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package request
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"reflect"
"strings"
"time"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/awserr"
"github.com/aws/aws-sdk-go/aws/client/metadata"
"github.com/aws/aws-sdk-go/internal/sdkio"
)
const (
// ErrCodeSerialization is the serialization error code that is received
// during protocol unmarshaling.
ErrCodeSerialization = "SerializationError"
// ErrCodeRead is an error that is returned during HTTP reads.
ErrCodeRead = "ReadError"
// ErrCodeResponseTimeout is the connection timeout error that is received
// during body reads.
ErrCodeResponseTimeout = "ResponseTimeout"
// ErrCodeInvalidPresignExpire is returned when the expire time provided to
// presign is invalid
ErrCodeInvalidPresignExpire = "InvalidPresignExpireError"
// CanceledErrorCode is the error code that will be returned by an
// API request that was canceled. Requests given a aws.Context may
// return this error when canceled.
CanceledErrorCode = "RequestCanceled"
// ErrCodeRequestError is an error preventing the SDK from continuing to
// process the request.
ErrCodeRequestError = "RequestError"
)
// A Request is the service request to be made.
type Request struct {
Config aws.Config
ClientInfo metadata.ClientInfo
Handlers Handlers
Retryer
AttemptTime time.Time
Time time.Time
Operation *Operation
HTTPRequest *http.Request
HTTPResponse *http.Response
Body io.ReadSeeker
streamingBody io.ReadCloser
BodyStart int64 // offset from beginning of Body that the request body starts
Params interface{}
Error error
Data interface{}
RequestID string
RetryCount int
Retryable *bool
RetryDelay time.Duration
NotHoist bool
SignedHeaderVals http.Header
LastSignedAt time.Time
DisableFollowRedirects bool
// Additional API error codes that should be retried. IsErrorRetryable
// will consider these codes in addition to its built in cases.
RetryErrorCodes []string
// Additional API error codes that should be retried with throttle backoff
// delay. IsErrorThrottle will consider these codes in addition to its
// built in cases.
ThrottleErrorCodes []string
// A value greater than 0 instructs the request to be signed as Presigned URL
// You should not set this field directly. Instead use Request's
// Presign or PresignRequest methods.
ExpireTime time.Duration
context aws.Context
built bool
// Need to persist an intermediate body between the input Body and HTTP
// request body because the HTTP Client's transport can maintain a reference
// to the HTTP request's body after the client has returned. This value is
// safe to use concurrently and wrap the input Body for each HTTP request.
safeBody *offsetReader
}
// An Operation is the service API operation to be made.
type Operation struct {
Name string
HTTPMethod string
HTTPPath string
*Paginator
BeforePresignFn func(r *Request) error
}
// New returns a new Request pointer for the service API operation and
// parameters.
//
// A Retryer should be provided to direct how the request is retried. If
// Retryer is nil, a default no retry value will be used. You can use
// NoOpRetryer in the Client package to disable retry behavior directly.
//
// Params is any value of input parameters to be the request payload.
// Data is pointer value to an object which the request's response
// payload will be deserialized to.
func New(cfg aws.Config, clientInfo metadata.ClientInfo, handlers Handlers,
retryer Retryer, operation *Operation, params interface{}, data interface{}) *Request {
if retryer == nil {
retryer = noOpRetryer{}
}
method := operation.HTTPMethod
if method == "" {
method = "POST"
}
httpReq, _ := http.NewRequest(method, "", nil)
var err error
httpReq.URL, err = url.Parse(clientInfo.Endpoint)
if err != nil {
httpReq.URL = &url.URL{}
err = awserr.New("InvalidEndpointURL", "invalid endpoint uri", err)
}
if len(operation.HTTPPath) != 0 {
opHTTPPath := operation.HTTPPath
var opQueryString string
if idx := strings.Index(opHTTPPath, "?"); idx >= 0 {
opQueryString = opHTTPPath[idx+1:]
opHTTPPath = opHTTPPath[:idx]
}
if strings.HasSuffix(httpReq.URL.Path, "/") && strings.HasPrefix(opHTTPPath, "/") {
opHTTPPath = opHTTPPath[1:]
}
httpReq.URL.Path += opHTTPPath
httpReq.URL.RawQuery = opQueryString
}
r := &Request{
Config: cfg,
ClientInfo: clientInfo,
Handlers: handlers.Copy(),
Retryer: retryer,
Time: time.Now(),
ExpireTime: 0,
Operation: operation,
HTTPRequest: httpReq,
Body: nil,
Params: params,
Error: err,
Data: data,
}
r.SetBufferBody([]byte{})
return r
}
// A Option is a functional option that can augment or modify a request when
// using a WithContext API operation method.
type Option func(*Request)
// WithGetResponseHeader builds a request Option which will retrieve a single
// header value from the HTTP Response. If there are multiple values for the
// header key use WithGetResponseHeaders instead to access the http.Header
// map directly. The passed in val pointer must be non-nil.
//
// This Option can be used multiple times with a single API operation.
//
// var id2, versionID string
// svc.PutObjectWithContext(ctx, params,
// request.WithGetResponseHeader("x-amz-id-2", &id2),
// request.WithGetResponseHeader("x-amz-version-id", &versionID),
// )
func WithGetResponseHeader(key string, val *string) Option {
return func(r *Request) {
r.Handlers.Complete.PushBack(func(req *Request) {
*val = req.HTTPResponse.Header.Get(key)
})
}
}
// WithGetResponseHeaders builds a request Option which will retrieve the
// headers from the HTTP response and assign them to the passed in headers
// variable. The passed in headers pointer must be non-nil.
//
// var headers http.Header
// svc.PutObjectWithContext(ctx, params, request.WithGetResponseHeaders(&headers))
func WithGetResponseHeaders(headers *http.Header) Option {
return func(r *Request) {
r.Handlers.Complete.PushBack(func(req *Request) {
*headers = req.HTTPResponse.Header
})
}
}
// WithLogLevel is a request option that will set the request to use a specific
// log level when the request is made.
//
// svc.PutObjectWithContext(ctx, params, request.WithLogLevel(aws.LogDebugWithHTTPBody)
func WithLogLevel(l aws.LogLevelType) Option {
return func(r *Request) {
r.Config.LogLevel = aws.LogLevel(l)
}
}
// ApplyOptions will apply each option to the request calling them in the order
// the were provided.
func (r *Request) ApplyOptions(opts ...Option) {
for _, opt := range opts {
opt(r)
}
}
// Context will always returns a non-nil context. If Request does not have a
// context aws.BackgroundContext will be returned.
func (r *Request) Context() aws.Context {
if r.context != nil {
return r.context
}
return aws.BackgroundContext()
}
// SetContext adds a Context to the current request that can be used to cancel
// a in-flight request. The Context value must not be nil, or this method will
// panic.
//
// Unlike http.Request.WithContext, SetContext does not return a copy of the
// Request. It is not safe to use use a single Request value for multiple
// requests. A new Request should be created for each API operation request.
//
// Go 1.6 and below:
// The http.Request's Cancel field will be set to the Done() value of
// the context. This will overwrite the Cancel field's value.
//
// Go 1.7 and above:
// The http.Request.WithContext will be used to set the context on the underlying
// http.Request. This will create a shallow copy of the http.Request. The SDK
// may create sub contexts in the future for nested requests such as retries.
func (r *Request) SetContext(ctx aws.Context) {
if ctx == nil {
panic("context cannot be nil")
}
setRequestContext(r, ctx)
}
// WillRetry returns if the request's can be retried.
func (r *Request) WillRetry() bool {
if !aws.IsReaderSeekable(r.Body) && r.HTTPRequest.Body != NoBody {
return false
}
return r.Error != nil && aws.BoolValue(r.Retryable) && r.RetryCount < r.MaxRetries()
}
func fmtAttemptCount(retryCount, maxRetries int) string {
return fmt.Sprintf("attempt %v/%v", retryCount, maxRetries)
}
// ParamsFilled returns if the request's parameters have been populated
// and the parameters are valid. False is returned if no parameters are
// provided or invalid.
func (r *Request) ParamsFilled() bool {
return r.Params != nil && reflect.ValueOf(r.Params).Elem().IsValid()
}
// DataFilled returns true if the request's data for response deserialization
// target has been set and is a valid. False is returned if data is not
// set, or is invalid.
func (r *Request) DataFilled() bool {
return r.Data != nil && reflect.ValueOf(r.Data).Elem().IsValid()
}
// SetBufferBody will set the request's body bytes that will be sent to
// the service API.
func (r *Request) SetBufferBody(buf []byte) {
r.SetReaderBody(bytes.NewReader(buf))
}
// SetStringBody sets the body of the request to be backed by a string.
func (r *Request) SetStringBody(s string) {
r.SetReaderBody(strings.NewReader(s))
}
// SetReaderBody will set the request's body reader.
func (r *Request) SetReaderBody(reader io.ReadSeeker) {
r.Body = reader
if aws.IsReaderSeekable(reader) {
var err error
// Get the Bodies current offset so retries will start from the same
// initial position.
r.BodyStart, err = reader.Seek(0, sdkio.SeekCurrent)
if err != nil {
r.Error = awserr.New(ErrCodeSerialization,
"failed to determine start of request body", err)
return
}
}
r.ResetBody()
}
// SetStreamingBody set the reader to be used for the request that will stream
// bytes to the server. Request's Body must not be set to any reader.
func (r *Request) SetStreamingBody(reader io.ReadCloser) {
r.streamingBody = reader
r.SetReaderBody(aws.ReadSeekCloser(reader))
}
// Presign returns the request's signed URL. Error will be returned
// if the signing fails. The expire parameter is only used for presigned Amazon
// S3 API requests. All other AWS services will use a fixed expiration
// time of 15 minutes.
//
// It is invalid to create a presigned URL with a expire duration 0 or less. An
// error is returned if expire duration is 0 or less.
func (r *Request) Presign(expire time.Duration) (string, error) {
r = r.copy()
// Presign requires all headers be hoisted. There is no way to retrieve
// the signed headers not hoisted without this. Making the presigned URL
// useless.
r.NotHoist = false
u, _, err := getPresignedURL(r, expire)
return u, err
}
// PresignRequest behaves just like presign, with the addition of returning a
// set of headers that were signed. The expire parameter is only used for
// presigned Amazon S3 API requests. All other AWS services will use a fixed
// expiration time of 15 minutes.
//
// It is invalid to create a presigned URL with a expire duration 0 or less. An
// error is returned if expire duration is 0 or less.
//
// Returns the URL string for the API operation with signature in the query string,
// and the HTTP headers that were included in the signature. These headers must
// be included in any HTTP request made with the presigned URL.
//
// To prevent hoisting any headers to the query string set NotHoist to true on
// this Request value prior to calling PresignRequest.
func (r *Request) PresignRequest(expire time.Duration) (string, http.Header, error) {
r = r.copy()
return getPresignedURL(r, expire)
}
// IsPresigned returns true if the request represents a presigned API url.
func (r *Request) IsPresigned() bool {
return r.ExpireTime != 0
}
func getPresignedURL(r *Request, expire time.Duration) (string, http.Header, error) {
if expire <= 0 {
return "", nil, awserr.New(
ErrCodeInvalidPresignExpire,
"presigned URL requires an expire duration greater than 0",
nil,
)
}
r.ExpireTime = expire
if r.Operation.BeforePresignFn != nil {
if err := r.Operation.BeforePresignFn(r); err != nil {
return "", nil, err
}
}
if err := r.Sign(); err != nil {
return "", nil, err
}
return r.HTTPRequest.URL.String(), r.SignedHeaderVals, nil
}
const (
notRetrying = "not retrying"
)
func debugLogReqError(r *Request, stage, retryStr string, err error) {
if !r.Config.LogLevel.Matches(aws.LogDebugWithRequestErrors) {
return
}
r.Config.Logger.Log(fmt.Sprintf("DEBUG: %s %s/%s failed, %s, error %v",
stage, r.ClientInfo.ServiceName, r.Operation.Name, retryStr, err))
}
// Build will build the request's object so it can be signed and sent
// to the service. Build will also validate all the request's parameters.
// Any additional build Handlers set on this request will be run
// in the order they were set.
//
// The request will only be built once. Multiple calls to build will have
// no effect.
//
// If any Validate or Build errors occur the build will stop and the error
// which occurred will be returned.
func (r *Request) Build() error {
if !r.built {
r.Handlers.Validate.Run(r)
if r.Error != nil {
debugLogReqError(r, "Validate Request", notRetrying, r.Error)
return r.Error
}
r.Handlers.Build.Run(r)
if r.Error != nil {
debugLogReqError(r, "Build Request", notRetrying, r.Error)
return r.Error
}
r.built = true
}
return r.Error
}
// Sign will sign the request, returning error if errors are encountered.
//
// Sign will build the request prior to signing. All Sign Handlers will
// be executed in the order they were set.
func (r *Request) Sign() error {
r.Build()
if r.Error != nil {
debugLogReqError(r, "Build Request", notRetrying, r.Error)
return r.Error
}
SanitizeHostForHeader(r.HTTPRequest)
r.Handlers.Sign.Run(r)
return r.Error
}
func (r *Request) getNextRequestBody() (body io.ReadCloser, err error) {
if r.streamingBody != nil {
return r.streamingBody, nil
}
if r.safeBody != nil {
r.safeBody.Close()
}
r.safeBody, err = newOffsetReader(r.Body, r.BodyStart)
if err != nil {
return nil, awserr.New(ErrCodeSerialization,
"failed to get next request body reader", err)
}
// Go 1.8 tightened and clarified the rules code needs to use when building
// requests with the http package. Go 1.8 removed the automatic detection
// of if the Request.Body was empty, or actually had bytes in it. The SDK
// always sets the Request.Body even if it is empty and should not actually
// be sent. This is incorrect.
//
// Go 1.8 did add a http.NoBody value that the SDK can use to tell the http
// client that the request really should be sent without a body. The
// Request.Body cannot be set to nil, which is preferable, because the
// field is exported and could introduce nil pointer dereferences for users
// of the SDK if they used that field.
//
// Related golang/go#18257
l, err := aws.SeekerLen(r.Body)
if err != nil {
return nil, awserr.New(ErrCodeSerialization,
"failed to compute request body size", err)
}
if l == 0 {
body = NoBody
} else if l > 0 {
body = r.safeBody
} else {
// Hack to prevent sending bodies for methods where the body
// should be ignored by the server. Sending bodies on these
// methods without an associated ContentLength will cause the
// request to socket timeout because the server does not handle
// Transfer-Encoding: chunked bodies for these methods.
//
// This would only happen if a aws.ReaderSeekerCloser was used with
// a io.Reader that was not also an io.Seeker, or did not implement
// Len() method.
switch r.Operation.HTTPMethod {
case "GET", "HEAD", "DELETE":
body = NoBody
default:
body = r.safeBody
}
}
return body, nil
}
// GetBody will return an io.ReadSeeker of the Request's underlying
// input body with a concurrency safe wrapper.
func (r *Request) GetBody() io.ReadSeeker {
return r.safeBody
}
// Send will send the request, returning error if errors are encountered.
//
// Send will sign the request prior to sending. All Send Handlers will
// be executed in the order they were set.
//
// Canceling a request is non-deterministic. If a request has been canceled,
// then the transport will choose, randomly, one of the state channels during
// reads or getting the connection.
//
// readLoop() and getConn(req *Request, cm connectMethod)
// https://github.com/golang/go/blob/master/src/net/http/transport.go
//
// Send will not close the request.Request's body.
func (r *Request) Send() error {
defer func() {
// Ensure a non-nil HTTPResponse parameter is set to ensure handlers
// checking for HTTPResponse values, don't fail.
if r.HTTPResponse == nil {
r.HTTPResponse = &http.Response{
Header: http.Header{},
Body: ioutil.NopCloser(&bytes.Buffer{}),
}
}
// Regardless of success or failure of the request trigger the Complete
// request handlers.
r.Handlers.Complete.Run(r)
}()
if err := r.Error; err != nil {
return err
}
for {
r.Error = nil
r.AttemptTime = time.Now()
if err := r.Sign(); err != nil {
debugLogReqError(r, "Sign Request", notRetrying, err)
return err
}
if err := r.sendRequest(); err == nil {
return nil
}
r.Handlers.Retry.Run(r)
r.Handlers.AfterRetry.Run(r)
if r.Error != nil || !aws.BoolValue(r.Retryable) {
return r.Error
}
if err := r.prepareRetry(); err != nil {
r.Error = err
return err
}
}
}
func (r *Request) prepareRetry() error {
if r.Config.LogLevel.Matches(aws.LogDebugWithRequestRetries) {
r.Config.Logger.Log(fmt.Sprintf("DEBUG: Retrying Request %s/%s, attempt %d",
r.ClientInfo.ServiceName, r.Operation.Name, r.RetryCount))
}
// The previous http.Request will have a reference to the r.Body
// and the HTTP Client's Transport may still be reading from
// the request's body even though the Client's Do returned.
r.HTTPRequest = copyHTTPRequest(r.HTTPRequest, nil)
r.ResetBody()
if err := r.Error; err != nil {
return awserr.New(ErrCodeSerialization,
"failed to prepare body for retry", err)
}
// Closing response body to ensure that no response body is leaked
// between retry attempts.
if r.HTTPResponse != nil && r.HTTPResponse.Body != nil {
r.HTTPResponse.Body.Close()
}
return nil
}
func (r *Request) sendRequest() (sendErr error) {
defer r.Handlers.CompleteAttempt.Run(r)
r.Retryable = nil
r.Handlers.Send.Run(r)
if r.Error != nil {
debugLogReqError(r, "Send Request",
fmtAttemptCount(r.RetryCount, r.MaxRetries()),
r.Error)
return r.Error
}
r.Handlers.UnmarshalMeta.Run(r)
r.Handlers.ValidateResponse.Run(r)
if r.Error != nil {
r.Handlers.UnmarshalError.Run(r)
debugLogReqError(r, "Validate Response",
fmtAttemptCount(r.RetryCount, r.MaxRetries()),
r.Error)
return r.Error
}
r.Handlers.Unmarshal.Run(r)
if r.Error != nil {
debugLogReqError(r, "Unmarshal Response",
fmtAttemptCount(r.RetryCount, r.MaxRetries()),
r.Error)
return r.Error
}
return nil
}
// copy will copy a request which will allow for local manipulation of the
// request.
func (r *Request) copy() *Request {
req := &Request{}
*req = *r
req.Handlers = r.Handlers.Copy()
op := *r.Operation
req.Operation = &op
return req
}
// AddToUserAgent adds the string to the end of the request's current user agent.
func AddToUserAgent(r *Request, s string) {
curUA := r.HTTPRequest.Header.Get("User-Agent")
if len(curUA) > 0 {
s = curUA + " " + s
}
r.HTTPRequest.Header.Set("User-Agent", s)
}
// SanitizeHostForHeader removes default port from host and updates request.Host
func SanitizeHostForHeader(r *http.Request) {
host := getHost(r)
port := portOnly(host)
if port != "" && isDefaultPort(r.URL.Scheme, port) {
r.Host = stripPort(host)
}
}
// Returns host from request
func getHost(r *http.Request) string {
if r.Host != "" {
return r.Host
}
if r.URL == nil {
return ""
}
return r.URL.Host
}
// Hostname returns u.Host, without any port number.
//
// If Host is an IPv6 literal with a port number, Hostname returns the
// IPv6 literal without the square brackets. IPv6 literals may include
// a zone identifier.
//
// Copied from the Go 1.8 standard library (net/url)
func stripPort(hostport string) string {
colon := strings.IndexByte(hostport, ':')
if colon == -1 {
return hostport
}
if i := strings.IndexByte(hostport, ']'); i != -1 {
return strings.TrimPrefix(hostport[:i], "[")
}
return hostport[:colon]
}
// Port returns the port part of u.Host, without the leading colon.
// If u.Host doesn't contain a port, Port returns an empty string.
//
// Copied from the Go 1.8 standard library (net/url)
func portOnly(hostport string) string {
colon := strings.IndexByte(hostport, ':')
if colon == -1 {
return ""
}
if i := strings.Index(hostport, "]:"); i != -1 {
return hostport[i+len("]:"):]
}
if strings.Contains(hostport, "]") {
return ""
}
return hostport[colon+len(":"):]
}
// Returns true if the specified URI is using the standard port
// (i.e. port 80 for HTTP URIs or 443 for HTTPS URIs)
func isDefaultPort(scheme, port string) bool {
if port == "" {
return true
}
lowerCaseScheme := strings.ToLower(scheme)
if (lowerCaseScheme == "http" && port == "80") || (lowerCaseScheme == "https" && port == "443") {
return true
}
return false
}
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