go gin中间件关于 c.next()、c.abort()和return的使用小结_Golang

c.netx（）

测试代码

package main
import (
	"fmt"
	"github.com/gin-gonic/gin"
	"log"
	"net/http"
)
func main() {
	g := gin.new()
	g.use(middleware1(), middleware2())
	g.get("/", func(c *gin.context) {
		fmt.println("process request")
		c.json(http.statusok, "hello,world!")
	})
	err := g.run()
	if err != nil {
		log.fatal(err)
	}
}
func middleware1() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware1 start")
		c.next()
		fmt.println("middleware1 end")
	}
}
func middleware2() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware2 start")
		c.next()
		fmt.println("middleware2 end")
	}
}

访问 http://127.0.0.1:8080 执行结果如下，浏览器输出 “hello,world!”

middleware1 start
middleware2 start
process request
middleware2 end
middleware1 end

总结
中间件的执行顺序是按照注册的顺序执行的，在中间件中使用 c.next() 方法，会先执行c.next() 前面的，然后将控制权传递给下一个中间件或处理器，最后按照相反顺序执行中间件c.next() 后面的代码。 c.abort() 测试代码

package main
import (
	"fmt"
	"github.com/gin-gonic/gin"
	"log"
	"net/http"
)
func main() {
	g := gin.new()
	g.use(middleware1(), middleware2(), middleware3())
	g.get("/", func(c *gin.context) {
		fmt.println("process request")
		c.json(http.statusok, "hello,world!")
	})
	err := g.run()
	if err != nil {
		log.fatal(err)
	}
}
func middleware1() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware1 start")
		c.next()
		fmt.println("middleware1 end")
	}
}
func middleware2() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware2 start")
		c.abort()
		fmt.println("middleware2 end")
	}
}
func middleware3() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware3 start")
		c.next()
		fmt.println("middleware3 end")
	}
}

访问 http://127.0.0.1:8080 执行结果如下，浏览器无输出

middleware1 start
middleware2 start
middleware2 end
middleware1 end

总结
中间件的执行顺序是按照注册顺序执行的，中间件可以通过 c.abort() 来中止后续中间件或处理器的处理流程。

return 测试代码

package main
import (
	"fmt"
	"github.com/gin-gonic/gin"
	"log"
	"net/http"
)
func main() {
	g := gin.new()
	g.use(middleware1(), middleware2(), middleware3())
	g.get("/", func(c *gin.context) {
		fmt.println("process request")
		c.json(http.statusok, "hello,world!")
	})
	err := g.run()
	if err != nil {
		log.fatal(err)
	}
}
func middleware1() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware1 start")
		c.next()
		fmt.println("middleware1 end")
	}
}
func middleware2() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware2 start")
		return
		fmt.println("middleware2 end")
	}
}
func middleware3() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware3 start")
		c.next()
		fmt.println("middleware3 end")
	}
}

访问 http://127.0.0.1:8080 执行结果如下，浏览器输出 “hello,world!”

middleware1 start
middleware2 start
middleware3 start
process request
middleware3 end
middleware1 end

总结
中间件的执行顺序是按照注册顺序执行的，中间件可以通过 retrurn 来中止当前中间件的后续处理流程。

c.abort() +return 测试代码

package main
import (
	"fmt"
	"github.com/gin-gonic/gin"
	"log"
	"net/http"
)
func main() {
	g := gin.new()
	g.use(middleware1(), middleware2(), middleware3())
	g.get("/", func(c *gin.context) {
		fmt.println("process request")
		c.json(http.statusok, "hello,world!")
	})
	err := g.run()
	if err != nil {
		log.fatal(err)
	}
}
func middleware1() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware1 start")
		c.next()
		fmt.println("middleware1 end")
	}
}
func middleware2() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware2 start")
		c.abort()
		return
		fmt.println("middleware2 end")
	}
}
func middleware3() gin.handlerfunc {
	return func(c *gin.context) {
		fmt.println("middleware3 start")
		c.next()
		fmt.println("middleware3 end")
	}
}

访问 http://127.0.0.1:8080 执行结果如下，浏览器无输出