patrickmn/rowsdos.go

## rowsdos.go
package main

// Demonstration of Golang weekly.2011-12-22 exp/sql + gopgsqldriver
// Keep-Alive DoS: *db.Query Rows.Close() is not automatic

import (
	"encoding/json"
	"exp/sql"
	"fmt"
	"net/http"
	"os"
	_ "github.com/jbarham/pgsqldriver"
)

var (
	db *sql.DB
	checkError = func(err error) {
		if err != nil {
			fmt.Println(err)
			os.Exit(1)
		}
	}
	html = `
<html>
    <head>
	<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
	<script>
	function poll(interval) {
	    $.ajax({
		url: "http://localhost:9000/",
                data: {
		    name: "Patrick",
		},
		success: function(food) {
		    $("div#wholikes").append("<p>Patrick likes "+food+"</p>");
		},
	    });
	    setTimeout(function() {poll(interval);}, interval);
	};
	$(document).ready(function() {
	    poll(20);
	});
	</script>
    </head>
    <body>
	<div id="wholikes"></div>
    </body>
</html>
`
	reqCount = 0
)

// # sudo -u postgres psql postgres
// -- DB SQL
// CREATE USER godos;
// ALTER USER godos WITH PASSWORD 'godos';
// CREATE DATABASE godos
//   WITH OWNER      = godos
//        ENCODING   = 'UTF8'
//        TABLESPACE = pg_default
//        LC_COLLATE = 'en_US.UTF-8'
//        LC_CTYPE   = 'en_US.UTF-8'
//        CONNECTION LIMIT = -1;
// GRANT ALL PRIVILEGES ON DATABASE godos TO godos;

func main() {
	db, _ = sql.Open("postgres", "host=localhost dbname=godos user=godos password=godos")
	db.Exec("DROP TABLE favfood")
	db.Exec("CREATE TABLE favfood(name VARCHAR(64), food VARCHAR(64))")
	db.Exec("INSERT INTO favfood(name, food) VALUES('Patrick', 'Eggs')")
	db.Exec("INSERT INTO favfood(name, food) VALUES('Patrick', 'Bacon')")
	http.Handle("/", http.HandlerFunc(Page))
	http.ListenAndServe(":9000", nil)
}

func Page(w http.ResponseWriter, req *http.Request) {
	// w.Header()["Connection"] = []string{"Close"} // Workaround: This closes the idle DB conn
	reqCount++
	fmt.Println("Request", reqCount)
	name := req.FormValue("name")
	if name != "" {
		foods := GetFoods(name)
		data, _ := json.Marshal(foods)
		w.Write(data)
	} else {
		fmt.Fprint(w, html)
	}
}

func GetFoods(name string) []string {
	var foods []string
	rows, err := db.Query("SELECT food FROM favfood WHERE name = $1", name)
	checkError(err)
	for rows.Next() {
		var food string
		err := rows.Scan(&food)
		checkError(err)
		foods = append(foods, food)
	}
	// rows.Close() // Should-be-automatic fix: This closes the idle DB conn
	return foods
}
	package main

	// Demonstration of Golang weekly.2011-12-22 exp/sql + gopgsqldriver
	// Keep-Alive DoS: *db.Query Rows.Close() is not automatic

	import (
	"encoding/json"
	"exp/sql"
	"fmt"
	"net/http"
	"os"
	_ "github.com/jbarham/pgsqldriver"
	)

	var (
	db *sql.DB
	checkError = func(err error) {
	if err != nil {
	fmt.Println(err)
	os.Exit(1)
	}
	}
	html = `
	<html>
	<head>
	<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
	<script>
	function poll(interval) {
	$.ajax({
	url: "http://localhost:9000/",
	data: {
	name: "Patrick",
	},
	success: function(food) {
	$("div#wholikes").append("<p>Patrick likes "+food+"</p>");
	},
	});
	setTimeout(function() {poll(interval);}, interval);
	};
	$(document).ready(function() {
	poll(20);
	});
	</script>
	</head>
	<body>
	<div id="wholikes"></div>
	</body>
	</html>
	`
	reqCount = 0
	)

	// # sudo -u postgres psql postgres
	// -- DB SQL
	// CREATE USER godos;
	// ALTER USER godos WITH PASSWORD 'godos';
	// CREATE DATABASE godos
	// WITH OWNER = godos
	// ENCODING = 'UTF8'
	// TABLESPACE = pg_default
	// LC_COLLATE = 'en_US.UTF-8'
	// LC_CTYPE = 'en_US.UTF-8'
	// CONNECTION LIMIT = -1;
	// GRANT ALL PRIVILEGES ON DATABASE godos TO godos;

	func main() {
	db, _ = sql.Open("postgres", "host=localhost dbname=godos user=godos password=godos")
	db.Exec("DROP TABLE favfood")
	db.Exec("CREATE TABLE favfood(name VARCHAR(64), food VARCHAR(64))")
	db.Exec("INSERT INTO favfood(name, food) VALUES('Patrick', 'Eggs')")
	db.Exec("INSERT INTO favfood(name, food) VALUES('Patrick', 'Bacon')")
	http.Handle("/", http.HandlerFunc(Page))
	http.ListenAndServe(":9000", nil)
	}

	func Page(w http.ResponseWriter, req *http.Request) {
	// w.Header()["Connection"] = []string{"Close"} // Workaround: This closes the idle DB conn
	reqCount++
	fmt.Println("Request", reqCount)
	name := req.FormValue("name")
	if name != "" {
	foods := GetFoods(name)
	data, _ := json.Marshal(foods)
	w.Write(data)
	} else {
	fmt.Fprint(w, html)
	}
	}

	func GetFoods(name string) []string {
	var foods []string
	rows, err := db.Query("SELECT food FROM favfood WHERE name = $1", name)
	checkError(err)
	for rows.Next() {
	var food string
	err := rows.Scan(&food)
	checkError(err)
	foods = append(foods, food)
	}
	// rows.Close() // Should-be-automatic fix: This closes the idle DB conn
	return foods
	}