updated error handling

response.go

@@ -30,31 +30,40 @@ type Output struct {
 }
 
 // PopulateFromHTTPResponse populates response based on HTTP response
-func (r *Response) PopulateFromHTTPResponse(res *http.Response) {
+func (r *Response) PopulateFromHTTPResponse(res *http.Response)(err error) {
 	body, err := ioutil.ReadAll(res.Body)
-	check(err)
+	if err != nil {
+		return
+	}
 
 	err = json.Unmarshal(body, &r)
-
-	check(err)
+	if err != nil {
+		return
+	}
 
 	// Get the output URL from the Location header
 	r.URL = res.Header.Get("Location")
+	return
 }
 
 // SaveAs downloads and saves the compressed PNG file
-func (r *Response) SaveAs(fn string) {
+func (r *Response) SaveAs(fn string) (err error) {
 	resp, err := http.Get(r.URL)
-	check(err)
+	if err != nil {
+		return
+	}
 
 	defer resp.Body.Close()
 
 	out, err := os.Create(fn)
-	check(err)
+	if err != nil {
+		return
+	}
 
 	defer out.Close()
 
-	io.Copy(out, resp.Body)
+	_, err = io.Copy(out, resp.Body)
+	return
 }
 
 // Print a line of statistics

tinypng.go

@@ -24,13 +24,18 @@ func ShrinkFn(apiKey string, inputFilename string) (Response, error) {
 // Shrink allows you to shrink a PNG file using an open file handle.
 func Shrink(apiKey string, inputFile *os.File) (Response, error) {
 	res, err := uploadPNG(apiKey, inputFile)
-	check(err)
+	if err != nil {
+		return Response{}, err
+	}
 
 	defer res.Body.Close()
 
 	var r Response
 
-	r.PopulateFromHTTPResponse(res)
+	err = r.PopulateFromHTTPResponse(res)
+	if err != nil {
+		return Response{}, err
+	}
 
 	if res.StatusCode == 201 {
 		return r, nil

tinypng/main.go

@@ -75,7 +75,11 @@ func main() {
 	}
 
 	// Download the compressed PNG
-	res.SaveAs(outputFilename)
+	err = res.SaveAs(outputFilename)
+	if err != nil {
+		fatalError(err.Error())
+	}
+
 }
 
 // Handle input