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Effective Go: update for new http interface.

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R=rsc, stephenm
CC=golang-dev
https://golang.org/cl/2310041
This commit is contained in:
Rob Pike 2010-09-29 11:12:52 -07:00
parent 4164d60cc2
commit 1edfb4cc75
1 changed files with 24 additions and 15 deletions
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39
doc/effective_go.html
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@ -1854,10 +1854,18 @@ that implements <code>Handler</code> can serve HTTP requests.
</p> </p>
<pre> <pre>
type Handler interface { type Handler interface {
ServeHTTP(*Conn, *Request) ServeHTTP(ResponseWriter, *Request)
} }
</pre> </pre>
<p> <p>
<code>ResponseWriter</code> is itself an interface that provides access
to the methods needed to return the response to the client.
Those methods include the standard <code>Write</code> method, so an
<code>http.ResponseWriter</code> can be used wherever an <code>io.Writer</code>
can be used.
<code>Request</code> is a struct containing a parsed representation
of the request from the client.
<p>
For brevity, let's ignore POSTs and assume HTTP requests are always For brevity, let's ignore POSTs and assume HTTP requests are always
GETs; that simplification does not affect the way the handlers are GETs; that simplification does not affect the way the handlers are
set up. Here's a trivial but complete implementation of a handler to set up. Here's a trivial but complete implementation of a handler to
@ -1870,13 +1878,14 @@ type Counter struct {
n int n int
} }
func (ctr *Counter) ServeHTTP(c *http.Conn, req *http.Request) { func (ctr *Counter) ServeHTTP(w http.ResponseWriter, req *http.Request) {
ctr.n++ ctr.n++
fmt.Fprintf(c, "counter = %d\n", ctr.n) fmt.Fprintf(w, "counter = %d\n", ctr.n)
} }
</pre> </pre>
<p> <p>
(Keeping with our theme, note how <code>Fprintf</code> can print to an HTTP connection.) (Keeping with our theme, note how <code>Fprintf</code> can print to an
<code>http.ResponseWriter</code>.)
For reference, here's how to attach such a server to a node on the URL tree. For reference, here's how to attach such a server to a node on the URL tree.
<pre> <pre>
import "http" import "http"
@ -1892,9 +1901,9 @@ But why make <code>Counter</code> a struct? An integer is all that's needed.
// Simpler counter server. // Simpler counter server.
type Counter int type Counter int
func (ctr *Counter) ServeHTTP(c *http.Conn, req *http.Request) { func (ctr *Counter) ServeHTTP(w http.ResponseWriter, req *http.Request) {
*ctr++ *ctr++
fmt.Fprintf(c, "counter = %d\n", *ctr) fmt.Fprintf(w, "counter = %d\n", *ctr)
} }
</pre> </pre>
<p> <p>
@ -1906,9 +1915,9 @@ has been visited? Tie a channel to the web page.
// (Probably want the channel to be buffered.) // (Probably want the channel to be buffered.)
type Chan chan *http.Request type Chan chan *http.Request
func (ch Chan) ServeHTTP(c *http.Conn, req *http.Request) { func (ch Chan) ServeHTTP(w http.ResponseWriter, req *http.Request) {
ch &lt;- req ch &lt;- req
fmt.Fprint(c, "notification sent") fmt.Fprint(w, "notification sent")
} }
</pre> </pre>
<p> <p>
@ -1935,11 +1944,11 @@ The <code>http</code> package contains this code:
// ordinary functions as HTTP handlers. If f is a function // ordinary functions as HTTP handlers. If f is a function
// with the appropriate signature, HandlerFunc(f) is a // with the appropriate signature, HandlerFunc(f) is a
// Handler object that calls f. // Handler object that calls f.
type HandlerFunc func(*Conn, *Request) type HandlerFunc func(ResponseWriter, *Request)
// ServeHTTP calls f(c, req). // ServeHTTP calls f(c, req).
func (f HandlerFunc) ServeHTTP(c *Conn, req *Request) { func (f HandlerFunc) ServeHTTP(w ResponseWriter, req *Request) {
f(c, req) f(w, req)
} }
</pre> </pre>
<p> <p>
@ -1955,9 +1964,9 @@ to have the right signature.
</p> </p>
<pre> <pre>
// Argument server. // Argument server.
func ArgServer(c *http.Conn, req *http.Request) { func ArgServer(w http.ResponseWriter, req *http.Request) {
for i, s := range os.Args { for i, s := range os.Args {
fmt.Fprintln(c, s) fmt.Fprintln(w, s)
} }
} }
</pre> </pre>
@ -2794,8 +2803,8 @@ func main() {
} }
} }
func QR(c *http.Conn, req *http.Request) { func QR(w http.ResponseWriter, req *http.Request) {
templ.Execute(req.FormValue("s"), c) templ.Execute(req.FormValue("s"), w)
} }
func UrlHtmlFormatter(w io.Writer, v interface{}, fmt string) { func UrlHtmlFormatter(w io.Writer, v interface{}, fmt string) {