From bd95447ca5381be8e9594e580129e73dc365e843 Mon Sep 17 00:00:00 2001
From: DarthSim <darthsim@gmail.com>
Date: Wed, 8 May 2019 20:51:39 +0600
Subject: [PATCH] Add development errors mode

---
 config.go             | 2 ++
 docs/configuration.md | 4 ++++
 server.go             | 7 ++++++-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/config.go b/config.go
index 6a842724..6df8f22b 100644
--- a/config.go
+++ b/config.go
@@ -169,6 +169,7 @@ type config struct {
 	UserAgent string
 
 	IgnoreSslVerification bool
+	DevelopmentErrorsMode bool
 
 	LocalFileSystemRoot string
 	S3Enabled           bool
@@ -293,6 +294,7 @@ func init() {
 	strEnvConfig(&conf.UserAgent, "IMGPROXY_USER_AGENT")
 
 	boolEnvConfig(&conf.IgnoreSslVerification, "IMGPROXY_IGNORE_SSL_VERIFICATION")
+	boolEnvConfig(&conf.DevelopmentErrorsMode, "IMGPROXY_DEVELOPMENT_ERRORS_MODE")
 
 	strEnvConfig(&conf.LocalFileSystemRoot, "IMGPROXY_LOCAL_FILESYSTEM_ROOT")
 
diff --git a/docs/configuration.md b/docs/configuration.md
index 10f2545f..76475bd1 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -61,6 +61,10 @@ When you use imgproxy in a development environment, it can be useful to ignore S
 
 * `IMGPROXY_IGNORE_SSL_VERIFICATION`: when true, disables SSL verification, so imgproxy can be used in a development environment with self-signed SSL certificates.
 
+Also you may want imgproxy to respond with the same error message that it writes to the log:
+
+* `IMGPROXY_DEVELOPMENT_ERRORS_MODE`: when true, imgproxy will respond with detailed error messages. Not recommended for production because some errors may contain stack trace.
+
 ### Compression
 
 * `IMGPROXY_QUALITY`: default quality of the resulting image, percentage. Default: `80`;
diff --git a/server.go b/server.go
index f8dbe00c..6749e816 100644
--- a/server.go
+++ b/server.go
@@ -175,7 +175,12 @@ func respondWithError(reqID string, rw http.ResponseWriter, err *imgproxyError)
 	logResponse(reqID, err.StatusCode, err.Message)
 
 	rw.WriteHeader(err.StatusCode)
-	rw.Write([]byte(err.PublicMessage))
+
+	if conf.DevelopmentErrorsMode {
+		rw.Write([]byte(err.Message))
+	} else {
+		rw.Write([]byte(err.PublicMessage))
+	}
 }
 
 func respondWithOptions(reqID string, rw http.ResponseWriter) {