv.FormatBool(value)
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case int64:
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str = strconv.FormatInt(value, 10)
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case float64:
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str = strconv.FormatFloat(value, 'f', -1, 64)
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case time.Time:
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str = value.UTC().Format(RFC822)
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case aws.JSONValue:
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if len(value) == 0 {
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return "", errValueNotSet
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}
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escaping := protocol.NoEscape
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if tag.Get("location") == "header" {
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escaping = protocol.Base64Escape
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}
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str, err = protocol.EncodeJSONValue(value, escaping)
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if err != nil {
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return "", fmt.Errorf("unable to encode JSONValue, %v", err)
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}
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default:
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err := fmt.Errorf("unsupported value for param %v (%s)", v.Interface(), v.Type())
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return "", err
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}
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return str, nil
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}
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