Initial commit

server/internal/httpapi/response.go

@@ -0,0 +1,73 @@
+package httpapi
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"io"
+	"net/http"
+)
+
+const maxJSONBody = 1 << 20
+
+type apiError struct {
+	Status  int
+	Code    string
+	Message string
+	Details any
+}
+
+func (e *apiError) Error() string { return e.Code + ": " + e.Message }
+
+func writeJSON(w http.ResponseWriter, status int, value any) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(value)
+}
+
+func writeError(w http.ResponseWriter, err error) {
+	var target *apiError
+	if !errors.As(err, &target) {
+		target = &apiError{Status: http.StatusInternalServerError, Code: "INTERNAL_ERROR", Message: "服务暂时不可用"}
+	}
+	body := map[string]any{
+		"error": map[string]any{
+			"code":    target.Code,
+			"message": target.Message,
+		},
+	}
+	if target.Details != nil {
+		body["error"].(map[string]any)["details"] = target.Details
+	}
+	writeJSON(w, target.Status, body)
+}
+
+func decodeJSON(r *http.Request, dst any) error {
+	decoder := json.NewDecoder(io.LimitReader(r.Body, maxJSONBody))
+	decoder.DisallowUnknownFields()
+	if err := decoder.Decode(dst); err != nil {
+		return &apiError{Status: http.StatusBadRequest, Code: "INVALID_JSON", Message: "请求内容格式不正确"}
+	}
+	if err := decoder.Decode(&struct{}{}); !errors.Is(err, io.EOF) {
+		return &apiError{Status: http.StatusBadRequest, Code: "INVALID_JSON", Message: "请求只能包含一个 JSON 对象"}
+	}
+	return nil
+}
+
+func marshalResponse(value any) ([]byte, error) {
+	body, err := json.Marshal(value)
+	if err != nil {
+		return nil, err
+	}
+	return body, nil
+}
+
+func requestHash(value any) (string, error) {
+	body, err := json.Marshal(value)
+	if err != nil {
+		return "", err
+	}
+	sum := sha256.Sum256(body)
+	return hex.EncodeToString(sum[:]), nil
+}