duaj39673 2017-04-29 23:06
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最简单的Golang CGI表单示例

I'd appreciate some help with the most basic possible CGI program with a form input. I don't want to run a listener or use a framework or do anything beyond the most basic possible example. This is just to get my feet in the door, and I will add the bells and whistles later.

Here's a simple CGI app without a form input:

package main

import "fmt"
import "os"

func main() {
        ip := os.Getenv("REMOTE_ADDR")
        fmt.Printf("Content-type: text/plain

")
        fmt.Println(ip)
}

This prints my IP address when I go to https://example.com/cgi-bin/ip

However, the following code results in a 502 error:

package main

import (
        "fmt"
        "net/http"
        s "strings"
)

func main() {
        var r *http.Request

        fmt.Printf("Content-type: text/html

")
        fmt.Println("<!DOCTYPE html>")
        fmt.Println("<title>login</title>")
        r.ParseForm()
        username := r.FormValue("username")
        password := r.FormValue("password")
        if s.Compare(password, username) == 0 {
                fmt.Println("<p>invalid username/password")
        }
}

The nginx log says:

2017/04/29 22:55:12 [error] 45768#0: *802 upstream prematurely closed FastCGI stdout while reading response header from upstream, client: 192.0.2.80, server: example.com, request: "POST /cgi-bin/login HTTP/2.0", upstream: "fastcgi://unix:run/slowcgi.sock:", host: "example.com", referrer: "https://example.com/login.html"

The HTML for this form is:

<!DOCTYPE html>
<title>Username and password</title>

<form action="/cgi-bin/login" method="post">
<table>
<tr><td>Username:</td><td><input type="text" name="username"></td></tr>
<tr><td>Password:</td><td><input type="password" name="password"></td></tr>
<tr><td> </td><td><input type="submit" value="Submit"></td></tr>
</table>
</form>

Another note: this is nginx on OpenBSD, using slowcgi(8). Since my toy "ip" program works, I believe my Go code is the problem.

What am I doing wrong in my Go code? Thank you!

EDIT: I now have the following code, which doesn't compile. What am I doing wrong?

package main

import (
        "fmt"
        "os"
        "net/http/cgi"
)

func main() {
        httpReq, err := cgi.Request()
        if err != nil {
                fmt.Fprintf(os.Stderr, err.Error())
                os.Exit(1)
        }

        r := httpReq.ParseForm()
        username := r.FormValue("username")
        password := r.FormValue("password")

        fmt.Printf("Content-type: text/html

")
        fmt.Printf("<!DOCTYPE html>
")
        fmt.Printf("<p>username: %s
", username)
        fmt.Printf("<p>password: %s
", password)
}
  • 写回答

1条回答 默认 最新

  • dongyue9864 2017-04-30 22:08
    关注

    Since net/http/cgi is not working for you and looking at the error log from nginx mentioning FastCGI, you might need to use the net/http/fcgi package.

    If you look at its documentation you can see that you'll need to do a little bit more work to get access to the request.

    First declare a function that will be used to handle the requests:

    func myhandler(_ http.ResponseWriter, r *http.Request) {
    // handle request
}

    Then pass your new handler to the fcgi.Serve function.

    fcgi.Serve(nil, http.HandlerFunc(myhandler))

    Serve takes two parameters. The first one is a net.Listener, if passed in as nil, Serve will read the requests from stdin. The second one, is of type http.Handler which is an interface that the myhandler function, as is, does not implement but given its specific signature (func(http.ResponseWriter, *http.Request)) you can convert myhandler to an http.Handler using the http.HandlerFunc type.

    Full example:

    package main

import (
    "fmt"
    "net/http/fcgi"
    "os"
)

func myhandler(_ http.ResponseWriter, r *http.Request) {
    if err := r.ParseForm(); err != nil {
        fmt.Fprintf(os.Stderr, err.Error())
        os.Exit(1)
    }

    username := r.FormValue("username")
    password := r.FormValue("password")

    fmt.Printf("Content-type: text/html

")
    fmt.Printf("<!DOCTYPE html>
")
    fmt.Printf("<p>username: %s
", username)
    fmt.Printf("<p>password: %s
", password)
}

func main() {
    if err := fcgi.Serve(nil, http.HandlerFunc(myhandler)); err != nil {
        panic(err)
    }
}
    评论

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