golang networking

a simple get for http:

package main

import (
 "io";
 "strings";
  "log";
  "http";
  "fmt";
)

func main() {
 r, _, err := http.Get("http://www.google.com/robots.txt");
 var b []byte;
 if err == nil {
  b, err = io.ReadAll(r.Body);
  r.Body.Close();
 }

 if err != nil {
  log.Stderr(err)
 } else {
    fmt.Println(string(b));
  }
}

ok, it was not very simple.
r, _, err := http.Get("http://www.google.com/robots.txt");
get the Response in r. Response has: a StatusCode, Body and Header.

type Response struct {
    Status     string; // e.g. "200 OK"
    StatusCode int;    // e.g. 200
    Header map[string]string;
    Body io.ReadCloser;
}

Header is a simple string hash. Body is an interface to ReadCloser: all structures with Read and Close.
func Get(url string) (r *Response, finalURL string, err os.Error) is doing followings:
- do a redirection loop (maximal 10 times)
- parse the url
- send the request
- if should redirect, get the new location in header
- if should not redirect: return the result from send()

b, err = io.ReadAll(r.Body);
read the data from response body (which has a reader from connection) in a byte array.
fmt.Println(string(b));
printout the bytes as string

create a simple webserver

package main

import (
 "http";
 "io";
)

// hello world, the web server
func HelloServer(c *http.Conn, req *http.Request) {
 io.WriteString(c, "hello, world!\n");
}

// call a html page
func MyServerPage(c *http.Conn, req *http.Request) {
 http.ServeFile(c, req, "myhtml.html");
}

func main() {
 http.Handle("/hello", http.HandlerFunc(HelloServer));
 http.Handle("/my.html", http.HandlerFunc(MyServerPage));
 err := http.ListenAndServe(":8080", nil);
 if err != nil {
  panic("ListenAndServe: ", err.String())
 }
}

http.Handle("/hello", http.HandlerFunc(HelloServer));
set the hadler function HelloServer with "/hello".

err := http.ListenAndServe(":8080", nil);
start the TCP server on port 8080, that handle the registered handler.

io.WriteString(c, "hello, world!\n"); write a simple string.

http.ServeFile(c, req, "myhtml.html"); read the file and print it out.