README.md

Excel Exporter

excel-exporter is a Go package designed to simplify the process of exporting data to Excel files. It supports both in-memory and stream writing modes, making it efficient for handling large datasets. This package is built on top of the github.com/xuri/excelize/v2 package for robust Excel file manipulation.

Features

• Export data to Excel with support for multiple sheets.
• Efficient handling of large datasets using StreamWriter mode.
• Customizable cell styles, merged cells, and row options.
• Automatic handling of sheet row limits by creating new sheets.
• Built on top of the github.com/xuri/excelize/v2 package for robust Excel file manipulation.

Installation

To install the package, use:

go get -u github.com/xelarion/excel-exporter

Usage

Exporting Data

This example demonstrates how to use the StreamWriter mode to export a large dataset to an Excel file.

package main

import (
    "fmt"

    excelexporter "github.com/xelarion/excel-exporter"
)

func main() {
    // Set useStreamWriter to true for StreamWriter mode, false for in-memory mode
    useStreamWriter := true
    exporter := excelexporter.New("test_export.xlsx", useStreamWriter)
    sheets := []excelexporter.SheetData{
        {Name: "Sheet1", RowFunc: generateLargeData("Sheet1", 150000)},
        {Name: "Sheet2", RowFunc: generateLargeData("Sheet2", 2000)},
    }

    if err := exporter.Export(sheets); err != nil {
        fmt.Printf("Failed to export Excel file: %v\n", err)
    }
}

func generateLargeData(sheetName string, rowCount int) excelexporter.RowDataFunc {
    currentRow := 0
    return func() (excelexporter.Row, error) {
        if currentRow >= rowCount {
            return excelexporter.Row{}, nil
        }
        currentRow++
        return excelexporter.NewRow(
            fmt.Sprintf("%s-a%d", sheetName, currentRow),
            fmt.Sprintf("%s-b%d", sheetName, currentRow),
            fmt.Sprintf("%s-c%d", sheetName, currentRow),
        ), nil
    }
}

Exporting Data Using Channel

This example demonstrates how to use channels with the UseRowChan function to export data to an Excel file.

package main

import (
    "fmt"

    excelexporter "github.com/xelarion/excel-exporter"
    "github.com/xuri/excelize/v2"
)

func main() {
    exporter := excelexporter.New("test_channel.xlsx", true)
    sheetNames := []string{"SheetA", "SheetB"}
    sheets := make([]excelexporter.SheetData, len(sheetNames))
    for i, name := range sheetNames {
        sheets[i] = excelexporter.SheetData{
            Name:    name,
            RowFunc: excelexporter.UseRowChan(queryDataToChannelFunc(exporter, name)),
        }
    }

    if err := exporter.Export(sheets); err != nil {
        fmt.Printf("Failed to export Excel file with StreamWriter: %v\n", err)
    }
}

func queryDataToChannelFunc(exporter *excelexporter.Exporter, sheetName string) func(dataCh chan excelexporter.Row) error {
    return func(dataCh chan excelexporter.Row) error {
        titleStyle, _ := exporter.File.NewStyle(
            &excelize.Style{
                Font:      &excelize.Font{Color: "777777", Size: 14},
                Alignment: &excelize.Alignment{Horizontal: "center", Vertical: "center"},
            },
        )

        // Set column width
        if exporter.UseStreamWriter {
            // when use StreamWriter
            _ = exporter.StreamWriter.SetColWidth(1, 3, 30)
        } else {
            // when use memory
            _ = exporter.File.SetColWidth(exporter.CurrentSheet, "A", "C", 30)
        }

        dataCh <- excelexporter.Row{
            Cells: []excelize.Cell{
                {Value: "MergedTitle 1", StyleID: titleStyle},
                {Value: "", StyleID: titleStyle},
                {Value: "MergedTitle 2", StyleID: titleStyle},
            },
            // Merge cells
            MergeCells: []excelexporter.MergeCell{
                {TopLeftCell: "A1", BottomRightCell: "B1"},
            },
            // set row style, only useful when useStreamWriter is true
            RowOpts: []excelize.RowOpts{
                {Height: 20, StyleID: titleStyle},
            },
        }

        // Title
        dataCh <- excelexporter.Row{
            Cells: []excelize.Cell{
                {Value: "Title 1", StyleID: titleStyle},
                {Value: "Title 2", StyleID: titleStyle},
                {Value: "Title 3", StyleID: titleStyle},
            },
        }

        // Simulate querying data from the database and sending to channel
        for i := 0; i < 10; i++ {
            dataCh <- excelexporter.NewRow(
                fmt.Sprintf("%s-%d-1", sheetName, i),
                fmt.Sprintf("%s-%d-2", sheetName, i),
                fmt.Sprintf("%s-%d-3", sheetName, i),
            )
        }

        return nil
    }
}

API Reference

Exporter

The Exporter struct provides methods for exporting data to Excel files.

Methods

• New(fileName string, useStreamWriter bool) *Exporter: Creates a new Exporter.
• Export(sheets []SheetData) error: Exports the Excel file with the specified sheets.

SheetData

The SheetData struct represents the data for a single sheet.

Fields

• Name string: The name of the sheet.
• RowFunc RowDataFunc: A function that returns the next row of data.

Row

The Row struct represents a row of data in the Excel sheet.

Fields

• Cells []excelize.Cell: Cells in the row.
• MergeCells []MergeCell: Merged cells in the row.
• RowOpts []excelize.RowOpts: Options for the row.

MergeCell

The MergeCell struct defines a merged cell data.

Fields

• TopLeftCell string: The starting cell to be merged.
• BottomRightCell string: The ending cell to be merged.

UseRowChan

The UseRowChan function returns a RowDataFunc that uses a channel to send Row objects to the given function.

func UseRowChan(sendDataFunc func(dataCh chan Row) error) RowDataFunc

NewRow

The NewRow function creates a new Row with the specified cell values.

func NewRow(cellValues ...interface{}) Row

Running Tests

To run the tests for this package, use the following command:

go test -v ./...

License

This project is licensed under the MIT License.