fix: add support for compressed hydrator. Closes #988

pipeline/mutate/mutator_hydrator.go

@@ -22,9 +22,12 @@
 
 import (
 	"bytes"
+	"compress/gzip"
+	"compress/zlib"
 	"crypto/md5"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"net/url"
 	"time"
@@ -51,6 +54,8 @@
 	ErrNoCredentialsProvided            = "No credentials were provided in mutator configuration"
 	contentTypeHeaderKey                = "Content-Type"
 	contentTypeJSONHeaderValue          = "application/json"
+	acceptEncodingHeaderKey             = "Accept-Encoding"
+	acceptEncodingHeaderValue           = "gzip, deflate"
 )
 
 type MutatorHydrator struct {
@@ -188,6 +193,7 @@
 		req.SetBasicAuth(credentials.Username, credentials.Password)
 	}
 	req.Header.Set(contentTypeHeaderKey, contentTypeJSONHeaderValue)
+	req.Header.Set(acceptEncodingHeaderKey, acceptEncodingHeaderValue)
 
 	var client *http.Client
 
@@ -235,8 +241,21 @@
 		return errors.New(ErrNon200ResponseFromAPI)
 	}
 
+	// Handle compressed data
+	var reader io.ReadCloser
+	switch res.Header.Get("Content-Encoding") {
+	case "gzip":
+		reader, err = gzip.NewReader(res.Body)
+		defer reader.Close()
+	case "deflate":
+		reader, err = zlib.NewReader(res.Body)
+		defer reader.Close()
+	default:
+		reader = res.Body
+	}
+
 	sessionFromUpstream := authn.AuthenticationSession{}
-	err = json.NewDecoder(res.Body).Decode(&sessionFromUpstream)
+	err = json.NewDecoder(reader).Decode(&sessionFromUpstream)
 	if err != nil {
 		return errors.WithStack(err)
 	}