feat: add Go API library

response.go

@@ -0,0 +1,56 @@
+package mijia
+
+import (
+	"bytes"
+	"compress/gzip"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+)
+
+const maxHTTPResponseBytes = 16 << 20
+
+func readHTTPResponse(response *http.Response) ([]byte, error) {
+	rawBody, err := readBounded(response.Body, maxHTTPResponseBytes)
+	if err != nil {
+		return nil, fmt.Errorf("read raw HTTP response: %w", err)
+	}
+	if !headerContainsToken(response.Header.Get("Content-Encoding"), "gzip") {
+		return rawBody, nil
+	}
+
+	reader, err := gzip.NewReader(bytes.NewReader(rawBody))
+	if err != nil {
+		return nil, fmt.Errorf("open gzip HTTP response: %w", err)
+	}
+	body, readErr := readBounded(reader, maxHTTPResponseBytes)
+	closeErr := reader.Close()
+	if readErr != nil {
+		return nil, fmt.Errorf("decompress gzip HTTP response: %w", readErr)
+	}
+	if closeErr != nil {
+		return nil, fmt.Errorf("close gzip HTTP response: %w", closeErr)
+	}
+	return body, nil
+}
+
+func readBounded(reader io.Reader, maximum int64) ([]byte, error) {
+	body, err := io.ReadAll(io.LimitReader(reader, maximum+1))
+	if err != nil {
+		return nil, err
+	}
+	if int64(len(body)) > maximum {
+		return nil, fmt.Errorf("response exceeds %d bytes", maximum)
+	}
+	return body, nil
+}
+
+func headerContainsToken(value, token string) bool {
+	for _, encoding := range strings.Split(value, ",") {
+		if strings.EqualFold(strings.TrimSpace(encoding), token) {
+			return true
+		}
+	}
+	return false
+}