code.dwrz.net

request.go (5352B)

---

 package http
 
 import (
 	"context"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"net/http"
 	"net/url"
 	"strings"
 
 	iointernal "github.com/aws/smithy-go/transport/http/internal/io"
 )
 
 // Request provides the HTTP specific request structure for HTTP specific
 // middleware steps to use to serialize input, and send an operation's request.
 type Request struct {
 	*http.Request
 	stream           io.Reader
 	isStreamSeekable bool
 	streamStartPos   int64
 }
 
 // NewStackRequest returns an initialized request ready to be populated with the
 // HTTP request details. Returns empty interface so the function can be used as
 // a parameter to the Smithy middleware Stack constructor.
 func NewStackRequest() interface{} {
 	return &Request{
 		Request: &http.Request{
 			URL:           &url.URL{},
 			Header:        http.Header{},
 			ContentLength: -1, // default to unknown length
 		},
 	}
 }
 
 // IsHTTPS returns if the request is HTTPS. Returns false if no endpoint URL is set.
 func (r *Request) IsHTTPS() bool {
 	if r.URL == nil {
 		return false
 	}
 	return strings.EqualFold(r.URL.Scheme, "https")
 }
 
 // Clone returns a deep copy of the Request for the new context. A reference to
 // the Stream is copied, but the underlying stream is not copied.
 func (r *Request) Clone() *Request {
 	rc := *r
 	rc.Request = rc.Request.Clone(context.TODO())
 	return &rc
 }
 
 // StreamLength returns the number of bytes of the serialized stream attached
 // to the request and ok set. If the length cannot be determined, an error will
 // be returned.
 func (r *Request) StreamLength() (size int64, ok bool, err error) {
 	return streamLength(r.stream, r.isStreamSeekable, r.streamStartPos)
 }
 
 func streamLength(stream io.Reader, seekable bool, startPos int64) (size int64, ok bool, err error) {
 	if stream == nil {
 		return 0, true, nil
 	}
 
 	if l, ok := stream.(interface{ Len() int }); ok {
 		return int64(l.Len()), true, nil
 	}
 
 	if !seekable {
 		return 0, false, nil
 	}
 
 	s := stream.(io.Seeker)
 	endOffset, err := s.Seek(0, io.SeekEnd)
 	if err != nil {
 		return 0, false, err
 	}
 
 	// The reason to seek to streamStartPos instead of 0 is to ensure that the
 	// SDK only sends the stream from the starting position the user's
 	// application provided it to the SDK at. For example application opens a
 	// file, and wants to skip the first N bytes uploading the rest. The
 	// application would move the file's offset N bytes, then hand it off to
 	// the SDK to send the remaining. The SDK should respect that initial offset.
 	_, err = s.Seek(startPos, io.SeekStart)
 	if err != nil {
 		return 0, false, err
 	}
 
 	return endOffset - startPos, true, nil
 }
 
 // RewindStream will rewind the io.Reader to the relative start position if it
 // is an io.Seeker.
 func (r *Request) RewindStream() error {
 	// If there is no stream there is nothing to rewind.
 	if r.stream == nil {
 		return nil
 	}
 
 	if !r.isStreamSeekable {
 		return fmt.Errorf("request stream is not seekable")
 	}
 	_, err := r.stream.(io.Seeker).Seek(r.streamStartPos, io.SeekStart)
 	return err
 }
 
 // GetStream returns the request stream io.Reader if a stream is set. If no
 // stream is present nil will be returned.
 func (r *Request) GetStream() io.Reader {
 	return r.stream
 }
 
 // IsStreamSeekable returns whether the stream is seekable.
 func (r *Request) IsStreamSeekable() bool {
 	return r.isStreamSeekable
 }
 
 // SetStream returns a clone of the request with the stream set to the provided
 // reader. May return an error if the provided reader is seekable but returns
 // an error.
 func (r *Request) SetStream(reader io.Reader) (rc *Request, err error) {
 	rc = r.Clone()
 
 	if reader == http.NoBody {
 		reader = nil
 	}
 
 	var isStreamSeekable bool
 	var streamStartPos int64
 	switch v := reader.(type) {
 	case io.Seeker:
 		n, err := v.Seek(0, io.SeekCurrent)
 		if err != nil {
 			return r, err
 		}
 		isStreamSeekable = true
 		streamStartPos = n
 	default:
 		// If the stream length can be determined, and is determined to be empty,
 		// use a nil stream to prevent confusion between empty vs not-empty
 		// streams.
 		length, ok, err := streamLength(reader, false, 0)
 		if err != nil {
 			return nil, err
 		} else if ok && length == 0 {
 			reader = nil
 		}
 	}
 
 	rc.stream = reader
 	rc.isStreamSeekable = isStreamSeekable
 	rc.streamStartPos = streamStartPos
 
 	return rc, err
 }
 
 // Build returns a build standard HTTP request value from the Smithy request.
 // The request's stream is wrapped in a safe container that allows it to be
 // reused for subsequent attempts.
 func (r *Request) Build(ctx context.Context) *http.Request {
 	req := r.Request.Clone(ctx)
 
 	if r.stream == nil && req.ContentLength == -1 {
 		req.ContentLength = 0
 	}
 
 	switch stream := r.stream.(type) {
 	case *io.PipeReader:
 		req.Body = ioutil.NopCloser(stream)
 		req.ContentLength = -1
 	default:
 		// HTTP Client Request must only have a non-nil body if the
 		// ContentLength is explicitly unknown (-1) or non-zero. The HTTP
 		// Client will interpret a non-nil body and ContentLength 0 as
 		// "unknown". This is unwanted behavior.
 		if req.ContentLength != 0 && r.stream != nil {
 			req.Body = iointernal.NewSafeReadCloser(ioutil.NopCloser(stream))
 		}
 	}
 
 	return req
 }
 
 // RequestCloner is a function that can take an input request type and clone the request
 // for use in a subsequent retry attempt.
 func RequestCloner(v interface{}) interface{} {
 	return v.(*Request).Clone()
 }