Learn the file operation functions in Go language and implement the encryption, compression and upload function of files

Learn the file operation functions in Go language and implement the encryption, compression and upload function of files

Go language is a powerful and flexible programming language through which we can easily perform file operations. This article will introduce the file operation functions in the Go language, and implement the encryption and compression upload function of files through sample code.

1. File operation function
   In the Go language, file operations are mainly completed through the os package and the io/ioutil package. Commonly used file operation functions are:

1.1 Create files and directories:
os.Create(filename): Create a new file and return a file pointer.
os.Mkdir(dirname, perm): Create a new directory. The perm parameter is the permission of the directory.
os.MkdirAll(dirname, perm): Recursively create multi-level directories. The perm parameter is the permissions of the final directory.

1.2 Open a file:
os.Open(filename): Open the specified file and return a file pointer.
os.OpenFile(filename, flag, perm): Open the specified file, the flag parameter is the opening method, and the perm parameter is the file permission.

1.3 Read the file:
os.Read(file, data): Read data from the specified file and save it in data.

1.4 Write to file:
os.Write(file, data): Write the data in data to the specified file.

1.5 Close the file:
file.Close(): Close the specified file.

2. File Encryption
   To implement the file encryption function, we can use a simple XOR encryption algorithm. The sample code is as follows:

func encryptFile(filename string) error {
    file, err := os.OpenFile(filename, os.O_RDWR, 0644)
    if err != nil {
        return err
    }
    defer file.Close()

    fileInfo, err := file.Stat()
    if err != nil {
        return err
    }

    fileSize := fileInfo.Size()
    data := make([]byte, fileSize)

    _, err = file.Read(data)
    if err != nil {
        return err
    }

    // 异或加密算法
    key := []byte("mykey")
    for i := 0; i < len(data); i++ {
        data[i] = data[i] ^ key[i%len(key)]
    }

    _, err = file.Seek(0, 0)
    if err != nil {
        return err
    }

    _, err = file.Write(data)
    if err != nil {
        return err
    }

    file.Sync()

    return nil
}

The above code encrypts the data in the specified file through the XOR encryption algorithm and writes it back to the original file.

3. File Compression
   The Go language provides the gzip package to compress and decompress files. The sample code is as follows:

func compressFile(filename string) error {
    compressName := filename + ".gz"

    file, err := os.Open(filename)
    if err != nil {
        return err
    }
    defer file.Close()

    compressFile, err := os.Create(compressName)
    if err != nil {
        return err
    }
    defer compressFile.Close()

    // 创建gzip.Writer
    gz := gzip.NewWriter(compressFile)
    defer gz.Close()

    _, err = io.Copy(gz, file)
    if err != nil {
        return err
    }

    return nil
}

The above code will compress the specified file and save it as a .gz format file.

4. File upload
   File upload can be implemented using the common HTTP protocol, and the file is uploaded to the server through the POST method. The sample code is as follows:

func uploadFile(filename string, url string) error {
    file, err := os.Open(filename)
    if err != nil {
        return err
    }
    defer file.Close()

    // 使用multipart.Writer构建HTTP请求
    body := new(bytes.Buffer)
    writer := multipart.NewWriter(body)
    defer writer.Close()

    part, err := writer.CreateFormFile("file", filename)
    if err != nil {
        return err
    }

    _, err = io.Copy(part, file)
    if err != nil {
        return err
    }

    // 发送HTTP请求
    req, err := http.NewRequest("POST", url, body)
    if err != nil {
        return err
    }

    req.Header.Set("Content-Type", writer.FormDataContentType())

    httpClient := &http.Client{}
    _, err = httpClient.Do(req)
    if err != nil {
        return err
    }

    return nil
}

The above code uploads the specified file to the specified URL through the POST method.

Based on the above code, we can realize the encryption and compression upload function of files. The sample code is as follows:

func main() {
    // 加密文件
    err := encryptFile("test.txt")
    if err != nil {
        fmt.Println("加密文件失败：", err)
        return
    }

    // 压缩文件
    err = compressFile("test.txt")
    if err != nil {
        fmt.Println("压缩文件失败：", err)
        return
    }

    // 上传文件
    err = uploadFile("test.txt.gz", "http://example.com/upload")
    if err != nil {
        fmt.Println("上传文件失败：", err)
        return
    }

    fmt.Println("文件加密压缩上传成功")
}

Through the above code, we can realize the encryption and compression upload function of files. This is a simple example that you can extend and optimize as needed. I hope this article will be helpful to learn and use Go language for file operations!

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