Extend the content type matching to include application/foo+json format

Author: IsaacG

cmd/cmd.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"regexp"
 	"strings"
 
 	"io"
@@ -23,6 +24,8 @@ var (
 	Out io.Writer
 	// Err is used to write errors.
 	Err io.Writer
+	// jsonContentTypeRe is used to match Content-Type which contains JSON.
+	jsonContentTypeRe = regexp.MustCompile(`^application/([[:alpha:]]+\+)?json$`)
 )
 
 const msgWelcomePleaseConfigure = `
@@ -77,7 +80,7 @@ func validateUserConfig(cfg *viper.Viper) error {
 // decodedAPIError decodes and returns the error message from the API response.
 // If the message is blank, it returns a fallback message with the status code.
 func decodedAPIError(resp *http.Response) error {
-	if contentType := resp.Header.Get("Content-Type"); contentType != "application/json" {
+	if contentType := resp.Header.Get("Content-Type"); !jsonContentTypeRe.MatchString(contentType) {
 		return fmt.Errorf(
 			"expected response with Content-Type \"application/json\" but got status %q with Content-Type %q",
 			resp.Status,

cmd/cmd_test.go

@@ -156,12 +156,19 @@ func TestDecodeErrorResponse(t *testing.T) {
 			response:    errorResponse("application/json", `{"error": {"message": "message"}}`),
 			wantMessage: "message",
 		},
+		{
+			response:    errorResponse("application/problem+json", `{"error": {"message": "new json format"}}`),
+			wantMessage: "new json format",
+		},
 		{
 			response:    errorResponse("application/json", `{"error": {}}`),
 			wantMessage: "unexpected API response: 418",
 		},
 	}
-	for _, tc := range testCases {
+	tc := testCases[0]
+	got := decodedAPIError(tc.response)
+	assert.Equal(t, tc.wantMessage, got.Error())
+	for _, tc = range testCases {
 		got := decodedAPIError(tc.response)
 		assert.Equal(t, tc.wantMessage, got.Error())
 	}