Golang network disk construction

With the development of the Internet, the demand for network disks is increasing. However, network disk products on the market have frequently been complained about privacy leaks and other issues. Therefore, building a network disk of your own has become a trend. This article will introduce how to use golang to build a simple network disk.

1. Environment preparation

Using golang to build a network disk requires certain programming capabilities and the following environment preparation:

1.1 Necessary tools

• go >= 1.8
• godep
• git

1.2 Dependent library

• golang.org/x/crypto: In addition to the built-in encryption package of Go language, it provides more secure encryption algorithm support, including SHA256/384/512, RC4, DES, AES, etc.
• github.com/gin-gonic/gin: A high-performance HTTP framework that can be used to quickly write simple web applications, as well as more complex applications.
• github.com/go-xorm/core: Lightweight ORM framework for CRUD operations on databases.
• github.com/go-xorm/xorm: An enhanced version based on the core package, which provides simplified SQL generation, transactions, caching and multiple data source access, etc., suitable for data access in various large and small projects layer.

2. Project architecture

The back-end of the network disk is a file management system that reads files into memory and provides access services through an HTTP server. The front-end uses simple HTML/ CSS/JS pages enable interactivity. During the development process, we strictly followed the MVC design pattern and separated the three levels of Model, View, and Controller.

2.1 Model layer

The Model layer is mainly responsible for data access, extracting data from the underlying data storage, and then providing it to the Controller layer for business processing. In our system, CURD operations are mainly performed on files. We use the ORM framework xorm to abstract the underlying data and provide a simpler and clearer API.

The data model is defined using the Go language structure, as follows:

type User struct {
    Id int64
    Username string `xorm:"unique"`
    Password string
}

2.2 View layer

The View layer corresponds to the Presentation layer in the Web application and is mainly responsible for integrating the control layer The returned data will be rendered to the program interface, and the request data sent by the interface will be passed to the control layer for processing. In our system, the View layer is mainly responsible for handling front-end page docking.

We use the Gin framework to write View layer code. First, we need to set up a routing management. When we enter a certain URL, the corresponding processing function will be automatically called for processing. In the Gin framework, this is very easy to implement:

router := gin.Default()
router.GET("/files", handlers.ListFiles)
router.PUT("/files/:name", handlers.AddFile)
router.POST("/files/:name", handlers.UpdateFile)
router.DELETE("/files/:name", handlers.DeleteFile)
router.Run(":8020")

2.3 Controller layer

The Controller layer is responsible for processing requests, getting data to the View layer, and finally returning the processing results. In our system, the Controller layer is mainly responsible for processing business logic.

During the processing, we must first determine whether the user is logged in. If not logged in, jump to the login page, otherwise jump to the file list. Similarly, when the user requests a file, we need to first check whether the file exists. If it does not exist, return a 404 error page.

3. File operation

3.1 File upload

Before uploading a file, we must first perform a type check on the file. To prevent file types from being tampered with by analyzing HTTP packets, we recommend performing type checking on the front end. We use JavaScript's FileReader object to read uploaded files and block AJAX requests.

When the user chooses to upload a file, we will start to read the file asynchronously. After the reading is completed, the file will be uploaded to the server in binary mode. After the upload is successful, the file information is stored in the database for easy management.

3.2 File Download

When requesting to download a file, we use the HTTP service to directly return the file to the browser in the form of a stream. At the same time, we use the http.ServeContent function to transfer files and ensure that the file transfer is completely correct and controllable.

func (h Handler) DownloadFile(c gin.Context) {

fileName := c.Param("name")
filePath := h.filePath(fileName)
if _, err := os.Stat(filePath); os.IsNotExist(err) {
    c.String(http.StatusNotFound, "file not exist")
    return
}
c.Writer.Header().Add("Content-Disposition", fmt.Sprintf("attachment; filename=%s", fileName))
c.Writer.Header().Add("Content-Type", getContentType(fileName))
http.ServeFile(c.Writer, c.Request, filePath)

}

3.3 File deletion

File deletion It is a relatively simple operation. First, we need to check if the file exists and return an error message if it does not exist. Then we need to delete the file information from the database and finally delete the file from the disk.

func (h Handler) DeleteFile(c gin.Context) {

fileName := c.Param("name")
filePath := h.filePath(fileName)
if _, err := os.Stat(filePath); os.IsNotExist(err) {
    c.String(http.StatusNotFound, "file not exist")
    return
}
session := h.engine.NewSession()
defer session.Close()
if err := session.Begin(); err != nil {
    log.Printf("begin transaction failed: %s", err.Error())
    c.String(http.StatusInternalServerError, err.Error())
    return

}
if _, err := session.Delete(&File{FileName: fileName}); err != nil {
    session.Rollback()
    c.String(http.StatusInternalServerError, err.Error())
    return
}
if err := session.Commit(); err != nil {
    c.String(http.StatusInternalServerError, err.Error())
    return
}
if err := os.Remove(filePath); err != nil {
    c.String(http.StatusInternalServerError, err.Error())
    return
}
c.Header("Access-Control-Allow-Origin", "*")

c.String(http.StatusOK, "file delete success")

}

4. Security Policy

For To improve the security of the network disk system, we should strictly follow the following security policies during the development process:

4.1 Permission Control

Only authorized users are allowed to use various functions of the system, and other users cannot access and modify data.

4.2 Data Encryption

All sensitive information should be encrypted to avoid security incidents such as theft and tampering of information during transmission and storage.

4.3 Preventing network attacks

The system needs to adopt effective preventive measures to avoid attacks from the network, including but not limited to firewalls, anti-virus software, etc.

5. Summary

Through this article, we learned how to use golang to build a simple network disk system. During the development process, we strictly followed the MVC design pattern and separated modules to improve quality and maintainability. In addition, we have strictly considered system security, avoided some common security issues, and improved the reliability and security of the network disk system. We believe that for those who have just started programming in golang, this article can help them better understand the application scenarios of golang and quickly get started with project development.

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