Go Pentester - HTTP CLIENTS(1)

Building HTTP Clients that interact with a variety of security tools and resources.

Basic Preparation:

Go's net/HTTP standard package contains several convenience functions to quickly and easily send POST, GET, and HEAD requests, which are arguably the most common HTTP verbs you'll use.

Get(url string) (resp *Response, err error)
Head(url string) (resp *Response, err error)
Post(url string, bodyType string, body io.Reader) (resp *Response, err error)

Additional POST request, called PostForm()

func POSTFORM(url string, data url.Values) (resp *Response, err error)

No convenience functions exist for other HTTP verbs, such as PATCH, PUT, or DELETE. Use these verbs to interact with RESTful APIs.

Generate a Request using the NewRequest() function.

func NewRequest(methond, url string, body io.Reader) (resp *Response, err error)

Uses the ioutil.ReadAll() function to read data from the response body.

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
)

func main() {
	resp, err := http.Get("http://www.bing.com/robots.txt")
	if err != nil {
		log.Panicln(err)
	}
	// Print HTTP Status
	fmt.Println(resp.Status)

	//Read and display response body
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Panicln(err)
	}
	fmt.Println(string(body))
	resp.Body.Close()
}

Structured Response Parsing

JSON file

{"Message": "All is good with the world","Status": "Success"}

Go Parsing codes

package main

import (
	"encoding/json"
	"log"
	"net/http"
)

type Status struct {
	Message string
	Status string
}

func main() {
	res, err := http.Post(
		"http://IP:PORT/ping",
		"application/json",
		nil,
		)
	if err != nil {
		log.Fatalln(err)
	}

	var status Status
	if err := json.NewDecoder(res.Body).Decode(&status); err != nil {
		log.Fatalln(err)
	}
	defer res.Body.Close()
	log.Printf("%s -> %s\n", status.Status, status.Message)
}