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package v4a
import (
"context"
"fmt"
awsmiddleware "github.com/aws/aws-sdk-go-v2/aws/middleware"
v4 "github.com/aws/aws-sdk-go-v2/aws/signer/v4"
internalauth "github.com/aws/aws-sdk-go-v2/internal/auth"
"github.com/aws/smithy-go/middleware"
smithyhttp "github.com/aws/smithy-go/transport/http"
"net/http"
"time"
)
// HTTPSigner is SigV4a HTTP signer implementation
type HTTPSigner interface {
SignHTTP(ctx context.Context, credentials Credentials, r *http.Request, payloadHash string, service string, regionSet []string, signingTime time.Time, optfns ...func(*SignerOptions)) error
}
// SignHTTPRequestMiddlewareOptions is the middleware options for constructing a SignHTTPRequestMiddleware.
type SignHTTPRequestMiddlewareOptions struct {
Credentials CredentialsProvider
Signer HTTPSigner
LogSigning bool
}
// SignHTTPRequestMiddleware is a middleware for signing an HTTP request using SigV4a.
type SignHTTPRequestMiddleware struct {
credentials CredentialsProvider
signer HTTPSigner
logSigning bool
}
// NewSignHTTPRequestMiddleware constructs a SignHTTPRequestMiddleware using the given SignHTTPRequestMiddlewareOptions.
func NewSignHTTPRequestMiddleware(options SignHTTPRequestMiddlewareOptions) *SignHTTPRequestMiddleware {
return &SignHTTPRequestMiddleware{
credentials: options.Credentials,
signer: options.Signer,
logSigning: options.LogSigning,
}
}
// ID the middleware identifier.
func (s *SignHTTPRequestMiddleware) ID() string {
return "Signing"
}
// HandleFinalize signs an HTTP request using SigV4a.
func (s *SignHTTPRequestMiddleware) HandleFinalize(
ctx context.Context, in middleware.FinalizeInput, next middleware.FinalizeHandler,
) (
out middleware.FinalizeOutput, metadata middleware.Metadata, err error,
) {
if !hasCredentialProvider(s.credentials) {
return next.HandleFinalize(ctx, in)
}
req, ok := in.Request.(*smithyhttp.Request)
if !ok {
return out, metadata, fmt.Errorf("unexpected request middleware type %T", in.Request)
}
signingName, signingRegion := awsmiddleware.GetSigningName(ctx), awsmiddleware.GetSigningRegion(ctx)
payloadHash := v4.GetPayloadHash(ctx)
if len(payloadHash) == 0 {
return out, metadata, &SigningError{Err: fmt.Errorf("computed payload hash missing from context")}
}
credentials, err := s.credentials.RetrievePrivateKey(ctx)
if err != nil {
return out, metadata, &SigningError{Err: fmt.Errorf("failed to retrieve credentials: %w", err)}
}
signerOptions := []func(o *SignerOptions){
func(o *SignerOptions) {
o.Logger = middleware.GetLogger(ctx)
o.LogSigning = s.logSigning
},
}
// existing DisableURIPathEscaping is equivalent in purpose
// to authentication scheme property DisableDoubleEncoding
disableDoubleEncoding, overridden := internalauth.GetDisableDoubleEncoding(ctx)
if overridden {
signerOptions = append(signerOptions, func(o *SignerOptions) {
o.DisableURIPathEscaping = disableDoubleEncoding
})
}
err = s.signer.SignHTTP(ctx, credentials, req.Request, payloadHash, signingName, []string{signingRegion}, time.Now().UTC(), signerOptions...)
if err != nil {
return out, metadata, &SigningError{Err: fmt.Errorf("failed to sign http request, %w", err)}
}
return next.HandleFinalize(ctx, in)
}
func hasCredentialProvider(p CredentialsProvider) bool {
if p == nil {
return false
}
return true
}
// RegisterSigningMiddleware registers the SigV4a signing middleware to the stack. If a signing middleware is already
// present, this provided middleware will be swapped. Otherwise the middleware will be added at the tail of the
// finalize step.
func RegisterSigningMiddleware(stack *middleware.Stack, signingMiddleware *SignHTTPRequestMiddleware) (err error) {
const signedID = "Signing"
_, present := stack.Finalize.Get(signedID)
if present {
_, err = stack.Finalize.Swap(signedID, signingMiddleware)
} else {
err = stack.Finalize.Add(signingMiddleware, middleware.After)
}
return err
}
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