Documentation
¶
Overview ¶
Package v4 implements signing for AWS V4 signer
Provides request signing for request that need to be signed with AWS V4 Signatures.
Standalone Signer ¶
Generally using the signer outside of the SDK should not require any additional
The signer does this by taking advantage of the URL.EscapedPath method. If your request URI requires
additional escaping you many need to use the URL.Opaque to define what the raw URI should be sent to the service as.
The signer will first check the URL.Opaque field, and use its value if set. The signer does require the URL.Opaque field to be set in the form of:
"//<hostname>/<path>" // e.g. "//example.com/some/path"
The leading "//" and hostname are required or the URL.Opaque escaping will not work correctly.
If URL.Opaque is not set the signer will fallback to the URL.EscapedPath() method and using the returned value.
AWS v4 signature validation requires that the canonical string's URI path element must be the URI escaped form of the HTTP request's path. http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
The Go HTTP client will perform escaping automatically on the request. Some of these escaping may cause signature validation errors because the HTTP request differs from the URI path or query that the signature was generated. https://golang.org/pkg/net/url/#URL.EscapedPath
Because of this, it is recommended that when using the signer outside of the SDK that explicitly escaping the request prior to being signed is preferable, and will help prevent signature validation errors. This can be done by setting the URL.Opaque or URL.RawPath. The SDK will use URL.Opaque first and then call URL.EscapedPath() if Opaque is not set.
Test `TestStandaloneSign` provides a complete example of using the signer outside of the SDK and pre-escaping the URI path.
Index ¶
Constants ¶
const (
// Version of signing v4
Version = "SigV4"
)
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type HTTPSigner ¶
type HTTPSigner interface {
SignHTTP(ctx context.Context, credentials aws.Credentials, r *http.Request, payloadHash string, service string, region string, signingTime time.Time, optFns ...func(*SignerOptions)) error
}
HTTPSigner is an interface to a SigV4 signer that can sign HTTP requests
type Signer ¶
type Signer struct {
// contains filtered or unexported fields
}
Signer applies AWS v4 signing to given request. Use this to sign requests that need to be signed with AWS V4 Signatures.
func NewSigner ¶
func NewSigner(optFns ...func(signer *SignerOptions)) *Signer
NewSigner returns a new SigV4 Signer
func (*Signer) PresignHTTP ¶
func (s *Signer) PresignHTTP( ctx context.Context, credentials aws.Credentials, r *http.Request, payloadHash string, service string, region string, signingTime time.Time, signedHdrs []string, optFns ...func(*SignerOptions), ) (signedURI string, signedHeaders http.Header, err error)
PresignHTTP signs AWS v4 requests with the payload hash, service name, region the request is made to, and time the request is signed at. The signTime allows you to specify that a request is signed for the future, and cannot be used until then.
Returns the signed URL and the map of HTTP headers that were included in the signature or an error if signing the request failed. For presigned requests these headers and their values must be included on the HTTP request when it is made. This is helpful to know what header values need to be shared with the party the presigned request will be distributed to.
The payloadHash is the hex encoded SHA-256 hash of the request payload, and must be provided. Even if the request has no payload (aka body). If the request has no payload you should use the hex encoded SHA-256 of an empty string as the payloadHash value.
"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
Some services such as Amazon S3 accept alternative values for the payload hash, such as "UNSIGNED-PAYLOAD" for requests where the body will not be included in the request signature.
https://docs.aws.amazon.com/AmazonS3/latest/API/sig-v4-header-based-auth.html
PresignHTTP differs from SignHTTP in that it will sign the request using query string instead of header values. This allows you to share the Presigned Request's URL with third parties, or distribute it throughout your system with minimal dependencies.
PresignHTTP will not set the expires time of the presigned request automatically. To specify the expire duration for a request add the "X-Amz-Expires" query parameter on the request with the value as the duration in seconds the presigned URL should be considered valid for. This parameter is not used by all AWS services, and is most notable used by Amazon S3 APIs.
expires := 20 * time.Minute
query := req.URL.Query()
query.Set("X-Amz-Expires", strconv.FormatInt(int64(expires/time.Second), 10))
req.URL.RawQuery = query.Encode()
This method does not modify the provided request.
func (Signer) SignHTTP ¶
func (s Signer) SignHTTP(ctx context.Context, credentials aws.Credentials, r *http.Request, payloadHash string, service string, region string, signingTime time.Time, signedHdrs []string, optFns ...func(options *SignerOptions)) error
SignHTTP signs AWS v4 requests with the provided payload hash, service name, region the request is made to, and time the request is signed at. The signTime allows you to specify that a request is signed for the future, and cannot be used until then.
The payloadHash is the hex encoded SHA-256 hash of the request payload, and must be provided. Even if the request has no payload (aka body). If the request has no payload you should use the hex encoded SHA-256 of an empty string as the payloadHash value.
"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
Some services such as Amazon S3 accept alternative values for the payload hash, such as "UNSIGNED-PAYLOAD" for requests where the body will not be included in the request signature.
https://docs.aws.amazon.com/AmazonS3/latest/API/sig-v4-header-based-auth.html
Sign differs from Presign in that it will sign the request using HTTP header values. This type of signing is intended for http.Request values that will not be shared, or are shared in a way the header values on the request will not be lost.
The passed in request will be modified in place.
type SignerOptions ¶
type SignerOptions struct {
// Disables the Signer's moving HTTP header key/value pairs from the HTTP
// request header to the request's query string. This is most commonly used
// with pre-signed requests preventing headers from being added to the
// request's query string.
DisableHeaderHoisting bool
// Disables the automatic escaping of the URI path of the request for the
// siganture's canonical string's path. For services that do not need additional
// escaping then use this to disable the signer escaping the path.
//
// S3 is an example of a service that does not need additional escaping.
//
// http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
DisableURIPathEscaping bool
// The logger to send log messages to.
Logger logging.Logger
// Enable logging of signed requests.
// This will enable logging of the canonical request, the string to sign, and for presigning the subsequent
// presigned URL.
LogSigning bool
// Disables setting the session token on the request as part of signing
// through X-Amz-Security-Token. This is needed for variations of v4 that
// present the token elsewhere.
DisableSessionToken bool
}
SignerOptions is the SigV4 Signer options.
Source Files