Gin 系列讲座: Saas系统, Gin+Jwt+casbin RestFul Api 后端一战到底 : 7 单个多个文件上传参数绑定

Gin作为后端接收文件图片上传的参数传递

### 单个文件上传


#### 前台 web
```html
<!doctype html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>Single file upload</title>
</head>
<body>
<h1>Upload single file with fields</h1>

<form action="/upload" method="post" enctype="multipart/form-data">
    Name: <input type="text" name="name"><br>
    Email: <input type="email" name="email"><br>
    Files: <input type="file" name="file"><br><br>
    <input type="submit" value="Submit">
</form>
</body>

###注意上传前端需要form File input的name 一定是file

<form action="/upload" method="post" enctype="multipart/form-data"> 是关键属性

上传文件或者图片关键是 enctype="multipart/form-data" 不同与上节讲到的参数绑定

gin 后端

func main() {
	router := gin.Default()
	// Set a lower memory limit for multipart forms (default is 32 MiB)
	router.MaxMultipartMemory = 8 << 20 // 8 MiB
	router.Static("/", "./public")
	router.POST("/upload", func(c *gin.Context) {
		name := c.PostForm("name")
		email := c.PostForm("email")

		// Source
		file, err := c.FormFile("file")
		if err != nil {
			c.String(http.StatusBadRequest, fmt.Sprintf("get form err: %s", err.Error()))
			return
		}

		filename := filepath.Base(file.Filename)
		if err := c.SaveUploadedFile(file, filename); err != nil {
			c.String(http.StatusBadRequest, fmt.Sprintf("upload file err: %s", err.Error()))
			return
		}

		c.String(http.StatusOK, fmt.Sprintf("File %s uploaded successfully with fields name=%s and email=%s.", file.Filename, name, email))
	})
	router.Run(":8080")
}

后端解析

name := c.PostForm("name")
email := c.PostForm("email")
获取 html form 参数
file, err := c.FormFile("file")
获取form单个文件信息。

多文件上传

<html lang="en">
<head>
    <meta charset="utf-8">
    <title>Multiple file upload</title>
</head>
<body>
<h1>Upload multiple files with fields</h1>

<form action="/upload" method="post" enctype="multipart/form-data">
    Name: <input type="text" name="name"><br>
    Email: <input type="email" name="email"><br>
    Files: <input type="file" name="files" multiple><br><br>
    <input type="submit" value="Submit">
</form>
</body>
</html>html

关键点与单文件不同是

 type="file" name="files" multiple>

多文件上传gin 后端

unc main() {
	router := gin.Default()
	// Set a lower memory limit for multipart forms (default is 32 MiB)
	router.MaxMultipartMemory = 8 << 20 // 8 MiB
	router.Static("/", "./public")
	router.POST("/upload", func(c *gin.Context) {
		name := c.PostForm("name")
		email := c.PostForm("email")

		// Multipart form
		form, err := c.MultipartForm()
		if err != nil {
			c.String(http.StatusBadRequest, fmt.Sprintf("get form err: %s", err.Error()))
			return
		}
		files := form.File["files"]

		for _, file := range files {
			filename := filepath.Base(file.Filename)
			if err := c.SaveUploadedFile(file, filename); err != nil {
				c.String(http.StatusBadRequest, fmt.Sprintf("upload file err: %s", err.Error()))
				return
			}
		}

		c.String(http.StatusOK, fmt.Sprintf("Uploaded successfully %d files with fields name=%s and email=%s.", len(files), name, email))
	})
	router.Run(":8080")
}

多文件参数绑定

form, err := c.MultipartForm()
files := form.File["files"]

这样就获得了前端 name="files" 上传的文件列表了。

注意： form post请求