chore: 并入 iotlcm-app 历史到 app/（原提交 f40bda9）

app/server/utility/iot_excelize/writer.go

@@ -0,0 +1,47 @@
+package iot_excelize
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+
+	"github.com/gogf/gf/v2/errors/gerror"
+	"github.com/gogf/gf/v2/net/ghttp"
+	"github.com/xuri/excelize/v2"
+)
+
+// WriteHTTP writes an Excel workbook as an attachment to the current HTTP response.
+func WriteHTTP(ctx context.Context, f *excelize.File, fileName string) (err error) {
+	r := ghttp.RequestFromCtx(ctx)
+	if r == nil {
+		return gerror.New("当前上下文不是HTTP请求")
+	}
+	if fileName == "" {
+		fileName = "export"
+	}
+
+	writer := r.Response.Writer
+	writer.Header().Set("Content-Type", "application/octet-stream")
+	writer.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s.xlsx", url.QueryEscape(fileName)))
+	writer.Header().Set("Content-Transfer-Encoding", "binary")
+	writer.Header().Set("Access-Control-Expose-Headers", "Content-Disposition")
+
+	if err = f.Write(writer); err != nil {
+		return err
+	}
+	r.Response.Status = http.StatusOK
+	writer.Flush()
+	return nil
+}
+
+// ToReadSeeker serializes an Excel workbook into memory for secondary handling.
+func ToReadSeeker(f *excelize.File) (io.ReadSeeker, error) {
+	var buffer bytes.Buffer
+	if err := f.Write(&buffer); err != nil {
+		return nil, err
+	}
+	return bytes.NewReader(buffer.Bytes()), nil
+}