HTTP Servers

Method Checks

Handlers often accept one HTTP method and reject others.

method check Checking a method keeps read and write actions separate.

Method Checks

method
method_checks.go
Replay: real traced execution (multi-file project)
package main

import "fmt"

type serverRequest struct {
	Method string
	Path   string
}

func main() {
	var method = "GET"
	req := serverRequest{Method: method, Path: "/items"}
	status := 200
	body := "list items"

	if req.Method == "POST" {
		status = 201
		body = "created item"
	}
	if req.Method != "GET" && req.Method != "POST" {
		status = 405
		body = "method not allowed"
	}

	fmt.Println("method=", req.Method)
	fmt.Println("status=", status)
	fmt.Println("body=", body)
}

package main

import "fmt"

type serverRequest struct {
	Method string
	Path   string
}

func main() {
	var method = "POST"
	req := serverRequest{Method: method, Path: "/items"}
	status := 200
	body := "list items"

	if req.Method == "POST" {
		status = 201
		body = "created item"
	}
	if req.Method != "GET" && req.Method != "POST" {
		status = 405
		body = "method not allowed"
	}

	fmt.Println("method=", req.Method)
	fmt.Println("status=", status)
	fmt.Println("body=", body)
}

package main

import "fmt"

type serverRequest struct {
	Method string
	Path   string
}

func main() {
	var method = "DELETE"
	req := serverRequest{Method: method, Path: "/items"}
	status := 200
	body := "list items"

	if req.Method == "POST" {
		status = 201
		body = "created item"
	}
	if req.Method != "GET" && req.Method != "POST" {
		status = 405
		body = "method not allowed"
	}

	fmt.Println("method=", req.Method)
	fmt.Println("status=", status)
	fmt.Println("body=", body)
}

  1. method ← "GET", req ← main.serverRequest{Method:"GET", Path:"/items"}

    10func main() {11  var method→ "GET" = "GET" //@method="POST", "DELETE"12  req→ main.serverRequest{Method:"GET", Path:"/items"} := serverRequest{Method: method"GET", Path: "/items"}13  status→ 200 := 20014  body→ "list items" := "list items"1516  if req.Method == "POST" {17    status = 20118    body = "created item"19  }20  if req.Method != "GET" && req.Method != "POST" {21    status = 40522    body = "method not allowed"23  }2425  fmt.Println("method=", req.Method"GET")26  fmt.Println("status=", status200)27  fmt.Println("body=", body"list items")28}
    outputmethod= GET
status= 200
body= list items

  1. method ← "POST", req ← main.serverRequest{Method:"POST", Path:"/items"}

    10func main() {11  var method→ "POST" = "POST"12  req→ main.serverRequest{Method:"POST", Path:"/items"} := serverRequest{Method: method"POST", Path: "/items"}13  status→ 200 := 20014  body→ "list items" := "list items"

  2. status ← 201, body ← "created item"

    16if req.Method"POST" == "POST" {17  status→ 201 = 20118  body→ "created item" = "created item"19}

  3. fmt.Println("method=", req.Method)

    25  fmt.Println("method=", req.Method"POST")26  fmt.Println("status=", status201)27  fmt.Println("body=", body"created item")28}
    outputmethod= POST
status= 201
body= created item

  1. method ← "DELETE", req ← main.serverRequest{Method:"DELETE", Path:"/items"}

    10func main() {11  var method→ "DELETE" = "DELETE"12  req→ main.serverRequest{Method:"DELETE", Path:"/items"} := serverRequest{Method: method"DELETE", Path: "/items"}13  status→ 200 := 20014  body→ "list items" := "list items"

  2. status ← 405, body ← "method not allowed"

    19}20if req.Method"DELETE" != "GET" && req.Method != "POST" {21  status→ 405 = 40522  body→ "method not allowed" = "method not allowed"23}

  3. fmt.Println("method=", req.Method)

    25  fmt.Println("method=", req.Method"DELETE")26  fmt.Println("status=", status405)27  fmt.Println("body=", body"method not allowed")28}
    outputmethod= DELETE
status= 405
body= method not allowed